REVIEW | doi:10.20944/preprints202004.0103.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: Coronavirus; SARS-CoV-2; Medical Laboratory; Resource-limited setting, Good Laboratory Practice (GLP)
Online: 7 April 2020 (12:11:35 CEST)
The 2019 Coronavirus pandemic which was initially referred to as 2019-nCoV, was first identified in Wuhan, China. Early response from the Chinese government included quarantine of infected persons, isolation and total lockdown of Wuhan province to prevent further spread. With the spread of the disease across national borders and declaration of the disease as a global pandemic, there has been a robust response by the international community to contain this deadly virus and prevent its further spread worldwide. Africa is not left out of this rampaging pandemic with documented cases in over 40 countries and still rising. Although extensive studies have been carried out on the novel SARS-CoV-2 on its pathogenesis, mode of infection and virulence but much is still unknown. However, potentially infectious samples are received routinely in the medical laboratory for analysis. This technical note reviews good laboratory practice (GLP) and processes across the different specialities of Medical Laboratory practice that should minimize the risk of infection to laboratory staff especially in resource-limited settings.
ARTICLE | doi:10.20944/preprints202109.0421.v1
Online: 24 September 2021 (09:04:57 CEST)
From gene expression studies to identifying microbes quantitative polymerase chain reaction (qPCR) is widely used in research and medical diagnostics. In transmittable diseases like the Ebola outbreak in West Africa (2014-2016), or the present SARS-CoV2 pandemic qPCR plays a key role in the detection of infected patients. Although the technique itself is decades old with reliable approaches (eg. TaqMan essay) in the diagnosis of pathogens many people showed distrust in it during the SARS-CoV2 outbreak. This came mainly from not understanding or misunderstanding the principles of qPCR. This situation motivated us to design a simple laboratory practical class, in which students have opportunities to understand the underlying principles of qPCR and its advantages in microbiological diagnosis. Moreover, during the exercise, students can develop skills such as handling experimental assays, and the ability to solve problems, discuss their observations. Finally, this activity brings them closer to the clinical practice and they can see the impact of the science on real life. The class is addressed to undergraduate students of biological sciences.
ARTICLE | doi:10.20944/preprints201808.0535.v1
Subject: Biology, Anatomy & Morphology Keywords: Chironomus riparius, laboratory cultures, experimental evolution
Online: 30 August 2018 (15:57:20 CEST)
Chironomus riparius is a well-established model organism in various fields such as ecotoxicology and ecology, and therefore environmental preferences, ecological interactions and metabolic traits are well-studied. With the recent publication of a high-quality draft genome, as well as different population genetic parameters such as mutation and recombination rate, the species can be used as an alternative to the Drosophila models in experimental population genomics or molecular ecology. To facilitate access to this promising experimental model species for a wider range of researchers, we describe experimental methods to first create and sustain long term cultures of C. riparius and then use them to perform repeatable and comparable experiments for various research questions.
SHORT NOTE | doi:10.20944/preprints202206.0048.v1
Subject: Biology, Anatomy & Morphology Keywords: craniofacial; laboratory animal; mental foramen; mental nerve; polecat
Online: 3 June 2022 (11:18:03 CEST)
In order to analyse asymmetries between hemimandibles, a sample of 24 mandibles from ferrets was studied by means of geometric morphometric methods, using a set of 3 landmarks and 14 semilandmarks, on the lateral aspect. Results showed that both size and shape played a significative role in mandibular asymmetry. For shape, there appeared significative fluctuating and directional asymmetries, with an especially high level for this latter. Landmarks corresponding to muscular attachments showed greater landmark asymmetry. This it is supported the hypothesis of a chewing side preference, e.g., a mastication-related driver for mandibular shape asymmetry.
ARTICLE | doi:10.20944/preprints201907.0296.v1
Subject: Life Sciences, Biotechnology Keywords: point-of-care; cholesterol; clinical diagnostics; laboratory test
Online: 26 July 2019 (01:13:11 CEST)
Managing blood cholesterol levels is important for the treatment and prevention of diabetes, cardiovascular disease, and obesity. An easy-to-use, portable cholesterol blood test will accelerate more frequent testing by patients and at-risk populations. We aim to evaluate the performance of smartphone-based point-of-care cholesterol blood tests as compared to that of hospital-grade laboratory tests. We used smartphone systems that are already familiar to many people. Because smartphone systems can be carried around everywhere, blood can be measured easily and frequently. We compared the results of cholesterol tests with those of existing clinical diagnostic laboratory methods. We found that smartphone-based point-of-care lipid blood tests are as accurate as hospital-grade laboratory tests (N=116, R>0.97, P<0.001 for all 3 cholesterol blood tests: total cholesterol, high density lipoprotein, and triglyceride). Our system will be useful for those who need to manage blood cholesterol levels to motivate them to track and control their behavior.
ARTICLE | doi:10.20944/preprints201902.0259.v1
Subject: Social Sciences, Econometrics & Statistics Keywords: Green pesticides; Agricultural subsidies; Product certification; Laboratory experiment
Online: 27 February 2019 (15:08:30 CET)
This paper studies the impact of agricultural subsidies and product certification on the use rate of green pesticides based on experimental economics. We found that agricultural subsidies effectively increased the utilization rate of green pesticides. If the agricultural subsidies raised from 20% to 100%, the green pesticides’ using rate increased by 438.51%. We also found that product certification increased the utilization rate of green pesticides by 376.16%%.The increase of agricultural subsidies is more effective than the product certification. Under a higher proportion of agricultural subsidies, farmers’ behavior will maintain “status bias”. Therefore, there are three suggestions proposed. Firstly, because of high price of green pesticides and lower production, the subsidies for agricultural materials should raise greatly to effectively improve the utilization rate of green pesticides. It is recommended that green pesticide provided free of charge in some wealthy areas. Secondly, both subsidies and product certification can improve the use rate of green pesticides. However, since the effect of agricultural subsidies is better than product certification, and farmers may have status bias. Therefore, it is recommended to give priority to the substantial increase on the proportion of agricultural subsidies, and then to product certification.
ARTICLE | doi:10.20944/preprints201807.0594.v2
Subject: Behavioral Sciences, Applied Psychology Keywords: cheating behavior, cheating during exam, 2nd medical laboratory
Online: 30 August 2018 (13:46:11 CEST)
Cheating during examination is now day serious problem spatially in Ethiopia where many students sit in one class to exam. When cheating occurs in medical schools, it has serious consequences for human life, social values, and the economy. Even though, cheating on exams has existed in any department, with unknown reason, prevalence of cheater among 2nd year laboratory students were high. So that assessing factors and improving cheating behavior of the students are mandatory to create competitive graduated students. To identify factors and to improve cheating behavior action research study design was conducted among 2nd year medical laboratory student. Criterion sampling technique was used to selects sixteen cheater students among 2nd year laboratory students. To gather necessary data, we used focus group discussions, individual interview, open-ended questionnaire and observation and collected information by using hand writing notes. During exam different cheating methods used by students like using a system of signals, writing on hands, desks and copy the other students answer. While the compelling reasons for cheating were like hard courses, hard exams, time pressure and fear of failure. To improve cheating behavior of the student’s different action strategies were taken like prepared exam by using code, arrangement sitting style during exam and sit with brainy students during class, reading and discussion. Most students were trying to done exam by themselves but their results are not good as previously. So that, we need more future action plan to avoid cheating behavior of the students. During, the next action plan we will be taken the remaining main action strategies and action evaluation we will be expected 50% of participants will be avoided their cheater behavior and done exam independently without forced by the environment.
ARTICLE | doi:10.20944/preprints202104.0723.v1
Subject: Social Sciences, Accounting Keywords: Biomedical Laboratory Science; Simulator; EEG; simulation pedagogy; content analyses
Online: 27 April 2021 (13:10:04 CEST)
Methods based on simulation pedagogy are widely used to practice hands on skills in safety environment. The usability of an EEG-simulator on clinical neurophysiology course was evaluated. Second year biomedical laboratory science students (N=35) on this course was included in the study. They were divided into three groups. Two groups used the EEG simulator with different feedback modes and one group without use of the simulator. Results was expected to reveal a correlation between user experience and learning outcomes. This study made used of a mixed method study design. During the study students were asked to keep a learning diary throughout the course on their experience. Diaries were analyzed qualitatively based on content analyses. Quantitative analyses based on an UX questionnaire that measures classical usability aspects (efficiency, perspicuity, dependability) and user experience aspects (novelty, stimulation) and the students’ feelings to use simulator. The quantitative data was analyzed using SPSSTM software. The quantitative and qualitative analyses showed that the use of EEG-simulator which was evaluating teaching-learning process have an extra benefit in clinical neurophysiology education and students felt that simulator is useful in learning. The simulation debriefing session should be followed by a full theoretical and practical session. Students compare their learning from the simulator with that of the actual placement which fosters the reflective practice of learning again deepening the understanding of the EEG electrode placement and different wave patterns.
ARTICLE | doi:10.20944/preprints202210.0126.v1
Subject: Biology, Other Keywords: Dengue; Touba; Mass gathering; Field Investigation; Mobile laboratory; Phylogeny; Phylogeography
Online: 10 October 2022 (11:21:49 CEST)
Dengue virus (DENV) was detected in Senegal in 1979 for the first time. Since 2017, unprecedented frequent occurrence of DENV outbreaks was noticed yearly. In this context, epidemiological and molecular evolution data are paramount to decipher virus diffusion route. In the current study, a dengue outbreak occurred in Senegal in 2018 in the context of the largest religious gathering with 263 confirmed DENV cases out of 832 collected samples, including 25 life-threatening cases and 2 deaths. It was characterized by a co-circulation of dengue serotypes 1 and 3. Phylogenetic analysis based on the E gene revealed that the main detected serotype in Touba city was DENV-3 and belonged to Genotype III. Bayesian phylogeographic analysis was performed and suggested one viral introduction around 2017.07 (95 % HPD = 2016.61 – 2017.57) followed by cryptic circulation before identification of the first case on 01 October 2018. DENV-3 strains are phylogenetically related, with strong phylogenetic links between strains retrieved from Burkina Faso and West African countries. These phylogenetic data substantiate epidemiological data of the DENV-3 origin and spread between African countries and subsequent diffusion after religious mass events. The study also highlighted the usefulness of the Mobile Laboratory during outbreak response allowing rapid diagnosis resulting in improved patient management.
REVIEW | doi:10.20944/preprints202106.0295.v1
Subject: Medicine & Pharmacology, Allergology Keywords: machine learning; deep learning; neural network; tricorder; laboratory medicine; extraanalytics
Online: 10 June 2021 (13:30:26 CEST)
Laboratory medicine has evolved from a mainly manual profession, providing few selected test results to a highly automated and standardized medical discipline, generating millions of test results per year. As next inevitable evolutional step, artificial intelligence (AI) algorithms will need to assist us in structuring and making sense of the masses of diagnostic data collected today. Such systems will be able to connect clinical and diagnostic data and to provide valuable suggestions in diagnosis, prognosis or therapeutic options. They will merge the often so separated worlds of the laboratory and the clinics. When used correctly, it will be a tool, capable of freeing the physicians time so that he/she can refocus on the patient. In this narrative review I therefore aim to provide an overview of what AI is, what applications currently are available in healthcare and in laboratory medicine in particular. I will discuss the challenges and pitfalls of applying AI algorithms and I will elaborate on the question if healthcare workers will be replaced by such systems in the near future.
REVIEW | doi:10.20944/preprints202009.0063.v1
Subject: Keywords: COVID-19; disease severity; laboratory findings; biochemistry findings; immunology; hematology
Online: 3 September 2020 (07:35:46 CEST)
Aim: Abnormal laboratory findings have been shown to be associated with severe COVID-19. However, all aspects of this association have not been reviewed systematically. Therefore, the aim of this meta-analysis was to explore crucial laboratory parameters in severe COVID-19 infection. Methods: We performed the literature review of scientific articles indexed in electronic databases. Scientific search engines were used to perform the electronic literature search. After the removal of duplicates and selection of articles of interest, 30 studies were eligible to include. If heterogeneity was high (I2>50%), a random-effects model was applied to combine the data. Otherwise, a fixed-effects model was used.Results: A total of 5586 individuals were assessed (1555 patients with severe COVID-19 infection and 3452 with non-severe infection). Platelets, lymphocytes and serum albumin were significantly lower in severe patients while other biochemical and immunological parameters including prothrombin time, ALT, AST, total bilirubin, LDH, procalcitonin, CRP, IL-6, and IgA were significantly higher in patients with severe infection. Neutrophil and monocyte counts as well as hemoglobin level, D-dimer, hypersensitive troponin I, IL-2R, IgG and IgM levels were different between two groups; however, the difference was not statistically significant (All P-values >0.05). Conclusions: Lymphopenia, elevated liver enzymes, and high levels of inflammatory biomarkers are associated with severe COVID-19 infection.
ARTICLE | doi:10.20944/preprints201811.0431.v2
Subject: Physical Sciences, Other Keywords: authentic learning; work integrated learning; curriculum development; laboratory classes; proxemics
Online: 27 November 2018 (05:20:40 CET)
The traditional hands-on nature in science laboratory classes creates a sense of immediacy and a presence of authenticity in such learning experiences. The handling of physical objects in a laboratory class, and the immediate responses provided by these experiments, are certainly real-live observations, yet may be far from instilling an authentic learning experience in students. This paper explores the presence of authenticity in hands-on laboratory classes in introductory science laboratories. With our own laboratory program as a backdrop we introduce four general types of hands-on laboratory experiences and assign degrees of authenticity according the processes and student engagement associated with them. We present a newly developed type of hands-on experiment which takes a somewhat different view of the concept of hands-on in a laboratory class. A proxemics-based study of teacher-student interactions in the hands-on laboratory classes presents us with some insights into the design of the different types of laboratory classes and the pedagogical presumptions we made. A step-by-step guide on how to embed industry engagement in the curriculum and the design of an authentic laboratory program is presented to highlight some minimum requirement for the sustainability of such program and pitfalls to avoid.
REVIEW | doi:10.20944/preprints202007.0465.v1
Subject: Medicine & Pharmacology, Other Keywords: laboratory-acquired brucellosis; prevention; biosafety; cultures; identification; biochemical tests; MALDI-TOF; FISH; laboratory-acquired brucellosis; prevention; biosafety; cultures; identification; biochemical tests; MALDI-TOF; FISH
Online: 20 July 2020 (09:38:57 CEST)
Brucellosis is one of the most common etiologies of laboratory-acquired infections worldwide, and handling of living brucellae should be performed in a Class II biological safety cabinet. The low infecting dose, multiple portals of entry to the body, the great variety of potentially contaminated specimens, and the unspecific clinical manifestations of human infections facilitate the unintentional transmission of brucellae to laboratory personnel. Work accidents such as spillage of culture media cause only a small minority of exposures, whereas >80% of events result from unfamiliarity with the phenotypic features of the genus, misidentification of isolates, and unsafe laboratory practices such as aerosolization of bacteria and working on an open bench without protective goggles or gloves. Although the bacteriological diagnosis of brucellae by traditional methods is simple, the Gram stain and the biochemical profile of the organism, as determined by commercial kits, can be misleading, resulting in inadvertent exposure and contagion. The use of novel identification technologies is not hazard-free. The MALDI-TOF technology requires an initial bacterial inactivation step, while the instruments’ reference database may misidentify Brucella as belonging to other Gram-negative species. The rapid identification by the FISH method mistakes brucellar isolates for members of the closely related Ochrobactrum genus.
ARTICLE | doi:10.20944/preprints202301.0397.v1
Subject: Life Sciences, Microbiology Keywords: coranavirus; covid-19; diagnostic; epidemic; medical laboratory professionals; sars-cov-2
Online: 23 January 2023 (06:12:12 CET)
The disease COVID-19 is brought on by the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) First appeared in China in December 2019 and quickly spread around the world after being declared a worldwide pandemic by the World Health Organization in March 2020. COVID-19, Medical Laboratory Professionals, SARS-COV-2, Diagnostic, Importance and difficulties for testing were the selected terms to search the databases of PubMed and Google Scholar for previously published material. Many diagnostic tests are applied in corona virus detection like Droplet Digital PCR (ddPCR), Multiplex PCR, Loop-mediated Isothermal Amplification (LAMP) and more. There is a lack of availability of molecular and serologic tests that have been clinically validated or authorized by national or international regulatory bodies. Clinical laboratory experts are tackling threats to our global defense and wellness, including infectious diseases. The opportunity to express gratitude to the unsung medical laboratory heroes and COVID0-19 pandemic allies is now greater than ever. Each year, Medical Laboratory Professionals Week should honors those who contribute key diagnostic data that help save lives. This review article explore overall summary on testing methods including Important and Difficult Tasks for Medical Laboratories which will provide good message for better public health matter.
ARTICLE | doi:10.20944/preprints202103.0103.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Next Generation Sequencing; Laboratory automation; Hereditary Cancer; Genetic Testing; Clinical Genomics.
Online: 2 March 2021 (16:00:24 CET)
(1) Background: the NGS based mutational study of hereditary cancer genes is crucial to design tailored prevention strategies in subjects with different hereditary cancer risk. The ease of amplicon-based NGS library construction protocols contrasts with the greater uniformity of enrichment provided by capture-based protocols and so with greater chances for detecting larger genomic rearrangements and copy-number variations. Capture-based protocols, however, are characterized by a higher level of complexity of sample handling, extremely susceptible to human bias. Robotics platforms may definitely help dealing with these limits, reducing hands-on time, limiting random errors and guaranteeing process standardization. (2) Methods: We implemented and validated the complete automation of the SOPHiA GENETICS’ CE-IVD Hereditary Cancer Solution™ (HCS) libraries preparation workflow on the Hamilton’s STARlet platform. (3) Results: We demonstrate that this automated workflow, used for more than 1000 samples achieved the same performances of manual setup in terms of coverages and reads uniformity, with extremely lower variability of reads mapping rate onto the regions of interest. (4) Conclusions: This automated solution offers same reliable and affordable NGS data, but with the essential advantages of a flexible, automated and integrated framework, minimizing possible human errors and depicting a laboratory’s walk-away scenario.
ARTICLE | doi:10.20944/preprints202002.0378.v3
Subject: Medicine & Pharmacology, Other Keywords: Coronavirus Disease 2019; SARS-CoV-2; clinical features; laboratory; outcomes; epidemic.
Online: 11 March 2020 (10:35:01 CET)
Introduction: An epidemic of Coronavirus Disease 2019 (COVID-19) begun in December 2019 in China, causing a Public Health Emergency of International Concern. Among raised questions, clinical, laboratory, and imaging features have been partially characterized in some observational studies. No systematic reviews have been published on this matter. Methods: We performed a systematic literature review with meta-analysis, using three databases to assess clinical, laboratory, imaging features, and outcomes of COVID-19 confirmed cases. Observational studies, and also case reports, were included and analyzed separately. We performed a random-effects model meta-analysis to calculate the pooled prevalence and 95% confidence interval (95%CI). Results: 660 articles were retrieved (1/1/2020-2/23/2020). After screening by abstract/title, 27 articles were selected for full-text assessment. Of them, 19 were finally included for qualitative and quantitative analyses. Additionally, 39 case report articles were included and analyzed separately. For 656 patients, fever (88.7%, 95%CI 84.5-92.9%), cough (57.6%, 40.8-74.4%) and dyspnea (45.6%, 10.9-80.4%) were the most prevalent manifestations. Among the patients, 20.3% (95%CI 10.0-30.6%) required intensive care unit (ICU), with 32.8% presenting acute respiratory distress syndrome (ARDS) (95%CI 13.7-51.8), 6.2% (95%CI 3.1-9.3) with shock and 13.9% (95%CI 6.2-21.5%) of hospitalized patients with fatal outcomes (case fatality rate, CFR).Conclusion: COVID-19 brings a huge burden to healthcare facilities, especially in patients with comorbidities. ICU was required for approximately 20% of polymorbid, COVID-19 infected patients and this group was associated with a CFR of over 13%. As this virus spreads globally, countries need to urgently prepare human resources, infrastructure, and facilities to treat severe COVID-19.
ARTICLE | doi:10.20944/preprints201907.0155.v1
Subject: Medicine & Pharmacology, Pediatrics Keywords: immune system; immunedeficiency; respiratory tract infections; children; impedance; serum; laboratory diagnostics
Online: 11 July 2019 (09:12:55 CEST)
Despite considerable progress in the diagnosis of various diseases, an ideal, simple tool for diagnosing patients with respiratory tract infections has not yet been invented. Many simple diagnostic tests are widely available to most doctors, provided they are aware of the prevalence of primary immunodeficiency. Other, more accurate studies are available only to immunologists. The aim of the study was to investigate the occurrence of dependence between selected physical parameters of serum such as: electrical conductivity, electrical permeability, dielectric loss factor, and selected parameters of the immune system. In addition, we have also included the ionogram (Na, K, Cl, Ca, Mg) and glucose concentration. As a result of research, the statistically significant, but very weak correlations between impedance magnitude |Z| and platelet counts (PLT), mean platelet volume (MPV) and chloride ions (Cl-) were found. The statistically significant differences according |Z| between children with and without deficiency in parameters of the immune system were noticed. Values of |Z| are higher in the case of children without deficiency in parameters of the immune system. The method of impedance measurements presented in our work is significantly easier then biosensors presented by other scientists. Taking into account our results, it can be stated that this method is promising for fast and easy detection of immunological disorders.
ARTICLE | doi:10.20944/preprints202012.0496.v1
Subject: Life Sciences, Biochemistry Keywords: Hungateiclostridium thermocellum; adaptive laboratory evolution; RNA-seq; cellulosomal genes; EMP pathway; monosaccharides
Online: 21 December 2020 (10:36:00 CET)
Hungateiclostridium thermocellum ATCC 27405 is a promising bacterium with a robust ability to degrade lignocellulosic biomass complexes, including crystalline cellulose components, through a multienzyme cellulosomal system. In contrast, it exhibits poor growth on simple monosaccharides such as fructose and glucose. This phenomenon raises many important questions concerning its glycolytic pathways and sugar transport systems. Until now, the detailed mechanisms of H. thermocellum adaptation to growth on monosaccharides have been poorly explored. In this study, adaptive laboratory evolution was applied to train the bacterium on monosaccharides, and genome resequencing was used to detect the genes that had mutated during adaptation. RNA-seq data of the 1st-generation culture growing on either fructose or glucose revealed that several glycolytic genes in the EMP pathway were expressed at lower levels in these cells than in cellobiose-grown cells. After 8 generations of culture on fructose and glucose, the evolved H. thermocellum strains grew faster and yielded greater biomass than the nonadapted strains. Genomic screening also revealed several mutation events in the genomes of the evolved strains, especially in genes responsible for sugar transport and central carbon metabolism. Consequently, these genes could be applied as targets for further metabolic engineering to improve this bacterium for bioindustrial usage.
ARTICLE | doi:10.20944/preprints201811.0031.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: active distribution network; laboratory testbed; renewable energy sources; DC link; centralised control
Online: 2 November 2018 (07:08:47 CET)
This paper assesses the behaviour of active distribution networks with high penetration of renewable energy sources when the control is performed in a centralised manner. The control assets are the on-load tap changers of transformers at the primary substation, the reactive power injections of the renewable energy sources and the active and reactive power exchanged between adjacent feeders when they are interconnected through a DC link. A scaled-down distribution network is used as testbed to emulate the behaviour of an active distribution system with massive penetration of renewable energy resources. The laboratory testbed involves hardware devices, real-time control, and communication infrastructure. Several key performance indices are adopted to assess the effects of the different control actions on the system operation. The experimental results demonstrate that the combination of control actions enables the optimal integration of a massive penetration of renewable energy.
TECHNICAL NOTE | doi:10.20944/preprints202202.0087.v1
Subject: Engineering, Marine Engineering Keywords: swimming fins testing; biomimetics; fatigue testing; thermoplastics; laboratory stand; accelerat-ed fatigue testing
Online: 7 February 2022 (13:01:05 CET)
TThe aim of the work is to present a newly developed stand and methodology of accelerated tests of fatigue strength of flexible propellers and fins. The paper presents the design and concepts of the measuring elements used in the research. Test methodology and water stressing were devel-oped. The mechanical properties of the following materials were presented: Arnitel EL-550 and QUEO 8230 with the addition of PP / EVA 50/50 (polypropylene / ethylene-vinyl acetate) - in the proportion of 70/30 (QUEO 8230 / additive). The constructed test stand and a new method of fa-tigue testing of biomimetic fins made it possible to determine the number of fin movement cy-cles under a given load, which may facilitate the determination of a warranty for a newly intro-duced product. The current consumption by the fin drive and video monitoring allowed for the selection of the range of the number of movement cycles and the determination of the moment of fatigue cracks until the fin structure loses its capacity. During the analysis, the test results showed that the fins made of Arnitel EL-550 did not show changes in the measured values of the current and the force generated by the fin. For a fin made of QUEO 8230, at 35,000 cycles, there is a decrease in the current and force consumed, which indicates the initiation of fatigue damage to the fin. The performed tests can be the basis for the development of standards for the fatigue strength of flexible propellers.
ARTICLE | doi:10.20944/preprints202112.0320.v1
Subject: Life Sciences, Virology Keywords: African swine fever virus; laboratory diagnosis; commercial real-time PCR; performance; sensitivity; specificity
Online: 21 December 2021 (09:24:26 CET)
African swine fever (ASF) is one of the major threats to pig production, and real-time PCR (qPCR) protocols are integral part of ASF laboratory diagnosis. With the pandemic spread of ASF, commercial kits have risen on the market. In Germany, the kits have to go through an approval process and thus, general validation can be assumed. However, they were never compared to each other. In this study, 12 commercial PCR kits were compared to an OIE recommended method. Samples representing different matrices, genome loads, and genotypes were included in a panel that was tested under diagnostic conditions. The comparison included user-friendliness, internal controls, and the time required. All qPCRs were able to detect ASFV genome in different matrices across all genotypes and disease courses. With one exception, there were no significant differences when comparing the overall mean. The overall specificity was 100 % [95 % CI 87.66 - 100], and the sensitivity was between 95 % and 100 % [95 % CI 91.11 - 100]. As can be expected, variability concerned samples with low genome load. Concluding, all tests were fit for purpose. The test system can therefore be chosen based on compatibility and prioritization of the internal control system.
ARTICLE | doi:10.20944/preprints202012.0221.v1
Subject: Keywords: PUI (primarily undergraduate institution); laboratory; start-up; negotiation; undergraduate; support; funding; equipment; mentorship; community
Online: 9 December 2020 (11:16:48 CET)
Scientists who are interested in building research programs at primarily-undergraduate institutions (PUIs) have unique considerations compared to colleagues at research-intensive (R1) institutions. Maintaining a research program at a PUI holds unique challenges that should be considered before prospective faculty go on the job market, as they negotiate a job offer, and after they begin a new position. In this article we describe some of the considerations that aspiring and newly hired faculty should keep in mind as they plan out how they will set up a laboratory as a new Principle Investigator (PI) at a PUI. Anyone hoping to start a research program at a PUI should understand both the timeframe of interviews, job offers, and negotiations and the challenges and rewards of working with undergraduate researchers. Once a job is offered, candidates should be aware of the range of negotiable terms that can be part of a start-up package. Space and equipment considerations are also important, and making the most of shared spaces, existing infrastructure, and deals can extend the purchasing power of start-up funds as a new PIs builds their lab. PUIs’ focus on undergraduate education and mentorship leads to important opportunities for collaboration, funding, and bringing research projects directly into undergraduate teaching laboratories. A major focus of any new laboratory leader must be on building a productive, equitable, and supportive laboratory community. Equitable onboarding, mentorship plans, and formalized expectations, can all help build a productive and sustainable laboratory research program. However, important considerations about safety, inclusion, student schedules, and a PI’s own professional commitments are also extremely important concerns when working with undergraduates in research. A successful research program at a PUI will bring students into meaningful scientific inquiry and requires insights and skills that are often not the focus of scientific training. This article aims to describe the scope of setting up a new laboratory as a way to alleviate some of the burden that new and prospective faculty often feel.
ARTICLE | doi:10.20944/preprints201806.0360.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: Star block-copolymers; hybrid mesoscale simulation technique; rotational frequency; laboratory frame; Eckart frame; geometrical approach
Online: 22 June 2018 (15:12:59 CEST)
Star block-copolymers (SBCs) are macromolecules formed by a number of diblock copolymers anchored to a common central core, being the internal monomers solvophilic and the end monomers solvophobic. Recent studies have demonstrated that SBCs constitute a self-assembling building blocks with specific softness, functionalization, shape, and flexibility. Depending on different physical and chemical parameters the SBCs can behave as flexible patchy particles. In this paper, we study the rotational dynamics of isolated SBCs using a hybrid mesoscale simulation technique. We compare three different approaches to analyse the dynamics: the laboratory frame, the non-inertial Eckart's frame, and a geometrical approximation relating the conformation of the SBC to the velocity profile of the solvent. We find that the geometrical approach is adequate when dealing with very soft systems while in the opposite extreme, the dynamics is best explained using the laboratory frame. On the other hand, the Eckart frame is found to be very general and to reproduced well both extreme cases. We also compare the rotational frequency and the kinetic energy with the definitions of the angular momentum and inertia tensor different from recent publications.
ARTICLE | doi:10.20944/preprints201801.0032.v2
Subject: Earth Sciences, Environmental Sciences Keywords: triggering of debris flows; overland flow; infiltration; laboratory experiments; modelling; rain intensity-duration threshold curves
Online: 13 June 2018 (08:37:32 CEST)
Many studies, which try to analyze conditions for debris flow development, ignore the type of initiation. Therefore this paper deals with the following questions: What type of hydro-mechanical triggering mechanisms for debris flows can we distinguish in upstream channels of debris flow prone gullies? Which are the main parameters controlling the type and temporal sequence of these triggering processes and what is their influence on the meteorological thresholds for debris flow initiation? A series of laboratory experiments were carried out in a flume, 8 m long and with a width of 0.3 m. to detect the conditions for different types of triggering mechanisms. The flume experiments show a sequence of hydrological processes triggering debris flows, namely erosion and transport by intensive overland flow and by infiltrating water causing failure of channel bed material. On the basis of these experiments an integrated hydro-mechanical model was developed, which describes Hortonian and Saturation overland flow, maximum sediment transport, through flow and failure of bed material. The model was calibrated and validated using process indicator values measured during the experiments in the flume. Virtual model simulations, carried out in a schematic hypothetical source area of a catchment show that slope angle and hydraulic conductivity of the bed material determine the type and sequence of these triggering processes. It was also clearly demonstrated that the type of hydrological triggering process and the influencing geometrical and hydro-mechanical parameters may have a great influence on rainfall intensity-duration threshold curves for the start of debris flows.
ARTICLE | doi:10.20944/preprints202212.0345.v1
Subject: Engineering, Other Keywords: Laboratory Automation; Radiochemistry; Synthera; FASTlab; TRACERlab; iPhase; Synthra; Synthesis Module; Radiation Safety; Vacuum; Diaphragm Pump; Laboport; Arduino; LabVIEW
Online: 20 December 2022 (02:21:39 CET)
Vacuum pump wear is the most prevalent failure mode of the IBA Synthera® automated radiochemistry system. Rebuilding or replacing the pump causes equipment downtime and increases the radiation exposure of the service personnel. We built a dedicated test device to assess new or rebuilt pumps prior to installation, thus reducing downtime and radiation exposure during repairs. The Testbed incorporates a microprocessor that actuates the pump, valves, pressure sensor, and communicates with the user through lights, buttons, and an alphanumeric screen. The Testbed increases productivity and safety in the radiochemistry laboratory.
ARTICLE | doi:10.20944/preprints202107.0420.v1
Subject: Keywords: CURE; undergraduate research; natural selection; experimental evolution; molecular biology; genetics; structure- 46 function relationships; introductory biology; laboratory exercise
Online: 19 July 2021 (15:47:18 CEST)
Course-based Undergraduate Research Experiences (CUREs) in high-enrollment, introductory classes are a 37 potentially transformative approach to retaining more students in STEM majors. We developed and piloted a CURE 38 in the introductory biology courses at the University of Washington. This CURE focuses on analyzing experimental 39 evolution of antibiotic resistance in Escherichia coli and generates data on two topics relevant to clinical practice: 40 compensatory mutations and cross-drug effects. By studying mutations in central cellular machinery that confer drug 41 resistance, students not only gain insight into fundamental cellular phenomena, but also recognize the molecular 42 basis of a medically important form of evolutionary change, connecting genetics, microbiology, and evolution.
CASE REPORT | doi:10.20944/preprints202107.0469.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Research Infrastructures (RIs); Engineering Geological conditions; Integrated geophysical methods; Daya Bay Neutrino Laboratory (DBNL); China Spallation Neutron Source (CSNS)
Online: 21 July 2021 (08:17:01 CEST)
Research Infrastructures (RIs) are essential to achieve excellence in innovative scientific research. However, because of limited land availability and specific geological requirements, evaluating the viability of a site for a new RI can be a challenging task. Stringent safety construction requirements include developing site-specific architectural and geoengineering solutions, minimizing construction disturbances, and reinforcing rock and soil in a timely fashion. For successful development of the RIs in China, such as the Daya Bay Neutrino Laboratory (DBNL), and the China Spallation Neutron Source (CSNS), an integrated approach of joint geophysical methods including the electrical resistivity tomography (ERT), controlled-source audio-frequency magneto telluric (CSAMT)), gravity and seismic refraction methods, and geological mapping and surveys were carried out. Geophysical parameters, such as electrical resistivity, density, and seismic velocity show inverse proportion to the degree of rock fracturing or weathering. The results show that the low values of geophysical parameters suggest the weathered/fractured rock, while high values reveal the fresh bedrock. The Engineering Geological Suitability Index (EGSI) value can represent the individual EGSI values at a constant and summed over varying depths. EGSI methodology is an improvement on the existing siting process, and has been applied this to CSNS. Our integrated approach provides clearer insight of the subsurface for site suitability of RIs in challenging engineering geological conditions, and removes any ambiguity caused by a single geophysical parameter. The obtained geological knowledge of the area not only provides engineers with much-needed information about the construction conditions of a potential site, but also gives scientists the opportunity to explore the local geology. In this study, we demonstrate our innovative approach for siting RIs, as demonstrated by the synthetic evaluation of the site location and utilization for two established RIs (DBNL and CSNS).
ARTICLE | doi:10.20944/preprints202004.0472.v1
Subject: Chemistry, Analytical Chemistry Keywords: 3-D printing; additive manufacturing; distributed manufacturing; laboratory equipment; open hardware; open source; open source hardware; scale; balance; mass
Online: 27 April 2020 (02:59:34 CEST)
This study provides designs for a low-cost, easily replicable open source lab-grade digital scale that can be used as a precision balance. The design is such that it can be manufactured for use in most labs throughout the world with open source RepRap-class material extrusion-based 3-D printers for the mechanical components and readily available open source electronics including the Arduino Nano. Several versions of the design were fabricated and tested for precision and accuracy for a range of load cells. The results showed the open source scale was found to be repeatable within 0.1g with multiple load cells, with even better precision (0.01g) depending on load cell range and style. The scale tracks linearly with proprietary lab-grade scales, meeting the performance specified in the load cell data sheets, indicating that it is accurate across the range of the load cell installed. The smallest loadcell tested(100g) offers precision on the order of a commercial digital mass balance. The scale can be produced at significant cost savings compared to scales of comparable range and precision when serial capability is present. The cost savings increase significantly as the range of the scale increases and are particularly well-suited for resource-constrained medical and scientific facilities.
ARTICLE | doi:10.20944/preprints201812.0146.v1
Subject: Social Sciences, Business And Administrative Sciences Keywords: Corporate governance; business sustainability; multiple criteria decision-making (MCDM); decision-making trial and evaluation laboratory (DEMATEL); VIKOR; DEMATEL-based analytical network process (DANP); fuzzy set theory
Online: 12 December 2018 (12:43:40 CET)
While the importance of corporate governance has been broadly acknowledged in global financial markets and academic research, how to devise a practical evaluation system is relatively unexplored. This paper attempts to refine the Corporate Governance Evaluation System (CGES), constructed by the Taiwan Stock Exchange (TWSE) since 2014. The current CGES has several debatable issues in its complicated design (e.g., it comprises over 80 indicators in different types). To resolve those issues, this study invited ten senior domain experts (including several CEOs of financial holding companies) to retrieve 13 essential criteria from the CGES in four dimensions. And this study integrates several multiple criteria decision-making (MCDM) methods (i.e., Decision-making trial and evaluation laboratory (DEMATEL), modified VIKOR, DEMATEL-based analytical network process (DANP)) and the fuzzy evaluation technique to rank the exemplary companies. The obtained ranking is consistent with the one released from the CGES in 2017. This study conducted additional experiments to ensure the robustness of the findings. The newly devised model not only supports the ranking decisions but also provides a managerial guidance for companies to pursue systematic improvements. These findings enrich the understanding of corporate governance and contribute to gaining business sustainability for financial holding companies.
ARTICLE | doi:10.20944/preprints201904.0207.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: 3-D printing; additive manufacturing; biomedical equipment; biomedical engineering; centrifuge; design; distributed manufacturing; laboratory equipment; open hardware; open source; open source hardware; medical equipment; medical instrumentation; scientific instrumentation
Online: 18 April 2019 (08:03:58 CEST)
Centrifuges are commonly required devices in medical diagnostics facilities as well as scientific laboratories. Although there are commercial and open source centrifuges, costs of the former and required electricity to operate the latter, limit accessibility in resource-constrained settings. There is a need for low-cost, human-powered, verified and reliable lab-scale centrifuge. This study provides the designs for a low-cost 100% 3-D printed centrifuge, which can be fabricated on any low-cost RepRap-class fused filament fabrication (FFF) or fused particle fabrication (FPF)-based 3-D printer. In addition, validation procedures are provided using a web camera and free and open source software. This paper provides the complete open source plans including instructions for fabrication and operation for a hand-powered centrifuge. This study successfully tested and validated the instrument, which can be operated anywhere in the world with no electricity inputs obtaining a radial velocity of over 1750rpm and over 50N of relative centrifugal force. Using commercial filament the instrument costs about US$25, which is less than half of all commercially available systems; however, the costs can be dropped further using recycled plastics on open source systems for over 99% savings. The results are discussed in the contexts of resource-constrained medical and scientific facilities.
ARTICLE | doi:10.20944/preprints201804.0314.v1
Subject: Social Sciences, Microeconomics And Decision Sciences Keywords: urban freight transport; city logistics; decision making process; multi-actor decision support; Multi-Criteria Decision Analysis; MCDA; Analytic Hierarchy Process; AHP; Decision Making Trial and Evaluation Laboratory Method; DEMATEL
Online: 24 April 2018 (09:19:37 CEST)
Urban areas are centres of business and innovation. Freight transport is indispensable for the proper functioning of any modern urban society. Urban areas can’t function without an appropriate freight transport system, due to the need to replenish stocks of food and other goods in retail shops. The complexity of the decisions concerning implementation of measures to improve the movement of goods in the city requires tools designed to support this process. The purpose of this article is to introduce the possibility of applying the Analytic Hierarchy Process (AHP) as well as the Decision Making Trial and Evaluation Laboratory Method (DEMATEL) in choosing a set of measures and in analysing in the field of distribution logistics, which will help to solve the delivery problems and streamline the cargo flows in Szczecin, in the context of sustainable development.