bluuebunny/crossref_metadata_2025 huggingface dataset:
Comment on ‘Forces on hockey players: vectors, work, energy and angular momentum Nina Nässén et al 2019 Eur. J. Phys.
40 065005’
Authors: Bracko Mike
Published: November 2020

Nässén et al (2019 Eur. J. Phys.
40 065005) are recommending a different hockey skating technique called ‘angular momentum skating’. The authors use examples of physics, and physics equations for work and energy of traditional forward skating strides. However, this information can be interpreted as a disguise for their different skating technique because the physics models and equations do not capitulate any justification for hockey players using their angular momentum skating technique. The authors suggestion to use an angular momentum skating technique is a judgement not founded on proof or certainty. They offer no objective proof, through physics equations or otherwise, that angular momentum skating has any benefits for hockey players to be faster, more efficient skaters.
Simple model of a standing vertical jump
Authors: L Lin Chris
Published: November 2020

In this paper we use Newton’s third law to deduce the simplest model of a system that can perform a standing vertical jump—a two-segmented object with an initial constant repulsive force between the segments, followed by an abrupt attractive force. Such an object, when placed on a sturdy ground, will jump, and the motion can be calculated using only the constant acceleration equations, making the example suitable for algebra-based physics. We then proceed to solve for the motion of an n-segmented object and determine the optimal number of segments for jumping. We then discuss a few similarities and differences of this simple model from jumping robots and jumping humans and conclude by arguing the model’s pedagogical merits.
Modelling of the magnetization reversal of nanocomposites consisting of core–shell particles
Authors: Erokhin Sergey G , Berkov Dmitry V
Published: November 2020

We performed large-scale micromagnetic simulations on core–shell particle systems for

S
r
F

e

12

O

19

/

F
e

and

C
o
F

e
2

O
4

/

C
o

nanocomposites, where both magnetically hard and soft materials were considered as the core or shell materials of these particles. A detailed analysis of the influence of structural properties and exchange core–shell coupling within the same particle on the magnetization reversal of a nanocomposite was carried out, revealing different remagnetization scenarios in terms of the evolution of magnetization distributions in soft magnetic cores. The optimal nanocomposite compounds with respect to the energy product of material were predicted.
IFM Nano Thruster performance studied by experiments and numerical simulations
Authors: Mühlich Nina Sarah , Seifert Bernhard , Aumayr Friedrich
Published: November 2020

Field emission electric propulsion thrusters are characterised by their low thrust range, which makes them ideal for the precise control of spacecraft. Decisive for precise control are the properties of the thruster ion beam, which includes the beam divergence angle and the thrust vector. The analysis of these properties is also necessary in order to be able to estimate the interactions of the beam with components of the spacecraft. Due to such interactions, solar panels or electrical instruments on board the spacecraft could be damaged by sputtering effects.

The spatial ion current density and energy distribution of a test crown emitter beam, with different specifications compared to the IFM Nano thruster, were examined experimentally with a diagnostic system, including Faraday cups and a retarding potential analyser. In addition to the analysis of the beam profile of an emitting crown, a single emitting needle was analysed. Based on these experimental analyses, an ion trajectory simulation model was developed to determine the theoretical ion current density distribution. This model includes the properties of a liquid metal ion source, where the ion trajectories start from their point of origin, the so-called Taylor cone jet cap. The benchmark of the model shows that the thrust vector and divergence angle correspond to the experimental results and shows the identical calculations for different thruster parameters, like emission current and electrode voltage. The simulation allows for the optimisation of existing and novel thruster geometries in terms of performance, reliability and longevity.
Analysing the charged scalar boson contribution to the charged-current B meson anomalies
Authors: Cardozo Jonathan , Muñoz J H , Quintero Néstor , Rojas Eduardo
Published: November 2020

Experimental measurements collected by the BABAR, Belle, and LHCb experiments on different observables associated with the semileptonic transition

b
→
c
τ

ν

̄

τ

, indicate the existence of disagreement respect with the Standard Model predictions. We analyze the charged scalar boson contributions to these charged-current B meson anomalies within the framework of two Higgs doublet model (2HDM) with the most general Yukawa couplings to quarks and leptons from the third generation, involving left-handed and right-handed (sterile) neutrinos. We perform a phenomenological study of the Yukawa couplings parameter space that accommodates these anomalies. We consider the most recent data from HFLAV world-average and Belle combination, and the upper limits

BR

(

B

c

−

→

τ

−

ν

̄

τ

)

<
30
%

and 10%. In addition, we include in our study the prospect measurements on R(D
(*)) that the Belle II experiment could achieve and explore, for the first time, the future implications for the corresponding charged scalar Yukawa couplings. This analysis updates the existing literature and includes new important observables. Our results show that current experimental

b
→
c
τ

ν

̄

τ

data and Belle II projection favor the interpretation of a charged scalar boson interacting with right-handed neutrinos. Furthermore, as a side analysis regarding the charged scalar boson interpretation, we revisit the relation between R(D*) and

BR

(

B

c

−

→

τ

−

ν

̄

τ

)

by investigating whether the claim that pseudoscalar new physics interpretations of R(D*) are implausible due to the B

c
lifetime is still valid, to the light of the recent data and Belle II prospects on R(D*). Lastly, we reexamine addressing the R(D
(*)) anomalies in the context of the 2HDM of type II. We show that with the current Belle combined data is possible to obtain an available parameter space on the plane

(

M

H

±

,
tan

β

)

for a simultaneous explanation of the anomalies, in consistency with

B
→
τ

ν

̄

τ

and bounds from inclusive radiative B decays. Moreover, projections at the Belle II experiment suggest that the 2HDM of type II would be no longer disfavored.
Pyroelectric ultrasound sensor model: directional response
Authors: Kaupinmäki Santeri , Cox Ben , Arridge Simon , Baker Christian , Sinden David , Zeqiri Bajram
Published: November 2020

Ultrasound is typically measured using phase-sensitive piezoelectric sensors. Interest in phase-insensitive sensors has grown recently, with proposed applications including ultrasound attenuation tomography of the breast and acoustic power measurement. One advantage of phase-insensitive detectors, in contrast to conventional phase-sensitive detectors, is that they do not suffer from a narrow directional response at high frequencies due to phase cancellation. A numerical model of a phase-insensitive pyroelectric ultrasound sensor is presented. The model consists of three coupled components run in sequence: acoustic, thermal, and electrical. The acoustic simulation models the propagation and absorption of the incident ultrasound wave. The absorbed acoustic power density is used as a heat source in the thermal simulation of the time-evolution of the temperature in the sensor. Both the acoustic and thermal simulations are performed using the k-Wave MATLAB toolbox with an assumption that shear waves are not supported in the medium. The final component of the model is a pyroelectric circuit model which outputs the sensor response based on the temperature change in the sensor. The modelled pyroelectric sensor response and directional dependence are compared to empirical data.
FDTD method study on the effects of geometric parameters on the W- Al2O3 nano-structure thermal emitter
Authors: Lyu Jizu , Cui Guicheng , Shi Lin , Gao Linsong , Bai Minli , Jiang Lei
Published: November 2020

In this paper, a 2D periodic structure made of tungsten (W) grating patch on a thin Al2O3 spacer and an opaque W film is proposed, as a broadband selective thermal emitter. We numerically investigated the spectral emissivity of the structure from the deep by finite-difference time-domain method. Geometric parameters effects on the emissivity are discussed and the mechanisms of magnetic polaritons in the structure are further analyzed in detail. In addition, by adding another metal-dielectric stack upon the pre-existing grating structure, the emissivity of the composite structure can be further enhanced, and the normal emissivity exceeds 0.95 in the wavelength range of 0.65–1.95 μm, some even close to unity. Furthermore, the composite structures are found to exhibit insensitivity to polar angle and polarization.
Large scale production of superparamagnetic iron oxide nanoparticles by the haloarchaeon Halobiforma sp. N1 and their potential in localized hyperthermia cancer therapy
Authors: Salem Nayera F A , Abouelkheir Samia S , Yousif Asmaa M , Meneses-Brassea Bianca P , Sabry Soraya A , Ghozlan Hanan A , El-Gendy Ahmed A
Published: November 2020

Magnetic iron oxide nanoparticles are among metal nanoparticles that attract huge attention in many biotechnological fields especially in the biomedical area. Their extensive capabilities and easy separation methodology drive them to be an interesting point to many researchers. Biosynthesis is of a major importance among different methods of nanoparticles production. Microbial synthesis of these nanoparticles by bacteria and yeasts have been reported on a wide scale. However, biosynthesis using halophilic archaea is still in an early stage. This study reveals the first contribution of the haloarchaeon Halobiforma sp. N1 to the nanobiotechnology field. It reports a rapid and economical one-step method of fabricating functionalized superparamagnetic iron oxide nanoparticles and their feasibility for hyperthermia treatment for cancer therapy. Herein, we have focused on optimizing the quantity of these fascinating nanoparticles, obtaining a very high yield of 15 g l−1 with high dispersion in water solution. Their unique characteristics enable them to participate in medical applications. They are nearly spherical in shape with a high degree of homogenity and uniformity with average diameter of 25 ± 9 nm. Also, the magnetic properties and elemental structure of the formed nanoparticles tend to be superparamagnetic like behavior with saturation magnetization of 62 emu g−1 and purity of 98.38% of iron oxide, respectively. The specific absorption rate (SAR) was measured and the particles induced significant heating power at lower frequencies which is a promising result to be applied for in vitro/in vivo hyperthermia studies in the near future.
Decoupling ion energy and flux in intermediate pressure capacitively coupled plasmas via tailored voltage waveforms
Authors: Doyle Scott J , Gibson Andrew R , Boswell Rod W , Charles Christine , Dedrick James P
Published: November 2020

The discrete control of ion energy and flux is of increasing importance to industrially relevant plasma sources. The ion energy distribution functions (IEDFs) and net ion flux incident upon material surfaces in intermediate pressure (≈133 Pa, 1 Torr) radio-frequency capacitively coupled plasmas (rf CCPs) are coupled to the spatio-temporal sheath dynamics and resulting phase-averaged sheath potential. For single frequency driven discharges this co-dependence of ion energy and flux on the sheath potential limits the range of accessible operating regimes. In this work, experimentally benchmarked 2D fluid/Monte-Carlo simulations are employed to demonstrate quasi-independent control of the ion flux and IEDF incident upon plasma facing surfaces in a collisional (≈200 Pa, 1.5 Torr argon) rf hollow cathode discharge driven by multi-harmonic (n ⩾ 2) tailored voltage waveforms. The application of variable phase offset n = 5 tailored voltage waveforms affords a significant degree of control over the ion flux

Γ

A
r

+

and mean ion energy

ϵ

̂

A
r

+

, modulating each by factors of 2.9 and 1.6, respectively as compared to 1.8 and 1.6, achieved via n = 2 dual-frequency voltage waveforms. The disparate modulations achieved employing n = 5 tailored voltage waveforms demonstrate a significant degree of independent control over the mean ion energy and ion flux for collisional conditions, enabling access to a wider range of operational regimes. Maximising the extent to which ion energy and flux may be independently controlled enables improvements to plasma sources for technological applications such as plasma assisted material manufacture and spacecraft propulsion.
Propagation of positive discharges in an air bubble having an embedded water droplet
Authors: Ning Wenjun , Lai Janis , Kruszelnicki Juliusz , Foster John E , Dai Dong , Kushner Mark J
Published: November 2020

Low temperature plasmas generated inside gas bubbles immersed in water is an effective method of rapidly transferring plasma generated reactive species to the water for applications in biomedicine, agriculture and environment. Reactive species are generally produced in the gas phase plasma and then solvate into the liquid. The large surface-to-volume ratio (SVR) of the bubble accelerates this process. In generating bubbles in water, aerosols and droplets are also contained within the bubble. These droplets also have a large SVR and so can be rapidly plasma activated. However, the presence of the droplets can also impact the propagation of the plasma in the bubble. In this paper, results are discussed from computational and experimental investigations of the formation and evolution of discharges in an air bubble immersed in water with an embedded water droplet. The computations were performed with a two-dimensional plasma hydrodynamics model. Experiments were performed with a quasi-2D bubble apparatus. In bubbles having a droplet, a plasma filament typically bridges from the powered electrode to the droplet, and then from the droplet to the bubble surface. A surface-hugging streamer also occurs on the inner bubble surface and on the surface of the droplet. Both surface streamers result in part from surface charge accumulation and can dominate the formation of reactive species that transport into the droplet. Increasing droplet conductivity suppresses propagation of the surface discharge and leads to a lower density of aqueous reactive species. Increasing conductivity of the surrounding water does not change the overall structure of the discharge but does slightly elevate the discharge intensity. The size and shape of the embedded droplet can significantly affect the formation and propagation of the streamer.
Negative differential resistance characteristics of GaN-based resonant tunneling diodes with quaternary AlInGaN as barrier
Authors: Yang Wen-Lu , Yang Lin-An , Zhang Xiao-Yu , Li Yang , Ma Xiao-Hua , Hao Yue
Published: November 2020

AlInGaN lattice-matched to GaN is proposed as a barrier for double-barrier single quantum well structure resonant tunneling diodes (RTDs), and it achievesnearly strain-free RTD with low In composition and thereby relatively high manufacturability. Compared with the lattice-matched ternary Al0.83In0.17N/GaN RTD, three lattice-matched InAlGaN/GaN RTD samples exhibit peak current density J
P over 20 times larger than that of the lattice-matched ternary RTD in numerical simulations. Simultaneously, two shallow defect levels (E
1 = 0.351 eV, E
2 = 0.487 eV) are considered at the RTD heterointerface to reveal the I–V characteristics under different defect densities. Negative differential resistance characteristics of the three quaternary RTDs are still available even though the defect density is up to ∼1018 cm−3, while that of the lattice-matched ternary RTD almost disappears when the defect density is ∼1017 cm−3 as a result of the lager ionization rate. Further, we introduce a deep-level defect E
t = 1 eV at the heterointerface and perform multiple forward voltage sweeps. Simulations show that the quaternary RTD samples have better reproducibility in spite of the defect density being 100 times larger than that of the lattice-matched ternary RTD. This work illustrates that InAlGaN can provide greater flexibility for the design and fabrication of GaN-based RTDs.
A machine learning workflow for 4D printing: understand and predict morphing behaviors of printed active structures
Authors: Su Jheng-Wun , Li Dawei , Xie Yunchao , Zhou Thomas , Gao Wenxin , Deng Heng , Xin Ming , Lin Jian
Published: November 2020

Understanding and predicting morphing response of printed active structures remain a challenge in 4D printing. To tackle it, in this paper, we present a consolidated data-driven approach enabled by an ensemble of machine learning (ML) algorithms. First, three ML algorithms were employed to quantitatively correlate a geometrical feature (thickness) with the final morphing shapes indicated by curvatures and curving angles. Among them, the gradient boosting algorithm achieved correlation factors (R
2) of 0.96 and 0.94 when predicting the curvatures and curving angles by using the data collected from 150 experiments. The random forest model enabled to rank the importance of fabrication parameters in determining the shape morphing behaviors. To forecast the dynamic response of printed structures, three time series forecast algorithms were implemented based on the time-dependent image data during morphing processes of the printed active structures. Among them, the exponential smoothing method achieved an average mean absolute percentage error of 0.0139. This work offers a proof-of-concept on how the ensemble ML algorithms can be employed to delineate and predict morphing mechanism of printed active structures, thus providing a new paradigm for advancing the state-of-the-art research in 4D printing.
Effects of functional alkali in magnetorheological finishing fluid
Authors: Zhang Yunfei , Fang Fengzhou , Wang Lili , Li Xiaoyuan , Liu Jiabao , Ye Zuoyan , Tian Dong , Huang Wen , Yu Miao , Ye Minheng , Wang Chao
Published: November 2020

Magnetorheological (MR) fluids can be utilized for ultra-precise finishing, for instance, in fused silica (FS) optics in giant laser system. However, few modification methods of MR fluid can improve the material removal rate (MRR) and surface quality of the finished optics simultaneously. In this study, we investigated the application of functional alkali additives in MR finishing fluid. MRR was doubled over the untreated MR fluid; meanwhile the surface roughness of the FS converged to 0.44 nm. Such excellent finishing performance can be mainly attributed to the dual functional effects of the triethanol amine (TEA) alkali, the hydroxides released by TEA contributes to the MRR increase and the steric hindrance effect of the ethanol ligands helps improve the surface quality.
Convergence to the traveling wave solution of a biological-physical model through a differential equation with piecewise constant argument
Authors: Ramirez-Carrasco C , Duque-Marín F
Published: November 2020

Getting to know explicitly or approximately the traveling wave solutions of the diffusive delay logistic equation, commonly known as the delayed Kolmogorov-Petrovsky-Piscounov-Fisher equation, is of major importance for understanding various biological and physical phenomena. In this study, we discretize the delay argument of the equation that satisfies the traveling wave and we obtain a second order delay differential equation with piecewise constant argument. We prove the existence and uniqueness of a solution for the discretized equation, and then prove that this solution converges uniformly along the whole straight towards the traveling wave. The methodology posed is based on the upper and lower solutions technique along with the use of a monotone integral operator. Our results show that the technique we developed is another good method for approaching traveling wave solutions. In addition, we suggest that this method can be applied to other reaction-diffusion equations that model a wide range of biological, physical, and chemical phenomena.
Writer verification based on simple graphemes and extreme learning machine approaches
Authors: Vásquez A , Mora M , Aubin V , Salazar E , Barrientos R , Hernandez R , Vilches K
Published: November 2020

mTraditional literature presents complex biometric sources, descriptors, and classifiers to solve the writer’s verification problem. The simple graphemes have been studied recently considering classifiers such as multilayer perceptron, support vector machine and convolutional neural network, which allow a high level of performance but with high computational cost in the training. In this paper, we propose the use of extreme learning neural networks to verify the writer identity based on simple graphemes with the aim of achieve a better descriptor performance in a less training time. The proposal allows verify peoples identity through the analysis of handwritten text in order to fakes detect, authorship identification, fakes, threats and thefts in documents. The experimental results show that this type of classifiers achieve a rate of success greater to the 95% for all five characters in the problem addressed, but with significantly less training times than traditionally used techniques.
Periodic orbits in dynamic systems with Wien Bridge
Authors: González J R , Ardila J G , Correa G
Published: November 2020

The following document showed the state space system that governs the behavior of the Wien Bridge, which is an electronic oscillator that generates sinusoidal waves, through an amplifier fed back by a bridge composed of four resistors and two capacitors. Through the simulations carried out, the existence of periodic orbits was verified when this system operates in a stable state. For this, the limit cycles were studied by being able to determine the origin of the periodic oscillation in the circuit in areas very close to the point of stability by means of the focus-center-limit cycle bifurcation presented in the Poincaré-Bendixon Theorem.
Effect of heavy metals (Ni, Cu, Pb) doped ZnO on the nonlinear optical properties
Authors: Salah Abeer , Aboud Ahmed A , Saad A M
Published: November 2020

In this paper, the non-linear optical properties of undoped and doped ZnO thin films were investigated. The films were doped with Ni, Pb, and Cu. an increase in the refractive index against wavelength is apparent for all films up to a certain value of wavelength. Z scan technique is used for measuring the nonlinear optical parameters via open and closed aperture configurations. Third order nonlinear susceptibilities (χ
(3)) of samples were calculated. The sign of nonlinear refractive index (n2) of ZnO was changed from positive (self-focus) to negative (de-focus) upon metal doping. Doping ZnO with heavy metals changes the sign of nonlinearity although the nonlinear absorption coefficient (β) is positive for all samples; the doped materials behave as optical limiters at high intensity. These materials are promising for optoelectronic devices and optical limiting applications.
S-band electron spin resonance spectroscopy using a short-circuited coplanar waveguide resonator
Authors: Roy Subhadip , Nandi Anuvab , Das Pronoy , Mitra Chiranjib
Published: November 2020

In this work, we study the development of a coplanar waveguide (CPW) resonator and its use in an electron spin resonance (ESR) spectrometer. The CPW resonator is designed to operate in S-band (2-4 GHz), with a short circuit configuration leading to miniaturization. It is so constructed such that it has a characteristic impedance of 50 ohms. The resonator supports quasi-TEM mode of propagation owing to its uniplanar nature, demanding detailed electromagnetic simulation. The design parameters and the electromagnetic field distribution are obtained from the simulation. The resonator is fabricated using optical lithography with a rapid prototyping technique. The characteristic response of the resonator is measured by coupling it to a Vector Network Analyzer (VNA). The ESR absorption spectrum of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) is captured by using this resonator in reflection geometry. The microwave magnetic field distribution at the sample position is investigated. The ascertained value of Lande g-factor is consistent with that reported in the literature. Spin sensitivity of the order of 1015 spins/gauss is achieved upon using this resonator at room temperature. The quality factor of this resonator is found to be low and this makes it suitable for use in a Pulsed ESR spectrometer.
Gestational and Postpartum Weight Trajectories Among Women With and Without Asthma
Authors: Stevens Danielle R , Grobman William , Kumar Rajesh , Lipsky Leah M , Hinkle Stefanie N , Chen Zhen , Williams Andrew , Rohn Matthew C H , Kanner Jenna , Sherman Seth , Mendola Pauline
Published: November 2020

Asthma leads to increased weight gain in nonpregnant populations, but studies have not examined this association within the context of pregnancy. The association between asthma and perinatal weight trajectories was examined in the Breathe—Wellbeing, Environment, Lifestyle, and Lung Function Study (2015–2019). Multilevel linear spline models were adjusted for age, race/ethnicity, income, marital status, education, cigarette smoking, parity, study site, and prepregnancy body mass index were used to examine differences in perinatal weight trajectories between women with (n = 299) and without (n = 101) asthma. Secondary analyses were conducted to assess whether associations differed by asthma phenotypes. At 40 weeks’ gestation, women with asthma gained 16.2 kg (95% confidence interval (CI): 14.6, 17.7) and women without asthma gained 13.1 kg (95% CI: 10.9, 15.4). At 3 months postpartum, women with asthma retained 10.4 kg (95% CI: 8.9, 11.9) and women without asthma retained 8.0 kg (95% CI: 5.9, 10.2). Among women with asthma, exercise-induced asthma and step 3 asthma medications were associated with excess gestational weight gain. These study findings suggest women with asthma gain and retain more weight during pregnancy and postpartum than do women without asthma.
Sex and Age Differences in Ambulatory Blood Pressure Monitoring Tolerability
Authors: Khaddage Sarah J , Patterson Julie A , Sargent Lana J , Price Elvin T , Dixon Dave L
Published: November 2020

BACKGROUND

Clinical practice guidelines endorse using ambulatory blood pressure monitoring (ABPM) for the diagnosis and management of hypertension. However, ABPM is not always tolerated by patients, and differences between individuals according to age and sex remain unexplored.

METHODS

This is a post hoc analysis of a prospective, single-arm clinical trial (NCT03920956) that evaluated the feasibility of an ABPM service provided at 2 community pharmacies. Tolerability was assessed using a previously published survey, which included 7 yes/no questions and 8 answered on a scale of 0–10. Descriptive statistics and Chi-square analyses were used to summarize the data for the patient surveys and to describe sex and age differences in device tolerability.

RESULTS

Of the 52 subjects enrolled, 50 (96%) completed the survey; half were female with a mean (SD) age of 57.5 years (15.8). Chi-square analyses showed that compared with their male counterparts, females were more likely to find the monitor cumbersome to wear (76.2% vs. 40%, P = 0.014). Subjects under 55 years of age were more likely to be disturbed by the noise of the monitor during driving (38.1% vs. 4.2%, P = 0.005) and at other times (35.0% vs. 8.3%, P = 0.029), and to find the monitor embarrassing to wear (33.3% vs. 7.1%, P = 0.019).

CONCLUSIONS

Although ABPM was generally well-tolerated overall, we did identify age and sex differences in tolerability. These factors should be considered to ensure patient acceptance and tolerability of ABPM.
Designing a microbiological monitoring program for compounding facilities
Authors: Tharp Jamie C , Kullar Rajkiran K , Tupps Matthew A
Published: November 2020

Purpose

We describe the evolution of a large multicenter health system’s microbiological monitoring program to improve standardization of viable sample collection practices; results review, interpretation, and response; and record keeping. We also describe lessons learned and considerations for other organizations considering microbiological monitoring program enhancements.

Developing a robust microbiological monitoring program requires policy and procedure development; training and education of staff involved in viable sample collection, results interpretation, and investigations; establishing a robust sampling plan; reviewing trend data; reviewing systems data; and conducting investigations. Well-defined policies and procedures ensure consistent response to “out of level” (ie, violative) sampling results. Staff education ensures staff involved in microbiological monitoring are educated on adequate sampling techniques and microbial contamination sources and mitigation strategies. Thorough record keeping is essential for microbiological monitoring sampling activities and ongoing systems monitoring. The records should include results, investigations, assessments, recommendations, and records of completed follow-up actions.

Conclusion

Facilities management requires a comprehensive microbiological monitoring and systems monitoring plan. In health systems with multiple sites, a centralized oversight and management program may be beneficial to standardize records, response planning, and overall control of controlled compounding environments.
Is Urinary Chromium Specific to Hexavalent Chromium Exposure in the Presence of Co-exposure to Other Chromium Compounds? A Biomonitoring Study in the Electroplating Industry
Authors: Martin Remy Aurélie , Robert Alain , Jacoby Nadège , Wild Pascal
Published: November 2020

Objectives

Electroplating processes are widely used in metal industries to improve the resistance properties of manufactured metal parts. Workers in this industry are potentially exposed both to hexavalent chromium (Cr(VI)) and to other chromium compounds [mostly trivalent chromium (Cr(III))], due to the use of chromic acid baths. The goal of this study was to validate urinary chromium as a Cr(VI) exposure biomarker in the presence of exposure to other chromium compounds.

Methods

A biomonitoring study consisted in monitoring airborne chromium exposure and urinary chromium for one working week in 93 workers from nine electroplating companies. Chromium concentrations were measured in all urinations of each volunteer for the working week. Individual airborne soluble and insoluble Cr(VI) as well as Cr(III) concentrations were measured for all of the shifts of the week. The main statistical analysis consisted in modelling, in a Bayesian framework, the pre- and post-shift urinary chromium as a function of airborne Cr(III) and airborne Cr(VI), taking into account the day of the week and the time of collection of the urines (pre- or post-shift).

Results

Preliminary descriptions showed an increase in pre-shift urinary chromium during the working week. The model showed an increase in urinary chromium over the shift related to the shift-specific airborne Cr(VI) concentration as well as an increasing trend over the week and a relationship with the mean weekly Cr(VI) thought to reflect chronic exposure. Taking into account the Cr(VI) exposure, there was no evidence of an effect of Cr(III) exposure on urinary chromium. A biological limit value (BLV) was derived from the French occupational exposure limit for Cr(VI) of 1 µg m−3 and was estimated at between 1.9 and 2.6 µg g−1 creatinine for a urinary sample collected at the end of the shift on the last working day of the week.

Conclusions

In the present context of mixed exposure to Cr(III) and Cr(VI) in electroplating, this study showed that urinary chromium depended only on airborne Cr(VI) concentrations, which justifies using a BLV for assessing workers’ exposure. The estimated BLV was close to the recommended French BLV, which is 1.8 µg g−1 creatinine, in the electroplating industry.
Dynamics in the expression of epigenetic modifiers and histone modifications in perinatal rat germ cells during de novo DNA methylation†
Authors: Rwigemera Arlette , El omri-Charai Rhizlane , Lecante Laetitia L , Delbes Geraldine
Published: November 2020

Epigenetic reprogramming during perinatal germ cell development is essential for genomic imprinting and cell differentiation; however, the actors of this key event and their dynamics are poorly understood in rats. Our study aimed to characterize the expression patterns of epigenetic modifiers and the changes in histone modifications in rat gonocytes at the time of de novo DNA methylation. Using transgenic rats expressing Green Fluorescent Protein (GFP) specifically in germ cells, we purified male gonocytes by fluorescent activated cell sorting at various stages of perinatal development and established the transcriptomic profile of 165 epigenetic regulators. Using immunofluorescence on gonad sections, we tracked six histone modifications in rat male and female perinatal germ cells over time, including methylation of histone H3 on lysines 27, 9, and 4; ubiquitination of histone H2A on lysine119; and acetylation of histone H2B on lysine 20. The results revealed the dynamics in the expression of ten-eleven translocation enzymes and DNA methyltransferases in male gonocytes at the time of de novo DNA methylation. Moreover, our transcriptomic data indicate a decrease in histone ubiquitination and methylation coinciding with the beginning of de novo DNA methylation. Decreases in H2AK119Ub and H3K27me3 were further confirmed by immunofluorescence in the male germ cells but were not consistent for all H3 methylation sites examined. Together, our data highlighted transient chromatin remodeling involving histone modifications during de novo DNA methylation. Further studies addressing how these dynamic changes in histone posttranslational modifications could guide de novo DNA methylation will help explain the complex establishment of the male germ cell epigenome.
‘Playing the Game’: Power, Authority and Procedural Justice in Interactions Between Police and Homeless People in London
Authors: Kyprianides Arabella , Stott Clifford , Bradford Ben
Published: November 2020

We explore the relevance of procedural justice theory for understanding the relationship between police and marginalized groups and individuals. Analysis is based on ethnographic research into the policing of the street population in an inner London borough through shadowing policing patrols and embedding observation within the homeless community. Police–street population relationships appear characterized by: (1) a structural context of extreme disempowerment; (2) a micro-sociological dimension relating to the exercise of authority and (3) a dynamic power relationship characterized by ‘the game of cat and mouse’. The nature of interactions within this context and the extreme marginality of the street population alter the weight placed on fairness perceptions and the extent to which police activity can affect legitimacy and compliance.
Three-dimensional analysis of synaptic organization in the hippocampal CA1 field in Alzheimer’s disease
Authors: Montero-Crespo Marta , Domínguez-Álvaro Marta , Alonso-Nanclares Lidia , DeFelipe Javier , Blazquez-Llorca Lidia
Published: November 2020

Alzheimer’s disease is the most common form of dementia, characterized by a persistent and progressive impairment of cognitive functions. Alzheimer’s disease is typically associated with extracellular deposits of amyloid-β peptide and accumulation of abnormally phosphorylated tau protein inside neurons (amyloid-β and neurofibrillary pathologies). It has been proposed that these pathologies cause neuronal degeneration and synaptic alterations, which are thought to constitute the major neurobiological basis of cognitive dysfunction in Alzheimer’s disease. The hippocampal formation is especially vulnerable in the early stages of Alzheimer’s disease. However, the vast majority of electron microscopy studies have been performed in animal models. In the present study, we performed an extensive 3D study of the neuropil to investigate the synaptic organization in the stratum pyramidale and radiatum in the CA1 field of Alzheimer’s disease cases with different stages of the disease, using focused ion beam/scanning electron microscopy (FIB/SEM). In cases with early stages of Alzheimer’s disease, the synapse morphology looks normal and we observed no significant differences between control and Alzheimer’s disease cases regarding the synaptic density, the ratio of excitatory and inhibitory synapses, or the spatial distribution of synapses. However, differences in the distribution of postsynaptic targets and synaptic shapes were found. Furthermore, a lower proportion of larger excitatory synapses in both strata were found in Alzheimer’s disease cases. Individuals in late stages of the disease suffered the most severe synaptic alterations, including a decrease in synaptic density and morphological alterations of the remaining synapses. Since Alzheimer’s disease cases show cortical atrophy, our data indicate a reduction in the total number (but not the density) of synapses at early stages of the disease, with this reduction being much more accentuated in subjects with late stages of Alzheimer’s disease. The observed synaptic alterations may represent a structural basis for the progressive learning and memory dysfunctions seen in Alzheimer’s disease cases.
Fishing rights and colonial government: institutional development in the Bengal Presidency
Authors: Sen Shourya , Adelstein Richard
Published: November 2020

We examine the evolution of fishing rights in colonial Bengal through a series of cases heard at the Calcutta High Court in the 1880s and culminating in the passage of legislation in 1889. We posit an implicit relational contract between the colonizing British and the landowning class in colonial Bengal as a way to understand the concurrent evolution of fishing rights and institutions of governance in the region. The system of incentives created by this contract determined the development of fishing rights at a crucial moment in the history of colonial Bengal and, more broadly, became a primary mechanism of institutional change in the region. The analysis also shows the High Court to have acted, albeit in vain, as a truly independent judiciary; had its resolution of the cases prevailed, the institutional development of the region might have been substantially different than it was.
Long-term outcomes and left ventricular diastolic function of sarcomere mutation-positive and mutation-negative patients with hypertrophic cardiomyopathy: a prospective cohort study
Authors: Chen Ching-Yu Julius , Su Mao-Yuan Marine , Liao Ying-Chieh , Chang Fu-Lan , Wu Cho-Kai , Lin Lian-Yu , Chen Yih-Shurng , Lin Yen-Hung , Hwang Juey-Jen , Yu Sung-Liang , Kao Hsien-Li , Chen Wen-Jone , Lu Tzu-Pin , Shih Ching-Yu , Yeh Shih-Fan Sherri , Yang Dun-Hui , Lai Ling-Ping , Juang Jyh-Ming Jimmy
Published: November 2020

Aims

Hypertrophic cardiomyopathy (HCM) is an inheritable disease that leads to sudden cardiac death and heart failure (HF). Sarcomere mutations (SMs) have been associated with HF. However, the differences in ventricular function between SM-positive and SM-negative HCM patients are poorly characterized.

Methods and results 

Of the prospectively enrolled 374 unrelated HCM patients in Taiwan, 115 patients underwent both 91 cardiomyopathy-related gene screening and cardiovascular magnetic resonance (45.6 ± 10.6 years old, 76.5% were male). Forty pathogenic/likely pathogenic mutations were identified in 52 patients by next-generation sequencing. The SM-positive group were younger at first cardiovascular event (P = 0.04) and progression to diastolic HF (P = 0.02) with higher N-terminal pro-brain natriuretic peptide (NT-proBNP) [New York Heart Association (NYHA) Class III/IV symptoms with left ventricular ejection fraction > 55%] than the SM-negative group (P < 0.001). SM-positive patients had a greater extent of late gadolinium enhancement (P = 0.01), larger left atrial diameter (P = 0.03), higher normalized peak filling rate (PFR) and PFR ratio, and a greater reduction in global longitudinal strain than SM-negative patients (all P ≤ 0.01). During mean lifelong follow-up time (49.2 ± 15.6 years), SM-positive was a predictor of earlier HF (NYHA Class III/IV symptoms) after multivariate adjustment (hazard ratio 3.5; 95% confidence interval 1.3–9.7; P = 0.015).

Conclusion

SM-positive HCM patients had a higher extent of myocardial fibrosis and more severe ventricular diastolic dysfunction than those without, which may contribute to earlier onset of advanced HF, suggesting the importance of close surveillance and early treatment throughout life.
Severe biventricular thrombosis in eosinophilic granulomatosis with polyangiitis: a case report
Authors: Hamudi Jihad , Karkabi Basheer , Zisman Devy , Shiran Avinoam
Published: November 2020

Background

Eosinophilic granulomatosis with polyangiitis (EGPA), formerly known as Churg–Strauss syndrome, is a rare multisystem disease characterized by asthma, rhinosinusitis, and eosinophilia. Cardiac involvement, present in half the patients, may be life threatening.

Case summary

A young woman with long-standing asthma and nasal polyposis was admitted with new-onset dyspnoea, sinus tachycardia, and eosinophilia. She had severe biventricular thrombosis and severe tricuspid regurgitation (TR) on echocardiography, with preserved ejection fraction of both ventricles. Cardiac magnetic resonance (CMR) imaging showed diffuse subendocardial late gadolinium enhancement (LGE). She had a positive test for perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) confirming the diagnosis of ANCA positive EGPA. She was treated with anticoagulation, high-dose corticosteroids, cyclophosphamide, and rituximab with gradual resolution of her symptoms. Follow-up echocardiography showed significant improvement in ventricular thrombi and TR but could not reliably exclude residual ventricular thrombus. Repeat CMR at 11 months confirmed complete resolution of both ventricular thrombi and near complete resolution of LGE.

Discussion

Cardiac involvement in EGPA, a rare cause of heart failure, can manifest as severe biventricular thrombosis and severe TR, resulting in heart failure with preserved ejection fraction. Combined immunosuppression and anticoagulation can lead to complete remission within a year. CMR is instrumental for both diagnosis and follow-up of EGPA, allowing for safe discontinuation of oral anticoagulation.
Who Will Do It? Volunteering to Change Cooperation Rules in a Heterogeneous Population
Authors: Gërxhani Klarita , Volker Beate , van Breemen Jacqueline
Published: November 2020

We study whether and when a second-order collective action problem, like the change of existing formal rules governing cooperation, can be resolved to ultimately solve first-order collective good dilemmas. We do so by examining the conditions under which individuals change cooperation rules when both their material incentives to cooperate and their social preferences for outcome distributions differ. Our experimental findings show that proselfs who benefit the most from cooperation are most likely to initiate a rule change to a higher minimum contribution level. Regarding prosocials, we find that their underlying motives in favour or against this rule change vary depending on their relative earnings’ position. If they are ‘wealthy’, that is, they have a higher earnings potential, they are more concerned about equality. When they are relatively ‘less wealthy’, they seem to care more about enhancing collective outcomes.
Coronavirus disease 2019 in adults with congenital heart disease: a position paper from the ESC working group of adult congenital heart disease, and the International Society for Adult Congenital Heart Disease
Authors: Diller Gerhard-Paul , Gatzoulis Michael A , Broberg Craig S , Aboulhosn Jamil , Brida Margarita , Schwerzmann Markus , Chessa Massimo , Kovacs Adrienne H , Roos-Hesselink Jolien
Published: November 2020

We are witnessing an unparalleled pandemic caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) associated with coronavirus disease 2019 (COVID-19). Current data show that SARS-CoV-2 results in mild flu-like symptoms in the majority of healthy and young patients affected. Nevertheless, the severity of COVID-19 respiratory syndrome and the risk of adverse or catastrophic outcomes are increased in patients with pre-existing cardiovascular disease. Patients with adult congenital heart disease (ACHD)—by definition—have underlying cardiovascular disease. Many patients with ACHD are also afflicted with residual haemodynamic lesions such as valve dysfunction, diminished ventricular function, arrhythmias or cyanosis, have extracardiac comorbidities, and face additional challenges regarding pregnancy. Currently, there are emerging data of the effect of COVID-19 on ACHD patients, but many aspects, especially risk stratification and treatment considerations, remain unclear. In this article, we aim to discuss the broad impact of COVID-19 on ACHD patients, focusing specifically on pathophysiology, risk stratification for work, self-isolation, hospitalization, impact on pregnancy, psychosocial health, and longer-term implications for the provision of ACHD care.
Divergence in environmental adaptation between terrestrial clades of the Bacillus cereus group
Authors: Manktelow C James , White Hugh , Crickmore Neil , Raymond Ben
Published: November 2020

The Bacillus cereus group encompasses beneficial and harmful species in diverse niches and has a much debated taxonomy. Investigating whether selection has led to ecological divergence between phylogenetic clades can help understand the basis of speciation, and has implications for predicting biological safety across this group. Using three most terrestrial species in this group (B. cereus, Bacillus thuringiensis and Bacillus mycoides) we charactererized ecological specialization in terms of resource use, thermal adaptation and fitness in different environmental conditions and tested whether taxonomic species or phylogenetic clade best explained phenotypic variation. All isolates grew vigorously in protein rich media and insect cadavers, but exploitation of soil or plant derived nutrients was similarly weak for all. For B. thuringiensis and B. mycoides, clade and taxonomic species were important predictors of relative fitness in insect infections. Fully psychrotolerant isolates could outcompete B. thuringiensis in insects at low temperature, although psychrotolerance predicted growth in artificial media better than clade. In contrast to predictions, isolates in the Bacillus anthracis clade had sub-optimal growth at 37°C. The common ecological niche in these terrestrial B. cereus species is the ability to exploit protein rich resources such as cadavers. However, selection has led to different phylogenetic groups developing different strategies for accessing this resource. Thus, clades, as well as traditional taxonomic phenotypes, predict biologically important traits.