bluuebunny/crossref_metadata_2025 huggingface dataset:
Functionalization of electronic, spin and optical properties of GeSe monolayer by substitutional doping: a first-principles study
Authors: Chakraborty Rajat , Ahmed Shahnewaz , Subrina Samia
Published: April 2021

Substitutional doping has traditionally been used to modulate the existing properties of semiconductors and introduce new exciting properties, especially in two-dimensional materials. In this work, we have investigated the impact of substitutional doping (using group III, IV, V, and VI dopants) on the structural, electronic, spin, and optical properties of GeSe monolayer by using first-principles calculations based on density functional theory. Our calculated binding energies, formation energies and phonon dispersion curves of the doped systems support their stability and hence the feasibility of physical realization. Our results further suggest that switching between metallic and semiconducting states of GeSe monolayer can be controlled by dopant atoms with a different number of valence electrons. The band gap of the semiconducting structures can be tuned within a range of 0.2864 eV to 1.17 eV by substituting with different dopants. In addition, most of the doped structures maintain the low effective mass, 0.20

m

0

to 0.59

m
0

for electron and 0.21

m
0

to 0.52

m
0

for hole, which ensures the enhanced transport properties of GeSe based electronic devices. Moreover, when Ge is substituted with group V dopants, a magnetic moment is introduced in an otherwise non-magnetic GeSe monolayer. The optical absorption coefficient of the doped structures can be significantly improved (>2×) in the visible and infrared regions. These intriguing results would encourage the applications of doped GeSe monolayer in next-generation electronic, optoelectronic and spintronic devices.
Radiomics analysis of chest CT to predict the overall survival for the severe patients of COVID-19 pneumonia
Authors: Xiao Feng , Sun Rongqing , Sun Wenbo , Xu Dan , Lan Lan , Li Huan , Liu Huan , Xu Haibo
Published: April 2021

Personalized assessment and treatment of severe patients with COVID-19 pneumonia have greatly affected the prognosis and survival of these patients. This study aimed to develop the radiomics models as the potential biomarkers to estimate the overall survival (OS) for the COVID-19 severe patients. A total of 74 COVID-19 severe patients were enrolled in this study, and 30 of them died during the follow-up period. First, the clinical risk factors of the patients were analyzed. Then, two radiomics signatures were constructed based on two segmented volumes of interest of whole lung area and lesion area. Two combination models were built depend on whether the clinic risk factors were used and/or whether two radiomics signatures were combined. Kaplan–Meier analysis were performed for validating two radiomics signatures and C-index was used to evaluated the predictive performance of all radiomics signatures and combination models. Finally, a radiomics nomogram combining radiomics signatures with clinical risk factors was developed for predicting personalized OS, and then assessed with respect to the calibration curve. Three clinical risk factors were found, included age, malignancy and highest temperature that influence OS. Both two radiomics signatures could effectively stratify the risk of OS in COVID-19 severe patients. The predictive performance of the combination model with two radiomics signatures was better than that only one radiomics signature was used, and became better when three clinical risk factors were interpolated. Calibration curves showed good agreement in both 15 d survival and 30 d survival between the estimation with the constructed nomogram and actual observation. Both two constructed radiomics signatures can act as the potential biomarkers for risk stratification of OS in COVID-19 severe patients. The radiomics+clinical nomogram generated might serve as a potential tool to guide personalized treatment and care for these patients.
Total loss measurement and simulation in a REBCO coated conductor carrying DC current in perpendicular AC magnetic field at various temperatures
Authors: Sun Yueming , Fang Jin , Sidorov Gennady , Li Quan , Badcock Rodney A , Long Nicholas J , Jiang Zhenan
Published: April 2021

In many high-temperature superconducting (HTS) applications, HTS coated conductors carry DC currents under external AC magnetic fields. There are two AC loss mechanisms in this situation: magnetization loss due to the external magnetic field and dynamic loss due to the interaction between the DC current and the external magnetic field. The sum of these two loss components is referred to as total loss. In this work, the total loss in a 4 mm wide REBCO coated conductor is measured under perpendicular AC magnetic fields up to 105 mT at 77 K, 70 K, and 65 K, with reduced DC current level, i (I
dc/I
c0), from 0.025 to 0.98, where I
dc is the transport DC current value and I
c0 is the self-field critical current of the coated conductor at each temperature. The experimental results show a good quantitative agreement with an analytical equation for each loss component, as well as 2D finite element modelling (FEM) results from
H
-formulation. For any given temperature, we observe that the total loss is mostly dominated by magnetization loss at i< 0.2, while dynamic loss makes a comparable, even greater contribution to total loss at i > 0.5. Electromagnetic analysis from the FEM modelling shows the evolution process of total loss, where the dynamic loss region and magnetization loss region vary across the conductor width at high magnetic fields or high DC current level. The simulation results also reveal the superposition of (positive) DC current and the anti-parallel (negative) shielding current, which occurs at high DC current level. The superposition drives the current density of one conductor edge to subcritical stage, and it leads to one-sided loss generation in each half-cycle. Our results provide a valuable reference for total loss behaviours in REBCO coated conductors.
Nonlinear contact behavior of HTS tapes during pancake coiling and CORC cabling
Authors: Wang Keyang , Gao Yuanwen , Luo Wei , Zhou Youhe , Nijhuis Arend
Published: April 2021

Both the pancake coiling and conductor on round core (CORC) cabling processes consist of winding second-generation high-temperature superconducting tape (REBCO) in a core. The contact behavior between the tape and the core during the winding process directly affects the critical current, cable flexibility, mechanical support and electrical contact resistance. Therefore, the winding process needs to be optimized to produce pancake coils and CORC cables with the desired electrical and mechanical properties. This paper comprehensively considers the role of the relaxation and Poisson effects. The theoretical model and the finite element model (FEM) for calculating the contact stress during the winding process are established, and a formula for the estimation of the contact force is proposed. The suitable winding pre-tension force, winding curvature radius of SCS2030 (2 mm width and 30

μ

m substrate thickness) and SCS4050 (4 mm width and 50

μ

m substrate thickness) of REBCO tapes are obtained and discussed by accounting for the relaxation effect and the critical current degradation limit. With consideration of the Poisson effect, the nonlinear contact behavior is investigated. In addition, the relaxation effect, Poisson effect and plasticity of the REBCO tape are taken into account in the FEM model. The results show that the axial strain in the REBCO layer during the winding process is related to the contact behavior. The greater the winding pre-tension force, the smaller the helical curvature radius, and the greater the contact force. The distribution of contact stress for several winding factors (winding pre-tension force, winding angle and the core radius) is divided into three contact types: the single-line contact, the double-line contact and the surface contact. The FEM model results are consistent with the theoretical evaluation and are more suitable for practical winding cases. This research is the basis for designing and optimizing pancake coils and CORC cables.
Highly accurate Gaussian process tomography with geometrical sets of coherent states
Authors: Teo Yong Siah , Park Kimin , Shin Seongwook , Jeong Hyunseok , Marek Petr
Published: April 2021

We propose a practical strategy for choosing sets of input coherent states that are near-optimal for reconstructing single-mode Gaussian quantum processes with output-state heterodyne measurements. We first derive analytical expressions for the mean squared-error that quantifies the reconstruction accuracy for general process tomography and large data. Using such expressions, upon relaxing the trace-preserving (TP) constraint, we introduce an error-reducing set of input coherent states that is independent of the measurement data or the unknown true process—the geometrical set. We numerically show that process reconstruction from such input coherent states is nearly as accurate as that from the best possible set of coherent states chosen with the complete knowledge about the process. This allows us to efficiently characterize Gaussian processes even with reasonably low-energy coherent states. We numerically observe that the geometrical strategy without trace preservation beats all nonadaptive strategies for arbitrary TP Gaussian processes of typical parameter ranges so long as the displacement components are not too large.
Frenkel pairs cause elastic softening in zirconia: theory and experiments
Authors: Kathiria Rushi , Wolf Dietrich E , Raj Rishi , Jongmanns Malte
Published: April 2021

Recent results from molecular dynamics simulations have shown that significant concentrations of Frenkel pairs can be introduced by the proliferation of phonons lying at the edge of the Brillouin zone and when above the Debye temperature. Following the work of Granato (2014 Eur. Phys. J. B
87 18) we extend those calculations to the influence of Frenkels on the elastic modulus. Significant softening is predicted which is confirmed by in situ measurements of the elastic modulus during flash. Frenkel pairs have been proposed to play a central role in the flash phenomena.
Transmutation of protons in a strong electromagnetic field
Authors: Wistisen T N , Keitel C H , Di Piazza A
Published: April 2021

The process of turning a proton into a neutron, positron and electron-neutrino in a strong plane-wave electromagnetic field is studied. This process is forbidden in vacuum and is seen to feature an exponential suppression factor which is non-perturbative in the field amplitude. The suppression is alleviated when the proton experiences a field strength of about ten times the Schwinger critical field in its rest frame or larger. Around this threshold the lifetime of the proton, in its rest frame, is comparable to the conventional neutron decay lifetime. As the field strength is increased, the proton lifetime becomes increasingly short. We investigate possible scenarios where this process may be observed in the laboratory using an ultra-intense laser and a high-energy proton beam with the conclusion, however, that it would be very challenging to observe this effect in the near future.
The role of chaotic and ordered trajectories in establishing Born’s rule
Authors: Tzemos A C , Contopoulos G
Published: April 2021

We study in detail the trajectories, ordered and chaotic, of two entangled Bohmian qubits when their initial preparation satisfies (or not) Born’s rule for various amounts of quantum entanglement. For any non zero value of entanglement ordered and chaotic trajectories coexist and the proportion of ordered trajectories increases with the decrease of the entanglement. In the extreme cases of zero and maximum entanglement we have only ordered and chaotic trajectories correspondingly. The chaotic trajectories of this model are ergodic, for any given value of entanglement, namely the limiting distribution of their points does not depend on their initial conditions. Consequently it is the ratio between ordered and chaotic trajectories which is responsible for the dynamical establishment (or not) of Born’s rule.
Inflation and cosmological constant
Authors: Bisabr Yousef
Published: April 2021

In construction of an inflationary model, one usually assumes that the matter sector of the gravitational action is minimally coupled to the background. It means that the matter (inflaton) part of the action is coupled with the same metric of the gravitational part. We elaborate on this assumption and investigate some of the consequences. We assume that the gravitational and the inflaton sectors belong to different units (or conformal frames). We show that this coupling can convert a single-field inflationary model into a two-field one with a mixed kinetic term. The energy-momentum tensor of the inflaton is therefore non-conserved due to the interaction with the conformal factor. This allows an energy exchange between the two fields and provides us with a mechanism for reduction of a large effective cosmological constant during inflation.
Parametric control of propagation of optical vortices through fibre ring resonators
Authors: Alexeyev C N , Barshak E V , Lapin B P , Vikulin D V , Yavorsky M A
Published: April 2021

In this paper, we have studied transmission of optical vortices (OVs) through ring resonators (RRs) based on multimode fibres. Using the formalism of transfer matrix we have obtained in the scalar approximation the analytical expressions for amplitudes of transmitted OVs with opposite topological charges (TCs) as functions of RR’s parameters. We have calculated the orbital angular momentum (OAM) of the outcoming field and shown that by changing such parameters one can efficiently control its TC and continuously change its OAM. We have established that TC and OAM feature wavelength-scale sensitivity to variations of the ring’s length. We have demonstrated that this ability of RRs to influence OAM is due to a multipass interference assisted with TC inversion in the coupling area. We have also studied the effect of losses on the transmission of OVs through RRs and established that by controlling the attenuation parameter one can also control the TC of the outcoming field. Finally, we have solved the problem of OV transmission within the frameworks of a fully vectorial approach that allows for the spin–orbit interaction (SOI) in fibres. We have shown that accounting the SOI does not alter the main properties of RRs established with the use of the scalar approximation theory. We have shown that RRs, which operate on OAM modes, can be used for emulation of the quantum logical X, Y, S, T and Z gates. This can be useful for optical simulation of quantum computations.
Dispersing and semi-flat bands in the wide band gap two-dimensional semiconductor bilayer silicon oxide
Authors: Kremer Geoffroy , Camilo Alvarez-Quiceno Juan , Pierron Thomas , González César , Sicot Muriel , Kierren Bertrand , Moreau Luc , Rault Julien E , Le Fèvre Patrick , Bertran François , Dappe Yannick J , Coraux Johann , Pochet Pascal , Fagot-Revurat Yannick
Published: April 2021

Epitaxial bilayer silicon oxide is a transferable two-dimensional material predicted to be a wide band gap semiconductor, with potential applications for deep UV optoelectronics, or as a building block of van der Waals heterostructures. The prerequisite to any sort of such applications is the knowledge of the electronic band structure, which we unveil using angle-resolved photoemission spectroscopy and rationalize with the help of density functional theory (DFT) calculations. We discover dispersing bands related to electronic delocalization within the top and bottom planes of the material, with two linear crossings reminiscent of those predicted in bilayer AA-stacked graphene, and semi-flat bands stemming from the chemical bridges between the two planes. This band structure is robust against exposure to air, and can be controlled by exposure to oxygen. We provide an experimental lower-estimate of the band gap size of 5 eV and predict a full gap of 7.36 eV using DFT calculations.
Effect of carbon nanotubes on the electrical, thermal, mechanical properties and crystallization behavior of continuous carbon fiber reinforced polyether-ether-ketone composites
Authors: Qiao Liang , Zhu Kaili , Tan Hongsheng , Yan Xu , Zheng Lihang , Dong Shuhua
Published: April 2021

The continuous carbon fiber reinforced Polyether-ether-ketone (PEEK) prepreg tapes with the addition of carbon nanotubes (CNTs) were prepared by a wet powder impregnation process. Their electrical conductivity, thermal conductivity, the tensile properties, dynamic mechanical behavior, fracture morphology and crystallization melting behavior were investigated. The results show that, the electrical conductivity (σ), thermal conductivity (λ), tensile strength (σ
t) and interfacial adhesion of the prepreg tapes were obviously improved with the addition of CNTs. When CNT content was 1.0 wt%, the σ of CNT/CCF/PEEK prepreg tapes in the 0° direction reached a maximum value of 0.701 s cm−1, which was increased 165% than that of CCF/PEEK prepreg tapes. The λ reached 1.053 W m−1·K−1, which was improved by 12.14%. The tensile strength was 1489 MPa, which was increased by 16.4%. The results of SEM images show that the interface adhesion between the fiber and the matrix is good. The results of DMA indicate that, the capability of deformation resistance of the prepreg tapes were further improved with the addition of CNTs. When the temperature was 280 °C, the decline rate of E′ of 1.0 wt% CNT/CCF/PEEK prepreg tapes were 3.58%. The results of DSC indicate that, the T
c of CNT/CCF/PEEK prepreg tapes moved to high temperature after adding CNTs, which indicate that CNTs played a role of heterogeneous nucleation in the PEEK matrix.
Experimental and numerical study for direct powder bed selective laser processing (sintering/melting) of silicon carbide ceramic
Authors: Montón Alejandro , Abdelmoula Mohammed , Küçüktürk Gökhan , Maury Francis , Grossin David , Ferrato Marc
Published: April 2021

The study was carried out to investigate the manufacturing possibility of Silicon Carbide (SiC) by direct Powder Bed Selective Laser Processing (PBSLP) experimentally and numerically. The experimental study was carried out by means of PBSLP while the numerical study was accomplished by developing a CFD model. The CFD model simulates accurately realistic conditions of the PBSLP process. A user-defined code, that describes the process parameters such as laser power, scanning speed, scanning strategies, and hatching distance has been developed and compiled to ANSYS FLUENT 2020 R1. Also, the model was validated with the available published data from the literature. The model was used to deeply analyse and support the results obtained through the experimental runs. Different values of laser power and scanning speeds with scanning strategy in the form of a continuous linear pattern and rotated by 90 degrees between layers were studied. The laser power is ranging from 52W to 235 W while the scanning speed is ranging from 300 to 3900 mm s−1. The results showed that the direct PBSLP of SiC is possible with the optimization of the process parameters. Layer thickness and hatching distance are the most important parameters that needed to be optimized. Also, the laser power and scanning speed needed to be adjusted so that the scanning temperature was between the sintering and the decomposition limits. The good agreement between experimental and simulation results proved the power and ability of the developed CFD model to be a useful tool to analyse and optimize future experimental data.
Response of shear in bulk orientations of charged DNA rods: Taylor- and gradient-banding
Authors: Kang Kyongok
Published: April 2021

Shear-induced instabilities leading to various kinds of inhomogeneous flow profiles play an important role in the processing of complex fluids, ranging from polymeric materials to various types of biological systems. In previously studied systems, either Taylor banding, or gradient banding, or fracture is observed. In the present work we study a system for which all instabilities occur in orientation textures (OTs), and where Taylor banding occurs simultaneously with gradient banding. The system here consists of crowded suspensions of long and thin DNA-based rods (at a low ionic strength of 0.16 mM salt), where the applied shear rate is systematically varied, for concentrations well below and above the glass-transition concentration (12.4 mg ml−1). To simultaneously measure the velocity profile along the gradient direction, in fracture and gradient banding, the optical cell is placed in a specially designed heterodyne light scattering set up, where the scattering volume can be scanned across the cell gap. The results confirm that Taylor bands and gradient banding occur in the concentration of DNA rods and applied shear-rates (35–80 s−1). Taylor bands clearly show the flow access in vorticity-direction, while the gradient banding is rearranged as thick rolling flows of OTs, at the middle shear-rate (50 s−1). The observations can be then useful to facilitate other biological complex fluids and the glass-forming liquids.
Mapping incentives for sustainable water use: global potential, local pathways
Authors: Wight Charles , Garrick Dustin , Iseman Tom
Published: April 2021

Competition for freshwater resources is intensifying water scarcity and its impacts on people, economies, and the environment, posing a growing challenge for sustainable development. Meeting these challenges will require incentives to encourage sustainable water use. Prior calls to shift from supply-driven solutions to a soft path of demand management (pricing, markets, behavioral changes) have encountered stubborn obstacles. We undertake a multi-scale assessment of water reallocation and investment in water conservation technologies to understand their potential and limits for addressing different drivers of water scarcity. Our model identifies what drives water scarcity at the subbasin scale, and examines two prominent responses to these drivers. Our analysis distinguishes different types of water scarcity based on the demands for water and their timing, creating nine (9) categories of water competition, which can overlap. Water demand within agriculture contributes to scarcity in 94% of the basins experiencing scarcity, concentrated in central USA, Spain, and India. Urbanization has led to competition between cities and agriculture in 1,596 of 3,057 subbasins (52%). We examine how different institutional mechanisms (incentive-based water reallocation) and technologies (investment in water conservation technologies) can address these different types of water scarcity. This study builds on several local and high-resolution models demonstrating the potential to increase the economic efficiency (and marginal productivity) of water use. The gap between potential and implementation is high, however. Efforts to bridge this gap in priority geographies can link modelling advances with the design of pathways that combine incentives with robust water accounting, caps on water extraction, and enforcement capacity at multiple scales.
The path towards 1 µm monocrystalline Zn3P2 films on InP: substrate preparation, growth conditions and luminescence properties
Authors: Zamani Mahdi , Stutz Elias , Escobar Simon , Zamani Reza R , Paul Rajrupa , Leran Jean-Baptiste , Dimitrievska Mirjana , Fontcuberta i Morral Anna
Published: April 2021

Semiconductors made with earth abundant elements are promising as absorbers in future large-scale deployment of photovoltaic technology. This paper reports on the epitaxial synthesis of monocrystalline zinc phosphide

Z

n

3

P

2

films using molecular beam epitaxy with thicknesses up to 1 µm thickness on InP (100) substrates, as demonstrated by high resolution transmission electron microscopy and x-ray diffraction. We explain the mechanisms by which thick monocrystalline layers can form. We correlate the crystalline quality with the optical properties by photoluminescence at 12 K. Polycrystalline and monocrystalline films exhibit dissimilar photoluminescence below the bandgap at 1.37 and 1.30 eV, respectively. Band edge luminescence at 1.5 eV is only detected for monocrystalline samples. This work establishes a reliable method for fabricating high-quality

Z

n

3

P

2

thin films that can be employed in next generation photovoltaic applications.
The Dual Reality of No-Rights
Authors: McBride Mark
Published: April 2021

In a fascinating recent debate in the pages of this journal, several legal philosophers have clashed over the very existence and nature of the deontic position of Hohfeldian no-rights. While the debate has many strands, and has become increasingly intricate, I want to focus on one—or, the—central strand, a strand the importance of which cannot sensibly be questioned. Countering Andrew Halpin, I shall vindicate the dual nature of the claim-right/no-right relation, recently articulated by Matthew Kramer. In so doing, I go far beyond anything Kramer has currently ventured. Ultimately, then, I am countering Heidi Hurd & Michael Moore by vindicating the existence of Hohfeldian liberties. The Hohfeldian table emerges unmarked.
Out of the Qinghai–Tibetan Plateau and rapid radiation across Eurasia for Allium section Daghestanica (Amaryllidaceae)
Authors: Li Min-Jie , Yu Huan-Xi , Guo Xian-Lin , He Xing-Jin
Published: April 2021

The disjunctive distribution (Europe–Caucasus–Asia) and species diversification across Eurasia for the genus Allium sect. Daghestanica has fascinating attractions for researchers aiming to understanding the development and history of modern Eurasia flora. However, no any studies have been carried out to address the evolutionary history of this section. Based on the nrITS and cpDNA fragments (trnL–trnF and rpl32–trnL), the evolutionary history of the third evolutionary line (EL3) of the genus Allium was reconstructed and we further elucidated the evolutionary line of sect. Daghestanica under this background. Our molecular phylogeny recovered two highly supported clades in sect. Daghestanica: the Clade I includes Caucasian–European species and Asian A. maowenense, A. xinlongense and A. carolinianum collected in Qinghai; the Clade II comprises Asian yellowish tepal species, A. chrysanthum, A. chrysocephalum, A. herderianum, A. rude and A. xichuanense. The divergence time estimation and biogeography inference indicated that Asian ancestor located in the Qinghai–Tibetan Plateau (QTP) and the adjacent region could have migrated to Caucasus and Europe distributions around the Late Miocene and resulted in further divergence and speciation; Asian ancestor underwent the rapid radiation in the QTP and the adjacent region most likely due to the heterogeneous ecology of the QTP resulted from the orogeneses around 4–3 million years ago (Mya). Our study provides a picture to understand the origin and species diversification across Eurasia for sect. Daghestanica.
Proteome characterization of two contrasting soybean genotypes in response to different phosphorus treatments
Authors: Zhao Hongyu , Yang Ahui , Kong Lingjian , Xie Futi , Wang Haiying , Ao Xue
Published: April 2021

Phosphorus (P) is an essential element for the growth and development of plants. Soybean (Glycine max) is an important food crop that is grown worldwide. Soybean yield is significantly affected by P deficiency in the soil. To investigate the molecular factors that determine the response and tolerance at low-P in soybean, we conducted a comparative proteomics study of a genotype with low-P tolerance (Liaodou 13, L13) and a genotype with low-P sensitivity (Tiefeng 3, T3) in a paper culture experiment with three P treatments, i.e. P-free (0 mmol·L−1), low-P (0.05 mmol·L−1) and normal-P (0.5 mmol·L−1). A total of 4126 proteins were identified in roots of the two genotypes. Increased numbers of differentially expressed proteins (DEPs) were obtained from low-P to P-free conditions compared to the normal-P treatment. All DEPs obtained in L13 (660) were upregulated in response to P deficiency, while most DEPs detected in T3 (133) were downregulated under P deficiency. Important metabolic pathways such as oxidative phosphorylation, glutathione metabolism and carbon metabolism were suppressed in T3, which could have affected the survival of the plants in P-limited soil. In contrast, L13 increased the metabolic activity in the 2-oxocarboxylic acid metabolism, carbon metabolism, glycolysis, biosynthesis of amino acids, pentose phosphatase, oxidative phosphorylation, other types of O-glycan biosynthesis and riboflavin metabolic pathways in order to maintain normal plant growth under P deficiency. Three key proteins I1KW20 (prohibitins), I1K3U8 (alpha-amylase inhibitors) and C6SZ93 (alpha-amylase inhibitors) were suggested as potential biomarkers for screening soybean genotypes with low-P tolerance. Overall, this study provides new insights into the response and tolerance to P deficiency in soybean.
No neighbour-induced increase in root growth of soybean and sunflower in mesh-divider experiments after controlling for nutrient concentration and soil volume
Authors: Chen Bin J W , Huang Li , During Heinjo J , Wang Xinyu , Wei Jiahe , Anten Niels P R
Published: April 2021

Root competition is a key factor determining plant performance, community structure and ecosystem productivity. To adequately estimate the extent of root proliferation of plants in response to neighbours independently of nutrient availability, one should use a set-up that can simultaneously control for both nutrient concentration and soil volume at plant individual level. With a mesh-divider design, which was suggested as a promising solution for this problem, we conducted two intraspecific root competition experiments: one with soybean (Glycine max) and the other with sunflower (Helianthus annuus). We found no response of root growth or biomass allocation to intraspecific neighbours, i.e. an ‘ideal free distribution’ (IFD) norm, in soybean; and even a reduced growth as a negative response in sunflower. These responses are all inconsistent with the hypothesis that plants should produce more roots even at the expense of reduced fitness in response to neighbours, i.e. root over-proliferation. Our results suggest that neighbour-induced root over-proliferation is not a ubiquitous feature in plants. By integrating the findings with results from other soybean studies, we conclude that for some species this response could be a genotype-dependent response as a result of natural or artificial selection, or a context-dependent response so that plants can switch from root over-proliferation to IFD depending on the environment of competition. We also critically discuss whether the mesh-divider design is an ideal solution for root competition experiments.
Trail Making Test Normative Data for the German Older Population
Authors: Specka Michael , Weimar Christian , Stang Andreas , Jöckel Karl-Heinz , Scherbaum Norbert , Hoffmann Sarah Sanchez , Kowall Bernd , Jokisch Martha
Published: April 2021

Objective

We provide normative data for the Trail Making Test (TMT)-A and B and the derived scores B − A and B/A, for the German general population aged 57–84 years.

Methods

Data were derived from the third examination of the population-based Heinz Nixdorf Recall study. We excluded participants with a history of dementia or stroke, a depression score above cutoff (CES-D Center for Epidemiologic Studies Depression Scale score ≥ 18), or mild cognitive impairment according to a neurocognitive test battery. The normative sample (n = 2,182) was stratified by age, using the interval superposition approach, and by three levels of educational attainment (up to 10 years of schooling; >10 years of schooling; and university degree).

Results

We tabulated test performance scores at percentage rank thresholds 5, 10, 15, 20, 25, 50, 75, and 90. In multiple linear regression, TMT-A performance declined by 1 s each year of life, and TMT-B performance by 3 s; educational level had an impact of up to 30 s in TMT-B. TMT-B/A was only weakly associated with age and education. TMT-B and B − A correlated r = 0.96. Completion of the TMT-B within the time limit of 300 s was not achieved by 10.9% of participants >74 years, and especially by those >74 years who were on the lowest educational level (13.9%).

Conclusions

For TMT-A, TMT-B, and B − A, the narrow age categorization and distinction between three educational levels proved meaningful. The 300 s limit for the TMT-B impedes the identification of thresholds for very low performance in this age group and needs reconsideration.
Updates to HCOP: the HGNC comparison of orthology predictions tool
Authors: Yates Bethan , Gray Kristian A , Jones Tamsin E M , Bruford Elspeth A
Published: April 2021

Multiple resources currently exist that predict orthologous relationships between genes. These resources differ both in the methodologies used and in the species they make predictions for. The HGNC Comparison of Orthology Predictions (HCOP) search tool integrates and displays data from multiple ortholog prediction resources for a specified human gene or set of genes. An indication of the reliability of a prediction is provided by the number of resources that support it. HCOP was originally designed to show orthology predictions between human and mouse but has been expanded to include data from a current total of 20 selected vertebrate and model organism species. The HCOP pipeline used to fetch and integrate the information from the disparate ortholog and nomenclature data resources has recently been rewritten, both to enable the inclusion of new data and to take advantage of modern web technologies. Data from HCOP are used extensively in our work naming genes as the Vertebrate Gene Nomenclature Committee (https://vertebrate.genenames.org).
A novel systematic approach for cancer treatment prognosis and its applications in oropharyngeal cancer with microRNA biomarkers
Authors: He Shenghua , Lian Chunfeng , Thorstad Wade , Gay Hiram , Zhao Yujie , Ruan Su , Wang Xiaowei , Li Hua
Published: April 2021

Motivation

Predicting early in treatment whether a tumor is likely to respond to treatment is one of the most difficult yet important tasks in providing personalized cancer care. Most oropharyngeal squamous cell carcinoma (OPSCC) patients receive standard cancer therapy. However, the treatment outcomes vary significantly and are difficult to predict. Multiple studies indicate that microRNAs (miRNAs) are promising cancer biomarkers for the prognosis of oropharyngeal cancer. The reliable and efficient use of miRNAs for patient stratification and treatment outcome prognosis is still a very challenging task, mainly due to the relatively high dimensionality of miRNAs compared to the small number of observation sets; the redundancy, irrelevancy and uncertainty in the large amount of miRNAs; and the imbalanced observation patient samples.

Results

In this study, a new machine learning-based prognosis model was proposed to stratify subsets of OPSCC patients with low and high risks for treatment failure. The model cascaded a two-stage prognostic biomarker selection method and an evidential K-nearest neighbors classifier to address the challenges and improve the accuracy of patient stratification. The model has been evaluated on miRNA expression profiling of 150 oropharyngeal tumors by use of overall survival and disease-specific survival as the end points of disease treatment outcomes, respectively. The proposed method showed superior performance compared to other advanced machine-learning methods in terms of common performance quantification metrics. The proposed prognosis model can be employed as a supporting tool to identify patients who are likely to fail standard therapy and potentially benefit from alternative targeted treatments.

 

Availability and implementation: Code is available in  https://github.com/shenghh2015/mRMR-BFT-outcome-prediction.
Territorial and institutional obduracy in regional transition: politicising the case of Flanders’ energy distribution system
Authors: Juwet Griet , Deruytter Laura
Published: April 2021

This case study unravels the ambiguous position of public energy distributor Fluvius in dealing with strategic regional transition challenges. It enriches current understandings of spatial transition dimensions and of public regime actors’ role in transitions, by unravelling the territorial and institutional embeddedness of regional energy distribution systems. We disentangle three controversies in Flemish energy distribution, centred around the spatial concepts of density, spatial selectivity and socio-spatial redistribution. This spatial lens reveals the implicit spatial logics and inherently political character of transforming regional distribution systems. We conclude that a fundamental energy transition requires more inclusive governance, and an ambitious spatial transition vision.
Kidney involvement in multisystem inflammatory syndrome in children: a pediatric nephrologist’s perspective
Authors: Sethi Sidharth Kumar , Rana Abhyuday , Adnani Harsha , McCulloch Mignon , Alhasan Khalid , Sultana Azmeri , Safadi Rama , Agrawal Nirav , Raina Rupesh
Published: April 2021

The initial report of the multisystem inflammatory syndrome in children (MIS-C) was from the UK in April 2020; since then, cases have been reported worldwide. Renal involvement has been seen commonly, ranging from 10% to 46%. Kidney involvement following severe acute respiratory syndrome coronavirus 2 infection in children with MIS-C is more common than initially thought and is associated with higher morbidity and mortality. There are several reports of a direct viral tropism of coronavirus disease 2019 and MIS-C-associated renal damage. This study’s objective was to systematically review the current understanding of kidney involvement in children suffering from MIS-C. Based on our systemic literature search, 19 studies have either partially or fully discussed kidney involvement in MIS-C patients. Furthermore, we discuss the multifactorial pathogenesis contributing to acute kidney injury (AKI) development in MIS-C. The current review gives a pediatric nephrologist’s perspective of the renal involvement in MIS-C, the incidence of AKI, the pathophysiology of AKI in MIS-C and the proposed therapeutic regimens available, including the need for kidney replacement therapy for a child with AKI associated with MIS-C. As the disease is rapidly evolving, more detailed clinical prospective studies are required to understand MIS-C and its role in AKI better.
High-Sensitivity Cardiac Troponin T for the Detection of Myocardial Injury and Risk Stratification in COVID-19
Authors: De Michieli Laura , Ola Olatunde , Knott Jonathan D , Akula Ashok , Mehta Ramila A , Hodge David O , Dworak Marshall , Yang Eric H , Gharacholou Michael , Singh Gurpreet , Singh Ripudamanjit , Gulati Rajiv , Jaffe Allan S , Sandoval Yader
Published: April 2021

Background

Limited data exist on high-sensitivity cardiac troponin (hs-cTn) for risk-stratification in COVID-19.

Methods

We conducted a multicenter, retrospective, observational, US-based study of COVID-19 patients undergoing hs-cTnT. Outcomes included short-term mortality (in-hospital and 30-days post-discharge) and a composite of major adverse events, including respiratory failure requiring mechanical ventilation, cardiac arrest, and shock within the index presentation and/or mortality during the index hospitalization or within 30-days post-discharge.

Results

Among 367 COVID-19 patients undergoing hs-cTnT, myocardial injury was identified in 46%. They had a higher risk for mortality (20% vs 12%, P < 0.0001; unadjusted HR 4.44, 95% CI 2.13–9.25, P < 0.001) and major adverse events (35% vs. 11%, P < 0.0001; unadjusted OR 4.29, 95% CI 2.50–7.40, P < 0.0001). Myocardial injury was associated with major adverse events (adjusted OR 3.84, 95% CI 2.00–7.36, P < 0.0001) but not mortality. Baseline (adjusted OR 1.003, 95% CI 1.00–1.007, P = 0.047) and maximum (adjusted OR 1.005, 95% CI 1.001–1.009, P = 0.0012) hs-cTnT were independent predictors of major adverse events. Most (95%) increases were due to myocardial injury, with 5% (n = 8) classified as type 1 or 2 myocardial infarction. A single hs-cTnT <6 ng/L identified 26% of patients without mortality, with a 94.9% (95% CI 87.5–98.6) negative predictive value and 93.1% sensitivity (95% CI 83.3–98.1) for major adverse events in those presenting to the ED.

Conclusions

Myocardial injury is frequent and prognostic in COVID-19. While most hs-cTnT increases are modest and due to myocardial injury, they have important prognostic implications. A single hs-cTnT <6 ng/L at presentation may facilitate the identification of patients with a favorable prognosis.
Failing systemic right ventricle in a patient with dextrocardia and complex congenitally corrected transposition of the great arteries: a case report of successful transvenous cardiac resynchronization therapy
Authors: Nederend Marieke , van Erven Lieselot , Zeppenfeld Katja , Vliegen Hubert W , Egorova Anastasia D
Published: April 2021

Background 

Patients with congenitally corrected transposition of the great arteries (ccTGA) are prone to the development of advanced atrio-ventricular block requiring chronic ventricular pacing. The morphological right ventricle (RV) often develops systolic dysfunction as it is unable to withstand the chronic pressure overload it is exposed to when supporting the systemic circulation.

Case summary 

A 56-year-old woman with dextrocardia and complex ccTGA with a history of dual-chamber implantable cardioverter-defibrillator (DDD-ICD, high degree atrio-ventricular-block and syncopal ventricular tachycardia), presented with progressive heart failure and symptomatic atrial arrhythmias. She underwent a successful ablation and concomitant invasive haemodynamic evaluation of potential alternative/biventricular pacing modalities. During biventricular pacing, the QRS narrowed and the systemic RV intraventricular pressure (Dp/Dt) increased with 30%. She underwent a successful transvenous upgrade to cardiac resynchronization therapy (CRT). The electrocardiogram post-implantation showed biventricular capture and patient showed subjective and objective clinical improvement.

Discussion 

Systemic RV dysfunction in ccTGA can be aggravated by chronic pacing-induced dyssynchrony, contributing to progression of heart failure in this patient group. Transvenous CRT is feasible in ccTGA anatomy and may be pursued in order to improve or preserve the functional status of pacing-dependent ccTGA patients. Invasive haemodynamic contractility evaluation can help assess the potential benefit of CRT in patients with complex anatomy.
A case report: Amplatzer occluder device closure of an iatrogenic ventricular septal defect following radiofrequency ablation
Authors: Michaelis Anna , Dähnert Ingo , Riede Frank-Thomas , Paetsch Ingo , Jahnke Cosima , Paech Christian
Published: April 2021

Background

Interventricular septal perforation is an extremely rare complication of radiofrequency ablation (RFA), with an incidence of 1%. The most common mechanism is a ‘steam pop’, which can be described as ‘mini-explosions’ of gas bubbles. Data for percutaneous repair of cardiac perforations due to RFA are limited.

Case summary

A 78-year-old female patient was referred to our department for the treatment of two iatrogenic ventricular septal defects (VSDs) following radiofrequency ablation (RFA) of premature ventricular contractions. One week post-ablation, chest pain and progressive dyspnoea occurred. Transthoracic echocardiography detected a VSD, diameter 10 mm. Hence, iatrogenic, RFA-related myocardial injury was considered the most likely cause of VSD, and the patient was referred to our tertiary care centre for surgical repair. Cardiovascular magnetic resonance (CMR) imaging demonstrated border-zone oedema of the VSD only and confirmed the absence of necrotic tissue boundaries, and the patient was deemed suitable for percutaneous device closure. Laevocardiography identified an additional, smaller muscular defect that cannot be explained by analysing the Carto-Map. Both defects could be successfully closed percutaneously using two Amplatzer VSD occluder devices.

Discussion

In conclusion, this case demonstrates a successful percutaneous closure of a VSD resulting from RFA using an Amplatzer septal occluder device. CMR might improve tissue characterization of the VSD borders and support the decision if to opt for interventional or surgical closure.
Suction thrombectomy of a massive, hypermobile (type C) right atrial thrombus: a case report
Authors: Reddy Pavan K V , Kwan Tak , Latouff Omar , Patel Apurva
Published: April 2021

Background

Right atrial thrombus (RAT) may be managed according to morphology and aetiology, i.e. Type A thrombi (‘clot-in-transit’, hypermobile) are managed with thrombolytics and surgical embolectomy due to high risk of embolization; Type B thrombi (broad-based, globular) may be managed medically as they will very likely maintain a benign course. Experience with management of a Type C thrombus (hypermobile but also broad-based) has not been explicitly described in the literature.

Case summary

A 25-year-old man with history of leukaemia with prior right subclavian vein chemoport is found to have massive RAT. Multimodal imaging shows a hypermobile mass attached to the right atrial lateral wall inferior to superior vena cava and prolapsing into right ventricle in diastole. Given the thrombus morphology and likely propagation from subclavian port, risk of catastrophic embolization was deemed high and as such, intervention was indicated. Systemic anticoagulation was considered but deferred due to theoretical risk of dissolving the thrombus stalk leading to embolization. Surgical thrombectomy was offered but the patient declined. Due to evidence for success in RAT, the AngioVac System: Generation 3 (Angiodynamics, Inc., Latham, NY, USA) was chosen for intervention. The RAT was successfully removed without any complication.

Discussion

AngioVac suction thrombectomy is a safe alternative option for removal of a Type C, massive, hypermobile RAT.
Do patients who have newly identified prediabetes lose weight in the following year?
Authors: Varghai Nayyer Homa , Rothberg Michael B , Nathan Cassandra , Pfoh Elizabeth R
Published: April 2021

Background

Identifying a window of opportunity when patients are motivated to lose weight might improve the effectiveness of weight loss counseling. The onset of chronic disease could create such a window.

Objective

To determine whether identifying prediabetes was associated with subsequent weight loss.

Methods

Our retrospective cohort study included adults with obesity and a primary care visit between 2015 and 2017. Data were collected and analysed in 2019/2020. We compared patients who developed prediabetes [haemoglobin A1c (HbA1c) ≥5.7 and <6.5] to patients with a normal HbA1c (<5.7). We ran linear regression models to identify the association between identifying prediabetes and percent body mass index (BMI) change at 6 and 12 months. The adjusted model controlled for demographic characteristics at baseline, Charlson comorbidity score, and metformin, antipsychotic, antidepressant and antiobesity medication prescribed in either the first 3 months (for the 6-month outcome) or first 9 months (for 12-month outcome) and clustering within physician.

Results

Of 11 290 participants, 43% developed prediabetes. At 6 months, 15% of the prediabetes group lost ≥5% of their BMI compared with 13% of the comparison group. The results were similar at 12 months with 18% of the prediabetes group losing ≥5% of their BMI compared with 17%. The prediabetes group lost a higher percentage of their BMI (β = −0.7% versus −0.3% at 6 months and β = −0.5% versus 0.01% at 12 months).

Conclusions

While the percent of BMI change was small, patients with newly identified prediabetes lost more weight than a comparison group.