bluuebunny/crossref_metadata_2025 huggingface dataset:
Suprathermal electron moments in the ionosphere
Authors: Marif Hanane , Lilensten Jean
Published: May 2020

The ionospheric electron population is divided into two groups. The ambient electrons are thermalized. Their energy is usually smaller than one electron volt. Their densities and temperatures are the usual ones measured by incoherent scatter radars, or modeled by international codes such as International Reference Ionosphere (IRI). There is however a second population called the suprathermal electrons. This one is either due to photoionization or to electron impact between the thermosphere and the precipitation in the high latitude zone. In the frame of space weather, it may be the source of scintillations, plasma bulks and other physical phenomena. The suprathermal electron population can only indirectly be measured through the plasmaline and had never been modeled. Its modeling requires the computation of the electron stationary flux by solving the Boltzmann transport equation. This flux is multiplied by various powers of the velocity v and integrated to obtain the different order moments. By integrating f over v0dv, one deduces the suprathermal electron density. An integration of v1fdv allows the computation of their mean velocity. Higher moments give access to their temperature and finally to their heat flux. In this work, we demonstrate for the first time the full and rigorous calculation of the ionospheric electron moments up to three. As two case studies, we focus on high latitude in the auroral oval and low magnetic latitude over Algiers for different solar and geophysical conditions. We compare the suprathermal densities and temperatures to the thermal electron parameters. Our results highlight that – as expected – the suprathermal density is small compared to the thermal one. Although it is close to 3 × 103 m−3 at 180 km during the day, it drops drastically at night, to hardly reach 3 m−3. Contrarily to the density, the velocity is about 10 times more important during the nighttime when precipitation occurs than during the daytime under the electromagnetic solar flux. At 400 km, it varies during the day between 700,000 m s−1 (active solar conditions) and 900,000 m s−1 (quiet Sun). At night, the velocity varies between 3 × 106 m s−1 (low mean energy precipitation) and 3 × 107 m s−1 (high mean energy precipitation) at 400 km. The suprathermal temperature increases as the solar activity decreases or as the mean energy of the electron precipitation increases. It may reach values close to 3 × 108 K. The heat flux may be fully oriented downward or experiences a reversal with some flux going up depending on the forcing.
Prävalenz und Relevanz der
Medikamentenabhängigkeit
Authors: Wodarz Norbert
Published: May 2020

Dr. Gallus Bischof und PD Dr. Friedrich Wurst im Gespräch mit Prof. Dr.
Norbert Wodarz, Chefarzt des Zentrums für Suchtmedizin, sowie
stellvertretender Ärztlicher Direktor der Klinik und Poliklinik für
Psychiatrie und Psychotherapie der Universität Regensburg am Bezirksklinikum
medbo.
Synovial Fluid Mesenchymal Stem Cells for Knee Arthritis and Cartilage Defects: A Review of the Literature
Authors: Fang William , Sun ZhiTao , Chen Xiao , Han Bo , Vangsness C. Thomas
Published: May 2020

Mesenchymal stem cells (MSCs) are adult stem cells that have the ability to self-renew and differentiate into several cell lineages including adipocytes, chondrocytes, tenocytes, bones, and myoblasts. These properties make the cell a promising candidate for regenerative medicine applications, especially when dealing with sports injuries in the knee. MSCs can be isolated from almost every type of adult tissue. However, most of the current research focuses on MSCs derived from bone marrow, adipose, and placenta derived products. Synovial fluid-derived MSCs (SF-MSCs) are relatively overlooked but have demonstrated promising therapeutic properties including possessing higher chondrogenic proliferation capabilities than other types of MSCs. Interestingly, SF-MSC population has shown to increase exponentially in patients with joint injury or disease, pointing to a potential use as a biomarker or as a treatment of some orthopaedic disorders. In this review, we go over the current literature on synovial fluid-derived MSCs including the characterization, the animal studies, and discuss future perspectives.
Vertical Transmission of Severe Acute Respiratory Syndrome Coronavirus 2: A Systematic Review
Authors: Yang Ziyi , Liu Yi
Published: May 2020

Objective The aim of this study is to summarize currently available evidence on vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Study Design A systematic review was conducted following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analysis Statement.

Results A total of 22 studies comprising 83 neonates born to mothers diagnosed with coronavirus disease 2019 were included in the present systematic review. Among these neonates, three were confirmed with SARS-CoV-2 infection at 16, 36, and 72 hours after birth, respectively, by nasopharyngeal swab real-time polymerase chain reaction (RT-PCR) tests; another six had elevated virus-specific antibody levels in serum samples collected after birth, but negative RT-PCR test results. However, without positive RT-PCR tests of amniotic fluid, placenta, or cord blood, there is a lack of virologic evidence for intrauterine vertical transmission.

Conclusion There is currently no direct evidence to support intrauterine vertical transmission of SARS-CoV-2. Additional RT-PCR tests on amniotic fluid, placenta, and cord blood are needed to ascertain the possibility of intrauterine vertical transmission. For pregnant women infected during their first and second trimesters, further studies focusing on long-term outcomes are needed.

Key Points
On the conicity of eigenvalues intersections for parameter-dependent self-adjoint operators
Authors: Chittaro Francesca Carlotta , Mason Paolo
Published: May 2020

Motivated by recent controllability results for the bilinear Schrödinger equation based on the existence of conical intersections, in this paper we identify two physically interesting families of parameter-dependent Hamiltonians that admit residual and prevalent subfamilies for which all double eigenvalues are conical. In order to obtain such a result, we exploit a characterization of conical intersections in terms of a transversality condition which allows us to apply a suitable transversality theorem.
Cp2Mg-induced transition metal ion contamination and performance loss in MOCVD-grown blue emitting InGaN/GaN multiple quantum wells
Authors: Liu Richard , Tucker Eric , Lee Soo Min , Kasarla Kalyan , McCormick Callan , Bayram Can
Published: May 2020

The detrimental effects of Cp2Mg-induced trace transition metal (iron and manganese) contamination on the optical performance of metalorganic chemical vapor deposition (MOCVD)-grown blue-emitting InGaN/GaN multiple quantum wells (MQWs) are investigated experimentally. Five samples are grown at various stages of conditioning of a freshly installed MOCVD tool with stainless steel gas lines. Without conditioning, Cp2Mg flow induced Fe and Mn impurities with concentrations of 3×1015 and 3×1014 cm−3, respectively. These contaminants introduce nonradiative recombination centers with lifetimes on the order of nanoseconds. These impurities also induce indium-clustering related phenomena such as low energy shoulder at low temperature and a strong S-curve shift in emission energy with increasing temperature. Through successive cycles of chamber conditioning, the Fe and Mn concentrations decrease to below their detection limits, and the nonradiative recombination lifetime (+8 ns), internal quantum efficiency (+26%), microphotoluminescence nonuniformity (−4.7%), and S-curve shift (−26 meV) of the MQWs improved. The suppression of the transition metal ion contamination in the MOCVD chamber is shown to be crucial for high performance MQWs and blue light emitting diode growths.
Three terminal nano-oscillator based on domain wall pinning by track defect and anisotropy control
Authors: Toro Oscar O. , Alves Sidiney G. , Carvalho-Santos Vagson L. , de Araújo Clodoaldo I. L.
Published: May 2020

The proper understanding of the dynamical properties of magnetization collective modes is a cornerstone for future applications in spintronic devices based on the domain wall (DW) motion. In this work, through micromagnetic simulations and analytical calculations, we study the rotation of a DW pinned by a T-shaped defect on an anisotropic magnetic nanostripe. We show that the competition between the torques produced by the magnetostatic field generated by the T-shaped defect and the applied electric current makes the DW stop at a specific position along the track, and start to turn around the in-plane direction with a specific rotation frequency depending on anisotropy and current density. It is also shown that the distance between the DW position and the T-shaped structure position depends on the anisotropy constant of the nanostripe. Finally, it is proposed as an experimental setting considering that the DW rotation mode can be used to induce the rotation of magnetization of a magnetic nanodisc by a magnetic tunnel junction device. We have then shown that this experimental arrangement can be considered as a three-terminal nano-oscillator.
Host–virus evolutionary dynamics with specialist and generalist infection strategies: Bifurcations, bistability, and chaos
Authors: Nurtay Anel , Hennessy Matthew G. , Alsedà Lluís , Elena Santiago F. , Sardanyés Josep
Published: May 2020

In this work, we have investigated the evolutionary dynamics of a generalist pathogen, e.g., a virus population, that evolves toward specialization in an environment with multiple host types. We have particularly explored under which conditions generalist viral strains may rise in frequency and coexist with specialist strains or even dominate the population. By means of a nonlinear mathematical model and bifurcation analysis, we have determined the theoretical conditions for stability of nine identified equilibria and provided biological interpretation in terms of the infection rates for the viral specialist and generalist strains. By means of a stability diagram, we identified stable fixed points and stable periodic orbits, as well as regions of bistability. For arbitrary biologically feasible initial population sizes, the probability of evolving toward stable solutions is obtained for each point of the analyzed parameter space. This probability map shows combinations of infection rates of the generalist and specialist strains that might lead to equal chances for each type becoming the dominant strategy. Furthermore, we have identified infection rates for which the model predicts the onset of chaotic dynamics. Several degenerate Bogdanov–Takens and zero-Hopf bifurcations are detected along with generalized Hopf and zero-Hopf bifurcations. This manuscript provides additional insights into the dynamical complexity of host–pathogen evolution toward different infection strategies.
SABRE polarized low field rare-spin spectroscopy
Authors: Lehmkuhl Sören , Suefke Martin , Kentner Arne , Yen Yi-Fen , Blümich Bernhard , Rosen Matthew S. , Appelt Stephan , Theis Thomas
Published: May 2020

High-field nuclear magnetic resonance (NMR) spectroscopy is an indispensable technique for identification and characterization of chemicals and biomolecular structures. In the vast majority of NMR experiments, nuclear spin polarization arises from thermalization in multi-Tesla magnetic fields produced by superconducting magnets. In contrast, NMR instruments operating at low magnetic fields are emerging as a compact, inexpensive, and highly accessible alternative but suffer from low thermal polarization at a low field strength and consequently a low signal. However, certain hyperpolarization techniques create high polarization levels on target molecules independent of magnetic fields, giving low-field NMR a significant sensitivity boost. In this study, SABRE (Signal Amplification By Reversible Exchange) was combined with high homogeneity electromagnets operating at mT fields, enabling high resolution 1H, 13C, 15N, and 19F spectra to be detected with a single scan at magnetic fields between 1 mT and 10 mT. Chemical specificity is attained at mT magnetic fields with complex, highly resolved spectra. Most spectra are in the strong coupling regime where J-couplings are on the order of chemical shift differences. The spectra and the hyperpolarization spin dynamics are simulated with SPINACH. The simulations start from the parahydrogen singlet in the bound complex and include both chemical exchange and spin evolution at these mT fields. The simulations qualitatively match the experimental spectra and are used to identify the spin order terms formed during mT SABRE. The combination of low field NMR instruments with SABRE polarization results in sensitive measurements, even for rare spins with low gyromagnetic ratios at low magnetic fields.
CR-39 nuclear track detector response to inertial confinement fusion relevant ions
Authors: Lahmann B. , Gatu Johnson M. , Frenje J. A. , Glebov Y. Yu. , Rinderknecht H. G. , Séguin F. H. , Sutcliffe G. , Petrasso R. D.
Published: May 2020

The detection properties of CR-39 were investigated for protons, deuterons, and tritons of various energies. Two models for the relationship between the track diameter and particle energy are presented and demonstrated to match experimental data for all three species. Data demonstrate that CR-39 has 100% efficiency for protons between 1 MeV and 4 MeV, deuterons between 1 MeV and 12.2 MeV, and tritons between 1 MeV and 10 MeV. The true upper bounds for deuterons and tritons exceed what could be measured in data. Simulations were developed to further explore the properties of CR-39 and suggest that the diameter–energy relationship of alpha particles cannot be captured by the conventional c-parameter model. These findings provide confidence in CR-39 track diameter based spectroscopy of all three species and provide invaluable insight for designing filtering for all CR-39 based diagnostics.
Direct observation of muonium reacting with uncapped gold nanoparticles in porous silica and nature of the final state
Authors: Dehn M. H. , Cao Y. , Wang P.-X. , Cottrell S. P. , MacLachlan M. J. , Fleming D. G. , Kiefl R. F.
Published: May 2020

We report the reaction of muonium (Mu = [μ+e−]), a light isotopic analog of hydrogen, with uncapped gold nanoparticles embedded in mesoporous silica. Using the radio-frequency muon spin rotation (RF-μSR) technique, we directly observe and characterize the resulting final state on the nanoparticle surface, showing conclusively its diamagnetic nature. The magnetic environment experienced by the reacted muons is only weakly perturbed compared to that of muons in a silica reference, consistent with the surface of the gold nanoparticles being metallic and non-magnetic. We demonstrate the potential of RF-μSR for the investigation of the surface properties of nanoparticles and show the feasibility of Knight shift measurements of muons on metal surfaces.
Near-field mapping of the edge mode of a topological valley slab waveguide at λ = 1.55
μ
m
Authors: Dubrovkin Alexander M. , Chattopadhyay Udvas , Qiang Bo , Buchnev Oleksandr , Wang Qi Jie , Chong Yidong , Zheludev Nikolay I.
Published: May 2020

Valley-polarized topological states of light allow for robust waveguiding, which has been demonstrated for transverse-electric modes in THz and near-infrared regions of the spectrum. As the topological protection relies on guiding the light via a highly structured surface, direct imaging of the photonic modes at subunit cell resolution is of high interest but challenging, particularly for transverse-magnetic modes. Here, we report mapping the transverse-magnetic modes in a valley photonic crystal waveguide using scattering-type scanning near-field optical microscopy at the optical telecom C-band wavelength. The waveguide based on a triangular air-hole motif with broken inversion symmetry is fabricated from the suspended germanium layer. We observed the launching and guiding of the transverse-magnetic edge mode along the boundary between topologically distinct domains with opposite valley Chern indices. These results are supported by theoretical simulations and provide insight into the design and use of topological protected states for applications in densely integrated optical telecommunication devices.
TURBOMOLE: Modular program suite for ab initio quantum-chemical and condensed-matter simulations
Authors: Balasubramani Sree Ganesh , Chen Guo P. , Coriani Sonia , Diedenhofen Michael , Frank Marius S. , Franzke Yannick J. , Furche Filipp , Grotjahn Robin , Harding Michael E. , Hättig Christof , Hellweg Arnim , Helmich-Paris Benjamin , Holzer Christof , Huniar Uwe , Kaupp Martin , Marefat Khah Alireza , Karbalaei Khani Sarah , Müller Thomas , Mack Fabian , Nguyen Brian D. , Parker Shane M. , Perlt Eva , Rappoport Dmitrij , Reiter Kevin , Roy Saswata , Rückert Matthias , Schmitz Gunnar , Sierka Marek , Tapavicza Enrico , Tew David P. , van Wüllen Christoph , Voora Vamsee K. , Weigend Florian , Wodyński Artur , Yu Jason M.
Published: May 2020

TURBOMOLE is a collaborative, multi-national software development project aiming to provide highly efficient and stable computational tools for quantum chemical simulations of molecules, clusters, periodic systems, and solutions. The TURBOMOLE software suite is optimized for widely available, inexpensive, and resource-efficient hardware such as multi-core workstations and small computer clusters. TURBOMOLE specializes in electronic structure methods with outstanding accuracy–cost ratio, such as density functional theory including local hybrids and the random phase approximation (RPA), GW-Bethe–Salpeter methods, second-order Møller–Plesset theory, and explicitly correlated coupled-cluster methods. TURBOMOLE is based on Gaussian basis sets and has been pivotal for the development of many fast and low-scaling algorithms in the past three decades, such as integral-direct methods, fast multipole methods, the resolution-of-the-identity approximation, imaginary frequency integration, Laplace transform, and pair natural orbital methods. This review focuses on recent additions to TURBOMOLE’s functionality, including excited-state methods, RPA and Green’s function methods, relativistic approaches, high-order molecular properties, solvation effects, and periodic systems. A variety of illustrative applications along with accuracy and timing data are discussed. Moreover, available interfaces to users as well as other software are summarized. TURBOMOLE’s current licensing, distribution, and support model are discussed, and an overview of TURBOMOLE’s development workflow is provided. Challenges such as communication and outreach, software infrastructure, and funding are highlighted.
Linear dependence of skyrmion velocity on response resonance frequency of local magnetization
Authors: Kong Lingwen , Bo Lan , Zhao Rongzhi , Hu Chenglong , Ji Lianze , Zhang Yanhui , Zhang Xuefeng
Published: May 2020

Spin waves (SWs) have been proven effective in driving the magnetic skyrmion motion, while the physical correlation between skyrmion velocity and the resonance frequency of local magnetization remains unknown. Here, we theoretically investigate the skyrmion motion in a magnetic Co/Pt nanotrack with the perpendicular magnetic anisotropy, which is driven by SWs. The results show that magnetic skyrmions move along the propagation direction of SWs in a specific frequency range (50–175 GHz). It is evidenced that there is a linear relationship between the response resonance frequency (fr) of local magnetization and the skyrmion velocity (v), and the motion of skyrmions could also be manipulated by controlling the amplitude and location of the exciting source. The present study provides a fundamental insight into understanding the intrinsic physics of SW-driven skyrmion-based devices.
Realizing single-mode lasing of cadmium selenide nanoribbons with strain engineering
Authors: Yu Zhaopeng , Sun Liaoxin , Lu Yue , Sun Yan , Zhang Bo , Xu Jingcheng , Shen Xuechu , Lu Wei
Published: May 2020

Semiconductor nanowires/nanoribbons have great potential in nanoscale lasers because of their intrinsic laser capabilities and excellent optoelectronic properties. However, these as-grown nanostructures, lacking precise structural controllability, usually show multimode lasing, which hinders their applications in on-chip functional optoelectronic devices. In this work, by using a home-made strain apparatus, we obtained out-of-plane buckled cadmium selenide nanoribbons, resulting in a single-mode lasing at the curved part of the nanoribbons. Taking into consideration the bending structure of nanoribbons, we speculate that deformation-induced light confinement and strain-driven carrier's redistribution contributed mainly to the single-mode lasing. Moreover, a periodic out-of-plane bending of nanoribbons is realized by thermal controlling deformation of the elastic substrate and cadmium selenide, in which single-mode lasing at each crest part can be obtained. Our work opened an alternative avenue to realize nanoscale single-mode lasers, which was quite useful for flexible optoelectronic devices.
The aerodynamic performance of passive wing pitch in hovering flight
Authors: Lei Menglong , Li Chengyu
Published: May 2020

Insect wings can passively maintain a high angle of attack during each flapping stroke without the aid of the active pitching motion due to the torsional flexibility of the wing basal region. However, there is no clear understanding of how torsional wing flexibility should be designed for achieving optimal aerodynamic performance. In this work, a computational study was conducted to investigate the passive pitching mechanism of a fruit fly wing in hovering flight using a torsional spring model. The torsional wing stiffness was characterized by the Cauchy number, a ratio between the aerodynamic force and the structural elastic force. Different flapping patterns including zero-deviation, figure-8, and oval-shaped flapping trajectories were evaluated along a horizontal stroke plane. The aerodynamic forces and associated unsteady flow structures were simulated using an in-house immersed-boundary-method based computational fluid dynamics solver. A parametric study on the Cauchy number was performed with a Reynolds number of 300. According to the analysis of the aerodynamic performance, we found that a balance of high lift and high lift-to-power ratio can be achieved in a particular range of Cauchy numbers (0.15–0.30) for all different flapping trajectories. This range is consistent with the Cauchy number calculated based on the experimental measurements of a fruit fly in the literature. In addition, 3D wake structures generated by the passive flapping wings were analyzed in detail. The findings of this work could provide important implications for designing more efficient flapping-wing micro-air vehicles.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: May 2020

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials which supersede earlier data or suggest new research applications.
Coastal Plants
Authors: Dixon Kingsley
Published: May 2020

The greater Perth coast is a biodiverse and ecologically vulnerable region, with its unique native plant species threatened by clearing, invasive species, fire and climate change. This second edition of Coastal Plants has been updated and expanded to provide a definitive guide to 128 of the most common plants of the Perth coastal region. It includes the key species used in coastal restoration, along with important weeds. The description of each species is accompanied by a distribution map and diagnostic photographs of the whole plant, flowers, seeds and fruits. The book also contains introductory chapters on the biology and ecology of the coastal plants, their biogeography, and practical approaches to the restoration of coastal dune vegetation.
Coastal Plants is distinctive in its focus on restoration, which makes it valuable for community groups and individuals interested or involved in coastal natural history or restoration activities.
Sources and dynamics of international funding for waterfowl conservation in the Prairie Pothole Region of North America
Authors: Mattsson B. J. , Devries J. H. , Dubovsky J. A. , Semmens D. , Thogmartin W. E. , Derbridge J. J. , Lopez-Hoffman L.
Published: May 2020

Abstract ContextFunding for habitat-management programs to maintain population viability is critical for conservation of migratory species; however, such financial resources are limited and can vary greatly over time. The Prairie Pothole Region (PPR) of North America is an excellent system for examining spatiotemporal patterns of funding for waterfowl conservation, because this transboundary region is crucial for reproduction and migration of many duck species. AimsWe examine large-scale spatiotemporal variation in funding for waterfowl habitat conservation in the PPR during 2007–2016. Specifically, we quantify major sources of funding and how funds were directed towards particular geographies within Canada and the USA. We further examine how sources and magnitude of funding changed over time and in relation to numbers of hunters. MethodsWe assembled data from multiple sources to quantify funding (in US$, 2016 values) from (1) USA states and non-government organisations (NGOs), (2) Canadian government and NGOs, and (3) major USA-based federal funding sources to the Canadian and US portions of the PPR between 2007 and 2016. We fit linear regressions to examine spatiotemporal variation in funding and in numbers of active waterfowl hunters in the USA. Key resultsWhereas annual funding for the Canadian portion was comparatively stable throughout the 10 years (range: US$25–41 million), funding for the US portion was dynamic and increased between the first (range: US$36–48 million) and second (range: US$43–117 million) 5-year intervals, despite concurrent declines in the number of active waterfowl hunters in the USA. ConclusionsWe discovered contrasting trends and dynamics in multiple streams of funding for habitat conservation on each side of the border bisecting the PPR. These findings and approaches warrant closer attention by wildlife professionals. Work is needed to analyse past and future funding for habitat conservation, which can then be used to refine plans for maintaining or recovering populations of migratory species. ImplicationsAlthough funding for waterfowl habitat conservation in the PPR increased over the past decade, trends were inconsistent among subregions and uncertain for some major funding sources. Better understanding of the complexities in funding will help inform more efficient long-term planning efforts for conservation of waterfowl and other migratory species.
Paradoxical population resilience of a keystone predator to a toxic invasive species
Authors: Doody J. Sean , Rhind David , Clulow Simon
Published: May 2020

Abstract
ContextThe invasive cane toad (Rhinella marina) has decimated populations of a keystone predator, the yellow-spotted monitor (Varanus panoptes), causing trophic cascades in Australian animal communities. Paradoxically, some V. panoptes populations coexist with toads. Demonstrating patterns in heterogeneous population-level impacts could reveal mechanisms that mediate individual effects, and provide managers with the ability to predict future impacts and assist in population recovery.
AimsThe aim of the present study was to search for spatial patterns of population resilience of V. panoptes to invasive cane toads.
MethodsPublished literature, unpublished data, reports and anecdotal information from trained herpetologists were used to test the emerging hypothesis that resilient predator populations are mainly coastal, whereas non-resilient populations are mostly inland.
Key resultsPost-toad invasion data from 23 V. panoptes populations supported the idea that toad impacts on V. panoptes were heterogeneous; roughly half the populations could be designated as resilient (n=13) and half as non-resilient (n=10). Resilient populations had longer times since toad invasion than did non-resilient populations (39 versus 9 years respectively), supporting the idea that some recovery can occur. Non-resilient populations were exclusively inland (n=10), whereas resilient populations were split between inland (n=5) and coastal (n=8) populations. Resilient inland populations, however, were mainly confined to areas in which decades had passed since toad invasion.
ConclusionsThe findings suggest that coastal V. panoptes populations fare much better than inland populations when it comes to surviving invading cane toads.
ImplicationsUnambiguous recovery of monitor populations remains undemonstrated and will require long-term population monitoring before and after toad invasion.
Effect of strains on textural evolution of hydrostatically extruded niobium tubes
Authors: Lee Jongbeom , Park SangYong , Jeong Haguk
Published: May 2020

The influence of tube strains on tube deformation ratios and textural evolution during the deformation of pure Nb tubes subjected to hydrostatic extrusion was investigated. The tube deformation ratios increased with increasing tube strains. A very strong <111> fibre texture at a lower strain transformed to a dual strong <100> and weak <111> fibre texture at a higher strain. The texture evolution led to an increase in the Taylor factor at the drawing tensor.
Identity from a conceptual and empirical perspective: a case study of the multiply identifications of Slovak diaspora living in Serbia
Authors: Surova Svetluša
Published: May 2020

The current challenges stemming from migration, globalism, and the highly interconnected world, underline the importance of identities, not only for individuals but for social and political life too. For the past few decades, identity has become a significant concept in social sciences and an important political issue in many contemporary societies. Today collective identities seem to form a central concept in both theoretical and empirical studies of social movements, political mobilization and democratic legitimacy. This paper examines identity in multilevel contexts, from both conceptual and empirical perspectives. The paper seeks to critically analyse how the term ‘identity’ is used, defined and conceptualized in the social sciences, the national laws of Slovakia and Serbia; how it is built and constructed in Slovakia and how it is performed on the ground in diaspora. A mixed research design was applied, combining qualitative and quantitative approaches. The study concludes that scholars today agree on what identity is in the social sciences, however academic, state and ordinary usages and understandings of the concept of identity vary in different contexts. Further, the study argues that Slovak national identity and other collective identities, together with Slovak-ness, are perceived in different ways at a state level and among ordinary people in the Slovak diaspora. Studying identity construction and identity performance on different levels, such as the state level and on the ground, both at home and in diaspora, can contribute to our understanding of the complexity of the identity concept and identification processes.
Trees and forests in nuclear physics
Authors: Carnini M , Pastore A
Published: May 2020

We present a simple introduction to the decision tree algorithm using some examples from nuclear physics. We show how to improve the accuracy of the classical liquid drop nuclear mass model by performing feature engineering with a decision tree. Finally, we apply the method to the Duflo–Zuker model showing that, despite their simplicity, decision trees are capable of improving the description of nuclear masses using a limited number of free parameters.
His/Met heme ligation in the PioA outer membrane cytochrome enabling light-driven extracellular electron transfer by Rhodopseudomonas palustris TIE-1
Authors: Li Dao-Bo , Edwards Marcus J , Blake Anthony W , Newton-Payne Simone E , Piper Samuel E H , Jenner Leon P , Sokol Katarzyna P , Reisner Erwin , Van Wonderen Jessica H , Clarke Thomas A , Butt Julea N
Published: May 2020

A growing number of bacterial species are known to move electrons across their cell envelopes. Naturally this occurs in support of energy conservation and carbon-fixation. For biotechnology it allows electron exchange between bacteria and electrodes in microbial fuel cells and during microbial electrosynthesis. In this context Rhodopseudomonas palustris TIE-1 is of much interest. These bacteria respond to light by taking electrons from their external environment, including electrodes, to drive CO2-fixation. The PioA cytochrome, that spans the bacterial outer membrane, is essential for this electron transfer and yet little is known about its structure and electron transfer properties. Here we reveal the ten c-type hemes of PioA are redox active across the window +250 to −400 mV versus Standard Hydrogen Electrode and that the hemes with most positive reduction potentials have His/Met and His/H2O ligation. These chemical and redox properties distinguish PioA from the more widely studied family of MtrA outer membrane decaheme cytochromes with ten His/His ligated hemes. We predict a structure for PioA in which the hemes form a chain spanning the longest dimension of the protein, from Heme 1 to Heme 10. Hemes 2, 3 and 7 are identified as those most likely to have His/Met and/or His/H2O ligation. Sequence analysis suggests His/Met ligation of Heme 2 and/or 7 is a defining feature of decaheme PioA homologs from over 30 different bacterial genera. His/Met ligation of Heme 3 appears to be less common and primarily associated with PioA homologs from purple non-sulphur bacteria belonging to the alphaproteobacteria class.
A simple method to prepare superhydrophobic and regenerable antibacterial films
Authors: Liang Xiaomei , Chen Xin , Zhu Jianli , Liu Lixian , Wang Wei , Wang Xu , Qu Chunsheng
Published: May 2020

Macromolecules incorporating N-halamines have shown significant antibacterial properties and can be regenerated by chlorination. In this work, a new type of regenerable material made of nano-sized latex particles having N-H groups was prepared via the emulsion polymerization of methacrylamide and dodecafluoroheptyl methacrylate with divinylbenzene as a crosslinker. The N-H moieties in this polymer were subsequently transformed into N-Cl groups by chlorination with an aqueous sodium hypochlorite solution, and films were prepared by casting on substrates previously coated with a self-adhesive silicone rubber. The nanoparticles and the films were characterized by Fourier transform infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), contact angle measurements, scanning electron microscopy (SEM) and microbiological tests. The results showed that F and Cl were successfully incorporated in the nanoparticles, that the films were thermally stable and hydrophobic (with a contact angle of 152°), and that these materials exhibited antimicrobial properties. The N-Cl groups killed bacteria by releasing active chlorine as they transitioned to N-H groups, and could be re-chlorinated with a methanol solution of isocyanuric chloride. FTIR and XPS analyses confirmed this regeneration, while SEM image showed that the morphology of the original microspheres was maintained after re-chlorination. The re-chlorinated films also maintained superhydrophobic and bactericidal characteristics.
Operative and Technical Modifications to the Coriolis® µ Air Sampler That Improve Sample Recovery and Biosafety During Microbiological Air Sampling
Authors: Rufino de Sousa Nuno , Shen Lei , Silcott David , Call Charles J , Rothfuchs Antonio Gigliotti
Published: May 2020

Detecting infectious aerosols is central for gauging and countering airborne threats. In this regard, the Coriolis® µ cyclonic air sampler is a practical, commercial collector that can be used with various analysis methods to monitor pathogens in air. However, information on how to operate this unit under optimal sampling and biosafety conditions is limited. We investigated Coriolis performance in aerosol dispersal experiments with polystyrene microspheres and Bacillus globigii spores. We report inconsistent sample recovery from the collector cone due to loss of material when sampling continuously for more than 30 min. Introducing a new collector cone every 10 min improved this shortcoming. Moreover, we found that several surfaces on the device become contaminated during sampling. Adapting a high efficiency particulate air-filter system to the Coriolis prevented contamination without altering collection efficiency or tactical deployment. A Coriolis modified with these operative and technical improvements was used to collect aerosols carrying microspheres released inside a Biosafety Level-3 laboratory during simulations of microbiological spills and aerosol dispersals. In summary, we provide operative and technical solutions to the Coriolis that optimize microbiological air sampling and improve biosafety.
Climbing rice plants above the waterline: escape of freshwater snails from underwater predation by snail-eating specialists
Authors: Hayashi Masakazu , Sugiura Shinji
Published: May 2020

Freshwater molluscs have physical defences such as shells to protect their inner soft bodies from underwater predators. However, some predators have specialized mouthparts that can destroy the snail’s tough and/or spiral shells. Therefore, these snails could have evolved specific defences against their specialist predators. We observed the freshwater snail Austropeplea ollula (Pulmonata: Lymnaeidae) frequently climbing rice plants above the water in paddy fields in Shimane, central Japan. We also found the beetle larvae of Hydrophilus acuminatus (Coleoptera: Hydrophilidae), which are known as snail-eating specialists, in waters of the same paddy fields. We hypothesized that A. ollula climbs rice plants above the water to escape underwater predation by H. acuminatus and that the escape behaviour of snails may be specifically triggered by chemical cues from snail-eating specialists and/or killed conspecifics. To test both these hypotheses, we conducted laboratory experiments. The results demonstrated that chemical cues (e.g. body fluids) from killed conspecifics could trigger A. ollula to crawl above the waterline. Furthermore, chemical cues (e.g. scent and digestive enzymes) from H. acuminatus could promote the behaviour. Therefore, A. ollula can successfully escape from H. acuminatus by climbing the rice plants above the water.
Non-local network dynamics via fractional graph Laplacians
Authors: Benzi Michele , Bertaccini Daniele , Durastante Fabio , Simunec Igor
Published: May 2020

We introduce non-local dynamics on directed networks through the construction of a fractional version of a non-symmetric Laplacian for weighted directed graphs. Furthermore, we provide an analytic treatment of fractional dynamics for both directed and undirected graphs, showing the possibility of exploring the network employing random walks with jumps of arbitrary length. We also provide some examples of the applicability of the proposed dynamics, including consensus over multi-agent systems described by directed networks.
Prediction of lymph node metastasis in superficial esophageal squamous cell carcinoma in Asia: a systematic review and meta-analysis
Authors: Xu Wen , Liu Xiao-bo , Li Sheng-bao , Yang Zhi-hao , Tong Qiang
Published: May 2020

A less invasive endoscopic therapy has been used as a routine treatment for superficial esophageal squamous cell carcinoma (SESCC). However, lymph node metastasis (LNM) in SESCC limits the effectiveness of this medical procedure. This meta-analysis aimed to screen the risk factors for LNM in SESCC in Asia to provide evidence for clinicians in selecting treatment. We searched the main reference databases for research involving patients who received esophagectomy (open or minimally invasive) with lymph node dissection for SESCC. Meta-analysis was performed using RevMan 5.3 software. Twenty studies including 3983 patients were obtained in this analysis. The meta-analysis showed that tumor size, macroscopic type of tumor, degree of differentiation, depth of tumor invasion, and lymphovascular involvement are risk factors of LNM in SESCC, whereas age, sex, and tumor location showed no association with LNM. Five variables were screened as predictive factors for LNM in SESCC. The incidence of LNM in SESCC is not rare, and the physicians must be careful when making clinical decisions.
Robotic transhiatal esophagectomy
Authors: Broderick Ryan C , Horgan Santiago , Fuchs Hans F
Published: May 2020

Horgan et al. described the first robotic-assisted transhiatal esophagectomy in 2003. Although there is debate regarding the oncologic appropriateness of transhiatal versus thoracic approach to esophagectomy in malignancy, comparative data are still lacking. This paper with video describes step by step how and when to perform a transhiatal robotic-assisted resection in patients with esophageal cancer.
Sex-specific difference in the association between arterial stiffness and subclinical left ventricular dysfunction
Authors: Yoshida Yuriko , Nakanishi Koki , Daimon Masao , Ishiwata Jumpei , Sawada Naoko , Hirokawa Megumi , Kaneko Hidehiro , Nakao Tomoko , Mizuno Yoshiko , Morita Hiroyuki , Di Tullio Marco R , Homma Shunichi , Komuro Issei
Published: May 2020

Aims 

Increased arterial stiffness is one of the key mechanisms of heart failure with preserved ejection fraction (HFpEF). However, the possible association between arterial stiffness and subclinical left ventricular (LV) dysfunction and its sex-specific difference remains unclarified. LV strain is emerging as a highly sensitive tool to unmask early LV abnormalities.

Methods and results 

We examined 1155 participants free of overt cardiovascular disease who underwent extensive cardiovascular examination. Speckle-tracking echocardiography was employed to assess LV global longitudinal strain (LVGLS) and circumferential strain (GCS), and arterial stiffness was assessed by cardio-ankle vascular index (CAVI). Mean age was 62 ± 12 years, and 56% were men. CAVI as continuous variable was associated with abnormal LVGLS (>−18.6%) independent of cardiovascular risk factors and echocardiographic parameters [adjusted odds ratio (OR) 1.23, P = 0.027] but not with LVGCS. In sex-stratified analysis, more pronounced association between quartiles of CAVI and abnormal LVGLS was observed in women than in men (unadjusted OR = 6.43 in women and 2.46 in men for upper quartile vs. lower quartile; both P < 0.01). CAVI was significantly associated with abnormal LVGLS independent of cardiovascular risk factors in both sexes. However, after further adjustment for LV mass index and diastolic parameters, the independent association persisted only in women (adjusted OR 1.67, P = 0.007), but not in men (adjusted OR 1.14, P = 0.227).

Conclusion 

Increased arterial stiffness was independently associated with decreased LVGLS even without overt cardiovascular disease; a sex-specific pattern exists in the alteration of vascular-ventricular coupling, which might partially explain the greater susceptibility to HFpEF in women.
Clinical presentation, management, and 6-month outcomes in women with peripartum cardiomyopathy: an ESC EORP registry
Authors: Sliwa Karen , Petrie Mark C , van der Meer Peter , Mebazaa Alexandre , Hilfiker-Kleiner Denise , Jackson Alice M , Maggioni Aldo P , Laroche Cecile , Regitz-Zagrosek Vera , Schaufelberger Maria , Tavazzi Luigi , Roos-Hesselink Jolien W , Seferovic Petar , van Spaendonck-Zwarts Karin , Mbakwem Amam , Böhm Michael , Mouquet Frederic , Pieske Burkert , Johnson Mark R , Hamdan Righab , Ponikowski Piotr , Van Veldhuisen Dirk J , McMurray John J V , Bauersachs Johann
Published: May 2020

Aims 

We sought to describe the clinical presentation, management, and 6-month outcomes in women with peripartum cardiomyopathy (PPCM) globally.

Methods and results 

In 2011, >100 national and affiliated member cardiac societies of the European Society of Cardiology (ESC) were contacted to contribute to a global registry on PPCM, under the auspices of the ESC EURObservational Research Programme. These societies were tasked with identifying centres who could participate in this registry. In low-income countries, e.g. Mozambique or Burkina Faso, where there are no national societies due to a shortage of cardiologists, we identified potential participants through abstracts and publications and encouraged participation into the study. Seven hundred and thirty-nine women were enrolled in 49 countries in Europe (33%), Africa (29%), Asia-Pacific (15%), and the Middle East (22%). Mean age was 31 ± 6 years, mean left ventricular ejection fraction (LVEF) was 31 ± 10%, and 10% had a previous pregnancy complicated by PPCM. Symptom-onset occurred most often within 1 month of delivery (44%). At diagnosis, 67% of patients had severe (NYHA III/IV) symptoms and 67% had a LVEF ≤35%. Fifteen percent received bromocriptine with significant regional variation (Europe 15%, Africa 26%, Asia-Pacific 8%, the Middle East 4%, P < 0.001). Follow-up was available for 598 (81%) women. Six-month mortality was 6% overall, lowest in Europe (4%), and highest in the Middle East (10%). Most deaths were due to heart failure (42%) or sudden (30%). Re-admission for any reason occurred in 10% (with just over half of these for heart failure) and thromboembolic events in 7%. Myocardial recovery (LVEF > 50%) occurred only in 46%, most commonly in Asia-Pacific (62%), and least commonly in the Middle East (25%). Neonatal death occurred in 5% with marked regional variation (Europe 2%, the Middle East 9%).

Conclusion 

Peripartum cardiomyopathy is a global disease, but clinical presentation and outcomes vary by region. Just under half of women experience myocardial recovery. Peripartum cardiomyopathy is a disease with substantial maternal and neonatal morbidity and mortality.