bluuebunny/crossref_metadata_2025 huggingface dataset:
Geometrical and Topological Issues in NMT-Based Modeling
Authors: Saxena Mukul , Srivatsan Rajan , Davis Jonathan E.
Published: March 2021

The Non-Manifold Topology (NMT) Radial Edge data structure, along with the supporting set of Euler operators, provides a versatile environment for modeling non-manifold domains. The operators provide the basic tools to construct and manipulate model topology. However, an implementation of the base functionality in a geometric modeling environment raises some geometry-related issues that need to be addressed to ensure the topological validity of the underlying model. This paper focuses on those issues and emphasizes the use of geometry in the implementation of topological operators. Enhancements to the topology manipulation operations are also discussed. Specifically, this paper describes (i) a geometry-based algorithm for face insertion within the Radial Edge data structure, (ii) a manifestation of the face-insertion algorithm to resolve topological ambiguities that arise in the design of topological glue operators, and (iii) enhancements to the topology deletion operators to meet application-specific requirements.
Object Extent Determination for Algebraic Solid Models
Authors: Ganter M. A. , Storti D. W.
Published: March 2021

This paper presents methods for determination of spatial extent of algebraic solid models. Algebraic solid models (ASM) are a variation of implicit solid models defined by implicit polynomial functions with rational coefficients. Spatial extent information, which can be used to enhance the performance of visualization and property evaluation, includes silhouettes, outlines and profiles. Silhouettes are curves on the surface of the solid which separate portions of the surface which face towards or away from a given viewpoint. The projection of the silhouette onto the viewing plane gives the outline of the solid, and the bivariate implicit function which defines the area enclosed by the outline is called the profile. A method for outline determination is demonstrated using concepts from algebraic geometry including polar surfaces and variable elimination via the Gröbner basis method and/or resultants. Examples of outline generation are presented and a sample profile function is constructed.
Generic Features of the Inverse Kinematics for Control of One Class of Seven-Jointed Robotic Workcells
Authors: Ashton N. S. , Charif M. M. , Davidson J. K.
Published: March 2021

The controllably dexterous capability of a class of seven-jointed serially connected robots is quantitatively confirmed, and the generic features of the inverse kinematics for their control are developed. The generic features are the specific motions of the outermost two joints of the wrist and the aggregates of the motions of the remaining rotary joints in each direction. Of the two global functions among the actuator-coordinates, one is operationally equivalent to a six-jointed substitute-manipulator and the other is a seventh-order polynomial that relates the motion at the last joint of the wrist to the task-motion. The robots in the class can provide a full rotation at constant speed to the end-effector about every task-axis (for a resolution of one degree of angle between adjacent task-axes) through each controllably dexterous fixture-point without encountering the mechanical effects of axis-dependence. For those robots with three P-joints in the arm, this dexterity of motion is accomplished with all joints operating at speeds within 2.0 times the speed of the task rotation. In this paper, the quantitative evaluation is restricted to manipulators with 3R spherical wrists having successively orthogonal axes, the first of which is mounted at right-angles to the adjacent joint-axis in the arm. The CPU-time for executing each computational step is short enough to be useful for on-line operations.
A Novel Theory on Grasping Force Control in a Multifingered Robotic Hand
Authors: Gao Xiaochun , Song Shin-Min
Published: March 2021

Based on inspiration of human grasping activities, a new idea is developed in this paper that grasping forces in a multifingered robotic hand can be regulated and controlled through its compliance by actively coordinating small joint motions in its fingers. According to this idea, a grasping force control model is formulated by means of a compliance model developed by the authors before, and a novel theory is then developed for grasping force control in a multifingered robot hand. The developed theory is expected to lead to a new force control method which could serve as a promising alternative for the active stiffness method. As an application of the developed theory, a two-fingered planar robotic hand is also analyzed, and the simulation results verify the developed theory.
Closed-Form Forward Displacement Analyses of the 4-5 In-Parallel Platforms
Authors: Lin W. , Crane Carl D. , Duffy J.
Published: March 2021

In this paper, we study a class of in-parallel platforms whose six legs are connected either singly or in a pair-wise fashion at the vertices of a quadrilateral top platform and a pentagonal base. A forward displacement analysis in closed-form is performed for each distinct case and polynomials ranging from 16th degree to 32nd degree are derived and verified numerically.
Simplified Mechanism Design
Authors: Jensen Preben W.
Published: March 2021

Mechanisms with one or more degrees of freedom can be developed from kinematic chains and must include open kinematic chains. Open kinematic chains can give greatly simplified solutions to complex problems. One example is described. Kinematic synthesis is another subject, where easy solutions can be obtained using degenerate cases of the Burmester curves. Making the right design assumptions is a third area, where simplifications can be made.
A General Optimization Program for Design of Cam Mechanisms
Authors: Zhao Han , Liang J. , Ma T.
Published: March 2021

This paper presents a compact generalized mathematical model for design of cam mechanisms by using some new geometric and kinematic formulas derived by the authors, and develops a program OPDC that covers more than ten types of planar and spatial cam mechanisms, and by means of which geometric and kinematic analyses as well as design optimization can be performed.
Dynamic Analysis of Mechanisms Using Constrained Lagrangian Bond Graphs
Authors: Khulief Y. A.
Published: March 2021

A method for dynamic analysis of mechanisms using the Lagrangian equations of motion for an interconnected system of rigid bodies is presented. The method stems from a recent extension to the bond graph modeling technique. Intrinsically, this approach allows the formulation of the final form of equations for holonomic systems without recourse to the Lagrangian function. Consequently, the burdens of deriving the expressions for kinetic and potential energies, and performing the necessary differentiations have been eliminated. This method calls only for constructing the Jacobian matrix of constraints, and then employing a bond graph that accounts for the generalized constraint reaction forces.
On Identification and Canonical Numbering of Pin-Jointed Kinematic Chains
Authors: Shin Jae Kyun , Krishnamurty Sundar
Published: March 2021

This paper deals with the development of a standard code for the unique representation of pin-jointed kinematic chains. Salient features of this method, which is based on graph theory, include the development of an efficient and robust algorithm for the identification of isomorphism in kinematic chains; the formulation of a unified procedure for symmetry analysis in kinematic chains; and the utilization of symmetry in the coding process resulting in an unique well arranged numbering of links. This method is not restricted to simple jointed kinematic chains only, and it can be applied to any kinematic chain which can be represented as simple graphs including open jointed and multiple jointed chains. In addition, the method is decodable as the original chain can be reconstructed unambiguously from the code values associated with those chains.
On the Nomenclature and Classification of Compliant Mechanisms: The Components of Mechanisms
Authors: Midha Ashok , Norton Tony W. , Howell Larry L.
Published: March 2021

Compliant mechanisms gain some or all of their mobility from the flexibility of their members rather than from rigid-body joints only. Compliant mechanisms are desirable since they require fewer parts, and have less wear, noise, and backlash than their rigid-body counterpart mechanisms. The field of compliant mechanisms is important, and is expected to continue to grow as materials with superior properties are developed. Inasmuch as evolution of efficient design techniques is viewed as essential research activity, a parallel, systematic development of appropriate vocabulary (nomenclature, classification, etc.) is of primary importance. This paper proposes standard nomenclature for the components of compliant mechanisms and discusses the relevant issues involved in this process. Definitions for components, such as “links” and “joints,” remove ambiguity that has been associated with these terms in the past. A concerted effort is made to be consistent with current literature on both rigid-body mechanisms and compliant mechanisms whenever possible.
Kinematic Analysis and Synthesis of Three-Input, Eight-Bar Mechanisms Driven by Relatively Small Cranks
Authors: Farhang Kambiz , Basu Partha Sarathi
Published: March 2021

Approximate kinematic equations are developed for the analysis and design of three-input, eight-bar mechanisms driven by relatively small cranks. Application of a method in which an output link is presumed to be comprised of a mean and a perturbational motions, along with the vector loop approach facilitates the derivation of the approximate kinematic equations. The resulting constraint equations are, (i) in the form of a set of four nonlinear equations relating the mean link orientations, and (ii) a set of four linear equations in the unknown perturbations (output link motions). The latter set of equations is solved, symbolically, to obtain the output link motions. The approximate equations are shown to be effective in the synthesis of three-input, small-crank mechanisms.
Modeling of Multibody Flexible Articulated Structures With Mutually Coupled Motions: Part I — General Theory
Authors: Xu Jiechi , Baumgarten Joseph R.
Published: March 2021

In the present paper a general systematic modeling procedure has been conducted in deriving dynamic equations of motion using Lagrange’s approach for a spatial multibody structural system involving rigid bodies and elastic members. Both the rigid body degrees of freedom and the elastic degrees of freedom are considered as unknown generalized coordinates of the entire system in order to reflect the nature of mutually coupled rigid body and elastic motions. The assumption of specified rigid body gross motion is no longer necessary in the equation derivation and the resulting differential equations are highly nonlinear. Finite element analysis (FEA) with direct stiffness method has been employed to model the flexible substructures. Nonlinear coupling terms between the rigid body and elastic motions are fully derived and are explicitly expressed in matrix form. The equations of motion of each individual subsystem are formulated based on a moving frame instead of a traditional inertial frame. These local level equations of motion are assembled to obtain the system equations with the implementation of geometric boundary conditions by means of a compatibility matrix.
Uses of Object-Oriented Techniques in CAD/CAM Development
Authors: Lewis C. Richard
Published: March 2021

Object-oriented techniques are increasingly regarded as important in the development of computer software products. The consensus is usually that deployment of these techniques lies somewhere in the future. This article points out the uses of object-oriented techniques that have existed for more than 25 years in CAD/CAM systems, although not generally referred to in such terms, and future uses that are crucial to advanced development.
Helminths from the red-eared slider Trachemys scripta elegans (Chelonia: Emydidae) in marshes from the eastern Iberian Peninsula: first report of Telorchis attenuata (Digenea: Telorchiidae)
Authors: Cardells Jesús , Garijo María Magdalena , Marín Clara , Vera Santiago
Published: March 2021

The present work describes the presence of a digenean in the red-eared turtle Trachemys scripta elegans (Wied-Neuwied, 1839) in marshes of the Valencian Community. The faeces and intestinal tract of 105 animals were examined. Only one helminth species was found and identified as the digenean trematode Telorchis atenuatta (Goldberger, 1911), present in the 7.6% of the animals analysed. This is the first report of the parasite in sliders from Spain. Although conclusions are preliminary due to the limited sampling, our results suggest that the presence of red-eared turtles in new habitats may increase the risk of introducing new microorganisms and new diseases with them, altering the sanitary status of the autochthonous terrapins Mauremys leprosa (Schweigger, 1812) and Emys orbicularis (Linnaeus, 1758).
Lens array captures dim objects missed by giant telescopes
Authors: Schilling Govert
Published: March 2021

Upgraded Dragonfly will study how dark matter shapes diffuse galaxies and faint tendrils of gas
The emerging plasticity of SARS-CoV-2
Authors: McCormick Kevin D. , Jacobs Jana L. , Mellors John W.
Published: March 2021

The evolution of SARS-CoV-2 poses challenges for vaccines and immunotherapies
The conservationists
Beloved Beasts: Fighting for Life in an Age of Extinction
Michelle Nijhuis
Norton, 2021. 352 pp.
Authors: Kemp Christopher
Published: March 2021

Passionate advocates have helped humanity rethink its relationship with Earth's other species
A planet remade in our image
Second Nature: Scenes from a World Remade
Nathaniel Rich
Farrar, Straus and Giroux, 2021. 304 pp.
Authors: Hannibal Mary Ellen
Published: March 2021

As Anthropocene impacts accumulate, a sometimes-unrecognizable Earth emerges
Catching the wave
Authors: Hambleton Sophie
Published: March 2021

Uncoupling metabolism from cytoskeletal regulation leads to T cell dysfunction
Gold meets peptides in a hybrid coil
Authors: Nam Ki Tae , Kim Hyeohn
Published: March 2021

Twisted structures are assembled cooperatively by β-sheet peptides and gold nanorods
Volatility of vaccine confidence
Authors: Larson Heidi J. , Broniatowski David A.
Published: March 2021

Last week, the European Medicines Agency declared the AstraZeneca COVID-19 vaccine safe and effective, after several European Union member states had suspended its use because of blood clot concerns. Will the public trust this message? This week's news could help—a U.S. phase 3 clinical trial of the vaccine shows promising efficacy in preventing symptomatic COVID-19. But sentiments toward vaccines are volatile and reflect external events—such as recent concern about AstraZeneca's efficacy data—as well as internal emotions.
Comparative Performance of Latest-Generation and FDA-Cleared Serology Tests for the Diagnosis of Chagas Disease
Authors: Kelly Emily A. , Bulman Christina A. , Gunderson Emma L. , Irish Amanda M. , Townsend Rebecca L. , Sakanari Judy A. , Stramer Susan L. , Bern Caryn , Whitman Jeffrey D.
Published: March 2021

Confirmed diagnosis of chronic Chagas disease (CD) requires positive results by two different IgG serology tests. Variable sensitivity has been reported among tests and in different regions of endemicity.
Health condition at first fit note and number of fit notes: a longitudinal study of primary care records in south London
Authors: Dorrington Sarah , Carr Ewan , Polling C , Stevelink Sharon , Ashworth Mark , Roberts Emmert , Broadbent Matthew , Hatch Stephani , Madan Ira , Hotopf Matthew
Published: March 2021

Objectives

The fit note replaced the sick note in the UK in 2010, with the aim of improving support for patients requiring sickness absence, yet there has been very little research into fit note use. This study aims to describe number of fit notes by condition, to improve our understanding of patterns of fit note use in primary care. Previous fit note research has relied on extracting diagnoses directly from fit notes, rather than extracting information from clinical records. In this paper, we extract information from clinical records to explore demographic factors and conditions associated with number of fit notes issued.

Design

This is a longitudinal study of clinical data. We analysed individual-level anonymised data from general practitioner consultations, including demographic information and condition recorded at first fit note. The latter encompassed diagnoses, individual symptoms and psychosocial issues.

Setting

A database called Lambeth DataNet, containing electronic clinical records on 326 415 adults (ages 16–60) from all 45 general practices within the London Borough of Lambeth from 1 January 2014 to 30 April 2017.

Participants

Our analytical sample contained 40 698 people with a condition recorded at first fit note.

Primary outcome measure

Predicted number of fit notes in the period January 2014–April 2017

Results

Of all studied diagnostic groups, mental illness had the highest predicted number of fit notes (n=3.3; 95% CI: 3.1 to 3.4) after controlling for demographic factors and long-term conditions. The highest predicted number of fit notes for any condition subgroup was among patients presenting for drug and/or alcohol misuse (n=4.5; 95% CI: 4.1 to 4.8).

Conclusions

For the first time, we show drug and/or alcohol misuse at first fit note are associated with the highest number of fit notes. Research is needed to understand the trajectories of individuals at highest risk of long-term sickness absence, in particular, people presenting with drug and/or alcohol misuse.
How can a coordinated regional smoking cessation initiative be developed and implemented? A programme logic model to evaluate the ‘10,000 Lives’ health promotion initiative in Central Queensland, Australia
Authors: Khan Arifuzzaman , Green Kalie , Khandaker Gulam , Lawler Sheleigh , Gartner Coral
Published: March 2021

Objective

This study used a programme logic model to describe the inputs, activities and outputs of the ‘10,000 Lives’ smoking cessation initiative in Central Queensland, Australia.

Design

A programme logic model provided the framework for the process evaluation of ‘10,000 Lives’. The data were collected through document review, observation and key informant interviews and subsequently analysed after coding and recoding into classified themes, inputs, activities and outputs.

Setting

The prevalence of smoking is higher in the Central Queensland region of Australia compared with the national and state averages. In 2017, Central Queensland Hospital and Health Services set a target to reduce the percentage of adults who smoke from 16.7% to 9.5% in the Central Queensland region by 2030 as part of their strategic vision (‘Destination 2030’). Achieving this target is equivalent to 20,000 fewer smokers in Central Queensland, which should result in 10,000 fewer premature deaths due to smoking-related diseases. To translate this strategic goal into an actionable smoking cessation initiative, the ‘10,000 Lives’ health promotion programme was officially launched on 1 November 2017.

Result

The activities of the initiative coordinated by a senior project officer included building clinical and community taskforces, organising summits and workshops, and regular communications to stakeholders. Public communication strategies (e.g., Facebook, radio, community exhibitions of ‘10,000 Lives’ and health-related events) were used to promote available smoking cessation support to the Central Queensland community.

Conclusion

The ‘10,000 Lives’ initiative provides an example of a coordinated health promotion programme to increase smoking cessation in a regional area through harnessing existing resources and strategic partnerships (e.g., Quitline). Documenting and describing the process evaluation of the ‘10,000 Lives’ model is important so that it can be replicated in other regional areas with high prevalence of smoking.
Determining the effects of transcranial direct current stimulation on tinnitus and tinnitus-related outcomes: protocol for a systematic review
Authors: Labree Bas , Hoare Derek J , Gascoyne Lauren E , Sereda Magdalena
Published: March 2021

Introduction

Tinnitus is the awareness of a sound in the ear or head in the absence of an external source. It affects around 10%–15% of people. About 20% of people with tinnitus also experience symptoms such as depression or anxiety that negatively affect their life. Transcranial direct current stimulation (tDCS) is a technique involving constant low-intensity direct current delivered via electrodes on the head. It is postulated to modulate (suppress or enhance) neural activity in the region between electrodes. As such, it represents a potential treatment option for tinnitus, as well as comorbid depression or anxiety. This systematic review will estimate the effects of tDCS on outcomes relevant to tinnitus. In addition, it will determine whether there is any relationship between stimulation parameters (electrode montage, current intensity, and length and frequency of stimulation sessions) and the effect of tDCS on these outcomes.

Methods and analysis

Electronic searches for peer-reviewed journal articles will be performed in the Cochrane Register of Studies online (the Cochrane Ear, Nose and Throat Disorders Group Register and CENTRAL, current issue), PubMed, EMBASE, CINAHL, LILACS, KoreaMed, IndMed, PakMediNet, CNKI, AMED, PsycINFO, Web of Science, ClinicalTrials.gov, ICTRP and Google Scholar using the following search terms: transcranial Direct Current Stimulation OR tDCS AND tinnitus OR depression OR anxiety OR quality of life OR adverse effects OR neurophys*.

Searches were not limited by date. Methods are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P). Randomised controlled trials will be included if they report at least one of the following outcomes: tinnitus symptom severity, anxiety or depression as measured by relevant validated instruments. Where available, data on quality of life, adverse effects and neurophysiological changes will also be reviewed. In addition to an analysis of the effect of each parameter, an analysis will be performed to uncover any interactions between parameters. Where appropriate, meta‐analyses will be performed.

Ethics and dissemination

This systematic review will make use of secondary data only. As no data will be obtained from participants directly, ethical approval has not been sought. No other ethical issues are foreseen. Findings will be submitted for peer-reviewed publication and presented at academic conferences. The results of this review will inform future research.

PROSPERO registration number

CRD42020185567.
The limits of our knowledge: tracking the size and scope of police involvement with persons with mental illness
Authors: Huey Laura , Ferguson Lorna , Vaughan Adam D.
Published: March 2021

Significant public discourse has focused recently on police–civilian interactions involving with persons with mental illness (PMI). Despite increasing public attention, and growing demands for policy change, little is actually known about the myriad of ways in which Canadian police encounter PMI in the context of routine police work. To assist policymakers in developing evidence-informed policy, this paper attempts to shed light on present difficulties associated with addressing fundamental questions, such as the prevalence of mental health related issues in police calls for service. To do this, we attempt to map the size and scope of police calls for service involving PMI, drawing on both the available scientific data and the limited knowledge to be gleaned from available police reports. Our focus is on two broad categories of police interactions with citizens: public safety concerns (wellness checks, suicide threats, missing persons, mental health apprehensions) and crime prevention and response (encountering PMI as victims–complainants and (or) as potential suspects). We also explore the challenges policy-makers face in relying on police data and the importance of overcoming weaknesses in data collection and sharing in relation to the policing of uniquely vulnerable groups. This paper concludes with some key recommendations for addressing gaps highlighted.
Investigation on the aerodynamic interaction between a rotor and ship with opened hangar door
Authors: Wang Chang , Ma Shuai , Liu Qing Ling , Yue Ting Rui , Tan Jianfeng , Wang Haowen
Published: March 2021

Unsteady aerodynamic interference between a rotorcraft and a ship occurs during shipboard launch and recovery operations and has a negative impact on the safety. An experiment of a reduced-scale model rotor and a CFD analysis in hover was carried out to investigate the performance and flow field of a rotor approaching a ship. In this paper, the thrust and pitching moment of the rotor hovering above the ground, deck were tested, and the influence of hangar door on the thrust, pitching moment, and flow field was also measured. A CFD method based on RANS and overset technology was used to investigate the flow field of the rotor operating on the model-scale ship. As the rotor approaches the deck, its thrust first decreases induced by a recirculation near the deck, and then increases induced by the effect of deck, and finally obviously decreases caused by the recirculation near hangar door. The deck and hangar door also affects the flow field to yield an intensive nose-down pitching moment. The status of the hangar door has a significant influence on the rotor thrust and pitching moment. The recirculation is weakened with an opened hangar door resulting in recovery of the rotor thrust and decrease of the nosed down pitching moment.
Trade Credit and Capital Structure Adjustment Speed: Evidence From Chinese Listed Firms
Authors: Cao Jifeng , Cui Yiwen
Published: March 2021

This paper examines the impact of trade credit on the speed of capital structure adjustment toward target leverage using an integrated dynamic partial adjustment model. Trade credit is an important substitute for debt financing and gives firms a low-cost means of adjusting leverage toward the target capital structure in China. We measure trade credit by accounts payable. Using the public listed company data from 1998 to 2016, we find that trade credit accelerates capital structure adjustment. The asymmetric impacts on the capital structure adjustment speed in different situations are also evidenced. The positive impact of trade credit on the speed of capital structure adjustment is more pronounced for over-levered firms. The trade credit also accelerates the speed of capital structure adjustment more quickly for high market share firms. Our results imply that firms use trade credit to save cash flow and restore the leverage level to the target capital structure in China.
HISTOPATHOLOGICAL AND BIOMECHANICAL INVESTIGATION OF THE EFFECT OF MOMORDICA CHARANTIA ON FRACTURE HEALING, KIDNEY, AND LIVER: AN EXPERIMENTAL RAT MODEL
Authors: OZTURK BURHAN , INAL SERMET , DULGEROGLU T. CIHAN , UZUMCUGIL A. OKTAR , DEGER AYSENUR , KUYUBASI S. NUMAN , KARAYEL H. BASRI , GOK KADIR
Published: March 2021

Momordica charantia (MC) is a plant belonging to the family Cucurbitaceae. MC has antidiabetic, antibacterial, antioxidant, antimutagenic, antiulcerative, antiinflammatory and antilipidemic effects. However, information on the effect of MC on fracture union is lacking. This study aimed to examine the effect of MC on fracture union histopathologically and biomechanically. A total of 42 male Wistar-Albino rats were randomly divided into 3 groups, 14 in each group. A diaphyseal fracture was created on the right tibia of all rats. All fractures were fixed with a Kirschner (K) wire. The rats in Group I did not undergo any further procedures (Control group). Group II rats were treated with 0.9% saline oral gavage at a dose of [Formula: see text]L/day for 28 days [Saline (S) group]. The rats in Group III were given 300[Formula: see text]mg/kg MC extract per day, dissolved in [Formula: see text]L 0.9% saline by oral gavage for 28 days [MC (Extract) group]. After 28 days, all rats were sacrificed. Each group was randomly divided into two subgroups. The histopathological examination was performed on the right tibia of rats in the first subgroup and the biomechanical examination in the second subgroup. The kidneys and livers of all rats were evaluated histopathologically. Fracture union was significantly better in the Extract group compared with the Control and S groups histopathologically. The fracture inflammation values were lower in the Extract group than in the other groups. No statistically significant difference was found between the groups in terms of possible side effects to kidneys and livers. In terms of biomechanics, fracture union was significantly better in the Extract group compared with the Control and S groups except yield displacement values. MC had a positive effect on fracture union histopathologically and biomechanically.
Impacts of a Bathing Space on the Lives of the Rural Women in India
Authors: PAWAR VAISHNAVI
Published: March 2021

According to the 2011 Census of India, around 55% of rural households do not access a private bathing facility. The research study examines whether a bathing space’s presence improves the quality of life of the women using it. The study was conducted in two Indian states, Madhya Pradesh and West Bengal, where two private agencies had facilitated bathing spaces. 54 women were interviewed for the purpose of the study. Individual interviews were conducted to understand the perception of the women who had recent access to the bathing spaces. The research shows that women who have access to bathing space have perceived positive changes in their health. Because of access to a private and secluded area, they can carry out Menstrual Hygiene Management practices. Along with the health benefits, the women participants also perceived changes in their daily lives. While there were numerous benefits of the bathing space, the burden of filling water and maintaining the bathing spaces on women increased. The paper also tries to understand what are the reasons for not constructing a bathing space. Cultural norms, lack of land, lack of water and water connectivity, lack of awareness, and economic reasons came across as reasons for not constructing a bathing space in the study.
Ion Channel Degeneracy, Variability, and Covariation in Neuron and Circuit Resilience
Authors: Goaillard Jean-Marc , Marder Eve
Published: March 2021

The large number of ion channels found in all nervous systems poses fundamental questions concerning how the characteristic intrinsic properties of single neurons are determined by the specific subsets of channels they express. All neurons display many different ion channels with overlapping voltage- and time-dependent properties. We speculate that these overlapping properties promote resilience in neuronal function. Individual neurons of the same cell type show variability in ion channel conductance densities even though they can generate reliable and similar behavior. This complicates a simple assignment of function to any conductance and is associated with variable responses of neurons of the same cell type to perturbations, deletions, and pharmacological manipulation. Ion channel genes often show strong positively correlated expression, which may result from the molecular and developmental rules that determine which ion channels are expressed in a given cell type.
Molten Salt Assisted Low-Temperature Electro-Catalytic Graphitization of Coal Chars
Authors: Thapaliya Bishnu P. , Luo Huimin , Li Mengya , Tsai Wan-Yu , Meyer Harry M. , Dunlap John R. , Nanda Jagjit , Belharouak Ilias , Dai Sheng
Published: March 2021

A great effort has been centered around developing clean energy technologies (energy storage devices) to curtail burning fossil fuels’ deleterious environmental effects. Rechargeable batteries [lithium-ion batteries (LIBs)] are among the most invested and investigated storage devices showing potential to transform fossil fuel-powered mobility to next-generation safe electromobility. However, LIBs powered electric vehicles (EV) are expensive due to the high-cost graphite anode associated with LIBs. Herein, the synthesis of low-cost, highly crystalline nano-graphite with a tunable microstructural architecture has been demonstrated via molten salt assisted low-temperature electro-catalytic graphitization of coal chars, traditionally non-graphitizable carbon. Thus, graphite derived from coal chars exhibited nanoflake architecture and delivered high reversible capacity, stable long cycle life, and excellent electrochemical performance under fast charging/discharging conditions (5C, ∼12 min charge/discharge time). This finding paves the way to manufacture cost-effective high-energy-density batteries using as-synthesized graphite from readily available coal sources that could propel the EVs to the next level.
Impact of COVID-19 on exercise pathophysiology: a combined cardiopulmonary and echocardiographic exercise study
Authors: Baratto Claudia , Caravita Sergio , Faini Andrea , Perego Giovanni Battista , Senni Michele , Badano Luigi P. , Parati Gianfranco
Published: March 2021

At the time of hospital discharge, patients with COVID-19 present with reduced functional capacity and exercise hyperventilation. Peripheral factors, namely reduced oxygen extraction (myopathy) and anemia, which are not fully compensated by a supernormal cardiac output response, account for exercise limitation before exhaustion of the respiratory reserve. Enhanced chemoreflex sensitivity, rather increased dead space, mainly accounts for exercise hyperventilation. The pulmonary vascular response to exercise circulation of survived patients with COVID-19 does not present major pathological changes.
Theoretical Study and Numerical Simulation Research on the Effect of Coal‐Rock Interface on Multistaged Fracturing in the Roof of Outburst Coal Seam
Authors: Zhang Fan , Tang Yang
Published: March 2021

Multistaged fracturing in the roof of outburst coal seam is an efficient and creative technology for coalbed methane (CBM) drainage, which can effectively improve the permeability of coal seam. To reveal its mechanism of permeability enhancement, the effect of coal‐rock interface on multistaged fracturing in the roof of outburst coal seam was simulated and discussed in this paper. Firstly, the lithological difference between outburst coal seam and roof was compared, and the concept and significance of multistaged fracturing in the roof of outburst coal seam were explained. Then, the mechanical conditions of multiple fractures in the roof traversing coal‐rock interface were analyzed. The effects of mechanical parameters on multiple fractures were numerically simulated. The results indicated that fracturing borehole in adjacent rocks of outburst coal seam is much easier to drill and maintain gas drainage. Considering gas drainage efficiency and avoiding being blocked by coal fines, multistaged fracturing borehole is generally drilled in the stable rock stratum of roof. Whether the multiple fractures in the roof can traverse coal‐rock interface is related to mechanical parameters of coal and rock, friction factor of coal‐rock interface, angle between horizontal profile and coal‐rock interface, cementing strength of coal‐rock interface, minimum horizontal stress, and other factors. Higher fracturing fluid pressure contributes to propagating from the reservoir with low elastic modulus to the one with high elastic modulus for hydraulic fracture. Hydraulic fracture is more likely to propagate in the rock stratum with high brittleness index. The research results can improve multistaged fracturing theory and provide technological support for field test.
A Novel Smith Predictive Linear Active Disturbance Rejection Control Strategy for the First-Order Time-Delay Inertial System
Authors: Chen Guangda , Liu Dejun , Mu Yongxin , Xu Jinfei , Cheng Yanming
Published: March 2021

The control strategy research of the time-delay system is a focused issue in the control field. In order to furthermore improve the performance of the first-order time-delay inertial system, firstly, a new Smith predictor structure is proposed, which solves the constraint that the conventional Smith predictor needs to match the actual object model. Secondly, the performance and parameter function of the new Smith predictor are discussed in theory to provide the basis for parameter tuning. Finally, a new Smith predictor combined with linear active disturbance rejection control (LADRC) is proposed to solve the problem that the two input signals of the linear extended state observer (LESO) are not synchronized on the time scale, and the stability of the new Smith + LADRC time-delay control system is proved theoretically for known and unknown controlled complex objects. Simulation analysis is conducted to verify the robustness of the proposed strategy under the condition of the different parameters. The results indicate that the proposed strategy has better performance than the conventional method in response speed, overshoot, adjustment time, and stability.
Small-Scale Diagenetic Heterogeneity Effects on Reservoir Quality of Deep Sandstones: A Case Study from the Lower Jurassic Ahe Formation, Eastern Kuqa Depression
Authors: Zhang LiKuan , Luo Xiaorong , Ye Mingze , Zhang Baoshou , Wei Hongxing , Cao Binfeng , Xu Xiaotong , Liu Zhida , Lei Yuhong , Li Chao
Published: March 2021

The Lower Jurassic Ahe Formation is an important exploration target for deep clastic reservoirs in the eastern Kuqa Depression. The Ahe Formation sandstones show heterogeneous porosity and permeability petrophysical properties. These properties have been poorly understood, limiting forecast of petroleum accumulations and making it difficult to develop the reservoirs. Based on cores, thin sections, SEM, and fluid inclusions, this study examined sandstone composition and texture and diagenetic heterogeneity at the core scale. The aim was to understand the influence of variations in detrital composition and texture on diagenetic and reservoir quality evolution. The Ahe Formation sandstones are dominantly fine- to coarse-grained litharenites, with minor feldspathic litharenites. In fining-up sand beds, detrital grain size determines the degree of mechanical compaction and, consequently, the abundance of porosity through ductile grains and muddy matrix. Local complete calcite cementation is a noticeable exception to this general trend. Three sandstone petrofacies have been defined based on texture and framework composition, detrital matrix, diagenesis, and pore types: (1) ductile-lean sandstone, (2) ductile-rich sandstone, and (3) tightly calcite-cemented sandstone. Different petrofacies experienced contrasting diagenetic and porosity evolution pathways. Ductile-lean sandstones underwent lower degree of compaction relative to ductile-rich sandstones during the eodiagenesis stage, and extensive grain dissolution occurred. The petrofacies remained relatively porous and permeable before early oil arrival. With continued burial, the porosity and permeability in the sandstones were further reduced by cementation. The petrofacies still had moderate porosity and permeability and were substantially charged when late petroleum migrated into the reservoirs. Thus, ductile-lean sandstones constitute effective reservoir rocks in deep reservoirs. By translating petrofacies to signatures of well logs, the effective properties of the reservoir rocks can be forecasted at the well scale.
Investigation of Water Leakage of Metro Segments Caused by Metro Underpass Structures
Authors: Liang Xiao , Qi Taiyue , Jin Zhiyi , Chen Pengtao , Lei Bo , Qian Wangping , Wang Xianyu
Published: March 2021

Water leaking into metro segments is related directly to the presence of underground water. However, to date, the underground confined water channels formed by metro underpass reinforcement structures have not been considered as causes of the problem. In the present study, based on field investigations and geological data, confined water is identified as the source of segment leakage on Line 5 of Hangzhou Metro in China. It is then hypothesized that the problem stems from an underground confined water channel formed under the reinforced structure of the subway. Numerical simulations predict a settlement difference of 8–10 mm between the reinforcement area and the weak strata, and field monitoring data show this difference to be 8.62 mm. This consistency between the numerical simulations and the field measurements verifies the hypothesis. Finally, given the causes of underground confined water channels, corresponding technical measures such as piecewise secondary grouting are proposed to cut them off and avoid metro‐segment leakage. The present research results contribute to the causes of and the laws governing the metro‐segment leakage that occurs at subway stations and other reinforced structures.
On the Stabilization and Observer Design of Polytopic Perturbed Linear Fractional-Order Systems
Authors: Naifar Omar , Ben Makhlouf Abdellatif
Published: March 2021

In this paper, the problem of stabilization and observer design of parameter-dependent perturbed fractional-order systems is investigated. Sufficient conditions on the practical Mittag–Leffler and Mittag–Leffler stability are given based on the Lyapunov technique. Firstly, the problem of stabilization using the state feedback is developed. Secondly, under some sufficient hypotheses, an observer design which provides an estimation of the state is constructed. Finally, numerical examples are provided to validate the contributed results.
A Meta-Analysis of a Cohort Study on the Association between Sleep Duration and Type 2 Diabetes Mellitus
Authors: Lu Huapeng , Yang Qinling , Tian Fang , Lyu Yi , He Hairong , Xin Xia , Zheng Xuemei
Published: March 2021

Objective. To study the association between sleep duration and the incidence of type 2 diabetes mellitus (T2DM) and to provide a theoretical basis for the prevention of T2DM through a meta-analysis. Methods. PubMed, Web of Science, Scopus, Embase, Cochrane Library, ProQuest, CNKI, Wanfang, VIP, and SINOMED were searched from their inception until May 2020. All cohort studies on the relationship between sleep duration and T2DM in adults were included. According to the inclusion and exclusion criteria, two authors independently assessed the literature and extracted the data. Metaregression and publication bias were evaluated, and sensitivity and meta-analyses were conducted with RevMan 5.3. Results. A total of 17 studies were collected, involving 737002 adults. The incidence of T2DM was 4.73% in short sleep duration (SSD) (t≤6 h), 4.39% in normal sleep duration (NSD) (6 h<t<9 h), and 4.99% in long sleep duration (LSD) (t≥9 h). The meta-analysis demonstrated that SSD increased the risk of T2DM compared with NSD (RR=1.22, 95% CI: 1.15-1.29,P<0.001), LSD increased the risk of T2DM compared with NSD (RR=1.26, 95% CI: 1.15-1.39,P<0.001), and the risk of T2DM has no significant difference between SSD and LSD (RR=0.97, 95% CI: 0.89-1.05,P=0.41). The sensitivity of each study was robust and the publication bias was weak. Conclusion. SSD or LSD can increase the risk of T2DM.
Serum Levels of Androgens, Estrogens, and Sex Hormone Binding Globulin and Risk of Primary Gastric Cancer in Chinese Men: A Nested Case–Control Study
Authors: Zhu Zhikai , Chen Yingxi , Ren Jiansong , Dawsey Sanford M. , Yin Jian , Freedman Neal D. , Fan Jin-Hu , Taylor Philip R. , Liu Yuanli , Qiao You-Lin , Abnet Christian C.
Published: March 2021

Gastric cancer shows a strong male predominance, and sex steroid hormones have been hypothesized to explain this sex disparity. Previous studies examining the associations between sex hormones and sex hormone binding globulin (SHBG) and risk of gastric cancer come primarily from western populations and additional studies in diverse populations will help us better understand the association. We performed a nested case–control study in Linxian Nutrition Intervention Trials cohorts to evaluate the associations among Chinese men, where we had sufficient cases to perform a well-powered study. Using radioimmunoassays and immunoassays, we quantitated androgens, estrogens, and SHBG in baseline serum from 328 men that developed noncardia gastric cancer and matched controls. We used multivariable unconditional logistic regression to calculate ORs and 95% confidence intervals (CI) and explored interactions with body mass index (BMI), age, alcohol drinking, smoking, and follow-up time. Subjects with SHBG in the highest quartile, as compared with those in the lowest quartile, had a significantly increased risk of gastric cancer (OR = 1.87; 95% CI, 1.01–3.44). We found some evidence for associations of sex steroid hormones in men with lower BMI. Our study found a novel association suggesting that higher serum concentrations of SHBG may be associated with risk of gastric cancer in men. We found no overall associations with sex hormones themselves, but future studies should expand the scope of these studies to include women and further explore whether BMI modifies a potential association.

Prevention Relevance:

It was the first study to investigate the association of gastric cancer with prediagnostic sex steroid hormones and SHBG in an Asian male population. Although there were no overall associations for sex steroid hormone concentrations, higher concentrations of SHBG was associated with increased risk of noncardia gastric cancer.
Inducible Depletion of Calpain-2 Mitigates Abdominal Aortic Aneurysm in Mice
Authors: Muniappan Latha , Okuyama Michihiro , Javidan Aida , Thiagarajan Devi , Jiang Weihua , Moorleghen Jessica J. , Yang Lihua , Balakrishnan Anju , Howatt Deborah A. , Uchida Haruhito A. , Saido Takaomi C. , Subramanian Venkateswaran
Published: March 2021

Objective:

Cytoskeletal structural proteins maintain cell structural integrity by bridging extracellular matrix with contractile filaments. During abdominal aortic aneurysm (AAA) development, (1) aortic medial degeneration is associated with loss of smooth muscle cell integrity and (2) fibrogenic mesenchymal cells mediate extracellular matrix remodeling. Calpains cleave cytoskeletal proteins that maintain cell structural integrity. Pharmacological inhibition of calpains exert beneficial effects on Ang II (angiotensin II)–induced AAAs in LDLR
−/−
(low-density receptor deficient) mice. Here, we evaluated the functional contribution of fibrogenic mesenchymal cells-derived calpain-2 on (1) cytoskeletal structural protein and extracellular matrix alterations and (2) AAA progression.

Approach and Results:

Calpain-2 protein and cytoskeletal protein (filamin and talin) fragmentation are significantly elevated in human and Ang II–induced AAAs in mice. To examine the relative contribution of calpain-2 in AAA development, calpain-2 floxed mice in an LDLR
−/−
background were bred to mice with a tamoxifen-inducible form of Cre under control of either the ubiquitous promoter, chicken β-actin, or fibrogenic mesenchymal cell-specific promoter, Col1α2 (collagen type 1 alpha 2). Ubiquitous or fibrogenic mesenchymal cell-specific depletion of calpain-2 in mice suppressed Ang II–induced AAAs, filamin/talin fragmentation, while promoting extracellular matrix protein, collagen in the aortas. Calpain-2 silencing in aortic smooth muscle cells or fibroblasts reduced Ang II–induced filamin fragmentation. In addition, silencing of filamin in aortic SMCs significantly reduced collagen protein. Furthermore, calpain-2 deficiency suppressed rupture of established Ang II–induced AAAs in mice.

Conclusions:

Our studies implicate that calpain-2 deficiency prevents (1) Ang II–induced cytoskeletal structural protein fragmentation and AAA development and (2) stabilize and suppress rupture of established AAAs in mice.