bluuebunny/crossref_metadata_2025 huggingface dataset:
Short-term exposure to ambient air pollution and individual emergency department visits for COVID-19: a case-crossover study in Canada
Authors: Lavigne Eric , Ryti Niilo , Gasparrini Antonio , Sera Francesco , Weichenthal Scott , Chen Hong , To Teresa , Evans Greg J , Sun Liu , Dheri Aman , Lemogo Lionnel , Kotchi Serge Olivier , Stieb Dave
Published: March 2022

Background

Ambient air pollution is thought to contribute to increased risk of COVID-19, but the evidence is controversial.

Objective

To evaluate the associations between short-term variations in outdoor concentrations of ambient air pollution and COVID-19 emergency department (ED) visits.

Methods

We conducted a case-crossover study of 78 255 COVID-19 ED visits in Alberta and Ontario, Canada between 1 March 2020 and 31 March 2021. Daily air pollution data (ie, fine particulate matter with diameter less than 2.5 µm (PM2.5), nitrogen dioxide (NO2) and ozone were assigned to individual case of COVID-19 in 10 km × 10 km grid resolution. Conditional logistic regression was used to estimate associations between air pollution and ED visits for COVID-19.

Results

Cumulative ambient exposure over 0–3 days to PM2.5 (OR 1.010; 95% CI 1.004 to 1.015, per 6.2 µg/m3) and NO2(OR 1.021; 95% CI 1.015 to 1.028, per 7.7 ppb) concentrations were associated with ED visits for COVID-19. We found that the association between PM2.5and COVID-19 ED visits was stronger among those hospitalised following an ED visit, as a measure of disease severity, (OR 1.023; 95% CI 1.015 to 1.031) compared with those not hospitalised (OR 0.992; 95% CI 0.980 to 1.004) (p value for effect modification=0.04).

Conclusions

We found associations between short-term exposure to ambient air pollutants and COVID-19 ED visits. Exposure to air pollution may also lead to more severe COVID-19 disease.
A single dose of dietary nitrate supplementation protects against endothelial ischemia–reperfusion injury in early postmenopausal women
Authors: Somani Y.B. , Soares R.N. , Gosalia J. , Delgado J.M. , Flanagan M. , Basu S. , Kim-Shapiro D.B. , Murias J.M. , Proctor D.N.
Published: March 2022

The onset of menopause and accompanying changes to ovarian hormones often precedes endothelial dysfunction in women. In particular, accelerated impairments in macrovascular and microvascular function coincide with the loss of estrogen, as does impaired endothelial responses to ischemia–reperfusion (IR) injury. In healthy, early postmenopausal women ( n = 12; 3.9 ± 1.5 years since menopause) we tested the hypothesis that acute dietary nitrate (NO3−) supplementation would improve endothelial function and attenuate the magnitude of endothelial dysfunction following whole-arm IR in comparison with placebo. In this randomized, double-blind, placebo-controlled, crossover study we tested participants before and after NO3−-rich (BRnitrate) and NO3−-depleted (BRplacebo) beetroot juice (BR) consumption, as well as following IR injury, and 15 min after IR to assess recovery. Analyses with repeated-measures general linear models revealed a condition × time interaction for brachial artery flow-mediated dilation (FMD; P = 0.04), and no interaction effect was found for the near-infrared spectroscopy-derived reperfusion slope ( P = 0.86). Follow-up analysis showed a significant decline in FMD following IR injury with BRplacebo in comparison with all other timepoints (all, P < 0.05), while this decline was not present with BRnitrate (all, P > 0.05). Our findings demonstrate that a single dose of dietary NO3− minimizes IR-induced macrovascular endothelial dysfunction in healthy, early postmenopausal women, but does not improve resting macrovascular and microvascular function. Trial registration number: NCT03644472.

Novelty:

In healthy, early postmenopausal women, a single dose of NO3−-rich BR can protect against IR-induced endothelial dysfunction. This protection may be due to nitric oxide bioactivity during IR rather than improved endothelial function prior to the IR protocol per se.
Northwest Atlantic redfish science priorities for managing an enigmatic species complex
Authors: Cadigan Noel G. , Duplisea D.E. , Senay C. , Parent G.J. , Winger P.D. , Linton B. , Kristinsson K.
Published: March 2022

Redfish ( Sebastes spp.) in the Northwest Atlantic (NWA) extend from Baffin Island in the north to the Gulf of Maine in the south. The two most abundant species are Sebastes mentella and Sebastes fasciatus, which are morphometrically similar and difficult to visually distinguish. Redfish are long-lived, slow-growing, late-maturing, tend to produce large year classes episodically, and have complex population structure. Intraspecific genetic groups are abundant in the NWA. They are often semipelagic and patchily distributed, which makes them difficult to survey. These are all characteristics that cause difficulties for stock assessment and for sustainable fisheries management. This was the focus of The Ocean Frontier Institute Northwest Atlantic Redfish Symposium in 2018. In this paper, we synthesize the information known about NWA redfish. To improve the scientific basis for sustainable harvest strategies, key research recommendations involve (1) improved biological sampling including species and ecotype; (2) developing integrated stock assessment models; (3) developing harvest strategies with management reference points that are appropriate for redfish; (4) improving fishing technology and practices to avoid capture of small nonmarketable redfish and other species.
Multi-body modelling and adaptive control of a re-configurable uninhabited airship
Authors: Tuta-Navajas Gilmar , Lanteigne Eric
Published: March 2022

This paper presents pitch control of an uninhabited airship using changes in center of gravity. Changes in center of gravity are achieved by controlling the position of a movable gondola along a rigid keel fixed to the bow of the helium envelope. The longitudinal multi-body dynamic equations of motion were developed using the measured and estimated physical properties and an adaptive PID controller was designed to control the pitch angle. Flight tests on a 4 m long uninhabited airship prototype were conducted to demonstrate the effectiveness of the method.
Protecting expert advice for the public: promoting safety and improved communications
Authors: Wright Julia M. , Chun Wendy Hui Kyong , Clarke Amanda , Herder Matthew , Ramos Howard
Published: March 2022

The drivers of the harassment and intimidation of researchers are complex, widespread, and global in their reach and were being studied across many disciplines even before COVID-19. This policy briefing reviews some of the scholarship on this wide-ranging problem but focuses on what can be done to help ensure that Canadians fully benefit from the work of Canada’s researchers while also preserving the security and safety of those researchers. It identifies policies and actions that can be implemented in the near term to gather information on the problem, better frame public research communications, and ensure that mechanisms are readily available to support researchers who are threatened. The policy briefing is concerned with researchers, but these behaviours are also harming journalists, politicians, public health communicators, and many others more fully in the public eye than researchers. Some recommendations here may help to address this wider problem.
Electrodeposited MoS2 film on nickel foam as a binder-free electrode for supercapacitors
Authors: Zhao Xin , Tian Lecheng , Wang Hongyan , Xing Zhicai
Published: March 2022

In this work, MoS2 was successfully deposited on Ni foam (NF) by a simple one-step electrochemical deposition method. MoS2 were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectrum (XPS) and energy dispersive spectrometer (EDS). XRD and FESEM results show that MoS2 is an amorphous film structure. The electrochemical properties of the MoS2 electrode have been studied in detail via cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopic (EIS) technology, respectively. The MoS2/NF binder-free electrode provides a special capacitance of 210 F/g at a constant discharge current density of 1 A/g. When the current density increases five times, the specific capacitance can still maintain 51.74% of the initial capacitance. In addition, after 1000 cycles at 3 A/g, the capacitance retention of the MoS2 electrode still retained 79.4%.
Two new integrable differential-difference hierarchies related to the relativistic Toda lattice equation and their soliton fusion or fission
Authors: Wang Hongyan , Zhu Guoqing
Published: March 2022

Starting from a discrete spectral problem, two new integrable differential-difference hierarchies are presented and their Lax pairs are given, respectively. The first hierarchy is related to the relativistic Toda lattice equation. Darboux transformations for the first systems in the two hierarchies are derived, respectively, accordingly their explicit solutions are obtained. By selecting appropriate parameters, we can see the phenomena of soliton fission or soliton fusion.
New exact solutions to the coupled (n + 1)-dimensional Klein–Gordon–Zakharov equation with power law nonlinearities
Authors: Peng Li , Zhang Ning
Published: March 2022

In this paper, a special class of exact solutions of the coupled higher-dimensional Klein–Gordon–Zakharov (KGZ) equation with power law nonlinearities is constructed explicitly by separation transformation method. One merit of this work is that when the dimension is larger than one, there is an arbitrary function [Formula: see text], which is used to search for more general exact solutions of the coupled higher-dimensional KGZ equation. As a result, the Jacobi elliptic function solutions and soliton solutions with free parameters are derived, which lead to rich localized nonlinear structures of the coupled higher-dimensional KGZ equation with power law nonlinearities.
Influence of the Coexisting Attractors on the Slow–Fast Behaviors in the Fast Subsystem
Authors: Zhao Jiahao , Xia Yibo , Zhang Xiaofang , Bi Qinsheng
Published: March 2022

This paper is devoted to exploring the effect of the coexisting attractors in the fast subsystem of a full nonlinear system on the complex dynamics. As an example, a modified 3D van der Pol–Duffing circuit is discussed, in which the coexistence of five attractors including a hidden one was reported in 2020. By introducing a parametric excitation, when the exciting frequency is far less than the natural frequency, a slow–fast model with the two-scale coupling is established in the frequency domain. Regarding the exciting term as a slow-varying parameter, all the attractors as well as the bifurcations of the fast subsystem are derived. The coexistence conditions as well as the coexisting attractors, including the equilibrium points and limit cycles, are presented. With the variation of the exciting amplitude, different types of bursting oscillations are observed, the mechanism of which is revealed using a modified slow–fast analysis method, by combining the transformed phase portraits and the attractors as well as the bifurcations. It is found that the coexisting attractors of the fast subsystem may lead to coexisting bursting solutions in the full system, in which a trajectory may visit one of the attracting basins of the attractors, or result in a merged bursting motion, which may visit the attracting basins in turn. The influence of some attractors and the associated bifurcations may vanish in the case that the trajectory passes directly across the parameter interval corresponding to the attractors because of the inertia of the motion; this may also occur in the case that the trajectory does not visit the associated attracting basins, but it starts initially from the basins. It should be pointed out that, when the exciting frequency is small enough, the disappeared effect of stable attractors may reoccur. Furthermore, if the parameter interval between two types of codimension-1 bifurcation points is short enough, the trajectory may behave in a combination of two bifurcations, which is somewhat similar to that caused by a codimension-2 bifurcation.
A Random Irregular Blocking Image Encryption Algorithm Based on Improved Digital Chaotic Maps at Bit Level
Authors: Xiang Hongyue , Liu Lingfeng
Published: March 2022

To improve the security level of image encryption based on chaos theory, a novel bit-level transform method which could enhance the dynamical performance of chaotic maps is proposed and a new image encryption algorithm based on a random irregular blocking method is also designed in this paper. Firstly, in the bit-level transform method, three chaotic maps are combined to generate a novel chaotic sequence. From a series of performance analyses results, the generated sequence not only successfully passes NIST tests, but also performs better than the original sequence, with a larger chaotic parametrial range, high complexity, etc. Then, an image encryption algorithm based on the newly generated chaotic sequence is proposed, in which a random irregular blocking method is adopted. Random irregular blocking could solve the problem of insecurity in the fixed blocking method. With a color Lena image as an encryption example, we analyze the security of the encryption algorithm by conducting a sufficiently large number of experiments using the encrypted image. For the encrypted Lena image, the average values of information entropy, NPCR, and UACI are 7.9931, 0.9961, and 0.3352, respectively. The experimental results and security analyses results provide evidence that the proposed encryption algorithm has good performance and can resist various typical attacks.
Foliation of Schwarzschild, Reissner–Nordström and suture universe model metrics revisited
Authors: Qadir Asghar
Published: March 2022

I had worked with John Wheeler on York-time foliation of a black hole in a closed Universe (1978–1993), on my own, and with my students, Amjad Parvez and Azad Siddiqui, on that and foliation of asymptotically flat black hole spacetimes from then till 2013. In July 2021, the work by Gerard ’t Hooft and others, presented in MG16, seemed to have “rediscovered” what we had found much earlier. The work of Roy Kerr and others displayed confusion that could be cleared up by those insights. I review this material.
Gravastars with Karmarkar condition in f(ℜ,𝒯2) gravity
Authors: Sharif M. , Naz Saba
Published: March 2022

This paper examines the structure of gravastar (gravitationally vacuum star) in the background of [Formula: see text] theory. The gravastar can be regarded as a substitute for a black hole comprising of three regions (i) the interior domain, (ii) the intrinsic shell and (iii) the exterior domain. We investigate these domains by employing Karmarkar’s condition by assuming a specific [Formula: see text] model. The field equations are solved to evaluate nonsingular solutions of both the interior and intermediate regions. Inner as well as outer spacetimes are matched together using Israel formalism to obtain density and pressure at the joining surface. Different attributes of gravastar like the equation of state parameter, proper length, entropy and energy are analyzed through graphical behavior. It is found that the gravastar model is a viable alternative to the black hole in the context of this gravity.
EFFECT OF PLATELET-RICH FIBRIN ON BIOMECHANICAL AND BIOCHEMICAL ASPECTS OF TENDON HEALING: A PRELIMINARY ANIMAL STUDY
Authors: Yousefi Amir Reza , Kazemi Davoud , Rezaei Mostafa
Published: March 2022

Purpose: To investigate the effect of platelet-rich fibrin as a rich source of growth factors on biomechanical and biochemical aspects of tendon healing. Methods: Tendon defects were created in six adult male mixed breed dogs by surgical resection of the central third of the patellar tendon of both hind limbs. The defects were either treated by platelet-rich fibrin implantation or left empty. The animals were euthanized one, three and six months after surgery and their patellar tendons harvested for determination of ultimate stress, ultimate strain, tensile strength and Young’s modulus of elasticity along with hydroxyproline content. Results: Significant differences were not observed in mean values of the measured biomechanical and biochemical parameters at any time point between the two groups. Conclusions: Based on the results of the present study, PRF did not have a positive influence on biomechanical and biochemical aspects of tendon healing in dogs.
Transition Waves in One-Dimensional Periodic Bistable Mass-Spring Chains
Authors: Chen Lin , Xu Ao , Lou Jia , Wu Huaping
Published: March 2022

The propagation of transition waves in multi-stable mechanical systems can be effectively harnessed in various fields, such as mechanical signal communication, mechanical diodes, and energy absorption. In this work, the propagation of transition waves in a one-dimensional (1D) bistable mass-spring chain is systematically studied. The underlying physical mechanism for the formation and propagation of transition waves is clarified, and the influences of some crucial factors, such as the pumped momentum, stiffness of the connecting springs, viscous damping, number of masses, and asymmetry of the double-well potential, on the propagation of transition waves are discussed in detail. As a result, the parameter space for achieving the robust propagation of transition waves through the whole chain is presented. This study is expected to be beneficial for the control of transition waves and design of novel devices used for mechanical signal transmission.
SIMULATION OF DIABETIC RETINOPATHY UTILIZING CONVOLUTIONAL NEURAL NETWORKS
Authors: RAJARAJESWARI P. , MOORTHY JAYASHREE , BÉG O. ANWAR
Published: March 2022

Currently, diabetic retinopathy is still screened as a three-stage classification, which is a tedious strategy and along these lines of this paper focuses on developing an improved methodology. In this methodology, we taught a convolutional neural network form on a major dataset, which includes around 45 depictions to do mathematical analysis and characterization. In this paper, DR is constructed, which takes the enter parameters as the HRF fundus photo of the eye. Three classes of patients are considered — healthy patients, diabetic’s retinopathy patients and glaucoma patients. An informed convolutional neural system without a fully connected model will also separate the highlights of the fundus pixel with the help of the enactment abilities like ReLu and softmax and arrangement. The yield obtained from the convolutional neural network (CNN) model and patient data achieves an institutionalized 97% accuracy. Therefore, the resulting methodology is having a great potential benefiting ophthalmic specialists in clinical medicine in terms of diagnosing earlier the symptoms of DR and mitigating its effects.
Methods for Detecting COVID-19 Patients Using Interval-Valued T-Spherical Fuzzy Relations and Information Measures
Authors: Wang Yinyu , Ullah Kifayat , Mahmood Tahir , Garg Harish , Zedam Lemnaouar , Zeng Shouzhen , Li Xingsen
Published: March 2022

The concepts of relations and information measures have importance whenever we deal with medical diagnosis problems. The aim of this paper is to investigate the global pandemic COVID-19 scenario using relations and information measures in an interval-valued T-spherical fuzzy (IVTSF) environment. An IVTSF set (IVTSFS) allows describing four aspects of human opinions i.e., membership, abstinence, non-membership, and refusal grade that process information in a significant way and reduce information loss. We propose similarity measures and relations in the IVTSF environment and investigate their properties. Both information measures and relations are applied in a medical diagnosis problem keeping in view the global pandemic COVID-19. How to determine the diagnosis based on symptoms of a patient using similarity measures and relations is discussed. Finally, the advantages of dealing with such problems using the IVTSF framework are demonstrated with examples.
Humanoids’ Feet: State-of-the-Art & Future Directions
Authors: Frizza Irene , Ayusawa Ko , Cherubini Andrea , Kaminaga Hiroshi , Fraisse Philippe , Venture Gentiane
Published: March 2022

Robotic feet play a fundamental role in the walking performance of a biped robot. Feet are essential to maintain dynamic stability and to propel the body during walking. They may ensure stability on uneven terrains. Yet, complex feet are seldom used on humanoids. This paper surveys 36 types of robotic feet we found in the literature. We classified them according to strategy, capabilities, structure, number of degrees of freedom, actuation method of ankle and foot, type of actuator, sensorization and type of control. Subsequently, we analyzed the dynamic and static models of flexible feet. We discussed considerations on foot dynamics or kinematics in the robot’s whole body control system. We analyzed both active joints control for feet including actuated joints, and control for feet with elastic elements (for example, a rubber layer in the sole). Finally, we present some limitations of robotic feet and possible future developments.
Thermodynamics of spacetime and unimodular gravity
Authors: Alonso-Serrano A. , Liška M.
Published: March 2022

In this review, we discuss the emergence of unimodular gravity (or, more precisely, Weyl transverse gravity) from the thermodynamics of spacetime. By analyzing three different ways to obtain gravitational equations of motion by thermodynamic arguments, we show that the results point to unimodular rather than fully diffeomorphism invariant theories and that this is true even for modified gravity. The unimodular character of dynamics is especially evident from the status of cosmological constant and energy-momentum conservation.
A Combination Weighting Method for the Risk Evaluation of Water Saving Management Contract
Authors: Chen Jiqiang , Zhang Lina , Zhang Feng , Ma Litao , Gao Linqing , Ha Minghu
Published: March 2022

At present, the shortage of water resources has severely restricted the sustainable development of economy in China, and water saving management contract (WSMC) is an important measure to effectively alleviate the problem of water shortage. However, the complexity of WSMC projects makes it difficult for water saving service enterprises to distinguish the risk of different projects. Therefore, based on combination weighting method, this paper tries to establish a risk evaluation method for WSMC projects. First, the risk evaluation index system of WSMC is constructed via the hierarchical holographic modeling method. Second, to evaluate the risk of different projects, a score function is defined to reflect the statistical dispersion of the comprehensive risk of each project, and then a multiple objective optimization problem is constructed. Third, after solving this optimization problem, a comprehensive risk score function is defined, and then a combination weighting method for the risk evaluation of WSMC project, which effectively incorporate expert knowledge and historical data, is established combing with the analytic hierarchy process and anti-entropy method. Finally, numerical examples are given to verify the feasibility of the proposed method. The proposed method not only enriches the research on the risk evaluation method of WSMC projects, but also provides reference for the project selection of water saving service enterprises.
Ring artifacts removal in X-ray-induced acoustic computed tomography
Authors: Pandey Prabodh Kumar , Aggrawal Hari Om , Wang Siqi , Kim Kaitlyn , Liu An , Xiang Liangzhong
Published: March 2022

X-ray-induced acoustic computed tomography (XACT) is a hybrid imaging modality for detecting X-ray absorption distribution via ultrasound emission. It facilitates imaging from a single projection X-ray illumination, thus reducing the radiation exposure and improving imaging speed. Nonuniform detector response caused by the interference between multichannel data acquisition for ring array transducers and amplifier systems yields ring artifacts in the reconstructed XACT images, which compromises the image quality. We propose model-based algorithms for ring artifacts corrected XACT imaging and demonstrate their efficacy on numerical and experimental measurements. The corrected reconstructions indicate significantly reduced ring artifacts as compared to their conventional counterparts.
Quarantined! Examining the Effects of a Community-Wide Moderation Intervention on Reddit
Authors: Chandrasekharan Eshwar , Jhaver Shagun , Bruckman Amy , Gilbert Eric
Published: March 2022

Should social media platforms override a community’s self-policing when it repeatedly break rules? What actions can they consider? In light of this debate, platforms have begun experimenting with softer alternatives to outright bans. We examine one such intervention called quarantining, that impedes direct access to and promotion of controversial communities. Specifically, we present two case studies of what happened when Reddit quarantined the influential communities r/TheRedPill (TRP) and r/The_Donald (TD). Using over 85M Reddit posts, we apply causal inference methods to examine the quarantine’s effects on TRP and TD. We find that the quarantine made it more difficult to recruit new members: new user influx to TRP and TD decreased by 79.5% and 58%, respectively. Despite quarantining, existing users’ misogyny and racism levels remained unaffected. We conclude by reflecting on the effectiveness of this design friction in limiting the influence of toxic communities and discuss broader implications for content moderation.
Recent Advances of Monocular 2D and 3D Human Pose Estimation: A Deep Learning Perspective
Authors: Liu Wu , Bao Qian , Sun Yu , Mei Tao
Published: March 2022

Estimation of the human pose from a monocular camera has been an emerging research topic in the computer vision community with many applications. Recently, benefiting from the deep learning technologies, a significant amount of research efforts have advanced the monocular human pose estimation both in 2D and 3D areas. Although there have been some works to summarize different approaches, it still remains challenging for researchers to have an in-depth view of how these approaches work from 2D to 3D. In this article, we provide a comprehensive and holistic 2D-to-3D perspective to tackle this problem. First, we comprehensively summarize the 2D and 3D representations of human body. Then, we summarize the mainstream and milestone approaches for these human body presentations since the year 2014 under unified frameworks. Especially, we provide insightful analyses for the intrinsic connections and methods evolution from 2D to 3D pose estimation. Furthermore, we analyze the solutions for challenging cases, such as the lack of data, the inherent ambiguity between 2D and 3D, and the complex multi-person scenarios. Next, we summarize the benchmarks, evaluation metrics, and the quantitative performance of popular approaches. Finally, we discuss the challenges and give deep thinking of promising directions for future research. We believe this survey will provide the readers (researchers, engineers, developers, etc.) with a deep and insightful understanding of monocular human pose estimation.
Explainable Deep Reinforcement Learning: State of the Art and Challenges
Authors: Vouros George A.
Published: March 2022

Interpretability, explainability, and transparency are key issues to introducing artificial intelligence methods in many critical domains. This is important due to ethical concerns and trust issues strongly connected to reliability, robustness, auditability, and fairness, and has important consequences toward keeping the human in the loop in high levels of automation, especially in critical cases for decision making, where both (human and the machine) play important roles. Although the research community has given much attention to explainability of closed (or black) prediction boxes, there are tremendous needs for explainability of closed-box methods that support agents to act autonomously in the real world. Reinforcement learning methods, and especially their deep versions, are such closed-box methods. In this article, we aim to provide a review of state-of-the-art methods for explainable deep reinforcement learning methods, taking also into account the needs of human operators—that is, of those who make the actual and critical decisions in solving real-world problems. We provide a formal specification of the deep reinforcement learning explainability problems, and we identify the necessary components of a general explainable reinforcement learning framework. Based on these, we provide a comprehensive review of state-of-the-art methods, categorizing them into classes according to the paradigm they follow, the interpretable models they use, and the surface representation of explanations provided. The article concludes by identifying open questions and important challenges.
Replicated Computational Results (RCR) Report for “A New Test for Hamming-Weight Dependencies”
Authors: Wu Xiaoliang , Jin Dong
Published: March 2022

In the paper “A New Test for Hamming-Weight Dependencies”, Blackman and Vigna propose a new statistical test for
pseudorandom number generators (PRNG)
. Compared with the state-of-the-art tests, the proposed test could find statistical bias in the Hamming weights of the output of the generator. The proposed test is evaluated by using generators in TestU01 [
2
]. The authors provide the C code used in the tests and the code successfully reproduced the results shown in the article.
Electrochemical Pressure Impedance Spectroscopy for Polymer Electrolyte Fuel Cells via Back-Pressure Control
Authors: Zhang Qingxin , Homayouni Hooman , Gates Byron D. , Eikerling Michael H. , Niroumand Amir M.
Published: March 2022

Electrochemical pressure impedance spectroscopy (EPIS) analyses the voltage response of a polymer electrolyte fuel cell (PEFC) as a function of an applied pressure signal in the frequency domain. EPIS is similar to electrochemical impedance spectroscopy (EIS) and its development was inspired by the diagnostic capabilities of the latter. The EPIS introduced in this work modulates the cathode pressure of a PEFC with a sinusoidal signal through the use of a back-pressure controller, and monitors the cell voltage while holding the cell at a constant current. A sinusoidal pressure wave propagates along the flow field channels because of this pressure modulation. This pressure wave impacts local reaction rates and transport properties in the cathode, resulting in a sinusoidal voltage response. The amplitude ratio and phase difference between these two sinusoidal waves entail diagnostic information on processes that take place within the PEFC. To demonstrate the utility of the EPIS technique, experiments have been carried out to measure and analyze the frequency response of PEFCs with two different flow fields. A parametric study has been conducted to characterize the effect of pressure oscillation amplitude, load, oxygen concentration, oxygen stoichiometry and cathode gas flow rate on the EPIS signal.
Rain Classroom assisted by WeChat for preliminary online physiology teaching during the COVID-19 pandemic
Authors: Feng Xiaoli , Mi Kai , Shen Yan , Hua Hairong , Bian Yan , Bian Hui
Published: March 2022

Due to the COVID-19 pandemic during spring semester 2020, teachers and students were forced to engage in online instruction. However, there is little evidence on the feasibility of online physiology teaching. This study demonstrated a 3-wk preliminary online physiology course based on Rain Classroom assisted by the mobile application WeChat. Eighty-seven nursing undergraduate students attended an online physiology course during the spring semester of the 2019–2020 academic year from March 9 to March 29. We determined the effects of the online physiology learning based on in-class tests, preclass preparation, and review rates for the course materials. We also measured the students’ perceptions and attitudes about online learning with a questionnaire survey. Posttest scores from the first week to the third week in online physiology course (7.22 ± 1.83, 7.68 ± 2.09, and 6.21 ± 2.92, respectively) exceeded the pretest scores (5.32 ± 2.14, 6.26 ± 2.49, and 3.72 ± 2.22, respectively), and this finding was statistically significant (all P < 0.001). Moreover, the pretest scores were significant positive predictors of final grade (all P < 0.01). In addition, the percentage of preclass preparation increased in 3 wk, from 43.68% to 57.47% to 68.97%. From the first week to the third week, the review rate increased from 86.21% to 91.95%; however, the second week was the lowest of all (72.41%). Finally, students’ perceptions about their online physiology learning experiences were favorable. In conclusion, online physiology instruction based on Rain Classroom assisted by WeChat was an effective strategy during the COVID-19 pandemic.
Research on the Depletion and Recovery Characteristics of Fault-Karst Reservoirs
Authors: Tang Bochao , Geng Chunying , Huang Mina , Lu Haitao , Ren Ke
Published: March 2022

A fractured-vuggy carbonate reservoir is a special reservoir formed by long-term physical, chemical, and geological processes. Its reserves are large in scale and widely distributed, showing the characteristics of free flow-seepage coupling. Conventional simulation is usually simplified by equivalent permeability, which cannot reflect the actual development characteristics. Given this, the flow in caves and fractures is treated with free flow, using the Navier–Stokes equation. The seepage simulation is used for other areas, and the Darcy formula is used. Finally, the simulation results are obtained by coupling, and the influence of oil production speed, fracture-cavity size, fracture-cavity location, dynamic viscosity, permeability, and other factors on bottom pressure is analyzed to effectively guide the field development. The results show that the production pressure of fractured-vuggy reservoirs diffuses from the central fractured-vuggy area to the surrounding matrix, and the pressure increases from the fractured-vuggy area to the surrounding matrix. The flow velocity in the seepage area is relatively stable and flows gently into the middle fracture cavity from all directions. There will be eddy current in the free-flow area. Different factors have different effects on the development. The oil production speed and oil dynamic viscosity are positively correlated with it, while the formation permeability is negatively correlated with it. The size and location distribution of fracture cavity will also have a certain impact. Simulation in advance can effectively avoid some reservoir development problems.
Design of a Novel Integral Sliding Mode-Based Composite Nonlinear Feedback Controller for Electrostatic MEMS Micromirror
Authors: Wu Jun , Zhu Wenbo , Guan Bingjie , Chen Hui
Published: March 2022

In this study, the precise tracking problem for electrostatic micromirror systems with disturbances and input saturation is investigated. Inspired by the composite nonlinear feedback (CNF)’s improvement of the transient performance and the sliding mode control’s enhancement of the robustness, a novel integral sliding mode with reaching law (ISMRL)-based composite nonlinear feedback (CNF) controller is proposed. Then, the stability of the closed-loop system is proved based on Lyapunov theorem. Finally, numerical simulations are investigated to evaluate the effectiveness of the proposed scheme. It is shown that the closed-loop system with the proposed scheme has precise positioning and improved transient performance in presence of time-varying disturbances.
Analytical and Numerical Analysis of the Squeezed Unsteady MHD Nanofluid Flow in the Presence of Thermal Radiation
Authors: Ullah Hakeem , Khan Muhammad Arif , Fiza Mehreen , Ullah Kashif , Ayaz Muhammad , Al-Mekhlafi Seham M.
Published: March 2022

In this study, the unsteady squeezing nanofluid flow between two plates with thermal radiation has been investigated. The governing equations of the flow model have been transformed to a set of nonlinear ordinary differential equations (ODEs) from a set of partial differential equations (PDEs) using a suitable similarity variable. The optimal auxiliary function method (OAFM) and Runge–Kutta method of order 4 (RK method of order 4) are used for the solution of the modeled problem. The variation of the squeezing number, Prandtl number, Eckert number, and thermal radiation has been presented. The magnetic field resists the flow velocity, and the Prandtl number resists the temperature distribution. The increase in volume fraction decreases the velocity profile whereas increases the temperature profile. The skin friction coefficient and the Nusselt number are inversely proportional to S. The effect of increasing values of Ec is to decrease the skin friction coefficient Cf and the heat transfer rate Nux. The increasing value of φ increases the skin friction coefficient and decreases the heat transfer rate.
Analysis on Medication Rules of Chinese Medicinal Herb Formulae in Uterine Subinvolution Treatment Based on Data Mining
Authors: Luo Jianghe , Yang Ming , Liu Yuling , Han Xinrui , Yue Wei
Published: March 2022

Introduction. Uterine subinvolution, especially the subinvolution of the placental site, can be a life-threatening disease that induces secondary postpartum hemorrhage (PPH). Chinese Herbal Medicine has been widely used to improve postpartum recovery and treat uterine subinvolution for thousands of years. Yet, there are many potential laws hidden that are worth exploring. Methods. Prescriptions treating uterine subinvolution were searched and collected to form datasets. Data mining methods including frequency analysis, cluster analysis, and association rule learning were performed to uncover the potent prescription laws of uterine subinvolution treatment. Results. A total of 803 formulae involving 249 herbs were obtained. The top 6 most frequently used herbs were Angelicae Sinensis Radix (Danggui), Chuanxiong Rhizoma (Chuanxiong), Leonuri Herba (Yimucao), Persicae Semen (Taoren), Zingiberis Rhizoma Preparatum (Paojiang), and Radix Glycyrrhizae Preparata (Zhigancao). Most of the 249 herbs were being warm in properties, sweet in tastes, and mainly distributed to liver and spleen meridian tropisms. Deficiency-tonifying herbs accounted for the most proportion and heat-clearing herbs ranked the second, followed by blood-activating and stasis-eliminating herbs. 6 clusters were generated by hierarchical clustering, and 5 of them were of clinical significance. 78 rules with support values over 0.25, confidence values over 0.8, and lift values greater than 1 were generated by association rule learning. Conclusion. The basic principles for uterine subinvolution treatment were deficiency-tonifying, heat-clearing, blood-activating, and stasis-eliminating. Herbs with warm properties, sweet tastes, and liver and spleen meridian tropisms are generally suitable. In addition, Sheng-Hua-Tang was the most frequently used formula for the treatment of uterine subinvolution, yet the dialectical prescriptions were diversified with different patterns/symptoms.
Judgment of Athlete Action Safety in Sports Competition Based on LSTM Recurrent Neural Network Algorithm
Authors: Liu Yanying , Wang Lijun , Tang Yuanjin , Ren Bo
Published: March 2022

Athlete injury has always been an important factor that plagues sports. In order to reduce the probability of athletes’ sports injury and improve the judgment of athletes’ action safety, the inherent laws of sports actions are fully excavated, the development of action safety is promoted, and learners and instructors are caused to fully understand the safety of actions. This study uses the LSTM (long short-term memory) cyclic neural network algorithm to judge the safety of athletes in sports competitions. The experiment verifies the effectiveness of the LSTM cyclic neural network algorithm in basketball segmentation and recognition. Sports injury is one of the important factors affecting the performance of all sports, and the problem of athletes’ injury is worrying, so it is very necessary to effectively prevent potential sports injuries. Through the investigation of different professional athletes, the LSTM cyclic neural network algorithm is used for the whole process of extracting an independent motion action including continuous actions. It is used to distinguish key postures and nonkey postures in an action, and to judge the correctness of the action. Basketball skills here are mainly the movements of basic skills such as moving, passing the ball, dribbling, shooting, breaking with the ball, personal defense, grabbing the ball, stealing the ball, and grabbing the ball. The research results prove that the LSTM recurrent neural network algorithm has a good effect on the safety of athletes. For athletes, 41.9% of people can improve the safety of their movements by strengthening strength training.
Curcumin Inhibits the Proliferation of Renal Cancer 786-O Cells through MTOR Signaling Pathway and Its Mechanism
Authors: Gao Rui , Ma Yunfang , Wang Yali , Xu Haili
Published: March 2022

Objectives. The mechanism of curcumin inhibiting renal cancer 786-O cells proliferation through MTOR signaling pathway was investigated. Methods. Human renal cancer 786-O cells were cultured with curcumin for 48 h. The OD values were measured by the MTT method, and the growth inhibition rate of 786-O cells was calculated. The cell cycle distribution and apoptosis rate were detected by flow cytometry (FCM). Transwell chamber was introduced to detect cell invasion ability. Cell migration ability was detected by the cell scratch test. The protein expression was assessed by Western blot. Results. With curcumin concentration increasing, the expressions of MMP2, MMP9, MTOR, and p-MTOR proteins and the number of cells in the S phase decreased gradually, while number of cells in G1 and G2/M phases and cells apoptosis rate increased continuously. With the increasing of concentration and time, growth of 786-O cells in each treatment group was inhibited to varying degrees. The higher the inhibition rate was, the cells migration and transmembrane cells proportion decreased significantly. Conclusions. Curcumin inhibits the proliferation, migration, and invasion and induces apoptosis of renal cancer 786-O cells by blocking the MTOR signaling pathway. It may be related to the downregulation of MMP2 and MMP9 proteins.
Solving Parametric Volterra Integral Equation from Distributed-Order Rough Heston Model and Option Pricing
Authors: Shi Zhengguang
Published: March 2022

The rough Heston model has recently attracted the attention of many financial practitioners and researchers because it maintains the basic structure of the classic Heston model and has an advantage in describing the microstructure foundation of the market. In this paper, we study the distributed-order rough Heston model with an exponential tempered factor, and from the characteristic function of log-price in this model, we obtain a nonlinear parametric Volterra integral equation. Finally, the Fourier-cosine methods are combined with the Adams methods to price the option.
GAXSS: Effective Payload Generation Method to Detect XSS Vulnerabilities Based on Genetic Algorithm
Authors: Liu Zhonglin , Fang Yong , Huang Cheng , Xu Yijia
Published: March 2022

In the fields of social networking, media, and management, web applications on the Internet play a very indispensable role. A large amount of personal privacy information and login tokens make web applications often targeted by hackers. Cross-site scripting attacks are the most common method used to steal data from web applications. To solve the security risks caused by cross-site scripting vulnerabilities, security personnel need to actively discover these vulnerabilities to better defend against the harm. We proposed a novel genetic algorithm-based fuzzing scheme to address this problem. First, a small number of initial attack vectors are generated according to the interactive environment of the web application and then the attack vectors are sequenced into genes. Combined with the grammatical structure features of cross-site scripting and common bypass methods, the gene sequences are iteratively optimized and improved. Finally, the generated high-quality vectors are used to detect potential cross-site scripting threats in the application (we named the implementation of this approach GAXSS). The method we proposed can automatically detect the vulnerability of page interaction points and can obtain better detection results without a large number of test dictionaries, and the time cost is also reasonable. We have conducted vulnerability tests on many common open-source web applications, with a precision rate of 1.0 and an accuracy rate over 0.98. In addition, we also compared GAXSS with other well-known scanners and state-of-the-art detection methods. Its comprehensive performance is better, and it can effectively detect vulnerabilities.
Propofol Upregulates MicroRNA-30b to Inhibit Excessive Autophagy and Apoptosis and Attenuates Ischemia/Reperfusion Injury In Vitro and in Patients
Authors: Lu Zhiqi , Shen Jiaojiao , Chen Xubin , Ruan Zhihua , Cai Weihua , Cai Shuyun , Li Minjun , Yang Yihui , Mo Jian , Mo Guixi , Lu Yan , Tang Jing , Zhang Liangqing
Published: March 2022

Evidence reveals that propofol protects cells via suppressing excessive autophagy induced by hypoxia/reoxygenation (H/R). Previously, we found in a genome-wide microRNA profile analysis that several autophagy-related microRNAs were significantly altered during the process of H/R in the presence or absence of propofol posthypoxia treatment (P-PostH), but how these microRNAs work in P-PostH is still largely unknown. Here, we found that one of these microRNAs, microRNA-30b (miR-30b), in human umbilical vein endothelial cells (HUVECs) was downregulated by H/R treatment but significantly upregulated by 100 M propofol after H/R treatment. miR-30b showed similar changes in open heart surgery patients. By dual-luciferase assay, we found that Beclin-1 is the direct target of miR-30b. This conclusion was also supported by knockdown or overexpression of miR-30b. Further studies showed that miR-30b inhibited H/R-induced autophagy activation. Overexpression or knockdown of miR-30b regulated autophagy-related protein gene expression in vitro. To clarify the specific role of propofol in the inhibition of autophagy and distinguish the induction of autophagy from the damage of autophagy flux, we used bafilomycin A1. LC3-II levels were decreased in the group treated with propofol combined with bafilomycin A1 compared with the group treated with bafilomycin A1 alone after hypoxia and reoxygenation. Moreover, HUVECs transfected with Ad-mCherry-GFP-LC3b confirmed the inhibitory effect of miR-30b on autophagy flux. Finally, we found that miR-30b is able to increase the cellular viability under the H/R condition, partially mimicking the protective effect of propofol which suppressed autophagy via enhancing miR-30b and targeting Beclin-1. Therefore, we concluded that propofol upregulates miR-30b to repress excessive autophagy via targeting Beclin-1 under H/R condition. Thus, our results revealed a novel mechanism of the protective role of propofol during anesthesia. Clinical Trial Registration Number. This trial is registered with ChiCTR-IPR-14005470. The name of the trial register: Propofol Upregulates MicroRNA-30b to Repress Beclin-1 and Inhibits Excessive Autophagy and Apoptosis.