bluuebunny/crossref_metadata_2025 huggingface dataset:
Bias in assessment: name, reframe, and check in
Authors: Fainstad Tyra L. , McClintock Adelaide H. , Yarris Lalena M.
Published: March 2021

Cognitive bias permeates almost every learner assessment in medical education. Assessment bias has the potential to affect a learner's education, future career and sense of self‐worth. Decades of data show that there is little educators can do to overcome bias in learner assessments. Using in‐group favouritism as an example, we offer an evidence‐based, three‐step solution to understand and move forward with cognitive bias in assessment: (1) Name: a simple admission about the presence of inherent bias in assessment, (2) Reframe: a rephrasing of assessment language to shed light on the assessor's subjectivity and (3) Check‐in: a chance to ensure learner understanding and open lines of bidirectional communication. This process is theory‐informed and based on decades of educational, sociological and psychological literature; we offer it as a logical first step towards a much‐needed paradigm shift towards addressing bias in learner assessment.
Benefits of lower neonatal platelet transfusion thresholds
Authors: Hasan Rida , Saifee Nabiha H.
Published: March 2021

Key Ideas

Degree of thrombocytopenia is not a predictor of bleeding risk in neonates, yet most platelet transfusions are given prophylactically in non‐bleeding premature infants.

Recent data support a lower platelet transfusion threshold of 25 × 109/L in non‐bleeding premature neonates and indicate that higher transfusion thresholds may be associated with harm including increased risk of death and bleeding.

The mechanism of increased adverse events with higher platelet transfusion threshold is unknown, but considerations include adult platelets disrupting the neonatal hemostatic balance of hypoactive platelets in a hypercoagulable and fragile environment and having a pro‐inflammatory effect.
Apparatus Named After Our Academic Ancestors – V
Authors: Greenslade Thomas B.
Published: March 2021

In the museum wing of the Greenslade house is a clock with a two-second pendulum about one meter long (Fig. 1). This ticks once per second, and every time it passes through dead center it completes an electrical circuit. When I came to Kenyon in 1964, this system was used to send signals to a series of telegraph relays, which ticked once per second. Students in the first-year laboratory used beats between the ticking sec-onds and the oscillation of the pendula they were studying in an era when stopwatches were expensive. This clock inspired me to write this article about physicists who have pendula named after them: Christiaan Huygens, Lionel Wilberforce, Henry Kater, Benjamin Robins, Leon Foucault, and Hugh Blackburn.
Standing Vertical Jumps – Sports Physics with a Smartphone
Authors: Darmendrail L. , Müller A.
Published: March 2021

The standing vertical jump (SVJ) is a classical topic in Newtonian mechanics (Fig. 1). Although the topic has also been treated by others (other terms used are “standing high jump” or “squat jump”), the present paper shows how a smartphone can be used to capture video of a jump and determine the jump height. A crucial assumption often made in analysis of the SVJ is the constancy of force or acceleration during the stand-up phase. This is, however, not a trivial assumption in view of the changing geometrical configuration of the legs during standing up. We show that indeed the acceleration of the center of mass is nearly constant during the stand-up phase of the jump, a finding that has so far only been possible by much more expensive measurements (force plates).
An Analysis of Shadows Made from Sunlight Reflected by a Curved Surface
Authors: Tripathi Swapnil
Published: March 2021

Shadows produced by sunlight reflected from convex surfaces can be very well defined. This article provides an explanation for this phenomenon as well as a demonstration/lab activity for students to investigate properties of shadows made from sunlight reflected by a curved surface.
Motivating Premedical Students to Get Interested in Physics
Authors: Shlyonsky Vadim
Published: March 2021

Physics teachers around the world are trying to create classroom environments that would allow life science students to be more intrinsically motivated in their work. These efforts include, among others, matching classroom activities to students’ interests as well as structurally variable activities to match different student abilities. While physics instruction at the Université libre de Bruxelles also strives to make classes more relevant for life science students, two stimulation approaches will be presented here in detail. These include the in-class motivation using historical examples of physicians’ role in physics development and the small group work outside of class on physics problems that have engaging, motivating, and challenging biomedical headings.
Conventional Testing Produces Submaximal Values for Oxygen Uptake in Elite Runners
Authors: Beltrami Fernando G. , Noakes Timothy D.
Published: March 2021

Purpose: This study aimecd to investigate whether elite athletes could reach higher values of maximal oxygen uptake () during a decremental exercise test in comparison with a traditional incremental test, as recently demonstrated in trained individuals. Methods: Nine male runners (age 25.8 [5.1] y, season best 10-km time 31:19 [1:50]) performed, on different days, 3 maximal uphill (5% grade) running exercise tests in fixed order: an incremental test (INC1), a V-shape exercise test (where speed started at 0.5 km·h−1 higher than the top stage finished during INC1 and was slowly decreased during 5.5 min, when it was again increased in similar fashion to the INC tests), and a final incremental test (INC2). Results: during the V-shape exercise test was higher than during INC1 (6.3% [3.0%], P = .01), although running speed was lower (16.6 [1.7] vs 17.9 [1.6] km·h−1, P = .01). Performance was similar between INC1 and INC2, but during INC2 was higher than INC1 (P < .001). During the V-shape exercise test, 5 participants reached the incremental part of the test, but did not increase (, P = .67), despite higher running speed (approximately 1.1 km·h−1, P < .01). Heart rate, pulmonary ventilation, breathing rate, and respiratory exchange ratio measured at were not different between tests. Conclusion: A decremental exercise test of sufficient intensity can produce higher than a traditional incremental test, even in elite athletes, and this is maintained during a subsequent incremental test.
A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains
Authors: Van Ginneken M. , Goderis S. , Artemieva N. , Debaille V. , Decrée S. , Harvey R. P. , Huwig K. A. , Hecht L. , Yang S. , Kaufmann F. E. D. , Soens B. , Humayun M. , Van Maldeghem F. , Genge M. J. , Claeys P.
Published: March 2021

Dust from Antarctica reveals a new type of meteoritic event that vaporized the surface of the ice sheet ~430 ka ago.
Ancient Xinjiang mitogenomes reveal intense admixture with high genetic diversity
Authors: Wang Wenjun , Ding Manyu , Gardner Jacob D. , Wang Yongqiang , Miao Bo , Guo Wu , Wu Xinhua , Ruan Qiurong , Yu Jianjun , Hu Xingjun , Wang Bo , Wu Xiaohong , Tang Zihua , Niyazi Alipujiang , Zhang Jie , Chang Xien , Tang Yunpeng , Ren Meng , Cao Peng , Liu Feng , Dai Qingyan , Feng Xiaotian , Yang Ruowei , Zhang Ming , Wang Tianyi , Ping Wanjing , Hou Weihong , Li Wenying , Ma Jian , Kumar Vikas , Fu Qiaomei
Published: March 2021

The 237 ancient mitochondrial genomes from Xinjiang reveal highly admixed populations from the Bronze Age to Historical Era.
Processed foods drive intestinal barrier permeability and microvascular diseases
Authors: Snelson Matthew , Tan Sih Min , Clarke Rachel E. , de Pasquale Cassandra , Thallas-Bonke Vicki , Nguyen Tuong-Vi , Penfold Sally A. , Harcourt Brooke E. , Sourris Karly C. , Lindblom Runa S. , Ziemann Mark , Steer David , El-Osta Assam , Davies Michael J. , Donnellan Leigh , Deo Permal , Kellow Nicole J. , Cooper Mark E. , Woodruff Trent M. , Mackay Charles R. , Forbes Josephine M. , Coughlan Melinda T.
Published: March 2021

This study shows how highly processed foods can cause innate immune inflammation that promotes chronic microvascular disease.
A cellular platform for the development of synthetic living machines
Authors: Blackiston Douglas , Lederer Emma , Kriegman Sam , Garnier Simon , Bongard Joshua , Levin Michael
Published: March 2021

Amphibian embryonic explants generate motile living machines.
A Novel Auxiliary Agarolytic Pathway Expands Metabolic Versatility in the Agar-Degrading Marine Bacterium Colwellia echini A3
T
Authors: Pathiraja Duleepa , Christiansen Line , Park Byeonghyeok , Schultz-Johansen Mikkel , Bang Geul , Stougaard Peter , Choi In-Geol
Published: March 2021

Colwellia echini
A3
T
is an example of how the gain of gene(s) can lead to the evolutionary expansion of agar-specific polysaccharide utilization loci (PUL).
C. echini
A3
T
encodes two α-agarases in addition to the core β-agarolytic enzymes in its agarolytic PUL. Among the agar-degrading CAZymes identified so far, only a few α-agarases have been biochemically characterized.
Genome Sequence of a SARS-CoV-2 Strain from a COVID-19 Clinical Sample from the Khagrachari District of Bangladesh
Authors: Hoq M. Imranul , Bhuiyan Robiul Hasan , Rahman M. Khondakar Raziur , Hossen Imam , Rudra Sajib , Hossain M. Arif , Paul Shanta , Faruq M. Omer , Faruque Mohammad Omar , Masud H. M. Abdullah Al
Published: March 2021

This study describes the genome sequence of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain detected in the nasopharyngeal swab sample of a coronavirus disease 2019 (COVID-19) patient from the southeastern Khagrachari District of Bangladesh.
Draft Genome Sequences of
Aspergillus
and
Penicillium
Species Isolated from the International Space Station and Crew Resupply Vehicle Capsule
Authors: Blachowicz Adriana , Singh Nitin Kumar , Wood Jason M. , Debieu Marilyne , O’Hara Niamh B. , Mason Christopher E. , Venkateswaran Kasthuri
Published: March 2021

The draft whole-genome sequences (WGS) of 30 fungal strains isolated from the International Space Station and belonging to the
Penicillium
and
Aspergillus
genera were assembled. The WGS will allow for detailed genomic characterization to determine the possible applications and importance for space and biotechnological industries.
Supplemental Material: Water transfer to the deep mantle through hydrous, Al-rich silicates in subduction zones
Authors: Hermann Joerg , Lakey Shayne
Published: March 2021

Experimental and analytical methods, starting material, and characterization of experimental run products.
Supplemental Material: Paleozoic evolution of crustal thickness and elevation in the northern Appalachian orogen, USA
Authors: Hillenbrand Ian , Williams Michael
Published: March 2021

Geochemical and isotopic data, detailed descriptions of methods, and Figures S1–S4.
Supplemental Material: Progradational slope architecture and sediment distribution in outcrops of the mixed carbonate-siliciclastic Bone Spring Formation, Permian Basin, west Texas
Authors: Walker W. , al. et
Published: March 2021

Figure S1: Location of six photopanels compiled along the outcrop overlaying the 3D textured model. Figure S2: West-facing outcrop between Shumard Canyon and Bone Canyon. Characteristics of slope detachment surfaces aid in correlating surfaces from Shumard to Bone Canyons. Note the discontinuous nature of the terrigenous sediment within Clinothem 4 from Shumard to Bone Canyons (also shown in Fig. 3B). Figure S3: Location of detailed outcrop photos shown in this publication.
Towards universal health coverage in the WHO African Region: assessing health system functionality, incorporating lessons from COVID-19
Authors: Karamagi Humphrey Cyprian , Tumusiime Prosper , Titi-Ofei Regina , Droti Benson , Kipruto Hillary , Nabyonga-Orem Juliet , Seydi Aminata Binetou-Wahebine , Zawaira Felicitas , Schmets Gerard , Cabore Joseph Waogodo
Published: March 2021

The move towards universal health coverage is premised on having well-functioning health systems, which can assure provision of the essential health and related services people need. Efforts to define ways to assess functionality of health systems have however varied, with many not translating into concrete policy action and influence on system development. We present an approach to provide countries with information on the functionality of their systems in a manner that will facilitate movement towards universal health coverage. We conceptualise functionality of a health system as being a construct of four capacities: access to, quality of, demand for essential services and its resilience to external shocks. We test and confirm the validity of these capacities as appropriate measures of system functionality. We thus provide results for functionality of the 47 countries of the WHO African Region based on this. The functionality of health systems ranges from 34.4 to 75.8 on a 0–100 scale. Access to essential services represents the lowest capacity in most countries of the region, specifically due to poor physical access to services. Funding levels from public and out-of-pocket sources represent the strongest predictors of system functionality, compared with other sources. By focusing on the assessment on the capacities that define system functionality, each country has concrete information on where it needs to focus, in order to improve the functionality of its health system to enable it respond to current needs including achieving universal health coverage, while responding to shocks from challenges such as the 2019 coronavirus disease. This systematic and replicable approach for assessing health system functionality can provide the guidance needed for investing in country health systems to attain universal health coverage goals.
Changes in children’s surgical services during the COVID-19 pandemic at a tertiary-level government hospital in a lower middle-income country
Authors: Farooq Md. Abdullah Al , Kabir S M Humayun , Chowdhury Tanvir Kabir , Sadia Ayesha , Alam Md. Afruzul , Farhad Tanzil
Published: March 2021

Objective

The aim of this study was to quantify the changes that occurred in the surgical services of children during the COVID-19 pandemic from the perspective of a low/middle-income country.

Design

A case–control study was conducted at a large referral centre in Bangladesh among patients aged ≤12 years. Comparisons were made between cases admitted during a period of ‘April to September 2020’ (Pandemic period) and controls during a similar period in 2019 (Reference period). The number of admissions and outpatient department (OPD) attendances, age and sex distribution, diagnosis, number and types of surgeries performed (elective vs emergency), variations in treatment of acute appendicitis, types of anaesthesia and mortality were compared.

Results

Admissions were only 41% of previous year (635 vs 1549), and OPD attendances were only 28% of previous year (603 vs 2152). Admission of children reduced by 65.8%, but neonatal admission reduced only by 7.6%. The median age of the admitted patients was significantly lower during the pandemic period (3 vs 4 years, p<0.01). Acute appendicitis (151, 9.8%) and trauma (61, 9.6%), respectively, were the the most common causes of admission during the reference and the pandemic period. Elective surgeries were only 17% and emergency surgeries were 64% of previous year (p<0.01). Appendectomy (88, 9.1%) and laparotomy (77, 17.6%), respectively, were the most common surgeries performed during the reference and the pandemic period. Conservative treatment of acute appendicitis was more during the pandemic period (47.5% vs 28.5%, p=0.01), but patients who underwent appendectomies had more complicated appendicitis (63.3% vs 42.1%, p=0.01). In all, 90.4% of surgeries were performed by resident doctors. There were no COVID-19- related deaths.

Conclusion

Trauma became the most common cause of admission during the pandemic, and neonatal surgical conditions remained almost unchanged with high mortality rates. Elective procedures and laparoscopy remained low and resident doctors played a major role in providing surgical services.
Moving towards a local testing solution for undetermined thyroid fine-needle aspirates: validation of a novel custom DNA-based NGS panel
Authors: Sgariglia Roberta , Nacchio Mariantonia , Migliatico Ilaria , Vigliar Elena , Malapelle Umberto , Pisapia Pasquale , De Luca Caterina , Iaccarino Antonino , Salvatore Domenico , Masone Stefania , Troncone Giancarlo , Bellevicine Claudio
Published: March 2021

Aims

In thyroid cytopathology, the undetermined diagnostic categories still pose diagnostic challenges. Although next-generation sequencing (NGS) is a promising technique for the molecular testing of thyroid fine-needle aspiration (FNA) specimens, access to such technology can be difficult because of its prohibitive cost and lack of reimbursement in countries with universal health coverage. To overcome these issues, we developed and validated a novel custom NGS panel,Nexthyro,specifically designed to target 264 clinically relevant mutations involved in thyroid tumourigenesis. Moreover, in this study, we compared its analytical performance with that of our previous molecular testing strategy.

Methods

The panel, which includes 15 genes (BRAF, EIF1AX, GNAS, HRAS, IDH1, KRAS, NF2, NRAS, PIK3CA, PPM1D, PTEN, RET, DICER1, CHEK2, TERT promoter),was validated with a cell-line derived reference standard and 72 FNA archival samples previously tested with the 7-gene test.

Results

Nexthyroyielded 100% specificity and detected mutant alleles at levels as low as 2%. Moreover, in 5/72 (7%) FNAs, it detected more clinically relevant mutations inBRAFandRASgenes compared with the 7-gene test.Nexthyroalso revealed better postsequencing metrics than the previously adopted commercial ‘generic’ NGS panel.

Conclusion

Our comparative analysis indicates thatNexthyrois a reliable NGS panel. The study also implies that a custom-based solution for routine thyroid FNA is sustainable at the local level, allowing patients with undetermined thyroid nodules affordable access to NGS.
The Impact of Traumatic Brain Injury on Neurocognitive Outcomes in Children: a Systematic Review and Meta-Analysis
Authors: Goh Mark Sen Liang , Looi Dawn Shu Hui , Goh Jia Ling , Sultana Rehena , Goh Sharon Si Min , Lee Jan Hau , Chong Shu-Ling
Published: March 2021

Objective

To assess the burden of paediatric traumatic brain injury (TBI) on neurocognition via a systematic review and meta-analysis.

Methods

Studies that compared neurocognitive outcomes of paediatric patients with TBI and controls were searched using Medline, Embase, PsycINFO and Cochrane Central Register of Controlled Trials, between January 1988 and August 2019. We presented a random-effects model, stratified by TBI severity, time of assessment post injury and age.

Results

Of 5919 studies, 41 (patients=3717) and 33 (patients=3118) studies were included for the systematic review and meta-analysis, respectively. Studies mostly measured mild TBI (n=26, patients=2888) at 0–3 months postinjury (n=17, patients=2502). At 0–3 months postinjury, standardised mean differences between TBI and controls for executive function were −0.04 (95% CI −0.14 to 0.07; I2=0.00%), −0.18 (95% CI −0.29 to –0.06; I2=26.1%) and −0.95 (95% CI −1.12 to –0.77; I2=10.1%) for mild, moderate and severe TBI, respectively; a similar effect was demonstrated for learning and memory. Severe TBI had the worst outcomes across all domains and persisted >24 months postinjury. Commonly used domains differed largely from workgroup recommendations. Risk of bias was acceptable for all included studies.

Conclusion

A dose-dependent relationship between TBI severity and neurocognitive outcomes was evident in executive function and in learning and memory. Cognitive deficits were present for TBIs of all severity but persisted among children with severe TBI. The heterogeneity of neurocognitive scales makes direct comparison between studies difficult. Future research into lesser explored domains and a more detailed assessment of neurocognitive deficits in young children are required to better understand the true burden of paediatric TBI.
Occupations and exposure events in acute and subacute irritant-induced asthma
Authors: Lindström Irmeli , Lantto Jussi , Karvala Kirsi , Soini Satu , Ylinen Katriina , Suojalehto Hille , Suuronen Katri
Published: March 2021

Background

Exposures leading to irritant-induced asthma (IIA) are poorly documented.

Methods

We retrospectively screened the medical records of patients with IIA diagnosed in an occupational medicine clinic during 2000–2018. We classified the cases into acute (onset after single exposure) and subacute (onset after multiple exposures) IIA. We analysed in detail, occupations, causative agents and their air levels in the workplace, exposure events and the root causes of high exposure.

Results

Altogether 69 patients were diagnosed with IIA, 30 with acute and 39 with subacute IIA. The most common occupational groups were industrial operators (n=23, 33%), metal and machinery workers (n=16, 11%) and construction workers (n=12, 8%). Among industrial operators significantly more cases had subacute IIA than acute IIA (p=0.002). Forty cases (57%) were attributable to some type of corrosive acidic or alkaline chemical. Acute IIA followed accidents at work in different types of occupation, while subacute IIA was typical among industrial operators performing their normal work tasks under poor work hygiene conditions. The most common root cause was lack of information or false guidance in acute IIA (n=11, 36%) and neglect of workplace hygiene measures in subacute IIA (n=29, 74%).

Conclusions

Accidents are the main causes of acute IIA, whereas subacute IIA can develop in normal work in risk trades with poor work hygiene. Airborne strong acids or bases seem to be the most important causative agents of acute and subacute IIA. The different risk profiles of acute and subacute IIA should be considered in the prevention and identification of the cases.
Cross-sectional analysis of hospital tasks handed over to general practitioners: workload delegation or dumping?
Authors: Mughal Zahir , Maharjan Rajib
Published: March 2021

Purpose of the study

New requirements for hospital clinicians to follow up and act on hospital-initiated investigations were introduced in 2016 in the National Health Service standard contract. We aimed to evaluate the tasks handed over from hospital clinicians to general practitioners (GPs).

Study design

A retrospective observation of all tasks in a random sample of electronic discharge summaries at a university teaching hospital over a 1 month period was conducted. A single-best-answer questionnaire was circulated among hospital clinicians over 3 months to gain an understanding of their follow-up and referral practices.

Results

The total number of tasks found on discharge summaries (n=178) were 227, of which 39% were directed at GPs and 61% at the hospital team. Of 89 tasks delegated to GPs, 33% were inappropriate. Some tasks on discharge summaries were delegated more frequently to GPs such as blood tests (73%) and endoscopy requests (67%). While others were undertaken more often by hospitals clinicians including imaging requests (88%), follow-up appointments (87%) and onward referrals (71%). Surveyed doctors (n=72) admitted to asking GPs to follow up blood tests (52%), imaging and endoscopy (16%) and make onward referrals for related conditions (14%) and unrelated conditions (70%).

Conclusion

The majority of outstanding tasks in the hospital setting were followed up by hospital clinicians. A considerable volume of tasks were delegated to GPs, of which a significant proportion were inappropriate. An increase in awareness and understanding among hospital clinicians of their responsibility to follow up hospital-initiated investigations is needed.
Epidemiology and prognostic factors of pleural empyema
Authors: Bobbio Antonio , Bouam Samir , Frenkiel Jerome , Zarca Kevin , Fournel Ludovic , Canny Emelyne , Icard Philippe , Porcher Raphaël , Alifano Marco
Published: March 2021

Background

Infection of the pleural cavity invariably leads to hospitalisation, and a fatal outcome is not uncommon. Our aim was to study the epidemiology of pleural empyema on a nationwide basis in the whole population and in three subgroups of patients, namely post-lung resection, associated cancer and those with no surgery and no cancer.

Methods

Data from patients aged ≥18 years hospitalised with a diagnosis of pleural infection in France between January 2013 and December 2017 were retrieved from the medical-administrative national hospitalisation database and retrospectively analysed. Mortality, length of stay and costs were assessed.

Results

There were 25 512 hospitalisations for pleural empyema. The annual rate was 7.15 cases per 100 000 habitants in 2013 and increased to 7.75 cases per 100 000 inhabitants in 2017. The mean age of patients was 62.4±15.6 years and 71.7% were men. Post-lung resection, associated cancer and no surgery–no cancer cases accounted for 9.8%, 30.1% and 60.1% of patients, respectively. These groups were significantly different in terms of clinical characteristics, mortality and risk factors for length of stay, costs and mortality. Mortality was 17.1% in the whole population, 29.5% in the associated cancer group, 17.7% in the post-lung resection group and 10.7% in the no surgery–no cancer group. In the whole population, age, presence of fistula, higher Charlson Comorbidity Index (>3), alcohol abuse, arterial hypertension, hyperlipidaemia, atheroma, atrial fibrillation, performance status >3 and three subgroups of pleural empyema independently predicted mortality.

Conclusions

Empyema is increasing in incidence. Factors associated with mortality are recent lung resection and associated diagnosis of cancer.
A temperature measurement system with high resolution and low noise
Authors: Zhang Bing , Zhu Xiaoyi , Zhang Xiaofeng , Xue Bing , Liang Hong , Li Jiang , Su Peng ,   On behalf of The Taiji Scientific Collaboration
Published: March 2021

Due to the temperature fluctuation, both the self-gravity disturbance level of the gravitational wave detection vehicle and the laser interference measurement system are affected, which brings great noise to the gravitational wave measurement, and the temperature field fluctuation has become one of the most important noise sources of the inertial sensor. In order to ensure the noise level of the inertial sensor to meet the needs of detection, this paper uses the AC bridge to reduce the self-noise of the temperature measurement system, improve the resolution of the temperature measurement system, and realize a high-resolution and low-noise temperature measurement system. The experimental results show that the effective value of self-noise of the temperature measurement system is about 3.65 × 10[Formula: see text], and the long-period noise is less than 1 × 10[Formula: see text]. It can be used in the space gravitational wave detection test and control system.
Simulation of metal microcomponents picking up by electrochemical based on ABAQUS
Authors: Li Dongjie , Wang Mingrui , Xu Jiyong , Yang Liu , Zhang Yu
Published: March 2021

The development of micromanipulation technology has an important impact on the research in the microfield, which mainly focuses on the preparation and assembly of microcomponents, in which the microcomponent picking technology is used. The existing picking methods mainly use manipulation tools to clamp or adsorb components, which may destroy or fail to pick objects in the process of manipulation, and the efficiency is relatively low. In order to solve the problems in the existing manipulation methods, a new metal microcomponent picking method based on electrochemistry is proposed, which mainly uses the electrochemical principle to produce metal deposition, connect the manipulation tool and the object, and indirectly control the object by moving the manipulation tool. In this paper, the simulation software ABAQUS is used to pick up the microcopper wires with the length of 100, 200 and 300 [Formula: see text]m by using a pipette with a nozzle diameter of 15 [Formula: see text]m. The force curve between the tool and the object during the manipulation process is obtained. The feasibility of the method is verified by theoretical analysis and simulation experiments.
An integrable soliton hierarchy associated with the Boiti–Pempinelli–Tu spectral problem
Authors: Appiah Emmanuel A. , Manukure Solomon
Published: March 2021

Based on the Tu scheme [G.-Z. Tu, J. Math. Phys. 30 (1989) 330], we construct a counterpart of the Boiti–Pempinelli–Tu soliton hierarchy from a matrix spectral problem associated with the Lie algebra [Formula: see text], and formulate Hamiltonian structures for the resulting soliton equations by means of the trace identity. We then show that the newly presented equations possess infinitely many commuting symmetries and conservation laws. Finally, we derive the well-known combined KdV-mKdV equation from the new hierarchy.
On the stability of pressure isotropy condition in Palatini f(R) gravity
Authors: Tariq Z. , Bhatti M. Z. , Yousaf Z.
Published: March 2021

This paper copes with the issue of analyzing the conditions to check the stability of the pressure isotropy condition by taking into account a spherically symmetric dissipative astrophysical configuration with the Palatini [Formula: see text] gravity theory. We work out a differential equation in terms of the Weyl scalar that has a crucial part in the analysis of evolution of considered system. Using this equation, we devise another stellar equation that characterizes the evolution of anisotropic factor. Later, we assume an axially symmetric configuration and extend our analysis for that particular symmetry. It is worth-observing that the physical factors responsible for compelling an initially isotropic object to trigger pressure anisotropy incorporate energy density, dissipative flux and shear in fluid flow.
CORROSION STUDY OF ZINC-RICH EPOXY ESTER PAINTS FOR COLD GALVANIZING OF MILD STEEL
Authors: MAQSOOD MUHAMMAD FAHEEM , RAZA MOHSIN ALI , REHMAN ZAEEM UR , ABID MUHAMMAD , INAM AQIL , IQBAL SHAHID
Published: March 2021

This study aims at producing zinc (Zn)-rich epoxy ester (EE) paints for cold galvanizing of mild steel. Zn particles with a narrow particle size distribution of 1[Formula: see text][Formula: see text]m to 5[Formula: see text][Formula: see text]m were dispersed in EE resin by vacuum centrifuge mixer. The effect of Zn concentration in EE resin on cathodic protection ability of resulting paints was studied. Galvanic corrosion protection ability of the paints was studied in 3.5% (mass ratio) NaCl solution using electrochemical characterization techniques such as open circuit potential (OCP), Tafel analysis and electrochemical impedance spectroscopy (EIS). The results showed that cathodic protection ability depends on the loading of Zn particles in the EE and it is effective when the mass fraction of Zn was equal to or exceeded 90%. At this concentration, Zn particles developed interconnecting conducting networks as determined by scanning electron microscopy (SEM) which were responsible for the galvanic effect of the coating. The EE paints developed at mass ratio below 90% behaved as a conventional organic barrier coating and did not show any cathodic protection effect due to the lack of contact between Zn particles. The EE paint showed good resistance to abrasion and wear. The electrochemical behavior of Zn-rich EE paint (with cathodic protection ability) developed in this study was compared with commercial acrylic-based “cold galvanized paint” (Roval). EE-based “cold galvanized paints” were found to be more protective and long lasting compared to commercial “cold galvanized paints”.
INVESTIGATION OF DRY SLIDING WEAR BEHAVIOR OF AL 7075–(SiC/TiC) HYBRID METAL MATRIX COMPOSITES
Authors: GUKENDRAN R. , SAMBATHKUMAR M. , SASIKUMAR K. S. K. , PONAPPA K. , GOPAL S.
Published: March 2021

The main objective of present work focuses to investigate the tribological behavior of Al 7075 hybrid metal matrix composite. Al 7075 metal matrix composites has many potential applications especially in automotive and aerospace industries, due to their light weight to strength ratio and high wear resistance. The composite is fabricated using two step stir casting process by varying 5% to 15% volume fractions of Silicon Carbide and Titanium Carbide. Optical microstructure showed reinforcement distribution into Al 7075 matrix. The wear and frictional properties of the hybrid metal matrix composites was studied by performing dry sliding wear test using a pin-on-disc wear tester. Tribological behaviors were examined by applying different normal loads of 10[Formula: see text]N, 20[Formula: see text]N, 30[Formula: see text]N with different sliding velocities (1[Formula: see text]m/s, 2[Formula: see text]m/s, 3[Formula: see text]m/s) at room temperature without lubrication. Wear rate and coefficient of friction for different normal load and sliding velocities were plotted and studied. The micro hardness value of AST15 was higher by 18.8% than the AST0 Composites. The wear rate prediction indicated the wear rate for AST15 as [Formula: see text][Formula: see text]mm3/m as compared to AST0 which was [Formula: see text][Formula: see text]mm3/m. The wear rate increases with the increase in load and sliding velocities. Scanning electron microscopy micrographs of the worn surface are used to predict the nature of the wear mechanism.
On canonical bases of a formal 𝕂-algebra
Authors: Assi Abdallah
Published: March 2021

We study canonical bases of a subalgebra [Formula: see text] over a field [Formula: see text], and we associate with [Formula: see text] a fan called the canonical fan of [Formula: see text]. This generalizes the notion of the standard fan of an ideal.
Asymptotic dimension and coarse embeddings in the quantum setting
Authors: Chávez-Domínguez Javier Alejandro , Swift Andrew T.
Published: March 2021

We generalize the notions of asymptotic dimension and coarse embeddings from metric spaces to quantum metric spaces in the sense of Kuperberg and Weaver [A von Neumann algebra approach to quantum metrics, Mem. Am. Math. Soc. 215(1010) (2012) 1–80]. We show that quantum asymptotic dimension behaves well with respect to metric quotients and direct sums, and is preserved under quantum coarse embeddings. Moreover, we prove that a quantum metric space that equi-coarsely contains a sequence of expanders must have infinite asymptotic dimension. This is done by proving a quantum version of a vertex-isoperimetric inequality for expanders, based upon a previously known edge-isoperimetric one from [K. Temme, M. J. Kastoryano, M. B. Ruskai, M. M. Wolf and F. Verstraete, The [Formula: see text]-divergence and mixing times of quantum Markov processes, J. Math. Phys. 51(12) (2010) 122201].
Hit problem for the polynomial algebra as a module over the Steenrod algebra in some degrees
Authors: Tín Nguyễn Khắc
Published: March 2021

Let [Formula: see text] be the polynomial algebra in [Formula: see text] variables with the degree of each [Formula: see text] being [Formula: see text] regarded as a module over the mod-[Formula: see text] Steenrod algebra [Formula: see text] and let [Formula: see text] be the general linear group over the prime field [Formula: see text] which acts naturally on [Formula: see text]. We study the hit problem, set up by Frank Peterson, of finding a minimal set of generators for the polynomial algebra [Formula: see text] as a module over the mod-2 Steenrod algebra, [Formula: see text]. These results are used to study the Singer algebraic transfer which is a homomorphism from the homology of the mod-[Formula: see text] Steenrod algebra, [Formula: see text] to the subspace of [Formula: see text] consisting of all the [Formula: see text]-invariant classes of degree [Formula: see text] In this paper, we explicitly compute the hit problem for [Formula: see text] and the degree [Formula: see text] with [Formula: see text] an arbitrary positive integer. Using this result, we show that Singer’s conjecture for the algebraic transfer is true in the case [Formula: see text] and the above degree.
Spatial Path Tracking Controllers for Autonomous Ground Vehicles: Conventional and Nonconventional Schemes
Authors: Wang Peng , An Di , Chen Ning , Chen Yang Quan
Published: March 2021

Unlike time-based path tracking controllers, the [Formula: see text]-controller is a spatial path tracking controller. It is a purely geometric path tracking controller and essentially a P-controller to maintain the reasonable spatial distance, [Formula: see text], from the vehicle to the desired path. In this paper, we present some enhancement schemes using the non-conventional PI control laws via optimization. We propose to use a nonlinear term [Formula: see text] for the proportional controller. A fractional-order integral used to achieve a PI[Formula: see text] control. Among the schemes, an optimization search procedure applied to find optimal controller gains by meshing the regions around the values from approximate linear designs. The performance index for parametric optimization is the integration of the absolute purely spatial deviation from the desired path. Three different types of road shape were chosen and the Gazebo-ROS simulation results were presented to show the effectiveness of the proposed enhancement schemes. The results show that in some cases a smaller [Formula: see text] and [Formula: see text] can be achieved by using [Formula: see text] controller, but its disadvantage is there may be some oscillation. For PI[Formula: see text] controller, there is an additional adjustable parameter [Formula: see text], better performance can be achieved without significant disadvantages which is worth in-depth research.
Socializing the web
Authors: Donath Judith
Published: March 2021

Though today we think of the web and social media as nearly synonymous, the technology of the early web made social interaction difficult. The author discusses her work creating some of the web's earliest social applications and asks why our interfaces for seeing and communicating with each other online are still so primitive.
The shape of our feminisms
Authors: Mustafa Maryam
Published: March 2021

Understanding agency and empowerment outside the Global North.
Study of the Electron Transfer in Titanium Containing Melts by Electrochemical and Quantum-Chemical Methods
Authors: Stulov Yu. V. , Vetrova D. A. , Kremenetsky V. G. , Kuznetsov S. A.
Published: March 2021

The electron transfer mechanism in a titanium containing system was investigated by electrochemical and quantum-chemical methods. The kinetics of charge transfer for the Ti(IV)/Ti(III) redox couple in the (NaCl–KCl)equimol–NaF (10 wt%)-K2TiF6 melt with addition of Ca2+ cations was studied by cyclic voltammetry. The standard rate constants of charge transfer (k

s
) were calculated by Nicholson’s method. The increase values of the k

s
reaching the maximum at mole ratio Ca2+/Ti(IV) equals 1:1 was found. Values of activation energy for system with Ca2+ cations are considerably less than activation energies of the system without Ca2+ cations. The quantum-chemical calculations were performed using the Firefly quantum-chemical package by methods of the density functional theory. Structures with a high probability of the electron transfer from the cathode to the titanium complex were found. Using the Frontier molecular orbital method made it possible with a small amount of computer time to determine the structure of the transition state of the TiF6
2− complex. The calculated activation energy of the electron transfer was in a good agreement with experimentally determined value.
Biomass-Derived Ternary-Doped Porous Carbon Electrodes for Li-Ion Capacitors: Rational Preparation and Energy-Storage Mechanism Study
Authors: Jiang Zepeng , Liu Mengyue , Zhu Feng , Song Weihao , Zhang Zhengping , Dou Meiling , Niu Jin , Wang Feng
Published: March 2021

Owing to the hybrid energy-storage features, Li-ion capacitors (LICs) inherit appealing properties from secondary batteries and supercapacitors, including high power density, high energy density and good cycling stability. However, incompatible kinetics between anode and cathode limit the performance improvement of the LICs. Moreover, the energy-storage mechanisms of carbon electrodes for LICs need to be further explored. Herein, we have prepared two ginkgo leaf-derived porous carbons (GLPCs) and used them as LIC electrodes. As resourceful biomass materials, ginkgo leaves have numerous O,N,S-enriched organics (e.g., flavonoids, alkaloids and thiophenes). By direct pyrolysis of the ginkgo leaves, ternary doped GLPCs are obtained without using additional dopants. The porosities, heteroatoms and defects for the GLPCs are tailored based on electrode requirements. The GLPCs obtained at 600 and 900 °C are specifically employed as the anode and cathode materials for LICs, respectively. The GLPC electrodes show good performance in half cells and their energy-storage mechanisms are interpreted by detailed ex situ and in situ experiments. DFT calculation results reveal that only specific heteroatom doping can enhance Li+ and PF6
− storage. Because of compatible electrode kinetics, the assembled LIC using the GLPC electrodes delivers high energy (118 Wh kg−1), high power (31.6 kW kg−1) and long lifespan.
From the Editor: It Is Elemental, My Dear Watson!
Authors: Rajeshwar Krishnan
Published: March 2021

The science and technology world has seen some exciting events unfold during the past couple of months. Coupled with the Mars exploration, President Bush’s January 14 announcement of a new space program and the projected infusion of funds (in the $12 billion range over a five-year period), all portend a healthy future for America’s space program.
Pennington Corner: 2003…Best Year Ever?
Authors: Calvo Roque J.
Published: March 2021

In the world today, people are interested in having the best or the biggest or maybe the fastest “thing” ever. But how can you judge what is the best and who can really say when you have found it? So I don’t know if 2003 is really the best year ever for the Society, because it depends upon what criteria you choose to define the best.
From the President: One Stop Shopping
Authors: Susko Robin
Published: March 2021

With today’s fast paced life there seems to be vastly less time in a given day. At work there continues to be an increasing demand on a range of tasks one must accomplish in an expedited fashion with fewer people and limited resources. When talking to friends, they often suggest that they have so little time to do all the things they want to do. I believe as a result of the increased premium placed on a person’s time, there has been a culture change.
From the President: Movers and Shakers
Authors: Susko Robin
Published: March 2021

As ECS President, I recently had the privilege of representing the Society at the Perkin Medal award ceremony in Philadelphia. The event was particularly gratifying since the 2004 recipient of this prestigious award was Dr. Gordon E. Moore. Dr. Moore co-founded both Fairchild Semiconductor and Intel.
Free Radicals: A Weekend Trip to Mars
Authors: Greatbatch Wilson
Published: March 2021

By the year 2050 AD, we will have run out of all the economically recoverable fossil fuels. Our natural gas will be exhausted. Our oil will be exhausted. We will still have about 100 years supply of coal left if we are willing to put up with the “greenhouse gases” that result from using it.
The Chalkboard: The Glass pH Electrode
Authors: Vanysek Petr
Published: March 2021

We are pleased to introduce a new magazine column, The Chalkboard, that aims to take the reader back to the classroom. This series of tutorials will be written by experts for a non-specialist audience.
Electrochemistry and the Hydrogen Economy
Authors: Turner John A.
Published: March 2021

Hydrogen is a hot topic in our society today. Issues relating to hydrogen run the gauntlet from energy, economics, and the environment to foreign and domestic policy. The vision of the widespread production, storage, distribution, and use of hydrogen as an energy carrier is often termed, “the hydrogen economy.” This vision can offer energy security for the nation, provide enormous environmental benefits for our cities and towns, and increase the reliability, “dispatchability,” and quality of our electric power system.
Electrodeposition: A Bright (But Perhaps Not Chrome-Plated) Future
Authors: Stickney John
Published: March 2021

Here is the good news, folks! Electrodeposition is not just for breakfast anymore. No, no, no! We are coming out of the dark ages, into the light! Someone loves us and it is not our mothers! What am I talking about? To me, traditional electrodeposition harks back to images of a hunchback in a dark warehouse, stooped over boiling vats of cyanide and acid, bringing the world the largest selection of cheap jewelry, Harley Davidson parts, and car bumpers.
Electrodeposition of Nanostructured Films Using Self-Organizing Templates
Authors: Bartlett Philip N.
Published: March 2021

Over the last eight years, together with colleagues in Southampton, we have been interested in the templated electrodeposition of regularly structured nanoporous materials and their properties and applications. Over this time we have worked extensively with two different types of self-organizing template: lyotropic liquid crystalline phases and close-packed arrays of spherical colloidal polystyrene particles.
DNA Damage Inhibition by Dietary Antioxidants: Voltammetric Detection of Inhibition Using Metallopolymer Catalysts
Authors: Mugweru Amos
Published: March 2021

A Summary Report to The Electrochemical Society for the 2004 Colin Garfield Fink Summer Research Fellowship.
Sodium sensitivity of KNachannels in mouse CA1 neurons
Authors: Gray Richard , Johnston Daniel
Published: March 2021

We studied KNachannels in mouse hippocampal CA1 neurons. Excised inside-out patches showed the channels to be prevalent and active in most patches in the presence of Na+. Cell-attached recordings from intact neurons, however, showed little channel activity. Increasing cytoplasmic sodium in intact cells showed a small effect on channel activity compared with that seen in inside-out excised patches. Blockade of the Na+/K+pump with ouabain, however, restored the activity of the channels to that seen in inside-out patches.
Distributed processing of load and movement feedback in the premotor network controlling an insect leg joint
Authors: Gebehart Corinna , Schmidt Joachim , Büschges Ansgar
Published: March 2021

Proprioception is crucial for motor control in legged animals. We show the extent to which processing of movement (fCO) and load (CS) signals overlaps in the local premotor network of an insect leg. Multimodal signals converge onto the same set of interneurons, and our knowledge about distributed, antagonistic processing is extended to incorporate multiple modalities within one perceptual neuronal framework.
Grip force anticipation of nonlinear, underactuated load force
Authors: Grover Francis M. , Riehm Christopher , Silva Paula L. , Lorenz Tamara , Riley Michael A.
Published: March 2021

From the perspective of feedforward internal model-based control, precise, anticipatory grip force (GF) control when manipulating a complex object should not be possible as the object’s changing load forces (LFs) cannot be encoded by efference copies of the underlying movements. However, we observed that GF exhibited strong, precise, anticipatory coupling with LF during extended manipulations of a complex object. These findings suggest that an alternative theoretical framework is needed to account for anticipatory GF control.