bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversification along a benthic to pelagic gradient contributes to fish diversity in the world's largest lake (Lake Baikal, Russia)
Authors: St. John Carl A. , Buser Thaddaeus J. , Kee Victoria E. , Kirilchik Sergei , Bogdanov Bakhtiar , Neely David , Sandel Michael , Aguilar Andres
Published: October 2021

Insights into the generation of diversity in both plants and animals have relied heavily on studying speciation in adaptive radiations. Russia's Lake Baikal has facilitated a putative adaptive radiation of cottid fishes (sculpins), some of which are highly specialized to inhabit novel niches created by the lake's unique geology and ecology. Here, we test evolutionary relationships and novel morphological adaptation in a piece of this radiation: the Baikal cottid genus,Cottocomephorus, a morphologically derived benthopelagic genus of three described species. We used a combination of mitochondrial DNA and restriction site associated DNA sequencing from allCottocomephorusspecies. Analysis of mitochondrial cytochrome b haplotypes was only able to two resolve two lineages:C. grewingkiiandC. comephoroides/inermis. Phylogenetic inference, principal component analysis, andfaststructureof genome‐wide SNPs uncovered three lineages withinCottocomephorus:C. comephoroides,C. inermisandC. grewingkii. We found recent divergence and admixture betweenC. comephoroidesandC. inermisand deep divergence between these two species andC. grewingkii. Contrasting other fish radiations, we found no evidence of ancient hybridization amongCottocomephorusspecies. Digital morphology revealed highly derived pelagic phenotypes that reflect divergence by specialization to the benthopelagic niche inCottocomephorus. AmongCottocomephorusspecies, we found evidence of ongoing adaptation to the pelagic zone. This pattern highlights the importance of speciation along a benthic‐pelagic gradient seen inCottocomephorusand across other adaptive fish radiations.
Relationships, continuity and time in health professions education
Authors: Ross Shelley , Lee Ann S.
Published: October 2021

Ross & Lee discuss evolution of teacher‐learner relationships from hierarchical to collegial, arguing that shared experiences over time may be the “secret sauce” to engagement in bidirectional learning.
Understanding moral empathy: A verbatim‐theatre supported phenomenological exploration of the empathy imperative
Authors: Pieris Dilshan , Jafine Hartley , Neilson Shane , Amster Ellen , Zazulak Joyce , Lam Connie , Grierson Lawrence
Published: October 2021

Objectives

Several studies have measured a decline in empathy during medical training, speculating that factors within the formal, informal and hidden curricula are responsible for this phenomenon. Although the medical education literature describes the moral domain of empathy as most fundamental to the empathic response, most research into the decline has examined the cognitive, affective and behavioural domains. This study distinguishes itself by focusing on how moral empathy is affected through training.

Methods

Ten medical residents from core education specialties at McMaster University participated in lightly structured interviews concerning their training experiences. Interview transcripts were analysed by way of a descriptive phenomenological approach. Analyses afforded descriptions of the way medical training influences moral empathy. These descriptions were then used to generate a verbatim theatre play that was performed for an audience of residents, educators, learners, researchers and scholars. Following the play, audience participants completed a survey to member‐check the descriptions and to glean other reflective experiences in resident training that impact moral empathy. The survey results informed revisions to the codebook that was subsequently used to re‐analyse the interview transcripts. This resulted in a final, refined version of the influence of training on learner moral empathy.

Results

The findings suggest that a resident's sense of moral empathy relies upon the notion of an innate capacity for empathy, and is influenced by their clinical and classroom education, and specific experiences with patients during training. Importantly, these factors are rarely experienced as having a direct deleterious impact on residents' moral empathy but rather are experienced as challenges to their ability to act on their moral empathy.

Conclusions

The study promotes reflection of what it means to experience empathy in the moral domain. The description offers a new perspective from which to view empathic declines that have been previously reported, while also highlighting a moral‐behavioural tension that has implications for competency‐based assessment and the way empathy is conceptualised in medical education.
Coordinated resource allocation to plant growth–defense tradeoffs
Authors: Monson Russell K. , Trowbridge Amy M. , Lindroth Richard L. , Lerdau Manuel T.
Published: October 2021

Plant resource allocation patterns often reveal tradeoffs that favor growth (G) over defense (D), or vice versa. Ecologists most often explain G–D tradeoffs through principles of economic optimality, in which negative trait correlations are attributed to the reconciliation of fitness costs. Recently, researchers in molecular biology have developed ‘big data’ resources including multi‐omic (e.g. transcriptomic, proteomic and metabolomic) studies that describe the cellular processes controlling gene expression in model species. In this synthesis, we bridge ecological theory with discoveries in multi‐omics biology to better understand how selection has shaped the mechanisms of G–D tradeoffs. Multi‐omic studies reveal strategically coordinated patterns in resource allocation that are enabled by phytohormone crosstalk and transcriptional signal cascades. Coordinated resource allocation justifies the framework of optimality theory, while providing mechanistic insight into the feedbacks and control hubs that calibrate G–D tradeoff commitments. We use the existing literature to describe the coordinated resource allocation hypothesis (CoRAH) that accounts for balanced cellular controls during the expression of G–D tradeoffs, while sustaining stored resource pools to buffer the impacts of future stresses. The integrative mechanisms of the CoRAH unify the supply‐ and demand‐side perspectives of previous G–D tradeoff theories.
Stress associated proteins coordinate the activation of comprehensive antiviral immunity in Phalaenopsis orchids
Authors: Chang Li , Tzean Yuh , Hsin Kuan‐Ting , Lin Chia‐Ying , Wang Chun‐Neng , Yeh Hsin‐Hung
Published: October 2021

Viruses cause severe damage on crops, and identification of key gene(s) that can comprehensively activate antiviral immunity will provide insights for designing effective antiviral strategies. Salicylic acid (SA)‐mediated antiviral immunity and RNA interference (RNAi) are two independently discovered antiviral pathways. Previously, we identified the orchid stress‐associated protein (SAP), Pha13, which serves as a hub in SA‐mediated antiviral immunity. As SAPs exist as a protein family, whether duplicated SAPs have redundant or distinctive functions in antiviral immunity remains elusive.

We performed functional assays on orchid Pha21, a homolog of Pha13, using transient and transgenic approaches on orchid, Arabidopsis and Nicotiana benthamiana to overexpress and/or silence Pha21.

The SA treatment induced the expression of both Pha13 and Pha21, whereas Pha21 was found to play a key role in the initiation of the RNAi pathway in Phalaenopsis orchids. We demonstrated that Pha21‐mediated antiviral immunity and enhancement of the RNAi pathway is conserved between dicotyledons and monocotyledons.

We provide new insight that orchid SAPs confer distinctive functions to coordinate both SA‐signaling and RNAi for comprehensive activation of antiviral immunity, and this information will help us develop antiviral strategies on crops.
Justification, excuse, and proof beyond reasonable doubt
Authors: Ho Hock Lai
Published: October 2021

The law requires criminal guilt to be proved beyond a reasonable doubt. There are two different approaches to construing this legal rule. On an epistemic approach, the rule is construed in terms of justified belief or knowledge; on a probabilistic approach, the rule is construed in terms of satisfying a probabilistic threshold. An epistemic construction of the rule has this advantage over a probabilistic construction: the former can while the latter cannot excuse the state from blame for a false conviction. This claim rests on an understanding of legal rules, legal justification for a finding of guilt and the central purpose of a criminal trial.
Evaluation of Israeli healthcare workers knowledge and attitudes toward the COVID‐19 vaccine
Authors: Zaitoon Hussein , Sharkansky Livnat , Ganaim Loai , Chistyakov Irina , Srugo Isaac , Bamberger Ellen
Published: October 2021

Objectives

Healthcare workers (HCWs) are considered an important target group for the COVID‐19 vaccines. The current study assesses the knowledge and attitudes of Israeli HCWs regarding COVID‐19 immunization, and how various occupational and demographic factors may underlie COVID‐related knowledge and attitudes differences.

Methods

Following a pre‐test to validate measures, a cross‐sectional online anonymous survey was distributed to HCWs using a snowball sampling method.

Results

The survey was completed by 714 participants (mean age 39.9; range 18–74; 447 female), 52% doctors, 32% nurses, and the remainder by paramedical staff. Of the respondents, 553 (77.4%) answered the question are you in favor of getting the COVID‐19 vaccine, 105 (14.7%) were not sure, and 56 (7.8%) were not in favor. Doctors had higher odds of agreement as compared to both nurses (p < .025) and paramedical staff (p < .001). Multivariate logistic regression analysis revealed that increased age (OR: 1.075; 95% CI: 1.04–1.11, p < .001), profession (physician vs. nurse; OR: 2.73; 95% CI: 1.32–5.65; p < .007), and getting the current influenza vaccine (OR: 4.96; 95% CI: 2.47–9.95) were significant predictors of agreement.

Conclusions

A high level of HCWs knowledge and in favor attitudes were observed. Yet negative attitudes were also noted, particularly among nurses, paramedical staff, and young employees.
A Meta‐Analysis of the Government Performance—Trust Link: Taking Cultural and Methodological Factors into Account
Authors: Zhang Jiasheng , Li Hui , Yang Kaifeng
Published: October 2021

The performance‐trust link constitutes an important issue, but the public administration and political science literature has been equivocal regarding how it is influenced by cultural and methodological factors. Meta‐analyzing 72 empirical studies, this article finds that the link is stronger in low power distance countries, when outputs are used to measure government performance, or when the focus is on local government. In addition, the performance‐trust link holds true regardless of whether performance data are subjective or objective, or whether the studies focus on performance of government as a whole or specific agencies. The results imply that in order to nurture and sustain trust in government, we should pay more attention to societal cultures and the way government performance information is provided. Trust in government studies should become both more scientific and more culturally sensitive.
Copula measures and Sklar's theorem in arbitrary dimensions
Authors: Benth Fred Espen , Di Nunno Giulia , Schroers Dennis
Published: October 2021

Although copulas are used and defined for various infinite‐dimensional objects (e.g., Gaussian processes and Markov processes), there is no prevalent notion of a copula that unifies these concepts. We propose a unified functional analytic framework, show how Sklar's theorem can be applied in certain examples of Banach spaces and provide a semiparametric estimation procedure for second‐order stochastic processes with underlying Gaussian copula.
Characterization of the novel HLA‐B*13:02:01:18 allele in a North Indian individual
Authors: Phuntsok Tenzin , Tambe Manisha , D'Silva Selma Z. , Rajak Jyoti , Singh Meenakshi
Published: October 2021

The novel HLA‐B*13:02:01:18 allele differs from HLA‐B*13:02:01:01 by A‐>G nucleotide change at gDNA 2477.
Molecular identification of Acanthamoeba genotypes isolated from oral cavity of heart transplant patients in Iran
Authors: Arab‐Mazar Zahra , Niyyati Maryam , Javanmard Ehsan , Kamali Monireh , Lasjerdi Zohreh , Rahmati Roodsari Sara
Published: October 2021

Objective

Heart transplant is one of the accepted treatments for some patients with advanced heart failure. Of note, transplant surgeries may cause different infections and complications for patients during the post‐transplant period. A wide variety of opportunistic organisms caused these infections including bacteria, fungi, viruses, and protozoa particularly Free‐living amoebae (FLA). This study aims to study the presence of pathogenic FLA from the oral cavity of post‐heart transplant recipients.

Methods

Throat swabs were collected from 80 patients who underwent post‐heart transplant surgery. All swabs were immediately cultured in non‐nutrient agar (2%). PCR and sequencing of 18S rRNA gene (DF3 region) of Acanthamoeba isolates were performed using genus‐specific primers. Genetic associations among sequenced genotypes inferred by the 18S rRNA gene obtained by MEGA X and a phylogenetic tree were constructed using the maximum likelihood algorithm and Kimura 2‐parameter model.

Results

Out of 80 samples collected from post‐heart transplant patients, six (7.5%) samples showed positive outgrowth of Acanthamoeba based on the page key and sequencing of the DF3 region. Sequence similarity of ASA1 by basic local alignment search tool(n) showed that five isolates (ANHT1, ANHT2, ANHT3, ANHT4, and ANHT5) belonged to Acanthamoeba T5 genotype corresponding to A. lenticulata and one strain (ANHT6) belonged to the T4 genotype.

Conclusion

To the best of our knowledge for the first time, a comprehensive study of Acanthamoeba genotypes isolated from throat samples of heart transplant recipients is described. Heart transplantation patients can be colonized by FLA and are therefore at risk of developing an invasive infection. Physicians' awareness of central nervous system infections related to FLAs and preventive and control measures of patients with compromised immune status due to heart transplant surgery are of utmost importance.
Estimating the impact on the inventory of implementing pathogen‐reduced platelets in Canada
Authors: Blake John T. , McTaggart Ken , Couture Chantal
Published: October 2021

Background

Pathogen reduction (PR) technology will be implemented in pooled platelets in Canada. It is anticipated that PR platelets will be licensed in Canada for a maximum shelf life of 5 days, while non‐treated apheresis platelet products will continue to be licensed for 7 days.

Study Design and Methods

This study evaluates the impact on inventory, wastage, and shortages of implementing PR platelets. A custom‐built simulation model was used to represent a regional distribution network. Experiments with the model were used to estimate product wastage and shortages when a 5‐day PR pooled platelet product is introduced alongside a 7‐day apheresis platelet product.

Results

Pooled platelet waste and shortages both increase as pooled shelf life decreases. Apheresis platelets, however, show a different response: While shortages of apheresis platelets increase as the shelf life of pooled units decreases, apheresis waste declines as pooled shelf life decreases.

Conclusion

Additional platelet collections will be necessary to accommodate the shorter PR platelet shelf life and to cover increased patient transfusion needs due to a lower platelet yield in PR units. Increases of 9% for pooled units and 6% for apheresis units beyond expected demand, were found to be sufficient to ensure a non‐inferior level of customer service while minimizing waste.
AMARTYA SEN'S CAPABILITIES APPROACH: RESISTANCE AND TRANSFORMATIVE POWER IN THE AGE OF TRANSHUMANISM
Authors: Yoon I Sil
Published: October 2021

Although the development of transhuman technologies has the potential to radically improve the quality of human life, transhumanism risks widening existing socio‐economic disparity. A side effect of innovative advance in AI (artificial intelligence) and IA (intelligence amplification) would be a society with a large underclass dominated by a techno‐elite. For my analysis, I will draw on Amartya Sen's Capabilities Approach, which focuses on opportunities that make possible an individuals’ capabilities of choosing to pursue their life values and well‐being. This article explores how Sen's approach can serve as a foundational framework to critique capitalism‐driven technological development and consequent social inequality. It further examines how it can serve as guidance for a democratic and just transhumanist society by necessitating the establishment of social conditions where all persons can flourish.
Chromosome numbers of eight Carex taxa in Korea (Cyperaceae)
Authors: CHUNG Kyong-Sook , CHUNG Gyu Young
Published: October 2021

In the flora of Korea, Carex L. is one of the most species-rich genera. Among nearly 157 Carex taxa, less than 30 have had their chromosome numbers reported. We report the meiotic chromosome numbers of eight Carex taxa from Korean populations, which include the first count for C. accrescens Ohwi (n = 37II) and the first chromosome investigations of Korean populations for three taxa: C. bostrychostigma Maxim. (n = 22II), C. lanceolata Boott (n = 36II), and C. paxii Kük. (n = 38II). In most species, chromosome counts observed in the study are included within the variation ranges of previous chromosome numbers. However, C. bostrychostigma Maxim. (n = 22II) and C. planiculmis Kom. (n = 29II) are assigned new chromosome numbers. Carex is known to have holocentric chromosomes, lacking visible primary constrictions and exhibiting great variance in its chromosome number. Further investigations of the diversity of Carex chromosomes will provide basic information with which to understand the high species diversity of the genus.
New records of flowering plants collected from the Phou Khao Khouay National Biodiversity Conservation Area for the flora of Laos
Authors: LIM Chang-Kun , LEE Kyoung-Eun , CHO Hyun-Sung , SAYSAVANH Veosavanh , WON Hyosig
Published: October 2021

We report 14 species of flowering plants as new additions to the flora of Laos. These are Illex viridis (Aquifoliaceae), Capparis erycibe (Capparaceae), Euphorbia bokorensis (Euphorbiaceae), Exacum darae (Gentianaceae), Aeschynanthus cambodiensis (Gesneriaceae), Tetraphyllum roseum (Gesneriaceae), Utricularia gibba (Lentibulariaceae), Macrosolen brandisianus (Loranthaceae), Decaschistia siamensis (Malvaceae), Nyssa yunnanensis (Nyssaceae), Adenia penangiana var. penangiana (Passifloraceae), Pentaphylax euryoides (Pentaphylacaceae), Wikstroemia bokorensis (Thymelaeaceae), and Debregeasia wallichiana (Urticaceae). We discovered the species during a botanical survey of the Phou Khao Khouay National Biodiversity Conservation Area (PKKNBCA) of Lao PDR in 2015-2019. In addition, nine rarely collected flowering plant species in Laos are newly reported for the PKKNBCA.
An investigation on using measurement uncertainty as decision rule for statement of conformity
Authors: Mohamed Gouda M. , Hegazy Riham S.
Published: October 2021

This research article refers to the application of the evaluated measurement uncertainty for deciding the statement of conformity. It is a proposal to rethink about the classification of measuring devices, taking into account the calculations of uncertainty as a decision rule. It is also a base for complete compatibility and harmonization between ISO 17025:2017 and the other standards. To verify this proposal a case study on compression testing machine classification is used. This proposal aims to review classification criteria for these machines. Since the uncertainty value is equivalent to all parameters that may affect the performance of these machines, it is logical and accurate to use it as the basis for the classification. This approach may be employed for the upcoming version of ISO 7500 standard to use the uncertainty value as a base for machine classification.
A Study on Adapted Similitude Modeling Method of Turboexpander With Different Gas Working Fluids
Authors: Li Yiran , Wang Xing , Zhang Xuehui , Zhu Yangli , Li Wen , Chen Haisheng
Published: October 2021

The study on similitude modeling method of turboexpander with different working fluids is not only the key technical means and necessary method for the research and development of turboexpander with special working fluids but also an effective way to further expand the application scope of a turboexpander. In this paper, an adapted similitude modeling method (ASMM), which is based on dimensional analysis, actual characteristics of real gas, and seven similitude criteria, is proposed. Based on modeling criterion π4, the new similitude modeling relationship of turboexpander with different gas working fluids is obtained based on rotational speed, inlet total temperature, specific heat ratio, and gas constant. Aiming at the ASMM, the similitude modeling performance of turboexpander with air, methane, CO2, and helium is verified by using the computational fluid dynamics method. The results show that the modeling effects on aerodynamic performance are well predicted in a wide range including the design point (expansion ratio 2.9∼5.0), and the errors of the total-to-total isentropic efficiency, relative equivalent mass flow rate, relative equivalent shaft power are less than 0.74%, 1.94%, and 1.69%, respectively. Methane and CO2 have the best modeling performance, their errors of efficiency, relative equivalent mass flow rate, and relative equivalent shaft power are all less than 0.5%; Furthermore, the ASMM also has pinpoint accuracy with the prediction of the internal flow field, which provides a good idea for further research on special working fluid turboexpander and an approach to expand the application scope of turboexpanders.
Flow and Heat Transfer Mechanisms in a Rotating Compressor Cavity Under Centrifugal Buoyancy-Driven Convection
Authors: Gao Feng , Chew John W.
Published: October 2021

This paper presents a systematic study of flow and heat transfer mechanisms in a compressor disk cavity with an axial throughflow under centrifugal buoyancy-driven convection, comparing with previously published experimental data. Wall-modeled large-eddy simulations (WMLES) are conducted for six operating conditions, covering a range of rotational Reynolds number (3.2×105−2.2×106), buoyancy parameter (0.11–0.26), and Rossby number (0.4–0.8). Numerical accuracy and computational efficiency of the simulations are considered. Wall heat transfer predictions are compared with measured data with a good level of agreement. A constant rothalpy core occurs at high Eckert number, appearing to reduce the driving buoyancy force. The flow in the cavity is turbulent with unsteady laminar Ekman layers observed on both disks except in the bore flow affected region on the downstream disk cob. The shroud heat transfer Nusselt number–Rayleigh number scaling agrees with that of natural convection under gravity for high Rayleigh numbers. Disk heat transfer is dominated by conduction across unsteady Ekman layers, except on the downstream disk cob. The disk bore heat transfer is close to a pipe flow forced convection correlation. The unsteady flow structure is investigated showing strong unsteadiness in the cavity that extends into the axial throughflow.
Manipulator Kinematics and Dynamics on Differentiable Manifolds: Part I Kinematics
Authors: Haug Edward J.
Published: October 2021

Using basic tools of Euclidian space differential geometry, maximal singularity free components of the regular manipulator configuration space are defined, with conditions that establish the space as a differentiable manifold. This structure shows that the conventional categorization of manipulators as either serial or parallel is incomplete and that three distinct categories of manipulator must be accounted for; (1) serial manipulators in which inputs globally determine outputs, (2) explicit parallel manipulators in which outputs globally determine inputs, and (3) compound manipulators in which there is no global input or output mapping. Results of differential geometry are used to show that configuration space differentiable manifolds in each category are partitioned into maximal, disjoint, path-connected components in which the manipulator is singularity free and may be effectively controlled. This extends local analytical properties of manipulators that are used for analysis and control to global validity on maximal components of regular manipulator configuration space, providing explicit criteria for avoidance of singular behavior. Model manipulators in each of the three categories are analyzed to illustrate application of the differentiable manifold structure, using only multivariable calculus and linear algebra. Computational methods for forward and inverse kinematics and construction of ordinary differential equations of manipulator dynamics on differentiable manifolds are presented in Part II of this paper, in support of manipulator control.
On the Determination of Thermal Conductivity From Frequency Domain Thermoreflectance Experiments
Authors: Saurav Siddharth , Mazumder Sandip
Published: October 2021

The Fourier and the hyperbolic heat conduction equations were solved numerically to simulate a frequency-domain thermoreflectance (FDTR) experiment. Numerical solutions enable isolation of pump and probe laser spot size effects and use of realistic boundary conditions. The equations were solved in time domain and the phase lag between the temperature of the transducer (averaged over the probe laser spot) and the modulated pump laser signal was computed for a modulation frequency range of 200 kHz–200 MHz. Numerical calculations showed that extracted values of the thermal conductivity are sensitive to both the pump and probe laser spot sizes, while analytical solutions (based on Hankel transform) cannot isolate the two effects. However, for the same effective (combined) spot size, the two solutions are found to be in excellent agreement. If the substrate (computational domain) is sufficiently large, the far-field boundary conditions were found to have no effect on the computed phase lag. The interface conductance between the transducer and the substrate was found to have some effect on the extracted thermal conductivity. The hyperbolic heat conduction equation yielded almost the same results as the Fourier heat conduction equation for the particular case studied. The numerically extracted thermal conductivity value (best fit) for the silicon substrate considered in this study was found to be about 82–108 W/m/K, depending on the pump and probe laser spot sizes used.
Manufacturing of a Gelatin Phantom With Lymphedema for Ultrasonic Imaging Measurement
Authors: Yoon Ki-Cheol , Kim Kwang Gi
Published: October 2021

For diagnosis of secondary lymphedema, amplitude mode (A-mode) examination using a single ultrasound probe has been suggested as one of the possible diagnostic modalities due to its relatively low cost, ease of usage, and mobility. However, A-mode ultrasound waves with respect to time have lots of noise and are complicated to analyze and achieve well-correlated information related to change in volume of each layer of skin and subcutaneous tissues. Thus, the development of an adequate ultrasound calibration phantom is needed. For this, a fundamental study on proper phantom materials which show acoustic characteristics of skin and subcutaneous tissues is needed. In this research, the fabrication method for ultrasonic phantom using gelatin material is presented in a wide range of acoustic impedance and their acoustic characteristics and usability were discussed.
Compressor Stability at Pulsating Condition Via Gas Dynamics Responses Analysis
Authors: Shu Mengying , Yang Bijie , Yang Mingyang , Martinez-Botas Ricardo F. , Zhuge Weilin
Published: October 2021

The compressor is operated at unsteady exit conditions in many scenarios such as the instability of combustion in gas turbine and denotation engine. The aerodynamic stability of the compressor is inevitably influenced by the unsteady operating environment. In this paper, a one-dimensional (1D) model that combines pulsation and unsteady responses of the compressor is developed to investigate the stability of the compressor system. The results show that the onset of surge and the transient responses of the compressor during surge are well predicted by the method. The amplitude of the component at surge frequency obtained by fast Fourier transformation (FFT) method is applied as a criterion to quantitively evaluate the onset and the strength of the surge. Compressor stability is enhanced at pulsating conditions due to the interaction between forced oscillation of pulsation and self-sustained oscillation of surge. An analytical model is established to understand the mechanism of the enhancement of compressor stability under pulsation. The change of total energy of the compressing system is proposed to evaluate the influence of pulsating conditions. Specifically, the energy change is reduced for pulsation conditions due to two aspects: the lower slope of compressor characteristic curve due to the lag-effect of compressor responses and the higher energy dissipation due to the nonlinear throttling effect.
An Efficient Design Procedure for MEMS Electrothermal Microgripper
Authors: Roy Ananya , Sarkar Rajasree , Banerjee Arunava , un Nabi Mashuq
Published: October 2021

With the development of miniaturization technology, micro-electromechanical system (MEMS) electrothermal microgrippers have been widely used owing to their compact size, ease of manufacturing, and low production cost. Since most of these systems are governed by partial differential equations (PDEs), modeling of microgrippers poses a significant challenge for designers. To reduce the overall computational complexity, it is a common practice to model the microgripper system using the finite element method (FEM). During the design process, the geometric and analytical properties of the microgripper influence the system dynamics to a great extent, and this work focuses on studying the effects of such parameter changes. In low-voltage applications, the performance of the microgripper is influenced by the geometrical variations, and the air gap. Hence, for the modeling of the microgripper, actuator arm lengths, and the gap between the arms are chosen as the two main geometric design parameters, while the input current density is considered as the analytical design parameter. In this work, the optimized design parameter values for maximum possible displacement are obtained with the use of sine cosine algorithm (SCA). Furthermore, an averaging operation is proposed for efficiently designing the MEMS electrothermal microgripper, and the efficacy of the proposed design methodology is demonstrated through simulation studies.
Autoignition of Reacting Hydrocarbon Mixture With Negative Temperature Coefficient Due to the Cold-Spot and Cold Chamber Wall
Authors: Samimi-Abianeh O.
Published: October 2021

Autoignition of an n-heptane/air mixture was simulated in nonuniform temperature environments of a rapid compression machine (RCM) and shock-tube (ST) with and without the presence of a cold-spot. The simulations were performed to investigate how the presence of a cold-spot and the cold boundary layer of the chamber wall may affect the ignition delay of the hydrocarbon mixture with negative temperature coefficient (NTC) behavior. The simulations were performed using three models: (1) three-dimensional (3D) computational fluid dynamics (CFD) model, (2) zero-dimensional (0D) homogenous batch reactor model by including the heat transfer model, and (3) 0D adiabatic homogenous batch reactor model. A detailed n-heptane mechanism was reduced in this work and used for 3D combustion modeling. A cold-spot critical radius of 7 mm was determined, which affects the ignition delay by more than 9%. In addition, two combustion modes were observed in the combustion chamber with a nonuniform temperature environment. With the first combustion mode, combustion starts at the high gas temperature region of the combustion chamber and quickly propagates toward the periphery of the chamber. In this combustion mode, the location of the maximum concentration of hydroxyl radical and the maximum temperature are the same. With the second combustion mode, the combustion starts at the periphery of the chamber, where the temperature is lower than the center of the chamber due to heat transfer to the cold chamber wall. The location of maximum concentration of the hydroxyl radical and maximum temperature is different with this combustion mode. The two observed combustion modes are due to the NTC behavior of the n-heptane mixture. The 0D homogenous batch reactor model (with and without heat transfer models) failed to mimic the ignition delay accurately when the second combustion mode was present. In addition, a propagating combustion has been observed in the simulation which is in agreement with some of the optical autoignition diagnostics of these hydrocarbons. This propagating combustion leads to a gradual pressure rise during autoignition, rather than a sharp pressure rise. The results of this work show that 0D homogenous batch reactor models are unable to simulate autoignition of mixtures with NTC behavior.
Component-Based Modeling and Simulation of Nonlinear Drill-String Dynamics
Authors: Tengesdal Njål Kjærnes , Holden Christian , Pedersen Eilif
Published: October 2021

In this article, we present a dynamic model for a generic drill-string. The model is developed with the intention for component-based simulation with coupling to external subsystems. The performance of the drill-string is vital in terms of efficient wellbore excavation for increased hydrocarbon extraction. Drill-string vibrations limit the performance of rotary drilling; the phenomenon is well known and still a subject of interest in academia and in industry. In this study, we have developed a nonlinear flexible drill-string model based on Lagrangian dynamics to simulate the performance during vibrations. The model incorporates dynamics governed by lateral bending, longitudinal motion, and torsional deformation. The elastic property of the string is modeled by the assumed mode method, representing the elastic deformation, with a finite set of modal coordinates. By developing a bond graph model from the equations of motion, we can ensure correct causality of the model toward interacting subsystems. The model is analyzed through extensive simulations in case studies, comparing the qualitative behavior of the model with state-of-the art models. The flexible drill-string model presented in this article can aid in developing system simulation case studies and parameter identification for offshore drilling operations.
Lubrication Effect of the Nozzle Layout for Arc Tooth Cylindrical Gears
Authors: Mo Shuai , Zhou Changpeng , Dang Heyu
Published: October 2021

In order to study the influence of fuel injection nozzle arrangement on the lubrication effect of arc tooth cylindrical gear, a model of fuel injection lubrication was established, and computational fluid dynamics (CFD) software was used for simulation calculation. The focus on the influence of gear parameters, oil jet conditions, and nozzle layout on gear lubrication performance is studied. The results show that reducing the oil jet distance not only improves the lubrication performance of the gear but also reduces the offset of the oil jet streamline. The reasonable nozzle layout is the premise of ensuring better lubrication conditions, and the best nozzle layout scheme is obtained through data comparison analysis. The lubrication effect decreases when the nozzle angle is offset. The lubrication effect does not change when the nozzle is horizontally offset by a distance of 0.5 module in the direction of the pinion, and the lubrication performance is degraded when the distance exceeds 0.5 module. Finally, the influence of nozzle diameter on lubrication is analyzed, the lubrication effect is directly proportional to the nozzle diameter.
Sliding Behavior of Silica Ball–Shale Rock Contact Under Polyacrylamide Aqueous Solutions
Authors: Zhang Huijie , Liu Shuhai
Published: October 2021

The tribological properties of proppant particle sliding on shale rock determine the shale gas production. This work focuses on investigating the impacts of sliding speed on the coefficient of friction (COF) and wear of the silica ball–shale rock contact, which was lubricated by water or different types of polyacrylamide (PAM) aqueous or brine solution. The experimental results show that both boundary and mixed lubrication occur under specific speed and normal load. COF and wear depth of shale rock under water are higher than those under PAM solution due to superior lubrication of PAM. COF of shale rock under PAM brine solution increases and the wear of the rock is more serious, attributed to the corrosion of shale rock and adverse effect on lubrication of PAM by brine.
Quenching Vibration on a Harmonically Excited Symmetric Laminated Composite Plate
Authors: Chen Jiawang , Cha Philip D. , Shen Yichang , Zhou Xiang
Published: October 2021

In this paper, a simple and efficient method is developed to quench the steady-state vibration of a harmonically excited, damped and symmetric laminated composite rectangular plate. This is achieved by enforcing points of zero displacement, or nodes, at some specified locations on the laminated composite plate using properly tuned damped oscillators. Using the assumed-modes method, the governing equations of the laminated composite plate carrying the damped oscillators are first formulated. A set of constraint equations is established by enforcing nodes at user-specified locations on the plate. Two attachment scenarios are considered: when the attachment and node locations coincide and when they are distinct. Numerical experiments show that for both cases, the damped oscillator parameters can be readily determined and the desired node locations can be successfully imposed. More importantly, enforcing nodes can suppress vibration in the vicinity of the node locations, thereby keeping that region of the laminated composite plate nearly stationary.
Mirror Cross-Exercise on a Kinetic Chain Approach Improves Throwing Performance in Professional Volleyball Athletes With Scapular Dyskinesis
Authors: Paraskevopoulos Eleftherios , Simeonidis Theocharis , Tsolakis Charilaos , Koulouvaris Panagiotis , Papandreou Maria
Published: October 2021

Context: Volleyball players have shown to be at an increased risk of developing scapular dyskinesis. The kinetic chain exercise approach has gained a lot of attention because of its claims to provide an improved motor control and scapular kinematics. A form of cross exercise, known as mirror therapy, may enhance the effects of a kinetic chain exercise approach in throwing performance. Objective: To examine the effects of mirror cross exercise (MCE), based on a kinetic chain exercise approach in the throwing performance of volleyball athletes with scapular dyskinesis. Design: Randomized controlled trial. Setting: Biomechanics laboratory. Methods: 39 volleyball players with scapular dyskinesis were randomly allocated into 3 groups. The first group completed a 6-week kinetic chain approach (KCA group), the second group completed a kinetic chain exercise approach program in addition to MCE group, and the control group followed only their regular training program. Before and after delivering both interventions, throwing accuracy, speed, and force were determined while measuring the ground reaction forces of the drive leg during throwing. Two-way mixed analysis of variance investigated the effects of intervention and time and their interaction. Results: The results showed intervention × time statistically significant interactions for throwing accuracy, speed, and force for the MCE and the KCA groups. Over the 6-week training period, the MCE and the KCA groups showed significant improvements in throwing accuracy (P < .01) and speed (P < .01), while the ground reaction forces did not change (P > .05). Throwing force increased significantly in the MCE group (P = .01). Between-group comparison showed statistically significant improvements in the throwing accuracy for the MCE and KCA groups against the control group (P < .01) at posttesting. The MCE demonstrated superior results over the KCA in the aforementioned measures. Conclusions: This study suggests that the addition of MCE in a KCA program enhances energy transfer throughout the distal and proximal segments, thus improving kinetic chain recruitment and potentially preventing shoulder pathology.
Gluteal Activity During Gait in Patients With Chronic Ankle Instability Following Rehabilitation: A Randomized Controlled Trial
Authors: DeJong Lempke Alexandra F. , Koldenhoven Rachel M. , Jaffri Abbis H. , Hertel Jay
Published: October 2021

Context:Ankle positioning gait biofeedback (GBF) has improved ankle inversion for patients with chronic ankle instability. However, the effects on proximal deficits remain unknown. The purpose of this study was to determine the effects of impairment-based rehabilitation with GBF and without biofeedback on gluteal activity during walking in patients with chronic ankle instability.Design:Randomized controlled trial.Methods:Eighteen patients with chronic ankle instability (14 women and 4 men; age 22 [4] y; height 171 [10] cm; mass 71.6 [13.8] kg) were recruited from a university setting, following International Ankle Consortium guidelines. Patients were randomly allocated to GBF or without biofeedback groups (N = 9 per group). Both groups performed 4 weeks of exercises and treadmill walking. The GBF group alone received feedback on frontal ankle positioning at initial contact during walking. Ultrasound videos of the gluteus maximus and medius were recorded during walking at baseline and follow-up by a blinded clinician. Gluteal activity ratios were obtained at each 10% of the gait cycle. Statistical parametric mapping repeated-measures analysis of variance were used to compare groups and time points.Results:Both groups demonstrated significantly increased gluteus medius activity across the gait cycle compared with baseline (P < .01, mean differences: 0.13–0.21, Hedgeg: 0.97–1.89); however, there were no significant between-group differences. There were no statistically significant changes noted for the gluteus maximus. No adverse events were observed.Conclusions:Impairment-based rehabilitation led to increased gluteus medius activity, but GBF did not provide any additional improvement to this parameter. Clinicians may consider implementing impairment-based strengthening interventions to improve gluteus medius function during gait for patients with CAI.
Type I interferon suppresses virus-specific B cell responses by modulating CD8
+
T cell differentiation
Authors: Moseman E. Ashley , Wu Tuoqi , de la Torre Juan Carlos , Schwartzberg Pamela L. , McGavern Dorian B.
Published: October 2021

Type I interferon–driven CD8
+
T cells suppress neutralizing antibody production during chronic LCMV infection.

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circumvents neutrophils and neutrophil extracellular traps during amniotic cavity invasion and preterm labor
Authors: Boldenow Erica , Gendrin Claire , Ngo Lisa , Bierle Craig , Vornhagen Jay , Coleman Michelle , Merillat Sean , Armistead Blair , Whidbey Christopher , Alishetti Varchita , Santana-Ufret Veronica , Ogle Jason , Gough Michael , Srinouanprachanh Sengkeo , MacDonald James W. , Bammler Theo K. , Bansal Aasthaa , Denny Liggitt H. , Rajagopal Lakshmi , Adams Waldorf Kristina M.
Published: October 2021

Group B streptococci overcome neutrophils in placental membranes, inducing fetal injury and preterm labor.
Combined use of a Total Control Introducer and a hyperangulated video laryngoscope to place a left-sided double lumen endotracheal tube in a patient with a history of difficult laryngoscopy
Authors: Pollard Jacob E , Smith D Warner , Morgan David E , Skaggs John D
Published: October 2021

We describe the use of a Total Control Introducer (TCI) in combination with video laryngoscopy (VL) to place a left-sided double-lumen endotracheal tube (DLT) in a patient with a history of difficult laryngoscopy undergoing video-assisted thoracoscopic surgery (VATS). VL was used to obtain visualisation of the glottis and a TCI articulating introducer was used to dynamically navigate the airway and access the trachea. A 39 French DLT was subsequently passed over the TCI shaft and into the trachea under indirect visualisation. The TCI shaft was removed and the DLT was gently guided into the left main bronchus. Successful endobronchial intubation was confirmed with capnography, auscultation and fibreoptic bronchoscopy. We propose that the combined use of VL and a TCI can facilitate placement of a DLT in a patient with a known difficult airway who may otherwise be limited to a bronchial blocker placement for lung isolation during VATS.
Pulse oximetry and supplemental oxygen use in nationwide Veterans Health Administration hospitals, 2013–2017: a Veterans Affairs Patient Database validation study
Authors: Wang Xiao Qing , Iwashyna Theodore , Prescott Hallie , Valbuena Valeria , Seelye Sarah
Published: October 2021

Objective

Extraction and standardisation of pulse oximetry and supplemental oxygen data from electronic health records has the potential to improve risk-adjustment, quality assessment and prognostication. We develop an approach to standardisation and report on its use for benchmarking purposes.

Materials and methods

Using electronic health record data from the nationwide Veteran’s Affairs healthcare system (2013–2017), we extracted, standardised and validated pulse oximetry and supplemental oxygen data for 2 765 446 hospitalisations in the Veteran’s Affairs Patient Database (VAPD) cohort study. We assessed face, concurrent and predictive validities using the following approaches, respectively: (1) evaluating the stability of patients’ pulse oximetry values during a 24-hour period, (2) testing for greater amounts of supplemental oxygen use in patients likely to need oxygen therapy and (3) examining the association between supplemental oxygen and subsequent mortality.

Results

We found that 2 700 922 (98%) hospitalisations had at least one pulse oximetry reading, and 864 605 (31%) hospitalisations received oxygen therapy. Patients monitored by pulse oximetry had a reading on average every 6 hours (median 4; IQR 3–7). Patients on supplemental oxygen were older, white and male compared with patients not receiving oxygen therapy (p<0.001) and were more likely to have diagnoses of heart failure and chronic pulmonary diseases (p<0.001). The amount of supplemental oxygen for patients with at least three consecutive values recorded during a 24-hour period fluctuated by median 2 L/min (IQR: 2–3), and 81% of such triplets showed the same level of oxygen receipt.

Conclusion

Our approach to standardising pulse oximetry and supplemental oxygen data shows face, concurrent and predictive validities as the following: supplemental oxygen clusters in the range consistent with hospital wall-dispensed oxygen supplies (face validity); there are greater amounts of supplemental oxygen for certain clinical conditions (concurrent validity) and there is an association of supplemental oxygen with in-hospital and postdischarge mortality (predictive validity).