bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prolonged QT predicts prognosis in COVID‐19
Authors: Akhtar Zaki , Gallagher Mark M. , Yap Yee Guan , Leung Lisa W. M. , Elbatran Ahmed I. , Madden Brendan , Ewasiuk Victoria , Gregory Louise , Breathnach Aodhan , Chen Zhong , Fluck David S. , Sharma Sumeet 
Published: April 2021

AbstractBackgroundCoronavirus disease‐2019 (COVID‐19) causes severe illness and multi‐organ dysfunction. An abnormal electrocardiogram is associated with poor outcome, and QT prolongation during the illness has been linked to pharmacological effects. This study sought to investigate the effects of the COVID‐19 illness on the corrected QT interval (QTc).MethodFor 293 consecutive patients admitted to our hospital via the emergency department for COVID‐19 between 01/03/20 ‐18/05/20, demographic data, laboratory findings, admission electrocardiograph and clinical observations were compared in those who survived and those who died within 6 weeks. Hospital records were reviewed for prior electrocardiograms for comparison with those recorded on presentation with COVID‐19.ResultsPatients who died were older than survivors (82 vs 69.8 years, p < 0.001), more likely to have cancer (22.3% vs 13.1%, p = 0.034), dementia (25.6% vs 10.7%, p = 0.034) and ischemic heart disease (27.8% vs 10.7%, p < 0.001). Deceased patients exhibited higher levels of C‐reactive protein (244.6 mg/L vs 146.5 mg/L, p < 0.01), troponin (1982.4 ng/L vs 413.4 ng/L, p = 0.017), with a significantly longer QTc interval (461.1 ms vs 449.3 ms, p = 0.007). Pre‐COVID electrocardiograms were located for 172 patients; the QTc recorded on presentation with COVID‐19 was longer than the prior measurement in both groups, but was more prolonged in the deceased group (448.4 ms vs 472.9 ms, pre‐COVID vs COVID, p < 0.01). Multivariate Cox‐regression analysis revealed age, C‐reactive protein and prolonged QTc of >455 ms (males) and >465 ms (females) (p = 0.028, HR 1.49 [1.04‐2.13]), as predictors of mortality. QTc prolongation beyond these dichotomy limits was associated with increased mortality risk (p = 0.0027, HR 1.78 [1.2‐2.6]).ConclusionQTc prolongation occurs in COVID‐19 illness and is associated with poor outcome.
Attitudes towards Indian English among young urban professionals in Hyderabad, India
Authors: Maxwell Olga , Diskin‐Holdaway Chloé , Loakes Debbie 
Published: April 2021

AbstractDespite extensive work on the description of Indian English(es), only limited attention has been paid to attitudes towards the variety among its speakers. This paper reports on semi‐structured interviews eliciting language attitudes with 32 educated young students and professionals in Hyderabad, India. Results reveal that Indian English is occupying an increasingly legitimate position within the popular consciousness, and that there is an increasing sense of ownership of a supra‐local or pan‐dialectal ‘Indian English’. There is an expressed desire for Indian English to continue to expand, and to be accepted as one of the authentic languages of India. The participants exhibited relatively high levels of linguistic security, and while a certain ‘nostalgia’ for British English was retained by some, Indian English appears to be emerging as an authentic carrier of Indian identity.
To compare the effect of sea buckthorn and silver sulfadiazine dressing on period of wound healing in patients with second‐degree burns: A randomized triple‐blind clinical trial
Authors: Abdullahzadeh Mehrdad , Shafiee Saeed 
Published: April 2021

AbstractBurn injuries can be associated with the incidence of disability and death, yet their management remains a costly difficult problem. We conducted this clinical trial to evaluate the period of wound healing with sea buckthorn dressings for the second‐degree burns and compare the results with 1% silver sulfadiazine (SSD) dressings. This randomized triple‐blind clinical trial was conducted in a hospital in Isfahan, Iran. Fifty‐five patients suffering second‐degree burns were recruited through convenient sampling and randomly divided into two groups and treated with either sea buckthorn cream or 1% SSD. Wound dressings were done until complete wound healing was attained. The process of healing burns was monitored using the Bates‐Jensen Wound Assessment Tool; complete healing was determined by using the standard burn healing checklist. It was deduced that the period of healing second‐degree burns in the group treated with sea buckthorn cream was shorter than the group treated with 1% SSD (p < 0.001). The results demonstrated the greater clinical efficacy of sea buckthorn cream over 1% SSD for healing second‐degree burns. It was concluded that using sea buckthorn dressing by reducing the period of wound healing can shorten the course of treatment of second‐degree burns as well as reduce the burden of care in health care services.
Mini-Channel Liquid Cooling System for Improving Heat Transfer Capacity and Thermal Uniformity in Battery Packs for Electric Vehicles
Authors: Li Congbo , Li Yongsheng , Srinivaas Sanjay , Zhang Jinwen , Qu Shiyang , Li Wei 
Published: April 2021

Abstract
Temperature is a significant factor affecting performance and safety of energy storage systems such as battery packs. How to design a reliable battery thermal management system (BTMS) is still a hot issue at present. Most of the past researches have focused on methods of reducing temperature rise. This paper mainly studies how to reduce the temperature deviation of the battery pack while ensuring heat dissipation conditions. This paper designs a mini-channel liquid cooling BTMS with a side cover to improve heat transfer capacity and thermal uniformity in battery packs. By analyzing different side cover materials, cooling water temperature, and water channel structure, the influence of different parameters on battery heat dissipation and uniformity is obtained. The main findings are: (1) the presence of the side cover can effectively reduce the maximum temperature and temperature deviation, and the material with high thermal conductivity is more likely to dissipate heat, (2) The increase of cooling water inlet temperature can improve temperature uniformity, and (3) When the cross-sectional area is fixed, as the channel depth increases, the temperature deviation gradually decreases.
The Development of a Highly Durable Fe-N-C Electrocatalyst With Favorable Carbon Nanotube Structures for the Oxygen Reduction in PEMFCs
Authors: Shen Shuiyun , Ren Ziwen , Xiang Silei , Chen Shiqu , Tan Zehao , Li Huiyuan , Zhang Junliang 
Published: April 2021

Abstract
Proton exchange membrane fuel cell (PEMFC) is a crucial route for energy saving, emission reduction, and the development of new energy vehicles because of its high power density, high energy density, as well as the low operating temperature which corresponds to fast starting and power matching. However, the rare and expensive Pt resource greatly hinders the mass production of the fuel cell, and the development of highly active and durable non-precious metal catalysts toward the oxygen reduction reaction (ORR) in the cathode is considered to be the ultimate solution. In this article, a highly active and durable Fe-N-C catalyst was facilely derived from metal-organic framework (MOF) materials, and a favorable structure of carbon nanotubes (CNTs) was formed, which accounts for a desired good durability. The as-optimized catalyst has a half-wave potential of 0.84 V for the ORR, which is comparable to that of commercial Pt/C. More attractively, it has good stabilities both in rotating disk electrode (RDE) and single-cell tests, which provides a large practical application potential in the replacement of Pt catalyst as the ORR electrocatalyst in fuel cells.
Effect of ZrO2 Nanoparticles and Mechanical Milling on Microstructure and Mechanical Properties of Al–ZrO2 Nanocomposites
Authors: Aktaş Sinem , Anıl Diler Ege 
Published: April 2021

AbstractNano-aluminum powders and nano-ZrO2 reinforcement particles were mechanically milled and hot-pressed to produce Al–ZrO2 nanocomposites. Microstructure and mechanical properties of Al–ZrO2 nanocomposites were investigated using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses and by performing hardness and compression testing. Uniform particle distribution was obtained up to 3 wt% of nano-ZrO2 particles using nano-sized aluminum powders as matrix powders and by applying a mechanical milling process. As the nano-ZrO2 reinforcement particles were uniformly distributed in the matrix, the relative density of the Al–ZrO2 nanocomposites increased up to 3 wt% nano-ZrO2 particles with an increase in milling time; on the other hand, the relative density decreased and the porosity increased with high-weight fractions (&gt;3 wt%) of nano-ZrO2 particles due to the negative combined effect of less densification and an increase in the number of particle clusters. The hardness and compressive strength of the Al–ZrO2 nanocomposites improved despite increased porosity. However, the compressive strength of Al–ZrO2 nanocomposites with a high amount (&gt;3 wt%) of nano-ZrO2 particles began to decrease due to the negative combined effect of the less densification of the powder particles and the clustering of nano-ZrO2 reinforcement particles. The brittle-ductile fracture occurred in the Al–ZrO2 nanocomposites.
Experimental Investigation of Direct Steam Generation Dynamics in Solar Fresnel Collectors
Authors: Mokhtar Marwan , Zahler Christian , Stieglitz Robert 
Published: April 2021

Abstract
Direct steam generation (DSG) is a technology used to produce steam from a solar concentrated thermal plant directly in the solar field without the use of an intermediate steam generator. This technology is attractive due to economic considerations but is technically challenging. In this brief, the results of an experimental study of DSG dynamics are presented. The study provides a detailed description of these effects supported by experimental results and suggests ways to coping with them.
Three-Dimensional Elastoplastic Contact Analysis of Rough Surface Considering a Micro-Scale Effect
Authors: You Shengyu , Tang Jinyuan , Wen Yuqin 
Published: April 2021

Abstract
The micro-surface asperity scale of grinding metal parts is within several microns. When two grinding surfaces are in contact, the unevenness of the plastic deformation of the asperities at the micro-scale leads to greater plastic hardening strength of the material. The results of the nano-indentation experiment conducted in this paper confirmed this phenomenon. Based on conventional mechanism-based strain gradient (CMSG) plasticity theory, the micro-scale plastic constitutive equation of materials is given and then is verified by the nano-indentation experiment. Finite element software abaqus and the user-defined element (UEL) subroutine are used to build three-dimensional rough surface elastoplastic contact models. By calculating the grinding rough surface contact in the macro-scale constitutive model based on J2 theory and in the CMSG plasticity constitutive model, the influence law of plastic micro-scale effect on contact performance is obtained.
Design of Contact-Aided Compliant Flexure Hinge Mechanism Using Superelastic Nitinol
Authors: Ping Zhongyuan , Zhang Tianci , Zhang Chi , Liu Jianbin , Zuo Siyang 
Published: April 2021

Abstract
This paper presents a novel miniature contact-aided compliant mechanism (CCM) that includes flexure hinges and contact-aided structures. This continuum mechanism comprises a nickel–titanium alloy (Nitinol) tube with CCM cut via laser micromachining and actuated using wires bending from −80 deg to +80 deg in four directions. The proposed CCM has the following merits: perfect capacity for deflection around the centroid, a self-backbone, and improved torsional as well as tensile strengths. Further, it is pre-assembled. First, kinematic and static models are used to predict the bending behavior of the mechanism. Thereafter, the maximum strain is evaluated using finite element analysis (FEA) then compared with the static models. Finally, the performances of the mechanism are characterized by experiments. The results validate the proposed models and demonstrate that the torsional and tensile strengths of the proposed CCM increased by more than 100% and 30%, respectively, compared with those of conventional non-CCMs with a similar fatigue life. Moreover, with the integrated forceps and probe, the proposed mechanism can achieve object transfer and square trajectory scanning of the targeted location. These experimental results demonstrate the potential clinical value of the proposed mechanism and provide important insights into the design of long and flexible instruments for endoscopic surgery.
The burgeoning reach of animal culture
Authors: Whiten Andrew 
Published: April 2021

We are not alone
Before the mid-20th century, it was generally assumed that culture, behavior learned from others, was specific to humans. However, starting with identification in a few species, evidence that animals can learn and transmit behaviors has accumulated at an ever-increasing pace. Today, there is no doubt that culture is widespread among animal species, both vertebrates and invertebrates, marine and terrestrial. Whiten reviews evidence for animal culture and elaborates on the wide array of forms that such culture takes. Recognizing that other species have complex and varied culture has implications for conservation and welfare and for understanding the evolution of this essential component of animal societies, including our own.

Science
, this issue p.
eabe6514
Low-energy sweeteners and body weight: a citation network analysis
Authors: Normand Mie , Ritz Christian , Mela David , Raben Anne 
Published: April 2021

ObjectiveReviews on the relationship of low-energy sweeteners (LES) with body weight (BW) have reached widely differing conclusions. To assess possible citation bias, citation analysis was used to quantify the relevant characteristics of cited articles, and explore citation patterns in relation to review conclusions.DesignA systematic search identified reviews published from January 2010 to March 2020. Different characteristics (for example, type of review or research, journal impact factor, conclusions) were extracted from the reviews and cited articles. Logistic regression was used to estimate likelihood of articles with particular characteristics being cited in reviews. A qualitative network analysis linked reviews sub-grouped by conclusions with the types of articles they cited.Main outcome measures(OR; 95% CI) for likelihood that articles with particular characteristics were cited as evidence in reviews.ResultsFrom 33 reviews identified, 183 different articles were cited (including other reviews). Narrative reviews were 62% less likely to be cited than systematic reviews with meta-analysis (OR 0.38; 0.16 to 0.86; p=0.03). Likelihood of being cited was higher for evidence on children than adults (OR 2.27; 1.59 to 3.25; p<0.0001), and with increased journal impact factor (OR 1.15; 1.00 to 1.31; p=0.04). No other factors were statistically significant in the main analysis, and few factors were significant in subgroup analyses. Network analysis showed that reviews concluding a beneficial relationship of LES with BW cited mainly randomised controlled trials, whereas reviews concluding an adverse relationship cited mainly observational studies.ConclusionsOverall reference to the available evidence across reviews appears largely arbitrary, making citation bias likely. Differences in the conclusions of individual reviews map onto different types of evidence cited. Overall, inconsistent and selective use of the available evidence may account for the diversity of conclusions in reviews on LES and BW.Trial registration numberPrior to data analysis, the protocol was registered with the Open Science Framework (https://osf.io/9ghws).
SARS-CoV-2 population-based seroprevalence studies in Europe: a scoping review
Authors: Grant Rebecca , Dub Timothée , Andrianou Xanthi , Nohynek Hanna , Wilder-Smith Annelies , Pezzotti Patrizio , Fontanet Arnaud 
Published: April 2021

ObjectivesWe aimed to review SARS-CoV-2 seroprevalence studies conducted in Europe to understand how they may be used to inform ongoing control strategies for COVID-19.DesignScoping review of peer-reviewed publications and manuscripts on preprint servers from January 2020 to 15 September 2020.Primary measureSeroprevalence estimate (and lower and upper CIs). For studies conducted across a country or territory, we used the seroprevalence estimate and the upper and lower CIs and compared them to the total number of reported infections to calculate the ratio of reported to expected infections.ResultsWe identified 23 population-based seroprevalence studies conducted in Europe. Among 12 general population studies, seroprevalence ranged from 0.42% among residual clinical samples in Greece to 13.6% in an area of high transmission in Gangelt, Germany. Of the eight studies in blood donors, seroprevalence ranged from 0.91% in North-Western Germany to 23.3% in a high-transmission area in Lombardy region, Italy. In three studies which recruited individuals through employment, seroprevalence ranged from 0.5% among factory workers in Frankfurt, Germany, to 10.2% among university employees in Milan, Italy. In comparison to nationally reported cases, the extent of infection, as derived from these seroprevalence estimates, is manyfold higher and largely heterogeneous.ConclusionExposure to the virus in Europe has not reached a level of infection that would prevent further circulation of the virus. Effective vaccine candidates are urgently required to deliver the level of immunity in the population.
Psychological and occupational impact of the COVID-19 pandemic on UK surgeons: a qualitative investigation
Authors: Al-Ghunaim Tmam Abdulaziz , Johnson Judith , Biyani Chandra Shekhar , O’Connor Daryl 
Published: April 2021

BackgroundThe COVID-19 pandemic represents the greatest biopsychosocial emergency the world has faced for a century. The pandemic has changed how individuals live and work, and in particular, frontline healthcare professionals have been exposed to alarming levels of stress.ObjectiveThe aim of this study was to understand the professional and personal effects of COVID-19 pandemic on surgeons working in the UK National Health Service (NHS).SettingSurgical departments in the NHS.DesignBetween May and July 2020, as part of an ongoing study, we asked surgeons two open-ended questions: ‘What challenges are the COVID-19 crisis currently presenting to you in your work and home life?’ and ‘How is this stress affecting you personally?’ Thematic analysis was used for the qualitative data. Responses to the second question were also categorised into four groups reflecting valence: positive, neutral, mildly negative and strongly negative.ResultsA total of 141 surgeons responded to the survey and the results indicated that 85.8% reported that they were generally negatively affected by the COVID-19 pandemic, of which 7.8% were strongly affected in a negative way. Qualitative thematic analysis identified four key themes from responses relating to the impact of the pandemic: (1) changing and challenging work environment as a result of COVID-19; (2) challenges to professional life and development; (3) management of change and loss in the respondents’ personal lives; (4) emotional and psychological impacts.ConclusionThe results highlighted the substantial emotional and psychological effects of the COVID-19 pandemic on surgeons’ mental health, particularly in relation to fear and anxiety, loss of motivation, low mood, stress and burnout. There is an urgent need for workplace support and mental health interventions to help surgeons cope with the difficulties they face during the ongoing COVID-19 pandemic.
Sexual intercourse before exercise has a detrimental effect on lower extremity muscle strength in men
Authors: Kirecci Sinan Levent , Albayrak Ahmet Tevfik , Yavuzsan Abdullah Hizir , Yesildal Cumhur , Ilgi Musab , Kutsal Cemil 
Published: April 2021

AbstractIntroductionThe question of whether sexual intercourse can harm athletic performance is a long-debated topic since first sport competitions were invented. Therefore, due to the lack of solid evidence, we aimed to evaluate the effects of sexual intercourse on muscle training performance.Materials and methodsPhysically and sexually active, 50 men (age=29.3±1.14 years) were enrolled in the study. Participants completed three weight training sessions and all sessions were at the same time of the day. The maximum weight was adjusted in the first session. In the second and third sessions, they performed five repetitions of the squat with their maximum weight for each set with a total of five sets after participating in and abstaining from sexual intercourse the night before, respectively. The duration of sexual intercourse was measured with a stopwatch.ResultsThe mean duration of sex was measured to be 13.8±3.61 min. Furthermore, the mean lifted weight before sex was calculated to be 109.4±11.41 kg and the mean lifted weight after sex was calculated to be 107±11.05 kg. According to obtained data, sexual intercourse has a significant detrimental effect on maximum weight in squat training (p=0001).ConclusionResults demonstrate that sexual intercourse within 24 hours before exercise have detrimental effect on lower extremity muscle force, which suggests that restricting sexual activity before a short-term activity may be necessary.
Immediate consequences and solutions used to maintain medical education during the COVID-19 pandemic for residents and medical students: a restricted review
Authors: Chasset François , Barral Matthias , Steichen Olivier , Legrand Anne 
Published: April 2021

AbstractBackgroundThe COVID-19 outbreak has dramatically impacted medical education, both bedside and academic teaching had to be adapted to comply with the reorganisation of care and social distancing measures.ObjectivesTo overview the impact of the pandemic on medical education, including the pedagogical responses adopted and their assessment by medical students and residents.Material and methodsThis restricted systematic review was performed using Rayyan QCRI, to select observational or interventional articles and field experience reports assessing the impact of the COVID-19 pandemic on medical education for medical students and residents. Study design, study population, geographical origin, use of an educational tools (including softwares and social media), their type and assessment, were recorded. For studies evaluating a specific tool the Medical Education Research Study Quality Instrument (MERSQI) was used to assess study quality.ResultsThe literature search identified 1480 references and 60 articles were selected. Most articles focused on residents (41/60; 69%), and half (30/60; 50%) involved surgical specialties. Online courses were the most frequently used pedagogical tool (52/60; 88%). Simulation tools were used more frequently in articles involving surgical specialties (15/29; 52%) compared with medical specialties (2/14; 12%) (p=0.01). Only four studies reported the assessment of pedagogical tools by medical students, their MERSQI scores ranged from 5.5/18 to 9.0/18.ConclusionMedical education was highly impacted by the COVID-19 pandemic particularly in surgical specialties. Online courses were the most frequently attempted solution to cope with social distancing constraints. Medical students' assessment of pedagogical tools was mostly positive, but the methodological quality of those studies was limited.