bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Investigation of a Variable-Shape Buoy Wave Energy Converter
Authors: Shabara Mohamed A. , Zou Shangyan , Abdelkhalik Ossama
Published: October 2021

A novel Variable-Shape Buoy Wave Energy Converter (VSB WEC) that aims at eliminating the requirement of reactive power is analyzed in this paper. Unlike conventional Fixed Shape Buoy Wave Energy Converters (FSB WECs), the VSB WEC allows continuous shape-changing (flexible) responses to ocean waves. The non-linear interaction between the device and waves is demonstrated to result in more power when using simple, low-cost damping control system. High fidelity numerical simulations are conducted to compare the performance of a VSB WEC to a conventional FSB WEC, of the same volume and mass, in terms of power conversion, maximum displacements, and velocities. A Computational Fluid Dynamics (CFD) based Numerical Wave Tank (CNWT), developed using ANSYS 2-way fluid-structure interaction (FSI) is used for simulations. The results show that the average power conversion is significantly increased when using the VSB WEC.
A Review of DNVGL-RP-F105 Fatigue Assessment Model or Why My Free Span Has Not Failed
Authors: Caruso Mário
Published: October 2021

The objective of a free span fatigue assessment is to provide a rational criterion to evaluate the long-term integrity of a free spanning pipeline, to which DNVGL-RP-F105 was developed. The Recommended Practice has a long history. Guideline 14, the foundation document to it, was released in 1998. The guidelines of the DNVGL-RP-F105 were gradually adopted by the industry for free spans analysis, and even API 1111 makes direct reference to it. Today, DNVGL-RP-F105 is the de facto Vortex Induced Vibration analysis guide for all applications where small number of bending driven modes are expected to be excited, overstepping its original purpose of free spanning pipelines and providing guidance when no other source exists.

With such a long history, it is easy to forget the basis for the Recommended Practice fatigue model and obtain results that do not match expectations. A prime example is when assessing a free span based on survey and the fatigue life capacity calculated following the Recommended Practice is much smaller than the actual exposure time. In this situation one may ask “why my free span has not failed?” and conclude that the Recommended Practice is either too over conservative or plainly wrong.

This paper reviews some key aspects of the DNVGL-RP-F105 fatigue model and explore their implication to fatigue design and assessment. And it hopes to clarify why your free span has not failed even when you expected it to.
Sloshing Effects on FLNG and LNGC Side-by-Side Offloading
Authors: Koo Bonjun , Auburtin Erwan , Kim Hyoungchul
Published: October 2021

A side-by-side moored offloading configuration has relatively stronger hydrodynamic and mechanical interactions compared to a tandem moored offloading configuration. For instance, due to the narrow gap between FLNG and LNG Carrier, the trapped water resonance induces higher relative motions between the FLNG and LNG Carrier. In addition, due to the partial filling conditions during the offloading operations, the sloshing loads excite ship motions which induce higher loading on the offloading arms. In this research, a time domain sloshing-ship motion coupling analysis module has been developed for analyzing interactions of the side-by-side moored multiple floating platforms. This paper presents the numerical modeling, the validation analysis results, and the sloshing-ship motion coupled effects on the side-by-side offloading analysis.
Numerical Ocean Wave-Basin (NOW): A Numerical Solution for FSRU Mooring Design Analysis
Authors: Kim Jang , Jang Hyunchul , Lim Ho-Joon , Lai Lawrence , Latifah Arnida , Auburtin Erwan , Tcherniguin Nicolas , Petrie Francois
Published: October 2021

A numerical solution is proposed for the design analysis of the mooring system of an FSRU in shallow water. Previously. such analysis relied on second-order diffraction theory with viscous damping empirically calibrated from physical model tests. However, both experimental and theoretical methods had to introduce uncertainties in the predicted mooring load because of their physical and theoretical limitations. A complicated procedure had to be introduced to derive design loads considering the uncertainties and limitations. The proposed numerical solutions are developed to minimize those uncertainties by introducing the state-of-the-art numerical tools to accurately model the flow field near the FSRU and the surrounding wave field. A CFD-based numerical wave basin, MrNWB, and a potential-based higher-order Boussinesq wave model, HAWASSI, are coupled together to simulate the near- and outer-field free-surface flows around the FSRU hull.

This paper describes the framework of the proposed numerical method, followed by preliminary verifications of the accuracy and effectiveness of the proposed solution. A benchmark model test of an FSRU moored in a shallow sloping beach is used to validate the generation of the low-frequency wave and the slow-drift motion of FSRU from CFD simulation. The numerical results show significant improvement in the low-frequency FSRU responses compared to the conventional theoretical methods.
Independent Design Verification of Deepwater SCRs for the Application in South China Sea
Authors: Yang Hu , Cheng Yongming , Xu Fanli , He Ning
Published: October 2021

Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low cost and good adaptability to floating platform’s motion. SCRs have been selected as the production and export riser solution for Lingshui 17-2 (termed LS17-2) field in South China Sea, which consists of a subsea production system, a deep-draft semi-submersible, and an export riser/pipeline. This paper investigates independent design verification of deepwater SCRs for the application in South China Sea.

This paper first introduces a SCR system for LS17-2 project. The field for this project is located in northern South China Sea, with water depth of 1220m to 1560m. This paper describes the design verification methodology, procedure, riser computer modelling, extreme challenges, findings, and technical discussions. The independent design verification includes riser sizing, adjacent riser interference, cathodic protection, dynamic strength analysis, Vortex-Induced Vibration (VIV) analysis, wave motion fatigue analysis, semi-submersible Vortex-Induced Motion (VIM) fatigue analysis, and riser installation. Sensitivity study was carried out to demonstrate the accuracy of the results and the robustness of the riser design.

SCR designs are extremely sensitive to environmental loading and the motion characteristics of a host platform. The independent design verification shows that the riser governing location of global performance is at the riser Touch Down Point (TDP) region. Compression forces in an SCR touchdown area can be caused by extreme or survival load cases. Among the fatigue damage sources, fatigue damage contributions are dominated by wave motion, VIM and VIV.

This paper finally summarizes the findings from the independent verification work. It concludes that the SCR system design for LS17-2 development meets the requirements of API 2RD design code.
Uncertainty in Collapse Strength Prediction of Sandwich Pipelines
Authors: Bhardwaj U. , Teixeira A. P. , Guedes Soares C.
Published: October 2021

This paper assesses the uncertainty in the collapse strength of sandwich pipelines under external pressure predicted by various strength models in three categories based on interlayer adhesion conditions. First, the validity of the strength models is verified by comparing their predictions with sandwich pipeline collapse test data and the corresponding model uncertainty factors are derived. Then, a parametric analysis of deterministic collapse strength predictions by models is conducted, illustrating insights of models’ behaviour for a wide range of design configurations. Furthermore, the uncertainty among different model predictions is perceived at different configurations of outer and inner pipes and core thicknesses. A case study of a realistic sandwich pipeline is developed, and probabilistic models are defined to basic design parameters. Uncertainty propagation of models’ predictions is assessed by the Monte Carlo simulation method. Finally, the strength model predictions of sandwich pipelines are compared to that of an equivalent single walled pipe.
Nonlinear Fourier Analysis for Shallow Water Waves
Authors: Osborne Alfred R.
Published: October 2021

I consider nonlinear wave motion in shallow water as governed by the KP equation plus perturbations. I have previously shown that broad band, multiply periodic solutions of the KP equation are governed by quasiperiodic Fourier series [Osborne, OMAE 2020]. In the present paper I give a new procedure for extending this analysis to the KP equation plus shallow water Hamiltonian perturbations. We therefore have the remarkable result that a complex class of nonlinear shallow water wave equations has solutions governed by quasiperiodic Fourier series that are a linear superposition of sine waves. Such a formulation is important because it was previously thought that solving nonlinear wave equations by a linear superposition principle was impossible. The construction of these linear superpositions in shallow water in an engineering context is the goal of this paper. Furthermore, I address the nonlinear Fourier analysis of experimental data described by shallow water physics. The wave fields dealt with here are fully two-dimensional and essentially consist of the linear superposition of generalized cnoidal waves, which nonlinearly interact with one another. This includes the class of soliton solutions and their associated Mach stems, both of which are important for engineering applications. The newly discovered phenomenon of “fossil breathers” is also characterized in the formulation. I also discuss the exact construction of Morison equation forces on cylindrical piles in terms of quasiperiodic Fourier series.
Suction Caissons as Multipod OWT Foundations in Clay: Investigation of Loading Rate Effects
Authors: Antoniou Maria , Kourkoulis Rallis , Gelagoti Fani , Anastasopoulos Ioannis
Published: October 2021

The paper elaborates on the bearing mechanics of suction caissons serving as the foundation system of offshore wind turbines (OWTs) supported on jacket structures. As axial loading governs foundation design in this configuration, the study proceeds to a numerical investigation of the tensile load carrying capacity of a suction caisson in clay through a series of coupled pore fluid diffusion — effective stress analyses with a hypoplastic constitutive model. The latter allows for the quantification of loading rate effects on the amount of negative excess pore pressures (passive suction) generated within the confined soil plug and their contribution to uplift caisson resistance. Based on these results, a simplified uncoupled procedure is employed to account for loading rate effects in the performance-based design of an 8MW OWT founded on a Suction Bucket Jacket (SBJ).
Investigation of Near-Field Temperature Distribution in Buried Dense Phase CO2 Pipelines
Authors: Olugunwa Babafemi , Race Julia , Yurtseven Ahmet , Tezdogan Tahsin
Published: October 2021

Buried pipelines transporting dense phase Carbon dioxide CO2 are crucial to carbon reduction and climate change mitigating technologies such as Carbon Capture and Storage (CCS) and Carbon Capture Utilization and Storage (CCUS). One of the major challenges for optimum pipeline operating conditions is to avoid phase change of the compressed CO2 and maintain temperature and pressure above the critical point throughout the pipeline route. A suitable pipe-soil heat transfer model during design can mitigate this challenge. However, variations in annual ambient temperatures, ground temperature at pipeline burial depth and soil temperature profile behaviors with seasonal climatic conditions especially during winter and summer periods also affect the heat transfer process between the soil burial medium and the CO2 pipeline. Assuming steady state, this paper investigates the nearfield temperature distribution up to 3m lateral distance away from a buried dense phase CO2 pipeline by numerical simulation with a two-dimensional pipe-soil heat transfer model at a burial depth of 2.3m to pipe center using a finite volume computational code. Results show that thermal parameters such as thermal conductivity and the soil temperature profile influence the heat exchange between pipe walls and porous soil medium. Consequently, this study shows that the near-field temperature distribution and effect of heat around a buried CO2 pipeline diminishes with distance and burial depth further away within the immediate vicinity of the pipeline.
Software-in-the-Loop Combined Machine Learning for Dynamic Responses Analysis of Floating Offshore Wind Turbines
Authors: Chen Peng , Hu Changhong , Hu Zhiqiang
Published: October 2021

Artificial intelligence (AI) brings a new solution to overcome the challenges of Floating offshore wind turbines (FOWTs) to better predict the dynamic responses with intelligent strategies. A new AI-based software-in-the-loop method, named SADA is introduced in this paper for the prediction of dynamic responses of FOWTs, which is proposed based on an in-house programme DARwind. DARwind is a coupled aero-hydro-servo-elastic in-house program for FOWTs, and a reinforcement learning method with exhaust algorithm and deep deterministic policy gradient (DDPG) are embedded in DARwind as an AI module. Firstly, the methodology is introduced with the selection of Key Disciplinary Parameters (KDPs). Secondly, Brute-force Method and DDPG algorithms are adopted to changes the KDPs’ values according to the feedback of 6DOF motions of Hywind Spar-type platform through comparing the DARwind simulation results and those of basin experimental data. Therefore, many other dynamic responses that cannot be measured in basin experiment can be predicted in good accuracy with SADA method. Finally, the case study of SADA method was conducted and the results demonstrated that the mean values of the platform’s motions can be predicted with higher accuracy. This proposed SADA method takes advantage of numerical-experimental method, basin experimental data and the machine learning technology, which brings a new and promising solution for overcoming the handicap impeding direct use of conventional basin experimental way to analyze FOWT’s dynamic responses during the design phase.
Experimental Study of Combined Wave and Ice Loads on a Fixed Offshore Structure
Authors: Mintu Shafiul , Molyneux David
Published: October 2021

Ice floes in the marginal ice zone (MIZ) are exposed to wind, wave, and current forces which greatly influence the dynamics of the ice floes. ISO 19906 recommends considering combined wave and ice actions while designing offshore structures for arctic and cold regions. Few studies have focused on ice-structure interactions in waves. There are not many tools available to estimate these combined loads on structures. A numerical tool “SAMICE” has been developed to simulate the hydrodynamics of wave-ice interactions, but there exists a lack of data for a realistic MIZ under wave actions for validation studies of the numerical code.

To address this gap and to investigate the hydrodynamics of ice floes under waves, a set of experiments was conducted at the wave tank of Ocean Engineering Research Center (OERC) of Memorial University of Newfoundland. A six-component dynamometer was used to measure the loads on a model scale aluminum cylindrical gravity-based offshore structure. Loads were measured for five regular waves of various steepness in combination with three current speeds. Two ice concentrations with various floe sizes of random shapes were prepared from polypropylene sheets to represent the MIZ. Most of the tests were repeated three times and a statistical approach was used to analyze the loads. The preliminary analysis shows that the average wave-ice loads may be determined by ISO guidelines, but the predictions of impulse loads from individual wave-driven ice floes are very uncertain.
Numerical Investigation on Vortex Induced Motions of a Tension Leg Platform With Circular Columns
Authors: Zhi Pengfei , Zhang Xinshu
Published: October 2021

Vortex Induced Motion (VIM) of multi-column floating platforms, such as Tension Leg Platform (TLP) and semi-submersible (SEMI), in current is well-acknowledged. Substantial VIM response of the multi-column floating platform may cause fatigue failure of mooring and riser systems, which can affect the normal operation of the platform.

The present paper focuses on the numerical investigation on VIM of a TLP with circular columns using Computational Fluid Dynamics (CFD). Sensitivity analyses (e.g., mesh size, the number of prism layers and time-step size) for the VIM responses of the TLP are conducted. The effects of the current heading and mooring stiffness on the VIM are investigated. The three degrees of freedom VIM responses (in-line, transverse and yaw responses) and corresponding amplitude spectra are computed and analyzed. Motion trajectories are plotted to understand the VIM behaviors. Regarding the effect of the current heading, the largest transverse response is examined at 15° current heading and the corresponding maximum nominal amplitude is around 0.43. The difference of the maximum nominal amplitudes between the cases at 0° and 15° current headings is less than 5%. For 15°, 30° and 45° current headings, the nominal transverse amplitudes decrease as the current heading increases in the lock-in range. For the four studied current headings, the maximum width of the lock-in range is found at 0° current heading and narrows as the current incidence increases. The largest yaw response is observed at 0° current heading and the maximum nominal amplitude is around 9.1°. Regarding the effect of the mooring stiffness, the lock-in ranges and the maximum nominal amplitudes of the transverse motions have little difference for the four mooring stiffnesses. The maximum nominal transverse and yaw responses are around 0.25 and 5.1°, respectively, which occur when the mooring stiffness reaches the maximum. The flow pattern analyses indicate that the flow interference between the upstream and downstream columns may have significant effects on the VIM responses and a stronger interference at the present spacing ratio may lead to a larger VIM response. The contours of the vertical vorticity in the horizontal plane show that the mean positions of the flow separation points are always on highest or lowest (in the transverse direction perpendicular to the current heading) points of the columns, which is the reason that the VIM trajectories for the TLP with circular columns are always along the direction perpendicular to the current heading.
Webinar | Deciphering cancer: The intersection of epigenetics, metabolism, and tumorigenesis
Authors: Wellen Kathryn , Locasale Jason
Published: October 2021

Epigenetic modifications to DNA and histone proteins are known to regulate metabolic gene expression, which in turn impacts metabolite levels. Conversely, the machinery responsible for modifying DNA and histones at the epigenetic level is highly sensitive to metabolites arising from cellular metabolism. Thus, the metabolic changes associated with oncogenesis may affect the epigenetic machinery, creating a feedback loop that synergistically promotes the progression of cancer. This webinar will examine how, by targeting proteins responsible for the crosstalk between epigenetics and metabolism, we may be able to develop new and effective therapeutic options for cancer treatment.

View the Webinar
U.K. scientists gird for future break with EU
Authors: Stokstad Erik
Published: October 2021

Government largesse may ease Brexit—at least for applied science.
How plants learned to breathe
Authors: Pennisi Elizabeth
Published: October 2021

Even early plants likely had sophisticated pores to regulate water and swap gases with their environment.
Unearthing democracy's roots
Authors: Wade Lizzie
Published: October 2021

In some ancient Mesoamerican societies, rulers shared power and ordinary people had a voice.
New Insights into the Mechanism of Action of the Cyclopalladated Complex (CP2) inLeishmania: Calcium Dysregulation, Mitochondrial Dysfunction, and Cell Death
Authors: Velásquez Angela M. A. , Bartlett Paula J. , Linares Irwin A. P. , Passalacqua Thais G. , Teodoro Daphne D. L. , Imamura Kely B. , Virgilio Stela , Tosi Luiz R. O. , Leite Aline de Lima , Buzalaf Marilia A. R. , Velasques Jecika M. , Netto Adelino V. G. , Thomas Andrew P. , Graminha Marcia A. S.
Published: October 2021

The current treatment of leishmaniasis is based on a few drugs that present several drawbacks, such as high toxicity, difficult administration route, and low efficacy. These disadvantages raise the necessity to develop novel antileishmanial compounds allied with a comprehensive understanding of their mechanisms of action.
Acute Kidney Injury Associated with Area under the Curve versus Trough Monitoring of Vancomycin in Obese Patients
Authors: D’Amico Heather , Wallace Katie L. , Burgess Donna , Burgess David S. , Cotner Sarah , Mynatt Ryan , Li Nannan , Stromberg Arnold , VanHoose Jeremy
Published: October 2021

Vancomycin is a first-line agent used in the treatment of methicillin-resistant
Staphylococcus aureus
; however, vancomycin is associated with acute kidney injury (AKI). Previous literature demonstrates decreased incidence of AKI using 24-h area under the concentration-time curve (AUC
24
) monitoring, but its safety is unknown in obese populations.
Population Pharmacokinetics of Vancomycin in Critically Ill Adult Patients Receiving Extracorporeal Membrane Oxygenation (an ASAP ECMO Study)
Authors: Cheng Vesa , Abdul-Aziz Mohd H. , Burrows Fay , Buscher Hergen , Cho Young-Jae , Corley Amanda , Diehl Arne , Gilder Eileen , Jakob Stephan M. , Kim Hyung-Sook , Levkovich Bianca J. , Lim Sung Yoon , McGuinness Shay , Parke Rachael , Pellegrino Vincent , Que Yok-Ai , Reynolds Claire , Rudham Sam , Wallis Steven C. , Welch Susan A. , Zacharias David , Fraser John F. , Shekar Kiran , Roberts Jason A.
Published: October 2021

Our study aimed to describe the population pharmacokinetics (PK) of vancomycin in critically ill patients receiving extracorporeal membrane oxygenation (ECMO), including those receiving concomitant renal replacement therapy (RRT). Dosing simulations were used to recommend maximally effective and safe dosing regimens.
Evaluating Metabolic Pathways and Biofilm Formation in Stenotrophomonas maltophilia
Authors: Isom Cierra M. , Fort Blake , Anderson Gregory G.
Published: October 2021

Stenotrophomonas maltophiliais a prominent opportunistic pathogen that often forms biofilms during infection. However, the molecular mechanisms of virulence and biofilm formation are poorly understood.
Distinct Regions of the Haloferax volcanii Dolichol Phosphate-Mannose Synthase AglD Mediate the Assembly and Subsequent Processing of the Lipid-Linked Mannose
Authors: Zaretsky Marianna , Guan Ziqiang , Zarivach Raz , Eichler Jerry
Published: October 2021

In the archaeon
Haloferax volcanii
, the dolichol phosphate (DolP)-mannose synthase AglD charges the lipid DolP with mannose, which is delivered to a protein-bound tetrasaccharide to generate the pentasaccharide decorating glycoproteins in this organism. Structural studies demonstrated the similarity of AglD to
Pyrococcus furiosus
PF0058, the only archaeal DolP-mannose synthase with a solved three-dimensional structure.
Economic evaluation of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) for stroke prevention in patients with atrial fibrillation: a systematic review and meta-analysis
Authors: Noviyani Rini , Youngkong Sitaporn , Nathisuwan Surakit , Bagepally Bhavani Shankara , Chaikledkaew Usa , Chaiyakunapruk Nathorn , McKay Gareth , Sritara Piyamitr , Attia John , Thakkinstian Ammarin
Published: October 2021

Objectives

To assess cost-effectiveness of direct oral anticoagulants (DOACs) compared with vitamin K antagonists (VKAs) for stroke prevention in atrial fibrillation (AF) by pooling incremental net benefits (INBs).

Design

Systematic review and meta-analysis.

Setting

We searched PubMed, Scopus and Centre for Evaluation of Value and Risks in Health Registry from inception to December 2019.

Participants

Patients with AF.

Main outcome measures

The INB was defined as a difference of incremental effectiveness multiplied by willing to pay threshold minus the incremental cost; a positive INB indicated favour treatment. These INBs were pooled (stratified by level of country income, perspective, time-horizon, model types) with a random-effects model if heterogeneity existed, otherwise a fixed effects model was applied. Heterogeneity was assessed using Q test and I2statistic. Risk of bias was assessed using the economic evaluations bias (ECOBIAS) checklist.

Results

A total of 100 eligible economic evaluation studies (224 comparisons) were included. For high-income countries (HICs) from a third-party payer (TPP) perspective, the pooled INBs for DOAC versus VKA pairs were significantly cost-effective with INBs (95% CI) of $6632 ($2961.67 to $10 303.72; I2=59.9%), $6353.24 ($4076.03 to $8630.45; I2=0%), $7664.58 ($2979.79 to $12 349.37; I2=0%) and $8573.07 ($1877.05 to $15 269.09; I2=0%) for dabigatran, apixaban, rivaroxaban and edoxaban relative to VKA, respectively but only dabigatran was significantly cost-effective from societal perspective (SP) with an INB of $11 746.96 ($2429.34 to $21 064.59; I2=52.4%). The pooled INBs of all comparisons for upper-middle income countries (UMICs) were not significantly cost-effective. The ECOBIAS checklist indicated that risk of bias was mostly low for most items with the exception of five items which should be less influenced on pooling INBs.

Conclusions

Our meta-analysis provides comprehensive economic evidence that allows policy makers to generalise cost-effectiveness data to their local context. All DOACs may be cost-effective compared with VKA in HICs with TPP perspective. The pooling results produced moderate to high heterogeneity particularly in UMICs. Further studies are required to inform UMICs with SP.

PROSPERO registeration number

CRD 42019146610.
The impact of the COVID-19 pandemic on hospital utilisation in Sierra Leone
Authors: Sevalie Stephen , Youkee Daniel , van Duinen A J , Bailey Emma , Bangura Thaimu , Mangipudi Sowmya , Mansaray Esther , Odland Maria Lisa , Parmar Divya , Samura Sorie , van Delft Diede , Wurie Haja , Davies Justine I , Bolkan H A , Leather Andrew J M
Published: October 2021

Introduction

The COVID-19 pandemic has adversely affected health systems in many countries, but little is known about effects on health systems in sub-Saharan Africa. This study examines the effects of COVID-19 on hospital utilisation in a sub-Saharan country, Sierra Leone.

Methods

Mixed-methods study using longitudinal nationwide hospital data (admissions, operations, deliveries and referrals) and qualitative interviews with healthcare workers and patients. Hospital data were compared across quarters (Q) in 2020, with day 1 of Q2 representing the start of the pandemic in Sierra Leone. Admissions are reported in total and disaggregated by sex, service (surgical, medical, maternity and paediatric) and hospital type (government or private non-profit). Referrals in 2020 were compared with 2019 to assess whether any changes were the result of seasonality. Comparisons were performed using Student’s t-test. Qualitative data were analysed using thematic analysis.

Results

From Q1 to Q2, weekly mean hospital admissions decreased by 14.7% (p=0.005). Larger decreases were seen in male 18.8% than female 12.5% admissions. The largest decreases were in surgical admissions, a 49.8% decrease (p<0.001) and medical admissions, a 28.7% decrease (p=0.002). Paediatric and maternity admissions did not significantly change. Total operations decreased by 13.9% (p<0.001), while caesarean sections and facility-based deliveries showed significant increases: 12.7% (p=0.014) and 7.5% (p=0.03), respectively. In Q3, total admissions remained 13.2% lower (p<0.001) than Q1. Mean weekly referrals were lower in Q2 and Q3 of 2020 compared with 2019, suggesting findings were unlikely to be seasonal. Qualitative analysis identified both supply-side factors, prioritisation of essential services, introduction of COVID-19 services and pausing elective care, and demand-side factors, fear of nosocomial infection and financial hardship.

Conclusion

The study demonstrated a decrease in hospital utilisation during COVID-19, the decrease is less than reported in other countries during COVID-19 and less than reported during the Ebola epidemic.
Mental health symptoms in electronic football players
Authors: Pereira Ana Monteiro , Teques Pedro , Verhagen Evert , Gouttebarge Vincent , Figueiredo Pedro , Brito João
Published: October 2021

Background

The escalated competitive pressure and professionalisation of esports players could predispose them to mental health symptoms. We aimed to develop a model to explore the association between distress and anxiety/depression symptoms and potential associations between adaptive or maladaptive coping strategies, sleeping disturbance, alcohol consumption and eating habits in electronic football players.

Methods

The present exploratory cross-sectional study includes the Distress Screener, General Health Questionnaire, Brief Cope, Sleep Disturbance Domain of the Patient-Reported Outcomes Measurement Information System, Alcohol Use Disorders Identification Test Consumption and a set of questions regarding eating habits. A two-step robust maximum likelihood method of the Structural Equation Modelling approach was used.

Results

Both measurement model (χ2/df=1065.04 (637), p<0.001; Tucker-Lewis Index (TLI)=0.91, Comparative Fit Index (CFI)=0.92, standardised root mean residual (SRMR)=0.07 and root mean square error of approximation (RMSEA)=0.05; 95% CI 0.043 to 0.053) and hypothesised structural model (χ2/df=1131.98 (648); p<0.001; TLI=0.90, CFI=0.91, SRMR=0.07 and RMSEA=0.05; 95% CI 0.054 to 0.06) showed an adequate fit to the data. Stress was positively related with depression and anxiety symptoms. Only anxiety symptoms were linked with coping strategies. Maladaptive coping strategies were related to sleep disturbance, alcohol consumption and poor eating habits, whereas adaptive coping strategies were associated with less sleep disturbance, reduced alcohol consumption and better eating habits.

Conclusion

An integrative approach to help electronic football players when early signs of distress are present might help avoid other mental health symptoms that interfere with players’ well-being and overall health. Additionally, adequate coping strategies to manage anxiety symptoms due to distress may help counteract potential negative consequences for lifestyle habits in electronic football players.
Aberrant expression ofBDNFmight serve as a candidate target for cocaine-induced psychosis: insights from bioinformatics analysis and microarray validation
Authors: Zhu Youwei , Zhao Yan , Xu Xiaomin , Su Hang , Li Xiaotong , Zhong Na , Jiang Haifeng , Du Jiang , Zhao Min
Published: October 2021

Background

Cocaine use disorder (CUD) and associated psychosis are major public health issues worldwide, along with high relapse outcome and limited treatment options. Exploring the molecular mechanisms underlying cocaine-induced psychosis (CIP) could supply integrated insights for understanding the pathogenic mechanism and potential novel therapeutic targets.

Aims

The aim of the study was to explore common alterations of CUD-schizophrenia-target genes and identify core risk genes contributing to CIP through data mining and network pharmacology approach.

Methods

Target genes of CUD were obtained from GeneCards, Comparative Toxicogenomics Database, Swiss Target Prediction platform and PubChem. Schizophrenia-related target genes were derived from DisGeNET, GeneCards, MalaCards and Online Mendelian Inheritance in Man databases. Then, the overlap genes of these two sets were regarded as risk genes contributing to CIP. Based on these CUD-schizophrenia-target genes, functional annotation and pathway analysis were performed using the clusterProfiler package in R. Protein–protein interaction network construction and module detection were performed based on the Search Tool for the Retrieval of Interacting Genes (STRING) database and Cytoscape software. Gene expression datasets GSE54839 and GSE93577 were applied for data validation and diagnostic capacity evaluation of interested hub genes.

Results

A total of 165 CUD-schizophrenia-target genes were obtained. These genes were mainly contributing to chemical synaptic transmission, neuropeptide hormone activity, postsynaptic membrane and neuroactive ligand–receptor interaction pathway. Network analysis and validation analysis indicated thatBDNFmight serve as an important risk gene in mediating CIP.

Conclusions

This study generates a holistic view of CIP and provides a basis for the identification of potential CUD-schizophrenia-target genes involved in the development of CIP. The abnormal expression ofBDNFwould be a candidate therapeutic target underlying the pathogenesis of CUD and associated CIP.
Interleukin 6 trans-signalling and the risk of future cardiovascular events in men and women
Authors: Miri Yasmin , Leander Karin , Eriksson Per , Gigante Bruna , Ziegler Louise
Published: October 2021

Objective

Pro-inflammatory interleukin 6 (IL6) trans-signalling is associated with increased risk of cardiovascular events (CVEs). Whether this association exists for both sexes is, however, uncertain. Hence, we analysed the risk of CVE associated with IL6 trans-signalling in men and women and investigated if potential interaction between IL6 trans-signalling and sex affects the risk.

Methods

In a prospective cohort of 60-year-old men and women without cardiovascular disease (men=2039, women=2193), subjects were followed for 20 years. To assess the IL6 trans-signalling activity, the proportion between the active binary and inactive ternary IL6 complexes, the binary/ternary ratio (B/T ratio), was estimated. CVE (myocardial infarction, angina pectoris and ischaemic stroke, n=629) risk was analysed with Cox regression, presented as HRs with 95% CIs. B/T ratio was dichotomised, with levels >median representing IL6 trans-signalling. Interaction was analysed on the additive scale and expressed as the synergy index (S). Analyses were adjusted for cardiovascular risk factors.

Results

B/T ratio >median was associated with increased CVE risk in men (HR 1.63; 95% CI 1.32 to 2.01), but not in women (HR 1.21; 95% CI 0.93 to 1.57). There was a significant synergistic interaction (S=1.98; 95% CI 1.15 to 3.42) between the B/T ratio and male sex, the combination increasing the risk by 88%.

Conclusions

Our results suggest differential susceptibility to inflammation mediated by IL6 trans-signalling and subsequent CVE in men and women. The B/T ratio could be considered as a novel biomarker for cardiovascular risk in men, but not in women.
Evaluation of low gradient severe aortic stenosis: should we change our outlook in the analysis of clinical data?
Authors: Corazza Ivan , Zecchi Margherita , Zannoli Romano
Published: October 2021

Nowadays, technological progress has equipped clinicians with new useful devices for the collection, analysis and presentation of data. As a consequence, many diseases and pathological conditions have been studied in a more detailed way, sometimes with remarkable results. In fact, they are not always validated by the old physiological models. In this respect, we present the case of low gradient severe aortic stenosis, a condition characterised by a small aortic valve area and a low-pressure gradient. According to the mathematical and physical assumptions these readings are contradictory whereas the Doppler-echocardiography shows clearly the existence of such a situation. In this work, we have described the physiological base of this phenomenon and discussed the limitations of the technology used. In this work, we are going to analyse some conditions commonly observed in daily clinical practice in order to prompt a critical outlook in both clinicians and technicians about the instrumentations used and the methods applied.
Barriers and facilitators to answering clinical questions in the Americas: a cross-sectional study of surgical trauma care providers
Authors: Noble Helen Elizabeth , Vega Rivera Felipe , LaGrone Lacey
Published: October 2021

Background

We aimed to understand how surgical trauma providers in the Americas acquire answers to clinical questions and what barriers and facilitators they face in efforts to practice according to recommendations for common surgical cases. We hypothesized that increased English proficiency and country income improved providers’ acquisition and application of clinical knowledge.

Methods

A 23-question survey evaluated reported confidence in interpretation of evidence, perceived language fluency, and access to and application of recommendations on sepsis and appendicitis. Electronic surveys were distributed across the Americas to Pan American Trauma Society members.

Results

108 participants from 21 countries completed this survey. 59% had ≥21 years of provider experience. 38% reported their English reading comprehension as less than or equal to “limited working proficiency.” 44% endorsed using Google Translate; 35% reported they did not need translation tools to evaluate medical literature. 59% felt uncertainty regarding clinical care at least weekly. 65% reported inability to answer their clinical questions at least once per month. 86% felt confident in their ability to interpret and apply evidence for their practice. To answer clinical questions, participants listed guidelines (76%), full-text peer-reviewed journal articles (61%), and meta-analyses (49%) as their most used resources. 25% answered all five clinical questions correctly, whereas 43% answered three or fewer correctly. 79% felt they had adequate access to resources to answer the five clinical questions. When controlling for individual demographic characteristics, decreased age (p<0.01) and increased country income level (p=0.03) positively impacted correct answers to questions.

Discussion

Uncertainties in clinical care are unavoidable. Language, age, and country income level impacted provider acquisition and application of knowledge relevant to select clinical scenarios. These findings highlight disparities in access and training and add urgency to the movement for improved dissemination and implementation approaches for evidence-based practice in surgery.

Level of evidence

IV.
Biquandle brackets and knotoids
Authors: Gügümcü Neslihan , Nelson Sam , Oyamaguchi Natsumi
Published: October 2021

Biquandle brackets are a type of quantum enhancement of the biquandle counting invariant for oriented knots and links, defined by a set of skein relations with coefficients which are functions of biquandle colors at a crossing. In this paper, we use biquandle brackets to enhance the biquandle counting matrix invariant defined by the first two authors in (N. Gügümcü and S. Nelson, Biquandle coloring invariants of knotoids, J. Knot Theory Ramif. 28(4) (2019) 1950029). We provide examples to illustrate the method of calculation and to show that the new invariants are stronger than the previous ones. As an application we show that the trace of the biquandle bracket matrix is an invariant of the virtual closure of a knotoid.
A class of locally indicable LOT groups
Authors: Cerdeiro Manuela Ana
Published: October 2021

This paper is concerned with the problem of asphericity of 2-complexes associated to labeled oriented trees (LOTs), which are combinatorial models of ribbon disc complements. The concept of good enumeration for LOTs is introduced and applied to the study of asphericity and local indicability. We describe a large class of LOTs, which includes some families of non-injective LOTs of any diameter and complexity, that present locally indicable groups.
A NEW TECHNIQUE FOR APPROXIMATE SOLUTION OF FRACTIONAL-ORDER PARTIAL DIFFERENTIAL EQUATIONS
Authors: ZADA LAIQ , NAWAZ RASHID , ALQUDAH MOHAMMAD A. , NISAR KOTTAKKARAN SOOPPY
Published: October 2021

In the present paper, the optimal auxiliary function method (OAFM) has been extended for the first time to fractional-order partial differential equations (FPDEs) with convergence analysis. To find the accuracy of the OAFM, we consider the fractional-order KDV-Burger and fifth-order Sawada–Kotera equations as a test example. The proposed technique has auxiliary functions and convergence control parameters, which accelerate the convergence of the method. The other advantage of this method is that there is no need for a small or large parameter assumption, and it gives an approximate solution after only one iteration. Further, the obtained results have been compared with the exact solution through different graphs and tables, which shows that the proposed method is very effective and easy to implement for different FPDEs.
ELECTROLYTIC EFFECT ON GROWTH OF GRAPHENE QUANTUM DOTS VIA ELECTROCHEMICAL PROCESS
Authors: PANYATHIP RANGSAN , SINTIAM THANAKRIT , WEERAPONG SORAWIT , NGAMJARUROJANA ATHIPONG , KUMNORKAEW PISIST , CHOOPUN SUPAB , SUCHARITAKUL SUKRIT
Published: October 2021

Quantum dots (QDs) are materials grown in confined dimension also known as 0D materials. QDs can be synthesized in many shapes and forms through various methods making the materials extremely versatile and can be fine-tuned for appropriate applications. Among the potentially scalable methods, Electrochemical process is considered as one of the top-down approaches with the highest potential for scalability and easy-to-process methodology while electrolyte and pH level can play various important roles on the final product. In this work, we grew and studied the effect of electrolytic solution in the growth of graphene quantum dots (GQDs) in colloidal forms using cheap graphite as precursor in KCl and NaOH as electrolytes in various concentrations. It can be inferred from our results that when KCl and NaOH were used in combination with citric acid, the optoelectrical properties and hydrodynamic properties of the resulting growth can be fine-tuned to match the required applications. [Formula: see text] electronics excitation was identified with small tunability of 487–500[Formula: see text]nm wavelength while the hydrodynamic size varied from 80–140[Formula: see text]nm with resulting pH range from 3.0–9.5 adjustable to appropriate applications, while the TEM results showed physical particle size of 1.7–3.7[Formula: see text]nm.
The square of Nijenhuis tensor and its vanishing results
Authors: Ling Jun
Published: October 2021

We give the strong form and the weak form of the square of Nijenhuis tensor, and some vanish results of the square.
On generalized adjacency Estrada index of graphs
Authors: Baghipur Maryam , Ramane Harishchandra S.
Published: October 2021

The Estrada index is a graph-spectrum-based invariant having an important role in chemistry and physics. In this paper, we define the generalized adjacency Estrada index of a graph and obtain some lower and upper bounds for the generalized adjacency Estrada index in terms of various graph parameters associated with the structure of a graph. Further, we characterize the extremal graphs attaining these bounds. We also highlight the relationship between generalized adjacency Estrada index and generalized adjacency energy. Using these results, we obtain the improved bounds for the Estrada index based on the adjacency eigenvalues of a graph.
Network Pharmacology‐Based and Molecular Docking‐Based Analysis of Suanzaoren Decoction for the Treatment of Parkinson’s Disease with Sleep Disorder
Authors: Liu Yan-yun , Yu Li-hua , Zhang Juan , Xie Dao-jun , Zhang Xin-xiang , Yu Jia-ming
Published: October 2021

This study is aimed at exploring the possible mechanism of action of the Suanzaoren decoction (SZRD) in the treatment of Parkinson’s disease with sleep disorder (PDSD) based on network pharmacology and molecular docking. Traditional Chinese Medicine Systems Pharmacology (TCMSP) was used to screen the bioactive components and targets of SZRD, and their targets were standardized using the UniProt platform. The disease targets of “Parkinson’s disease (PD)” and “Sleep disorder (SD)” were collected by OMIM, GeneCards, and DisGeNET databases. Thereafter, the protein‐protein interaction (PPI) network was constructed using the STRING platform and visualized by Cytoscape (3.7.2) software. Then, the DAVID platform was used to analyze the Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Cytoscape (3.7.2) software was also used to construct the network of the “herb‐component‐target‐pathway.” The core active ingredients and core action targets of the drug were verified by molecular docking using AutoDock software. A total of 135 Chinese herbal components and 41 corresponding targets were predicted for the treatment of PDSD using SZRD. Fifteen important signaling pathways were screened, such as the cancer pathway, TNF signaling pathway, PI3K‐AKT signaling pathway, HIF‐1 signaling pathway, and Toll‐like receptor signaling pathway. The results of molecular docking showed that the main active compounds could bind to the representative targets and exhibit good affinity. This study revealed that SZRD has the characteristics and advantages of “multicomponent, multitarget, and multipathway” in the treatment of PDSD; among these, the combination of the main active components of quercetin and kaempferol with the key targets of AKT1, IL6, MAPK1, TP53, and VEGFA may be one of the important mechanisms. This study provides a theoretical basis for further study of the material basis and molecular mechanism of SZRD in the treatment of PDSD.
Evolution of China’s Interprovincial Water Flow Network
Authors: Huang Taozhen , Li Yan , Zhang Qiaoliang
Published: October 2021

Traditionally, water governance focuses on water only. The emergence of virtual water breaks this limitation and integrates economic and social systems with the water resource system. This paper establishes an interprovincial complex network of virtual water flows in China, based on the theory on complex network, which has rarely been adopted to study the virtual water transfer network. Then, the authors analyzed the pattern and evolutionary features of China’s interprovincial virtual water flow network. In this way, the complex network theory was successfully applied to explore the virtual water flows across provinces in China.