ARTICLE | doi:10.20944/preprints202205.0244.v1
Subject: Engineering, Automotive Engineering Keywords: failure mode and effect analysis (FMEA); model-based design; automatic generation tool; fault injection simulation
Online: 18 May 2022 (12:40:58 CEST)
In the development of the safety-critical systems, it is important to perform Failure Modes and Effects Analysis (FMEA) process to identify potential failures. However, traditional FMEA activities tend to be considered difficult and time-consuming tasks. To compensate for the difficulty of the FMEA task, various types of tools are used to increase the quality and the effectiveness of the FMEA reports. This paper explains an Automatic FMEA tool which integrates the Model-based Design (MBD), FMEA, and Simulated Fault Injection techniques in a single environment. The Automatic FMEA tool has the following advantages compared to the existing FMEA analysis tool. First, the Automatic FMEA tool automatically generates FMEA reports compared to the traditional spreadsheet-based FMEA tools. Second, the Automatic FMEA tool analyzes the causality between the failure modes and the failure effects by performing model-based fault injection simulation. In order to demonstrate the applicability of the Automatic FMEA, we used the electronic fuel injection system (EFI) Simulink model. The results of the Automatic FMEA were compared to that of the legacy FMEA.
ARTICLE | doi:10.20944/preprints202201.0002.v1
Subject: Mathematics & Computer Science, Numerical Analysis & Optimization Keywords: Failure Mode and Effect Analysis (FMEA); Pythagorean Fuzzy Dimensional Analysis (PFDA); Value Stream Mapping (VSM); Outsourcing Process (OP); Risk Analysis (RA).
Online: 4 January 2022 (12:23:06 CET)
Manufacturing corporations has the acceptance of the Outsourcing Process (OP) to improve industrial activities as well as to archive the revenue objectives, and with this, Risk Analysis (RA) tools are constantly used to assure expected results. Failure Mode and Effect Analysis (FMEA) is one of preferred RA tools, moreover, it is proven that FMEA adds uncertainty because of the human participation at the RA, afterward it is demonstrated that Pythagorean Fuzzy Dimensional Analysis – FMEA – Value Stream Mapping (PFDA-FMEA-VSM) method removes the uncertainty in RA, likewise it aids to the stakeholders for decision making, giving more advantages improving the use of the resources on the project. This document exhibits a real case scenario in a manufacturing firm applying PFDA-FMEA-VSM method adapted for manufacturing OP. The application of PFDA-FMEA-VSM shows solid RA results, removing the human intervention uncertainty added to the risk ranking, gives advantages to the stakeholders for visualize the main risks in detailed diagram, as well as make easier to take better decisions on where to apply resources and mitigate risks during OP.
ARTICLE | doi:10.20944/preprints202012.0429.v1
Subject: Engineering, Automotive Engineering Keywords: Product Design (PD); Failure Mode and Effect Analysis (FMEA); Dimensional Analysis (DA); Pythagorean Fuzzy Sets (PFS)
Online: 17 December 2020 (12:02:58 CET)
Product Design is getting nowadays new challenges on developing new products, since the industry is in a rush to introduce products into the marketplace, where customers demand products faster, cheaper, and free of failures. In the meantime, global companies are always trying to improve their Product Design process to get advantages over their competitors using proven tools like FEMA and mixing methodologies like Fuzzy theories with FMEA. Even today using all this tools and combination of methodologies there is a gap to address and it is required a robust risk analysis solving current issues in the electronic industry. This document aims to reveal a novel integrated method, where Failure Mode and Effect Analysis, Pythagorean Fuzzy Sets and Dimensional Analysis are cohesive into a model that minimize the uncertainty of the ranking and prioritization over the Failure Mode and Effect Analysis execution, helping to identify risks within an accurate grade over possible failures in the Product Design process. A real practical example is used to show the proposed method, where it is identified a robust methodology integration and solid and results using a sensitivity analysis.
ARTICLE | doi:10.20944/preprints202012.0312.v1
Subject: Engineering, Automotive Engineering Keywords: Bayesian Network; Root Cause Analysis; Failure Mode and Effect Analysis; Lithium-Ion 15 Battery Cell; Failure Propagation; Multi-Stage Production; Manufacturing Process; Process Optimization; Scrap Rate
Online: 14 December 2020 (09:31:30 CET)
The production of lithium-ion battery cells is characterized by a high degree of complexit due to numerous cause-effect relationships between process characteristics. Knowledge about the multi-stage production is spread among several experts, rendering tasks such as failure analysis challenging. In this paper, a method is presented, which includes expert knowledge acquisition in production ramp-up by combining Failure Mode and Effects Analysis (FMEA) with a Bayesian Network. We show the effectiveness of this holistic method by building up a large scale, cross-process Bayesian Failure Network in lithium-ion battery production. Using this model, we are able to conduct root cause analyses as well as analyses of failure propagation. The former support operators in identifying root causes once a cell possesses a specific failure by calculating most-probable explanations matched to the individual battery cell data. The latter enable us to analyze propagation of failures and deviations in the production chain and thus provide support for placement of quality gates, leading to a significant reduction in scrap rate. Moreover, it gives an insight into which process steps are key drivers for which final product characteristics.
ARTICLE | doi:10.20944/preprints201907.0127.v1
Subject: Mathematics & Computer Science, Analysis Keywords: comorbidities; congestive heart failure; health informatics; Bayes networks; clustering; risk assessment; clinical decision making
Online: 9 July 2019 (04:16:43 CEST)
Comorbidities can have a cumulative effect on hospital outcomes of care, such as the length of stay (LOS), and hospital mortality. This study examines patients hospitalized with Congestive Heart Failure (CHF), a life-threatening condition, which, when it coexists with a burdened disease profile, the risk for negative hospital outcomes increases. Since coexisting conditions co-interact, with a variable effect on outcomes, clinicians should be able to recognize these joint effects. In order to study CHF comorbidities, we used medical claims data from CMS. After extracting the most frequent cluster of CHF comorbidities, we: (i) Calculated, step-by-step, the conditional probabilities for each disease combination inside this cluster (ii) Estimated the cumulative effect of each comorbidity combination on the LOS and hospital mortality (iii) Constructed (a) Bayesian, scenario-based graphs and (b) Bayes-networks to visualize results. Results show that, for CHF patients, different comorbidity constructs have variable effect on the LOS and hospital mortality. Therefore, dynamic comorbidity risk assessment methods should be implemented for informed clinical decision making in any ongoing effort for quality of care improvements.
ARTICLE | doi:10.20944/preprints201901.0183.v1
Subject: Engineering, Electrical & 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/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.
REVIEW | doi:10.20944/preprints202102.0519.v1
Subject: Earth Sciences, Atmospheric Science 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/preprints201901.0220.v1
Subject: Life Sciences, Biochemistry 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/preprints202101.0113.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: Complexity Analysis & Mitigation; Software Architecture & Design, Safety; Quality; Fragility; Failure Obviation
Online: 6 January 2021 (11:45:48 CET)
Studies have found critical software malfunctions responsible for some of the worst accidents in recent times. These malfunctions are often only minor defects that snowball into large problems; a few lines of code is all it takes. Complexity, safety, quality, and resilience are among the key attributes defining a software’s operational success. There are many leading factors for complexity, such as increases in the product size, the rate of requirement changes, and the number and type of stakeholders, and failure to manage these issues efficiently always has the same consequence, i.e., massive failure and sometimes technological catastrophe. This work analyzes some of the architecture, design, and implementation guidelines used as detection and mitigation techniques. It also discusses the safety considerations, as considering how the steam industry has handled safety issues could offer some guidance for ensuring safety. Complexity in such systems also causes some of the worst side effects from the quality auditor's perspective. While failures in the software are hard to predict, one of the most significant ways of showing preparedness is practicing software resilience. New mitigation areas, such as the fragility spectrum and failure obviation, and their usage for building a safer system are analyzed. Also discussed are various architecture styles in practice and the dramatic effect human factors can have on the success of the software being developed.
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.
REVIEW | doi:10.20944/preprints201703.0177.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: sildenafil; phosphodiesterase-5 inhibitors; chronic heart failure; meta-analysis
Online: 22 March 2017 (18:12:47 CET)
Background: In patients with pulmonary arterial hypertension, substantial clinical benefits have been reported with the use of phosphodiesterase-5 inhibitors(PDE5i) . Moreover, some studies would have proven useful effects of PDE5i also on the clinical picture of the pulmonary hypertension(PH) secondary to left-sided chronic heart failure(CHF). Methods: We performed a meta-analysis comprising randomized controlled trials ( RCTs) which had compared PDE5i ( mostly sildenafil) with placebo in CHF patients. Results: 14 studies, including 928 patients overall , were admitted to the meta-analysis. In heart failure with reduced left ventricular ejection fraction(HFREF), PDE5i, compared to placebo, significantly improved the composite of death and hospitalization (OR= 0.28; 95% CI: 0.10 to 0.74). They also improved peak VO2 (difference in means[MD]: 3.76; 95% CI: 3.27 to 4.25), six-minutes walk distance ( (6MWD)( MD, 22.7 meters ; 95% CI, 8.19 to 37.21) and pulmonary arterial systolic pressure (MD: -11.52 mmHg; 95% CI: -15.56 to -7.49). Conversely, in CHF with preserved left ventricular ejection fraction ( HFpEF), PDE5i were shown not to yield any beneficial effect concerning the investigated endpoints. Conclusions: In HFREF, PDE5i were shown to improve the composite of death and hospitalization, as well as exercise capacity and pulmonary hemodynamics. Conversely, in HFpEF, no significant clinical, ergospirometric or hemodynamic betterment was achieved using PDE5i treatment.
ARTICLE | doi:10.20944/preprints201810.0438.v1
Subject: Engineering, Other 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/preprints202006.0204.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: Presepsin; Sepsis; Sequential Organ Failure Assessment (SOFA) score; alkaline phosphatase (ALP); Bile
Online: 16 June 2020 (09:43:45 CEST)
Presepsin is a diagnostic and prognostic biomarker of sepsis; however, elevated presepsin levels have also been documented without sepsis. This study aims to retrospectively analyze the laboratory parameters and Sequential Organ Failure Assessment (SOFA) score affecting presepsin levels in 567 patients. Some patients with elevated presepsin levels exhibited renal dysfunction or elevation of biliary enzymes despite a low SOFA score. The univariate regression analysis revealed a close correlation between presepsin levels and SOFA score, serum creatinine (CRE), blood urea nitrogen, and biliary enzymes. In addition, a multivariate regression analysis revealed that SOFA score, alkaline phosphatase (ALP), and CRE independently affected presepsin levels significantly. The analysis of covariance (ANCOVA) revealed that presepsin levels were significantly higher in patients with hepatobiliary disease. Besides, we found that patients who presented with the dilatation of intra- or extrahepatic bile ducts and the elevation of ALP or total bilirubin exhibited remarkable high presepsin levels in the bile. Furthermore, the presepsin production in the liver’s Kupffer cells was established by immunostaining in patients who received surgical liver resection. Overall, this study elucidates that biliary enzymes’ elevation affects presepsin levels, presepsin exists in high concentrations in the bile, and is positive in Kupffer cells.
REVIEW | doi:10.20944/preprints202105.0432.v1
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/preprints202104.0357.v1
Subject: Materials Science, Biomaterials Keywords: cavitation erosion; ion implanta; wear; failure analysis; cobalt alloy; stellite 6; damage mechanism; phase transformation
Online: 13 April 2021 (13:13:29 CEST)
From the wide range of engineering materials traditional Stellite 6 alloy exhibits excellent cavitation erosion (CE) resistance. In this work, the effect of nitrogen ion implantation of HIPed Stellite 6 on the improvement of CE resistance and both cobalt-rich matrix phase transformation due to nitrogen implantation and CE were stated. The CE resistance of stellites ion-implanted by 120 keV N+ ions two fluences: 5x1016 cm-2 and 1x1017 cm-2 were comparatively analysed with the unimplanted stellite and AISI 304 stainless steel. CE tests were conducted according to ASTM G32 with stationary specimen method. Erosion rate curves and mean depth of erosion confirm that the nitrogen implanted HIPed Stellite 6 two times exceeds the resistance to CE than unimplanted stellite, and has almost 10 times higher CE reference than stainless steel. The X-ray diffraction (XRD) confirms that HIPed Stellite 6 nitrogen ion implantation favours transformation of the ɛ(hcp) to γ(fcc) structure. Unimplanted stellite ɛ-rich matirx is less prone to plastic deformation than γ and consequently, increase of γ phase effectively holds carbides in cobalt matrix and prevents Cr7C3 debonding. This phenomenon elongates three times the CE incubation stage, slows erosion rate and mitigates the material loss. Metastable γ structure formed by ion implantation consumes the cavitation load for work-hardening and γ → ɛ martensitic transformation. In further CE stages, phases transform as for unimplanted alloy namely, the cavitation-inducted recovery process, removal of strain, dislocations resulting in increase of fcc phase. The CE mechanism was investigated using a surface profilometer, atomic force microscopy, SEM-EDS and XRD. HIPed Stellite 6 wear behaviour relies on the plastic deformation of cobalt matrix, starting at Cr7C3/matrix interfaces. Once the Cr7C3 losing their restrain, are debonding and removed. Carbides detachment creates cavitation pits which initiate cracks propagation through cobalt matrix, the loss of matrix phase and CE proceeds with a detachment of massive chunk of materials.
ARTICLE | doi:10.20944/preprints202112.0458.v1
Subject: Engineering, Marine Engineering Keywords: Dam breach parameters; dam failure scenario; flood hazard; flood hydrodynamics; flood simulation; simulated natural hazard
Online: 28 December 2021 (18:13:16 CET)
The risk related to embankment dam breaches needs to be evaluated in order to prepare emergency action plans. The physical and hydrodynamic parameters of the flood wave generated from dam-failure event correspond to various breach parameters such as width, slope and formation time. This study aimed to simulate dam-breach failure scenario of Yabous dam (NE Algeria) and analyze its influence on areas (urban and natural environments) downstream the dam. The simulation was completed using the sensitivity analysis method in order to assess the impact of breach parameters on the dam-break scenario. The propagation of flood wave associated to dam-break was simulated using the one-dimensional HEC-RAS hydraulic model. This study ap-plied a sensitivity analysis of three breach parameters (slope, width, and formation time) in five sites selected downstream the embankment dam. The simulation showed that the maximum flow of the flood wave recorded at the level of the breach was 8768 m3/s, which gradually attenuated along the river course to reach 1579.2m3/s at about 8.5km downstream the dam. This study estab-lished the map of flood-prone areas that illustrated zones threatened with the flooding wave trig-gered by the dam failure due to extreme rainfall events. The sensitivity analysis showed that flood wave flow, height and width revealed positive and similar changes for the increase in adjustments (±25% and ±50%) of breach width and slope in the 5 sites. However, flood wave parameters of breach formation time showed significant trends that changed in the opposite direction compared to breach slope and width.
ARTICLE | doi:10.20944/preprints201710.0142.v1
Subject: Mathematics & Computer Science, Probability And Statistics Keywords: competing risks; masked causes of failure; Markov Chain Monte Carlo; Bayesian analysis; partly interval censored
Online: 21 October 2017 (02:16:43 CEST)
Bayesian analysis for masked data under competing risk frameworks is studied for the purpose of assessing the impact of covariates on the hazard functions when the failure time is exactly observed for some subjects but only known to lie in an interval of time for the remaining subjects. Such data, known as partly interval-censored data, usually result from periodic inspection. Dirichlet and Gamma processes are assumed as priors for masking probabilities and baseline hazards. The Markov Chain Monte Carlo (MCMC) technique is employed for the implementation of the Bayesian approach. The effectiveness of the proposed model is tested through numerical studies, including simulated and real data sets.
ARTICLE | doi:10.20944/preprints201907.0045.v1
Subject: Earth Sciences, Geology Keywords: Lithology performance; shear failure; surface methane capture borehole; shear strength
Online: 2 July 2019 (11:52:10 CEST)
The shear failure of surface methane capture borehole (SMCB) is the main cause of shortening life cycle of SMCB but lack of lithological analysis. In order to improve the stability of SMCB and improve efficient drainage period, it is of great significance to investigate the lithology performances for shear failure of SMCB. Based on the direct shear tests and geological method, the results shows that the shear displacement increases as the grain size decreases. Mechanical jump occurs at the lithological boundaries, which is mainly determined by the composition of rock specimens. The cohesion is the mainly possible reason for the step change of shear strength. Lithology with high quartz and low clay may effectively improve shear strength and failure resistance. Boreholes drilled into the weaker siltstone and mudstone sections may potentially experience preferential damage due to the larger shear displacement and shear strength. Protective measures at these sections may improve the stability of the borehole casing. The probing data where it was found that boreholes closure validated the prediction.
REVIEW | doi:10.20944/preprints202008.0557.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: transplantation; dental implant; marginal bone loss; implant failure rate; systematic review; periodontitis; periodontal diseases; oral health
Online: 25 August 2020 (13:45:34 CEST)
This systematic review investigates the failure rate and marginal bone loss (MBL) of dental implants placed in Solid-organ transplant (SOT) patients compared to healthy controls. Three databases (PubMed, Web of Sciences and the Cochrane Library) were searched up to June 2020 (PROSPERO CRD42019124896). Case-control and cohort studies reporting data failure rate and marginal bone loss (MBL) of dental implants placed in SOT patients were included. The risk of bias of observational studies was assessed through the Newcastle-Ottawa Scale (NOS). Four case-control studies fulfilled the inclusion criteria, all of low risk of bias. Meta-analyses revealed consistently lower implant failure rate than control populations at patient and implant levels. SOT patients had a significant difference of -18% (p-value <0.001) of MLB towards healthy patients. SOT status poses no serious threat to implant survival. Overall, this group of patients presented lower levels of dental implant failure rate and marginal bone loss compared to otherwise healthy patients. Further intervention trials with wider sample size and longer follow-ups are necessary to confirm these summary results.
ARTICLE | doi:10.20944/preprints202105.0677.v1
Subject: Medicine & Pharmacology, Allergology Keywords: heart failure, phenotype, left ventricular ejection fraction, primary care, artificial intelligence, supervised analysis
Online: 27 May 2021 (14:08:53 CEST)
Artificial Intelligence are creating a paradigm shift in health care, being phenotyping patients through clustering techniques one of the areas of interest. Objective: To develop a predictive model to classify heart failure (HF) patients according to their left ventricular ejection fraction (LVEF), by using available data in Electronic Health Records (EHR). Subjects and methods: 2854 subjects more than 25 years old with diagnose of HF and LVEF measured by echocardiography were selected to develop an algorithm to predict patients with reduced EF using supervised analysis. Performance of the algorithm developed were tested in heart failure patients from Primary Care. To select the most influencing variables, LASSO algorithm setting was used and to tackle the issue of one class exceed the other one by a large proportion we used the Synthetic Minority Oversampling Technique (SMOTE). Finally, Random Forest (RF) and XGBoost models were constructed. Results: Full XGBoost model obtained the maximized accuracy, a high negative predictive value and the highest positive predictive value. Gender, age, unstable angina, atrial fibrillation and acute myocardial infarct are the variables that most influence FE value. Applied in the EHR data set with a total 25594 patients with an ICD-code of HF and no regular follow-up in Cardiology clinics, 6170 (21.1%) were identified as those pertaining to the reduced EF group. Conclusion: The algorithm obtained is able to rescue a number of HF patients with reduced ejection fraction that can be take benefit for a protocol with strong recommendation to succeed. Furthermore, the methodology can be used for studies with data extracted from the Electronic Health Records.
REVIEW | doi:10.20944/preprints202203.0301.v1
Subject: Medicine & Pharmacology, Pathology & 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/preprints202209.0378.v1
Subject: Mathematics & Computer Science, General 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/preprints201701.0080.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: wind turbine; failure detection; SCADA data; feature extraction; mutual information; copula
Online: 17 January 2017 (11:21:58 CET)
More and more works are using machine learning techniques while adopting supervisory control and data acquisition (SCADA) system for wind turbine anomaly or failure detection. While parameter selection is important for modelling a wind turbine’s health condition, only a few papers have been published focusing on this issue and in those papers interconnections among sub-components in a wind turbine are used to address this problem. However, merely the interconnections for decision making sometimes is too general to provide a parameter list considering the differences of each SCADA dataset. In this paper, a method is proposed to provide more detailed suggestions on parameter selection based on mutual information. Moreover, after proving that Copula, a multivariate probability distribution for which the marginal probability distribution of each variable is uniform is capable of simplifying the estimation of mutual information, an empirical copula based mutual information estimation method (ECMI) is introduced for an application. After that, a real SCADA dataset is adopted to test the method, and the results show the effectiveness of the ECMI in providing parameter selection suggestions when physical knowledge is not accurate enough.
BRIEF REPORT | doi:10.20944/preprints202004.0452.v1
Subject: Medicine & Pharmacology, General Medical Research 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.
REVIEW | doi:10.20944/preprints202001.0277.v2
Subject: Medicine & Pharmacology, General Medical Research 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.
ARTICLE | doi:10.20944/preprints202103.0393.v1
Subject: Engineering, Automotive Engineering Keywords: Carbon anode production; Crack generation; Discrete element method; Failure analysis; Second-order work criterion; Strain localization
Online: 15 March 2021 (13:53:17 CET)
An in-depth study of the failure of granular materials, which is known as a mechanism to generate defects, can reveal the facts about the origin of the imperfections such as cracks in the carbon anodes. The initiation and propagation of the cracks in the carbon anode, especially the horizontal cracks below the stub-holes, reduce the anode efficiency during the electrolysis process. In order to avoid the formation of cracks in the carbon anodes, the failure analysis of coke aggregates can be employed to determine the appropriate recipe and operating conditions. In this paper, it will be shown that a particular failure mode can be responsible for the crack generation in the carbon anodes. The second-order work criterion is employed to analyze the failure of the coke aggregate specimens and the relationships between the second-order work, the kinetic energy, and the instability of the granular material are investigated. In addition, the coke aggregates are modeled by exploiting the discrete element method (DEM) to reveal the micro-mechanical behavior of the dry coke aggregates during the compaction process. The optimal number of particles required for the failure analysis in the DEM simulations is determined. The effects of the confining pressure and the strain rate as two important compaction process parameters on the failure are studied. The results reveal that increasing the confining pressure enhances the probability of the diffusing mode of the failure in the specimen. On the other hand, the increase of strain rate augments the chance of the strain localization mode of the failure in the specimen.
ARTICLE | doi:10.20944/preprints202205.0313.v1
Subject: Engineering, Electrical & 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/preprints202009.0143.v1
Subject: Materials Science, General Materials Science 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.
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/preprints201903.0082.v1
Subject: Medicine & 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.
ARTICLE | doi:10.20944/preprints202207.0198.v1
Subject: Life Sciences, Other 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 & Pharmacology, Cardiology 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.
ARTICLE | doi:10.20944/preprints201608.0087.v1
Subject: Medicine & Pharmacology, Cardiology 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/preprints202109.0110.v1
Subject: Engineering, Biomedical & Chemical Engineering 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/preprints202010.0625.v1
Subject: Medicine & Pharmacology, Allergology 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 & Pharmacology, Cardiology 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
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.
ARTICLE | doi:10.20944/preprints202112.0350.v1
Subject: Medicine & Pharmacology, Pathology & 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.
Subject: Biology, 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/preprints202110.0208.v1
Subject: 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.
ARTICLE | doi:10.20944/preprints202010.0355.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: Probability Distribution Function; Weibull Distribution; Parameter Estimation; Mean Time Between Failures; Failure Rate; Mean Time To Repair; Downtime and Reliability
Online: 16 October 2020 (14:52:26 CEST)
Reliability analysis techniques are customary standard tools that are used for evaluating the performance of different equipment and devices in order to minimize their downtime. To predict the reliability, life data from a sample that is satisfactorily representative of the equipment should be fitted to the suitable statistical distribution. The parameterized distribution may be used to estimate essential characteristics such as failure rate; and probability at a precise time, as well as system reliability. In the current study, Weibull++/ALTA software package is used as a novel tool to fit the available data set to estimate the best fitted probability density function (PDF) using Maximum Likelihood (MLE) for parameter estimation. The determined distributions are then assessed using goodness-of-fit test to define how well it fits the available data set. There are multiple methods for determining goodness-of-fit. Weibull distributions and their special cases’ parameters have an effect on life times.
ARTICLE | doi:10.20944/preprints202005.0483.v1
Subject: Medicine & Pharmacology, Cardiology 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/preprints202103.0655.v1
Subject: Life Sciences, Biochemistry 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/preprints201810.0300.v1
Subject: Medicine & Pharmacology, Dentistry 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/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: 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/preprints201909.0238.v1
Subject: Engineering, Control & 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.
REVIEW | doi:10.20944/preprints201902.0030.v1
Subject: Medicine & Pharmacology, Cardiology 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/preprints201805.0256.v1
Subject: Life Sciences, Endocrinology & Metabolomics 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.
REVIEW | doi:10.20944/preprints202011.0011.v1
Subject: Medicine & Pharmacology, Allergology Keywords: liver failure 1; encephalopathy 2; delirium 3; coma 4; cirrhosis 5
Online: 2 November 2020 (10:00:51 CET)
Hepatic encephalopathy (HE) is a form of brain dysfunction that is specifically caused by liver insufficiency and/or portal-systemic shunt. The exact nature of HE is debated, so that conflicting uses of the term HE may cause inconsistencies in its detection and, in turn, issues with its management. This review highlights the meaning of the term HE on the basis of both its historical origins and current consensus. It also provides criteria for the diagnosis of the condition, on the basis of its phenotypes and the risk factors for its occurrence. The procedure for differential diagnosis from other conditions which result in similar phenotypes is considered, together with precipitants and confounders. Finally, the current multidimensional approach for the correct clinical recording of HE episodes is discussed.
ARTICLE | doi:10.20944/preprints202011.0185.v1
Subject: Medicine & Pharmacology, Allergology 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 & Pharmacology, Allergology 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/preprints202006.0045.v1
Subject: Medicine & Pharmacology, Other 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 & Pharmacology, Dentistry 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/preprints201705.0155.v1
Subject: Materials Science, Polymers & 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.
ARTICLE | doi:10.20944/preprints201810.0249.v2
Subject: Materials Science, Metallurgy Keywords: resistance projection welding; nugget size; maximum failure load; welding parameter
Online: 22 October 2018 (11:32:18 CEST)
The aim of this paper is to at first evaluate the influence of three key parameters including weld current, weld time and electrode force on nugget diameter and tensile strength in resistance projection welding. Then, a 2-D axis-symmetric finite element model is developed to simulate the projection welding and predict the nugget diameter. Finally, the FEM results are compared to experimental data to verify the simulation model and simulated results. In the finite element model, the temperature-dependent material properties were taken into account.
REVIEW | doi:10.20944/preprints202007.0568.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: SARS-CoV-2; COVID-19; respiratory failure; ARDS; ventilation; MODS; ECMO
Online: 24 July 2020 (04:00:50 CEST)
The Coronavirus Disease 2019 (COVID-19) pandemic has resulted in a significant surge of critically ill patients and an unprecedented demand on intensive care services. The rapidly evolving understanding of pathogenesis, limited disease specific evidence and demand-resource imbalances have posed significant challenges for intensive care clinicians. COVID-19 is a complex multisystem inflammatory vasculopathy with a significant mortality implication for those admitted to intensive care. Institutional strategic preparation and meticulous intensive care support are essential to maximising outcomes during the pandemic. The significant mortality variation observed between institutions and internationally, despite a single aetiology and uniform presentation, highlights the potential influence of management strategies on outcome. Given that optimal organ support and adjunctive therapies for COVID-19 have not yet been well defined by trial-based outcomes, strategies are predicated on existing literature and experiential learning. This review outlines the relevant pathophysiology and management strategies for critically ill patients with COVID-19, and shares some of the collective learning accumulated in a high volume Severe Respiratory Failure centre in London.
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, 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.
ARTICLE | doi:10.20944/preprints202106.0477.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Infective endocarditis; Kidney Transplantation; Survival analysis; graft failure; transplant infectious diseases
Online: 18 June 2021 (11:17:15 CEST)
Purpose: Kidney Transplant Recipients (KTRs) tend to develop infections with characteristic epidemiology, presentation and outcome. While infective endocarditis (IE) is among such complications in KTRs, literature is scarce. We describe the presentation, epidemiology, and factors associated with IE in KTRs. Methods: We performed a retrospective case/control study which included patients from two centers. First episodes of definite or possible IE (Duke criteria), in adult KTRs from January 2007 to December 2018 were included, as well as two controls per case, and followed until December 31 2019. Clinical, biological, and microbiological data and the outcome were collected. Survival was studied using the Kaplan-Meier method. Finally, we searched for factors associated with the onset of IE in KTRs by the comparison of cases and controls. Results: Seventeen cases and 34 controls were included. IE was diagnosed after a mean delay of 78 months after KT, mostly on native valves of the left heart only. Pathogens of digestive origin were most frequently involved (six Enterococcus spp, three Streptococcus gallolyticus and one Escherichia coli), followed by Staphylococci (three cases of S. aureus and S. epidermidis each). Among the risk factors evaluated only age was significantly associated with the occurrence of IE in our study (63.8 years for cases vs. 55.6 years for controls, P=0.03) Patient and death-censored graft survival were greatly diminished five years after IE compared to controls being 50.3% vs. 80.6% (p<0.003) and 29.7% vs. 87.5% (p<0.002), respectively. Conclusion: IE in KTRs is a disease that carries significant risks both for the survival of the patient and the transplant.
ARTICLE | doi:10.20944/preprints202202.0144.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: COVID-19 pandemic; Acute myocardial infarction; Congestive heart failure; Cardiovascular hospitalizations
Online: 10 February 2022 (02:47:49 CET)
Background A decline in cardiovascular hospitalizations was observed during the initial phases of the COVID-19 pandemic. We examine the continued effect of the pandemic on cardiovascular hospitalizations and the associated mortality rates during the first year of the pandemic in Israel. Methods We conduct a retrospective cohort study using the data of Clalit Health Services, the largest healthcare organization in Israel. We divide the Corona year into six periods (three lockdowns and three post-lockdowns) and compare the incidence rates of cardiovascular hospitalizations and their 30-day mortality during each period to the previous three years. Results The number of non-STEMI hospitalizations during the first year of the pandemic was 13.7% lower than the average of the previous three years (95% CI 11%-17%); STEMI hospitalizations were 15.7% lower (95% CI 13%-19%); and CHF hospitalizations were 23.9% lower (95%, CI 21%-27%). No significant differences in 30-day mortality rates were observed for AMI patients during most of the periods, whereas the annual 30-day all-cause mortality rate of CHF was 23% higher. Conclusions Hospitalizations for AMI and CHF were significantly lower during the first year of the pandemic relative to 2017–9. Mortality rates were higher in the case of CHF patients but not in the case of AMI patients, possibly due a change in the clinical acuity of patients arriving at the hospitals. We conclude that targeted public health messaging should be implemented, together with proactive monitoring in order to identify residual disability in patients that may have received non-optimal treatment during the pandemic.
ARTICLE | doi:10.20944/preprints202106.0276.v1
Subject: Medicine & Pharmacology, Allergology Keywords: left ventricular noncompaction; cardiomyopathy; heart failure; arrhythmia; conduction disturbances; molecular etiology; children
Online: 10 June 2021 (08:06:33 CEST)
Background: Left ventricular noncompaction (LVNC) is a genetically determined cardiomyopathy, that occurs following a disruption of endomyocardial morphogenesis. The purpose of this study was to identify the clinical characteristics and genetic profile of children with LVNC. Methods: From February 2008 to July 2020, a total of 32 children (median 11.5 years) with LVNC were prospectively enrolled and followed up for the median of 4.02 years. Diagnosis was made based on characteristic features of LVNC in echocardiography and cardiovascular magnetic resonance (CMR). Patients’ clinical symptoms, family history, ECG, Holter ECG and genetic tests were also evaluated. Results: The most common presenting symptom was heart failure (31% of children). ECG abnormalities were noted in 56% of patients. The most prominent features were ventricular arrhythmias, sinus bradycardia and paroxysmal third-degree atrioventricular block. Most of the patients (94%) met the criteria for LVNC and CMR confirmed this diagnosis in 82% of cases. The molecular etiology was found in 53% of children. Conclusion: Although heart failure and arrhythmias were very frequent in our study group, thromboembolic events and genetic syndromes were rare. For accurate and reliable assessment of children with LVNC, it is necessary to get to know their family history and detailed clinical profile.
ARTICLE | doi:10.20944/preprints201801.0041.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: biomarkers; heart failure with preserved ejection fraction (HFpEF); cBIN1; cBIN1 Score (CS)
Online: 7 January 2018 (13:49:49 CET)
Objective: We determined, in stable ambulatory heart failure with preserved ejection fraction (HFpEF) subjects and matched controls, the capability of a novel blood based cardiac-specific cBIN1 Score (CS) to diagnose heart failure and prognosticate future hospitalization. Background: Heart failure (HF) poses a costly health care burden worldwide with rising prevalence. Abnormal calcium signaling is intrinsic to HF pathophysiology and correlates with reduced expression of a cardiac membrane scaffolding protein, cardiac bridging integrator 1 (cBIN1). We hypothesize that CS, a numerical score derived from plasma cBIN1 concentration, is a diagnostic and prognostic biomarker of HF. Methods: Plasma cBIN1 is quantified by an ELISA test, and CS is calculated as the natural log of the normalized reciprocal of plasma cBIN1 concentration. We determined CS among 52 clinically stable individuals with HFpEF (LVEF ≥ 50%) (mean age 57 ± 15 years old, 63% men) and 104 age and sex matched volunteers with no known history of HF. We obtained plasma concentrations of NT-proBNP, a marker of volume status, as comparison. Baseline co-morbidities and one year longitudinal clinical information were obtained through electronic medical records. Results: Median CS is 0 (IQR -0.4 – 0.6) in the control cohort and is increased to 1.8 in the HFpEF cohort (IQR 1.5 – 2.3, p < 0.0001). For HFpEF diagnosis, CS has a receiver operating characteristic (ROC) area under the curve (AUC) of 0.94 (95% CI 0.95 – 0.99) and NT-proBNP of 0.89 (95% CI 0.83 – 0.95). Kaplan-Meier analysis of one year cardiovascular hospitalizations reveals that HFpEF patients with CS ≥ 1.8 have a hazard ratio (HR) of 4.0 (95% CI 1.4 – 11.2, p=0.009). Combining CS ≥ 1.8 with NT-proBNP ≥ 300 pg/mL, increases HR to 21.4 (95% CI 2.7 – 171.6, p=0.004). Conclusions: In a cohort of stable ambulatory HF patients with cardiomyopathies of multiple etiologies and preserved ejection fraction, a positive CS correlates with worsening myocardial health and predicts future hospitalization. CS, a marker of cardiac muscle health, provides a novel index to informing the management of stable ambulatory HF patients.
ARTICLE | doi:10.20944/preprints201801.0040.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: biomarker; heart failure with reduced ejection fraction (HFrEF); cBIN1; cBIN1 Score (CS)
Online: 7 January 2018 (12:51:36 CET)
Objective: We determined, in stable ambulatory heart failure with reduced ejection fraction (HFrEF) subjects and matched controls, the capability of a novel blood based cardiac-specific cBIN1 Score (CS), which assesses the health of cardiac muscle, to identify patients with known heart failure (HF) and to prognosticate future hospitalization. Background: Limited clinical tools are available in assessing cardiac muscle health in stable ambulatory patients. Cardiac bridging integrator 1 (cBIN1) is a cardiomyocyte t-tubule membrane scaffolding protein which regulates calcium signaling in cardiomyocytes, decreases in failing muscle, and is present in plasma in levels that correlate with cardiac content. We hypothesize that CS, a normalized index of plasma cBIN1 concentration, can function as a diagnostic and prognostic biomarker of HF. Methods: Plasma cBIN1 concentration is measured by an ELISA test, and CS is calculated as the natural log of the ratio of a constant population mean cBIN1 to measured cBIN1 concentration. We determined CS among 125 clinically stable individuals with HFrEF (LVEF ≤ 40%) (mean age 56 ± 10 years old, 79% men) and 125 age, sex matched volunteers with no known history of HF. We obtained plasma concentrations of NT-proBNP, a marker of volume status, as comparison. Baseline co-morbidities and 18-month longitudinal clinical information were obtained through electronic medical records. Results: CS follows a normal distribution with a median of 0 in the control population and median is significantly increased among HFrEF patients to 1.8 (IQR 1.4 – 2.1, p < 0.0001). CS diagnosed HFrEF with a receiver operating characteristic (ROC) area under the curve (AUC) of 0.93 (AUC is 0.98 for NT-proBNP, and combined CS and NT-proBNP AUC is 0.99). Unlike NT-proBNP, CS does not correlate with body mass index (BMI) in either the control or HFrEF population (Pearson’s r = -0.15, p = 0.12; Pearson’s r = 0.003, p = 0.97, respectively). NT-proBNP significantly correlates with renal function (Pearson’s r = -0.37, p = 0.001), while CS also has no correlation (Pearson’s r = 0.03, p = 0.71). During an 18-month follow-up, a high CS ≥ 1.8 at the initial visit predicted future cardiovascular hospitalizations (38% vs. 21%, p = 0.04, hazard ratio 2.0). NT-proBNP did not predict future cardiovascular hospitalizations. Conclusions: Plasma cBIN1 based CS is insensitive to BMI and renal function and differentiates myocardial health between patients with HFrEF versus matched controls. An abnormally high CS reflected poor intrinsic myocardial health and can predict future 18-month cardiac hospitalization in stable ambulatory patients.
REVIEW | doi:10.20944/preprints202102.0537.v1
Subject: Engineering, Automotive Engineering Keywords: void evolution; degradation; damage; fatigue; fatigue-life; failure prediction; , entropy; , thermodynamics; unified mechanics
Online: 24 February 2021 (09:59:27 CET)
This paper aims to provide an overall review of degradation, damage evolution and fatigue models in the literature of various engineering materials, mostly metals, and composites.
ARTICLE | doi:10.20944/preprints202111.0548.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics 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.
REVIEW | doi:10.20944/preprints202011.0357.v1
Subject: Medicine & Pharmacology, Allergology 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 & Pharmacology, Cardiology 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/preprints201803.0123.v1
Subject: Engineering, Electrical & 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.
ARTICLE | doi:10.20944/preprints202205.0282.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: cyclone; defect; hurricane; likelihood of failure; storm damage; typhoon; urban ecology; urban forestry
Online: 21 May 2022 (11:03:18 CEST)
Urban trees are often more sun- and wind-exposed than their forest-grown counterparts. These environmental differences can impact how many species grow – impacting trunk taper, crown spread, branch architecture, and other aspects of tree form. Given these differences, windthrow models derived from traditional forest production data sources may not be appropriate for urban forest management. Additionally, visual abnormalities historically labeled as “defects” in timber production may not have a significant impact on tree failure potential. In this study, we look at urban tree failures associated with Hurricane Irma in Tampa, Florida, USA. We used spatial analysis to determine if patterns of failure existed among our inventoried trees. We also looked at risk assessment data to determine which visual defects were the most common and the most likely to be associated with branch or whole-tree failure. Results indicate that there was no spatial pattern associated with the observed tree failures – trees failed or withstood the storm as individuals. While some defects like decay and dead wood were associated with increased tree failure, other defects like weak branch unions and poor branch architecture were less problematic.
REVIEW | doi:10.20944/preprints202009.0051.v1
Subject: Life Sciences, Biochemistry Keywords: PDE2; cAMP/cGMP crosstalk; natriuretic peptides; NO signalling; heart failure; arrhythmia; inflammation; cardiovascular disease
Online: 3 September 2020 (04:20:07 CEST)
Phosphodiesterases (PDEs) are the principal superfamily of enzymes responsible for degrading the secondary messengers 3’,5’-cyclic nucleotides cAMP and cGMP. Their refined subcellular localization and substrate specificity contribute to finely regulate cAMP/cGMP gradients in various cellular microdomains. Redistribution of multiple signal compartmentalization components is often perceived under pathological conditions. Thereby PDEs have long been pursued as therapeutic targets in diverse disease conditions including neurological, metabolic, cancer and autoimmune disorders in addition to numerous cardiovascular diseases. PDE2 is a unique member of the broad family of PDEs. In addition to its capability to hydrolyze both cAMP and cGMP, PDE2 is the sole isoform that may be allosterically activated by cGMP increasing its cAMP hydrolyzing activity. Within the cardiovascular system, PDE2 serves as an integral regulator for the crosstalk between cAMP/cGMP pathways and thereby may couple chronically adverse augmented cAMP signalling with cardioprotective cGMP signalling. This review provides a comprehensive overview of PDE2 regulatory functions in multiple cellular components within the cardiovascular system and also within various subcellular microdomains. Implications for PDE2 mediated crosstalk mechanisms in diverse cardiovascular pathologies are discussed highlighting the prospective use of PDE2 as a potential therapeutic target in cardiovascular disorders.
ARTICLE | doi:10.20944/preprints201810.0353.v1
Subject: Materials Science, Metallurgy Keywords: TRIP steel sheet; cross-die test; forming limit diagram; finite element analysis; failure mechanisms
Online: 16 October 2018 (11:12:42 CEST)
The formability and failure behavior of TRIP steel blanks were investigated through various stress states. The forming limit diagram (FLD) at fracture is constructed both experimentally and numerically. Numerical studies are performed to evaluate the applicability of different damage criteria in predicting the FLD as well as complex cross-die deep drawing process. The fracture surface and numerical results revealed that the material failed in a different mode for different strain path. Therefore, Tresca model which is based on shear stress accurately predicted the conditions where shear had the profound effect on the damage initiation, whereas Situ localized necking criterion was able to calculate the conditions which localization was dominant.
ARTICLE | doi:10.20944/preprints202208.0494.v1
Subject: Medicine & Pharmacology, Pediatrics 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 & Pharmacology, Allergology 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 & Pharmacology, Allergology 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 & Pharmacology, General Medical Research 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 & Pharmacology, Other 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.
BRIEF REPORT | doi:10.20944/preprints202007.0569.v1
Subject: Medicine & Pharmacology, Allergology Keywords: SARS-CoV-2; COVID-19; respiratory failure; ARDS; ventilation; ECMO
Online: 24 July 2020 (04:44:14 CEST)
The rapidly evolving understanding of Coronavirus Disease 2019 (COVID-19) respiratory failure pathogenesis, limited disease-specific evidence and demand-resource imbalances have posed significant challenges for intensive care clinicians. In this single-centre retrospective cohort study we describe the outcomes of COVID-19 patients admitted to Guy’s and St. Thomas’ NHS Foundation Trust (GSTT) critical care service. Patients were managed according to a local respiratory failure management pathway that was predicated on timely invasive ventilation when indicated and tailored ventilatory strategies according to pulmonary mechanics. Between 2nd March and 25th May 2020 GSTT critical care service admitted 316 patients with confirmed COVID-19. Of the 201 patients admitted directly through the Emergency Department with a completed critical care outcome, 71.1% survived to critical care discharge. These favourable outcomes may serve to inform the wider debate on the optimal ventilatory management in COVID-19.
ARTICLE | doi:10.20944/preprints202003.0229.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: heart failure; left ventricular assist device; cardiac recovery; mechanical circulation
Online: 13 March 2020 (10:11:43 CET)
In this paper, we aim to assess the electric current parameters and report the analysis of the associated degree of ventricular recovery during left ventricular assist device (LVAD) support. An assumption was made there is a linear relationship between ventricular recovery degree and the pump electric current pulsatility index (PI). The experimental study was carried out using the ViVitro Pulse Duplicator System with Sputnik 1 LVAD connected. Cardiac output (CO) and cardiac power output (CPO) were used as a measure of ventricular recovery degree. Different heart rates (HR) (59, 73, 86 bpm) and pump speeds (7600–8400 rpm in 200 rpm steps) were investigated. Ventricular stroke volumes in the range of 30–80 ml for each heart rate at certain pump speed were used. The obtained relationships of CO and CPO vs. PI was linear as the coefficients of determination for each regression curve were more than 0.8. CO vs. PI: R2=0.9218; 0.9271; 0.9172 and CPO vs. PI: R2=0.8517; 0.841; 0.8244 for HR=59 bpm; 73 bpm; 86 bpm, respectively. Study findings suggest that adequate interpretation of parameters could potentially serve as a valuable clinical tool to assess ventricular recovery based on LVAD infrastructure without requiring any special hemodynamic assessment.
ARTICLE | doi:10.20944/preprints201811.0440.v1
Subject: Biology, Animal Sciences & Zoology Keywords: kidney tissue; renal failure; human genetics; eastern part of India
Online: 19 November 2018 (10:01:55 CET)
Urolithiasis is a painful experience associated with hematuria, damage to kidney tissue and renal failure. It is a multi-factorial disorder while in India, its prevalence is rapidly increasing imposing a large burden for both healthcare and economy globally. In this article, we aimed to evaluate the association between genetic defects in SPP1 gene and urolithiasis from East Indian patients.75 urolithiasis patients were recruited from SSKM Hospital & Institute of Post Graduate Medical Education & Research (IPGME&R), Kolkata, India while 75 healthy controls were recruited from the same community. SNPs based areas of SPP1 gene were analyzed by direct sequencing to identify genetic defects.We identified 3 polymorphisms one synonymous and two 3’UTR variants rs1126616: p.Ala250Ala, rs1126772: 7315 a>g, rs9138: 7471 a>c in SPP1 gene in study individuals. Genotype and allele frequency analysis of these SNPs revealed that, rs9138 SNP was significantly associated with urolithiasis risk in East Indian patients. To our knowledge this is the first study reporting the role of the gene with urolithiasis in the population of West Bengal, India.
ARTICLE | doi:10.20944/preprints202107.0354.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: heart failure; mid-range ejection fraction; atrial fibrillation; cardiac inflammation; cardiac fibrosis; risk factors.
Online: 15 July 2021 (10:18:01 CEST)
Aims: Heart failure (HF) is frequently accompanied by atrial fibrillation (AF), a combination that worsens the outcomes of both diseases. Despite advances in the treatment of AF, it remains a serious and unsolved problem for clinicians and researchers. The aim of this study was to examine risk factors for incidents of paroxysmal and persistent AF in patients having heart failure with mid-range ejection fraction (HFmrEF). Methods. Overall, 71 patients with HFmrEF and non-valvular AF, including paroxysmal and persistent types, were enrolled in this study. As a control group, 42 HFmrEF patients without AF were also enrolled. All patients underwent detailed physical examination, including resting electrocardiography, echocardiography, and 24-hour ambulatory Holter monitoring. Levels of the inflammation markers high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) and the fibrotic marker transforming growth factor-β1 (TGF-β1) were measured by ELISA and expressed as odds ratios. Results: We show that paroxysmal AF was associated with higher diastolic blood pressure, whereas both paroxysmal and persistent forms of AF were associated with more frequent occurrence of hypertensive crisis episodes and greater body mass index. Progression from paroxysmal to persistent AF was associated with significant ventricular remodeling. Persistent and paroxysmal AF were associated with higher levels of inflammatory markers when compared to HFmrEF patients having no AF. In addition, TGF-1 was significantly increased in HFmrEF patients having persistent but not paroxysmal AF. Conclusions: Occurrence of AF, first paroxysmal and then persistent, in HFmrEF patients is associated with left ventricular remodeling and the appearance of systemic inflammatory and fibrotic markers. Changes in those parameters may be indicators by which to identify patients at increased risk of atrial fibrillation. Further studies are needed to determine the prognostic validity of these markers.
ARTICLE | doi:10.20944/preprints201804.0149.v1
Subject: Engineering, Energy & Fuel Technology Keywords: multi-layer hard roof; failure of overlying strata; ground pressure behaviour; longwall top coal caving
Online: 11 April 2018 (12:51:34 CEST)
In the extra-thick coal seams and multi-layered hard roofs, the longwall hydraulic support yielding, coal face spalling, strong deformations of goaf-side entry, and severe ground pressure dynamic events typically occur at the longwall top coal caving longwall faces. Based on the Key strata theory an overburden caving model is proposed here to predict the multilayered hard strata behaviour. The proposed model together with the measured stress changes in coal seam and underground observations in Tongxin coal mine provides a new idea to analyse stress changes in coal and help to minimise rock bursts in the multi-layered hard rock ground. Using the proposed primary Key and the sub-Key strata units the model predicts the formation and instability of the overlying strata that leads to abrupt dynamic changes to the surrounding rock stress. The data obtained from the vertical stress monitoring in the 38 m wide coal pillar located adjacent to the longwall face indicates that the Key strata layers have a significant influence on ground behaviour. Sudden dynamically driven unloading of strata was caused by the first caving of the sub-Key strata while reloading of the vertical stress occurred when the goaf overhang of the sub-Key strata failed. Based on this findings several measures were recommended to minimise the undesirable dynamic occurrences including pre-split of the hard Key strata by blasting and using the energy consumption yielding reinforcement to support the damage prone gate road areas. Use of the numerical modelling simulations was suggested to improve the key theory accuracy.
REVIEW | doi:10.20944/preprints202011.0563.v2
Subject: Medicine & Pharmacology, Allergology Keywords: Chromosomal instability; FA pathway; Radial figures; TGF pathway; MYC; p53; Bone marrow failure; cancer; physical abnormalities; infertility.
Online: 22 December 2020 (10:58:20 CET)
Abstract: Fanconi anemia (FA), a chromosomal instability syndrome, is caused by inherited pathogenic variants in any of 22 FANC genes, that cooperate in the FA/BRCA pathway. This pathway regulates the repair of DNA interstrand crosslinks (ICLs) through homologous recombination. In FA proper repair of ICLs is impaired, and accumulation of toxic DNA double strand breaks occurs. In order to repair this type of DNA damage, FA cells activate alternative error-prone DNA repair pathways, that may lead to the formation of gross structural chromosome aberrations of which radial figures are the hallmark of FA and their segregation during cell division are the origin of subsequent aberrations like translocations, dicentrics and acentric fragments. The deficiency in DNA repair has pleiotropic consequences in the phenotype of patients with FA, including developmental alterations, bone marrow failure and an extreme risk to develop cancer. The mechanisms leading to the physical abnormalities during embryonic development have not been clearly elucidated, however FA has features of premature aging with chronic inflammation mediated by pro-inflammatory cytokines, that results in tissue attrition, selection of malignant clones and cancer onset. Moreover, the effect of the FA/BRCA pathway in germinal cells, evidenced by infertility in patients with FA attests of chromosomal instability and cell death also occurring in the germinal compartment.
ARTICLE | doi:10.20944/preprints202102.0138.v1
Subject: Mathematics & Computer Science, Probability And Statistics Keywords: Mean time to failure; Poisson shock; Steady-state availability; Steady-state frequency; Supplementary variable technique.
Online: 4 February 2021 (13:07:59 CET)
This article examines the impact of some system parameters on an industrial system composed of two dissimilar parallel units with one repairman. The active unit may fail due to essential factors like aging or deteriorating, or exterior phenomena such as Poisson shocks that occur at various time periods. Whenever the value of a shock is larger than the specified threshold of the active unit, the active unit will fail. The article assumes that the repairman has the right to take any of two decisions at the beginning of the system operation: either a takes a vacation if the two units work in a normal way, or stay in the system to monitor the system until the first system failure. In case of having a failure in any of the two units during the absence of the repairman, the failing unit will have to wait until the repairman is called back to work. We suppose that the value of every shock is assumed to be i.i.d. with some known distribution. The length of the repairman’s vacation, repair time, and recall time are arbitrary distributions. Various reliability measures have been calculated by the supplementary variable technique and the Markov’s vector process theory. At last, numerical computation and graphical analysis have been given for a particular case to validate the derived indices.
ARTICLE | doi:10.20944/preprints202103.0382.v1
Subject: Medicine & Pharmacology, Allergology Keywords: diastolic dysfunction; heart failure; atrial fibrillation; atrial hypertension; left atrial pressure
Online: 15 March 2021 (13:02:14 CET)
Introduction: Left atrial hypertension is one of the pathophysiologies of heart failure with preserved ejection fraction. We hypothesized that left atrial pressure response (LAPR) to incremental pacing is higher in patients with atrial fibrillation (AF) and can predict left ventricular diastolic dysfunction. Methods: Patients requiring left atrial access as a part of a therapeutic procedure for AF (n=204, AF group) or supraventricular tachycardia (n=34, control group) were analyzed (male n=183, 54±12 years old). LAPR was measured during incremental pacing. Results: Baseline left atrial pressure and LAPR at all pacing rates were not different between the AF and control groups. They were higher in patients with a high E/e’ (≥ 8) than in those with a low E/e’ (< 8). LAPR at a pacing interval of 400ms and E/e' were positively correlated (r=0.373, p<0.001). Body mass index and a high E/e' were independent predictors of pacing-induced left atrial hypertension. Conclusions: The LAPR to incremental pacing was constant regardless of AF. The non-invasive echocardiographic marker E/e' reflected pacing-induced left atrial hypertension.
REVIEW | doi:10.20944/preprints202011.0216.v1
Subject: Engineering, Automotive Engineering Keywords: Failure Diagnosis; Aircraft Applications; Composite Materials; Non-Destructive Testing (NDT) Techniques
Online: 5 November 2020 (14:53:08 CET)
Diagnosis and prognosis of failures for aircrafts’ integrity are some of the most important regular functionalities in complex and safety-critical aircraft structures. Further, development of failure diagnostic tools such as Non-Destructive Testing (NDT) techniques, in particular, for aircraft composite materials, has been seen as a subject of intensive research over the last decades. The need for diagnostic and prognostic tools for composite materials in aircraft applications rises and draws increasing attention. Yet, there is still an ongoing need for developing new failure diagnostic tools to respond to the rapid industrial development and complex machine design. Such tools will ease the early detection and isolation of developing defects and the prediction of damages propagation; thus allowing for early implementation of preventive maintenance and serve as a countermeasure to the potential of catastrophic failure. In this paper, following a short introductory summary and definitions, this paper provides a brief literature review of recent research on failure diagnosis of composite materials with an emphasis on the use of NDT techniques in aerospace industry. In addition to this, within a some of significant NDT application extents, prognosis of composites is also briefly discussed.
ARTICLE | doi:10.20944/preprints202005.0288.v1
Subject: Mathematics & Computer Science, Probability And Statistics Keywords: COVID-19; Accelerated Failure Time; Proportional Hazard Model; Bayesian; Auto-Regression
Online: 17 May 2020 (08:50:22 CEST)
The constant news about the corona virus is scary. It is not possible to separate treatment for Cancer due to COVID-19. An effective treatment comparison strategy is needed. We need to have a handy tool to understand cancer progression in this unprecedented scenario. Linking different events of cancer progression is the need of the hour. It is a methodological challenge. We provide the solutions to overcome the issue with interval between two consecutive events in motivating head and neck cancer (HNC) data.
ARTICLE | doi:10.20944/preprints201906.0034.v1
Subject: Engineering, Control & Systems Engineering Keywords: ESP8266 WI-FI module; signal point of failure; IoT; heartbeat detection
Online: 5 June 2019 (09:49:32 CEST)
New developments in broadcast technology, such as the ad hoc wireless network and the detection devices that work, enable daily connections to the Internet, commonly referred to as the Internet of Things (IoT). IoT saw this as a support for the development of creative and contextual services and applications. The service can respond to the user's environment and preferences. Finite state machines are recently making waves when the issue of self-controlling systems come into the picture of designs. This research focuses on the design of a fault tolerant system that controls random failures impressed on the network. The method comprises of diodes, Resistors, Optocouplers, ESP8266 WI-FI Module Webpage with button, and two Arduinos which in effect will determine iteratively who to handle a failure at hand modelled as when the button on the webpage is pressed. In this work, a Heartbeat Detection and Monitoring System will be made using Arduino that detect the electrical state using the Pulse Sensor and show the readings in Beats Per Minute on the LED connected a microcontroller. It sends the texts to the server using the Wi-Fi module ESP8266 to signals can be monitored from the monitoring zone via the internet. This is reflected by the declaration of a master state by either of two Arduinos whenever the push button is pressed as observed on the codes. The result obtained from the research shows apparently, the state of the fault tolerance system none power deny of heartbeat condition connected to the LED.
ARTICLE | doi:10.20944/preprints201809.0437.v2
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: Fatigue; Delamination; Acoustic Emission; Failure Mechanisms; Composite Materials; Nanofibers, Marine Applications.
Online: 14 December 2018 (10:12:52 CET)
The use of high strength to weight ratio laminated composites is emerging in marine industry and applications as a very efficient solution for improving productivity. Nevertheless, delamination between the layers is a limiting factor for the wider application of laminated composites, as it reduces the stiffness and strengths of the structure. Interleaving nanofibrous mats between layers of composite laminates has been proved to be an effective method for improving composites delamination resistance. This paper aims to characterize the effect of interleaved nanofiber on mode I interlaminar properties and failure mechanisms when subjected to static and fatigue loadings. For this purpose, virgin and nanomodified woven laminates were subjected to Double Cantilever Beam (DCB) specimens. Static and fatigue tests were performed and the tests were monitored by acoustic emission technique. The mechanical results showed a 130% increase of delamination toughness for nanomodified specimens in the static loadings and more crack growth resistance in the fatigue loading. The AE results revealed that different type of failure mechanisms was the cause of these improvements for the modified specimens compared with the virgin ones.
ARTICLE | doi:10.20944/preprints202206.0214.v1
Subject: Life Sciences, Genetics Keywords: Adra1b; cardiac ischemia; hypoxia; Crem; gene expression control; gene expression coordination; gene hierarchy; heart failure; transcriptomic stoichiometry
Online: 15 June 2022 (07:37:53 CEST)
Decades of research identified numerous gene biomarkers of cardiac diseases whose restored sequence or/and expression level was hoped to recover the normal cardiac function. However, each human has unique and dynamic pathophysiological characteristics resulting from the unrepeatable combination of favoring factors such are: race, sex, age, medical history, diet, stress, exposure to toxins, habits etc. As such, no treatment fits everybody and finding personalized solutions is a top priority for medicine of 21st century. The Genomic Fabric Paradigm (GFP) provides the most theoretically possible comprehensive characterization of the transcriptome, its alterations in disease and recovery following a treatment. By attaching to each gene the independent average expression level, expression variation and expression coordination with each other gene, GFP delivers thousands times more information than the traditional analysis. This report presents the theoretical bases of the GFP and some applications to our microarray data from mouse models of post ischemic, and constant and intermittent hypoxia-induced heart failure. The GFP analyses revealed novel transcriptomic aspects of the gene expression control and networking under ischemic conditions. Through all-inclusive characterization of the transcriptome and the unrepeatable gene hierarchy in each condition, GFP is an essential avenue towards development of a truly personalized cardiogenomic therapy.
ARTICLE | doi:10.20944/preprints202109.0071.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: lysophospholipids; lysophosphatidic acids; cardiovascular diseases; HPLC-MS/MS; rodent models; pulmonary hypertension; chronic heart failure; hypertension
Online: 3 September 2021 (15:19:54 CEST)
Cardiovascular diseases (CVD) are the leading cause of premature death and disability in humans. Increasing data suggest that CVD is closely related to lipid metabolism and signaling. This study aimed to assess whether circulating lysophospholipids (LPL), lysophosphatidic acids (LPA) and monoacylglycerols (MAG) may be considered as biomarkers of CVD. For this objective, the evolution of the plasma levels of 22 compounds (13 LPL, 6 LPA and 3 MAG) was monitored by liquid chromatography coupled with tandem mass spectrometry (HPLC/MS²) in different rat models of CVD, i.e. angiotensin-II-induced hypertension (HTN), ischemic chronic heart failure (CHF) and sugen/hypoxia(SuHx)-induced pulmonary hypertension (PH). On one hand, there was modest changes on the monitored compounds in HTN (LPA 16:0, 18:1 and 20:4), LPC 16:1) and CHF (LPA 16:0, LPC 18:1 and LPE 16:0 and 18:0) models compared to control rats but these changes were no longer significant after correction for multiple testing. On the other hand, PH was associated with important changes in plasma LPA with a significant increase in the 16:0, 18:1, 18:2, 20:4 and 22:6 species. A deleterious impact of LPA was confirmed on isolated human pulmonary smooth muscle cells with an increase in their proliferation. This study demonstrates that circulating LPA species are increased in rats with PH and may contribute to the pathophysiology of this disease. Additional experiments are needed to assess whether the modulation of LPA signaling in PH may be of interest.
REVIEW | doi:10.20944/preprints201806.0444.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: vitamin C; ascorbic acid; cardiac surgery; antioxidant therapy; nutrient; oxidative stress; organ dysfunction; multi organ failure
Online: 27 June 2018 (12:29:23 CEST)
The pleiotropic biochemical and antioxidant functions of Vitamin C (Vit C) have recently sparked interest in its application in intensive care. Vit C protects important organ systems such as the cardiovascular, neurologic and renal system during inflammation and oxidative stress. Vit C also influences the systems of coagulation and inflammation and its application might prevent the development of organ damage. The current evidence of Vit C’s effect on the pathophysiological reactions during various acute stress events, such as sepsis, shock, trauma, burn and ischemia-reperfusion injury imposes the question, if the application of Vit C might be especially beneficial for cardiac surgery patients, who are routinely exposed to ischemia/reperfusion and subsequent inflammation, systematically affecting different organ systems. This review covers current knowledge about the role of Vit C in cardiac surgery patients with focus on its influence on organ dysfunctions. The relationships between Vit C and clinical health outcomes are reviewed with special emphasis on its application in cardiac surgery. Additionally, this review pragmatically discusses evidence regarding the administration of Vitamin C in every day clinical practice, tackling the issues of safety, monitoring, dosage and most the appropriate application strategy.
ARTICLE | doi:10.20944/preprints201911.0039.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: heart failure; Sacubitril/valsartan; Neprilysin inhibition; reduced ejection fraction; echocardiography; Nt-Pro-BNP; hemodynamic; remodeling
Online: 4 November 2019 (11:20:22 CET)
Background: Sacubitril/valsartan has been shown to be superior to enalapril in reducing the risks of death and hospitalization for heart failure (HF). However the effect on cardiac performance remains unknown. We sought to evaluate the effects of sacubitril/valsartan on clinical, bioumoral and echocardiographic parameters in patients with HFrEF. Methods: Sacubitril/valsartan was administered to 205 HFrEF patients. Results: Among 230 patients (mean age 59 ± 10 years, 46% with ischemic heart disease) 205 (89%) completed the study. After a follow–up of 10.49 (2.93±18.44) months, the percentage of patients in NYHA class III changed from 40% to 17% (p<0.001). Median N–Type natriuretic peptide (Nt-proBNP) decreased from 1865 ± 2318 to 1514 ± 2205 pg/mL, (p=0.01). Furosemide dose reduced from 131.3 ± 154.5 to 120 ± 142.5 (p=0.047). Ejection fraction (from 27± 5.9% to 30 ± 7.7% (p<0.001) and E/A ratio (from 1.67 ± 1.21 to 1.42 ± 1.12 (p=0.002)) improved. Moderate to severe mitral regurgitation (from 30.1% to 17.4%; p=0.002) and tricuspid velocity decreased from 2.8 ± 0.55 m/sec to 2.64 ± 0.59 m/sec (p<0.014). CONCLUSIONS: Sacubitril/valsartan induce “hemodynamic reverse remodeling” and in association with Nt-proBNP concentrations lowering improve NYHA class despite a diuretic dose reduction.
REVIEW | doi:10.20944/preprints202206.0100.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: CARDIOSIM©; numerical simulator; lumped parameter model; e-learning; mechanical circulatory support; ventilatory; cardiovascular system; heart failure; clinician
Online: 7 June 2022 (09:07:19 CEST)
This review is devoted to present the history of CARDIOSIM© software simulator platform, which was developed in Italy to simulate the human cardiovascular and respiratory system. The first version of CARDIOSIM© was developed at the Institute of Biomedical Technologies of the National Research Council in Rome. The first platform version published in 1991 ran on PC with disk operating system (MS-DOS) and was developed using the Turbo Basic language. The last version runs on PC with Microsoft Windows 10 operating system; it is implemented in Visual Basic and C++ languages. The platform has a modular structure consisting of seven different general sections, which can be assembled to reproduce different pathophysiological conditions. The software simulator can reproduce the most important circulatory phenomena in terms of pressure and volume relationships. It represents the whole circulation using a lumped-parameter model and enables the simulation of different cardiovascular conditions according to Starling’s law of the heart and a modified time-varying elastance model. Different mechanical ventilatory and circulatory devices have been implemented in the platform including thoracic artificial lung, ECMO, IABP, pulsatile and continuous right and left ventricular assist devices, biventricular pacemaker and biventricular assist devices. CARDIOSIM© is used in clinical and educational environment.
COMMUNICATION | doi:10.20944/preprints202206.0325.v3
Subject: Medicine & Pharmacology, Cardiology Keywords: autonomic failure; lean test; active stand; long covid; Post-COVID-19 condition
Online: 28 July 2022 (03:42:35 CEST)
Autonomic dysfunction is an increasingly recognised complication in chronic neurological conditions such as Parkinson’s disease , and other medical conditions, including diabetes mellitus, chronic fatigue syndrome, postural tachycardia syndrome with and without Ehlers-Danlos syndrome, fibromyalgia and recently Long Covid. Despite laboratory-based tests to evaluate normal and abnormal autonomic function, there are no home-based tests to record neuro-cardiovascular autonomic responses to common stimuli in daily life that are dependent on the normal functioning of the autonomic nervous system. We have developed an adapted blood pressure/heart Autonomic Profile (aAP) that can be used by an individual independently and repeatedly in a domiciliary setting to determine the physiological and symptomatic response to standing, food, and physical and mental (cognitive, emotional) activities. The aAP aids separating autonomic failure (often irreversible) from autonomic dysfunction. This helps the individual and attending healthcare professional understand the relationship between symptoms and common triggers in daily life and informs on self-management in debilitating conditions such as the postural tachycardia syndrome (PoTS) and Long Covid.
REVIEW | doi:10.20944/preprints202008.0257.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: COVID-19; SARS-CoV2; Acute Cardiac Injury; Arrhythmia; Heart Failure; Cardiogenic Shock
Online: 11 August 2020 (07:47:51 CEST)
A newly identified novel coronavirus named as severe acute respiratory syndrome-related coronavirus2 (SARS‐CoV 2) has given rise to the global pandemic. SARS-CoV2 which causes coronavirus disease 2019 (COVID-19), is a positive-stranded RNA virus with nucleocapsid. It binds to host angiotensin-converting enzyme2 (ACE2) receptor through surface glycoprotein (S protein). These ACE 2 receptors are attached to the cell membranes of many organs. Thus, COVID-19 does not only result in acute respiratory distress syndrome but also affects multiple organ systems, requiring a multidisciplinary approach to manage this disease. COVID-19 can damage the myocardial cells and result in fulminant myocarditis, acute cardiac injury, cardiomyopathy, heart failure, cardiogenic shock, or arrhythmia. COVID-19 seeds harmful immune response through cytokine storm leading to indirect organ damage. In this literature review, the available data is comprehended regarding cardiovascular complications in COVID-19, and the correlation of biomarkers with the disease activity is discussed. This literature review also highlights the important treatment options and outcomes of the individual study.
ARTICLE | doi:10.20944/preprints202001.0338.v1
Subject: Social Sciences, Business And Administrative Sciences Keywords: startup failure; competency approach; Critical Incident Technique; Information seeking; Customer service orientation
Online: 28 January 2020 (10:37:41 CET)
Purpose: There is limited research on the reasons behind startup failure, and none of the available studies use a competency approach. In this study we applied Spencer’s competency model to identify the competencies in startups which, according to their CEOs, contributed to failure. Methodology: Three coders analyzed the stories of 50 startup failures published online using modified Critical Incident Technique. Findings: Two salient competencies were identified playing a fundamental role in startup failures if missing: Information seeking and Customer service orientation. A network pattern of 9 more prevalent competency deficits was created: Technical/professional/managerial expertise, Analytical thinking, Flexibility, Self-control, Concern for order, quality and accuracy, Interpersonal understanding, Self-confidence, Team leadership and Teamwork and cooperation. Besides startup-specific behavior descriptions were added to Spencer’s competencies. Research implications: Competency approach and Critical Incident Technique method proved to be feasible to identify competency deficits in failed startups. Practical implications: The identified competency deficits offer relevant focus areas for the assessment and development of startup teams. Originality: The study provided research evidence to describe the competency deficits of startup teams that are connected to their failure.