ARTICLE | doi:10.20944/preprints202311.1713.v1
Subject: Engineering, Marine Engineering Keywords: mooring line failure; failure combinations; Dezert-Smarandache theory; failure probability.
Online: 27 November 2023 (14:57:50 CET)
With the global warming and the frequent occurrences of harsh environments, mooring line failures are frequent. Response analysis of the platform structure and its residual mooring system under multiple mooring line failures is needed. Therefore, it is necessary to investigate the change law of platform motion response after mooring line failure to find out the reasons for the change. Studies for different failure combinations of mooring lines show that the variation of the steady-state equilibrium position of the platform is closely related to the stiffness, with a clear functional. The duration and amplitude of the transient response are mainly influenced by the Morison drag force. And it was found that the suspended mooring line reduced the motion responses. It is also found that the mooring line failure increased the effective tension and suspension length of the riser. Based on the improved Dezert-Smarandache theory (DSmT), it is calculated that mooring line failure has little effect on the failure probability in different zones of the riser.
REVIEW | doi:10.20944/preprints202307.1818.v3
Subject: Medicine And Pharmacology, Internal Medicine Keywords: fluid status; overhydration; hydration status; renal failure; kidney failure; heart failure; Ca-125; NT-pro-BNP; VEXUS; BIS
Online: 5 October 2023 (14:28:42 CEST)
Overhydration (OH) is a prevalent medical problem occuring in patients with kidney failure, but a specific marker has still not been found. Currently, clinicians employ techniques such as bioimpedance spectroscopy (BIS), ultrasound (US) markers of fluid overload or markers of heart and kidney function such as NT-pro-BNP, GFR or creatinine levels. New serum markers, including but not limited to Ca-125, Galectin-3 (Gal-3), Adrenomedullin (AMD) and Urocortin-2 (UCN-2), are presently under research, displaying promising results. The necessity to ascertain a more precise marker of overhydration is urgent mainly because physical examination is exceptionally imprecise. Signs and symptoms of fluid overload, like edema or gradual increase of body mass, are not always present, notably in patients with chronic kidney disease. This review paper summarizes actual knowledge of a patient's hydration status estimation, focusing specifically on kidney diseases.
REVIEW | doi:10.20944/preprints202105.0432.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: myofibroblasts; fibrosis; heart failure
Online: 19 May 2021 (07:55:59 CEST)
Fibroblasts are differentiated to myofibroblasts and produce collagen and other extracellular matrix when the heart is exposed to stresses. Myocardial infarction and pressure overload-induced hypertrophy are major stresses to induce differentiation of fibroblasts. Since collagen can compensate the missing tissue due to injury, appropriate production of collagen is beneficial for the injured heart against rupture. However, excessive deposition of collagen is called fibrosis and causes cardiac dysfunction. After fibroblasts are differentiated to myofibroblasts, myofibroblasts can further change their phenotypes. In addition, myofibroblasts are found to have a new function other than collagen production. Myofibroblasts have macrophage-like functions that engulf dead cells and secrete anti-inflammatory cytokines. So far, research on fibroblasts has been delayed due to the lack of available markers for selective isolation of fibroblasts. In recent years, it has become possible to genetically label fibroblasts, sequence the cells at single cell levels, and manipulate function or the number of cells. Based on new technologies, the origin of fibroblasts and myofibroblasts, time-dependent changes of fibroblast states after injury, and heterogeneity have been demonstrated. Here, I will introduce recent advances in fibroblasts and myofibroblasts.
ARTICLE | doi:10.20944/preprints202004.0506.v1
Online: 29 April 2020 (12:18:52 CEST)
This case study was conducted to disentangle the stories of unsuccessful LET examinees, their responses to failure, and their perspectives of the factors that contributed to their failure. The results demonstrate five themes related to the failure experience. Factors related to the physical environment, psychological well-being, and preparedness influenced the performance of the examinees. Contributory factors to failure provided several implications to teacher education practice. Educators have a responsibility to identify, inform, and intervene with students who are at high risk of failing the LET, and this responsibility could be executed capably. However, the role should be extended beyond graduation. The responsibility to help graduates transition from failure to licensure is the final step of successful undergraduate teacher education.
ARTICLE | doi:10.20944/preprints202109.0498.v1
Subject: Engineering, Civil Engineering Keywords: Railway; Track bed; Track bed failure; Railway track; Track bed failure remedy
Online: 29 September 2021 (14:23:30 CEST)
The polymer cures as it enters the ballast, forming a three-dimensional geo-composite reinforcing cage. Although there will be some adherence to the ballast in dry conditions, the polymer's primary job is to construct this reinforcing cage. Polymer penetration is controlled by altering the rheology of the polymer. The method is also said to include a built-in safety system, with the track reverting to a ballast state in the event of a polymer or geo-composite failure. Many of the sites were considered unmaintainable before the polymer was put. The design method was utilized to forecast track behaviour before and after treatment, allowing the most appropriate polymer rheology, polymer distribution, and loading levels to be designed in order to achieve optimum performance and confirm that the procedure worked. This method can be utilized to tackle these types of long-standing problems by displaying actual polymer application profiles at a typical important location.
ARTICLE | doi:10.20944/preprints202311.1913.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Congestive heart failure; echocardiography; hand-held echocardiogram; heart failure; images, advanced practice providers
Online: 29 November 2023 (23:04:44 CET)
Objectives: Evaluate hand-held echocardiography (HHE) performed and interpreted by trained Advanced Practice Providers (APPs) on hospitalized CHF patients for image quality and interpretation, by comparing against expert echocardiographer and SE findings. Background: Congestive heart failure (CHF) is associated with increased hospital admissions and mortality. While standard echocardiogram (SE) is the gold standard for cardiac assessment, it is not readily available. Hospitalized CHF patients require rapid assessment for expedited treatment. Methods: Over 6 months, five trained APPs performed HHE on hospitalized CHF patients and interpreted: a) Left ventricular (LV) size, b) LV ejection fraction (LVEF), and c) right atrial pressure (RAP). The study echocardiographer reviewed and blindly interpreted HHE images and compared with APPs and SE findings. Kappa-statistics determined the degree of agreement between APPs and study echocardiographer interpretation of HHE images and SE. Results: 80 CHF patients [age 73±14 years, 58% males; LVEF (by SE) 45±19%; 36.3% body mass indexes ≥30 kg/m2] were enrolled. HHE interpretation by APPs had good agreement for LVEF (kappa 0.79) with study echocardiographer and SE (kappa 0.74), and good agreement for RAP (kappa 0.67) with study echocardiographer. Correlation between absolute LVEF interpretation by study echocardiographer on HHE and SE was r=0.88 (p<0.0001). Conclusions: Trained APPs obtained diagnostic-quality HHE images and interpreted LV function and RAP in CHF patients, with good agreement with the study echocardiographer. LVEF by HHE correlated with LVEF by SE. Our study suggests trained APPs can use HHE to evaluate LVEF and RAP in CHF patients leading to expedited and optimized treatment.
ARTICLE | doi:10.20944/preprints202311.0121.v1
Online: 2 November 2023 (08:01:44 CET)
Buildings are subject to intrinsic and extrinsic failures at all stages of the construction process, i.e., design to occupancy (i.e., use) as several failure types can affect them. There are three basic steps for researching building failures: listing, cataloging, and solving/deciding whether highlighting the least invasive and lowest cost intervention. Therefore, this research presents some methods used in construction for the intervention prioritization and seeks to illustrate the most suitable methodology for different settings failure x diagnosis x intervention. Therefore, the most traditional tools are shown: BASICO, SWIFT, FEMEA, AAF, and GUT matrix, where a critical assessment of the strengths and weaknesses is carried out. After that, a case study on maintenance services for the moisture on the building facades was performed. Finally, the GUT matrix and the FMEA method are the best results
REVIEW | doi:10.20944/preprints202308.0192.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; gut; microbiome; relationship
Online: 2 August 2023 (10:05:19 CEST)
There is a bidirectional relationship between the heart and the gut. Gut microbiome is an excellent gut-homeostasis keeper since controls the growth of potentially harmful bacteria and protects the microbiota environment. There is evidence suggesting that diet rich in fatty acid can be metabolized and converted by gut microbiome and hepatic enzymes to trimethyl-amine N-oxide (TMAO) a product that is associated with atherogenesis, platelet dysfunction, thrombotic events, coronary artery disease, stroke, heart failure and ultimately death. Heart failure, by inducing gut ischemia and congestion and consequently gut barrier dysfunction promote an intestinal leak of microbes or even of their products, facilitating their entrance into the circulation and thus stimulating the low-grade inflammation and hence the immune response. Drugs used for heart failure may alter the gut microbiome, and conversely gut microbiome may modify the pharmacokinetic properties of the drugs. Modification of lifestyle based mainly on exercise and Mediterranean diet along with the use of pre- or probiotics may be beneficial to some extent for the gut microbiome environment. The potential role of gut microbiome in heart failure development and outcomes is a fruitful area of future research.
REVIEW | doi:10.20944/preprints202306.2262.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: ascites; liver failure; portal hypertension
Online: 30 June 2023 (13:40:03 CEST)
Ascites is a term that describes a pathological accumulation of fluid in a peritoneal cavity. It is generally a rare occurrence in a pediatric population and is most commonly associated with liver failure and cirrhosis. In that case, a diuretic treatment is usually implemented to relieve the ascites as it forms in the mechanism of water retention and water leakage from the portal venous system due to portal hypertension. It is important to note however that many other issues may cause ascites in children. Those require a catered approach suited to the pathomechanism of ascites formation in those underlying conditions. That is why a complex diagnostic process ought to be run in pediatric patients with ascites to correctly identify a condition causing it and provide the patient with adequate and thorough care.
ARTICLE | doi:10.20944/preprints202306.0800.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: hypertrophic cardiomyopathy; cardiomyopathies; heart failure
Online: 12 June 2023 (08:41:43 CEST)
Background: Hypertrophic Cardiomyopathy (HCM) is the most common inherited Cardiomyopathy. The hallmark of HCM is myocardial fibrosis which contributes to heart failure, arrhythmias, and sudden cardiac death (SCD). Objective: To identify the factors implicated in heart failure symptoms and functional capacity of patients with HCM. Methods: In this cohort study, 43 patients with HCM were recruited. According to functional capacity and symptoms presentation, patients were categorized according to NYHA classification, and echocardiographic measurements of left ventricle systolic and diastolic function have been conducted. The echocardiographic assessment of right vetriculo-arterial coupling (RVAC) has been made by calculating the tricuspid annular peak systolic tissue Doppler velocity (TASV)/estimated RV systolic pressure (RVSP) ratio. Results: Almost half, 22 (51%) of our study population present symptoms of heart failure and were categorized as the symptomatic group - NYHA 2 or higher. Maximum LVOT gradient, RVSP, and the ratio of E/e’ were higher in the “symptomatic” compared to the “asymptomatic” group. TASV was lower in the “symptomatic” compared to the asymptomatic group (11±1cm/sex vs. 13±2cm/sec, p=0.04). However, there was no difference in other potentially influential factors, such as heart rate or systemic blood pressure. The SCD risk score does not differ between the two studied groups. The RVAC (estimated with the TASV/RVSP ratio) was lower in the “symptomatic” compared with the “asymptomatic” group (0.32±0.09 vs. 0.46±0.11, p<0.001). Conclusion: A low RVAC (as TASV/RVSP ratio) value could represent an echocardiographic marker of right ventricular-arterial uncoupling in patients with HCM and may impaired functional status.
ARTICLE | doi:10.20944/preprints202305.0280.v1
Online: 5 May 2023 (03:05:46 CEST)
A study was conducted to predict failure stresses, failure locations, and their paths of initiation of perforated polymethyl methacrylate (PMMA) specimens as they were loaded using pins inserted into the holes. First, a series of experiments were conducted for perforated PMMA coupons. There were six different types of coupons. The test specimens had three different widths with a circular hole of a diameter of 8 mm, which was placed at two different locations along the specimen length. All the specimens were loaded using a pin inserted into the hole with three different pins of nominal diameters of 8 mm, 6 mm, and 5 mm, respectively. To predict the failure and compare the results against the experimental data, the recently proposed universal failure criterion was used in the study using finite element analyses. The failure criteria gave acceptable results as compared to the experimental data.
REVIEW | doi:10.20944/preprints202203.0301.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Heart Failure; Gravity; Ischemia; Brain
Online: 22 March 2022 (12:38:29 CET)
During the 90 days following hospitalization for acute heart failure, ejection fraction and type of discharge medications have been shown in clinical trials to have little effect on mortality. We examined the recent literature addressing brain-related etiologies of sudden death following heart failure. Two mechanisms of sudden unexpected death have been suggested to possibly result from 4 significant influences on pathophysiology in the brain. The two causes of death are severe cardiac arrhythmia, and neurogenic pulmonary edema. They are both mediated through the brainstem autonomic nuclei generally, and executed specifically through the dorsal motor nucleus of the vagus nerve. The four significant influences on pathophysiology in the brainstem autonomic nuclei are: 1) Hyper-stimulation of neurons in the solitary tract nucleus, increasing their metabolic requirements; 2) Inadequate blood flow at a vascular watershed terminus; 3) Additionally decreased blood flow following vasoconstriction related to relative hyperventilation and decreased pCO2 levels; 4) Gravitational ischemia in the brain—caused by the weight of the brain mass sitting above the brainstem. Changes in head tilt release gravitational ischemia in the brain. There is no specific head position (relative to gravity) that is considered favorable or unfavorable for an extended period of time (i.e. more than 24 hours). Even a small degree of head elevation, used in managing pulmonary congestion, may increase gravitational ischemia in the posterior fossa and brainstem. In this paper we suggest a new and important research avenue for intervening in cardiac arrhythmias, and preventing their occurrence, through the non-invasive use of head-tilting, and other head repositioning maneuvers. This could potentially help many geriatric patients with heart failure, who have decreased mobility in bed, and who tend to stay in one position longer, thereby increasing gravitational ischemia in the brain.
ARTICLE | doi:10.20944/preprints202010.0625.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: heart failure; cardiovascular; comparative; evolution
Online: 30 October 2020 (08:06:24 CET)
Heart failure with preserved ejection fraction (HFpEF) is a leading form of human cardiovascular disease and commonly associated with systemic hypertension. Unique evolved adaptations in giraffe myocardia may be a natural animal model of resistance to HFpEF. In humans, pressure-overload induced left ventricular thickening (PLVT) impairs diastolic relaxation, elevates left atrial pressures and may progress to heart failure with symptoms including exercise intolerance. In healthy giraffe, the left ventricle thickens as developmental neck lengthening widens the vertical distance between the heart and head increasing pressures needed to maintain constant brain perfusion. Yet, diastolic relaxation and exercise capacity are unimpaired, a critical adaptation for prey species such as giraffe. The proximate mechanisms underlying this unique cardiovascular physiology are not yet characterized. Developmental PLVT in giraffe emerges as a species-specific evolved adaptation which offers a roadmap for identifying innovations in therapeutic and prevention strategies for HFpEF.
REVIEW | doi:10.20944/preprints201910.0040.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: diabetes; exercise; cardiomyopathy; heart failure
Online: 3 October 2019 (13:59:22 CEST)
Diabetes mellitus is associated with cardiovascular, ophthalmic, and renal comorbidities. Among these, diabetic cardiomyopathy (DCM) causes the most severe symptoms and is considered to be a major health problem worldwide. Exercise is widely known as an effective strategy for the prevention and treatment of many chronic diseases. Importantly, the onset of complications arising from diabetes can be delayed or even prevented by exercise. Regular exercise is reported to have positive effects on diabetes mellitus and the development of DCM. The protective effects of exercise include the prevention of cardiac apoptosis, fibrosis, oxidative stress, and microvascular diseases, as well as improvement in cardiac mitochondrial function, and calcium regulation. The present review summarizes the recent findings to describe the potential mechanisms by which exercise may prevent DCM and heart failure.
ARTICLE | doi:10.20944/preprints201711.0062.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: sacubitril valsartan; heart failure; treatment
Online: 9 November 2017 (09:17:37 CET)
Introduction In sacubitril-valsartan (sacub/v), the effects of an angiotensin II receptor blocker (ARB) exerted by valsartan are strengthened by the addition of sacubitril, an inhibitor of neutral endopeptidases. PARADIGM - HF study proved this association to be superior to enalapril in reducing both all-cause death and cardiovascular mortality, as well as heart failure (HF) hospitalizations in patients with cardiac insufficiency and reduced left ventricular ejection fraction( HFREF) belonging to NYHA class II-IV. To test whether even in our experience sacub/v is associated with favorable outcomes concerning mortality and morbidity, an outpatient small population of HFREF patients was retrospectively studied, of whom one third was treated with sacub/v instead of conventional therapy with ACE -inhibitors or ARBs. Methods A retrospective cohort study was carried out to assess the effects of sacub/v in addition to beta-blocker and mineral receptor antagonist (MRA) in a group of HFREF patients in NYHA classes II-III compared with conventional therapy (comprising ACE inhibitor or ARB added to beta-blocker plus a MRA) administered in a second group of HFREF patients with comparable clinical features retrospectively enrolled as controls. In the two groups, the therapeutic regimen was established in accordance with the preferences of the treating physician. Additionally, in both groups, evidence-based drug therapy was supplemented by the adjunct of a loop diuretic, usually furosemide, at variable doses. The primary outcomes of interest were all-cause death and HF hospitalizations. Safety outcomes were symptomatic hypotension, angioedema, hyperkalemia and worsening renal function. Results Mortality at six months was 6.8% in patients under therapy with sacub/v versus 34% in those treated with conventional therapy (odds ratio[OR] = 0.14; 95% CI: 0.04-0.49). Moreover, HF hospitalizations in the observation period considered were 4.5% in sacub/v group versus 59% in the conventional therapy group (OR = 0.03; 95% CI: 0.01–0.14). Safety outcomes included in our study (angioedema, hyperkalemia, hypotension and worsening renal function) showed a comparable profile in the two groups, with evidence of good tolerability of sacub/v , except for the side - effect " hypotension" (PAS < 100 mm Hg) , found in 15.9% of patients under sacub/v versus 5.7% reported in controls (OR = 3.14; 95% CI: 0.94–10.55). Conclusions In our experience, sacub/v has yielded a strong protection against both all-cause death and HF hospitalizations at six months , in the absence of significant noxious side effects. Nevertheless, considering the retrospective character of the study and the relatively exiguous sample size, further post marketing observational studies would be desirable . In particular, studies aiming at exploring safety of the new pharmacologic principle, namely mainly focusing on hypotension and angioedema, are warranted, in order to validate further this very efficacious molecule for therapy of chronic HF, especially stable HFREF in NYHA classes II-III.
Subject: Biology And Life Sciences, Forestry Keywords: hurricane; tree risk assessment; urban forest strike team; species failure profile; likelihood of failure
Online: 24 April 2020 (04:37:51 CEST)
Trees in residential landscapes provide many benefits, but can injure persons and damage property when they fail. In hurricane-prone regions like Florida, USA, the regular occurrence of hurricanes has provided an opportunity to assess factors that influence the likelihood of wind-induced tree failure and develop species failure profiles. We assessed open-grown trees in Naples, Florida, following the passage of Hurricane Irma in September 2017 to determine the effect of relevant factors on the degree of damage sustained by individual trees. Of 4,034 assessed individuals (n = 15 species), 74% sustained no damage, 4% sustained only minor damage (i.e., minimal corrective pruning needed), 6% sustained significant damage (i.e., major corrective pruning needed), and 15% were whole tree failures (i.e., overturned trees or trees requiring removal). The proportion of individuals in each damage category varied among species, stem diameter at 1.4 m above ground, and the presence of utility lines, which was a proxy for maintenance. We compared our results with the findings of seven previous hurricanes in the region to explore species’ resilience in hurricanes.
ARTICLE | doi:10.20944/preprints201706.0099.v1
Subject: Engineering, Mechanical Engineering Keywords: double strap joint; failure load prediction; finite element analysis; steel; stress-based failure criterion.
Online: 21 June 2017 (03:26:57 CEST)
In the current study, the failure behavior of retrofitted steel structures was studied experimentally and theoretically with steel/CFRP double strap joints (DSJs) under quasi-static tensile loading. A series of DSJs with different bonding lengths are also considered and examined to experimentally assess the effective bond length. To predict the failure load values of the tested specimens, a new stress-based criterion, namely the point stress (PS) criterion is proposed. Although some theoretical predictive modelling for the strength between steel/CFRP joints under various loading conditions has been presented, in this work by using the new proposed approach, one can calculate rapidly and conveniently the failure loads of the steel/CFRP specimens. Furthermore, to assess the validity of the new proposed criterion, further experimental data on steel/CFRP DSJs available in the open literature are predicted using the PS criterion. Finally, it was found that a good agreement exists between the experimental results and the theoretical predictions based on the PS criterion.
ARTICLE | doi:10.20944/preprints202308.2148.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: HIV; children; drug resistance; virologic failure
Online: 31 August 2023 (09:25:35 CEST)
Increasing HIV drug resistance (DR) among children with HIV (CHIV) on antiretroviral treatment (ART) is concerning. CHIV ages 1-14 years enrolled March 2019 to December 2020 from five facilities in Kisumu County, Kenya were included. Children were randomized 1:1 to control (standard-of-care) or intervention (point-of-care viral load (POC VL) testing every three months with targeted genotypic drug resistance testing (DRT) for VF (> 1000 copies/ml)). A multidisciplinary committee reviewed CHIV with DRT results and offered treatment recommendations. We describe DR mutations and present logistic regression models to identify factors associated with clinically significant DR. We enrolled 704 children in the study; median age was 9 years (interquartile range (IQR) 7,12), 344 (49%) were female and median time on ART was 5 years (IQR 3, 8). During the study period, 106 (15%) children had DRT results (84 intervention and 22 control). DRT detected mutations associate with DR in all participants tested, with 93 (88%) having major mutations, including 51 (54%) with dual class resistance. A history of VF in prior 2 years (adjusted odds ratio (aOR) 11.1; 95% confidence interval (CI) 6.3, 20.0) and less than 2 years on ART at enrollment (aOR 2.2; 95% CI 1.1, 4.4) were associated with increased odds of major DR. DR is highly prevalent among CHIV on ART with VF in Kenya. Factors associated with drug resistance may be used to determine which children should be prioritized for DRT.
ARTICLE | doi:10.20944/preprints202305.0313.v1
Subject: Engineering, Aerospace Engineering Keywords: ANFIS; Decision-making; Failure prediction; Aviation
Online: 5 May 2023 (07:17:49 CEST)
Safety is very important in aviation since a loss of safety frequently results in both fatalities and financially damaging situations that are typically unrecoverable. Thus, achieving safety as much as possible is the primary goal of practically all aviation technology work. In this study, an Adaptive Neuro-Fuzzy Inference System (ANFIS)-based classifier is created to estimate the fault risk factor of airplanes. Five categories of real fleet data belonging to structure, electrical, avionic, motor systems, and incident statistics of the planes have been used for classifier development. A risk factor determination for each plane is the output of the developed intelligent classifier, and it can be used to identify general overhaul candidate planes and stop defects and crashes before they happen. The obtained results show that using ANFIS provides a great capability in processing many inputs and outputs depending on different types and classes in the aviation industry and thus predicting the failure risk of the airplane efficiently.
ARTICLE | doi:10.20944/preprints202209.0378.v1
Subject: Computer Science And Mathematics, Mathematics Keywords: Mathematics; Factors; Success; Failure; Students; Teachers;
Online: 26 September 2022 (05:35:23 CEST)
Background: Bangladeshi students from science, technology, engineering, and mathematics (STEM) often struggle with solving many mathematical problems in different pedagogic contexts. They mostly lack the considerable prior learning or strong basics required to cope with the teaching and learning materials used at the undergraduate levels, which leads many students to take readmissions every year. Objective: This research aims at investigating the factors affecting the success and deficit of university undergraduate mathematics students in Bangladesh. The mixed-method research incorporates quantitative and qualitative data analysis on the students' and teachers’ perspectives regarding the issues. The authors focus more on categorizing the reasons influencing effective mathematics pedagogies than on identifying new or unknown causes. Methodology: This study is outlined in three phases. The phases include i. Exploratory qualitative survey ii. Quantitative triangulation survey, iii. Explanatory semi-structured interviews. Findings: First, the qualitative survey exposes the important factors that highlight the student’s success and failure in mathematics. Next, the quantitative data confirm that there are some similarities and dissimilarities between students’ and teachers’ perceptions. Also, the coefficient correlation analysis shows male students lack consistency and passion for study resulting in poor performances. Conversely, female students emphasize the inability to connect mathematical theories to real-life usages, curriculum loads, and unavailable resources as the reasons for underperformance. Finally, the interview data demonstrate the students attribute their failure to inadequate practices, memorizing habits, poor teaching, low motivation, and external distractions. Also, students acknowledge the necessity of steady practice, clear understanding, regular study, and working strategies for successful mathematics education. Teachers emphasize students’ clear concepts, aptitude, motivation, and curiosity for successful learning. Conclusion: This conclusion proposes a fresh start with the local mathematics pedagogic practices by analyzing teacher-student feedback on the success and failure factors impacted by varied individual and contextual elements. The study offers inclusive feedback on the part of both stakeholders. However, an open discussion or interaction between students and teachers might be needed to enhance mutual trust and understanding between them.
ARTICLE | doi:10.20944/preprints202205.0313.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Failure Prediction; Asynchronous motor; Neural Network
Online: 24 May 2022 (03:37:35 CEST)
Three-phase motors are commonly adopted in several industrial contexts and their failures can result in costly downtime causing undesired service outages; this way, motor diagnostics is an issue that assumes great importance. To prevent their failures and timely face the considered service outages, a non-invasive method to identify electrical and mechanical faults in three-phase asynchronous electric motors is proposed in the paper. In particular, a measurement strategy along with a machine learning algorithm based on Artificial Neural Network is exploited to properly classify failures. In particular, digitized current samples of each motor phase are first processed by means of FFT and PSD in order to estimate the associated spectrum. Suitable features (in terms of frequency and amplitude of the spectral components) are then singled out to either train or feed a neural network acting as a classifier. The method is preliminary validated on a set of 28 electric motors, and its performance is compared with common state-of-art machine learning techniques. The obtained results show that the proposed methodology is able to reach accuracy levels greater than 98\% in identifying anomalous conditions of three-phase asynchronous motors.
ARTICLE | doi:10.20944/preprints202108.0179.v1
Subject: Engineering, Mechanical Engineering Keywords: aramid fibber; ballistic test; failure mechanism
Online: 9 August 2021 (08:04:46 CEST)
The main objective of this study focuses on designing and testing body protection systems using advanced materials based on aramid fibers, for high impact speeds of up to 410...430 m/s. The investigation of the failure mechanisms identifies issues of protective materials, major challenges and technological problems for efficient development of these systems. The authors presents an investigation on the failure processes and destructive stages of a ballistic package made of succesive layers of LFT SB1plus, taking into account the particular test conditions from NIJ Standard-0101.06 Ballistic Resistance of Body Armor. The main parameter of interest was the backface signature (BFS), but also details of projectile arrest and SEM investigaton could offer arguments in using this material for individual protection.
ARTICLE | doi:10.20944/preprints202105.0345.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Respiratory Failure; COVID19; Intravenous Immunoglobulin Therapy
Online: 14 May 2021 (15:04:29 CEST)
Adjunctive therapy with polyclonal intravenous immunoglobins (IVIg) is currently used for preventing or managing infections and sepsis, especially in immunocompromised patients. The pathobiology of COVID19 and the mechanisms of action of Ig led to consider this adjunctive therapy also in patients with respiratory failure by SARS-CoV2 infection. This manuscript report the rationale, the available data and the results of a structured consensus on intravenous Ig therapy in patients with severe COVID19. METHODS A panel of multidisciplinary experts defined the clinical phenotypes of COVID19 patients with severe respiratory failure and, after literature review, voted for the agreement on the rationale and the potential role of IVIg therapy for each phenotype. Due to the scarce evidence available, a modified RAND/UCLA appropriateness method was used. RESULTS Three different phenotypes of COVID19 patients with severe respiratory failure were identified: patients with an abrupt and dysregulated hyperinflammatory response (early phase), patients with suspected immune-paralysis (late phase), and patients with sepsis by hospital-acquired superinfection (sepsis by bacterial superinfection). The rationale for intravenous Ig therapy in the early phase was considered uncertain whereas the panellists considered appropriate its use in the late phase and patients with sepsis/septic shock by bacterial superinfection. CONCLUSION As with other immunotherapies, IVIg adjunctive therapy may a potential role in the managing of COVID19 patients. The ongoing trials will clarify the appropriate target population and the true effectiveness.
ARTICLE | doi:10.20944/preprints202009.0143.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: Composite; Micromechanics; Cell Method; Failure; Isolation
Online: 6 September 2020 (15:38:28 CEST)
In this study, the elastic properties of composite materials are investigated, considering the effects of separation of fiber-matrix joint boundary and matrix failure. In this method, by assuming periodic microstructure and using a linear approximation of the displacement field by applying continuity and equilibrium conditions, the composite fiber composite relation is determined. The effect of separation is assumed by introducing tangential and normal scalar parameters in the equations by assuming the displacement field jump at the common boundary. In order to express the effect of matrix micro-cracks, the fracture mechanics framework of continuous environments was used and the micro-cracks parallel to the fibers, perpendicular to the fibers and in the thickness direction with scalar parameters were expressed. At the end of the effect of these parameters the results are presented in graphs. The results show that the presence of defective joint at the joint boundary and the matrix micro-components reduce the hardness of the composite and thus it’s bearing load, which is more significant at the defective joint state.
BRIEF REPORT | doi:10.20944/preprints202004.0452.v1
Subject: Medicine And Pharmacology, Other Keywords: respiratory failure; stethoscope; ultrasound; COVID-19
Online: 25 April 2020 (02:31:18 CEST)
The current Covid-19 pandemic has hugely disrupted the delivery of routine and established medical care. Patients can develop a wide range of clinical signs and symptoms from a cough and fever to severe respiratory failure. There is an ongoing argument on a concise investigative pathway to ensure the safety of all healthcare workers. The stethoscope can help with any clinical respiratory assessment but the risk of cross infection is high. Computer tomography should not be routinely performed. There is a potential place for lung ultrasound but outcomes are not yet determined.
ARTICLE | doi:10.20944/preprints201909.0238.v1
Subject: Engineering, Control And Systems Engineering Keywords: Software runtime entropy; failure prediction; indicator
Online: 20 September 2019 (10:49:11 CEST)
With the development of computer science and software engineering, software becomes more and more complex. Traditional software reliability assurance techniques including software testing and evaluation can't ensure software reliable execution after being deployed. Software failure prediction techniques based on failure indicators can predict software failures according to abnormal indicator values. The latter can be collected using runtime monitoring techniques. An essential part of this method is finding proper indicators which have strong correlation with software failures. We propose a novel type of indicators in this work named software runtime entropy, which takes both software module execution time and call times into consideration. Three common open source software, grep, flex and gzip are used as study cases for finding the relationships between the indicators and software failures. Firstly, a series of fault injection experiments are conducted on those three software respectively. The decision tree algorithm is used to train those data to build the correlation models between software runtime entropy and software failures. Several common measures in machine learning domains such as accuracy, recall rates, and F-measure are used to evaluate the models. The decision tree models can be used as failure mechanisms to assist the failure prediction work. One can examine the value of runtime entropy and make a warning report when it ranges from the normal interval to abnormal one.
ARTICLE | doi:10.20944/preprints201903.0082.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: RAAS; Canine Congestive Heart Failure; Therapeutics
Online: 6 March 2019 (13:33:08 CET)
Congestive heart failure (CHF) is a major cause of morbidity and mortality with an increasing prevalence in human and canine populations. Similar to humans, overactivation of the renin-angiotensin aldosterone system is involved in the pathophysiology of CHF in dogs. Current therapeutic strategies for the management of canine CHF include the use of RAAS inhibitors, diuretics and inodilators. The present review summarizes data from our own research on the modulation of the renin-angiotensin cascade in dogs in dogs, together with new findings (including novel therapeutic targets) from the veterinary and the human literature.
REVIEW | doi:10.20944/preprints201902.0030.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: biomarkers; miRNAs; heart failure; system biology
Online: 4 February 2019 (11:44:17 CET)
Heart failure (HF) has several etiologies including myocardial infarction (MI) and left ventricular remodeling (LVR), but its progression remains difficult to predict in clinical practice. Systems biology analyses of LVR after MI predict molecular insights of this event such as modulation of microRNA (miRNA) that could be used as a signature of HF progression. To define a miRNA signature of LVR after MI, we use 2 systems biology approaches integrating either proteomic data generated from LV of post-MI rat induced by left coronary artery ligation or multi-omics data (proteins and non-coding RNAs) generated from plasma of post-MI patients from the REVE-2 study. The first approach predicts 13 miRNAs and 3 of these miRNAs were validated to be associated with LVR in vivo: miR-21-5p, miR-23a-3p and miR-222-3p. The second approach predicts 24 miRNAs among 1310 molecules and 6 of these miRNAs were selected to be associated with LVR in silico: miR-17-5p, miR-21-5p, miR-26b-5p, miR-222-3p, miR-335-5p and miR-375. We identified a signature of 7 microRNAs associated with LVR after MI that support the interest of integrative systems biology analyses to define a miRNA signature of HF progression.
ARTICLE | doi:10.20944/preprints201901.0220.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Laminaria japonica; polysaccharide; chronic renal failure
Online: 22 January 2019 (11:50:15 CET)
Chronic renal failure (CRF) is a major public health problem worldwide. In this work, we investigated the effects of a purified Laminaria japonica polysaccharide (LJP61A) on the renal function using adenine-induced CRF mice model. Results exhibited that adenine treatment caused serious renal pathological damages and elevation of serum creatinine and blood urea nitrogen of mice. However, these changes could be significantly reversed by the administration of LJP61A in a dose-dependent manner. Additionally, LJP61A could dramatically reduce the weight loss, improve the urine biochemical index, and regulate the electrolyte disturbance of CRF mice. These results suggested that the renal functions of adenine-induced CRF mice could be improved by LJP61A, which might be developed to a potential therapeutic agent for CRF patients.
ARTICLE | doi:10.20944/preprints201704.0118.v2
Subject: Engineering, Civil Engineering Keywords: bond; concrete; reinforcement; damage-plasticity; failure
Online: 25 August 2017 (08:01:21 CEST)
The structural performance of reinforced concrete relies heavily on the bond between reinforcement and concrete. In nonlinear finite element analyses, bond is either modelled by merged, also called perfect bond, or coincident with slip, also called bond-slip, approaches. Here, the performance of these two approaches for the modelling of failure of reinforced concrete was investigated using a damage-plasticity constitutive model in LS-DYNA. Firstly, the influence of element size on the response of tension-stiffening analyses with the two modelling approaches was investigated. Then, the results of the two approaches were compared for plain and fibre reinforced tension stiffening and a drop weight impact test. It was shown that only the coincident with slip approach provided mesh insensitive results. However, both approaches were capable of reproducing the overall response of the experiments in the form of load and displacements satisfactorily for the meshes used.
ARTICLE | doi:10.20944/preprints201608.0087.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: natriuretic peptides; heart failure; congestion; outcome
Online: 9 August 2016 (11:33:03 CEST)
Background According to some authors, a single isolated measurement of serum BNP executed on hospital admission would not be a sufficiently accurate method to predict the outcome of patients with ADHF. Aims For verifying this assumption, a retrospective study was conducted on patients hospitalized for ADHF. Our main objective was to ascertain whether there was any difference in midterm mortality among patients with rising BNP at discharge as compared to those with decreasing BNP at discharge. Methods Medical records were examined so as to make a partition of the ADHF patient population into two groups, the former characterized by a rise in BNP during hospitalization, and the latter exhibiting a decrease in BNP in the measurement taken at hospital discharge. Results 177 patients were enrolled in a retrospective study. Among them, 53 patients (29.94%) had increased BNPs at the time of discharge, whereas 124 (70.06%) showed decreases in serum BNP during their hospital stay. The group with patients who exhibited BNP increases at the time of discharge had higher degree of congestion evident in the higher frequency of persistent jugular venous distention and persistent orthopnea at discharge. Moreover, patients with increased BNP at the time of discharge had a lower reduction in inferior vena cava maximum diameter [1.58 ± 2.2 mm vs. 6.32 ± 1.82 mm; p (one-way ANOVA)=0.001]. In contrast, there was no significant difference in weight loss when patients with increased BNP at discharge were compared to those with no such increase. A total of 14 patients (7.9%) died during the six-month follow-up period. Cox proportional hazard analysis revealed that BNP increase at the time of discharge was an independent predictor of six-month all-cause mortality after adjustment for age, sodium at discharge, creatinine at discharge and New York Heart Association (NYHA) class at discharge (hazard ratio 34.49; 95% confidence intervals: 4.55–261.06; P =0.001). Conclusions Among patients with history of ADHF, more elevated BNP levels at the time of discharge from the hospital compared to those detected at admission identify a patient subset with higher grade of congestion and higher six-month mortality.
ARTICLE | doi:10.20944/preprints202309.1415.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: COVID-19; COPD; smoking; mortality; respiratory failure
Online: 21 September 2023 (07:09:02 CEST)
Background: The global pandemic of coronavirus disease 2019 (COVID-19) resulted to many deaths from fulminant respiratory failure. Chronic obstructive pulmonary disease (COPD) is the leading cause of morbidity and mortality worldwide. There has been great concern regarding the impact of COPD on COVID-19 illness. Methods: Data from the Philippine CORONA Study were analyzed to determine the association of COPD and COVID-19 in terms of mortality, disease severity, respiratory failure, mechanical ventilation, and lengths of stay in the intensive care unit (ICU) and hospital. The influence of smoking on COVID-19 disease severity and mortality were also reviewed. Results: A total of 10,881 patients were included in the study and 156 (1.4%) patients had been diagnosed with COPD. Majority of COVID-19 patients with COPD had other existing comorbidities: hypertension, diabetes mellitus, chronic cardiac disease, and chronic kidney disease. COPD patients more commonly present with severe or critical COVID-19. COPD patients with COVID-19 were at higher risk to experience in-hospital mortality, respiratory failure, and to be admitted in the ICU. Smokers were more likely to present with higher COVID-19 severity and experience in-hospital mortality. Conclusion: Our study supports that the growing evidence that COPD among COVID-19 patients is a risk for higher mortality, more severe form of COVID-19, higher ICU admission, and higher respiratory failure needing ventilatory support. Smoking increases risk for developing severe COVID-19 and mortality.
ARTICLE | doi:10.20944/preprints202306.1359.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: left atrial function, heart failure; stepwise exercise
Online: 19 June 2023 (12:59:37 CEST)
Background: the aim of this study was to assess acute changes on left atrial (LA) function a during a progressive exercise in patients with heart failure with mid-range ejection fraction (HFmrEF) in comparison to healthy controls (HS). Methods: twenty patients with established HFmrEF were compared with 10 HS, age-matched controls. All subiects performed a stepwise exercise test on cyclette. Echocardiography was performed at baseline, during submaximal effort, at peak of exercise, and after 5 minutes of recovery. Results: HS obtained an higher value of METs at peak exercise than HFmrEF (7.4 vs 5.6; between group p 0.002). Heart rate and systolic blood pressure presented a greater increase in the HS group than in HFmrEF (between-groups p 0.006 and p 0.003 respectively). In the HFmrEF group peak atrial longitudinal strain (PALS), and conduit strain were both increased at submaximal exercise (p<0.05 for both versus baseline) and remained constant at peak exercise. Peak atrial contraction strain (PACS) did not show significant changes during the exercise. In the control group PALS and PACS increased significantly at submaximal level (p<0.05 for both versus baseline) but PALS returned near baseline values at peak exercise; conduit strain decreased progressively during the exercise in HS. Stroke volume (SV) increased in both groups at submaximal exercise; at peak exercise SV remained constant in the HFmrEF while it decreased in controls (between-groups p 0.002). Conclusions: Patient with HFmrEF, show a proper increase of LA reservoir function during incremental exercise that contributes to maintain SV throughout the exercise.
ARTICLE | doi:10.20944/preprints202306.0014.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: SGLT2 inhibition; empagliflozin; heart failure; interleukin 6
Online: 1 June 2023 (03:33:38 CEST)
Background: Inhibition of sodium-glucose co-transporter 2 (SGLT-2) has been shown to be beneficial in the treatment of diabetic and non-diabetic patients with heart failure with reduced ejection fraction (HFrEF). The underlying mechanisms are incompletely understood. The present prospective study investigates for the first time the effect of empagliflozin on various soluble markers of inflammation in HFrEF. Methods: We included 50 inpatients with HFrEF and diabetes mellitus type 2. Half of the patients received a therapy with the SGLT-2-inhibitor empagliflozin in addition to standard medication, the other half of the patients did not receive empagliflozin and were considered as control group. Quality of life, functional status and soluble immunological parameters in serum were assessed at baseline and after 3 months. Results: Baseline characteristics of both groups revealed no significant differences. Patients on empagliflozin demonstrated a significant improvement in the Minnesota living with heart failure questionnaire (baseline 44.2 ± 20.2 vs. 24 ± 17.7; p<0.001), in distance in the 6-minute walk test (baseline 343 ± 145 m vs. 450 ± 115 m; p<0.001) and in soluble interleukin-6 level (baseline 21.7 ± 21.8 pg/ml vs. 13.7 ± 15.8 pg/ml; p=0.008). There was no significant change of these or other parameters in the control group (p>0.05 each). Conclusions: The empagliflozin-induced improvement of quality of life and functional capacity in patients with HFrEF and type 2 diabetes mellitus is accompanied by a substantial reduction of interleukin-6 levels. Thus, antiinflammatory effects may contribute to the benefits of SGLT2-inhibitors in heart failure.
ARTICLE | doi:10.20944/preprints202305.1056.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; hospitalization; cardiovascular outcomes; electronic consultation
Online: 15 May 2023 (15:30:16 CEST)
(1) Objectives. Patients with heart failure (HF) who experience hospitalizations for worsening HF (HFH) are at high risk of subsequent events. We aimed to evaluate the impact of an outpatient care management program that includes a clinician-to-clinician e-consultation using an integrated electronic medical record in a healthcare area with a widely dispersed population on delay time in care, hospital admissions, and mortality in a high-risk group of patients with HF and previous episodes of HFH. (2) Methods. We selected 6,444 HF patients who visited the cardiology service at least once between 2010 and 2021. Of these, 4,851 were attended in e-consult, and 2,008 in one-time in-person consultations. In 2,230 HF patients, there was documentation of a previous episode of HFH. Using an interrupted time series regression model, we analysed the impact of incorporating e-consult into the health care model in the group of patients with HFH and evaluated the elapsed time to cardiology care, heart failure (HF), cardiovascular (CV), and all-cause hospital admissions and mortality, calculating the incidence relative risk (iRR). (3) Results. In the group of patients with previous HF hospitalizations, the introduction of e-consult substantially decreased waiting times to cardiology care. The time elapsed to care after e-consult implementation was significantly reduced compared with the previous in-person period (8.6 [8.7] vs 55.4 [79.9] days, p<0.001). In that group of patients, after e-consult implantation, hospital admissions for HF were reduced (iRR [CI95%]: 0,837 [0,840-0,833]), 0,900 [0,862-0,949] for CV and 0,699 [0,678-0,726] for all-cause hospitalizations. There was also lower mortality (iRR [CI95%]: 0.715 [0.657-0.798] due to HF, 0,737 [0.764-0.706] for CV and 0,687 [0.652-0,718] for all-cause). The improved outcomes after e-consultation implementation were significantly higher in the group of patients with previous HFH and were independent of the patient’s clinical characteristics managed during the in-person or e-consultation periods. (4) Conclusions. In HF patients with previous HFH, an outpatient care program that includes an e-consult significantly reduced waiting times to cardiology care and was safe, with a lower rate of hospital admissions and mortality in the first year.
ARTICLE | doi:10.20944/preprints202305.0387.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: concurrent training; heart failure; left atrial dysfunction
Online: 6 May 2023 (07:51:04 CEST)
Left atrial dysfunction is associated with exercise intolerance and poor prognosis in heart failure (HF). The effects of exercise training on atrial function in patients with HF with mid-range ejection fraction (HFmrEF) are unknown. The purpose of the present study was to assess the effects of a 12-weeks supervised concurrent, aerobic continuous plus resistance, exercise training (SCT) pro-gram on left atrial function of patients with HFmrEF. The study included 70 stable patients, who were randomly assigned into two groups: SCT with (three session/week) or a control (CON) group directed to follow contemporary exercise preventive guidelines at home. Before starting the training program and at 12-weeks, all patients performed: ergometric test, 6-minute walk test and echocardiography. At 12-weeks, exercise duration at ergometric test and distance walked at 6-minute walk test presented a significant greater increase in the SCT compared to control (be-tween-groups p 0.0001 and p 0.004 respectively). Peak atrial longitudinal strain and conduit strain presented an increase of 29% and 34% respectively in the SCT and were unchanged in the CON (between-groups p 0.008 and p 0.001 respectively). Peak atrial contraction strain increased of 21% in the SCT with no changes in the CON (between-groups p 0.002). Left ventricular global longi-tudinal strain increased significantly SCT compared to control (between-groups p 0.03). In con-clusions SCT improved left atrial and left ventricular function in HFmrEF
ARTICLE | doi:10.20944/preprints202207.0198.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Magnesium deficiency; Body composition; Chronic kidney failure.
Online: 13 July 2022 (09:27:18 CEST)
(1) Background: Reduced magnesium (Mg) levels may be associated with a faster de-cline in renal function. The aim of this study was to evaluate the association of serum and uri-nary Mg levels with body composition and inflammatory markers; (2) Methods: Lon-gitudinal study with patients with chronic kidney disease undergoing non-dialysis treatment in stages 3A, 3B and 4. Venous samples were collected after a 12-hour night fast. Body composition was evaluated by Double X-Ray Emission Absorptiometry and Air Displacement Plethysmog-raphy; (3) Results: The sample consisted of 134 patients. In the adjusted linear regression model, uric acid, percentage of lean mass and ali-mentar intake of Mg were positively associated with the sergic Mg. Triglyceride levels, WC and fat mass percentage were negatively associated with serum Mg. For the Mg urinal, in the adjusted model, the eGFR (estimated glomerular filtration rate), IL (interleukin 6), food intake of Mg and the percentage of lean mass showed a positive correlation.; (4) Conclusions: Serum Mg levels were positively associated with lean mass and negatively with total and central body fat and urinary Mg was positively associated with IL6 and lean mass.
REVIEW | doi:10.20944/preprints202112.0172.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: monocyte subset; heart failure; inflammation; cytokine; macrophage
Online: 10 December 2021 (11:54:31 CET)
Chronic heart failure (CHF) results when heart cannot constantly supply the body tissues with oxygen and required nutrients, and it can be categorized as heart failure (HF) with preserved ejection fraction (HFpEF), and HF with reduced ejection fraction (HFrEF). There are different causes and mechanisms of the HF pathogenesis; however, the inflammation can be regarded as one of the factors promoting both HFrEF and HFpEF. Monocytes, a subgroup of leucocytes, are known as cellular mediators in response to cardiovascular injury and are closely related to inflammatory reactions. These cells are a vital component of the immune system and are the source of macrophages, which participate in cardiac tissue repair after injury. However, the monocytes are not homogenous as thought, and thus can present different functions under different cardiovascular disease conditions. In addition, there is still an open question whether the functions of monocytes and macrophages should be regarded as a cause or a consequence in CHF development. Therefore, our aim was to summarize the current studies on the function of various monocyte subsets in CHF with a focus on the role of a certain monocyte subset in HFpEF and HFrEF patients, and the relation to inflammatory markers.
REVIEW | doi:10.20944/preprints202102.0519.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: rockfall; failure; propagation; hazard; risk; probability; frequency
Online: 23 February 2021 (14:23:02 CET)
There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests to use terms that appear to be the more logic and explicit as possible, and describes methods to derive some of the main hazard and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized hazards and diffused hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the propagation probability and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (reach frequency) can be derived. However, when the element at risk is not replaced or repaired, the probability that it is impacted by at least one rockfall must be considered.
ARTICLE | doi:10.20944/preprints202011.0185.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: heart failure; 6-minute walk test; prognosis
Online: 4 November 2020 (10:08:38 CET)
Background: The 6-minute walk test (6MWT) is a simple and low-cost method that allows assessment of functional capacity in patients with heart failure (HF). However, the prognostic role of 6MWT in HF remains uncertain. Objectives: We aimed to evaluate the 6MWT as a predictor of mid-term adverse outcomes in patients with HF with mid-range and reduced ejection fraction. Methods: Prospective single-center cohort study that included patients with HF with an ejection fraction under 50% at a specialized outpatient HF service. Patients underwent the 6MWT on admission and were compared according to the distance walked: Group I walked ≥350 meters and group II <350 meters. The primary outcome was a composite of death from any cause or hospitalization for HF decompensation in one-year follow-up. Secondary outcomes were the components of the primary outcome in an isolated analysis. Results: Sixty patients were included, 43.3% male, with a mean age of 61.1 ± 12.9 years and ejection fraction 34.3 ± 10.1%. 52 patients (86.7%) were on guideline-directed triple therapy for HF. The average distance walked in the 6MWT was 395.1 ± 98.8 meters, with 40 patients (66.7%) in group I and 20 (33.3%) in group II. The primary outcome in groups I and II were, respectively, 15,0% and 35,0% (p=0.05). One-year mortality was 5.0% vs 15.0% (p=0.18) and the hospitalization rate was 10.0% vs 20.0% (p=0.28). Conclusions: There was no association of distance <350 meters in the 6MWT with the primary outcome in patients with HF. Despite the higher occurrence of outcomes in group II, the difference was not statistically significant in this analysis. On a selective basis, the 6MWT may be a useful tool for prognostic stratification in HF, if combined with other methods.
ARTICLE | doi:10.20944/preprints202011.0003.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Heart Failure; Acute Kidney Injury; Prognosis; Mortality.
Online: 2 November 2020 (08:09:49 CET)
Introduction: Decompensated heart failure (HF) is a complex and debilitating syndrome, which constitutes a severe emergency condition with high morbidity and mortality. The kidneys play fundamental roles in the pathophysiology of HF and, in the context of decompensations, acute kidney injury (AKI) has a bilateral cause-and-effect relationship, which can significantly worsen prognosis. However, the interaction between AKI and decompensated HF is poorly understood. Objective: This study aimed to assess the occurrence of AKI in patients hospitalized due to decompensated HF and to analyze its prognostic impact during hospitalization. Methods: Prospective single-center observational study that included patients hospitalized due to decompensated HF in a tertiary-level teaching hospital, conducted between July 2017 and January 2020. Patients who developed AKI during hospitalization were compared with those who did not develop it, until hospital discharge or death. AKI was defined as a serum creatinine increase greater than or equal to 0.3 mg/dl in 48 hours, a 1.5-fold increase in baseline creatinine in seven days or urinary volume <0.5 ml/kg/h during six hours, according to the Acute Kidney Injury Network (AKIN) criteria. The endpoints analyzed were death, need for invasive mechanical ventilation (IMV) and length of hospital stay. The Wilcoxon, Mann-Whitney and unpaired student t tests were used. Results: Ninety-nine patients were included, with a mean age of 65.4 ± 14 years, of which 47 (47.5%) were male and 52 (52.5%) were female. Reduced ejection fraction was observed in 77.8% of patients, whilst 22.2% had a diagnosis of HF with preserved EF. The decompensation clinical classifications were: dry and warm = 7 (7.1%), wet and warm = 72 (72.7%), wet and cold = 15 (15.1%) and dry and cold = 5 (5.1%). The average left ventricular ejection fraction was 38.3% ± 15. AKI ocurred in 22 patients (22.2%). Comparison between patients who evolved with and without AKI showed higher mortality (36.4% vs 10.4%, p = 0.004) and the need for IMV (54.5% vs 13%, p = 0.0001) in the first group. There was no significant difference regarding the length of in-hospital stay (22.9 ± 19 vs 18.8 ± 16 days, p = 0.26). Conclusions: The occurrence of AKI was frequent in patients with decompensated HF requiring hospitalization, affecting approximately one out of five patients. This complication was significantly associated with increased mortality and the need for IMV during hospitalization.
REVIEW | doi:10.20944/preprints202001.0277.v2
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: statin; arthroplasty; revision; failure; osseointegration; osteolysis; loosening
Online: 20 August 2020 (09:32:07 CEST)
Osteoarthritis is a painful, disabling condition which is increasing in prevalence as a result of an ageing population. With no recognised disease limiting therapeutics, arthroplasty of the hip and knee is the most common and effective treatment for lower limb osteoarthritis, however lower limb arthroplasty has a finite life-span and a proportion of patients will require revision arthroplasty. With increasing life expectancy and an increasing proportion of younger (<65 years) patients undergoing arthroplasty, the demand for revision arthroplasty after implant failure is also set to increase. Statins are cholesterol modulating drugs widely used for cardiovascular risk reduction which have been noted to have pleiotropic effects including potentially influencing arthroplasty survival. In vitro studies have demonstrated pleiotropic effects in human bone cells, including enhancement of osteoblastogenesis following simvastatin exposure, and in vivo studies have demonstrated that intraperitoneal simvastatin can increase peri-implant bone growth in rats following titanium tibial implant insertion. There is evidence also that statins may also influence osseointegration, enhancing bone growth at the bone-implant interface, subsequently improving the functional survival of implants. Data from the Danish Hip Arthroplasty Registry and Clinical Practice Research Datalink in the UK suggest a reduction in the risk of lower limb revision arthroplasty in statin ever-users vs never users, and a time dependent effect of statin administration on reduction in risk of revision. In this article we review the clinical and scientific evidence linking statins and risk of revision arthroplasty.
REVIEW | doi:10.20944/preprints202006.0045.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: ARDS; COVID-19; Berlin Criteria; Respiratory Failure
Online: 5 June 2020 (13:54:36 CEST)
Introduction: The exponential growth of the SARS-CoV-2 virus transmission during the first months of 2020 has placed substantial pressure on health systems worldwide. The complications derived from the novel coronavirus disease (COVID-19) vary in due to comorbidities, sex and age, with more than 50% of the patients who require some level of intensive care developing acute respiratory distress syndrome (ARDS). Areas covered: Various complications caused by SARS-CoV-2 infection have been identified, the most lethal being the acute respiratory distress syndrome, caused most likely by the presence of severe immune cell response and the concomitant alveolus inflammation. The authors carried out an extensive and comprehensive literature review on SARS-CoV-2 infection, the clinical, pathological and radiological presentation as well as the current treatment strategies. Expert Opinion Elevation of inflammatory biomarkers is a common trend among seriously ill patients. The information available strongly suggests that in COVID-19 patients, their altered immune response, including a massive cytokine storm, is responsible for the further damage evidenced among ARDS patients. The increasingly high number of scientific articles and evidence available can only suggest that the individualization of each case is the norm, not all patients with acute respiratory failure due to COVID-19 meet the Berlin definition and therefore ARDS should be considered as a heterogeneous disease, with a wide range in the expression of its severity and clinical manifestations.
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: allograft, resorption, sclerotic bone, exfoliation, bone failure
Online: 24 April 2019 (12:33:49 CEST)
AbstractCadaver bone is possibly the most common transplant material used today. Common types of cadaver bone transplants are freeze-dried bone allografts and xenografts. Studies have shown that mineralized freeze-dried bone allografts have the same percentage of retained bone graft particles at different time points, indicating that these materials are never resorbed. However, it is commonly accepted by clinicians that these materials are resorbed and convert the graft site into normal bone. This histologic study was undertaken to determine the fate of mineralized freeze-dried bone allograft particles grafted into human extraction sockets. Materials and Methods:This study is a photographic, radiologic, and histological analysis of mineralized freeze-dried bone allograft healing in human sockets after mineralization at different time points. The mineralized freeze-dried bone allografts used for evaluation in this study were particulate bone graft materials in maxillary or mandibular extraction sockets. Patient selection was random, based on the following time periods: 6 months, 2 years, 5 years, 7 years, 10 years and 15 years. No block bone grafts were evaluated. Results:No resorption of cadaver bone graft particles was found at any time point. No osteoclasts were found in any of the histology at any time point. At different time points from 6 months through 15 years, mineralized freeze-dried bone allograft particles were found to be exfoliated out of the alveolar crest as a result of the formation of a hypervascular zone surrounding the grafted site. The embedded graft particles remain embedded in sclerotic bone until the particles reach the alveolar crest at which time the sclerotic bone and graft particles break up and are released into the gingiva. All histologic samples from 6 months to 15 years contained residual graft particles. The sclerotic bone formed around graft particles did not integrate to the graft particles or the implant surface. Conclusions:Mineralized freeze-dried bone allograft particles are not resorbed after mineralization. A hypervascular zone forms around the grafted site and exfoliates the bone graft particles into the gingiva. The mineralization process produces sclerotic bone which never remodels into normal bone. Sclerotic bone covers but does not integrate to the retained bone graft particles or implant surface resulting in a weakened structure with an increased likelihood of bone failure and implant loss.
ARTICLE | doi:10.20944/preprints201805.0348.v1
Subject: Engineering, Mechanical Engineering Keywords: failure criteria; curauá fibers; reinforcement direction; ANOVA.
Online: 24 May 2018 (10:23:36 CEST)
Natural fibers are being increasingly used in different areas of engineering, including as composite reinforcement. Among these fibers, carauá stands out for its good mechanical properties and adherence to resin. Nevertheless, little is known about the behavior of this material in the manufacture of a composite or whether classic failure theory can be used in this case. In this context, the present study assesses the mechanical properties of two laminas made of unidirectional curauá fiber with volumetric fiber percentages of 30 % and 22 %, and compares the results with the values obtained for four failure criteria reported in the literature, using analysis of variance (ANOVA). To that end, tensile tests were conducted in the direction of the fiber and at other loading angles, in addition to iosipescu shear tests. The results show that the maximum stress criterion does not represent the failure behavior of these materials and that the best was the Hashin criterion.
ARTICLE | doi:10.20944/preprints201705.0155.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: single fiber; cutting; fracture morphology; failure mechanism
Online: 22 May 2017 (05:29:48 CEST)
The present study investigates the failure mechanisms of industrial fiber materials, using a custom designed fiber cutting performance test bench. The fracture morphologies of single PA6 fibers are examined by scanning electron microscopy. The analysis reveals that fiber cutting can be distinguished according to four distinct stages of fiber failure represented by shearing, cutting, brittle fracture, and tensile failure, which are the result of different mechanisms active during the processes of crack initiation, extension and fracture. The results of fractographic analysis are further verified by an analysis of the blade assembly speed with respect to time over the entire fracture failure process based on high-speed camera data. The results of fractographic analysis and blade assembly speed are fully consistent.
CASE REPORT | doi:10.20944/preprints202311.1692.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: mavacamten; cardiac myosin inhibitor; hypertrophic cardiomyopathy; heart failure
Online: 27 November 2023 (11:50:17 CET)
We describe real-world use of mavacamten in 50 patients with oHCM. Consistent with EXPLORER-HCM and VALOR-HCM, we report significant improvement in wall thickness, mitral regurgitation, left ventricular outflow tract obstruction and NYHA class. Moreover, in our center’s experience, neither arrhythmia burden, nor contractility have worsened in the vast majority of patients: We note a clinically insignificant mean decrease in left ventricular ejection fraction (LVEF), with only two patients requiring temporary mavacamten discontinuance for LVEF < 50%. Adverse events were rare, unrelated to mavacamten itself, and seen solely in patients with disease too advanced to have been represented in clinical trials. Our multidisciplinary pathway enabled us to provide a large number of patients with a novel closely-monitored therapeutic within just a few months of commercial availability. These data lead us to conclude that mavacamten, as a first-in-class cardiac myosin inhibitor, is safe and efficacious in real-world settings.
ARTICLE | doi:10.20944/preprints202311.1200.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: spinal fusion; mechanical failure; risk factor; spine arthrodesis
Online: 22 November 2023 (15:17:49 CET)
PURPOSE: The aim of this study was to identify the incidence of early mechanical failure in the first post-surgical year in patients who had undergone spinal surgery, and to assess the related risk factors. METHODS: Retrospective observational study of a prognostic cohort was conducted at an orthopaedic hospital, examining all patients with spine degenerative disease who consecutively underwent arthrodesis surgery between March 2018 and March 2019. The incidence of postoperative mechanical failure during the first year was calculated as primary outcome; the time between the date of the implant surgery and diagnosis of the mechanical failure was calculated as secondary outcome. RESULTS: A total of 237 patients were identified for statistical analysis. The median age of the group of patients was 47 years (IQR of 44), and 66.6% were female. The incidence of mechanical failure in the first postoperative year was 5.1% overall with 12 events and the median time between surgery and the need for revision surgery was 5 months (IQR=7.75). ASA score (OR= 2,39; p=0.134), duration of the surgical procedure (OR=1,27; p=0,006) and inability to walk at discharge (OR=7,86; p=0,072) were independent risk of factor associated with the mechanical failure. CONCLUSION: Higher ASA score and longer duration of surgery are risk factors for mechanical failure in the first year in patients who had undergone spinal surgery and must be carefully considered when planning spinal surgery. During hospitalization, recovery of ambulation must be encouraged to prevent mechanical failure. All these factors are useful in identifying patients with a closer follow-up is needed.
ARTICLE | doi:10.20944/preprints202311.0159.v1
Subject: Medicine And Pharmacology, Emergency Medicine Keywords: Heart Failure; older adults; ultrasound; outcomes; pleural effusion
Online: 2 November 2023 (10:31:43 CET)
The decompensation trajectory check is a basic step to assess the clinical course and to plan future therapy in hospitalized patients with acute heart failure (ADHF). Due to the atypical presentation and clinical complexity, trajectory checks can be challenging in the oldest old patients with acute HF. Point of care ultrasound (POCUS) proved to be helpful in the clinical decision-making of patients with dyspnea, but no study has attempted to verify its effectiveness in predicting determinants of HF in-hospital worsening. In this single-center prospective study, we consecutively enrolled patients aged 75 or older hospitalized with acutely decompensated HF in a tertiary care hospital. All the patients underwent complete clinical examination, blood tests, and POCUS including Lung Ultrasound, Focused Cardiac Ultrasound, Pleural Effusion score (PEFs), and Inferior Vena Cava (IVC) assessment. Out of 184 patients hospitalized with ADHF enrolled in the study, sixty experienced HF in-hospital worsening. No differences were found among patients with HF worsening and controls in terms of age, gender, frailty, and left ventricular ejection fraction. By multivariable logistic analysis, total PEFs [aOR: 1.15 (CI95% 1.02– 1.33), p = 0.043], and IVC collapsibility [aOR: 0.90 (CI95% 0.83 – 0.95), p = 0.039] emerged as independent predictors of acute HF worsening after extensive adjustment for potential confounders.
ARTICLE | doi:10.20944/preprints202310.0155.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Zirconia, Glass-Ceramic; Crown; Failure Load; Yttria Concentration.
Online: 3 October 2023 (14:36:51 CEST)
The objective was to compare the failure loads of glass ceramic, and polymer crowns against yttria-partially stabilized zirconia (Y-PSZ) crowns with varying yttria concentrations. Monolithic crowns of zirconia (Cercon XT, Katana UTML, BruxZir Anterior), glass ceramic (Celtra press, IPS e.max press, Lisi press), and polymeric materials (Trilor, Juvora, Pekkton) were fabricated and cemented to epoxy abutments. The total number of specimens was 135 for crowns and 135 for discs (15 specimens per material type and design). A universal testing machine was used to perform compressive loading of all crowns to failure with a steel hemisphere along the longitudinal axis of the abutments. Energy dispersive spectroscopy (EDS) was used to identify the concentration (mol% yttria-partially stabilized zirconia) for each zirconia brand. The data were analyzed using a generalized linear model and regression analysis. The results revealed significant differences (P < .05) in mean failure loads for different crown materials: Trilor (6811 ± 960 N) > Juvora (5215 ± 151 N) > Cercon (4260 ± 520 N) = BruxZir (4186 ± 269 N) = e.max (3981 ± 384 N) > Katana (3195 ± 350 N) = Lisi (3173 ± 234 N) = Pekkton (3105 ± 398 N) > Celtra (2696 ± 393 N). EDS showed that the zirconia materials contained yttria at different concentrations (BruxZir = 5Y-PSZ, Cercon = 4Y-PSZ, Katana = 3Y-PSZ). The yttria concentration had a significant effect on the failure load of the Katana (3Y-PSZ) crowns, which revealed lower failure loads than the Cercon (4Y-PSZ) and BruxZir (5Y-PSZ) crowns. New zirconia materials are provided with different yttria concentrations (3Y-, 4Y-, and 5Y-PSZ). Since a higher yttria concentration increases the translucency, clinicians should be aware that 4-5 wt% yttria-partially stabilized zirconia materials provide comparable or higher mechanical properties than e. max glass ceramic for dental application of crowns.
ARTICLE | doi:10.20944/preprints202308.1262.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: atrial fibrillation; gender; electrical cardioversion; heart failure; mortality
Online: 17 August 2023 (07:15:22 CEST)
Background: There is limited data on gender-based differences in atrial fibrillation (AF) treatment and prognosis. Our aim was to examine gender-related differences in medical attention in emergency department (ED) and follow-up (FU) among patients diagnosed with an AF episode and to determine whether there are gender-related differences in clinical characteristics, therapeutic strategies and long-term adverse events in this population. Methods: We performed a retrospective observational study of patients who presented to a tertiary hospital ER for AF from 2010-2015, with a minimum FU of one year. Data on medical attention received, mortality and other adverse outcomes were collected and analyzed. Results: Among the 2 013 patients selected, 1232 (60%) was female. Women were less likely than men to be evaluated by a cardiologist during the ED visit (11.5% vs. 16.6%, p=0.001) and were less likely to be admitted (5.9% vs. 9.5%, p<0.05). Electrical cardioversion was performed more frequently in men, both during the first episode (3.4% vs. 1.2%, p=0.001) and during FU (15.9% vs. 10.6%, p<0.001), in spite of a lower AF recurrence rate in women (9.9% vs 18.1%). During FU, women had more hospitalizations for heart failure (26.2% vs. 16.1%, p<0.001). Conclusions: In patients with AF, although no gender differences in mortality, there were significant differences in clinical outcomes, medical attention received, and therapeutic strategies. Women underwent fewer attempts at cardioversion, had a lower probability of being evaluated by cardiologists and showed a higher probability of hospitalization for heart failure. Being alert to these iniquities should facilitate to adopt measures to correct them.
ARTICLE | doi:10.20944/preprints202307.2096.v1
Subject: Biology And Life Sciences, Virology Keywords: Cat; FIV; lentivirus; FAIDS; lymphoma; chronic renal failure
Online: 31 July 2023 (10:29:19 CEST)
Feline immunodeficiency virus (FIV) is a lentivirus in the family Retroviridae that infects domestic cats resulting in an immunodeficiency disease featuring a progressive and profound decline in multiple sets of peripheral lymphocytes. Despite compelling evidence of FIV-associated immunopathology, there are conflicting data concerning the clinical effects of FIV infection on host morbidity and mortality. To explore FIV-associated immunopathogenesis and clinical disease, we experimentally inoculated a cohort of 4 specific pathogen free kittens with a biological isolate of FIV clade C and continuously monitored these animals along with 2 uninfected control animals for more than 13 years, from the time of inoculation to the humane euthanasia endpoint. Here we report the results obtained during the late asymptomatic and terminal phases of FIV infection in this group of experimentally FIV-infected cats.
REVIEW | doi:10.20944/preprints202307.1285.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Extracellular vesicles; MicroRNAs; Sorting mechanism; Biomarkers; Heart failure
Online: 20 July 2023 (02:49:03 CEST)
Extracellular vesicles (EVs) are emerging mediators of intracellular and inter-organ communications in cardiovascular diseases (CVDs), especially in the pathogenesis of heart failure through the transference of EV-containing bioactive substances. microRNAs (miRNAs) are contained in EV cargo and are involved in the progression of heart failure. Over the past several years, a growing body of evidence has suggested that the biogenesis of miRNAs and EVs are tightly regulated, and the sorting of miRNAs into EVs is highly selective and tightly controlled. Extracellular miRNAs, in particular circulating EV-miRNAs, have shown promising potential as prognostic and diagnostic biomarkers for heart failure and as therapeutic targets. In this review, we summarize the latest progress concerning the role of EV-miRNAs in HF and their application in a therapeutic strategy development for heart failure.
REVIEW | doi:10.20944/preprints202306.0991.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: exercise; diabetes; obesity; hypertension; ventricular remodeling; heart failure
Online: 14 June 2023 (05:34:21 CEST)
Left ventricular (LV) remodeling is a dynamic process which is characterized by abnormal LV wall thickness and altered myocardial geometry, and it is considered as a negative prognostic factor in both heart failure with reduced eject fraction (HFrEF) and heart failure with preserved eject fraction (HFpEF). Hypertension, type 2 diabetes (T2D) and obesity are strongly correlated with the development and the progression of LV remodeling, LV hypertrophy and LV systolic and/or diastolic dysfunction. Indeed, the beneficial impact of exercise training on primary and secondary prevention of cardiovascular disease (CVD) has been well-established. Recent studies highlight that exercise training enhances functional capacity, muscle strength and endurance, cardiac function and cardiac-related biomarkers, among patients with established coronary artery disease (CAD) or HF, thus improving substantially their cardiovascular prognosis, survival rates and needs for rehospitalization. Therefore, in this review article, we discuss the evidence of LV remodeling in patients with cardiometabolic risk factors, such as hypertension, T2D, obesity, and also highlight the current studies evaluating the effect of exercise training on LV remodeling in these patients.
REVIEW | doi:10.20944/preprints202305.0149.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Acute liver failure; viral hepatitis; sub-Saharan Africa
Online: 3 May 2023 (12:40:38 CEST)
Though there has been a decline in the number of new cases of viral hepatitis-induced acute liver failure in Europe and the United States of America, viral hepatitis still remains the leading cause of acute liver failure in Asia-Pacific and South America. However, the epidemiology of viral-hepatitis-induced acute liver failure in sub-Saharan Africa-the world epicenter of viral hepatitis-is unclear. The aim of this review was to collate data on the incidence, prevalence, specific etiologic agents, features/diagnosis, treatment and prognosis of viral-induced acute liver failure in sub-Saharan Africa. One hundred and forty-seven cases of viral-induced acute liver failure were recorded in 11 studies conducted in six countries between 1981-2020. Etiological agents were: Hepatitis viruses A, B, C, and E, as well as Adenovirus, Enterovirus, Parvovirus, Herpes Simplex Virus (HSV) and EBV. HAV was the most frequent in paediatric subjects: (11/16) 69% and (19/30) 63%. HBV was the only etiological agent in the study that only included adults. HEV (genotype 2 in one study) contracted amidst hepatitis E outbreaks was the most commonly reported cause of ALF in pregnant women. Treatment was mainly supportive, and liver transplantation reported only in South Africa. Where reported, case fatality rates were high. In conclusion, viral-hepatitis induced acute liver failure is largely understudied in sub-Saharan Africa. The few available data are consistent with literature from the other parts of the world regarding aetiologic agents. Liver transplantation is not available in most sub-Saharan African countries, and short-term case fatality rates of individuals with acute liver failure could outstrip current rates from the other world regions.
ARTICLE | doi:10.20944/preprints202304.1085.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: SARS-CoV-2; pandemic; children infection; respiratory failure
Online: 28 April 2023 (03:02:24 CEST)
Background: Children suffering from COVID-19 constitute about 10% of the entire population infected with the virus. In most of them, we observe asymptomatic or mild course; however, about 1% of affected children require a stay in the pediatric intensive care unit (PICU) due to the severe life-threatening course. The risk of respiratory failure, as in adults, is associated with the coexistence of concomitant diseases. The aim of our study was to analyze patients admitted to PICUs due to severe course of SARS-CoV-19 infection. Methods: A retrospective multi-center study, the analysis covered all children with a confirmed diagnosis of SARS-CoV-2 virus infection, who were admitted to PICUs, in the period from November 2020 to August 2021. We studied epidemiological and laboratory parameters, and the endpoint – survival or death. Results: The study analyzed 45 patients (0.075% of all children hospitalized in Poland due to COVID-19 at that time). Mortality calculated in the entire study group was 40% (n=18). Statistically significant differences between the compared groups (survived and died) concerned the parameters of the respiratory system, Lung Injury Score and Pediatric Sequential Organ Failure Assessment . A significant correlation between disease severity and the patient's prognosis was shown by the liver function parameter AST (p=0.028). Analyzing patients requiring mechanical ventilation and assuming survival as the primary outcome, a significantly higher oxygen index on the first day of hospitalization, lower pSOFA scores and lower AST levels (p: 0.007; 0.043; 0.020; 0.005; 0.039, respectively) were found. Conclusions: As in adults, children with comorbidities are most frequently at risk of severe SARS-CoV-2 infection. Increasing symptoms of respiratory failure, the need for mechanical ventilation and persistently high values of aspartate aminotransferase are indicators of poor prognosis.
ARTICLE | doi:10.20944/preprints202304.0797.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Heart failure; Malnutrition; Exercise; Amino-acids; mTOR; Deptor
Online: 23 April 2023 (08:45:26 CEST)
Malnutrition, clinically evident primarily with sarcopenia, is present in more than 50% of CHF patients and is an independent factor of morbidity and mortality. Several pathophysiological mechanisms, such as reduced appetite, metabolic imbalance and altered protein synthesis/degradation rate, due to the blood increase of hypercatabolic molecules, have been proposed to explain this phenomenon. Nutritional supplementation with proteins, amino acids and vitamins have all been used to treat malnutrition, acting through mTOR stimulation. However, the success and efficacy of these procedures are often contradictory and not conclusive. Interestingly, data on exercise training show that exercise reduces mortality and increase functional capacity, although it also increases energy expenditure and nitrogen providing substrate needs. Therefore, this paper discusses the molecular mechanisms of integrated nutritional approaches that would stimulate metabolic anabolic pathways. Pivotal in our opinion, is the relationship between exercise and Deptor, a subunit of the mTOR complex. Consequently, we propose a combination of personalized and integrate nutritional supplementation as well as exercise to treat malnutrition and related anthropometric and functional CHF-related disorders.
REVIEW | doi:10.20944/preprints202304.0422.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; kidney disease; multidisciplinary assessment; personalized treatment
Online: 17 April 2023 (07:27:32 CEST)
CKD in HF patients is very common condition, their dysfunction is closely linked and influence each other, so their management required multidisciplinary and personalized approaches. The diagnosis of HF and CDK relies on signs and symptoms. Several tools, such as blood-based biomarkers and echography help us to clarify and discriminate the main characteristics of these patients. Evidence in improving survival due to new drug-employment in HF, has increasingly challenged physicians to manage patients with multiple diseases, especially in patients with CKD. The difficulty is in the safe administration of these drugs in patients with HF and CKD. Knowing up to which values of creatinine or renal clearance any drug can be administered is fundamental. We wanted to summarize, on this sizable and complex topic, the experiences of various prior study to get clearer ideas and a more precise reference about the assessment and management of HF and CKD.
ARTICLE | doi:10.20944/preprints202112.0350.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: HMGB1; trauma; hemorrhagic shock; inflammation; multiple organ failure
Online: 22 December 2021 (10:36:56 CET)
Several preclinical and clinical reports have demonstrated that levels of circulating high mobility group box 1 protein (HMGB1) are increased early after trauma and are associated with systemic inflammation and clinical outcomes. However, the mechanisms of the interaction between HMGB1 and inflammatory mediators that lead to the development of remote organ damage after trauma remain obscure. HMGB1 and inflammatory mediators were analyzed in plasma from 54 combat casualties, collected on admission to a military hospital in Iraq, and at 8 and 24 hours after admission. Forty-five (83%) of these patients had traumatic brain injury (TBI). Nine healthy volunteers were enrolled as controls. HMGB1 plasma levels were significantly increased in the first 8 hours after admission, and were found to be associated with systemic inflammatory responses, injury severity score, and presence of TBI. These data provided the rationale for designing experiments in rats subjected to blast injury and hemorrhage, to explore the effect of HMGB1 inhibition by CX-01. Animals were cannulated, then recovered for 5-7 days before blast injury in a shock tube and volume-controlled hemorrhage. Blast injury and hemorrhage induced an early increase in HMGB1 plasma levels that coincided with severity of tissue damage and mortality. CX-01 inhibited systemic HMGB1 release, decreased local and systemic inflammatory responses, significantly reduced tissue and organ damage, and tended to increase survival. These data suggest that CX-01 has potential as an adjuvant treatment for traumatic hemorrhage.
ARTICLE | doi:10.20944/preprints202109.0110.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cardiac fibroblasts; sex-specific; estrogen; fibrosis; heart failure
Online: 6 September 2021 (17:24:51 CEST)
Several studies have demonstrated estrogen’s cardioprotective abilities in decreasing the fibrotic response of cardiac fibroblasts (CFs). However, the majority of these studies are not sex-specific, and those at the cellular level utilize tissue culture plastic, a substrate that has a stiffness much higher than physiological conditions. Understanding the intrinsic differences between male and female CFs under more physiologically “healthy” conditions will help to elucidate the divergences in their complex signaling networks. We aimed to do this by conducting sex-disaggregated analysis of changes in cellular morphology and relative concentrations of profibrotic signaling proteins in CFs cultured on 8kPa stiffness plates with and without 17-β estradiol (E2). Cyclic immunofluorescent analysis indicated that there is a negligible change in cellular morphology due to sex and E2 treatment and that the differences between male and female CFs are occurring at a biochemical rather than structural level. Several proteins corresponding to profibrotic activity had various sex-specific responses with and without E2 treatment. Single-cell correlation analysis exhibited varied protein-protein interaction across experimental conditions. These findings demonstrate the need for further research into the dimorphisms of male and female CFs to develop better tailored, sex-informed prevention and treatment interventions of cardiac fibrosis.
ARTICLE | doi:10.20944/preprints202103.0655.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondria; Ca2+ handling; heart failure; CaMKII; cardiomyocyte hypertrophy
Online: 26 March 2021 (10:41:00 CET)
Background : ATPase inhibitor factor-1 (IF1) preserves cellular ATP under conditions of respiratory collapse, yet the function of IF1 under normal respiring conditions is unresolved. We tested the hypothesis that IF1 promotes mitochondrial dysfunction and pathological cardiomyocyte hypertrophy in the context of heart failure (HF). Methods and results Cardiac expression of IF1 was increased in mice and in humans with HF, downstream of neurohumoral signaling pathways and in patterns that resembled the fetal-like gene program. Adenoviral expression of wild type IF1 in primary cardiomyocytes resulted in pathological hypertrophy and metabolic remodeling as evidenced by enhanced mitochondrial oxidative stress, reduced mitochondrial respiratory capacity, and the augmentation of extra-mitochondrial glycolysis. Similar perturbations were observed with an IF1 mutant incapable of binding to ATP-synthase (E55A mutation), indication that these effects occurred independent of binding to ATP synthase. Instead, IF1 promoted mitochondrial fragmentation and compromised mitochondrial Ca2+ handling, which resulted in sarcoplasmic reticulum Ca2+ overloading. The effects of IF1 on Ca2+ handling were associated with the cytosolic activation of CaMKII and inhibition of CaMKII or co-expression of catalytically dead CaMKIIδC was sufficient to prevent IF-1 induced pathological hypertrophy. Conclusions IF1 represents a novel member of the fetal-like gene program that contributes to mitochondrial dysfunction and pathological cardiac remodeling in HF. Furthermore, we present evidence for a novel, ATP-synthase independent, role for IF1 in mitochondrial Ca2+ handling and mitochondrial- to nuclear crosstalk involving CaMKII.
ARTICLE | doi:10.20944/preprints202005.0483.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Lung CT; imaging; COVID-19; Pneumonia; Heart Failure
Online: 31 May 2020 (16:49:04 CEST)
Background: Lung CT provides an effective modality to evaluate patients with suspected COVID-19. However, overlapping imaging findings with cardiogenic pulmonary oedema have been reported. Reports comparing lung CT features of these diseases have not been elaborated. Thus, we aimed to investigate these gaps in the knowledge regarding low-dose lung CT features of patients with COVID-19 pneumonia with those with acute heart failure (HF). Methods: This retrospective analysis enrolled hospitalized patients with COVID-19 (n=10) and acute heart failure (n=9) that exclusively underwent low-dose lung CT scans within 24-hours of admission. Clinical and lung CT characteristics were collected and analysed. Results: Ground-glass-opacities (GGO) appearance has been recorded in all subjects in HF and COVID-19 group. There was no significant statistical difference between the two groups for rounded morphology, consolidation, crazy paving pattern, lesion distribution, parenchymal band (P> 0.05). However, diffuse lesions were more frequent in HF cases (55.6% vs. 0%) than in COVID-19 pneumonia, which had predominantly multifocal pattern. Notably, CT images in HF patients were more likely to have signs of interstitial tissue thickening such as the interlobular septums, fissures and peribronchovascular interstitium (55.6% vs 0%, 88.9% vs 20% and 44.4% vs 0%,respectively), as well as cardiomegaly (77.8% vs 0%), increased artery to bronchus ratio (55.6% vs 0%), and pleural effusions (77.8% vs 0%). Conclusions: Major overlaps of lung CT imaging features existed between COVID-19 pneumonia and acute HF cases. However, signs of fluid redistribution are clues that favour HF over COVID-19 pneumonia.
ARTICLE | doi:10.20944/preprints201901.0091.v1
Subject: Engineering, Civil Engineering Keywords: Acoustic emissions, fracture process, failure prediction, q-statistics
Online: 9 January 2019 (16:35:10 CET)
In this paper we present experimental results concerning Acoustic Emission (AE) recorded during cyclic compression tests on two different kinds of brittle building materials, namely concrete and basalt. The AE inter-event times were investigated through a non-extensive statistical mechanics analysis which shows that their decumulative probability distributions follow q-exponential laws. The entropic index q and the relaxation parameter q 1=Tq, obtained by fitting the experimental data, exhibit systematic changes during the various stages of the failure process, namely (q; Tq) linearly align. The Tq = 0 point corresponds to the macroscopic breakdown of the material. The slope, including its sign, of the linear alignment appears to depend on the chemical and mechanical properties of the sample. These results provide an insight on the warning signs of the incipient failure of building materials and could therefore be used in monitoring the health of existing structures such as buildings and bridges.
ARTICLE | doi:10.20944/preprints201808.0099.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: premature ovarian failure (POF); PBMC, chemotherapy; cancer; ovary
Online: 6 August 2018 (07:56:50 CEST)
Cancer treatment with specific chemotherapeutic agents has been well documented to have an adverse impact on female fertility leading to premature ovarian failure (POF). The objective of this study was to investigate if chemotherapeutic induced POF can be reversed with an infusion of autologous nucleated peripheral blood cells (PBMC). To reach our goal, mice were treated with a single intraperitoneal injections of busulfan and cyclophosphamide to induce POF. This was followed by transfusion of PBMC. The ovarian morphology and functional parameters were monitored by radioimmunoassay, real-time PCR, immunofluorescence and immunohistochemistry analysis. Our study showed that chemotherapy (CTX) protracted estrous cycle period and repressed E2 production. CTX decreased the expressions of steroidogenesis markers- CYP-17 synthesis, StAR and Connexin-43 protein expression from the ovarian follicles. We also observed reduced numbers and sizes of the primordial and primary follicles in CTX-treated mice compared to untreated controls (P < 0.05). When both CTX and untreated –control groups were stimulated with gonadotrophin, the control group produced ten times more ova than the CTX group. Finally, the treatment of premature ovarian failure induced by CTX with autologous PBMC transfusion resulted in over-expression and a statistically significant increase in several stem cell markers and restoration of fertility. Infusion with PBMC in CTX further decreased the estrous cycle length by 2.5 times (P < 0.01). We found that transfusion of autologous PBMC to mice with chemotherapy induced POF was very effective at restoring fertility. These results are similar to other studies using bone marrow derived mesenchymal stem cells.
REVIEW | doi:10.20944/preprints202311.0761.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: photovoltaics; reliability; degradation; failure mechanism; solar cells; solar modules
Online: 13 November 2023 (10:16:23 CET)
With the global increase of photovoltaic (PV) modules deployment in recent years, the need to explore and realize their reported failure mechanisms has become crucial. Despite PV modules being considered reliable devices, failures and extreme degradations often occur. Some degradations and failures can be minor and cause no critical harm if within the expected range. Others, may start mildly and then deteriorate faster to become catastrophic, especially in harsh environments. This paper conducts a state-of-the-art literature review to scan PV failures, types, and their root cause based on PV’s constructed components (from protective glass to junction-box). It outlines the hazardous consequences beyond PV module failures, describing what harm they can bring to the PV system. As we delve into the literature, it becomes clear that every component is vulnerable to certain types of failures; some can deteriorate within themselves, and others infect further PV components resulting in emerging more severe failures. In the end, the review briefly summarises PV failure detection techniques, emphasising electrical characterization techniques, and disclosing the need to engage more electrical parameters. Most importantly, this review can prepare the stage for the PV research community to identify the most prevalent degradation processes. This, in turn, encourages researchers to investigate them throughout modelling and experimental studies to forecast them at the early onset in order to protect the PV systems from hazardous malfunctions.
CASE REPORT | doi:10.20944/preprints202309.1501.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: severe malaria; Plasmodium falciparum; chemoprophylaxis failure; oral artemether-lumefantrine
Online: 22 September 2023 (02:58:59 CEST)
This case report presents a critical clinical scenario involving a 55-year-old patient who developed severe Plasmodium falciparum malaria with renal complications despite receiving doxycycline prophylaxis while travelling in a malaria-endemic region. The case emphasizes the potential failure of doxycycline prophylaxis and highlights the importance of considering malaria in patients with a history of travel to endemic areas, even if they have adhered to prophylactic treatment. The patient's clinical presentation included fever, extreme fatigue, and loss of consciousness, leading to hospitalization. Laboratory findings revealed severe anaemia, elevated liver enzymes, and impaired renal function, consistent with the criteria for severe malaria. The diagnosis was confirmed by the presence of Plasmodium falciparum parasites on blood smears. Due to limited access to parenteral antimalarial medications, the patient received oral artemether-lumefantrine, resulting in clinical improvement. Supportive care and dialysis played a vital role in the patient's recovery. This case report underscores the need for increased awareness of prophylaxis failure, the challenges of managing severe malaria in non-endemic countries, and the importance of timely and appropriate interventions to improve outcomes in severe malaria cases, particularly those with renal involvement. Further research is warranted to evaluate alternative preventive strategies in regions with drug-resistant malaria strains.
ARTICLE | doi:10.20944/preprints202308.1669.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: atrial fibrillation; heart failure; rhythm strategy; catheter ablation; snapshot
Online: 25 August 2023 (02:48:47 CEST)
Background and Objectives: Proper use of oral anticoagulants is crucial in the management of non-valvular atrial fibrillation (AF) patients. Left atrial appendage closure (LAAC) may be considered for stroke prevention in patients with AF and contraindications for long-term anticoagulant treatment. We aimed to assess the anticoagulation status and LAAC indications in patients with AF from HECMOS (Hellenic Cardiorenal Morbidity Snapshot) survey. Materials and Methods: HECMOS was a nationwide snapshot survey of cardiorenal morbidity in hospitalized cardiology patients. HECMOS used an electronic platform to collect demographic and clinically relevant information from all patients hospitalized on March 3, 2022, in 55 different cardiology departments. In this substudy, we included patients with known AF without mechanical prosthetic valves and moderate to severe mitral valve stenosis. Patients with prior stroke, previous major bleeding, poor adherence to anticoagulants, and end-stage renal disease were considered candidates for LAAC. Results: Two hundred fifty-six patients (mean age 76.6±11.7, 148 males) were included in our analysis. Most of them (n=159; 62%) suffered from persistent AF. Mean CHA2DS2-VASc score was 4.28±1.7, while mean HAS-BLED score was 1.47±0.9. Three out of 3 patients with a CHA2DS2-VASc 0 or 1 (female) received improperly anticoagulants. Sixteen out of 18 patients with a CHA2DS2-VASc 1 or 2 (female) received anticoagulants. Thirty-three out of 235 patients with a CHA2DS2-VASc > 1 or 2 (for female) did not receive improperly anticoagulants. Among 221 under anticoagulant therapy, 191 (86.4%) received non-vitamin K antagonist oral anticoagulants (NOACs) and 30 (13.6%) received vitamin K antagonists. Relative indications for LAAC were present in 64 patients with NVAF (60 had only one risk factor and 2 had two concurrent risk factors). In detail, 36 had a prior stroke, 17 patients had a history of major bleeding, 15 patients reported poor or no adherence to the anticoagulant therapy and 5 had eGFR< 15 ml/min/1.73m2. Moreover, 33 had a HAS-BLED score ≥3. No LAAC treatment was recorded. Conclusions: Anticoagulation status was nearly optimal in a high thromboembolic risk population of cardiology patients, mainly treated with NOACs. One out of four AF patients should be screened for LAAC.
REVIEW | doi:10.20944/preprints202308.1645.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: dilated cardiomyopathy; heart failure; cardiac device therapy; genetic analysis
Online: 23 August 2023 (09:20:43 CEST)
Dilated cardiomyopathy (DCM) is a common form of cardiomyopathy, characterized by ventricular chamber dilatation and systolic dysfunction, in the absence of coronary artery disease, arterial hypertension, valvular or congenital diseases. DCM is a heterogeneous group of disorders of the myocardium caused by genetic factors, environmental factors, or a combination of both. DCM affects mainly men aged between 20 and 50 years, being considered one of the main causes of heart failure (HF) and the main indication for heart transplantation. Guideline-based HF treatment is the mainstay of management for patients with DCM. In recent years, gene therapy and induced pluripotent stem cells have become promising strategies. In this review, we summarize the relevant clinical issues, and current treatment of DCM patients, including the role of genetic evaluation.
REVIEW | doi:10.20944/preprints202307.0090.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Sacubitril-valsartan; heart failure; ejection fraction and cardiovascular disease
Online: 3 July 2023 (13:25:11 CEST)
Background: The 2021 “Universal Definition of Heart Failure (HF)” Proposed the following left ventricle ejection (LVEF) phenotype classification: ≤40%; HF with intermediate LVEF: between 41-49% and HF with preserved LVEF: ≥50%. LVEF represents the percentage of left ventricular ejected volume in each cardiac cycle and Cut-points considered statistically normal are: ≥52% in men and ≥54% in women. The prevalence HFpEF is of 35-60% among the HF phenotypes, with a facing to increase rates in relation to HFrEF and is associated with mortality rates similar to those of HFrEF. The pathophysiology of HFpEF is based on vascular and metabolic dysfunction, therefore, there is less neurohumoral stimulation compared to HFrEF. Methodology: A systematic review was performed to report of information related to Sacubitril-valsartan and the treatment of HFrEF. Terms related to “treatment” and “brazil” were used in the databases PubMed (MEDLINE) and Scientific Electronic Library Online (SCIELO). Results: Clinical trials testing drugs that modulate the neurohumoral system in patients with HFpEF failed to demonstrate benefit in the combined endpoint of reduced mortality/hospitalization due to HF compared to placebo to date. Sacubitril-valsartan is a drug with a mechanism of action surrogate the pathophysiological concept of HFpEF, it is safe and decreased endpoints of natriuretic peptides and left atrial structure in a phase II clinical study. Conclusions: The PARAGON-HF trial demonstrated that sacubitril-valsartan reduced the primary endpoint of the study when assessed the pre-specified subgroup of LVEF≤57% and improved the secondary endpoints of performance status and renal function in the population.
ARTICLE | doi:10.20944/preprints202306.2009.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; cardiomyopathy; ischemic heart disease; prognosis; women; men
Online: 29 June 2023 (07:27:12 CEST)
Background: Limited research has explored sex-specific differences in death predictors of HF pa-tients with ischemic (iCMP) and nonischemic (niCMP) cardiomyopathy. This study assessed sex differences in niCMP and iCMP prognosis. Methods: We studied 7,487 patients with HF between February 2017 and September 2020. Clini-cal features and echocardiographic findings were collected. We used Kaplan-Meier, Cox propor-tional hazards models, and score chi-square of Cox regression to determine death predictors in women and men. Results: mean age was 64.3±14.2 years, with 4,417 (59%) males. Women with iCMP and niCMP exhibited significantly higher mean age, higher mean left ventricular ejection fraction, and smaller left ventricular diastolic diameter than men. Over 2.26 years of follow-up, 325 (14.7%) women and 420 (15.7%) men, and 211 women (24.5%) and 519 men (29.8%) died in niCMP (p=NS) and iCMP (p=0.004), respectively. Cumulative incidence of death was higher in men with iCMP (log-rank p<0.0001) but similar in niCMP. Cox regression showed chronic kidney disease, dia-betes, stroke, atrial fibrillation, age, and myocardial infarction, as main predictors of death for iCMP in women and men. Conclusion: Women exhibited a better prognosis than men in iCMP, but similar for niCMP. Nevertheless, sex was not an independent predictor of death for both CMP.
ARTICLE | doi:10.20944/preprints202306.1952.v1
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: Assisted oocyte activation; ICSI; polarization microscopy; fertilization failure; blastocyst
Online: 28 June 2023 (05:22:26 CEST)
Is there any possible synergic effect of fertility outcome between spindle view-assisted intracyto-plasmic sperm injection (SV-ICSI) with or without assisted oocyte activation (AOA) for patients with low fertilization rate history? To explore the answer, a retrospective study was held in our fertility center by reviewing patients receiving SV-ICSI during 2019/03 to 2023/06. Total 47 pa-tients were included, the fertility outcomes of intervention group (AOA-SV-ICSI, 14 patients) and control group (SV-ICSI, 33 patients), such as fertilization rate, blastocyst formation rate and clin-ical pregnancy rate, were analyzed. The blastocyst formation rate between groups was signifi-cantly higher in AOA-SV-ICSI group (p=0.020), but the fertilization rate and clinical pregnancy rate did not reach any statistical significance. This discovery of increased blastocyst formation rate in low fertilization rate patients could possibly help them in getting more usable embryos in fertility treatment.
ARTICLE | doi:10.20944/preprints202305.0440.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: hot spot; crack propagation; numerical simulation; YSZ failure; sinter
Online: 8 May 2023 (04:36:59 CEST)
On the aero-engine combustor liner, a phenomenon of overheating resembling a hot spot exists, accompanied by a preferential peeling of the YSZ thermal barrier coating that will negatively affect the service life of the component. The temperature gradient of the hot spot may affect the YSZ fracture pattern.In this paper, the morphological and property changes of YSZ sintering is investigated experimentally, and a coupled analysis of the YSZ Crack Propagation Mode under the hot spot is performed using ABAQUS. The results show that the pore fractal size D of YSZ increases by 15%. Inside the hot spot region, the coating has a shear stress of 75MPa. By inserting Cohesive units globally in the model to simulate the random crack initiation and propagation, unlike the thinning of YSZ layered peeling caused by uniform superheating, hot spot will cause the crack initiation at the tip of the pores inside the coating and the oblique propagation, eventually forming an oblique crack connection through the pores. When the temperature gradient reaches 30K/mm, the crack propagation is 40% greater than in a uniform temperature field; consequently, the YSZ in the hot spot boundary region with a greater temperature gradient results in more severe bulk peeling.
REVIEW | doi:10.20944/preprints202304.0738.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Heart failure; Sodium-glucose co-transporter; diabetes; cardiovascular outcomes.
Online: 23 April 2023 (03:13:59 CEST)
Sodium-glucose co-transporter 2 (SGLT2) inhibitors, originally used for diabetes mellitus, are gaining more popularity for other indications owing to their positive cardiovascular and renal effects. Initially, SGLT2 inhibitors were shown to reduce heart failure (HF) hospitalization and improve cardiovascular outcomes in patients with type 2 diabetes. Later, SGLT2 inhibitors were evaluated in patients with HF with reduced ejection fraction (HFREF) and had beneficial effects independent of the presence of diabetes. Recently, reduction in cardiovascular outcomes were also observed in patients with HF with preserved ejection fraction (HFPEF). SGLT2 inhibitors also reduced renal outcomes in patients with chronic kidney disease. Overall, these drugs have an excellent safety profile with a negligible risk of genitourinary tract infections and ketoacidosis. In this review, we discuss the current data regarding SGLT2 inhibitors in special populations including acute myocardial infarction, acute HF, right ventricular (RV) failure, patients with left ventricular assist device (LVAD), and patients with type1 diabetes. We also discuss the potential mechanisms behind the cardiovascular benefits of these drugs.
REVIEW | doi:10.20944/preprints202211.0551.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: biomarkers; Heart failure with preserved ejection fraction; Metabolomic; microRNA
Online: 29 November 2022 (11:58:09 CET)
Heart failure with preserved ejection fraction (HFpEF) remains a poorly characterized syndrome with many dark aspects related to different patients profile, various associated risk factors and wide aetiologies. It comprises several pathophysiological pathways related to endothelial dysfunction, myocardial fibrosis, extracellular matrix deposition and high inflammatory response. Up to now, it has been described only for clinical appearance and most common associated risk factors without an effective characterization of biological processes responsible for cardiovascular deteriorations. Recent advances in laboratory and metabolomic researches showed that HFpEF appears strictly related to specific cells and molecular mechanisms dysregulation. Some biomarkers are capable to early identify these processes adding new insights into diagnosis and risk stratification. Additionally recent advances on intermediate metabolites reflecting provide relevant information on intrinsic cellular and energetic substrate alterations. The systematic combination of clinical imaging and laboratory data may lead to a precision medicine approach providing prognostic and therapeutic advantages. Current review reports traditional and emerging biomarkers recently investigated in HFpEF setting, and it purpose a new diagnostic approach based on integrative information achieved from risk factors burden, hemodynamic dysfunction and biomarkers signature partnership.
ARTICLE | doi:10.20944/preprints202111.0548.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Failure Prediction; Fault-tolerance; Cloud Computing; Artificial Intelligence; Reliability
Online: 29 November 2021 (15:39:23 CET)
Identifying and anticipating potential failures in the cloud is an effective method for increasing cloud reliability and proactive failure management. Many studies have been conducted to predict potential failure, but none have combined SMART (Self-Monitoring, Analysis, and Reporting Technology) hard drive metrics with other system metrics such as CPU utilisation. Therefore, we propose a combined metrics approach for failure prediction based on Artificial Intelligence to improve reliability. We tested over 100 cloud servers’ data and four AI algorithms: Random Forest, Gradient Boosting, Long-Short-Term Memory, and Gated Recurrent Unit. Our experimental result shows the benefits of combining metrics, outperforming state-of-the-art.
ARTICLE | doi:10.20944/preprints202110.0208.v1
Subject: Social Sciences, Education Keywords: Adaptation; Failure; Feedback; Innovation; Learning; Sanitation; Scale-up; Success
Online: 14 October 2021 (08:21:38 CEST)
Background This paper draws learnings and successes based on field implementation experience spanning four years (2016–2019) of implementing CLTS by Prince of Peace Orphans and Widows Vision, a community-based organization located in Kaberamaido district in eastern Uganda. Methods The study aimed to document, disseminate and inform from an evidence-based point of view how adaptation and collaborative engagements triggers learning from mistakes to inform iterative changes from improvements and success.This is a descriptive paper that used project documents review based on field implementation experience. Existing project reports were synthesised, collated and curated for evidence. Data were drawn from project reports and records to inform narratives in writing. Implementation of the project was executed in homogenous rural communities occupied by people of the same dialect, cultural and social settings. Results We note that success in CLTS implementation can hardly be achieved by merely following prescriptions in handbooks and guidelines but rather by devising innovative community engagement and other participatory and community-driven techniques that foster adaptive management, promote ownership, and buy-in.Having learned from our failures, we used data to inform decisions and transformatively deviated from traditional CLTS implementation and introduced high impact and innovative approaches such as the use of CLTS helpdesks and Situation room, the Pamoja approach, learning labs and iterative feedback loops, innovatively tackling slippage and carefully introducing the follow-up mandona approach. These enhanced experiential learning and ultimately resulted in sustained sanitation behaviour. Conclusions The CLTS approach as outlined in the handbook needs to be flexibly adapted to address contextual needs. Reflective and learning sessions reinforced with routine feedback loops from implementers and beneficiaries yields tremendous results, propagates experiential learning, and ultimately results in a transformative deviation from undesirable to desired sanitation behaviours. These innovative approaches once carefully blended have proved to be sustainable, are adaptable and can work in an even larger scale and in a variety of contexts.
REVIEW | doi:10.20944/preprints202011.0357.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Heart failure; dysfunctional cardiomiocytes; pathophysiological mechanisms; oxidative stress; nutraceuticals
Online: 12 November 2020 (17:25:06 CET)
Heart failure (HF) is a disease state which has been shown to affect 1-2% of the global population, being often associated with comorbidities such as diabetes, hypertension, obesity or hyperlipidaemia which increase the prevalence of the disease, the rate of hospitalization and the mortality. Although recent advances in both pharmacological and non pharmacological approaches have led to significant improvements in clinical outcomes in patients affected by HF, residual unmet needs remain. Treatment of the disease remains unclear particularly related to poorly defined strategies in the early stages of myocardial dysfunction. Nutritional support in patients developing HF and nutraceutical supplementation have recently been shown to may contribute in the protection of the failing myocardium, though their place in the treatment of HF still needs to be better clarified. In this context, the ONUS-HF working group aimed to assess the optimal nutraceutical approach to HF in the early phases of the disease in order to counteract selected pathways which are imbalanced in the failing myocardium. In particular, we reviewed several of the most relevant pathophysiological and molecular changes occurring druing the early stages of myocardial dysfunction. These include mitochondrial and sarcoplasmic reticulum stress, insufficient nitric oxide (NO) release, cardiac stem cell mobilization and imbalanced regulation of metalloproteinases. Several candidates for nutraceutical supplementation in HF, such as CoQ10, grape seed extract, Olea Europea L- related antioxidants, SGLT2 inhibitors-rich apple extract and bergamot polyphenolic fraction have been assessed for their potential contribution to cardiomyocyte prottection. This approach should define the optimal approach for more targeted and successful strategies based on the use of nutraceuticals in HF to be confirmed by means of clinical trials exploring efficacy and safety of these compounds.
BRIEF REPORT | doi:10.20944/preprints201910.0077.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; angiogenesis; angiopoietin-1; angiopoietin-2; cardiac fibrosis
Online: 8 October 2019 (05:59:11 CEST)
Background and Objectives: Ischemic and idiopathic heart failure are two different etiologies, however reactive cardiac fibrosis together with impaired vasculogenesis has been described in both of them. Implication of main proangiogenic factors as: angiogenin, agiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) has been described mainly in experimental models of heart failure. However, differences in molecular pathways between these cardiomyopathies are still under investigation. In this short communication we aimed to evaluate and compare the expression of pro-angiogenic molecules in the heart tissue of patients with advanced chronic heart failure (CHF) of ischemic and idiopathic etiology. Methods and Results: Heart tissue from left ventricular walls was obtained at transplantation from ischemic heart disease (IHD), idiopathic cardiomyopathy (ICM) patients. Tissue samples were examined using immunohistochemistry for angiogenic molecules. Immunopositivity (I-pos) for angiopoietin-1 was mainly observed in the cardiomyocytes, while I-pos for Ang-2 and Tie-2 receptor mainly in endothelial cells. Procollagen-I (PICP), angiogenin, Ang-1, Tie-2 receptor, were similarly expressed in IHD and ICM patients. In contrast, endothelial immunopositivity for Ang-2 was higher in IHD samples compared to ICM (p=0.03). Conclusions: Ang-2 expression is different in heart tissue of ICM and ICM patients and distribution of Ang-1 and angiogenin is higher in cardiomyocytes, whereas Ang-2 higher in endothelial cells, suggesting a different pattern of angiogenic stimulation, or at least of altered endothelial integrity. This data may serve for further studies investigating angiogenesis signaling pathways and in HF of different etiology.
ARTICLE | doi:10.20944/preprints201901.0183.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: failure mode; impulse current; microstructure; multiple lightning; ZnO varistors
Online: 18 January 2019 (11:08:51 CET)
In this study, in order to explore the failure mode of ZnO varistors under multiple lightning stroke, a 5-pulse 8/20 μs nominal lightning current with pulse intervals of 50 ms was applied to the ZnO varistors. Scanning electron microscopy (SEM) and X-ray diffractometry (XRD) were used to analyze the microstructure of the material. The failure processes of ZnO varistors caused by multiple lightning impulse current were described. The performance changes of ZnO varistors after multiple lightning impulses were analyzed from macro and micro perspectives. According to the results of this study’s experiments, the macroscopic failure mode of the ZnO varistors after multiple lightning impulse was that the electrical parameters deteriorate rapidly with the increase of the number of impulse groups, and finally destroyed by side-corner cracking. The microstructural examination indicated that after the multiple lightning strokes, the proportion of Bi in the several crystal phases had been converted, the grain size of ZnO varistors became smaller, and the white intergranular phase (Bi-rich grain boundary layer) increased significantly. The failure mechanism was thermal damage and grain boundary structure damage caused by temperature gradient thermal stress generated by multiple lightning current.
ARTICLE | doi:10.20944/preprints201810.0438.v1
Subject: Engineering, Mechanical Engineering Keywords: wind turbines; reliability; criticality analysis; failure; down times; availability
Online: 19 October 2018 (07:50:09 CEST)
Failure of wind turbines is a multi-faceted problem and its monetary impact is often unpredicted. In this study, we present a novel application of survival analysis on wind turbine reliability performance that includes accounting of previous failures and history of scheduled maintenance. We investigate the operational, climatic and geographical factors which affect wind turbine failures and model the risk rate of wind turbine failures based on data from 109 turbines in Germany operating during a period of 19 years. Our analysis showed that adequately scheduled maintenance can increase the survivorship of wind turbine systems and electric subsystems up to 2.8 and 3.8 times, respectively compared to the ones without scheduled maintenance. Geared-drive wind turbines and their electrical systems were observed to have 1.2- and 1.4-times higher survivorship, respectively, compared to direct-drive turbines and their electrical systems. It is also found that survivorship of frequently-failed wind turbine components, such as switches, is worse in geared-drive than in direct-drive wind turbines. We show that survival analysis is a useful tool for guiding the reduction of operating and maintenance costs of wind turbines.
ARTICLE | doi:10.20944/preprints201810.0300.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: allograft, xenograft, inflammation, sclerotic bone, implant failure, antigenic ossification
Online: 15 October 2018 (10:39:43 CEST)
Cadaver bone is possibly the most common transplant material used today. Common types of cadaver bone transplants are freeze dried bone allografts and xenografts. In the case of freeze dried bone allograft transplants, it was theorized that these materials mineralize by way of osteoinduction and stimulating osteogenesis. However, these theories have been proven false. It has been proposed that these materials mineralize via osteoconduction however, there are no studies to support this hypothesis. This study was undertaken to determine how these transplants mineralize and what type of bone they produce. Materials and Methods: This study is a histological analysis of human cadaver bone graft healing from the incipient stages of mineralization through completed mineralization. All cadaver bone grafts used for evaluation in this study were particulate bone graft materials in the maxilla or mandible. No block grafts were evaluated. Results: The mineralization of cadaver bone transplants was produced by an inflammatory response to the transplanted tissue. The histologic findings of the mineralized bone produced by this process was sclerotic bone. No resorption of cadaver bone graft particles was found. When loaded the sclerotic bone was found to fail through an accumulation of microfractures.Conclusions: Particulate freeze-dried bone allografts and xenografts do not heal via the normal processes of mineralization. Cadaver bone grafts produce significant inflammation and are hypothesized to mineralize by a process termed antigenic ossification. The process of antigenic ossification produces sclerotic bone that is not capable of self-repair which can ultimately lead to bone failure.
ARTICLE | doi:10.20944/preprints201805.0256.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: Implantation failure; Bisphenol A; 4-tert-octylphenol; calcium channel
Online: 18 May 2018 (07:38:04 CEST)
Miscarriage due to blastocyst implantation failure occurs in up to two-thirds of all miscarriage cases in human. The calcium ion has been shown to be involved in many cellular signal transduction pathways as well as in the regulation of cell adhesion, which is necessary for the embryo implantation process. Exposure to endocrine-disrupting chemicals (EDs) during early gestation results in disruption of intrauterine implantation and uterine reception, leading to implantation failure. In this study, ovarian estrogen (E2), bisphenol A (BPA), or 4-tert-octylphenol (OP), with or without ICI 182,780 (ICI) were injected subcutaneously from gestation day 1 to gestation day 3 post-coitus. The expression levels of the calcium transport genes were assessed in maternal uteri and implantation sites. The number of implantation sites was significantly low in the OP group, and implantation sites were absent in the E2 and EDs+ICI groups. There were different calcium transient transport channel expression levels in uterus and implantation site samples. The levels of TRPV5 and TRPV6 gene expression were significantly increased by EDs with/without ICI treatment in uterus. Whereas, TRPV5 and TRPV6 gene expression were significantly lower in implantation sites samples. NCX1 and PMCA1 mRNA levels were significantly decreased by OP and BPA in the implantation site samples. Compared to vehicle treatment in uterus, both the MUC1 mRNA and protein levels were markedly high in all but the BPA group. Taken together, these results suggest that both BPA and OP can impair embryo implantation through alteration of calcium transport gene expressions and by affecting uterine receptivity.
ARTICLE | doi:10.20944/preprints201803.0123.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: light-emitting diodes; failure mechanisms; current-stress aging; reliability
Online: 15 March 2018 (16:32:48 CET)
We have experimentally analyzed multi-azimuth degradation mechanisms that govern failures of commercially-available high-power (1 Watt) phosphor-coated white (hppc-W) light-emitting diodes (LEDs) covered with peanut-shaped lens under three current-stress aging (CSA) conditions. Comprehensive analyses focus on photometric, chromatic, electrical, thermal, and packaging characteristics. At the packaging level, (a) the decrease of the phosphor-conversion efficiency, (b) the yellow-browning of the optical lens, and (c) the darkening of the silver-coated reflective layer deposited with extraneous chemical elements (e.g., C, O, Si, Mg, and Cu, respectively) contribute collectively to the integral degradation of the optical power. By contrast, Ohmic contacts, thermal properties, and angles of maximum intensity remain unchanged after 3840 h aging in three cases. Particularly at the chip level, the formation of point defects increases the number of non-radiative recombination centers, and thus decreases the optical power during aging stages. Nevertheless, in view of the change of the ideality factor, the dopant activation and the annealing effect facilitate the increase of the optical power in two specific aging stages (192 h∼384 h and 768 h∼1536 h), respectively. This work offers a systematic guidance for the development of reliable LED-based light sources in general-lighting areas.
REVIEW | doi:10.20944/preprints202308.1514.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: multimodality imaging; advanced heart failure; extracorporeal cardiac support; cardiac transplant
Online: 22 August 2023 (07:49:59 CEST)
Advanced heart failure (AHF) presents a complex landscape with challenges spanning diagnosis, management, and patient outcomes. In response, the integration of multimodality imaging techniques has emerged as a pivotal approach. This comprehensive review delves into the profound significance of these imaging strategies within AHF scenarios. Multimodality imaging, encompassing echocardiography, cardiac magnetic resonance imaging (CMR), and cardiac computed tomography (CCT), stands as a cornerstone in the care of patients with both short- and long-term mechanical support devices. These techniques facilitate precise device selection, placement, and vigilant monitoring, ensuring patient safety and optimal device functionality. In the context of orthotopic cardiac transplant (OTC), the role of multimodality imaging remains indispensable. Echocardiography offers invaluable insights into allograft function and potential complications. Advanced methods, like speckle tracking echocardiography (STE), empower the detection of acute cell rejection. CMR and CCT further enhance diagnostic precision, especially concerning allograft rejection and cardiac allograft vasculopathy. This comprehensive imaging approach goes beyond diagnosis, shaping treatment strategies and risk assessment. By harmonizing diverse imaging modalities, clinicians gain a panoramic understanding of each patient's unique condition, facilitating well-informed decisions. Thus, this review underscores the irreplaceable role of multimodality imaging in elevating patient outcomes, refining treatment precision, and propelling advancements in the evolving landscape of advanced heart failure management.
REVIEW | doi:10.20944/preprints202308.1243.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: thyroid; heart; thyroid abnormalities; cardioprotection; heart failure; acute myocardial infarction
Online: 17 August 2023 (05:23:31 CEST)
The thyroid-heart relationship has a long and articulated history of its own, a history that en-compasses physiological and pathophysiological knowledge, the latter particularly in the context of cardiac diseases such as heart failure, arrhythmias and ischaemic heart disease. In recent years, molecular biology studies, in an experimental context, have highlighted the extraordinary dialogue that exists among the two systems in the field of cardioprotection, being an extremely important area for the treatment of cardiac diseases in both acute and chronic phases. In addi-tion, in the last few years, several studies have been carried out on the prognostic impact of al-terations in thyroid function, including subclinical ones, in heart disease, in particular in heart failure and acute myocardial infarction, with evidence of a negative prognostic impact of these and therefore with the suggestion to treat these alterations in order to prevent cardiac events, such as death. This review provides a comprehensive summary of the heart-thyroid relation-ship.
REVIEW | doi:10.20944/preprints202308.0074.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: HFNC; COPD; NIV; respiratory failure; respiratory support; critical care; LTOT
Online: 2 August 2023 (02:13:02 CEST)
High-flow Nasal Cannula (HFNC) oxygen therapy is gaining traction globally as a treatment for respiratory failure. There are several physiological benefits and there may be a growing patient preference for HFNC. In this narrative review, we aim to outline the basic mechanisms of HFNC, who can use it and review the literature regarding its utility both in the critical care setting, as well as in the home setting for chronic hypercapnic respiratory failure with an emphasis on Chronic Obstructive Pulmonary Disease (COPD). The role of non-pharmacological interventions like non-invasive ventilation (NIV) and HFNC in the prevention of hospital readmissions following acute exacerbations of COPD (AECOPD) is an area of increasing importance because randomised controlled trials and systematic reviews have found measures like nurse-led predischarge bundles to be clinically ineffective and to have a high cost per quality adjusted life year. This review therefore considers the evidence of NIV vs HFNC in the context of AECOPD and the application of HFNC at home in the prevention of AECOPD. We also look at applications of HFNC in specific settings, such as in the peri-operative period, emergency department, acute (mainly Critical Care) setting including in immunocompromised patients and palliative care.
ARTICLE | doi:10.20944/preprints202307.1156.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Acute Heart Failure; XGBoost; Explainable Artificial Intelligence; SHAP; Hematological parameters
Online: 18 July 2023 (04:47:24 CEST)
Background: Acute heart failure (AHF) is a serious medical problem that necessitates hospitalisation and often results in death. Patients hospitalised to the emergency department (ED) should therefore receive an immediate diagnosis and treatment. Unfortunately, there is not yet a fast and accurate laboratory test for identifying AHF. The purpose of this research is to apply the principles of explainable artificial intelligence (XAI) to the analysis of hematological predictors for AHF. Methods: In this retrospective analysis, 425 patients with AHF and 430 healthy individuals served as assessments. Patients' demographic and hematological information was analyzed to determine AHF. Important risk variables for AHF diagnosis were identified using LASSO feature selection. To test the efficacy of the suggested prediction model (XGBoost), a 10-fold cross-validation procedure was implemented. The area under the receiver operating characteristic curve (AUC), F1 score, Brier score, and Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were all computed to evaluate the model's efficacy. Permutation-based analysis and SHAP, were used to assess the importance and influence of the model's incorporated risk factors. Results: White blood cell (WBC), monocytes, neutrophils, neutrophil-lymphocyte ratio (NLR), red cell distribution width-standard deviation (RDW-SD), RDW-coefficient of variation (RDW-CV), and platelet distribution width (PDW) values were significantly higher than the healthy group (p<0.05). On the other hand, erythrocyte, hemoglobin, basophil, lymphocyte, mean platelet volume (MPV), platelet, hematocrit, mean erythrocyte hemoglobin (MCH) and procalcitonin (PCT) values were found to be significantly lower in AHF patients compared to healthy controls (p <0.05). When XGBoost was used in conjunction with LASSO to estimate AHF, the resulting model had an AUC of 87.9%, an F1 score of 87.4%, a Brier score of 0.036, and an F1 score of 87.4%. PDW, age, RDW-SD, and PLT were identified as the most crucial risk factors in differentiating AHF. Conclusions: The XGBoost model demonstrated exceptional performance in accurately estimating Acute Heart Failure, and the application of Explainable Artificial Intelligence effectively provided intuitive explanations for the model's estimations. The suggested interpretable model holds potential for the identification of patients at high risk, thereby facilitating the optimization of treatment and planning for follow-up in cases of AHF.
ARTICLE | doi:10.20944/preprints202307.0208.v1
Subject: Engineering, Control And Systems Engineering Keywords: multiplicative degradation model; time-to-failure model; hazard rate; majorization.
Online: 4 July 2023 (11:15:31 CEST)
In this paper, a novel strategy is adopted in a degradation model to affect the implied lifetime distribution. The multiplicative degradation model is utilized as a postulate in the model. It will be established that the implied lifetime distribution forms a classical mixture model. In this mixture model, time-to-failure is lying with some probabilities between two first passage times of the degradation process to reach two specified levels. Stochastic comparisons in the model under a change in the probabilities are studied. Several examples are provided to highlight the applicability of the results in the cases when typical degradation models are candidate.
REVIEW | doi:10.20944/preprints202306.2222.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Gut microbiota; Cardiovascular diseases; Trimethylamine N-Oxide; Heart failure; Atherosclerosis
Online: 30 June 2023 (11:58:11 CEST)
Much evidence reveals an important link between gut microbiota and the heart. In particular, the gut microbiota plays a key role in the onset of cardiovascular (CV) disease, including heart failure (HF). In HF, splanchnic hypoperfusion causes intestinal ischemia resulting in the translocation of bacteria and their metabolites into the blood circulation. Among these, the most important is the Trimethylamine N-Oxide (TMAO), which is responsible through various mechanisms for pathological processes in different organs and tissues. In this review, we summarise the complex interaction between gut microbiota and CV disease, particularly with HF, and the possible strategies to influence its composition and function. Finally, we highlight the potential role of TMAO as a novel prognostic marker and new therapeutic target of HF.
ARTICLE | doi:10.20944/preprints202306.0362.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: reactive oxygen species; angiotensin II; hypertrophy; psilocybin mushrooms; heart failure
Online: 6 June 2023 (03:07:37 CEST)
Psilocybin-containing mushrooms, commonly known as magic mushrooms have antidepressant effect, however, their safety in cardiovascular diseases such as heart failure is not fully known and needs to be investigated. Cardiac hypertrophy is an independent risk factor for heart failure morbidity and mortality. Angiotensin II (Ang-II) plays a major role in the pathogenesis of cardiac hypertrophy. We investigated the cardiovascular safety of extracts of Panaeolus cyanescens, Psilocybe natalensis, Psilocybe cubensis, and Psilocybe cubensis leucistic A+ strain mushrooms, well-known psilocybin-containing mushrooms in the Panaeolus and Psilocybe genus on Ang II-induced hypertrophy oxidative stress. The four mushrooms were grown, dried and extracted with 70% ethanol, cold and hot water. Extracts were tested for cytotoxicity on H9C2 cardiomyoblast cells. The cardiomyocytes were induced with (10 µM) AngII and treated with the three extracts of the four mushrooms over 48 hours. Control cells were serum starved but neither AngII induced nor treated while AngII cells were serum starved and stimulated with AngII but not treated. Losartan, an inhibitor of AngII type 1 receptor was used as positive control. Effects of the extracts on actin-filament labelling and cell surface area, mitochondrial activity, reactive oxygen species (ROS) and atrial natriuretic peptide levels were determined. Stimulation with AngII lowered cell viability, increased the cell width measurements and intracellular ROS levels significantly compared to control cells. The results indicated that the ethanol and water extracts of the four psilocybin mushrooms did not exacerbate the angiotensin II-induced hypertrophy conditions, but the extracts had cardio-protective activity against angiotensin II-induced oxidative stress. The phytochemical analysis of the extracts confirmed detections of known compounds with antioxidant and anti-inflammatory effects in the water and ethanol extracts of these four psilocybin mushrooms.
ARTICLE | doi:10.20944/preprints202305.0784.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Arrhythmogenic Cardiomyopathy; PKP2; Founder pathogenic variant; Arrhythmic events; Heart Failure
Online: 11 May 2023 (04:38:37 CEST)
Introduction and objectives: arrhythmogenic cardiomyopathy (ACM) is a hereditary heart disease defined by the progressive replacement of the ventricular myocardium with fibroadipose tissue, which can act as a substrate for arrhythmias, sudden death, or even give rise to heart failure (HF). Sudden death is frequently the first manifestation of the disease, particularly among young patients. The aim of this study is to describe a new pathogenic variant in the PKP2 gene. Methods: A descriptive observational study that included 8 initially non-interrelated families with a diagnosis of ACM undergoing follow-up at our HF and Familial Cardiomyopathies Unit, who were carriers of the NM_004572.3:c.775_776insG; p. (Glu259Glyfs*77) variant in PKP2 gene. The genetic testing employed next-generation sequencing for the index cases, and the Sanger method for the targeted study with family members. We compiled personal and family histories, demographic and clinical characteristics, data from the additional tests at the time of diagnosis, and arrhythmic events at diagnosis and during follow-up. Results: We included 47 subjects, of whom 8 were index cases (17%). Among the evaluated family members, 16 (34%) were carriers of the genetic variant, 3 of whom also had a diagnosis of ACM. The majority were women (26 patients; 55.3%), with a mean age on diagnosis of 48.9 ± 18.6 years, and a median follow-up of 39 [24-59] months. Worthy of note are the high incidence of arrhythmic events as the form of presentation and in follow-up (21.5% and 20.9% respectively), and the onset of HF in 25% of the sample. The most frequent ventricular involvements were right (4 patients 16.7%) and biventricular (4 patients 16.7%); we found no statistical differences in any of the variables analysed. Conclusions: This variant is a pathogenic variant of gene PKP2 that has not previously been described and is not present in the control groups associated with ACM. It has incomplete penetrance, a highly variable phenotypic expressivity, and was identified in 8 families of our geographical area in Malaga (Andalusia, Spain), where we can establish a founder effect and describe the clinical and risk characteristics.
ARTICLE | doi:10.20944/preprints202304.0866.v1
Subject: Engineering, Aerospace Engineering Keywords: Scarf patch; Film adhesive; Secondary bonding; Impact loading; Failure analysis
Online: 25 April 2023 (02:49:42 CEST)
This experimental study investigates the effect of scarf geometry in restoring the impact response of scarf patched 3 mm thick glass-fibre reinforced polymer (GFRP) matrix composite laminates. Traditional circular along with rounded rectangular scarf patch configurations considered as repair patches. Experimental measurements revealed that the temporal variations of force and energy response of the pristine specimen are close to that of circular repaired specimens. The predominant failure modes were witnessed only in repair patch which include the matrix cracking, fibre fracture, delamination and no discontinuity in adhesive interface was witnessed. When compared with the pristine samples, the top ply damage size of the of the circular repaired specimens is larger by 9.91 %, while that of the rounded rectangular repaired specimens is larger by 434.23 %. The results show that circular scarf repair is more suitable choice of repair approach under the condition of 37J low-velocity impact event even though the global force-time response is similar.
REVIEW | doi:10.20944/preprints202303.0228.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: heart failure; ejection fraction; left ventricle; systolic dysfunction; diastolic dysfunction
Online: 13 March 2023 (10:15:43 CET)
Heart failure (HF) diagnosis, phenotyping, prognosis, and treatment decisions are all based on the left ventricular ejection fraction (EF). Heart failure with mid-range EF (HFmrEF) is a third EF category for heart failure with an EF between 40 and 49 percent. Comparatively, heart failure with preserved EF or reduced EF has been largely unexplored. 10–25% of patients with HF have HFmrEF. Although HFmrEF has an intermediate clinical profile, it is more similar to HF with reduced EF, particularly because these patients have a high incidence of ischaemic heart disease. Heart failure with preserved EF has a lower risk of cardiovascular events than heart failure with reduced EF, which is milder. HFmrEF and HF with preserved EF patients have a similar or higher risk of non-cardiovascular adverse events than patients with HF with reduced EF. There is still a great deal of mystery surrounding HFmrEF. The purpose of this review is to describe the major pathophysiology of HFmrEF and its similarities and differences with the other two types of EF. It is the purpose of this paper to present a comprehensive overview of the currently available evidence in support of the pathophysiology of patients with HFmrEF. Further investigation of the pathophysiology, treatment, and prognosis of this condition will be needed in the future in order to better understand it.
ARTICLE | doi:10.20944/preprints202303.0119.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Antioxidant molecules; Cardiac health; Mechanism of heart failure; Cardiac activity
Online: 7 March 2023 (02:19:50 CET)
Although renal denervation (RDN) protects against hypertension, hypertrophy, and heart failure (HF), it is not clear whether RDN preserves ejection fraction (EF) during heart failure (HFpEF). To test this hypothesis, we simulated chronic congestive cardiopulmonary heart failure (CHF) by creating aorta-vena cava fistula (AVF) in C57BL/6J wild type (WT) mice. There are four ways to create experimental CHF: (1) myocardial infarction (MI) which is basically ligating coronary by instrumenting and injuring the heart; (2) trans-aortic constriction (TAC), although it mimics systematic hypertension but TAC again constricts aorta on top of the heart and exposes the heart; (3) acquired CHF such as by dietary factors, diabetes/salt diets etc. but it is multifactorial, and finally (4) AVF, which is the only one wherein AVF is created ~1cm below the kidney where the aorta and vena cava share the common middle-wall. By creating fistula, the red blood enters vena cava without an injury to the heart. This model mimics CHF such as during aging where with age the preload keeps increasing than the aging heart can pump out due to the weakened cardiac myocytes. This also involves the right ventricle to lung to left ventricle flow, thus creating congestion. The heart in AVF goes to transition from preserved to reduced EF (i.e., HFpEF to HFrEF). In fact, there are more models of volume overload, such as the pacing-induced and mitral valve regurgitation but these are also injurious models. Our lab is one of the original labs in creating and studying the AVF phenotype. The RDN was created by treating the cleaned bilateral renal artery. After 6 weeks, blood, heart, and renal samples were analyzed for exosome, cardiac regeneration markers and renal cortex proteinases. Cardiac function was analyzed by echocardiogram (ECHO). Fibrosis was analyzed with trichrome staining. The results suggested that there was robust increase in exosomes’ level in AVF blood, suggesting compensatory systemic response during AVF-CHF. During AVF there was no change in cardiac eNOS, Wnt1 and β-catenin, however; during RDN there was robust increase in eNOS, Wnt1 and β-catenin compared to the sham group. As expected in HFpEF there was perivascular fibrosis, hypertrophy and pEF. Interestingly, increased levels of eNOS suggested that despite fibrosis, the NO generation was higher that most likely contributed to pEF during HF. The RDN intervention revealed an increase in renal cortical caspase 8 and a decrease in caspase 9. Since caspase 8 is protective and caspase 9 is apoptotic, we suggest that RDN protects against renal stresses, and apoptosis. Our findings also suggest that RDN is cardioprotective during HFpEF via the preservation of eNOS and accompanied endocardial-endothelial function.
ARTICLE | doi:10.20944/preprints202211.0452.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Contrast bath. Edema, Elevation of feet 30 ° , Congestive heart failure
Online: 24 November 2022 (06:09:59 CET)
Background: Congestive heart failure is the inability to pump blood throughout the body which causes the walls to be unable to pump adequately. Purpose: This study aimed to ascertain the effect of a contrast bath with a 30 º elevation on the reduction of edema in congestive heart failure patients at Ulin General Hospital, Banjarmasin. Methods: The design of this study was quasi-experimental with an unequal control group design. The population is patients with congestive heart failure, and the sample used is successive sampling. 34 respondents were divided into two groups, 17 respondents in the intervention group and 17 in the control group. Results: The Mann-Whitney result value P = 0.027 (P < 0.05) represented a significant reduction in Bath contrast edema with 30º feet elevation in the intervention group and control group patients with congestive heart failure. Conclusion: Based on the results of this study, it is expected to be able to apply contrast showers with an elevation of 30 º in nursing services to reduce the degree of edema in congestive heart failure patients.
ARTICLE | doi:10.20944/preprints202208.0494.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: hydrocephalus; shunt failure; catheter occlusion; ventricular phantom; flow/pressure performance
Online: 29 August 2022 (12:45:35 CEST)
Objective: One of the major causes of cerebral ventricular shunt failure is proximal catheter occlusion. We describe a novel ventricular cerebrospinal fluid (CSF) flow replicating system that assesses pressure and flow responses to varied degrees of catheter occlusion. Methods: Ventricular catheter performance was assessed during conditions of partial and complete occlusion. The catheters were placed into a three-dimensionally printed phantom ventricular replicating system. Artificial CSF was pumped through the ventricular system at a constant rate of 1 ml/min to mimic CSF flow, with the proximal end of the catheter in the phantom ventricle. Pressure transducer and flow rate sensors were used to measure intra-phantom pressure, outflow pressure and CSF flow rates. The catheters were also inserted into silicone tubing and pressure was measured in the same manner for comparison with the phantom. Results: Pressure measured in the phantom ventricle did not change when the outflow of the ventricular catheter was partially occluded. However, the intraventricular phantom pressure significantly increased when the outflow catheter was 100% occluded. Flow through the catheter showed no significant difference in rate with any degree of partial occlusion of the catheter. At the distal end of the partially occluded catheters, there was less pressure compared with the nonoccluded catheters. This difference in pressure in partially occluded catheters correlated with the percentage of catheter hole occlusion. Conclusions: Our model mimics physiological dynamics of the CSF flow in partially and completely obstructed ventricular catheters. We found that partial occlusion of the catheter had no effect on CSF flow rate, but did reduce outflow pressure of the catheter.
ARTICLE | doi:10.20944/preprints202106.0081.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Heart failure; self-care behaviours; symptom recognition; nurse-led program.
Online: 2 June 2021 (14:23:22 CEST)
Patients with heart failure have difficulty in self-care management, as daily monitoring and recognizing symptoms do not readily triggers an action to avoid hospital admissions. The purpose of this study was to understand the impact of a nurse-led complex intervention on symptom recognition and fluid restriction. A latent growth model was designed to estimate self-care management and quality of life changes on patients with heart failure and assessed by a pilot study, for three months, to sixty-three patients (33 control, 30 intervention). Patients in the control group had a higher risk of hospitalisation (IRR 11.36; p<.001) and emergency admission (IRR 4.24; p<.001) at three-months follow-up. Analysis of the time scores demonstrated that the intervention group had a clear improvement in self-care behaviours (βSlope. Assignment_group=-.881; p<.001) and in the quality of life (βSlope. Assignment_group=1.739; p<.001). This study supports that a nurse-led program on symptom recognition and fluid restriction can have a positive impact on self-care behaviours and quality of life in patients with heart failure.
ARTICLE | doi:10.20944/preprints202102.0468.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Heart failure; self-care behaviours; symptom recognition; nurse-led program.
Online: 22 February 2021 (12:45:35 CET)
Patients with heart failure have difficulty in self-care management, as daily monitoring and recognizing symptoms do not readily trigger an action to avoid hospital admissions. The purpose of this study was to understand the impact of a nurse-led complex intervention on symptom recognition and fluid restriction. A latent growth model was designed to estimate self-care management and quality of life changes on patients with heart failure and assessed by a pilot study, for three months, to sixty-three patients (33 control, 30 intervention). Patients in the control group had a higher risk of hospitalisation (IRR 11.36; p<.001) and emergency admission (IRR 4.24; p<.001) at three-months follow-up. Analysis of the time scores demonstrated that the intervention group had a clear improvement in self-care behaviours (βSlope. Assign-ment_group=-.881; p<.001) and in the quality of life (βSlope. Assignment_group=1.739; p<.001). This study supports that a nurse-led program on symptom recognition and fluid restriction can have a positive impact on self-care behaviours and quality of life in patients with heart failure.
HYPOTHESIS | doi:10.20944/preprints202009.0346.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: Sepsis; SIRS; oxic sulphidic oscillator; risk prediction; multiorgan failure; chemocline
Online: 16 September 2020 (04:07:17 CEST)
Life evolved in an euxinic world with subsequent oxic 'invasion' leading to two parallel but interconnected biospheres, hydrogen sulphide (H2S) and hydrogen peroxide (H2O2) exemplify these worlds respectively. Their concentration gradients have informational value in meromictic lakes. Similarly, it is posited, there exists a whole body chemocline in humans in which the two molecules form an inversely coupled oxic/sulphidic oscillator (OSO). The OSO is hormetic and characterised by a range of amplitudes and frequencies in health. Deviations from its baseline profile heralds the onset of SIRS before the appearance of clinical signs. Loss of oscillator status and transition to a steady state causes widespread intercellular and inter-organ communication failure presaging multi-organ dysfunction. The salient clinico-pathophysiological features of SIRS of any aetiology are emergent phenomena related to the OSO profile. Extent of recovery of organ function will mirror the recovery of the OSO profile thereby providing a tool to predict outcomes in SIRS.
CASE REPORT | doi:10.20944/preprints202008.0640.v1
Subject: Medicine And Pharmacology, Pulmonary And Respiratory Medicine Keywords: VIP; COVID-19; respiratory failure; vasoactive intestinal peptide; aviptadil; ARDS
Online: 28 August 2020 (11:38:23 CEST)
Background: Vasoactive Intestinal Peptide (VIP) is known to bind to and protect the Alveolar Type II cell by blocking replication of the SARS-CoV-2 virus, upregulating surfactant production, blocking apoptosis, and blocking cytokine effects. RLF-100 (Aviptadil), a synthetic form of Vasoactive Intestinal Peptide (VIP) has been granted Fast Track Designation and is currently in phase 2/3 placebo-controlled trials. FDA has granted Emergency Use IND and Expanded Access Protocol approval for the use of RLF-100 in patients whose comorbidities render them ineligible for inclusion in the ongoing pivotal trial. Methods: This report describes the first 6 patients with Acute Respiratory Failure in Critical COVID-19, enrolled under Emergency Use IND were treated with three successive 12-hour infusions of intravenous Aviptadil at 50/100/150 pmol/kg/hr, while continuing to receive maximal ICU care. Results: Median patient follow-up time is 14 days. So far, all treated patients have survived. Improved radiographic appearance of typical “ground glass” COVID-19 features to varying degrees is seen in all patients within 72 hours. Improvement in blood oxygenation is seen in all patients, with complete remission from respiratory failure in 4 of 6 patients. An average 56% reduction in inflammatory markers was seen, together with a median 4 point reduction in the NIAID Ordinal Scale. 2/6 patients were discharged from the hospital and 1 patient was downgraded to the general medicine floor. Comment: The short term survival of 6/6 patients with respiratory failure in the setting of COVID-19 and major comorbidity is the most dramatic response ever seen with an antiviral agent. Improvement in radiographic appearance, oxygenation requirement, and inflammatory markers is consistent with in vitro evidence of direct anti-viral effect.