bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of the electron ionization mass spectra of the Novichok nerve agent
Authors: Chernicharo Francisco C. S. , Modesto‐Costa Lucas , Borges Itamar 
Published: July 2021

AbstractNovichok is one of the most feared and controversial nerve agents, which existence was confirmed only after the Salisbury attack in 2018. A new attack on August 2020, in Russia, was confirmed. After the 2018 attack, the agent was included in the list of the most dangerous chemicals of the Chemical Weapons Convention (CWC). However, information related to its electron ionization mass spectrometry (EI/MS), essential for unambiguous identification, is scarce. Therefore, investigations about Novichok EI/MS are urgent. In this work, we employed Born–Oppenheimer molecular dynamics through the Quantum Chemistry Electron Ionization Mass Spectrometry (QCEIMS) method to simulate and rationalize the EI/MS spectra and fragmentation pathways of 32 Novichok molecules recently incorporated into the CWC. The comparison of additional simulations with the measured EI spectrum of another Novichok analog is very favorable. A general scheme of the fragmentation pathways derived from simulation results was presented. The present results will be useful for elucidation and prediction of the EI spectra and fragmentation pathways of the dangerous Novichok nerve agent.
Evaluation of a SARS‐CoV‐2 antigen‐detecting rapid diagnostic test as a self‐test: Diagnostic performance and usability
Authors: Cassuto Nino Guy , Gravier Anne , Colin Mathilda , Theillay Aurelie , Pires‐Roteira Daniela , Pallay Sandra , Serreau Raphael , Hocqueloux Laurent , Prazuck Thierry 
Published: July 2021

AbstractTo control the spread of the coronavirus disease 2019 (COVID‐19) epidemics, it is necessary to have easy‐to‐use, reliable diagnostic tests available. The nasopharyngeal sampling method being often uncomfortable, nasal sampling could prove to be a viable alternative to the reference sampling method. We performed a multicentre, prospective validation study of the COVID‐VIRO® test, using a nasal swab sampling method, in a point‐of‐care setting. In addition, we performed a multicentre, prospective, and usability study to validate the use of the rapid antigen nasal diagnostic test by laypersons. In March 2021, 239 asymptomatic and symptomatic patients were included in the validation study. Compared with reverse‐transcription polymerase chain reaction on nasopharyngeal samples, the sensitivity and specificity of the COVID‐VIRO® Antigen test combined with a nasal sampling method were evaluated as 96.88% and 100%, respectively. A total of 101 individuals were included in the usability study. Among these, 99% of the participants rated the instructions material as good, 98% of the subjects executed the test procedure well, and 98% of the participants were able to correctly interpret the test results. This study validates the relevance of COVID‐VIRO® as a diagnostic tool from nasal specimens as well as its usability in the general population. COVID‐VIRO® diagnostic performances and ease of use make it suitable for widespread utilization.
Case studies of atmospheric moisture sources in the source region of the Yellow River from a Lagrangian perspective
Authors: Liu Rong , Wen Jun , Wang Xin , Wang Zuoliang , Liu Yu 
Published: July 2021

AbstractIn this study, atmospheric moisture source regions and transport pathways, which substantially affect extreme summer precipitation events in the source region of the Yellow River (SRYR) of China were investigated using the Lagrangian Flexible Particle Dispersion Model (FLEXPART). Based on the 24‐hour cumulative precipitation data from the China Meteorological Data Service Center, 2012 and 2015 were selected to represent wet and dry years during the period 2007–2016, respectively. The results indicate that potential moisture sources include the northern Tibetan Plateau, the Bay of Bengal, the southern edge of the Himalayas, Sichuan Basin, and the SRYR. In the wet year, moisture from the southern branch was transported along two pathways: (a) moisture from the Arabian Sea was carried by the Somalia jet and entered the SRYR through the Indian Peninsula and Bay of Bengal, and (b) moisture from the South China Sea entered the SRYR through the Sichuan Basin. In the dry year, the moisture primary originated from the northern branch. Moisture from the eastern European Plain or northern Africa was carried by the westerly jet and entered the SRYR. It is estimated that the ratios of moisture from the northern and southern branches contributing to the precipitation in the SRYR were 22.1 and 15.9% in the wet year, while they were 52.9 and 8.4% in the dry year, respectively. Internal moisture recycling contributed ~22.0% to precipitation in the wet year and 11.0% in the dry year. In this study, the transport trajectories of moisture contributing to extreme precipitation events in the SRYR are delineated. The results indicate that the northern branch is the primary contributor of moisture in the SRYR.
The relationship between teleconnections, surface temperature, and cold air outbreaks
Authors: Smith Erik T. , Sheridan Scott C. 
Published: July 2021

AbstractCold air outbreaks (CAOs) are extreme events that can negatively impact the agricultural industry, human health, and cause widespread power outages from increased energy consumption. Increasing the predictability of CAOs is critical to limiting the adverse impacts on society, but skilful predictions rely on well‐defined mechanisms of causation. To improve the understanding of CAO mechanisms, this study examines the relationship between atmospheric and oceanic teleconnection indices and CAOs in the Northern Hemisphere (NH) during two distinct periods, 1979–1998 and 1999–2018. Changes in the relationship between CAOs and teleconnections during these two periods are calculated and used to determine the teleconnections that currently have the strongest relationship with CAOs across the NH. Several relationships were found to no longer be significant while several other significant relationships have emerged, particularly with the Tropical Northern Hemisphere (TNH) pattern. Furthermore, upstream teleconnections, as opposed to downstream teleconnections, were generally found to have a stronger relationship with CAOs. The East Pacific Oscillation and East Pacific/North Pacific pattern were found to have the strongest relationship with CAOs in the eastern U.S. and Alaska, while the Arctic Oscillation, North Atlantic Oscillation, Greenland Blocking Index, and Scandinavian pattern have the strongest relationship with CAOs in Eurasia.
The spatial and seasonal dependency of daily precipitation extremes on the temperature in China from 1957 to 2017
Authors: Chen Wenhui , Cui Huijuan , Ge Quansheng 
Published: July 2021

AbstractThe frequency and intensity of extreme precipitation in China increase generally with global warming. It is well‐accepted that higher temperature increases water vapour in the atmosphere, leading to more extreme precipitation events. Assuming relative humidity stay constant, the Clausius–Clapeyron (C–C) relationship indicates that global precipitation extremes increase with temperature at a rate of approximately 7%/°C. This study investigated the dependency of daily precipitation extremes on the temperature using daily data of 525 stations in China during 1957–2017. Results showed that the peak structure and sub C–C scaling (0%/°C–5%/°C) were dominant in China, while the scaling rates exhibited a ‘sub C–C, C–C like or super C–C, negative C–C’ trend from southeast to northwest over China. The upper quartile of precipitation (P75) were more sensitive to temperature change than higher intensities. Unlike the scaling patterns in the whole year, the negative relationships were found dominant in most areas in summer, indicating that as summer's lowest temperature reaches the peak of the year, the negative scaling of extreme precipitation at higher temperatures were reinforced.
Projected impacts of 1.5 and 2°C global warming on temperature and precipitation patterns in South America
Authors: Torres Roger Rodrigues , Benassi Rafael Bitencourt , Martins Fabrina Bolzan , Lapola David Montenegro 
Published: July 2021

AbstractEven if the thresholds set out in the Paris Agreement are reached, several impacts on the climate system are still inevitable, generating new vulnerabilities and amplifying those that already exist. In this sense, the objective of this work was to analyse the impact of a global warming of 1.5 and 2°C in the regional climatological patterns of the near‐surface air temperature and precipitation over South America, locating the most affected regions and briefly discussing the possible impacts to be faced on biodiversity and agriculture. The simulations and projections of 26 General Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 were used, forced in four different Representative Concentration Pathways (RCPs) scenarios. Projections for 1.5 or 2°C global warming indicate a local increase even higher, of at least +0.5°C, in almost the entire South American continent. Regarding precipitation, a similar pattern was also found between the two thresholds of global warming. GCMs project an increase of about 100 mm year−1 in the southern region of Brazil and in the northern portion of the Brazilian Northeast, in northern Argentina, Uruguay, and parts of Peru, Ecuador, Colombia and Venezuela; while the areas between the south of Chile and Argentina and the extreme north of South America show reductions of up to 150 mm year−1. In addition, both the temperature and precipitation patterns were practically similar between the four analysed RCPs scenarios. The results presented in this study indicate that even if the Paris Agreement is very successful, South America will still suffer several impacts and will need to take effective adaptation measures in the short term. This may have pervasive implications for the biodiversity and genetic resource base of the subcontinent, as well as may impair agricultural productivity or incur into considerable adaptation costs for the sector.
How do mistreated high‐status service providers compensate?
Authors: Mattar Dorine M. 
Published: July 2021

AbstractThis study aims to examine the reactions of high‐status service employees to customer mistreatment. An inductive research design is adopted, relying on the qualitative data collected from semi‐structured interviews conducted with university professors, doctors, and high‐ranking bank employees in Lebanon. High‐status service providers who experience mistreatment by their customers experience strong feelings and may suffer from flashbacks triggered by similar circumstances. The data reveals two forms of compensating reaction: surface acting and the withholding of customer‐oriented organizational citizenship behaviors from the customer who mistreated them. The former creates an open loop spiral which affects downstream customers whereas the latter stops with the customer who mistreated them. The study contributes to the existing literature on customers' mistreatment, which has tended to focus on low‐status employees in traditional service contexts. In addition, as it was conducted in a society with a collectivistic culture it also provides valuable insights into the role played by culture. Finally, it contributes to management practice by helping managers recognize the impact of the mistreatment of high‐status service providers and to channel their subordinates' negative emotions into a more positive outcome.
Assessing salt marsh loss and degradation by combining long‐term LANDSAT imagery and numerical modelling
Authors: Lopes Carina L. , Mendes Renato , Caçador Isabel , Dias João M. 
Published: July 2021

AbstractThe precise evaluation of the conservation status of salt marshes, the understanding of the mechanisms behind loss and degradation and the anticipation of future threats are fundamental to assist management solutions able to reverse the declining trend observed in these environments. Previous methods combining remote sensing and hydrodynamic modelling have been revealed to be effective in assessing degradation in restricted marshes, but unable to characterise dynamics of marshes at the estuarine scale. This study proposes an alternative methodology to identify priority areas for conservation by combining LANDSAT satellite remote sensing and numerical modelling. Using the Ria de Aveiro as case‐study, the main objectives of this work are to: (1) identify vegetation loss and degradation in estuarine marshes; (2) determine the mechanisms behind marsh deterioration; (3) anticipate future threats posed by climate‐induced mean sea level rise and; (4) provide management solutions aiming to protect and recover degraded salt marshes. LANDSAT imagery reveals that the most deteriorated salt marshes are located on the central and upper lagoon regions, and the numerical results support that marsh loss and degradation result from the increased tidal action triggered by the deepening of the lagoon channels. The increase in tidal currents promoted the erosion of marsh shoreline, whereas the changes in the inundation patterns over the intertidal areas triggered interior drowning. Climate‐induced mean sea level rise will likely exacerbate marsh deterioration, increasing the urgency to implement a management plan aiming to protect marshes from erosion and promote sedimentation in submerged marshes, to ensure their sustainability.
Approximate solutions of vector fields and an application to Denjoy–Carleman regularity of solutions of a nonlinear PDE
Authors: Braun Rodrigues Nicholas , da Silva Antonio Victor 
Published: July 2021

AbstractIn this paper we study microlocal regularity of a ‐solution u of the equation
where is ultradifferentiable in the variables and holomorphic in the variables . We proved that if is a regular Denjoy–Carleman class (including the quasianalytic case) then:
where is the Denjoy–Carleman wave‐front set of u and is the characteristic set of the linearized operator :
The utility of free abdominal flap without Zone 4 procedure for unilateral breast reconstruction
Authors: Tokumoto Hideki , Akita Shinsuke , Kubota Yoshitaka , Mitsukawa Nobuyuki 
Published: July 2021

AbstractBackgroundThe perfusion concept of free abdominal flap for breast reconstruction shares the common perception. We believed that free abdominal flap without Zone 4 could be performed. The purpose of this study is to introduce the “without Zone 4 procedure” and compare with the conventional technique (without 4 vs. conventional groups).MethodsThe “without 4 group” included 61 patients, while the conventional group 55 patients. The inclusion criterion for the “without Zone 4 procedure” was defined as the thickest part of flap was more than half of the contralateral breast projection. The centerline of the skin island was adjusted to the position with the most medial side of the perforator. We compared basic characteristics (age, BMI, operation time, blood loss, contralateral breast size, smoking status, and history of laparotomy), the flaps' horizontal and vertical widths, thickness of the thickest part of the flap, elevated flap weight, and operative procedure.ResultsThe mean length of the flaps' horizontal width was significantly shorter (19.2 cm vs. 26.3 cm; p < .001) and the mean flap thickness was significantly greater in the without 4 group. The mean contralateral breast height and projection length were significantly longer in the conventional group. No significant differences were found with respect to the other characteristics.ConclusionsPatients with a lower breast projection compared with the abdominal fat thickness could undergo reconstruction with a shorter flap horizontal width. Because of the esthetic outcome of the donor site, this procedure is more appropriate for low‐BMI patients.
Unbiased signal equation for quantitative magnetization transfer mapping in balanced steady‐state free precession MRI
Authors: Bayer Fritz M. , Bock Michael , Jezzard Peter , Smith Alex K. 
Published: July 2021

PurposeQuantitative magnetization transfer (qMT) imaging can be used to quantify the proportion of protons in a voxel attached to macromolecules. Here, we show that the original qMT balanced steady‐state free precession (bSSFP) model is biased due to over‐simplistic assumptions made in its derivation.Theory and MethodsWe present an improved model for qMT bSSFP, which incorporates finite radiofrequency (RF) pulse effects as well as simultaneous exchange and relaxation. Furthermore, a correction relating to finite RF pulse effects for sinc‐shaped excitations is derived. The new model is compared to the original one in numerical simulations of the Bloch‐McConnell equations and in previously acquired in vivo data.ResultsOur numerical simulations show that the original signal equation is significantly biased in typical brain tissue structures (by 7%‐20%), whereas the new signal equation outperforms the original one with minimal bias (<1%). It is further shown that the bias of the original model strongly affects the acquired qMT parameters in human brain structures, with differences in the clinically relevant parameter of pool‐size‐ratio of up to 31%. Particularly high biases of the original signal equation are expected in an MS lesion within diseased brain tissue (due to a low T2/T1‐ratio), demanding a more accurate model for clinical applications.ConclusionThe improved model for qMT bSSFP is recommended for accurate qMT parameter mapping in healthy and diseased brain tissue structures.
Evaluation of students' perceived clinical competence and learning needs following an online virtual simulation education programme with debriefing during the COVID‐19 pandemic
Authors: Fung John Tai Chun , Zhang Wen , Yeung Man Nga , Pang Michelle Tsz Ha , Lam Veronica Suk Fun , Chan Bobo Kai Yin , Wong Janet Yuen‐Ha 
Published: July 2021

AbstractAims and objectivesThis study aimed to evaluate the effect of a virtual simulation education programme with debriefing in undergraduate nursing students. Perceived clinical competence and learning needs of students in a simulation environment were also measured.BackgroundEvidence showed virtual simulation education programmes provided better knowledge acquisition. However, these studies to date did not incorporate virtual simulation in the combination of a debriefing model in nursing students.DesignA one‐group pre‐test and post‐test design.Methods188 final year undergraduate nursing students participated in the study. Linear mixed model analysis was conducted to evaluate the effect of the programme.ResultsStudents have perceived a significant improvement in clinical competence and nursing process. Self‐efficacy has also boosted. Communication and critical thinking were applied better in the traditional clinical environment.ConclusionPerceived clinical competence of Chinese nursing students has significant improvements by using virtual simulation combining a debriefing model during the COVID‐19 period. Virtual simulation met students' learning needs. Future studies should include a control group for comparison and long‐term measurement.Relevance to clinical practiceThe study provided an innovative clinical learning pedagogy to serve as a potential alternative with traditional clinical practicum during the COVID‐19 period as this is substantially limited.
Constrained nonlinear model predictive control of pH value in wet flue gas desulfurization process
Authors: Li Xiaoli , Dong Jiawei , Wang Kang 
Published: July 2021

AbstractIn wet flue gas desulfurization (WFGD) process, the pH value of the absorption tower slurry is a crucial factor to the efficiency of desulfurization system. Aiming at the nonlinearity and large lag of the pH change in WFGD process, a predictive control strategy based on Hammerstein–Wiener inverse model compensation is proposed. During the calculation of optimal control, an anti‐model of Wiener nonlinearity unit is adopted to transform the output setting values and sampling values. Similarly in the control process, the controller output is applied to the actual controlled object after inverse transformation of the static nonlinear Hammerstein model. Through the above two inverse transformations, the controller output is identical with the input of linear link in the closed‐loop system. In this article, the inverse model compensation method is utilized to transform nonlinear process control into linear system control, avoiding the large computation of nonlinear model optimization. Finally, the feasibility and effectiveness of the proposed scheme are verified by simulation.
Preparation of shape memory polyurethane/modified cellulose nanocrystals composites with balanced comprehensive performances
Authors: Du Weining , Zhang Zejiang , Yin Chaolu , Ge Xinguo , Shi Liangjie 
Published: July 2021

AbstractIn this work, we first synthesized modified cellulose nanocrystals (MCNC) with 2,4‐toluene diisocyanate and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide via a two‐step in‐situ polymerization method, and then incorporated it with shape memory polyurethane (SMPU) to fabricate composite. It was found that the urethane chains and phosphorus‐containing flame retardant were covalently grafted onto the cellulose nanocrystals surface, and the MCNC exhibited good dispersion level in the SMPU matrix. Due to the crystallization‐induced and flame retardant effects of the prepared MCNC, it could be acted as a multifunctional reinforcer in SMPU composites. Noticeably, the most balanced improvements in crystallization, shape memory, mechanical, thermal stability, and flame retardancy properties of composites were observed with the incorporation of 3 wt% MCNC. Shape memory experiment demonstrated that the SMPU‐MCNC3 composite exhibited admirable thermal induced shape memory behavior, and its shape fixity and shape recovery ratios were maintained above 90% after five cycles. More importantly, the SMPU‐MCNC3 composite showed well balanced mechanical (σb = 13.1 MPa, εb = 189.3%), limiting oxygen index (23.8%), and UL‐94 rating (V‐2) among the prepared polyurethane films. In addition, the representative SMPU‐MCNC3 showed obviously reductions in heat and smoke production during combustion as compared to the neat SMPU. The present work offers a promising route to fabricate shape memory polyurethane composites with versatile functions.