bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method for leakage measurement in the recirculation path of a hermetic pump
Authors: Chaburko P , Kuznetsov A 
Published: April 2020

Abstract
The article is devoted to the measurement of leakage in the recirculation path of a hermetic pump. The field of application of hermetic pumps is described. The mathematical model used in computer simulation and the mesh conditions are given. The results of the numerical modeling and the theoretical calculation are presented. The graph of the dependence of the leakage in the recirculation path on the pump head is shown. The scalar scenes of velocities and pressures in the c path are given.
Development and research of a borehole centrifugal pump stage
Authors: Cheremushkin V , Lomakin V , Kalin N , Trulev A 
Published: April 2020

Abstract
This article is devoted to the model of a borehole centrifugal pump developed at the Department of Hydraulics of Bauman Moscow State Technical University. A universal layout has been developed for testing the stages of pumps of this type in a certain range of parameters. The article describes the mathematical model used. A comparison of numerical and field experiments is given. A problem has been identified when comparing their results.
Morphological caste differences in primitively eusocial insects: the Van der Vecht organ ofMischocyttaruspaper wasps
Authors: de Souza André Rodrigues , Baptista Camila Folly , Santos Eduardo Fernando , da Silva Rafael Carvalho , da Silva Prato Amanda , Antonialli-Junior William , Pereira Soares Eva Ramona , Barbosa Bruno Corrêa , do Nascimento Fábio Santos , Lino-Neto José 
Published: April 2020

AbstractNests of independent-founding primitively eusocial paper wasps are founded by one or a few females. Before worker emergence, foundresses must forage, sometimes leaving the nest unattended. Chemical defence - the application of ant repellent secretions of the Van der Vecht organ (VdVO) on the nest surface - allows brood protection when active defence is weak or not possible. After worker emergence, it is more likely that some wasps stay in the nest, so active nest defence may be more common. Given this constraint on the nest defence, selection for increasing the cuticular secretory area of the VdVO, to improve chemical defence, may be stronger in foundresses (queens) than in workers - morphological castes are hypothesized to evolve. We investigated the occurrence of morphological castes in the Neotropical paper wasp Mischocyttarus. Confirming our prediction, we found that in some (but not all) species, foundresses have a distinct increase in the secretory area of the VdVO in relation to workers; even though there is a strong overlap between caste phenotypes (incipient morphological castes). Implications of these findings for the evolution of morphological castes in primitively eusocial wasps are discussed.
Kidney manifestations of mild, moderate and severe coronavirus disease 2019: a retrospective cohort study
Authors: Hong Daqing , Long Lin , Wang Amanda Y , Lei Yu , Tang Yun , Zhao Jia Wei , Song Xiaofei , He Yanan , Wen Ergang , Zheng Ling , Li Guisen , Wang Li 
Published: April 2020

Abstract

Background
Coronavirus disease 2019 (COVID-19) is a pandemic that has affected more than 3 million patients globally. Previous data from Wuhan city showed that acute kidney injury (AKI), proteinuria and hematuria occurred frequently in patients with severe COVID-19. However, the prevalence of kidney injury in milder cases remains unclear.

Methods
This retrospective study included two major consecutive cohorts of COVID-19 patients in Sichuan Province. Baseline characteristics, laboratory data including renal function, proteinuria and dipstick hematuria, and other laboratory parameters were collected. A subgroup of patients was followed up for 2–4 weeks to evaluate the short-term outcome of renal impairment.

Results
Overall, 168 COVID-19-positive patients were included in the study. The majority of patients (79.7%) were diagnosed with mild or moderate disease. Half of patients presented with fever; however, in The Tibetan cohort, fever only occurred in 13.4% of patients. On hospital admission, proteinuria and dipstick hematuria were noted in 18.4% and 17.4% of patients, respectively, while AKI only occurred in one patient. Further analysis showed that severe or critical COVID-19 was associated with higher risk of proteinuria [relative risk (RR) 7.37, 95% confidence interval (CI) 2.45–22.18, P = 3.8 × 10−4] and dipstick hematuria (RR 8.30, 95% CI 2.69–25.56, P = 2.3 × 10−4). Proteinuria, dipstick hematuria, or the combination of proteinuria and hematuria could significantly predict severe or critical severe COVID-19.

Conclusions
Proteinuria and dipstick hematuria are not uncommon in patients with COVID-19 infection, especially in severe or critical cases.
Chest pain without obstructive coronary artery disease: a case series
Authors: Sidik Novalia P , McDermott Michael , McEntegart Margaret B , Berry Colin 
Published: April 2020

Abstract

Background
Ischaemic heart disease is a leading cause of mortality in women. Even in those without obstructive coronary artery disease (CAD), women with angina continue to have increased mortality. There are gender differences in prevalence of different pathophysiologies, including functional disorders such as microvascular and vasospastic angina.

Case summary
We describe four cases of angina in women with no obstructive CAD, in whom coronary function testing was performed. These four patients were diagnosed with disorders of coronary vasomotion, including vasospastic angina and different endotypes of microvascular angina.

Discussion
This case series highlights the different mechanisms of ischaemia in the absence of obstructive CAD. Patients with angina and no obstructive CAD classified by computed tomography coronary angiography may have myocardial ischaemia due to microvascular angina, vasospastic angina, or both. Conventional investigations risk under-diagnosing, and as a consequence under-treating, patients with these conditions. Coronary function testing, in the form of diagnostic guidewire-based tests and adjunctive acetylcholine provocation, has proven to be critical in the accurate diagnoses and appropriate management of these patients.
Unsupervised machine learning and prognostic factors of survival in chronic lymphocytic leukemia
Authors: Coombes Caitlin E , Abrams Zachary B , Li Suli , Abruzzo Lynne V , Coombes Kevin R 
Published: April 2020

Abstract

Objective
Unsupervised machine learning approaches hold promise for large-scale clinical data. However, the heterogeneity of clinical data raises new methodological challenges in feature selection, choosing a distance metric that captures biological meaning, and visualization. We hypothesized that clustering could discover prognostic groups from patients with chronic lymphocytic leukemia, a disease that provides biological validation through well-understood outcomes.

Methods
To address this challenge, we applied k-medoids clustering with 10 distance metrics to 2 experiments (“A” and “B”) with mixed clinical features collapsed to binary vectors and visualized with both multidimensional scaling and t-stochastic neighbor embedding. To assess prognostic utility, we performed survival analysis using a Cox proportional hazard model, log-rank test, and Kaplan-Meier curves.

Results
In both experiments, survival analysis revealed a statistically significant association between clusters and survival outcomes (A: overall survival, P = .0164; B: time from diagnosis to treatment, P = .0039). Multidimensional scaling separated clusters along a gradient mirroring the order of overall survival. Longer survival was associated with mutated immunoglobulin heavy-chain variable region gene (IGHV) status, absent Zap 70 expression, female sex, and younger age.

Conclusions
This approach to mixed-type data handling and selection of distance metric captured well-understood, binary, prognostic markers in chronic lymphocytic leukemia (sex, IGHV mutation status, ZAP70 expression status) with high fidelity.
Bridging the Accountability Gap
Authors: Jöbstl Hannes 
Published: April 2020

Abstract
During non-international armed conflict, war crimes often go unpunished in areas where state authorities are unable to enforce the law. While states are under a customary law obligation to investigate and prosecute war crimes committed on their territory or by their nationals, the Customary International Humanitarian Law Study of the International Committee of the Red Cross has not found that this obligation extends to armed non-state actors (ANSAs). Nevertheless, command responsibility requires the individual commander to punish their forces in case war crimes have been committed and a growing amount of state practice demanding similar commitments — both legally and politically — from these actors as such can be observed over the past two decades. Indeed, ANSAs routinely impose penal sanctions onto their subordinates and often establish judicial structures in order to do so. This article argues that whereas ANSAs should be under some form of obligation to ensure accountability, alternative solutions to makeshift courts and penal proceedings might be better suited to prevent impunity and maintain fair trial guarantees.
Dietary Intake, Hydration Status, and Body Composition of Three Belgian Military Groups
Authors: De Bry William , Mullie Patrick , D’Hondt Eva , Clarys Peter 
Published: April 2020

AbstractIntroductionMalnutrition, suboptimal hydration, and inadequate body composition can have negative consequences on soldiers’ performance and health. A recent consensus statement concerning “soldiers’ physical performance” points to the scarcity of data in specific military populations. Therefore, the aim of the present study was to assess and compare dietary intake, hydration status, and body composition of three military groups during their specific military training.Materials and MethodsEighty-five soldiers (ie, 21 in a qualification course to join the Special Forces [SF], 22 Infantrymen [Chasseurs Ardennais, CA], and 42 Recruits [REs]) participated in this 3- to 4-day study. Body mass was assessed before and after each study period. All soldiers self-reported their dietary intakes, from which energy and macronutrient intakes were calculated. In addition, their morning urine samples were collected daily to assess urine specific gravity (USG) as a measure of hydration status. Fat mass was estimated at the end of the study using bioelectrical impedance analysis.ResultsAll groups lost significant amounts of body mass (ie, mean losses ranging between 1.3 and 1.7 kg). Macronutrient intakes were not fully met in respect to the recommendations. Most notably, REs’ fat intake was high (ie, 42.3 [±1.6] energy percent [E%]), while their carbohydrate intake was low (ie, 44.5 [±2.1] E%). Furthermore, saturated fat intakes were high among all groups (ie, group means ranging between 13.6 and 21.4 E%). USG values indicated suboptimal hydration status was prevalent in all groups. Most noteworthy, for SF, only 5.4% of the USG values indicated optimal hydration. The average fat mass (%) for SF, CA, and RE was 11.2 (±3.1), 18.8 (±5.1), and 19.4 (±5.0), respectively.ConclusionThe present study showed that military men are not always adequately fed nor hydrated. These issues should be resolved by creating nutritional packages, and individual dietary and hydration strategies, all in function of military planning and weather conditions.
High HIV Incidence Among Men Who Have Sex With Men in 8 Chinese Cities: Results From a Trial
Authors: Huang Wenting , Wang Yehua , Lu Haidong , Wu Dan , Pan Stephen W , Tucker Joseph D , Tang Weiming 
Published: April 2020

Abstract

Background
In China, while the overall HIV prevalence has been decreasing within key populations, the epidemic among men who have sex with men (MSM) is still on the rise. This study aims to assess the HIV incidence rate and identify driving forces of HIV seroconversion among MSM in a closed cohort.

Methods
This study is a secondary analysis of a large trial of HIV testing promotion among Chinese MSM in 2016–2017. Sexual behaviors, HIV testing activities, and HIV serostatus were measured at baseline and follow-up every 3 months. HIV seroconversion in this study was defined as a self-reported HIV-positive test result. Participants who reported testing for HIV at least twice during different follow-up periods were included. Subgroup analysis and Cox regression were used to examine the correlates with HIV seroconversion.

Results
Overall, 347 participants were included in this study, with a mean age of 25.3 ± 6.1, and 71.2% were migrants. The sociodemographic characteristics of the included participants were similar to the rest of the participants in the trial (n = 1034); 7.2% (25/347) of participants seroconverted during the study period, resulting in an incidence rate of 15.56/100 person-years. In subgroup analysis, the HIV incidence rate was higher among migrants than nonmigrants (incidence rate ratio, 1.26; 95% confidence interval [CI], 0.47–3.87). In the time-dependent Cox regression model, bisexual MSM had a higher risk of contracting HIV than gay men (adjusted hazard ratio, 2.19; 95% CI, 1.02–4.72).

Conclusions
Our findings suggest a high HIV incidence rate among Chinese MSM. Further expansion of pre-exposure prophylaxis and other effective HIV prevention interventions are urgently needed.
The effect of zolpidem on memory consolidation over a night of sleep
Authors: Zhang Jing , Yetton Ben , Whitehurst Lauren N , Naji Mohsen , Mednick Sara C 
Published: April 2020

AbstractStudy Objectives: Nonrapid eye movement sleep boosts hippocampus-dependent, long-term memory formation more so than wake. Studies have pointed to several electrophysiological events that likely play a role in this process, including thalamocortical sleep spindles (12–15 Hz). However, interventional studies that directly probe the causal role of spindles in consolidation are scarce. Previous studies have used zolpidem, a GABA-A agonist, to increase sleep spindles during a daytime nap and promote hippocampal-dependent episodic memory. The current study investigated the effect of zolpidem on nighttime sleep and overnight improvement of episodic memories. Methods: We used a double-blind, placebo-controlled within-subject design to test the a priori hypothesis that zolpidem would lead to increased memory performance on a word-paired associates task by boosting spindle activity. We also explored the impact of zolpidem across a range of other spectral sleep features, including slow oscillations (0–1 Hz), delta (1–4 Hz), theta (4–8 Hz), sigma (12–15 Hz), as well as spindle–SO coupling. Results: We showed greater memory improvement after a night of sleep with zolpidem, compared to placebo, replicating a prior nap study. Additionally, zolpidem increased sigma power, decreased theta and delta power, and altered the phase angle of spindle–SO coupling, compared to placebo. Spindle density, theta power, and spindle–SO coupling were associated with next-day memory performance. Conclusions: These results are consistent with the hypothesis that sleep, specifically the timing and amount of sleep spindles, plays a causal role in the long-term formation of episodic memories. Furthermore, our results emphasize the role of nonrapid eye movement theta activity in human memory consolidation.
Multiple drivers of the COVID-19 spread: role of climate, international mobility, and region-specific conditions
Authors: Kubota Yasuhiro , Shiono Takayuki , Kusumoto Buntarou , Fujinuma Junichi 
Published: April 2020

AbstractThe novel Coronavirus Disease 2019 (COVID-19) has spread quickly across the globe. Here, we evaluated the role of climate (temperature and precipitation), region-specific susceptibility (BCG vaccination, malaria infection, and elderly population) and international traveller population (human mobility) in shaping the geographical patterns of COVID-19 cases across 1,055 countries/regions, and examined the sequential shift of multiple drivers of the accumulated cases from December, 2019 to April 12, 2020. The accumulated numbers of COVID-19 cases (per 1 million population) were well explained by a simple regression model. The explanatory power (R2) of the model increased up to > 70% in April 2020 as the COVID-19 spread progressed. Climate, host mobility, and host susceptibility largely explained the variance of the COVID-19 cases (per 1 million population), and their explanatory power improved as the pandemic progressed; the relative importance of host mobility and host susceptibility have been greater than that of climate. The number of days from outbreak onset showed greater explanatory power in the earlier stages of COVID-19 spread but rapidly lost its influence. Our findings demonstrate that the COVID-19 pandemic is deterministically driven by climate suitability, cross-border human mobility, and region-specific susceptibility. The present distribution of COVID-19 cases has not reached an equilibrium and is changing daily, especially in the Southern Hemisphere. Nevertheless, the present results, based on mapping the spread of COVID-19 and identifying multiple drivers of this outbreak trajectory, may contribute to a better understanding of the COVID-19 disease transmission risk and the measures against long-term epidemic.
Predicting mortality due to SARS-CoV-2: A mechanistic score relating obesity and diabetes to COVID-19 outcomes in Mexico
Authors: Bello-Chavolla Omar Yaxmehen , Bahena-López Jessica Paola , Antonio-Villa Neftali Eduardo , Vargas-Vázquez Arsenio , González-Díaz Armando , Márquez-Salinas Alejandro , Fermín-Martínez Carlos A. , Naveja J. Jesús , Aguilar-Salinas Carlos A. 
Published: April 2020

ABSTRACTBACKGROUNDThe SARS-CoV-2 outbreak poses challenge to healthcare systems due to high complication rates in patients with cardiometabolic diseases. Here, we identify risk factors and propose a clinical score to predict COVID-19 lethality, including specific factors for diabetes and obesity and its role in improving risk prediction.METHODSWe obtained data of confirmed and negative COVID-19 cases and their demographic and health characteristics from the General Directorate of Epidemiology of Mexican Ministry of Health. We investigated specific risk factors associated to COVID-19 positivity and mortality and explored the impact of diabetes and obesity on modifying COVID-19 related lethality. Finally, we built a clinical score to predict COVID-19 lethality.RESULTSAmong 177,133 subjects at May 18th, 2020, we observed 51,633 subjects with SARS-CoV-2 and 5,332 deaths. Risk factors for lethality in COVID-19 include early-onset diabetes, obesity, COPD, advanced age, hypertension, immunosuppression, and CKD; we observed that obesity mediates 49.5% of the effect of diabetes on COVID-19 lethality. Early-onset diabetes conferred an increased risk of hospitalization and obesity conferred an increased risk for ICU admission and intubation. Our predictive score for COVID-19 lethality included age ≥65 years, diabetes, early-onset diabetes, obesity, age <40 years, CKD, hypertension, and immunosuppression and significantly discriminates lethal from non-lethal COVID-19 cases (c-statistic=0.823).RESULTSHere, we propose a mechanistic approach to evaluate risk for complications and lethality attributable to COVID-19 considering the effect of obesity and diabetes in Mexico. Our score offers a clinical tool for quick determination of high-risk susceptibility patients in a first contact scenario.
ESTIMATING R0 OF SARS-COV-2 IN HEALTHCARE SETTINGS
Authors: Temime Laura , Gustin Marie-Paule , Duval Audrey , Buetti Niccolò , Crépey Pascal , Guillemot Didier , ThiéBaut Rodolphe , Vanhems Philippe , Zahar Jean-Ralph , Smith David R.M. , Opatowski Lulla 
Published: April 2020

ABSTRACTTo date, no specific estimate of R0 for SARS-CoV-2 is available for healthcare settings. Using inter-individual contact data, we highlight that R0 estimates from the community cannot translate directly to healthcare settings, with pre-pandemic R0 values ranging 1.3-7.7 in three illustrative healthcare institutions. This has implications for nosocomial Covid-19 control.
Prevalence of SARS-CoV-2 infection in previously undiagnosed health care workers at the onset of the U.S. COVID-19 epidemic
Authors: Barrett Emily S. , Horton Daniel B. , Roy Jason , Gennaro Maria Laura , Brooks Andrew , Tischfield Jay , Greenberg Patricia , Andrews Tracy , Jagpal Sugeet , Reilly Nancy , Blaser Martin J. , Carson Jeffrey L. , Panettieri Reynold A. 
Published: April 2020

AbstractImportanceHealthcare workers are presumed to be at increased risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection due to occupational exposure to infected patients. However, no epidemiological study has examined the prevalence of SARS-CoV-2 infection in a cohort of healthcare workers during the early phase of community transmission.ObjectiveTo determine the baseline prevalence of SARS-CoV-2 infection in a cohort of previously undiagnosed healthcare workers and a comparison group of non-healthcare workers.DesignProspective cohort studySettingA large U.S. university and two affiliated university hospitalsParticipants546 health care workers and 283 non-health care workers with no known prior SARS-CoV-2 infectionExposureHealthcare worker status and roleMain outcome(s) and measure(s)SARS-CoV-2 infection status as determined by presence of SARS-CoV-2 RNA in oropharyngeal swabs.ResultsAt baseline, 41 (5.0%) of participants tested positive for SARS-CoV-2 infection, of whom 14 (34.2%) reported symptoms. The prevalence of SARS-CoV-2 infection was higher among healthcare workers (7.3%) than in non-healthcare workers (0.4%), representing a 7.0% greater absolute risk (95% confidence interval for risk difference 4.7%, 9.3%). The majority of infected healthcare workers (62.5%) worked as nurses. Positive tests increased across the two weeks of cohort recruitment in line with rising confirmed cases in the hospitals and surrounding counties.Conclusions and relevanceIn a prospective cohort conducted in the early phases of community transmission, healthcare workers had a higher prevalence of SARS-CoV-2 infection than non-healthcare workers, attesting to the occupational hazards of caring for patients in this crisis. Baseline data reported here will enable us to monitor the spread of infection and examine risk factors for transmission among healthcare workers. These results will inform optimal strategies for protecting the healthcare workforce, their families, and their patients.Clinicaltrials.gov registration number:NCT04336215Key pointsQuestionAmong previously undiagnosed individuals, is the prevalence of SARS-CoV-2 infection higher in U.S. healthcare workers compared to non-healthcare workers in the early phase of the U.S. COVID-19 epidemic?FindingsThe prevalence of SARS-CoV-2 infection was 7.3% in healthcare workers and 0.4% in non-healthcare workers, representing 7.0% greater absolute risk in the former (95% confidence interval for risk difference 4.7%, 9.3%). Infections were most common among nursing staff.MeaningHealth care workers, particularly those with high levels of close patient contact, may be particularly vulnerable to SARS-CoV-2 infection. Additional strategies are needed to protect these critical frontline workers.