bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between cardiometabolic disease and severe COVID-19: a nationwide case–control study of patients requiring invasive mechanical ventilation
Authors: Svensson Per , Hofmann Robin , Häbel Henrike , Jernberg Tomas , Nordberg Per
Published: February 2021

Aims

The risks associated with diabetes, obesity and hypertension for severe COVID-19 may be confounded and differ by sociodemographic background. We assessed the risks associated with cardiometabolic factors for severe COVID-19 when accounting for socioeconomic factors and in subgroups by age, sex and region of birth.

Methods and results

In this nationwide case–control study, 1.086 patients admitted to intensive care with COVID-19 requiring mechanical ventilation (cases), and 10.860 population-based controls matched for age, sex and district of residency were included from mandatory national registries. ORs with 95% CIs for associations between severe COVID-19 and exposures with adjustment for confounders were estimated using logistic regression. The median age was 62 years (IQR 52–70), and 3003 (24.9%) were women. Type 2 diabetes (OR, 2.3 (95% CI 1.9 to 2.7)), hypertension (OR, 1.7 (95% CI 1.5 to 2.0)), obesity (OR, 3.1 (95% CI 2.4 to 4.0)) and chronic kidney disease (OR, 2.5 (95% CI 1.7 to 3.7)) were all associated with severe COVID-19. In the younger subgroup (below 57 years), ORs were significantly higher for all cardiometabolic risk factors. The risk associated with type 2 diabetes was higher in women (p=0.001) and in patients with a region of birth outside European Union(EU) (p=0.004).

Conclusion

Diabetes, obesity and hypertension were all independently associated with severe COVID-19 with stronger associations in the younger population. Type 2 diabetes implied a greater risk among women and in non-EU immigrants. These findings, originating from high-quality Swedish registries, may be important to direct preventive measures such as vaccination to susceptible patient groups.

Trial registration number

Clinicaltrial.gov (NCT04426084).
Incidence, duration and risk factors associated with delayed and missed diagnostic opportunities related to tuberculosis: a population-based longitudinal study
Authors: Miller Aaron C , Arakkal Alan T , Koeneman Scott , Cavanaugh Joeseph E , Gerke Alicia K , Hornick Douglas B , Polgreen Philip M
Published: February 2021

Objectives

Missed opportunities to diagnose tuberculosis are costly to patients and society. In this study, we (1) estimate the frequency and duration of diagnostic delays among patients with active pulmonary tuberculosis and (2) determine the risk factors for experiencing a diagnostic delay.

Design

A retrospective cohort study of patients with tuberculosis using longitudinal healthcare encounters prior to diagnosis.

Setting

Commercially insured enrollees from the Commercial Claims and Encounters or Medicare Supplemental IBM Marketscan Research Databases, 2001–2017.

Participants

All patients diagnosed with, and receiving treatment for, pulmonary tuberculosis, enrolled at least 365 days prior to diagnosis.

Primary and secondary outcome measures

We estimated the number of visits with tuberculosis-related symptoms prior to diagnosis that would be expected to occur in the absence of delays and compared this estimate to the observed pattern. We computed the number of visits representing a delay and used a simulation-based approach to estimate the number of patients experiencing a delay, number of missed opportunities per patient and duration of delays (ie, time between diagnosis and earliest missed opportunity). We also explored risk factors for missed opportunities.

Results

We identified 3371 patients diagnosed and treated for active tuberculosis that could be followed up for 1 year prior to diagnosis. We estimated 77.2% (95% CI 75.6% to 78.7%) of patients experienced at least one missed opportunity; of these patients, an average of 3.89 (95% CI 3.65 to 4.14) visits represented a missed opportunity, and the mean duration of delay was 31.66 days (95% CI 28.51 to 35.11). Risk factors for delays included outpatient or emergency department settings, weekend visits, patient age, influenza season presentation, history of chronic respiratory symptoms and prior fluoroquinolone use.

Conclusions

Many patients with tuberculosis experience multiple missed diagnostic opportunities prior to diagnosis. Missed opportunities occur most commonly in outpatient settings and numerous patient-specific, environment-specific and setting-specific factors increase risk for delays.
Risk of COVID-19 hospital admission and COVID-19 mortality during the first COVID-19 wave with a special emphasis on ethnic minorities: an observational study of a single, deprived, multiethnic UK health economy
Authors: Singh Baldev M , Bateman James , Viswanath Ananth , Klaire Vijay , Mahmud Sultan , Nevill Alan , Dunmore Simon J
Published: February 2021

Objectives

The objective of this study was to describe variations in COVID-19 outcomes in relation to local risks within a well-defined but diverse single-city area.

Design

Observational study of COVID-19 outcomes using quality-assured integrated data from a single UK hospital contextualised to its feeder population and associated factors (comorbidities, ethnicity, age, deprivation).

Setting/participants

Single-city hospital with a feeder population of 228 632 adults in Wolverhampton.

Main outcome measures

Hospital admissions (defined as COVID-19 admissions (CA) or non-COVID-19 admissions (NCA)) and mortality (defined as COVID-19 deaths or non-COVID-19 deaths).

Results

Of the 5558 patients admitted, 686 died (556 in hospital); 930 were CA, of which 270 were hospital COVID-19 deaths, 47 non-COVID-19 deaths and 36 deaths after discharge; of the 4628 NCA, there were 239 in-hospital deaths (2 COVID-19) and 94 deaths after discharge. Of the 223 074 adults not admitted, 407 died. Age, gender, multimorbidity and black ethnicity (OR 2.1 (95% CI 1.5 to 3.2), p<0.001, compared with white ethnicity, absolute excess risk of <1/1000) were associated with CA and mortality. The South Asian cohort had lower CA and NCA, lower mortality compared with the white group (CA, 0.5 (0.3 to 0.8), p<0.01; NCA, 0.4 (0.3 to 0.6), p<0.001) and community deaths (0.5 (0.3 to 0.7), p<0.001). Despite many common risk factors for CA and NCA, ethnic groups had different admission rates and within-group differing association of risk factors. Deprivation impacted only the white ethnicity, in the oldest age bracket and in a lesser (not most) deprived quintile.

Conclusions

Wolverhampton’s results, reflecting high ethnic diversity and deprivation, are similar to other studies of black ethnicity, age and comorbidity risk in COVID-19 but strikingly different in South Asians and for deprivation. Sequentially considering population and then hospital-based NCA and CA outcomes, we present a complete single health economy picture. Risk factors may differ within ethnic groups; our data may be more representative of communities with high Black, Asian and minority ethnic populations, highlighting the need for locally focused public health strategies. We emphasise the need for a more comprehensible and nuanced conveyance of risk.
Virtual reality in specialist palliative care: a feasibility study to enable clinical practice adoption
Authors: Nwosu Amara Callistus , Mills Mark , Roughneen Simon , Stanley Sarah , Chapman Laura , Mason Stephen R
Published: February 2021

Background

The use of virtual reality (VR) is increasing in palliative care. However, despite increasing interest in VR, there is little evidence of how this technology can be implemented into practice.

Aims

This paper aims to: (1) explore the feasibility of implementing VR therapy, for patients and caregivers, in a hospital specialist inpatient palliative care unit and a hospice, and (2) to identify questions for organisations, to support VR adoption in palliative care.

Methods

The Samsung Gear VR system was used in a hospital specialist palliative inpatient unit and a hospice. Patients and caregivers received VR distraction therapy and provided feedback of their experience. Staff completed a feedback questionnaire to explore their opinion of the usefulness of VR in palliative care. A public engagement event was conducted, to identify questions to support implementation of VR in palliative care settings.

Results

Fifteen individuals (12 (80%) patients and 3 (20%) caregivers) participated. All had a positive experience. No adverse effects were reported. Ten items were identified for organisations to consider ahead of adoption of VR in palliative care. These were questions about: the purpose of VR; intended population; supporting evidence; session duration; equipment choice; infection control issues; content choice; setting of VR; person(s) responsible for delivery and the maintenance plan.

Conclusions

It is feasible to use VR therapy in palliative care; however, further evidence about its efficacy and effectiveness is needed. Palliative care practitioners considering VR use should carefully consider several factors, to ensure that this technology can be used safely and effectively in clinical practice.
DNA mismatch repair proteins: scientific update and practical guide
Authors: Bateman Adrian C
Published: February 2021

DNA mismatch repair (MMR) proteins are essential for the recognition and correction of sporadic genetic mutations that occur during DNA replication. Deficient MMR function (dMMR) leads to an increased risk of development of neoplasia. Identification of dMMR within tumours can suggest a high chance of the inherited cancer condition Lynch syndrome and predicts poor clinical response to certain conventional chemotherapies but an increased likelihood of response to immunotherapy. This review provides an update on the biology of MMR proteins, their encoding genes and mechanisms for the development of dMMR. This is followed by a discussion of the identification and significance of dMMR in routine clinical practice.
Money is not everything: experimental evidence that payments do not increase willingness to be vaccinated against COVID-19
Authors: Sprengholz Philipp , Eitze Sarah , Felgendreff Lisa , Korn Lars , Betsch Cornelia
Published: February 2021

Rapid, large-scale uptake of new vaccines against COVID-19 will be crucial to decrease infections and end the pandemic. In a recent article in this journal, Julian Savulescu argued in favour of monetary incentives to convince more people to be vaccinated once the vaccine becomes available. To evaluate the potential of his suggestion, we conducted an experiment investigating the impact of payments and the communication of individual and prosocial benefits of high vaccination rates on vaccination intentions. Our results revealed that none of these interventions or their combinations increased willingness to be vaccinated shortly after a vaccine becomes available. Consequently, decision makers should be cautious about introducing monetary incentives and instead focus on interventions that increase confidence in vaccine safety first, as this has shown to be an especially important factor regarding the demand for the new COVID-19 vaccines.
Risk for infections with glucocorticoids and DMARDs in patients with rheumatoid arthritis
Authors: Riley Thomas R , George Michael D
Published: February 2021

Immunomodulatory therapy for rheumatoid arthritis (RA) carries risk for infectious complications. Understanding the risks of different therapeutic options is essential for making treatment decisions and appropriately monitoring patients. This review examines data on the risks for serious infections and other key infections of interest for the major classes of agents in use for RA: glucocorticoids, conventional synthetic disease-modifying antirheumatic drugs (DMARDs), biologics and Janus kinase (JAK) inhibitors. Conventional synthetic DMARDs have an excellent safety profile with recent data available supporting the relative safety of methotrexate. Tumour necrosis factor (TNF) inhibitors are associated with an increase in the risk of serious infections. Risk with other biological agents and with JAK inhibitors varies somewhat but overall appears similar to that of TNF inhibitors, with JAK inhibitors also associated with a greater risk of herpes zoster. Glucocorticoids have a dose-dependent effect on serious infection risk—at higher doses risk of infection with glucocorticoids is substantially greater than with other immunomodulatory therapies, and even low-dose therapy carries a risk of infection that appears to be similar to that of biological therapies.
Adverse pregnancy and neonatal outcomes associated with
Neisseria gonorrhoeae:
systematic review and meta-analysis
Authors: Vallely Lisa M , Egli-Gany Dianne , Wand Handan , Pomat William S , Homer Caroline S E , Guy Rebecca , Silver Bronwyn , Rumbold Alice R , Kaldor John M , Vallely Andrew J , Low Nicola
Published: February 2021

Objective

To examine associations between
Neisseria gonorrhoeae
(NG) infection during pregnancy and the risk of preterm birth, spontaneous abortion, premature rupture of membranes, perinatal mortality, low birth weight and ophthalmia neonatorum.

Data sources

We searched Medline, EMBASE, the Cochrane Library and Cumulative Index to Nursing and Allied Health Literature for studies published between 1948 and 14 January 2020.

Methods

Studies were included if they reported testing for NG during pregnancy and compared pregnancy, perinatal and/or neonatal outcomes between women with and without NG. Two reviewers independently assessed papers for inclusion and extracted data. Risk of bias was assessed using established checklists for each study design. Summary ORs with 95% CIs were generated using random effects models for both crude and, where available, adjusted associations.

Results

We identified 2593 records and included 30 in meta-analyses. Women with NG were more likely to experience preterm birth (OR 1.55, 95% CI 1.21 to 1.99, n=18 studies); premature rupture of membranes (OR 1.41, 95% CI 1.02 to 1.92, n=9); perinatal mortality (OR 2.16, 95% CI 1.35 to 3.46, n=9); low birth weight (OR 1.66, 95% CI 1.12 to 2.48, n=8) and ophthalmia neonatorum (OR 4.21, 95% CI 1.36 to 13.04, n=6). Summary adjusted ORs were, for preterm birth 1.90 (95% CI 1.14 to 3.19, n=5) and for low birth weight 1.48 (95% CI 0.79 to 2.77, n=4). In studies with a multivariable analysis, age was the variable most commonly adjusted for. NG was more strongly associated with preterm birth in low-income and middle-income countries (OR 2.21, 95% CI 1.40 to 3.48, n=7) than in high-income countries (OR 1.38, 95% CI 1.04 to 1.83, n=11).

Conclusions

NG is associated with a number of adverse pregnancy and newborn outcomes. Further research should be done to determine the role of NG in different perinatal mortality outcomes because interventions that reduce mortality will have the greatest impact on reducing the burden of disease in low-income and middle-income countries.

PROSPERO registration number

CRD42016050962.
Optical trapping and critical Casimir forces
Authors: Callegari Agnese , Magazzù Alessandro , Gambassi Andrea , Volpe Giovanni
Published: February 2021

Critical Casimir forces emerge between objects, such as colloidal particles, whenever their surfaces spatially confine the fluctuations of the order parameter of a critical liquid used as a solvent. These forces act at short but microscopically large distances between these objects, reaching often hundreds of nanometers. Keeping colloids at such distances is a major experimental challenge, which can be addressed by the means of optical tweezers. Here, we review how optical tweezers have been successfully used to quantitatively study critical Casimir forces acting on particles in suspensions. As we will see, the use of optical tweezers to experimentally study critical Casimir forces can play a crucial role in developing nano-technologies, representing an innovative way to realize self-assembled devices at the nano- and microscale.
WHAT IS AN “EFFECTIVE” ASEAN COMPETITION LAW? A METHODOLOGICAL NOTE
Authors: IAN MCEWIN ROBERT , CHOKESUWATTANASKUL PEERAPAT
Published: February 2021

ASEAN is currently reviewing its competition laws with “the difficult task of operationalizing the term effectiveness.” But the review seems more concerned with achieving international best practice rather than promoting effective economic outcomes that are based on local economic and institutional conditions and Asian business practices. There has been minimal input from ASEAN economists in the development and administration of ASEAN competition laws. Instead, ASEAN competition laws are mainly shaped and administered by lawyers who are more concerned with international comparisons of administrable laws, system administration and procedures and not so much with either local economic conditions or the ability of local competition regulators to achieve good economic outcomes. There is an extensive business school literature that shows that Asian business operates differently from those in the West. But these differences are not recognized in the design and operation of ASEAN competition laws.

This paper first, reviews how economics can contribute to both the design and implementation of effective ASEAN competition laws that take into account differences in business practices, economic conditions and institutional capacities. Second, because competition laws are mainly designed and run by lawyers, the paper also examines how lawyers perceive and research the transfer of legal rules from one country to another. This provides a guide to economists interested in research on the law and economics of competition law within ASEAN. The authors hope that it will stimulate both economists (and lawyers interested in economics) to undertake practical empirical research that will enhance the effectiveness of ASEAN competition laws and their possible convergence.
FINANCIAL AVAILABILITY, INCOME GAP AND HOUSEHOLD CONSUMPTION RATE IN TRANSITIONAL CHINA: A THEORETICAL APPROACH AND EMPIRICAL TEST
Authors: GUO NIANZHI , TSAO HAI-TAO , ZHAO DI
Published: February 2021

Based on the characteristics of financial exclusion and income gap, this paper attempted to elucidate the fluctuation of China’s consumption rate through the mechanism of financial availability of low-income residents and its influence on household consumption in the reform era. The study showed that improving financial availability affects the consumption rate by increasing investment opportunities for low-income earners who can adjust the portfolio of composition. Meanwhile, this effect is affected by the income gap which plays a “threshold” role in the relationship between financial availability and consumption rate. Therefore, inclusive finance development must be adapted to economic development in order to prevent “too much finance”.
Using molecular docking and molecular dynamics to investigate protein-ligand interactions
Authors: Morris Connor J. , Corte Dennis Della
Published: February 2021

Molecular docking and molecular dynamics (MD) are powerful tools used to investigate protein-ligand interactions. Molecular docking programs predict the binding pose and affinity of a protein-ligand complex, while MD can be used to incorporate flexibility into docking calculations and gain further information on the kinetics and stability of the protein-ligand bond. This review covers state-of-the-art methods of using molecular docking and MD to explore protein-ligand interactions, with emphasis on application to drug discovery. We also call for further research on combining common molecular docking and MD methods.
A general framework of high-resolution hybrid central/WENO numerical scheme for turbulent compressible simulation
Authors: Li Liang , Zhao Guo-Yan , Wang Hong-Bo , Sun Ming-Bo , Xiong Da-Peng , Tang Tao , Liu Ming-Jiang
Published: February 2021

This work presents a general framework of finite-difference hybrid scheme which contains a linear central scheme and a nonl-inear WENO scheme. A new optimal-designed shock sensor is used to distinguish the smoothness of flowfield and a binary-type weighting function is used to switch sub-schemes rationally. Based on the above improvements, the effects of different combinations of each component within the hybrid scheme are characterized in linear advection equation and Euler equations. The maximum reference threshold values are provided. Extensive test cases indicate the hybrid scheme’s numerical robustness, low-dissipation, and superior computational efficiency. Specifically, benefited from the high-resolution shock sensor which can accurately perceive shocks without excessive misidentifications, the hybrid scheme can achieve non-oscillatory solutions, and resolve more vortices in smooth regions compared to the original shock-capturing scheme. Meanwhile, the superiority of the hybrid scheme is further confirmed in the Reynolds-averaged Navier–Stokes equations/Lager Eddy Simulations (RANS/LES) for the DLR scramjet combustor case with viscous terms and/or sub-grid scale models are used. The present hybrid framework can be easily implemented within the existing numerical simulation code framework.
RECENT ADVANCES IN BOND-RESOLVED SCANNING TUNNELING MICROSCOPY
Authors: SONG SHAOTANG , SU JIE , PENG XINNAN , WU XINBANG , TELYCHKO MYKOLA
Published: February 2021

Recent advances in bond-resolved scanning tunneling microscopy (BRSTM) have demonstrated the tremendous potential of this characterization technique to attain an ultra-high spatial resolution at the level of a single chemical bond. Due to such a unique ability to visualize chemical bonds, BRSTM has been recognized as a valuable characterization tool in the rapidly developing field of on-surface chemistry. In this paper, we discuss the recent experimental advances in BRSTM imaging techniques and their applications in the characterization of a wide scope of functional nanostructures, including individual molecules, elusive nanographenes fabricated by means of surface-assisted synthetic strategies and extended supramolecular self-assemblies.
INFLUENCE OF MOLECULE MODIFICATION AND LINKING GROUP ON ELECTRONIC TRANSPORT IN MOLECULAR DEVICES
Authors: WU YAMIN , BIAN BAOAN , LIAO BIN , WANG GUOLIANG
Published: February 2021

We investigated the effect of molecule modification and linking group on the electronic transports in salicylidene aniline-based molecular devices by first-principles calculation. The devices with cis and trans configurations exhibit a switching effect. The different molecule modification and linking group induce different electronic transports. The linking groups thienylthiol and phenylthiol reduce the current of devices with cis and trans configurations. The group –NH2 is used to modify the molecule enhances the currents of devices with cis and trans configurations, and the –NO2 enhances the current of device with cis configuration and reduces the current of device with trans configuration. Both the molecule modification and changed linking group suppress the switching ratio. The results suggest that the electronic transport can be modulated by modifying molecule and changing linking group. Especially, the molecule modification can improve the current of molecular device.
“Entanglement” and the Exploitation of Common Pool Resources: A Quantum Solution to the Prisoner’s Dilemma
Authors: Mamada Robert , Perrings Charles
Published: February 2021

The overexploitation of common pool resources is frequently associated with open access regimes in which each resource user operates independently of all other resource users. The outcome is a Nash equilibrium of the prisoner’s dilemma. Restricted access regimes of the sort identified by Ostrom and colleagues typically ensure that individual resource users do not operate independently. Taking a quantum approach to the theory of games, we argue that the institutional arrangements involved in common pool resource management imply the “entanglement” of the strategies of resource users. For a very simple case — two firms exploiting a common pool fishery — we show that there exists an “entanglement” mechanism that assures the cooperative outcome.
Analysis of Damages in Layered Surrounding Rocks Induced by Blasting During Tunnel Construction
Authors: Ma Long Hao , Jiang Xiang , Chen Jie , Zhao Yun Feng , Liu Rong , Ren Song
Published: February 2021

A layered rock mass is a special type of geological body. The existence of a bedding surface may lead to a poor cutting effect (over/under-excavation of the surrounding rock), falling of blocks, or collapse, thereby affecting most constructions in areas with such rocks. Given the lack of a proper quantitative analysis method for surrounding rock damages, the construction process of layered surrounding rock tunnels becomes difficult. To address these problems, three types of cut blasting models with single, double, and four holes are studied in this paper. With this, the LS-DYNA program is used to analyze the behaviors of stress wave propagation, crack propagation, and fracture modes, as well as fracture mechanisms of mudstone, sandstone, and layered rock. Using the image processing technology and fractal theory, the fractal dimension change trend and progressive damage evolution behavior of the three types of rocks under different cut blasting conditions are determined. Also determined is the corresponding relationship between the fractal dimension and the rock damage degree. The results indicate that crack initiation, propagation, bifurcation, and fractal dimension evolution are more closely related to the phenomenon where the compression wave is ahead of the tension wave, and the[Formula: see text]incompatible deformation of the bedding under single-hole blasting. Under double-hole and four-hole blasting, the phenomena, such as spalling, bedding crack penetration, and fracture connection between the explosive holes are caused mainly by the effects of stress concentration, reflected tension waves, and stress wave superposition. Moreover, under different blasting conditions, the rocks exhibit a similar progressive damage process, i.e. a rapid increase at first, then a slow rise, and finally a stabilization phase. The dynamic damage degree of the rock exhibits a linear increasing trend under different blasting holes. The study results provide a useful reference for blasting scheme design and optimization of underground engineering projects.
Some new results on skew inverse Laurent series rings
Authors: Paykan Kamal
Published: February 2021

Let [Formula: see text] be an associative ring equipped with an automorphism [Formula: see text] and an [Formula: see text]-derivation [Formula: see text]. Necessary and sufficient conditions are obtained for the skew inverse Laurent series ring [Formula: see text] to satisfy a certain ring property which is among being local, semilocal, semiperfect and semisimple, respectively. We also give a characterization of the cleanness of the ring [Formula: see text].
Class-preserving automorphisms of certain HNN extensions
Authors: Zhou Wei , Kim Goansu
Published: February 2021

We consider HNN extensions [Formula: see text], where [Formula: see text] are normal subgroups of [Formula: see text] and [Formula: see text]. We show that class-preserving automorphisms of those HNN extensions are all inner if [Formula: see text] satisfies certain conditions. From Grossman’s result, it follows that outer automorphism groups of such conjugacy separable HNN extensions are residually finite.
HOW BEHAVIOR OF USERS IMPACTS THE SUCCESS OF ONLINE Q&A COMMUNITIES
Authors: YU FAN , JANSSEN MARCO A.
Published: February 2021

What makes Question & Answer (Q&A) communities productive? In this paper, we look into how the diversity of behavioral types of agents impacts the performance of Q&A communities using different performance metrics. We do this by developing an agent-based model informed by insights from previous studies on Q&A communities. By analyzing the different strategies for how questions are selected to answer, we find that there are mixtures of strategies leading to the best outcomes for different performance conditions. Particularly, Q&A communities that encourage participants to focus on answering the new questions reach the best performance in answering the questions, creating the long term value, and improving the competence of solving difficulty. In conclusion, we find that the current strategies of question selection on Stack Overflow are in line with the high performance of producing public benefit from the collective attention available.
On groups Gnk and Γnk: A study of manifolds, dynamics, and invariants
Authors: Manturov Vassily O. , Fedoseev Denis A. , Kim Seongjeong , Nikonov Igor M.
Published: February 2021

Recently, the first named author defined a 2-parametric family of groups [Formula: see text] [V. O. Manturov, Non–reidemeister knot theory and its applications in dynamical systems, geometry and topology, preprint (2015), arXiv:1501.05208]. Those groups may be regarded as analogues of braid groups.

Study of the connection between the groups [Formula: see text] and dynamical systems led to the discovery of the following fundamental principle: “If dynamical systems describing the motion of [Formula: see text] particles possess a nice codimension one property governed by exactly [Formula: see text] particles, then these dynamical systems admit a topological invariant valued in [Formula: see text]”.

The [Formula: see text] groups have connections to different algebraic structures, Coxeter groups, Kirillov-Fomin algebras, and cluster algebras, to name three. Study of the [Formula: see text] groups led to, in particular, the construction of invariants, valued in free products of cyclic groups. All generators of the [Formula: see text] groups are reflections which make them similar to Coxeter groups and not to braid groups. Nevertheless, there are many ways to enhance [Formula: see text] groups to get rid of this [Formula: see text]-torsion.

Later the first and the fourth named authors introduced and studied the second family of groups, denoted by [Formula: see text], which are closely related to triangulations of manifolds.

The spaces of triangulations of a given manifolds have been widely studied. The celebrated theorem of Pachner [P.L. homeomorphic manifolds are equivalent by elementary shellings, Europ. J. Combin. 12(2) (1991) 129–145] says that any two triangulations of a given manifold can be connected by a sequence of bistellar moves or Pachner moves. See also [I. M. Gelfand, M. M. Kapranov and A. V. Zelevinsky, Discriminants, Resultants, and Multidimensional Determinants (Birkhäuser, Boston, 1994); A. Nabutovsky, Fundamental group and contractible closed geodesics, Comm. Pure Appl. Math. 49(12) (1996) 1257–1270]; the [Formula: see text] naturally appear when considering the set of triangulations with the fixed number of points.

There are two ways of introducing the groups [Formula: see text]: the geometrical one, which depends on the metric, and the topological one. The second one can be thought of as a “braid group” of the manifold and, by definition, is an invariant of the topological type of manifold; in a similar way, one can construct the smooth version.

In this paper, we give a survey of the ideas lying in the foundation of the [Formula: see text] and [Formula: see text] theories and give an overview of recent results in the study of those groups, manifolds, dynamical systems, knot and braid theories.
Minimally Invasive Treatments of Dupuytren Disease: An Overview
Authors: Yeo Ji Hyun , Kim Jin Young
Published: February 2021

Dupuytren disease (DD) is a fibroproliferative disorder that originates at the palmar fascia and results in flexion contracture of the digits. The gold standard treatment for DD has been surgery. Surgical treatment of DD can be done with various methods, from percutaneous needle fasciotomy to dermatofasciectomy. The most commonly used surgical treatment is limited fasciectomy (LF). The potential complications of limited fasciectomy include long recovery time, scarring, neurovascular injury, and tendon injury. Minimally invasive treatment for DD, which is simple and allows for rapid return of function, has gained popularity amongst both patients and surgeons. Currently, minimally invasive treatments for DD include percutaneous needle fasciotomy (PNF) and collagenase clostridium histolyticum (CCH). In this review, we provide an overview of the minimally invasive treatments for Dupuytren disease and summarize the current evidence regarding these minimally invasive treatments.
The Hydrogen Electrode Reaction in the Anion Exchange Membrane Fuel Cell
Authors: Carlson Annika , Grimler Henrik , Ekström Henrik , Lagergren Carina , Lindström Rakel Wreland , Lindbergh Göran
Published: February 2021

The hydrogen electrode in the anion-exchange membrane fuel cell needs further attention to understand the overall cell limitations. In this study, electrochemical impedance spectroscopy and galvanodynamic measurements in combination with a physics-based model are used to determine the kinetic parameters of the hydrogen oxidation reaction and hydrogen evolution reaction on Pt/C porous gas-diffusion electrodes in an AEMFC. Two semicircles are observed in the Nyquist plot of a symmetrical AEM hydrogen cell, indicating a two‑step reaction pathway. The fit of the model shows that the Tafel-Volmer pathway describes the kinetics better than the Heyrovsky-Volmer pathway. The reaction rates of the adsorption and charge transfer steps are similar in magnitude implying that both need consideration during modeling and evaluation of the hydrogen electrode. Furthermore, the performance is limited also by the ionic conductivity in the electrode. Comparison of the impedance of the HOR and a hydrogen/oxygen AEMFC indicates that the low-frequency semicircle is mainly associated with the oxygen reduction reaction and the cathode, while the high-frequency semicircle is likely related to a combination of the anode and the cathode. Based on this work, a platform for further studies of losses and total impedance of operating AEMFC has been created.
Effect of Complexing Agents on Surface Composition for Co Post-CMP Cleaning Process
Authors: Byun Jinuk , Bae KiHo , Kwon Ohsung , Myong Kyong Kyu , Lim Taeho , Kim Jae Jeong
Published: February 2021

The effect of surface composition change based on complexing agents on cobalt (Co) post-chemical mechanical polishing cleaning (cleaning) is investigated. The change in chemical composition of the Co surface significantly affects Co cleaning performance, as well as dissolution capacity of the complexing agent and pH of cleaning solution. Oxide composition of the Co surface was manipulated using different types of complexing agents. Addition of citric acid and glycine in cleaning solution resulted in predominant formation of Co3O4 and CoOOH on the Co surface, respectively. The citric acid-derived Co3O4 surface embraces abundant –O– terminates, which attracts the complexing agent and silica abrasive relatively weakly, resulting in suppression of recess formation and reduction of surface particle residue after cleaning. On the contrary, the –OH terminated CoOOH surface formed by glycine bound strongly with silica. Therefore, preferential development of Co3O4 on the surface considerably enhances Co cleaning performance, which is achieved by introducing citric acid in the cleaning solution. To sum up, we suggested an unconventional insight to understand the effect of Co surface chemical state on cleaning performance.
Probing the Mechanisms of Metal CMP Using Tribo-Electroanalytical Measurements: Results for a Copper/Malonate System
Authors: Wei S. , Johnson C. A. , Roy D.
Published: February 2021

The experiments reported in this work explore certain fundamental mechanistic aspects of assessing slurry formulations for chemical mechanical planarization (CMP), an important processing step of integrated circuit (IC) fabrication. We use a model system involving abrasive-free planarization of copper (wiring material in ICs) with a pH-varied (∼6–10) CMP slurry containing malonic acid (MA, a complexer) and sodium percarbonate (an oxidizer). The analytical protocols necessary to probe such a CMP system are illustrated by combining linear sweep voltammetry (LSV), open circuit potential (OCP) transients, chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS), all operated under tribological controls of CMP. LSV helps to establish the CMP enabling reaction mechanisms. The information obtained from transient data of OCP and CA is incorporated in a phenomenological model of tribo-corrosion to further corroborate the CMP mechanism. EIS provides further verification and more details of the CMP reactions. Cu removal rates increase with increasing concentrations (0.0–0.10 M) of MA, and in agreement with a proposed CMP mechanism, exhibit a correlation with the rates of tribo-corrosion. The results illustrate a quantitative diagnostic framework for studying CMP mechanisms in the tribo-electroanalytical approach.
Effect of Using High-Pressure Gas Atmosphere with UV Photocatalysis on the CMP Characteristics of a 4H-SiC Substrate
Authors: Yin Tao , Zhao Panpan , Doi Toshiro , Kurokawa Syuhei , Jiang Jinyun
Published: February 2021

The objective of this study was to realize high-efficiency and high-quality chemical mechanical polishing (CMP) of a silicon carbide (SiC) substrate. Consequently, the effect of a gas atmosphere on the CMP characteristics of a SiC substrate was investigated. The experimental results show that increasing the partial pressure of oxygen (O2) in the atmosphere to 300 kPa led to an over 2-fold increase in the material removal rates (MRRs) of the Si and carbon (C) faces compared to an open-air atmosphere. White light interference microscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were used to analyze the face morphology and surface elements after processing. Si face atoms were more difficult to oxidize than C face atoms, resulting in a low MRR of the Si face after CMP. The MRR of the Si face was improved by using an ultraviolet (UV) photocatalysis reaction in the high-pressure O2 atmosphere. Excitation of O2 molecules in the slurry into HO

2

• with a stronger oxidation capability promoted the chemical reaction at the solid-liquid interface. The processing mechanism was elucidated.
Antenatal betamethasone redistributes central blood flows and preferentially augments right ventricular output and pump function in preterm fetal lambs
Authors: Smolich Joseph J. , Mynard Jonathan P.
Published: February 2021

The glucocorticosteroid betamethasone, which is routinely administered prior to anticipated preterm birth to enhance maturation of the lungs and the cardiovascular system, has diverse fetal regional blood flow effects ranging from increased pulmonary flow to decreased cerebral flow. The aim of this study was to test the hypothesis that these diverse effects reflect alterations in major central flow patterns that are associated with complementary shifts in left ventricular (LV) and right ventricular (RV) pumping performance. Studies were performed in anesthetized preterm fetal lambs (gestation = 127 ± 1 days, term = 147 days) with ( n = 14) or without ( n = 12) preceding betamethasone treatment via maternal intramuscular injection. High-fidelity central arterial blood pressure and flow signals were obtained to calculate LV and RV outputs and total hydraulic power. Betamethasone therapy was accompanied by 1) increased RV, but not LV, output; 2) a greater RV than LV increase in total power; 3) a redistribution of LV output away from the fetal upper body region and toward the lower body and placenta; 4) a greater proportion of RV output passing to the lungs, and a lesser proportion to the lower body and placenta; and 5) a change in the relative contribution of venous streams to ventricular filling, with the LV having increased pulmonary venous and decreased foramen ovale components, and the RV having lesser superior vena caval and greater inferior vena caval portions. Taken together, these findings suggest that antenatal betamethasone produces a widespread redistribution of central arterial and venous flows in the fetus, accompanied by a preferential rise in RV pumping performance.
An open-source program to analyze spontaneous sympathetic neurohemodynamic transduction
Authors: O’Brien Myles W. , Petterson Jennifer L. , Kimmerly Derek S.
Published: February 2021

The pressor responses to spontaneous bursts of muscle sympathetic nerve activity provide important information regarding sympathetic regulation of the circulation. Many laboratories worldwide quantify sympathetic neurohemodynamic transduction using in-house, customized software requiring high-level programming skills and/or costly computer programs. To overcome these barriers, this study presents a simple, open-source, Microsoft Excel-based analysis program along with video instructions to assist researchers without the necessary resources to quantify sympathetic neurohemodynamic transduction.
Friction is preferred over grasp configuration in precision grip grasping
Authors: Klein Lina K. , Maiello Guido , Fleming Roland W. , Voudouris Dimitris
Published: February 2021

When grasping an object, humans can place their fingers at several positions on its surface. The selection of these endpoints depends on many factors, with two of the most important being grasp stability and grasp configuration. We put these two factors in conflict and examine which is considered more important. Our results highlight that humans are not reluctant to adopt unusual grasp configurations to satisfy grasp stability.
Spinal cord fractalkine (CX3CL1) signaling is critical for neuronal sensitization in experimental nonspecific, myofascial low back pain
Authors: Sessler Katharina , Blechschmidt Vivian , Hoheisel Ulrich , Mense Siegfried , Schirmer Lucas , Treede Rolf-Detlef
Published: February 2021

Blocking fractalkine signaling by neutralizing antibodies completely prevented spinal sensitization induced by repetitive mild nociceptive input [2 nerve growth factor (NGF) injections into the multifidus muscle] Conversely, fractalkine given intrathecally caused the same pattern of spinal sensitization as the nociceptive NGF injections. Fractalkine signaling is critically involved in sensitization of dorsal horn neurons induced by repeated nociceptive low back muscle stimulation and may hence be a potential target for the prevention of nonspecific, myofascial low back pain.
Differences in brain structure and theta burst stimulation-induced plasticity implicate the corticomotor system in loss of function after musculoskeletal injury
Authors: Flanagan Shawn D. , Proessl Felix , Dunn-Lewis Courtenay , Sterczala Adam J. , Connaboy Chris , Canino Maria C. , Beethe Anne Z. , Eagle Shawn R. , Szivak Tunde K. , Onate James A. , Volek Jeff S. , Maresh Carl M. , Kaeding Christopher C. , Kraemer William J.
Published: February 2021

Traumatic musculoskeletal injuries may involve adaptive changes in the brain that contribute to loss of function. Our combination of neuroimaging and theta burst transcranial magnetic stimulation (iTBS) revealed distinct patterns of iTBS-induced plasticity that normalized differences in muscle and brain function evident years after unilateral knee ligament rupture. Individual responses to iTBS corresponded to injury-specific differences in brain structure and physiological activity, depended on skeletomotor deficit severity, and suggested that corticomotor adaptations involve both hemispheres.
Yeast Two-Hybrid Systems and Protein Interaction Mapping Projects for Yeast and Worm
Authors: Walhout Albertha J. M. , Boulton Simon J. , Vidal Marc
Published: February 2021

The availability of complete genome sequences necessitates the development of standardized functional assays to analyse the tens of thousands of predicted gene products in high-throughput experimental settings. Such approaches are collectively referred to as ‘functional genomics’. One approach to investigate the properties of a proteome of interest is by systematic analysis of protein–protein interactions. So far, the yeast two-hybrid system is the most commonly used method for large-scale, high-throughput identification of potential protein–protein interactions. Here, we discuss several technical features of variants of the two-hybrid systems in light of data recently obtained from different protein interaction mapping projects for the budding yeast Saccharomyces cerevisiae and the nematode Caenorhabditis elegans.
Pathogen Special: Vibrio cholerae, Pseudomonas aeruginosa and Xylella fastidiosa
Authors: Wixon Jo
Published: February 2021

One could almost say that it is the latest fashion to sequence a bacterial genome. However, this would belittle the efforts of those working on these important organisms, whose data will greatly help those working on the prevention of disease in the fields of medicine and agriculture. In this feature we present a guided tour of the latest additions to the ‘sequenced microbes’ club. Vibrio cholerae is the causative agent of cholera, which is still a threat in countries with poor sanitation and unsafe drinking water. Pseudomonas aeruginosa is responsible for a large proportion of opportunistic human infections, typically infecting those with compromised immune systems, particularly cystic fibrosis patients, those patients on respirators and burn victims. Xylella fastidiosa is a plant pathogen that attacks citrus fruits by blocking the xylem, resulting in juiceless fruits of no commercial value.
Insights into the Structural and Functional Evolution of Plant Genomes Afforded by the Nucleotide Sequences of Chromosomes 2 and 4 of Arabidopsis thaliana
Authors: Bancroft Ian
Published: February 2021

The rapidly accumulating genome sequence data from the plant Arabidopsis thaliana allows more detailed analysis of genome content and organisation than ever bafore possible in plants. The genome shows a surprisingly high level of genetic redundancy, with as many as 75% of gene products showing signficant homology to another protien of A. thaliana. Many duplicated genes occur in arrays of conserved order and indicate that A. thaliana is likely to have had a tetraploid ancestor. Analysis of the divergence of duplicated genome segments leads to the prediction of two major modes of plant genome evolution: macro-scale duplication and rearrangement of chromosomes and micro-scale translocation, duplication and loss of individual genes or small groups of genes.
Global cDNA Amplification Combined with Real-Time RT–PCR: Accurate Quantification of Multiple Human Potassium Channel Genes at the Single Cell Level
Authors: Al-Taher A. , Bashein A. , Nolan T. , Hollingsworth M. , G. Brady
Published: February 2021

We have developed a sensitive quantitative RT–PCR procedure suitable for the analysis of small samples, including single cells, and have used it to measure levels of potassium channel mRNAs in a panel of human tissues and small numbers of cells grown in culture. The method involves an initial global amplification of cDNA derived from all added polyadenylated mRNA followed by quantitative RT–PCR of individual genes using specific primers. In order to facilitate rapid and accurate processing of samples, we have adapted the approach to allow use of TaqMan™ real-time quantitative PCR. We demonstrate that the approach represents a major improvement over existing conventional and real-time quantitative PCR approaches, since it can be applied to samples equivalent to a single cell, is able to accurately measure expression levels equivalent to less than 1/100th copy/cell (one specific cDNA molecule present amongst 108 total cDNA molecules). Furthermore, since the initial step involves a global amplification of all expressed genes, a permanent cDNA archive is generated from each sample, which can be regenerated indefinitely for further expression analysis.