bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat transfer from the heated by an electric current vertical rod in the regime of non-stationary natural convection
Authors: Mitin K A , Mitina A V , Berdnikov V S
Published: April 2021

The heat transfer from a vertical silicon rod heated by passing an electric current, placed in a cylindrical container filled with gas, with isothermal cold side walls, in the regime of non-stationary conjugate natural convection heat exchange, is studied numerically by the finite element method in a three-dimensional formulation of the problem. On the surface of the rod, a control point is selected, at which a constant temperature is maintained by changing the voltage of the electric current. The equations of thermogravitational convection are solved in the Boussinesq approximation in the terms of temperature, vortex, and vector field potential. The spatial form of convective flows is investigated. Temperature fields in a gas and in a solid are investigated. The calculations were performed with the Prandtl number equal to 0.67 and the Rayleigh number range from 104 to 5•105.
Processing of products with pulsed laser radiation
Authors: Khayrullina L R , Smorodin F K
Published: April 2021

This article is devoted to experimental studies of pulsed cutting of B93 aluminum alloy of holes, grooves in combustion chambers and the inlet fairing of a gas turbine engine, which were carried out with the change of the following parameters: laser power, cutting speed, frequency and duration of pulses, deepening of the focal spot into the material. The dependences of the cutting speed, laser radiation power on the cutting width and surface roughness were obtained, the results show an increase in the quality of cutting with the use of compressed air and an increase in the quality of processing.
Application of Langmuir probe and optical emission spectroscopy for bromofluorocarbon plasma diagnostics
Authors: Kuzmenko V , Miakonkikh A , Rudenko K
Published: April 2021

The Langmuir probe and optical emission spectroscopy were applied for diagnostics of C2F4Br2 low-pressure inductively coupled plasma. Electron temperature, plasma potential and concentrations of electrons, and positive ions, as well as fluorine and bromine radicals, were determined. An explanation of the results of experiments on the etching of low-k dielectrics in the studied plasma was proposed.
Diagram of the plasma torch discharge chamber
Authors: Akhatov M.F. , Kayumov R. R. , Mardanov R. R. , Saifutdinova I. I , Khazeev K. I.
Published: April 2021

The results of experimental studies of the effect of an electric discharge on carbon fiber in the discharge voltage range U = 0.2 - 1300 V and at a current I = 0.03 - 1.8 A, at atmospheric pressure are presented. Some features of the combustion of an electric discharge with liquid electrodes are revealed. Some features of the effect of an electric discharge on carbon fiber have been established.
Dynamic Measurement Device of Aeroengine Pressure Probe
Authors: Li B , Zhang H Y , Yang J , Zhang Z J
Published: April 2021

In order to improve the dynamic performance evaluating abilities of the pressure probe of the aeroengine, by loading sine pressure with variable static pressure and temperature and measuring the dynamic pressure process, the pressure probe is calibrated. The dynamic pressure device based on the electroacoustic transducer can produce (20∼1000) Hz sinusoidal pressure within 1 MPa static pressure environment, and the sinusoidal pressure amplitude can reach 10 kPa. The temperature system is established by the convection heating mode to provide (20∼400) °C temperature environment for the pressure probe. The dynamic measurement device of pressure probe with controllable static pressure and temperature is established. The performance of the device is tested, and the test results are stable and reliable. The device is used for dynamic measurement of traditional pressure sensor and pressure probe. The device can simulate the work environment of the tested object and could be widely used in dynamic characteristics tests and evaluation of the pressure probe and other pressure system with transmission pipe.
Development of an Intelligent Office Chair by Combining Vibrotactile and Visual Feedbacks
Authors: Liu J
Published: April 2021

The intelligent office chair has become increasingly popular with the development of the Internet of Things (IoT), wireless communication technology, sensing technology, and intelligent control technology. A smart office chair can monitor sitting behavior and trigger an alert message to the user, aiming to correct his posture and improve the sitting behavior. Visual and vibrotactile feedback are two techniques widely adopted to provide feedback. Studies indicated that vibrotactile feedback is a more effective way to attract the user’s attention. However, vibrotactile feedback can’t instruct users to adjust their sitting behavior. Meanwhile, the visual feedback can be easily ignored but provides explicit instructions on adjusting sitting behavior. This paper proposed to develop an intelligent office chair prototype integrating ergonomic office chair, sensors, microcontroller, vibration actuators, and mobile App. This chair aims to provide both vibrotactile and visual feedback to monitor the user ’s posture and improve their sitting behavior.
Double Rough Surface Contact Model and Finite Element Simulation based on Fractal Theory
Authors: SONG Jianfeng , Wang Wenwu , LANG Yuedong , DONG Yonggang , Luo Guoling
Published: April 2021

The contact between two rough surfaces is essentially the contact between micro-bulge of different shapes. In the process of interference fit, the distribution of contact area and contact stress at different positions of the two rough contact surfaces is uneven. In this paper, based on the test results of the morphology of machined surfaces with different surface roughness, a two-dimensional curve model of the contact surface is established according to the W-M fractal function and Matlab software. The contact area and contact load are analyzed with a two-dimensional finite element contact model of the double rough surface that established with Abaqus software. And the effect of surface roughness and surface displacement on the contact area and contact load is analyzed with the finite element contact model.
Acquisition and Analysis Technology of Pyroshock Response on Spacecraft
Authors: Feng Guosong , Yang Guang , Yang Jiang , Ma Gongbo , Wang Rui , Liu Chuang
Published: April 2021

Wide frequency range and high acceleration amplitude are two typical characteristics of transient vibration in the environment of pyroshock on spacecraft. The Piezoelectric accelerometer is widely accepted as the best available transducer for the absolute measurement of vibration. “Ringing” and “Zero Drift” are very easily to occur if the accelerometer is being used to measure transient vibrations outside its useful frequency range. This paper introduced the working principle of piezoelectric accelerometer, The scheme of reducing “Ringing” phenomenon was given, The mechanism of “Zero Drift” phenomenon was analysed. The methods to restrain the “Zero Drift” were discussed from the aspects of the selection of test equipment, the installation of piezoelectric accelerometer and the setting of data acquisition parameters. Finally, the wavelet analysis method was used to decompose and reconstruct the distortion data caused by “Zero Drift”, and the effective pyroshock response signal was extracted.
A Review of The Development of Civil Aircraft Family
Authors: Yongjie Zhang , Yongqi Zeng , Kang Cao , Wenjun Dong , Dayong Dong
Published: April 2021

The development of product family has become a major trend in industrial product research and development, which can meet the needs of market segments, shorten research and development time, reduce research and development costs, and quickly increase market share. The development of civil aircraft family is one of the important characteristics of modern civil aircraft design, which can bring significant economic benefits for aircraft life cycle. In order to meet the needs of the market and realize cost reduction and efficiency increase, the development of civil aircraft family has become the main direction of the development of modern civil aircraft, which has attracted widespread attention, and the major aircraft manufacturers have formed their own series of civil aircraft. Focusing on the development of civil aircraft family, this paper reviews the development of product family, the design of civil aircraft family and the development status of typical civil aircraft family in the field of civil aircraft. Then the challenges and future research directions of civil aircraft family are summarized and discussed.
Rapid Acoustic-vibration Modelling Methods of Solar Arrays in Satellites
Authors: Zhang Jie , liu Huiliang , Xie Weihua , Yin Jiacong , Zhou Jiang
Published: April 2021

Large components outside satellite body are extremely sensitive to the sound field. As the entire satellite acoustic-vibration (hereinafter referred to as acoustic) model is very complex, computationally intensive and time-consuming, the feasibility of only modelling these large components when they are just concerned deserves to be investigated. In this paper, an entire satellite model, a finite element (FE) model a statistical energy analysis (SEA) model of the solar array were firstly established, and then their results and time needed were compared in order to explore the fastest and most efficient modelling method of large components outside satellite body. The results demonstrate that modelling only solar array not the entire satellite is feasible when only it is concerned. The FE model of solar array should be used if the responses at each point are necessary, while the SEA model is recommended if not.
Analysis of Air Distribution and Comfort in Large Space Environment Simulator
Authors: Wenjing Ding , Jinghao Xu , Songlin Hu , Liming Zhang , Ang Li
Published: April 2021

The objective of this paper is to analyze the air distribution and comfort in large space environment simulator under different air supply for the same boundary and initial conditions. This is done by conducting the numerical simulations and contrasting the distribution of velocity and temperature field, PMV-PPD and air age. It can be analyzed that the influence of several air supply on air quality and thermal comfort inside the equipment, which can be as a reference for the improvement and optimization of airflow distribution with the device. This device owns three openable doors, which locate in the bottom, middle and top of the equipment. Open one of them, the ventilation will be achieved. Computational Fluid Dynamics (CFD) is used for it is easier and less time consuming to accomplish that purpose. In general, different air supply have important effect on the air distribution and comfort inside the device. Meanwhile, the comfort is acceptable in most area, however, the air age is on the high side.
Effect of spatial variability of soil properties on permanent seismic displacements of slopes with uniform load
Authors: Alamanis Nikolaos , Dakoulas Panos
Published: April 2021

The purpose of this study is to investigate the development of permanent displacements of earth slopes, with spatially varying properties and a uniform surface load, subjected to a strong seismic excitation. The uncertainties associated with the determination of the mechanical properties of the slopes and the intensity of the seismic excitation, make the use of stochastic methods very attractive. As opposed to deterministic methods, stochastic methods allow an acceptable risk level based on the specifications of each project. Recent research described the spatial variability of soil parameters using the Random Field Theory. Apart from the prescribed statistical characteristics and cross-correlation of the various soil properties, the generated random field variables exhibit autocorrelation, a trend in which the soil properties of a point appear to be correlated with the soil properties of neighbouring points. Among the various random field algorithms, a particularly effective one is the Local Average Subdivision (LAS) method by Fenton and Vanmarcke [1]. To this end, a large number of random fields of soil properties is generated for a natural slope, having prescribed mean value μ, standard deviation σ, cross-correlation coefficients pij
of properties i and j, and spatial autocorrelation lengths lx
and ly
for the vertical and horizontal directions, respectively. The numerical simulations are achieved using an automated procedure, based on collaboration of Mathematica, the incorporated LAS algorithm, and the finite difference program FLAC. The studied slope is loaded with a uniform load and subjected to a seismic shaking of various intensities using a series of acceleration records obtained from the five different earthquakes. The paper focuses mainly on the development of permanent seismic displacements of the slope at the end of ground shaking. It is demonstrated that the spatial variability of soil properties has a significant effect on the values of permanent displacements, resulting to a wide range of displacement variation.
Tensile Strength of Cement Treated Clay
Authors: Azneb A.S , Banerjee Subhadeep , Robinson R.G
Published: April 2021

Tensile properties of geomaterials often play an important role in many geotechnical engineering problems. Compacted soil layers in dams, clay liners in landfills, reinforced earth-retaining wall systems, cement stabilized crushed rocks in pavements, etc. are constantly checked for tensile cracking. This type of cracking happens when the developed tensile stress exceeds the tensile strength of the material. Usually, the tensile strength of natural soil is assumed to be negligible. However, it is proven that cement treated soils possess some amount of tensile strength. The determination of tensile strength of cement treated clay, using a newly developed tensile testing apparatus, is focussed in this study. The existence of an optimum cement content for tensile strength is also discussed.
Role of Geotechnical Engineering in BIM process modelling
Authors: Vaníček I , Jirásko D , Vaníček M
Published: April 2021

BIM “Building Information Model” creates a significant step forward in the whole process of construction. The role of geotechnical engineering will be shown as for classical building engineering so for civil engineering structures. In the first case all upper structures are in interaction with ground (subsoil), when foundation structures are basic element of this interaction. The 3D Ground model and 3D Foundation structure model create therefore one of the first individual parametric elements around basic (coordinating) BIM model. Some specificity will be shown as the impact of step by step creation (nD dimension) of the Ground model for the earliest building conception. Roughly the same is valid for civil engineering structures. Some specificity will be shown for earth structures of transport engineering, as a selection of borrow pit, definition of soil compaction for fill, fill compaction or any other methods of soil improvement and its control as they create important elements for the safe and optimal embankment design and performance. Final 3D Ground model together with 3D Geotechnical structure model (real performance) create the important base for the future decision making, when some changes will occur.
Swell-shrink and hydraulic behaviour of compacted red soil-bentonite mixture
Authors: Devapriya A S , Thyagaraj T
Published: April 2021

Clay liners are provided in waste landfills to prevent the leachate from percolating into underlying soil and ground water and polluting it. Hence, soils used as landfill liners must possess low hydraulic conductivity (< 10−7 cm/s). In the initial as-compacted state, liners satisfy this design criterion. However, in the field, liners are subjected to alternate wet-dry cycles and the initial microstructure of liners change, thereby affecting their hydraulic properties. The present study was conducted on a locally available red soil mixed with bentonite so that it satisfies the requirement of hydraulic conductivity in the as-compacted state. To achieve this objective, identical specimens compacted at optimum moisture content to its maximum dry density were inundated with distilled water under a surcharge load of 12.5 kPa. Upon attainment of maximum swelling, hydraulic conductivity tests were conducted at swollen state under a hydraulic gradient of 20. The soil specimens were then dried at a temperature of 45±2 °C. The weight, height and diameter of specimens were measured continuously during drying to study the shrinkage behaviour of the soil. The dried specimens were subjected to subsequent wet-dry cycles until the specimens reached an equilibrium state and the hydraulic conductivity was determined after each wetting cycle. SEM images were also captured to analyse the changes in the soil structure in the as-compacted state and at the end of different wetting cycles.
Seismic Response of Mechanically Stabilised Earth Retaining Wall
Authors: Joseph M , Banerjee S
Published: April 2021

Mechanically Stabilised Earth retaining wall has become a premier choice of retaining wall design in places where seismic and high vibration loads are frequent. The wall displacement has to be monitored regularly for the safe and economic function of the structure. In the present paper, a numerical study on an MSE wall model under real records of earthquake loading condition using an explicit finite difference program has carried out. A parametric study to scrutinize the influence of strong-motion parameters such as peak ground acceleration and predominant frequency on the permanent displacement of the wall is accomplished. The influence of PGA and frequency of seismic excitation was visible in the results. At higher frequencies, the ground surface is disturbed severely leading to excessive heaving on the surface. The amplification of strong motion along the backfill is observed for low PGA motions, whereas, de-amplification is observed for high PGA motion.
Preliminary study of a bridge abutment settlement considering spatial variability of soil properties
Authors: Pula W , Antczak M , Baginska I , Castrignano A , Vessia G
Published: April 2021

The paper focuses on two-dimensional (2D) analyses of a bridge abutment based on a spatially variable soil. The analysis was carried out to evaluate the settlement of the bridgehead. The numerical model consists of a reinforced concrete support structure, embankment and natural soil. Moreover, frictional contact between the soil and the structure is assumed. As it is well known, the natural soils are spatially highly variable materials, and their mechanical and physical parameters in geotechnical designing, such as a bridge abutment, must be considered variable. Thus, the presented analyses will be devoted to determining the settlement of the structure under study, in probabilistic terms due to soil variability. To this end, Sequential Gaussian Simulation was used to describe the spatial variability of soil parameters. This approach uses geostatistical methods to produce different realizations of soil parameters. A data set of several Cone Penetration Tests (CPT) was used. Simulations were used to calculate the histogram of a bridgehead settlement and search the worst case. Abaqus program and some ad hoc scripts written in Python language were used to perform the analyses. The analysis reflects several stages of abutment’s construction. This allows for a comprehensive analysis of a bridge abutment.
Investigation on the rotational bedding of king piles on the basis of model tests
Authors: Beuße Jannik , Grabe Jürgen
Published: April 2021

Rising world trade and the following consolidation of material flows cause a growing need for bigger bulk carriers. Therefore, the quay walls of the harbours need to be adjusted to realize the depth of the channels. Combined sheet pile walls are used to build quay walls. They consist out of up to 45 m long H-shaped beams and Z-shaped intermediate piles. As a result of the loads, which cause normal forces and bending moments, the stability of the slender profiles is endangered, whereby the deflection of the profile head and the embedding in the soil plays an important role. With the introduction of the standards of DIN EN 1993-5:2010-12 [1] in connection with DIN EN 1993-1-1:2010-12 [2] the proofing of combined walls needs to be done under combination of the resistance against flexural buckling and lateral-torsional buckling. For that reason the rotational resistance of the soil must be considered in order to ensure an economical design. The rotational bedding in cohesive soil is different from that in noncohesive soil and was investigated by laboratory tests as well as by numerical simulations. The results of a FOSTA / aif project with the goal of optimizing the stability procedure of combined walls are be presented.
Investigations of Soil Plugging in Open-Ended Piles with Respect to the Long-Term Behaviour of the Plug
Authors: Henke Sascha
Published: April 2021

Soil plug formation in open-ended piles can lead to a significant increase in bearing capacity as well as in driving resistance. Therefore, it is of main interest to predict the tendency of soil plug formation with respect to the pile geometry, the installation method as well as the penetration depth. In the present paper, the results from in-site testing as well as centrifuge testing are presented. The results are discussed mainly focussing on the tendency of soil plug formation with respect to the above mentioned factors. Furthermore, the results of long term in-site measurements of the earth-pressure at a tubular pile’s toe are evaluated showing that the soil plug remains stable over a period of more than one year although the pile was subjected to loading due to traffic, waves as well as tidal water changes.
Antemortem vs Postmortem Histopathologic and Ultrastructural Findings in Paired Transbronchial Biopsy Specimens and Lung Autopsy Samples From Three Patients With Confirmed SARS-CoV-2
Authors: Gagiannis Daniel , Umathum Vincent Gottfried , Bloch Wilhelm , Rother Conn , Stahl Marcel , Witte Hanno Maximilian , Djudjaj Sonja , Boor Peter , Steinestel Konrad
Published: April 2021

Objectives

Respiratory failure is the major cause of death in coronavirus disease 2019 (COVID-19). Autopsy-based reports describe diffuse alveolar damage (DAD), organizing pneumonia, and fibrotic change, but data on early pathologic changes and during progression of the disease are rare.

Methods

We prospectively enrolled three patients with COVID-19 and performed full clinical evaluation, including high-resolution computed tomography. We took transbronchial biopsy (TBB) specimens at different time points and autopsy tissue samples for histopathologic and ultrastructural evaluation after the patients’ death.

Results

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed by reverse transcription polymerase chain reaction and/or fluorescence in situ hybridization in all TBBs. Lung histology showed reactive pneumocytes and capillary congestion in one patient who died shortly after hospital admission with detectable virus in one of two lung autopsy samples. SARS-CoV-2 was detected in two of two autopsy samples from another patient with a fulminant course and very short latency between biopsy and autopsy, showing widespread organizing DAD. In a third patient with a prolonged course, autopsy samples showed extensive fibrosis without detectable virus.

Conclusions

We report the course of COVID-19 in paired biopsy specimens and autopsies, illustrating vascular, organizing, and fibrotic patterns of COVID-19–induced lung injury. Our results suggest an early spread of SARS-CoV-2 from the upper airways to the lung periphery with diminishing viral load during disease.
Understanding Breast Implant Illness: Etiology is the Key
Authors: Yang Siling , Klietz Marie-Luise , Harren Anna Katharina , Wei Qiang , Hirsch Tobias , Aitzetmüller Matthias M
Published: April 2021

Because breast augmentation is one of the most popular cosmetic procedures, the issue of implant-related complications has been widely debated ever since the FDA approved the use of implants in 1962. Although decades have passed, breast implant illness (BII) still represents a poorly defined and controversial complication. With ongoing nonscientific discussion in the mainstream media and on social media, revealing the etiology of BII is urgent because knowledge of this subject ultimately influences patients’ decisions. Little or no scientific research is currently available on BII and no final conclusions regarding its etiology, clinical manifestations, diagnostic criteria, or treatment have been made. This review aims to give an overview of the hypotheses on the etiology of BII and seeks inspiration to improve the conditions of BII patients.
Exorcising Race and Empire from American Nature Conservation
Authors: Sarkar Sahotra
Published: April 2021

This viewpoint chronicles the history of racial and imperial bias in American environmentalism and sketches a way for a better future.
Using hair cortisol analysis to understand the biological factors that affect black-footed ferret (Mustela nigripes) stress physiology
Authors: Santymire R M , Ali N , Marinari P E , Livieri T M
Published: April 2021

The black-footed ferret (Mustela nigripes) was driven to near extinction due to habitat loss and an introduced disease, sylvatic plague (Yersinia pestis). After 35 years of breeding in ex situ facilities, the black-footed ferret has been experiencing infertility with seminal traits declining in males and only about a third of breeding-aged females are whelping. Our goal was to use hair cortisol analysis to determine if the ex situ population was experiencing chronic stress that was affecting reproduction by comparing captive ferrets to wild individuals. Our specific objectives were to (i) compare hair cortisol concentrations (HCCs) between age classes (juveniles versus adults), (ii) compare the HCCs of in situ and across different ex situ facilities and (iii) determine the relationship between HCCs and reproductive success. Overall, wild juveniles had higher HCC than wild adults. Our generalized linear mixed model determined that the parameters that best predict HCC for adults were the interactions among sex, in situ versus ex situ facilities and season. During both seasons, wild females had higher HCCs compared to the ex situ females. During the breeding season, male HCCs across breeding facilities varied and males at the breeding facility with the largest ferret habitats had HCCs similar to wild males. At one breeding facility, HCC was higher in males that sired compared to those that did not sire. In conclusion, ex situ ferrets do not have higher HCC than wild individuals when controlling for season and ex situ habitat size, and ex situ males with higher HCC tended to sire. This suggests that HCC may be metabolically driven and/or that low HCC may be an indication of hypothalamus–pituitary–adrenal axis dysregulation and warrants further investigation both for laboratory validation and biological relevance.
For ‘Common Christianity’: War, Peace and the Campaign of the Irish Recruiting Council, 1918
Authors: Maartens Brendan
Published: April 2021

Established towards the end of the Great War, the Irish Recruiting Council was responsible for one of the largest military recruitment campaigns ever waged on Irish soil. Tasked with raising 50,000 volunteers, it produced a wide array of promotional material which included posters, newspaper advertisements and a fortnightly magazine entitled The Irish Soldier. Its work has attracted a measure of scholarly attention, but little is known about its origins, its dealings with authorities in Westminster and Dublin Castle, and the operational difficulties it encountered when attempting to mobilise the public. Even less is known about its newspaper campaign and the reasons behind the continuation of the body in peacetime, when the need for recruits had apparently subsided. This paper addresses these shortcomings by examining the IRC in more detail than has hitherto been achieved in the historiography. In so doing, it calls for a revision of existing understandings of the Council, suggesting that it was not just a recruiting body per se, but a major propaganda agency which portrayed enlistment as a means of uniting a divided country and encouraged Irishmen to mobilise to help resolve long-standing tensions between nationalists and unionists.
Nurr1 repression mediates cardinal features of Parkinson’s disease in α-synuclein transgenic mice
Authors: Argyrofthalmidou Maria , Spathis Athanasios D , Maniati Matina , Poula Amalia , Katsianou Maira A , Sotiriou Evangelos , Manousaki Maria , Perier Celine , Papapanagiotou Ioanna , Papadopoulou-Daifoti Zeta , Pitychoutis Pothitos M , Alexakos Pavlos , Vila Miquel , Stefanis Leonidas , Vassilatis Demetrios K
Published: April 2021

Duplication/triplication mutations of the SNCA locus, encoding alpha-synuclein (ASYN), and loss of function mutations in Nurr1, a nuclear receptor guiding midbrain dopaminergic neuron development, are associated with familial Parkinson’s disease (PD). As we age, the expression levels of these two genes in midbrain dopaminergic neurons follow opposite directions and ASYN expression increases while the expression of Nurr1 decreases. We investigated the effect of ASYN and Nurr1 age-related expression alterations in the pathogenesis of PD by coupling Nurr1 hemizygous with ASYN(s) (heterozygote) or ASYN(d) (homozygote) transgenic mice. ASYN(d)/Nurr1+/− (2-hit) mice, contrary to the individual genetic traits, developed phenotypes consistent with dopaminergic dysfunction. Aging ‘2-hit’ mice manifested kyphosis, severe rigid paralysis, L-DOPA responsive movement impairment and cachexia and died prematurely. Pathological abnormalities of phenotypic mice included SN neuron degeneration, extensive neuroinflammation and enhanced ASYN aggregation. Mice with two wt Nurr1 alleles [ASYN(d)/Nurr1+/+] or with reduced ASYN load [ASYN(s)/Nurr1+/−] did not develop the phenotype or pathology. Critically, we found that aging ASYN(d), in contrast to ASYN(s), mice suppress Nurr1-protein levels in a brain region–specific manner, which in addition to Nurr1 hemizygosity is necessary to instigate PD pathogenesis. Our experiments demonstrate that ASYN-dependent PD-related pathophysiology is mediated at least in part by Nurr1 down-regulation.
How Internet Access Drives Global Vaccine Skepticism
Authors: Lunz Trujillo Kristin , Motta Matthew
Published: April 2021

Counterintuitively, wealthier countries tend to be more vaccine skeptical than poorer countries. One possible explanation—the Online Accessibility hypothesis—posits that internet access facilitates the spread of antivaccine misinformation, particularly for those lower in scientific and medical expert trust. Another explanation—the Out of Sight hypothesis—is that some citizens in richer countries fail to consider the risks of vaccine-preventable diseases because they are rarely experienced directly. Merging country-level data with nationally representative survey data (N = 149,014) from 144 countries, we find evidence for the Online Accessibility hypothesis. These findings are robust to alternate measures of wealth and modeling strategies.
Lipopolysaccharide endotoxin injections elevated salivary TNFα and corneal temperatures and induced dynamic changes in circulating leukocytes, inflammatory cytokines, and metabolic indicators in wether lambs
Authors: Cadaret Caitlin N , Abebe Marytza D , Barnes Taylor L , Posont Robert J , Yates Dustin T
Published: April 2021

Pathogenic infections increase morbidity and reduce performance in livestock, and thus understanding the comprehensive physiological changes associated with infections can benefit production sustainability. In this study, we sought to investigate such physiological responses to an acute immune challenge in lambs. Polypay wethers received single IV injections of 1.5 µg/kg lipopolysaccharide endotoxin (LPS-injected; n = 6) or saline (controls; n = 6). Corneal temperatures (via infrared thermography), rectal temperatures, blood, plasma, and saliva were assessed every 2 hr for 10 hr after injections. Blood was also assessed at 24 hr. LPS-injected lambs exhibited elevated (P < 0.05) corneal and rectal temperatures that peaked at 4 hr but were still slightly greater (P < 0.05) than controls at 10 hr. Circulating total white blood cells, monocytes, and granulocytes were reduced (P < 0.05) in LPS-injected lambs within the first 4 hr but were subsequently greater (P < 0.05) than in controls. Lymphocytes were reduced (P < 0.05) in LPS-injected lambs over the first 8 hr and did not differ from controls thereafter. Red blood cells, hematocrit, and hemoglobin were increased (P < 0.05) in LPS-injected lambs over the first 6 hr, indicating mild dehydration. Blood glucose briefly increased (P < 0.05) in LPS-injected lambs at 2 hr but was less (P < 0.05) than in controls thereafter. Blood lactate was greater (P < 0.05) in LPS-injected lambs between 6 and 10 hr after injections, which together with reduced (P < 0.05) CO2 partial pressure indicated a metabolic shift toward glycolysis. LPS-injected lambs exhibited a transient increase (P < 0.05) in plasma TNFα at 2 and 4 hr only and sustained increases (P < 0.05) in CXCL9 and CXCL10 beginning at 6 and 4 hr, respectively. They also exhibited a mild, paradoxical increase (P < 0.05) in the anti-inflammatory sFRP3. Salivary TNFα was increased (P < 0.05) in LPS-injected lambs at 2 hr only. Regression analyses indicated that rectal temperatures were a generally poor predictor of the other inflammatory components in this study, with the exception of circulating leukocyte populations. Likewise, correlations among the 10 cytokines measured in this study were generally weak, with notable exceptions between CXCL9 and CXCL10 and between IL-21 and IFNγ. These findings demonstrate that physiological changes to even short-lived immune challenges are dynamic in nature and persist beyond the time frame of febrile responses and other common assessments.
Two New Species of Chiggers (Trombidiformes: Trombiculidae) From Brazil
Authors: Bassini-Silva Ricardo , Welbourn Cal , Ochoa Ron
Published: April 2021

Chigger mites are parasites of terrestrial vertebrates, including humans. Here, we describe two new species belonging to the American genera Colicus Brennan and Parasecia Loomis. Both species were described on the base of museum specimens originated from Minas Gerais State, Brazil, Colicus barrosbattestiae n. sp. parasitizing the rodent, Oligoryzomys fornesi and Parasecia jacinaviciusi n. sp. parasitizing the marsupial, Monodelphis domestica.
Atraumatic Vertebral Artery Dissection in a Patient With a Migraine Headache
Authors: Lloyd Michael L , Billingslea Samuel , Slama Richard
Published: April 2021

This case discusses a 34-year-old active duty male who presented to the emergency department with a 2-week persistent headache. His initial review of symptoms was reassuring until a detailed neurologic examination on his second visit revealed a visual deficit in the left upper quadrant. Additionally, he complained of intermittent tension headaches for the last several years but had no history of diagnosed migraines until he was seen 4 days prior for empiric migraine therapy in the same emergency department and left without improvement in symptoms. On his return visit, computerized tomography scan with intravenous contrast revealed a left vertebral artery dissection and hematoma. The patient was admitted for medical management and subsequently found to have suffered a small infarction of right lingual gyrus cortex on magnetic resonance imaging. This case illustrates the importance of maintaining a broad differential diagnosis and high index of suspicion in the patient with new focal neurologic findings in order to diagnose a potentially fatal disease.
Slow chromatin dynamics enhances promoter accessibility to transcriptional condensates
Authors: Yamamoto Tetsuya , Sakaue Takahiro , Schiessel Helmut
Published: April 2021

Enhancers are DNA sequences at a long genomic distance from target genes. Recent experiments suggest that enhancers are anchored to the surfaces of condensates of transcription machinery and that the loop extrusion process enhances the transcription level of their target genes. Here, we theoretically study the polymer dynamics driven by the loop extrusion of the linker DNA between an enhancer and the promoter of its target gene to calculate the contact probability of the promoter to the transcription machinery in the condensate. Our theory predicts that when the loop extrusion process is active, the contact probability increases with increasing linker DNA length. This finding reflects the fact that the relaxation time, with which the promoter stays in proximity to the surface of the transcriptional condensate, increases as the length of the linker DNA increases. This contrasts the equilibrium case for which the contact probability between the promoter and the transcription machineries is smaller for longer linker DNA lengths.
Characteristics of diffuse hemispheric gliomas, H3 G34-mutant in adults
Authors: Picart Thiébaud , Barritault Marc , Poncet Delphine , Berner Lise-Prune , Izquierdo Cristina , Tabouret Emeline , Figarella-Branger Dominique , Idbaïh Ahmed , Bielle Franck , Bourg Véronique , Vandenbos Fanny Burel , Moyal Elizabeth Cohen-Jonathan , Uro-Coste Emmanelle , Guyotat Jacques , Honnorat Jérôme , Gabut Mathieu , Meyronet David , Ducray François
Published: April 2021

Background

Diffuse hemispheric gliomas, H3 G34-mutant (DHG H3G34-mutant) constitute a distinct type of aggressive brain tumors. Although initially described in children, they can also affect adults. The aims of this study were to describe the characteristics of DHG H3G34-mutant in adults and to compare them to those of established types of adult WHO grade IV gliomas.

Methods

The characteristics of 17 adult DHG H3G34-mutant, 32 H3.3 K27M-mutant diffuse midline gliomas (DMG), 100 IDH-wildtype, and 36 IDH-mutant glioblastomas were retrospectively analyzed.

Results

Median age at diagnosis in adult DHG H3G34-mutant was 25 years (range: 19–33). All tumors were hemispheric. For 9 patients (56%), absent or faint contrast enhancement initially suggested another diagnosis than a high-grade glioma, and diffusion-weighted imaging seemed retrospectively more helpful to suspect an aggressive tumor than MR-spectroscopy and perfusion MRI. All cases were IDH-wildtype. Most cases were immunonegative for ATRX (93%) and Olig2 (100%) and exhibited MGMT promoter methylation (82%). The clinical and radiological presentations of adult DHG H3G34-mutant were different from those of established types of adult grade IV gliomas. Median overall survival of adult DHG H3G34-mutant was 12.4 months compared to 19.6 months (P = .56), 11.7 months (P = .45), and 50.5 months (P = .006) in H3.3 K27M-mutant DMG, IDH-wildtype, and IDH-mutant glioblastomas, respectively.

Conclusions

Adult DHG H3G34-mutant are associated with distinct characteristics compared to those of established types of adult WHO grade IV gliomas. This study supports considering these tumors as a new type of WHO grade IV glioma in future classifications.
An overview of speciation and species limits in birds
Authors: Winker Kevin
Published: April 2021

Accurately determining avian species limits has been a challenge and a work in progress for most of a century. It is a fascinating but difficult problem. Under the biological species concept, only lineages that remain essentially independent when they are in sympatry are clearly species. Otherwise, there is no clear line yet found that marks when a pair of diverging lineages (e.g., in allopatry) become different enough to warrant full biological species status. Also, with more data, species limits often require reevaluation. The process of divergence and speciation is itself very complex and is the focus of intense research. Translating what we understand of that process into taxonomic names can be challenging. A series of issues are important. Single-locus criteria are unlikely to be convincing. Genetic independence is not a species limits requirement, but the degree of independence (gene flow) needs to be considered when there is opportunity for gene flow and independence is not complete. Time-based species (limits determined by time of separation) are unsatisfactory, though integrating time more effectively into our datasets is warranted. We need to disentangle data signal due to neutral processes vs. selection and prioritize the latter as the main driver of speciation. Assortative mating is also not likely to be an adequate criterion for determining species limits. Hybridization and gene flow are more important than ever, and there is a condition not being treated evenly in taxonomy: evolutionary trysts of 2 or more lineages stuck together through gene flow just short of speciation over long periods. Comparative methods that use what occurs between good species in contact to infer species limits among allopatric forms remain the gold standard, but they can be inaccurate and controversial. Species-level taxonomy in birds is likely to remain unsettled for some time. While the study of avian speciation has never been more exciting and dynamic, there is no silver bullet for species delimitation, nor is it likely that there will ever be one. Careful work using integrative taxonomy in a comparative framework is the most promising way forward.
“Reasonable” Force at the U.S.-Mexico Border
Authors: Vega Irene I
Published: April 2021

While social scientists have studied the relationship between police culture and use of force for decades, federal immigration agents have been left out of these analyses. Addressing this gap is urgent given patterns of excessive force at the militarized U.S.-Mexico border. Drawing on bureaucratic documents and interviews with active Border Patrol agents, this article examines the culture of force within this organization. I show that the Border Patrol produces a sense of exceptional threat and power among agents through 1) narratives that construct the border as a uniquely dangerous work environment, and 2) lessons that encourage an overly-individualistic view of reasonableness, the constitutional standard that governs police force in the United States. Together, these organizational messages foster in agents a disproportionate sense of threat coupled with an awareness of the low probability of legal sanction for force violations. This paradoxical combination of vulnerability and power undergirds agents’ conceptions of their force authority.
Taking Call
Authors: Aronowitz Shoshana V.
Published: April 2021

Telehealth proves to be more than just a stopgap in providing support to patients.
Immunity from Civil Liability, Part 2
Authors: Brous Edie
Published: April 2021

What nurses should understand in times of crisis.
COVID-19 and Our National ‘Moral Imperative’
Authors: Brown Theresa
Published: April 2021

A novel take on epidemic disease management.
Potent Topical Corticosteroids May Increase Osteoporosis, Fracture Risk
Authors: Rosenberg Karen
Published: April 2021

According to this study:

High cumulative use of potent and very potent corticosteroids is associated with an increased risk of osteoporosis and major osteoporotic fractures.
Diabetes Drug AIDS Weight Reduction in Adults
Authors: Rosenberg Karen
Published: April 2021

According to this study:

In adults who were obese or overweight, once-weekly subcutaneous semaglutide administration in addition to lifestyle interventions resulted in sustained, clinically relevant weight loss.
Ignorance has Turned COVID-19 Into a Social Stigma
Authors: Naeim Mahdi , Malekpour Azim , Rezaeisharif Ali
Published: April 2021

Because of the rapidly increasing number of coronavirus (COVID-19) patients, fears and worries have arisen because of lack of awareness and have led to challenges such as social stigma. Therefore, the present article aims to pay attention to the social stigma of people with a history of COVID-19. Because of the emergence of COVID-19 disease, accurate and complete information about its psychosocial problems is not available. According to the guidelines and strategies announced by the World Health Organization and the U.S. Centers for Disease Control and Prevention, it is important to review and present comprehensive programs based on community culture.
Gender Differences in a Sample of Egyptian University Students With Opioid Use Disorders Attributed to Tramadol
Authors: Bassiony Medhat M. , El-Deen Ghada Salah , Saad Abdallah , Abdelghani Mohamed
Published: April 2021

Background and Objective:

Tramadol use is an overwhelming problem in Egypt. Males and females who use tramadol differ in their sociodemographic and clinical profiles. The aim of this study was to identify gender differences in tramadol use in students at Zagazig University, Egypt.

Methods:

A cross-sectional study included a total of 1135 undergraduate students, aged 17 to 34 years, from both sexes; males (n=674, 59.4%) and females (n=461, 40.6%), from 10 colleges in Zagazig University. Respondents were randomly selected to assess their tramadol use utilizing the drug use disorders identification test (DUDIT) and the drug use disorders identification test-extended (DUDIT-E).

Results:

Tramadol use was more prevalent in male than female students (19.7% vs. 2.4%). Both smoking and alcohol use were shared predictive factors for tramadol use in both sexes. The mean years of education and cannabis use predicted tramadol use in males, while only mean age predicted tramadol use in females. Among tramadol users, males were more likely than females to be smokers, polysubstance, and cannabis users, and to have a positive attitude toward tramadol use.

Conclusions:

Tramadol use was common among university students, with higher prevalence among males. Sex-related similarities and differences were present. Results can guide health policymakers to develop appropriate prevention and management strategies. Population-based longitudinal studies are warranted to explore the causal relationship between tramadol use and progression to other substances in both sexes.