bluuebunny/crossref_metadata_2025 huggingface dataset:
Motivators and deterrents for early career female doctors applying to surgical training programmes in the UK National Health Service: a mixed-methods study
Authors: Ruparell Kajal , Barve Rajas , Tas Rukiye N , Chen Sihan , Mclaughlin Reed , Ravendren Andrew , Gupte Chinmay M
Published: December 2022

Objectives

To perform a mixed-methods study identifying motivators and deterrents to female doctors interested in core surgical training (CST). To provide tangible implementations based on the findings.

Design

This study used quantitative (questionnaires) and qualitative (semistructured interviews (SSIs)) analyses. Participants completed online questionnaires on Qualtrics and SSIs were conducted remotely on Microsoft Teams. Questions were derived from previous studies and a novel term, the gender impact rating (GIR), was coined to assess the impact of gender on opportunities available during CST application.

Setting

Participants were working in the UK National Health Service and data collected from December 2020 to January 2021.

Participants

A total of 100 female surgical trainees in the UK ranging from Foundation Year 2 to Core Training Year 2.

Main outcome measures

Participants ranked factors by their influence on their CST application. Of the 100 trainees, 21 were randomly selected for an SSI to explore their questionnaire responses. Statistical analyses were performed using MATLAB and SPSS, alongside a thematic analysis of the interviews.

Results

A total of 44 out of 100 questionnaire respondents ranked early exposure to surgery as the most influential motivator, while 43% selected work-life balance as the greatest deterrent and 33% suggested mentoring schemes to encourage women to apply to CST. The median GIR was 3 out of 5, indicating a moderate perceived impact of gender on opportunities available during CST application. Qualitative analysis found four overarching themes: institutional factors (including mentorship schemes), organisational culture (including active engagement), social factors and personal factors.

Conclusion

Thematic analysis suggested that seniors involving women in theatre and a supportive work environment would encourage entry of more female surgeons. Therefore, the proposed implementations are the active engagement of women in theatre and destigmatising less than full-time training. Further research into ethnicity and personality on motivations to enter surgery is advised.
Determination of biomarkers associated with neoadjuvant treatment response focusing on colibactin-producingEscherichia coliin patients with mid or low rectal cancer: a prospective clinical study protocol (MICARE)
Authors: Taoum Christophe , Carrier Guillaume , Jarlier Marta , Roche Gwenaelle , Gagniere Johan , Fiess Catherine , De forges Helene , Chevarin Caroline , Colombo Pierre-Emmanuel , Barnich Nicolas , Rouanet Philippe , Bonnet Mathilde
Published: December 2022

Introduction

The management of mid and low rectal cancer is based on neoadjuvant chemoradiotherapy (CRT) followed by standardised surgery. There is no biomarker in rectal cancer to aid clinicians in foreseeing treatment response. The determination of factors associated with treatment response might allow the identification of patients who require tailored strategies (eg, therapeutic de-escalation or intensification). Colibactin-producingEscherichia coli(CoPEC) has been associated with aggressive colorectal cancer and could be a poor prognostic factor. Currently, no study has evaluated the potential association between intestinal microbiota composition and tumour response to CRT in mid and low rectal cancer. The aim of this study is to assess the association between response to neoadjuvant CRT and faecal intestinal microbiota composition and/or CoPEC prevalence in patients with mid or low rectal cancer.

Methods and analysis

This is a non-randomised bicentric prospective clinical study with a recruitment capacity of 200 patients. Three stool samples will be collected from participants with histological-proven adenocarcinome of mid or low rectum who meet eligibility criteria of the study protocol: one before neoadjuvant treatment start, one in the period between CRT end and surgery and one the day before surgery. In each sample, CoPEC will be detected by culture in special media and molecular (PCR) approaches. The global microbiota composition will be also assessed by the bacterial 16S rRNA gene sequencing. Neoadjuvant CRT response and tumour regression grade will be described using the Dworak system at pathological examination. Clinical data and survival outcomes will also be collected and investigated.

Ethics and dissemination

MICARE was approved by the local ethics committee (Comité de Protection des Personnes Sud-Est II, 18 December 2019. Reference number 2019-A02493-54 and the institutional review board. Patients will be required to provide written informed consent. Results will be published in a peer reviewed journal.

Trial registration number

NCT04103567.
Practical Anemia Bundle for Sustained Blood Recovery (PABST-BR) in critical illness: a protocol for a randomised controlled trial
Authors: Warner Matthew A , Go Ronald S , Schulte Phillip J , Beam William B , Charnin Jonathan E , Meade Laurie , Droege Kim A , Anderson Brenda K , Johnson Matthew L , Karon Brad , Cheville Andrea , Gajic Ognjen , Kor Daryl J
Published: December 2022

Introduction

Anaemia is highly prevalent in critical illness and is associated with impaired outcomes during and after hospitalisation. However, the impact of interventions designed to attenuate or treat anaemia during critical illness on post-hospitalisation haemoglobin recovery and functional outcomes is unclear.

Methods and analysis

The Practical Anemia Bundle for Sustained Blood Recovery (PABST-BR) clinical trial is a pragmatic, open-label, parallel group, single-centre, randomised clinical trial assessing the impact of a multifaceted anaemia prevention and treatment strategy versus standard care for improvement of haemoglobin concentrations and functional outcomes after critical illness. The intervention, which will be delivered early in critical illness for those with moderate-to-severe anaemia (ie, haemoglobin <100 g/L), includes three components: (1) optimised phlebotomy, (2) clinical decision support and (3) pharmacological anaemia treatment directed at the underlying aetiology of anaemia. In-person assessments will occur at 1 and 3 months post-hospitalisation for laboratory evaluations and multidimensional functional outcome assessments. The primary outcome is differences in haemoglobin concentrations between groups, with secondary endpoints of anaemia-related fatigue, physical function, cognition, mental health, quality of life, phlebotomy volumes and frequency, transfusions, readmissions and mortality through 1-year post-hospitalisation.

Ethics and dissemination

The study has been approved by the Institutional Review Board of the Mayo Clinic in Minnesota, USA. A Data Safety Monitoring Plan has been created in accordance with the policies of the Institutional Review Board and the study funder, the National Heart, Lung and Blood Institute of the National Institutes of Health (NIH). The study will comply with NIH data sharing and dissemination policies. Results will be presented at national and international meetings and published in peer-reviewed journals. Designing and testing strategies to optimise haemoglobin recovery and improve functional outcomes after critical illness remain important research gaps. The PABST-BR trial will inform the development of a larger multicentre clinical trial.

Trial registration number

NCT05167734.
COVID-19 in a tertiary paediatric centre in Portugal: a single-centre
retrospective study
Authors: Silva Tiago Milheiro , Garcia Ana Margarida , Gouveia Catarina , Candeias Flora , Brito Maria João
Published: December 2022

Objective

To describe the demographic, clinical, laboratory and imaging
features of the first 300 SARS-CoV-2-infected children presenting to a
tertiary paediatric centre in Portugal.

Design

Single-centre, retrospective, descriptive study of paediatric
patients who had a confirmed SARS-CoV-2 infection from 7 March to 20
September 2020.

Setting

Tertiary paediatric referral centre (Hospital Dona Estefânia,
Lisbon, Portugal).

Patients

18 years or younger.

Main outcome measures

Incidence, mortality, age of infection, clinical characteristics,
treatment prescribed and outcome.

Results

Three hundred patients with confirmed COVID-19 presented to the
centre. One hundred and seventeen (39%) patients were admitted to the
hospital: 69 with COVID-19 and 48 for other reasons. The most common
symptoms in children admitted with COVID-19 were fever (49) and cough
(38). Six patients required intensive care. Two children died and seven
reported short-term sequelae.

Conclusions

COVID-19 is usually a mild disease in children, but a small
proportion of patients develop severe and critical disease. Fatal
outcomes were rare and only occurred in children with severe previous
medical conditions.
In situ vaccination with cowpea mosaic virus elicits systemic antitumor immunity and potentiates immune checkpoint blockade
Authors: Mao Chenkai , Beiss Veronique , Ho Gregory W , Fields Jennifer , Steinmetz Nicole F , Fiering Steven
Published: December 2022

Background

In situ vaccination (ISV) is a cancer immunotherapy strategy in which immunostimulatory reagents are introduced directly into a tumor to stimulate antitumor immunity both against the treated tumor and systemically against untreated tumors. Recently, we showed that cowpea mosaic virus (CPMV) is a potent multi-toll-like receptor (TLR) agonist with potent efficacy for treating tumors in mice and dogs by ISV. However, ISV with CPMV alone does not uniformly treat all mouse tumor models tested, however this can be overcome through strategic combinations. More insight is needed to delineate potency and mechanism of systemic antitumor immunity and abscopal effect.

Method

We investigated the systemic efficacy (abscopal effect) of CPMV ISV with a two-tumor mouse model using murine tumor lines B16F10, 4T1, CT26 and MC38. Flow cytometry identified changes in cell populations responsible for systemic efficacy of CPMV. Transgenic knockout mice and depleting antibodies validated the role of relevant candidate cell populations and cytokines. We evaluated these findings and engineered a multicomponent combination therapy to specifically target the candidate cell population and investigated its systemic efficacy, acquired resistance and immunological memory in mouse models.

Results

ISV with CPMV induces systemic antitumor T-cell-mediated immunity that inhibits growth of untreated tumors and requires conventional type-1 dendritic cells (cDC1s). Furthermore, using multiple tumor mouse models resistant to anti-programmed death 1 (PD-1) therapy, we tested the hypothesis that CPMV along with local activation of antigen-presenting cells with agonistic anti-CD40 can synergize and strengthen antitumor efficacy. Indeed, this combination ISV strategy induces an influx of CD8+T cells, triggers regression in both treated local and untreated distant tumors and potentiates tumor responses to anti-PD-1 therapy. Moreover, serial ISV overcomes resistance to anti-PD-1 therapy and establishes tumor-specific immunological memory.

Conclusions

These findings provide new insights into in situ TLR activation and cDC1 recruitment as effective strategies to overcome resistance to immunotherapy in treated and untreated tumors.
Exploring the utility of assistive artificial intelligence for ultrasound scanning in regional anesthesia
Authors: Bowness James Simeon , El-Boghdadly Kariem , Woodworth Glenn , Noble J Alison , Higham Helen , Burckett-St Laurent David
Published: December 2022

Introduction

Ultrasound-guided regional anesthesia (UGRA) involves the acquisition and interpretation of ultrasound images to delineate sonoanatomy. This study explores the utility of a novel artificial intelligence (AI) device designed to assist in this task (ScanNav Anatomy Peripheral Nerve Block; ScanNav), which applies a color overlay on real-time ultrasound to highlight key anatomical structures.

Methods

Thirty anesthesiologists, 15 non-experts and 15 experts in UGRA, performed 240 ultrasound scans across nine peripheral nerve block regions. Half were performed with ScanNav. After scanning each block region, participants completed a questionnaire on the utility of the device in relation to training, teaching, and clinical practice in ultrasound scanning for UGRA. Ultrasound and color overlay output were recorded from scans performed with ScanNav. Experts present during the scans (real-time experts) were asked to assess potential for increased risk associated with use of the device (eg, needle trauma to safety structures). This was compared with experts who viewed the AI scans remotely.

Results

Non-experts were more likely to provide positive and less likely to provide negative feedback than experts (p=0.001). Positive feedback was provided most frequently by non-experts on the potential role for training (37/60, 61.7%); for experts, it was for its utility in teaching (30/60, 50%). Real-time and remote experts reported a potentially increased risk in 12/254 (4.7%) vs 8/254 (3.1%, p=0.362) scans, respectively.

Discussion

ScanNav shows potential to support non-experts in training and clinical practice, and experts in teaching UGRA. Such technology may aid the uptake and generalizability of UGRA.

Trial registration number

NCT04918693.
A New Four-Dimensional Chaotic System with Multistability and Its Predefined-Time Synchronization
Authors: Wang Ertong , Yan Shaohui , Wang Qiyu
Published: December 2022

A new chaotic system is obtained by modifying the Sprott-C system. Then the phase diagrams, power spectra, 0–1 tests, Poincaré maps, Lyapunov exponential spectra, time sequences, and complexity are studied. Research indicates that the system is sensitive to parameters and initial conditions, and bursting oscillation, transient chaos and multistability are investigated. The complexity of the new system is calculated using the Sample Entropy (SE) complexity algorithm, including selecting more suitable initial values and parameters for the application. In addition, the system circuit designed by Multisim and the actual digital circuit realized by Field Programmable Gate Array (FPGA) verify the feasibility of the system. Finally, to obtain a more appropriate synchronization result for practical applications, a synchronous controller is designed to successfully implement the predefined-time synchronization of the system in different dimensions. The simulation results demonstrate that the predefined-time synchronization can control the synchronous time and is unaffected by the initial conditions. The results demonstrate that this synchronization method is well accommodated to practical applications.
Chaotic Dynamics of a Periodically Forced Duffing Oscillator with Cubic Quintic Septic Power Nonlinearities
Authors: Remmi S. K. , Latha M. M.
Published: December 2022

In this paper, we investigate the chaotic dynamics of Cubic Quintic Septic Duffing oscillator. The conditions of the system parameters for the existence of fixed points and the stability of the undamped free Cubic Quintic Septic Duffing oscillator are obtained. Multiple scales method is employed to determine the various resonance states of the system through frequency-amplitude response curves. Using linear damping, septic coefficient, excitation amplitude and excitation frequency as control parameters, the bifurcation diagrams are drawn numerically and the results are confirmed using phase space trajectories and their corresponding Poincaré sections. The influence of septic nonlinearity, linear damping and excitation amplitude in controlling the chaotic behavior of the system is also investigated.
Multiscroll in Bidirectionally Coupled Jerk Oscillators: Theoretical Analysis and PSpice Verification
Authors: Mekak-Egong Hermann-Dior , Ramakrishnan Balamurali , Telem Adélaïde Nicole Kengnou , Rajagopal Karthikeyan , Kengne Jacques
Published: December 2022

It is known that the unidirectional coupling between a double-scroll system (drive) in the oscillation regime with another system (response) in the steady-state, gives rise to more complex dynamics such as multiscroll attractors [Dana et al., 2008]. This paper shows the way to move from n-scroll to 2n-scroll in a bidirectional coupling scheme between two jerk oscillators. The coupling considered can be interpreted as a perturbation to each oscillator’s amplitude through a signal proportional to the amplitude of the other. Indeed, starting from a situation of two oscillators which can generate double-scroll dynamics individually, we perform a bidirectional coupling of both oscillators which results in more complex dynamics such as multistability and 4-scroll chaotic attractor in the coupled system (not observed in an isolated oscillator). The underlined coupling scheme provides an efficient method for generating higher-order multiscroll attractors. The route to the 4-scroll chaotic attractor is explained with the help of bifurcation diagrams, plots of several phase portraits, and basins of attractions. Indirect validation of the theoretical analysis is carried out by using the PSpice simulation software.
A Collective Colony Migration Model with Hill Functions in Recruitment
Authors: Wang Lisha , Qiu Zhipeng , Kang Yun
Published: December 2022

Social insect colonies’ robust and efficient collective behaviors without any central control contribute greatly to their ecological success. Colony migration is a leading subject for studying collective decision-making in migration. In this paper, a general colony migration model with Hill functions in recruitment is proposed to investigate the underlying decision making mechanism and the related dynamical behaviors. Our analysis provides the existence and stability of equilibrium, and the global dynamical behavior of the system. To understand how piecewise functions and Hill functions in recruitment impact colony migration dynamics, the comparisons are performed in both analytic results and bifurcation analysis. Our theoretical results show that the dynamics of the migration system with Hill functions in recruitment differs from that of the migration system with piecewise functions in the following three aspects: (1) all population components in our colony migration model with Hill functions in recruitment are persistent; (2) the colony migration model with Hill functions in recruitment has saddle and saddle-node bifurcations, while the migration system with piecewise functions does not; (3) the system with Hill functions has only equilibrium dynamics, i.e. either has a global stability at one interior equilibrium or has bistablity among two locally stable interior equilibria. Bifurcation analysis shows that the geometrical shape of the Hill functions greatly impacts the dynamics: (1) the system with flatter Hill functions is less likely to exhibit bistability; (2) the system with steeper functions is prone to exhibit bistability, and the steady state of total active workers is closer to that of active workers in the system with piecewise function.
Nontrivial Limit Cycles in a Kind of Piecewise Smooth Generalized Abel Equation
Authors: Zhao Qianqian , Yu Jiang , Wang Cheng
Published: December 2022

In this paper, we focus on the number of nontrivial limit cycles in a kind of piecewise smooth generalized Abel equation [Formula: see text]

where [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Under the condition [Formula: see text], employing Melnikov functions of any order and using properties of Chebyshev systems, we prove that if [Formula: see text] is odd, then the maximum number of nontrivial limit cycles bifurcating from the periodic annulus of the unperturbed system is 6 and it is attainable, and if [Formula: see text] is even, then the maximum number is 3, and it can be attained too.
Noise-Induced Transformations in a System of Two Coupled Equilibrium and Chaotic Subpopulations
Authors: Belyaev Alexander , Bashkirtseva Irina , Ryashko Lev
Published: December 2022

We study the collective behavior of populations, coupling the equilibrium and chaotic subsystems by mutual migration. It is assumed that the dynamics of an isolated subsystem is modeled by the Ricker map, and the intensity of migrations within the metapopulation is subject to random perturbations. In the deterministic case, we specify parameter zones of mono- and birhythmicity with regular and chaotic attractors. Noise-induced multistage transitions from order to chaos and vice versa are investigated from an approach that combines direct numerical simulations, studies of chaotic transients, stochastic sensitivity, and confidence domains.
Investigation of Optical and Magnetic Properties of Nanostructured CdS- and Cr-Doped CdS Nanorods Dilute Magnetic Semiconductor
Authors: Ren Yinshuan , Zhang Zhufeng , Xie Guoya , Li Xuefeng
Published: December 2022

Two novel CdS- and Cr-doped CdS nanostructures, including nanoparticles and nanoparticles, were successfully synthesized by solvothermal reaction with hydrazine hydrate (HHA), ethylene glycol (EG), ethylenediamine (EN) and ethanolamine (EA) as mixed solvents in different sulfur and cadmium sources. The structure, morphology and properties of the products were characterized using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectrometer (EDS) and Vibrating sample magnetometer (VSM), respectively. The morphology of the Cr-doped CdS nanostructures was nanorod, with an average diameter of 70–90[Formula: see text]nm and lengths of 1–2.5[Formula: see text][Formula: see text]m. The product was observed to be composed of S, Cd and Cr by EDS. The VSM tests demonstrated that the Cr-doped CdS nanorods had super strong ferromagnetism at room temperature, while pure CdS nanorods were weak ferromagnetism. The results confirmed that the prepared the Cr-doped CdS nanorods had ferromagnetism at room temperature, and the saturation magnetization [Formula: see text] was approximately 9.125 (10[Formula: see text][Formula: see text]emu/g), the coercivity of [Formula: see text] was approximately 139.22[Formula: see text]Oe.
RoSGAS
: Adaptive Social Bot Detection with Reinforced Self-supervised GNN Architecture Search
Authors: Yang Yingguang , Yang Renyu , Li Yangyang , Cui Kai , Yang Zhiqin , Wang Yue , Xu Jie , Xie Haiyong
Published: December 2022

Social bots are referred to as the automated accounts on social networks that make attempts to behave like humans. While Graph Neural Networks (GNNs) have been massively applied to the field of social bot detection, a huge amount of domain expertise and prior knowledge is heavily engaged in the state-of-the-art approaches to design a dedicated neural network architecture for a specific classification task. Involving oversized nodes and network layers in the model design, however, usually causes the over-smoothing problem and the lack of embedding discrimination. In this article, we propose
RoSGAS
, a novel
R
einf
o
rced and
S
elf-supervised
G
NN
A
rchitecture
S
earch framework to adaptively pinpoint the most suitable multi-hop neighborhood and the number of layers in the GNN architecture. More specifically, we consider the social bot detection problem as a user-centric subgraph embedding and classification task. We exploit the heterogeneous information network to present the user connectivity by leveraging account metadata, relationships, behavioral features, and content features.
RoSGAS
uses a multi-agent deep reinforcement learning (RL), 31 pages. mechanism for navigating the search of optimal neighborhood and network layers to learn individually the subgraph embedding for each target user. A nearest neighbor mechanism is developed for accelerating the RL training process, and
RoSGAS
can learn more discriminative subgraph embedding with the aid of self-supervised learning. Experiments on five Twitter datasets show that
RoSGAS
outperforms the state-of-the-art approaches in terms of accuracy, training efficiency, and stability and has better generalization when handling unseen samples.
CDSM:

C

ascaded

D

eep

S

emantic

M

atching on Textual Graphs Leveraging Ad-hoc Neighbor Selection
Authors: Yao Jing , Liu Zheng , Yang Junhan , Dou Zhicheng , Xie Xing , Wen Ji-Rong
Published: December 2022

Deep semantic matching aims at discriminating the relationship between documents based on deep neural networks. In recent years, it becomes increasingly popular to organize documents with a graph structure, then leverage both the intrinsic document features and the extrinsic neighbor features to derive discrimination. Most of the existing works mainly care about how to utilize the presented neighbors, whereas limited effort is made to filter appropriate neighbors. We argue that the neighbor features could be highly noisy and partially useful. Thus, a lack of effective neighbor selection will not only incur a great deal of unnecessary computation cost but also restrict the matching accuracy severely.

In this work, we propose a novel framework,
C
ascaded
D
eep
S
emantic
M
atching (
CDSM
), for accurate and efficient semantic matching on textual graphs. CDSM is highlighted for its two-stage workflow. In the first stage, a lightweight CNN-based ad-hod neighbor selector is deployed to filter useful neighbors for the matching task with a small computation cost. We design both one-step and multi-step selection methods. In the second stage, a high-capacity graph-based matching network is employed to compute fine-grained relevance scores based on the well-selected neighbors. It is worth noting that CDSM is a generic framework which accommodates most of the mainstream graph-based semantic matching networks. The major challenge is how the selector can learn to discriminate the neighbors’ usefulness which has no explicit labels. To cope with this problem, we design a weak-supervision strategy for optimization, where we train the graph-based matching network at first and then the ad-hoc neighbor selector is learned on top of the annotations from the matching network. We conduct extensive experiments with three large-scale datasets, showing that CDSM notably improves the semantic matching accuracy and efficiency thanks to the selection of high-quality neighbors. The source code is released at https://github.com/jingjyyao/CDSM.
Review—Electrodes Derived From Conducting Polymers and their Composites for Catalytic Conversion of Carbon Dioxide
Authors: Ashassi-Sorkhabi Habib , Kazempour Amir , Moradi-Alavian Saleh , Asghari Elnaz , Vinodh Rajangam , Pollet Bruno G.
Published: December 2022

Conversion of carbon dioxide to value-added products (also termed as CO2 reduction reaction or CRR) is an exceptional route to diminish the CO2 amount in the atmosphere and meet the energy and global warming crisis. Within this framework, many types of research have been focused on introducing novel catalysts to reach an efficient system for the CRR. Conducting polymers (CPs) with appropriate electroactive characteristics have been used as effective catalysts for CRR for more than two decades. The polypyrrole (PPy) and polyaniline (PANI) are two of the most commonly studied CPs. Accordingly, this work presents a comprehensive review of the electrocatalytic performance of conducting polymers, including their composites, for CO2 reduction; a comparative approach is also followed to indicate their advantages and disadvantages over common metal-based heterogeneous electrocatalysts. The important perspectives and key challenges for developing these catalysts are also discussed.
Cathode Electrochemical Performance of PEMFCs with Compressed Gas Diffusion Layer: A Pore-Scale Investigation
Authors: Wang Hao , Yang Guogang , Su Fengmin , Li Shian , Shen Qiuwan , Liao Jiadong , Jiang Ziheng , Zhang Guoling , Li Zheng
Published: December 2022

Proton exchange membrane fuel cells (PEMFCs) are one of the most promising power sources in the fields of vehicle and ship power. Compression caused by assembly pressure, freeze-thaw cycles, and mechanical vibration can cause changes in the microstructure of the gas diffusion layer (GDL), thereby affecting the mass transfer and electrochemical reaction processes inside the PEMFC. In this paper, a three-dimensional single-phase multi-component lattice Boltzmann (LB) model is established to investigate the effects of binder volume fraction and compression on the cathode electrochemical performance. The stochastic reconstruction method is employed to generate 20 GDLs with different binder volume fractions and compression ratios. Afterward, the reactive gas flow within the 20 GDLs is simulated, and the distribution of oxygen mole fraction, water vapor mole fraction, and the current density are analyzed. The simulation results demonstrate that the mean current density decreases with the increase of the compression ratio, and the optimal binder volume fraction of 20% resulted in the highest current density. This paper enriches the research on the cathode electrochemical performance of PEMFCs at the pore scale and provides a guideline for optimizing the GDL design.
The Role of Oxygen in Lithiation and Solid Electrolyte Interphase Formation Processes in Silicon-Based Anodes
Authors: Li Zhifei , Stetson Caleb , Frisco Sarah , Harvey Steve , Huey Zoey , Teeter Glenn , Engtrakul Chaiwat , Burrell Anthony , Li Xiaolin , Zakutayev Andriy
Published: December 2022

Silicon oxides (SiOx) have been considered as promising alternatives to pure Si in high energy anodes in lithium-ion batteries (LIBs) due to their improved cycling stability. However, their fundamental lithiation mechanism has not yet been systematically investigated, and potential collateral downsides remain unclear. In this work, we report on the role of oxygen in lithiation/delithiation and solid electrolyte interphase (SEI) formation processes in SiOx thin film model electrodes with different oxygen contents. We show that the SiOx anodes with higher oxygen content experience smaller volume change and form a thinner and more stable SEI, both of which are beneficial for cycling stability. However, these SiOx anodes also show an irreversible lithiation at around 0.7 V attributed to the reduction of Si oxides, leading to lower first cycle coulombic efficiency that is undesirable for practical applications. Overall, these results offer a balanced perspective on the advantages and disadvantages that oxygen brings to Si-based anodes in LIBs.
Integrated Effect of Flow Field Misalignment and Gas Diffusion Layer Compression/Intrusion on High Temperature – Polymer Electrolyte Membrane Fuel Cell Performance
Authors: K. P. Venkatesh Babu , Varghese Geethu , Joseph Thadathil Varghese , Chippar Purushothama
Published: December 2022

Misalignment in the flow field plates of High-Temperature Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) due to manufacturing tolerances, assembly process, or unavoidable vibration during the cell operation is contemplated its performance and durability. This study investigates the effect of flow field plate misalignment and its concomitant impact with varying the clamping pressures on HT-PEMFC operation. The study considers six degrees of cathode flow field misalignment, varying from 0% to 100% with respect to the anode flow field. Clamping pressures ranging from 1 to 2 MPa are applied to the various cases of misalignment to study their effect on GDL deformation and intrusion into the channels. The structural analysis shows that as the misalignment increases from 0 to 100%, the GDL compression increases from 26.72% to 37.75% for 1 MPa, 40.07% to 56.63% for 1.5 MPa, and 53.43% to 75.51% for 2 MPa, owing to the increase in compression approximately by 41% from their base cases and it is also crucial to note that GDL compression exaggerates at higher clamping pressures. The misalignment results in the sagging of Membrane Electrode Assembly (MEA), and the amplitude of wave nature is proportional to the degree of misalignment and clamping pressure, indicating the misalignment is the sole factor for structural changes. As a result, considerable variance in current distribution and average value is observed, i.e., at operating voltage 0.5 V, the current density drops from 4472.7 to 4264.4, 4420.7 to 4211.8, and 4374.1 to 4161.3 A m−2 from cases 1 to 6 for clamping pressures 1, 1.5, and 2 MPa, respectively, resulting in a 4.7% loss in performance. According to the observations, a misalignment of 60% is tolerable, with minimal performance loss and negligible non-uniformity in cell distributions.
Dual-Amplifying Electrochemiluminescence Sensor Based on CdS QDs@HKUST-1/MWCNTs Composite for Sensitive Catechol Assay
Authors: Zhao Wenrui , Wang Beibei , Ji Xueping , Kang Kai , Wang Bing , Wang Lin , Ren Jujie
Published: December 2022

Herein, a novel electrochemiluminescence (ECL) sensor was developed using a dual signal amplification mechanism based on a typical HKUST-1 metal-organic framework, [Cu3(BTC)2(H2O)3, BTC=1,3,5-benzene tricarboxylate], CdS quantum dots (QDs) and multi-walled carbon nanotubes (MWCNTs) for ultrasensitive determination of catechol. HKUST-1 not only has a dispersion effect to carry more CdS QDs for enhancing stability, but also acts as effective catalyzer to accelerate the transformation of persulfate ion (S2O8
2−) for generating more sulfate radical anions (SO4
•−), therefore amplifying the signal of the ECL sensor. Meanwhile, the introduction of MWCNTs to the ECL process could promote the electron transfer rate and accelerate the kinetics of the electro-catalytic reaction attributing to its stronger conductivity, achieving dual-amplifying effect, which could obviously increase the sensitivity of the ECL sensor. The proposed sensor displayed a wide linear range of 1 × 10−7 − 1 × 10−3 M and a low detection limit of 3.8 × 10−8 M with excellent stability, high repeatability and outstanding anti-interference ability under the optimal conditions. Impressively, the sensor possessed commendable feedback when detecting catechol in real samples. Therefore, this research provided a new strategy combining the advantages of MOFs, QDs and MWCNTs materials for phenolic pollutants detection.
Carbon Nanomaterials - Poly(3-octylthiophene-2,5-diyl) – Hydrous Iridium Dioxide Triple Composite Materials as Superhydrophobic Layers for Ion-Selective Electrodes
Authors: Lenar Nikola , Piech Robert , Paczosa-Bator Beata
Published: December 2022

In this paper, we introduce the new triple composite material consisting of three significantly different materials: carbon nanomaterial (carbon nanotubes and carbon black), conducting polymer (poly(3-octylthiophene-2, 5-diyl) and metal oxide (hydrous iridium dioxide). Combining those three components enabled to obtain superhydrophobic materials (of contact angle value up to 180°). Both designed materials were characterized with high values of electrical capacitance parameters (1.5 and 0.9 mF) and low values of resistance (72.9 ± 0.3 kΩ and 23.5 ± 0.2 kΩ for NT-based and CB-based electrode, respectively). The new functional material was implemented into potassium-selective electrodes in order to improve their electrical and analytical parameters. This is the first presented so far potentiometric sensor with solid-contact layer composed of three significantly different materials. The superhydrophobic layer of triple composite material improved (in contrast to previous solutions) long-term stability (characterized by potential drift of 43 μV h−1 and 79 μV h−1 for the NT-based and CB-based electrode, respectively) and repeatability enabled limiting the number of necessary calibrations. Potentiometric sensors presented in the scope of this work enable potassium determination in the wide range of potassium ions (from 10−6 to 10−1 M of K+ ions). The possibility of practical application was successfully confirmed by the analysis of potassium in vegetable juices.
Fabrication and Analytical Investigation of Reduced Graphene Oxide and Poly-L-Glutathione Based Voltammetric Sensor for the Individual and Simultaneous Determination of Purine Derivative and Metabolites
Authors: Chandran Amoolya , Sam Sonia , Girish Kumar K.
Published: December 2022

Purine metabolites are considered as recognized disease biomarkers and food quality inspecting parameters. Hence, reliable electro-analytical strategies for the quantification of purine bases are indispensable in clinical point of view. This article proposes an efficient voltammetric sensor based on reduced graphene oxide and poly-L-Glutathione modified glassy carbon electrode (GCE) for the determination of purine bases such as Uric acid (UA), Xanthine (XA), Hypoxanthine (HX) and Theobromine (TB). Surface characterisation of GCE has been carried out via surface area determination, Scanning Electron Microscopy, Atomic Force Microscopy, Raman spectroscopy, Attenuated Total Reflection Spectroscopy, Cyclic Voltammetry and Electrochemical Impedance Spectroscopy. For the simultaneous determination, the sensor offers a limit of detection of 1.83 × 10−7 mol l−1, 6.70 × 10−8 mol l−1, 2.12 × 10−7 mol l−1 and 1.14 × 10−6 mol l−1 for UA, XA, HX and TB respectively. The practical utility of the sensor has been ascertained via analysis in real samples and the findings are validated using conventional analytical methods. Mechanistic aspects involved in the electrooxidation of analytes have been derived using scan rate studies. Wide concentration linear range with low limit of detection and successful applicability studies in tea, coffee, cocoa and artificial physiological samples point towards the efficacy of the analytical assay in real sample analysis.
A Review on Path Planning and Obstacle Avoidance Algorithms for Autonomous Mobile Robots
Authors: Rafai Anis Naema Atiyah , Adzhar Noraziah , Jaini Nor Izzati
Published: December 2022

Mobile robots have been widely used in various sectors in the last decade. A mobile robot could autonomously navigate in any environment, both static and dynamic. As a result, researchers in the robotics field have offered a variety of techniques. This paper reviews the mobile robot navigation approaches and obstacle avoidance used so far in various environmental conditions to recognize the improvement of path planning strategists. Taking into consideration commonly used classical approaches such as Dijkstra algorithm (DA), artificial potential field (APF), probabilistic road map (PRM), cell decomposition (CD), and meta-heuristic techniques such as fuzzy logic (FL), neutral network (NN), particle swarm optimization (PSO), genetic algorithm (GA), cuckoo search algorithm (CSO), and artificial bee colony (ABC). Classical approaches have limitations of trapping in local minima, failure to handle uncertainty, and many more. On the other hand, it is observed that heuristic approaches can solve most real-world problems and perform well after some modification and hybridization with classical techniques. As a result, many methods have been established worldwide for the path planning strategy for mobile robots. The most often utilized approaches, on the other hand, are offered below for further study.
Preparation of Copper Nanoparticles/Diatomite Nanocomposite for Improvement in Water Quality of Fishponds
Authors: Hanh Truong Thi , Lan Chi Nguyen Thuy , Duy Nguyen Ngoc
Published: December 2022

Diatomite (DA) with the main component of silica (SiO2) was chemically modified by amine groups of the coupling agent 3-amino propyl triethoxysilane (APTES) before deposition of Cu2+ ions. The mixture of DA-APTES and Cu2+ ions in the chitosan stabilizer (1%) was added with ascorbic acid and purged oxygen by N2O for antioxidation before irradiation. Cu2+ ions were reduced to Cu0 and aggregation into copper nanoparticles (CuNPs) on DA by an electron beam (EB). Characterizations of CuNPs onto DA were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), UV-Vis spectra, transmission electron micrography (TEM), Fourier transform infrared (FT-IR) spectra, and BET-specific surface area. A nanocomposite of CuNPs/DA with the porous structure of DA is capable of improving the water quality by adsorption of organic pollutants and suspended solids. Therefore, the values of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) decreased for samples of fishpond water after treatment with CuNPs/DA. Antibacterial activity of CuNPs/DA nanocomposite against pathogenous bacteria for catfish such as Aeromonas hydrophila and Edwardsiella ictaluri was estimated.
A Human Oral Fluid Assay for D- and L- Isomer Detection of Amphetamine and Methamphetamine Using Liquid-Liquid Extraction
Authors: Robbins Brian , Carpenter Rob E. , Long Mary , Perry Jacob
Published: December 2022

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water, diluted with mobile phase, with separation and detection accomplished using LC-MS/MS to determine analyte concentration. Once samples were confirmed positive for (meth)amphetamine from the large oral fluid assay, they were further examined for the enantiomeric forms with 50 μl aliquots of the standards and samples of interest combined with 450 μl of D- and L-assay mobile phase, then analyzed using chiral column separation, and LC-MS/MS detection with standard curve spanning the range from 2.5 to 1000 ng/mL. The result is a sensitive and accurate detection of D- and L-isomers of amphetamine and methamphetamine in human oral fluid performed on an older model mass spectrometer (AB SCIEX 4000). The novelty of this assay is twofold (a) the 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples, and (b) its adoption characteristics as a reflex test from a large ODT panel without the need to invest in newer or expensive LC-MS/MS instruments. Finally, this assay also has potential to add a valuable option to high-throughput laboratories seeking a D- and L-testing alternative to urine drug testing methods.
The Health Effects of 14 Weeks of Physical Activity in a Real-Life Setting for Adults with Intellectual Disabilities
Authors: Højberg Laurits Munk , Helge Eva Wulff , Pingel Jessica , Wienecke Jacob
Published: December 2022

Background. The life expectancy of individuals with intellectual disabilities (ID) is reduced compared to the general population, and one of the main contributors to earlier death is inactivity. Aim. To investigate how 14 weeks of physical activity (PA) in a real-life setting affects cardiovascular fitness, body composition and bone health of adults with ID. Methods. Adults with ID were recruited into a PA-group (N = 52) or a control group (CON, N = 14). The PA-group participated in 14 weeks of PA, and body composition, cardiovascular fitness and bone health were assessed before and after the intervention. Outcomes and Results. Cardiovascular fitness and body composition improved from pre to post within the PA-group: Heart rates (HR) during the last 30 seconds of two increments of a treadmill test, were reduced (3.2 km/h: −4.4 bpm,

p
<
0.05

; 4.8 km/h: −7.5 bpm,

p
<
0.001

) and fat mass was reduced (−1.02 kg,

p
<
0.05

). A between-group difference in favour of the PA-group, were observed in whole body bone mineral density (BMD) (0.024 g/cm2,

p
<
0.05

). Conclusions and Implications. Fourteen weeks of PA performed in a real-life setting increased cardiovascular fitness, reduced fat mass and improved BMD in the weight-bearing skeleton in the PA-group. Increased and regular PA seems to be a promising tool to promote physical health in adults with ID.
Peptide–Polymer Conjugates: A Promising Therapeutic Solution for Drug-Resistant Bacteria
Authors: Shen Xuqiu , Zhang Yiyin , Mao Qijiang , Huang Zhengze , Yan Tingting , Lin Tianyu , Chen Wenchao , Wang Yifan , Cai Xiujun , Liang Yuelong
Published: December 2022

By 2050, it is estimated that 10 million people will die of drug-resistant bacterial infection caused by antibiotic abuse. Antimicrobial peptide (AMP) is widely used to prevent such circumstances, for the positively charged AMPs can kill drug-resistant bacteria by destroying negatively charged bacterial cell membrane, and has excellent antibacterial efficiency and low drug resistance. However, due to the defects in low in vivo stability, easy degradation, and certain cytotoxicity, its practical clinical application is limited. The emergence of peptide–polymer conjugates (PPC) helps AMPs overcome these shortcomings. By combining with functional polymers, the positive charge of AMPs is partially shielded, and its stability and water solubility are improved, so as to prolong the in vivo circulation time of AMPs and reduce its cytotoxicity. At the same time, the self-assembly ability of PPC enables it to assemble into different nanostructures to undertake specific antibacterial tasks. At present, PPC is mainly used in wound dressing, bone tissue repair, antibacterial coating of medical devices, nerve repair, tumor treatment, and oral health maintenance. In this study, we summarize the structure, synthesis methods, and the clinical applications of PPC, so as to present the current challenges and discuss the future prospects of antibacterial therapeutic materials.
Species Composition, Structure, and Regeneration Status of Woody Plants and Anthropogenic Disturbances in Zijje Maryam Church Forest, Ethiopia
Authors: Mekonnen Amare B. , Wassie Wubetie A. , Ayalew Habtemaryam , Gebreegziabher Berhane G.
Published: December 2022

Our current study was conducted in Zijje Maryam Church Forest, Ethiopia, to explore woody species composition, structure, regeneration status, and anthropogenic disturbances inside the sacred groves. The aforementioned information for adequate conservation and management of the church forest is not well documented. Fifteen main quadrats each having an area of 625 m2 (25 m × 25 m) were used for vegetation and disturbance data collection. Determination of the sampled quadrats was based on the principle that minimum quadrats give the smallest possible area in which all species occurring in the church forest are present. All woody species with a diameter at breast height (DBH) ≥ 2.5 cm within the quadrat were identified, counted, and their height and DBH data were recorded. The criterion to start at DBH ≥ 2.5 cm was to exclude seedlings having DBH < 2.5 cm and height ≤0.6 m. Sapling and seedling data were collected using 45 saplings and 45 seedling quadrat that measured 4 m2 and 1 m2, respectively. Vegetation data analysis and ANOVA were used for statistical comparison. A total of 48 woody plant species belonging to 46 genera and 36 families were identified. Fabaceae was the dominant family containing 5 species followed by Rosaceae with 3 species. Total basal area of the church forest was 83.03 m2 ha−1. The density of seedlings, saplings, and matured woody species stem ha−1 were 15555, 3833, and 865, respectively. Talking these densities, the regeneration status of the forest was good. The Shannon diversity and evenness of woody plant species in the forest was high, 3.29 and 0.85, respectively. Juniperus procera 27.67 (9.22%) and Olea europaea were species with the highest IVI. Nearly, 22% of areas of the forest get disturbed and higher anthropogenic disturbances occurred near the edge of the forest. Gathering, clearing, and grazing are the major human disturbances that stakeholders need to tackle for conservation. Zijje Maryam Church Forest has heterogeneous species composition with varied seedlings and saplings. Therefore, local conservation policies recommended not only protect large forests, but also the small and valuable forests service to the needs of local people.