bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical value of the 20% logistic EuroSCORE cut-off for selecting TAVI candidates: a single-centre cohort study analysis
Authors: Imnadze Guram , Hofmann Steffen , Billion Michael , Ferdosi Abbas , Kowalski Marek , Rajab Ehab , Bramlage Karin , Bramlage Peter , Warnecke Henning , Franz Norbert
Published: February 2020

Background

A logistic European System for Cardiac Operative Risk Evaluation (logEuroSCORE) ≥20% is frequently recognised as a finite criteria for transcatheter aortic valve implantation (TAVI) reimbursement, despite guideline modifications to reflect the appropriacy of TAVI in selected lower-risk patients. The aim was to evaluate the clinical value of this threshold cut-off in TAVI patients and to identify factors associated with mortality in those below this threshold.

Methods

We analysed data from a single-centre, German, observational, TAVI-patient registry, gathered between 2008 and 2016. Patients were stratified by logEuroSCORE (≥ or <20%) for comparisons. Logistic regression was performed to identify predictors of mortality at 1 year, with this analysis used to generate a calculated (‘real’) risk value for each patient.

Results

1679 patients (logEuroSCORE <20%: n=789; logEuroSCORE ≥20%: n=890) were included. LogEuroSCORE <20% patients were significantly younger (80.1 vs 81.6 years; p<0.001) and less comorbid than logEuroSCORE ≥20% patients, with a higher rate of transfemoral TAVI (35.6% vs 26.1%; p<0.001) and predilation (70.0% vs 63.3%; p=0.004). Patients with a logEuroSCORE <20% experienced more vascular complications (3.4% vs 1.5%; p=0.010). One-year survival was 88.3% in the logEuroSCORE <20% and 81.8% in the logEuroSCORE ≥20% group (p=0.005), with the calculated mortality risk falling within 2% of the logEuroSCORE in just 12.9% of patients. In the logEuroSCORE <20% group, only coronary artery disease was significantly predictive of 1-year mortality (OR 2.408; 95% CI 1.361 to 4.262; p=0.003).

Conclusions

At our institution, patients with a logEuroSCORE <20% selected for TAVI have excellent outcomes. The decision not to reimburse TAVI in such patients may be viewed as inappropriate.
Clinical and echocardiographic characteristics of individuals aged 75/76 years old with screening-detected elevated NT-proBNP levels
Authors: Al-Khalili Faris , Kemp-Gudmundsdottir Katrin , Svennberg Emma , Fredriksson Tove , Frykman Viveka , Friberg Leif , Rosenqvist Mårten , Engdahl Johan
Published: February 2020

Background

High plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) indicate increased probability of congestive heart failure (CHF) and atrial fibrillation (AF) and are associated with poor prognosis.

Objective

We aimed to describe the clinical and echocardiographic characteristics of a population of individuals aged 75/76 years old with NT-proBNP ≥900 ng/L without previously known CHF or AF.

Methods

All individuals aged 75/76 years in the Stockholm region were randomised to a screening study for AF. Half of them were invited to screening. Of those invited, 49.5% agreed to participate. Individuals with NT-proBNP ≥900 ng/L without known CHF were invited for further clinical evaluation.

Results

Among 6315 participants without AF who had NT-proBNP sampled, 102 without previously known CHF had ≥900 ng/L. Of these, 93 completed further clinical investigations. In the population that was clinically investigated, 53% were female, and the median NT-proBNP was 1200 ng/L. New AF was found in 28 (30%). The NT-proBNP value in this group was not significantly different from those where AF was not detected (median 1285 vs 1178 ng/L). Patients with newly detected AF had larger left atrial volume and higher pulmonary artery pressure than those without AF. Preserved left ventricular ejection fraction (≥50%) was found in 86% of the participants, mid-range ejection fraction (40%–49%) in 3.2% and reduced ejection fraction (<40%) in 10.8%. Thirteen patients (14%) had other serious cardiac disorders that required medical attention.

Conclusion

Elderly individuals with NT-proBNP levels ≥900 ng/L constitute a population at high cardiovascular risk even in the absence of diagnosed CHF or AF, and therefore merit further investigation.
A self-calibrating, double-ratio method to test tau lepton universality in W boson decays at the LHC
Authors: Dysch S. , Wyatt T. R.
Published: February 2020

Measurements in $$W^+W^-$$W+W- events at LEP2 and in B hadron semileptonic decays at B factories and LHCb provide intriguing hints of a violation of lepton universality in the charged current coupling of tau leptons relative to those for electrons and muons. We propose a novel, self-calibrating method to test tau lepton universality in W boson decays at the LHC. We compare directly the ratio of the numbers of selected $$\ell \tau _{\mathrm {\,had}}$$ℓτhad and $$e\mu $$eμ final states in di-leptonic top quark pair events with that in $$Z/\gamma ^*\rightarrow \tau \tau $$Z/γ∗→ττ events. Here $$\ell =e\ {\mathrm {or}}\ \mu $$ℓ=eorμ and $$\tau _{\mathrm {\,had}}$$τhad is a candidate semi-hadronic tau decay. This “double-ratio” cancels to first order sensitivity to systematic uncertainties on the reconstruction of e, $$\mu $$μ, and $$\tau $$τ leptons, thus improving very significantly the precision to which tau lepton universality can be tested in W boson decay branching ratios at the LHC. Using particle-level Monte Carlo events, and a parameterised simulation of detector performance, we demonstrate the effectiveness of the method and estimate the most significant residual sources of uncertainty arising from experimental and phenomenological systematics. Our studies indicate that a single LHC experiment precision on the tau lepton universality test of around 1.4% is achievable with a data set of $$\int \!\! L\, \hbox {\,d}t$$∫Ldt = 140 $$\mathrm {fb}^{-1}$$fb-1 at $${\sqrt{s}}~=~13~\hbox {TeV}$$s=13TeV. This would improve significantly upon the precision of 2.5% on the four-experiment combined LEP2 measurements. If the central value of the proposed new measurement were equal to the central value of the LEP2 measurement this would yield an observation of BSM physics at a significance level of around 5$$\sigma $$σ.
The horizon of the McVittie black hole: on the role of the cosmic fluid modeling
Authors: Gregoris Daniele , Ong Yen Chin , Wang Bin
Published: February 2020

In this paper, we investigate the existence and time evolution of the cosmological and event horizons in a McVittie universe whose expansion is driven by the Redlich–Kwong, (Modified) Berthelot, Dieterici, and Peng–Robinson fluids, respectively. The equations of state of these fluids are rich enough to account for both exotic and regular, as well as ideal and non-ideal matter contents of the universe. We show that the cosmological horizon is expanding, while the event horizon is shrinking along the cosmic time evolution. The former achieves larger size for regular types of matter, contrary to the latter. The strength of interactions within the cosmic fluid are shown to play a more important role in affecting the evolution of the event horizon, rather than of the cosmological horizon in the case of a singularity-free universe. While the cosmological horizon always exists during the time evolution, the event horizon can exist only when a certain relationship between the Hawking–Hayward quasi-local mass and the Hubble function is fulfilled. In this manner, we can study the role played by the large-scale physics (cosmic evolution) on the local scale physics (evolution of a black hole).
Neutrino currents in wakes of cosmic strings
Authors: Sau Sovan , Sanyal Soma
Published: February 2020

Neutrinos rotating around Abelian Higgs strings will generate a neutral current close to the string. As the string moves through the cosmic plasma, the velocity kick generated by the motion of the string will enhance the neutrino current in the wake region. The neutrino current density depends on its distance from the string and is oscillatory in nature. This leads to neutrino density gradients in the plasma. Such a flux of neutrinos with periodic density fluctuations will lead to electron currents in the plasma. The current will act like a cross-perturbation across the cosmic string wake. The perturbation as well as the high Reynolds number of the plasma will result in the generation of magnetic fields in the wake of the cosmic string.
A Monte Carlo calculation of the secondary electron emission in the backward direction from a SiO2 macro-capillary
Authors: Li Chao , Tőkési Károly , Repetto Luca , Xiao Liye , Liu Junbiao , Gao Zhaoshun , Han Li , Da Bo , Bereczky Réka Judit , Ding Zejun
Published: February 2020

A Monte Carlo calculation of the secondary electron emission from a SiO2 macro-capillary in the backward direction induced by electron irradiation is presented with the aim to understand transmission guiding of a scanning electron beam through a borosilicate glass macro-capillary. The theoretical modeling of electron transport in SiO2 capillary incorporates the elastic, inelastic and phonon scatterings, resulting, respectively, from the interactions with nucleus, electrons and phonons. The influence on electron inelastic scattering by the insulator bandgap is also considered. In this work a simplified approach has been employed to deal with the charging of the internal wall of the capillary and it is found that at a glancing incident angle, the secondary electrons are mostly originated from the top surface.

Graphical abstract
Pre-Evaluating the Technical Efficiency Gains from Potential Mergers and Acquisitions in the IC Design Industry
Authors: Li Ying , Chiu Yung-Ho , Lin Tai-Yu , Chang Tzu-Han
Published: February 2020

Increased global competition has led to a slowdown in Taiwan’s domestic semiconductor industry growth, which has resulted in many semiconductor companies reducing their investments and or seeking mergers and acquisitions (M & As) to increase market power, expand their business territories or increase their competitive edge. However, as there is general uncertainty regarding the efficiencies to be gained from these M & As, there has been an increase in M & A supervision. While past research has explored company operations and management efficiency after mergers, there has been less focus on potential mergers. Therefore, this study used a resample slacks-based measure (RSBM) and merger potential gains models to evaluate potential merger efficiency gains. Data on 29 Taiwanese-listed integrated circuit (IC) design industry firms were collected to evaluate the efficiency of potential M & As, from which it was found that the potential M & As efficiencies had positive and negative values, indicating that efficiency gains were not guaranteed. A positive value was found for a potential M & A between MTK & NOVATEK and MTK & DAVICOM, which meant that a potential M & A would increase operating efficiencies and reduce costs.
Cloud Computing-Based Socially Important Locations Discovery on Social Media Big Datasets
Authors: Dokuz Ahmet Sakir , Celik Mete
Published: February 2020

Socially important locations are places which are frequently visited by social media users in their social media lifetime. Discovering socially important locations provides valuable information, such as which locations are frequently visited by a social media user, which locations are common for a social media user group, and which locations are socially important for a group of urban area residents. However, discovering socially important locations is challenging due to huge volume, velocity, and variety of social media datasets, inefficiency of current interest measures and algorithms on social media big datasets, and the need of massive spatial and temporal calculations for spatial social media analyses. In contrast, cloud computing provides infrastructure and platforms to scale compute-intensive jobs. In the literature, limited number of studies related to socially important locations discovery takes into account cloud computing systems to scale increasing dataset size and to handle massive calculations. This study proposes a cloud-based socially important locations discovery algorithm of Cloud SS-ILM to handle volume and variety of social media big datasets. In particular, in this study, we used Apache Hadoop framework and Hadoop MapReduce programming model to scale dataset size and handle massive spatial and temporal calculations. The performance evaluation of the proposed algorithm is conducted on a cloud computing environment using Turkey Twitter social media big dataset. The experimental results show that using cloud computing systems for socially important locations discovery provide much faster discovery of results than classical algorithms. Moreover, the results show that it is necessary to use cloud computing systems for analyzing social media big datasets that could not be handled with traditional stand-alone computer systems. The proposed Cloud SS-ILM algorithm could be applied on many application areas, such as targeted advertisement of businesses, social media utilization of cities for city planners and local governments, and handling emergency situations.
Continuous variable quantum perceptron
Authors: Benatti F. , Mancini S. , Mangini S.
Published: February 2020

We present a model of Continuous Variable Quantum Perceptron (CVQP), also referred to as neuron in the following, whose architecture implements a classical perceptron. The necessary nonlinearity is obtained via measuring the output qubit and using the measurement outcome as input to an activation function. The latter is chosen to be the so-called Rectified linear unit (ReLu) activation function by virtue of its practical feasibility and the advantages it provides in learning tasks. The encoding of classical data into realistic finitely squeezed states and the use of superposed (entangled) input states for specific binary problems are discussed.
Nonrelativistic treatment of hydrogen-like and neutral atoms subjected to the generalized perturbed Yukawa potential with centrifugal barrier in the symmetries of noncommutative quantum mechanics
Authors: Maireche Abdelmadjid
Published: February 2020

We have obtained the approximate analytical solutions of the nonrelativistic Hydrogen-like atoms such as [Formula: see text] and [Formula: see text] and neutral atoms such as ([Formula: see text] and [Formula: see text]) atoms with a newly proposed generalized perturbed Yukawa potential with centrifugal barrier (GPYPCB) model using the generalized Bopp’s shift method and standard perturbation theory in the symmetries of noncommutative three-dimensional real space phase (NC: 3D-RSP). By approximating the centrifugal term through the Greene–Aldrich approximation scheme, we have obtained the energy eigenvalues and generalized Hamiltonian operator for all orbital quantum numbers [Formula: see text] in the symmetries of NC: 3D-RSP. The potential is a superposition of the perturbed Yukawa potential and new terms proportional with [Formula: see text]) appear as a result of the effects of noncommutativity properties of space and phase on the perturbed Yukawa potential model. The obtained energy eigenvalues appear as functions of the generalized Gamma function, the discreet atomic quantum numbers [Formula: see text], two infinitesimal parameters [Formula: see text], which are induced by (position–position and phase–phase). In addition, the dimensional parameters [Formula: see text] of perturbed Yukawa potential with centrifugal barrier model in NC: 3D-RSP. Furthermore, we have shown that the corresponding Hamiltonian operator in (NC: 3D-RSP) symmetries is the sum of the Hamiltonian operator of perturbed Yukawa potential model and the two operators are modified spin–orbit interaction and the modified Zeeman operator for the previous Hydrogenic and neutral atoms.
New classes of projectively related Finsler metrics of constant flag curvature
Authors: Creţu Georgeta
Published: February 2020

We define a Weyl-type curvature tensor of [Formula: see text]-type to provide a characterization for Finsler metrics of constant flag curvature. This Weyl-type curvature tensor is projective invariant only to projective factors that are Hamel functions. Based on this aspect, we construct new families of projectively related Finsler metrics that have constant flag curvature.
Pilot study on comparisons between the effectiveness of mobile video-guided and paper-based home exercise programs on improving exercise adherence, self-efficacy for exercise and functional outcomes of patients with stroke with 3-month follow-up: A single-blind randomized controlled trial
Authors: Chung Bryan Ping Ho , Chiang Wendy Kam Ha , Lau Herman , Lau Titanic Fuk On , Lai Charles Wai Kin , Sit Claudia Sin Yi , Chan Ka Yan , Yeung Chau Yee , Lo Tak Man , Hui Elsie , Lee Jenny Shun Wah
Published: February 2020

Objective: To compare the effectiveness of mobile video-guided home exercise program and standard paper-based home exercise program.

Methods: Eligible participants were randomly assigned to either experimental group with mobile video-guided home exercise program or control group with home exercise program in a standard pamphlet for three months. The primary outcome was exercise adherence. The secondary outcomes were self-efficacy for exercise by Self-Efficacy for Exercise (SEE) Scale; and functional outcomes including mobility level by Modified Functional Ambulatory Category (MFAC) and basic activities of daily living (ADL) by Modified Barthel Index (MBI). All outcomes were captured by phone interviews at 1 day, 1 month and 3 months after the participants were discharged from the hospitals.

Results: A total of 56 participants were allocated to the experimental group [Formula: see text] and control group [Formula: see text]. There were a significant between-group differences in 3-months exercise adherence (experimental group: 75.6%; control group: 55.2%); significant between-group differences in 1-month SEE (experimental group: 58.4; control group: 43.3) and 3-month SEE (experimental group: 62.2; control group: 45.6). For functional outcomes, there were significant between-group differences in 3-month MFAC gain (experimental group: 1.7; control group: 1.0). There were no between-group differences in MBI gain.

Conclusion: The use of mobile video-guided home exercise program was superior to standard paper-based home exercise program in exercise adherence, SEE and mobility gain but not basic ADL gain for patients recovering from stroke.
Size-Dependent Hygro-Thermal Buckling of Porous FGM Sandwich Microplates and Microbeams Using a Novel Four-Variable Shear Deformation Theory
Authors: Sobhy Mohammed
Published: February 2020

Based on a new shear deformation theory and the modified couple stress theory, in this paper, the hygro-thermal buckling of porous FGM sandwich microplates and microbeams is investigated. Unlike the classical elasticity theory, the present model involves a material length scale parameter, and, thereby, can capture the small size effect. The four-variable shear deformation theory with a new shape function is utilized to derive the governing stability equations for the microplates and microbeams from the principle of virtual work. The present microstructures are composed of three layers and subjected to hygro-thermal conditions. The core is assumed to be fully homogeneous and isotropic material. While, the face layers are made from porous functionally graded materials that vary only in the thickness direction. The governing equations are solved analytically to obtain the thermal buckling of FGM sandwich microplates and microbeams under humidity effects. The temperature rise and moisture concentration are graded uniformly, linearly or nonlinearly through the thickness. Comparison studies are made between the present results and those available in the literature to check the validity of the obtained formulations and results. Moreover, the effects played by the length scale parameter, power-law exponent, moisture concentration, core thickness and other parameters on the thermal buckling of microplates and microbeams are all investigated.
Anti-Plane Wave in a Piezoelectric Viscoelastic Composite Medium: A Semi-Analytical Finite Element Approach Using PML
Authors: Chaki Mriganka Shekhar , Singh Abhishek Kumar
Published: February 2020

In the present study, anti-plane wave propagation has been considered in a piezoelectric viscoelastic composite medium where the surface has been coated with an infinitesimally thin and perfectly conducting electrode which is grounded. The frequency equation has been obtained analytically and the result has been found in well agreement with the classical B-G wave frequency equation which validates the result. Moreover, Semi-Analytical Finite Element using Perfectly Matched Layer (SAFE-PML) method has been adopted in order to deduce frequency equation. Numerical computation and graphical illustration have been done in order to study some influencing parameters. Both frequency equations obtained through analytical method and SAFE-PML method have been compared through graphs which also validate the obtained results.
Modeling of Temperature-Dependent Hardness for Pure FCC and HCP Metals
Authors: Xu Niandong , Li Weiguo , Ma Jianzuo , Deng Yong , Kou Haibo , Li Ying , Yang Mengqing , Zhang Xuyao , Zhang Xin
Published: February 2020

In this study, a theoretical model is developed to characterize the quantitative effect of temperature on the hardness of pure FCC and HCP metals. The model is verified by comparison with the available experimental results of Cu, Al, Zn, Mg, Be, Zr, Ni, Ir, Rh, and Ti at different temperatures. Compared with the widely quoted Westbrook model and Ito–Shishokin model which need piecewise fitting to describe experimental values, the present model merely needs two hardness values at different temperatures to predict the experimental results, reducing reliance on conducting lots of experiments. This work provides a convenient method to predict temperature-dependent hardness of pure metals, and it is worth noting that it can be applied to a wide temperature range from absolute zero to melting point.
On a conjecture of Lemmermeyer
Authors: Aouissi Siham , Talbi Mohamed , Ismaili Moulay Chrif , Azizi Abdelmalek
Published: February 2020

Let [Formula: see text] be a prime and denote by [Formula: see text] a primitive third root of unity. Recently, Lemmermeyer presented a conjecture about [Formula: see text]-class groups of pure cubic fields [Formula: see text] and of their normal closures [Formula: see text]. The main goal of this paper is to reduce Lemmermeyer’s conjecture to a problem of unit theory by showing that the conjecture of Lemmermeyer follows from Conjecture 2.9.
Epipelagic Langlands parameters and L-packets for unitary groups
Authors: Feng Tony , Ronchetti Niccolò , Tsai Cheng-Chiang
Published: February 2020

Reeder and Yu have recently given a new construction of a class of supercuspidal representations called epipelagic representations [M. Reeder and J.-K. Yu, Epipelagic representations and invariant theory, J. Amer. Math. Soc. 27(2) (2014) 437–477, MR 3164986]. We explicitly calculate the Local Langlands Correspondence for certain families of epipelagic representations of unitary groups, following the general construction of Kaletha [Epipelagic [Formula: see text]-packets and rectifying characters, Invent. Math. 202(1) (2015) 1–89, MR 3402796]. The interesting feature of our computation is that we find simplifications within [Formula: see text]-packets of the two novel invariants introduced in the above-mentioned paper of Kaletha, the toral invariant and the admissible L-embedding.
Positive-definite ternary quadratic forms with the same representations over ℤ
Authors: Oishi-Tomiyasu Ryoko
Published: February 2020

Kaplansky conjectured that if two positive-definite ternary quadratic forms have perfectly identical representations over [Formula: see text], they are equivalent over [Formula: see text] or constant multiples of regular forms, or is included in either of two families parameterized by [Formula: see text]. Our results aim to clarify the limitations imposed to such a pair by computational and theoretical approaches. First, the result of an exhaustive search for such pairs of integral quadratic forms is presented in order to provide a concrete version of the Kaplansky conjecture. The obtained list contains a small number of non-regular forms that were confirmed to have the identical representations up to 3,000,000 by computation. However, a strong limitation on the existence of such pairs is still observed, regardless of whether the coefficient field is [Formula: see text] or [Formula: see text]. Second, we prove that if two pairs of ternary quadratic forms have the identical simultaneous representations over [Formula: see text], their constant multiples are equivalent over [Formula: see text]. This was motivated by the question why the other families were not detected in the search. In the proof, the parametrization of quartic rings and their resolvent rings by Bhargava is used to discuss pairs of ternary quadratic forms.
The number of edges in power graph of finite groups
Authors: Jafari S. H.
Published: February 2020

Let [Formula: see text] be a finite groups. The power graph of [Formula: see text] is a graph with vertex set [Formula: see text] and two distinct element [Formula: see text] are adjacent if one of them is power another. We give a short elementary proof for [Formula: see text] has a maximum number edges in all groups of order [Formula: see text].
Linking Focusing and Resolution with Selection
Authors: Burel Guillaume
Published: February 2020

Focusing and selection are techniques that shrink the proof-search space for respectively sequent calculi and resolution. To bring out a link between them, we generalize them both: we introduce a sequent calculus where each
occurrence
of an atomic formula can have a positive or a negative polarity; and a resolution method where each literal, whatever its sign, can be selected in input clauses. We prove the equivalence between cut-free proofs in this sequent calculus and derivations of the empty clause in that resolution method. Such a generalization is not semi-complete in general, which allows us to consider complete instances that correspond to theories of any logical strength. We present three complete instances: first, our framework allows us to show that ordinary focusing corresponds to hyperresolution and semantic resolution; the second instance is deduction modulo theory and the related framework called superdeduction; and a new setting, not captured by any existing framework, extends deduction modulo theory with rewriting rules having several left-hand sides, which restricts even more the proof-search space.
Starch: A Flexible, Adaptable Carbon Store Coupled to Plant Growth
Authors: Smith Alison M. , Zeeman Samuel C.
Published: February 2020

Research in the past decade has uncovered new and surprising information about the pathways of starch synthesis and degradation. This includes the discovery of previously unsuspected protein families required both for processes and for the long-sought mechanism of initiation of starch granules. There is also growing recognition of the central role of leaf starch turnover in making carbon available for growth across the day-night cycle. Sophisticated systems-level control mechanisms involving the circadian clock set rates of nighttime starch mobilization that maintain a steady supply of carbon until dawn and modulate partitioning of photosynthate into starch in the light, optimizing the fraction of assimilated carbon that can be used for growth. These discoveries also uncover complexities: Results from experiments with Arabidopsis leaves in conventional controlled environments are not necessarily applicable to other organs or species or to growth in natural, fluctuating environments.
Mitochondrial Proteases: Multifaceted Regulators of Mitochondrial Plasticity
Authors: Deshwal Soni , Fiedler Kai Uwe , Langer Thomas
Published: February 2020

Mitochondria are essential metabolic hubs that dynamically adapt to physiological demands. More than 40 proteases residing in different compartments of mitochondria, termed mitoproteases, preserve mitochondrial proteostasis and are emerging as central regulators of mitochondrial plasticity. These multifaceted enzymes limit the accumulation of short-lived, regulatory proteins within mitochondria, modulate the activity of mitochondrial proteins by protein processing, and mediate the degradation of damaged proteins. Various signaling cascades coordinate the activity of mitoproteases to preserve mitochondrial homeostasis and ensure cell survival. Loss of mitoproteases severely impairs the functional integrity of mitochondria, is associated with aging, and causes pleiotropic diseases. Understanding the dual function of mitoproteases as regulatory and quality control enzymes will help unravel the role of mitochondrial plasticity in aging and disease.
Calcium Signaling in the Oligodendrocyte Lineage: Regulators and Consequences
Authors: Paez Pablo M. , Lyons David A.
Published: February 2020

Cells of the oligodendrocyte lineage express a wide range of Ca2+ channels and receptors that regulate oligodendrocyte progenitor cell (OPC) and oligodendrocyte formation and function. Here we define those key channels and receptors that regulate Ca2+ signaling and OPC development and myelination. We then discuss how the regulation of intracellular Ca2+ in turn affects OPC and oligodendrocyte biology in the healthy nervous system and under pathological conditions. Activation of Ca2+ channels and receptors in OPCs and oligodendrocytes by neurotransmitters converges on regulating intracellular Ca2+, making Ca2+ signaling a central candidate mediator of activity-driven myelination. Indeed, recent evidence indicates that localized changes in Ca2+ in oligodendrocytes can regulate the formation and remodeling of myelin sheaths and perhaps additional functions of oligodendrocytes and OPCs. Thus, decoding how OPCs and myelinating oligodendrocytes integrate and process Ca2+ signals will be important to fully understand central nervous system formation, health, and function.
Mapping Structural Dynamics of Proteins with Femtosecond Stimulated Raman Spectroscopy
Authors: Fang Chong , Tang Longteng
Published: February 2020

The structure–function relationships of biomolecules have captured the interest and imagination of the scientific community and general public since the field of structural biology emerged to enable the molecular understanding of life processes. Proteins that play numerous functional roles in cellular processes have remained in the forefront of research, inspiring new characterization techniques. In this review, we present key theoretical concepts and recent experimental strategies using femtosecond stimulated Raman spectroscopy (FSRS) to map the structural dynamics of proteins, highlighting the flexible chromophores on ultrafast timescales. In particular, wavelength-tunable FSRS exploits dynamic resonance conditions to track transient-species-dependent vibrational motions, enabling rational design to alter functions. Various ways of capturing excited-state chromophore structural snapshots in the time and/or frequency domains are discussed. Continuous development of experimental methodologies, synergistic correlation with theoretical modeling, and the expansion to other nonequilibrium, photoswitchable, and controllable protein systems will greatly advance the chemical, physical, and biological sciences.
Facile Synthesis of an Efficient Ni–Fe–Co Based Oxygen Evolution Reaction Electrocatalyst
Authors: Lindstrom Mary Lou , Gakhar Ruchi , Raja Krishna , Chidambaram Dev
Published: February 2020

Electrolytic water splitting offers energy storage and conversion opportunities, yet the slow kinetics of the oxygen evolution reaction requires the incorporation of catalytic materials. Herein, we present a facile method for the synthesis of a low-cost Ni-Fe-Co material that efficiently catalyzes the oxygen evolution reaction. A mixed transition metal electrocatalyst was synthesized using a nickel-plated iron substrate and a low concentration cobalt reagent. The catalyst was able to achieve competitive current densities (>130 mA cm−2) and still exhibit a low overpotential of 0.30 V at the benchmark current density of 10 mA cm−2. The Ni-Fe-Co catalyst was stable and maintained its activity during 24 h of electrolysis in alkaline media. The catalyst was also stable when maintained in ambient conditions for 90 days. This is the first reported oxygen evolution reaction catalyst that exhibits these competitive characteristics and that was synthesized using an environmentally-conscious, one-step process that can be manufactured on an industrial scale.
Perspective—Reversible Magnesium Storage in Silicon: An Ongoing Challenge
Authors: Zhang Dongyang , Fu Jintao , Wang Zeyu , Wang Lin , Corsi John S. , Detsi Eric
Published: February 2020

The increasing popularity of rechargeable commercial lithium-ion batteries raises a serious sustainability concern: Relying solely on lithium-ion batteries for the global portable/non-stationary electrochemical energy storage demands will put considerable strain on the resources used in these batteries. Therefore, alternative rechargeable battery technologies, including magnesium-ion batteries, are desirable. Silicon is very attractive for largescale application as a magnesium-ion battery anode due to its high natural abundance and its ultrahigh gravimetric capacity of 3,816 mAh g−1 for magnesium storage in the form of magnesium silicide (Mg2Si). Despite these unique advantages, to date the reversible electrochemical storage of magnesium in silicon has not yet been demonstrated experimentally, although theoretical studies predict that alloying reactions of silicon with magnesium are thermodynamically possible. The present article is aimed at elucidating the challenge and current status associated with the reversible storage of magnesium in silicon and presenting the future needs to overcome this challenge.
Corrosion Testing of Anodized Aerospace Alloys: Comparison Between Immersion and Salt Spray Testing using Electrochemical Impedance Spectroscopy
Authors: Usman B. J. , Scenini F. , Curioni M.
Published: February 2020

The corrosion performance provided by two anodizing treatments aiming at obtaining films with comparable thickness but different pore morphology was evaluated by immersion, salt spray, and a hybrid tests. The hybrid test was performed in cycles by alternating between immersion and salt spray tests. The corrosion progression was evaluated at selected times by electrochemical impedance spectroscopy (EIS). The EIS indicated that, during immersion test, the self-sealing of the pores due to the precipitation of aluminium hydroxide was favored, and it provided a substantial contribution to the improved corrosion resistance. Vice versa, during salt spray testing, the continuous flow of electrolyte promoted aluminium oxide film dissolution. The EIS study was complemented by the surface appearance and composition of specimens before and after exposure using Field Emission-Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analysis. Overall, the relative performance of the anodic oxides was shown to be dependent on the exposure conditions. In fact, an anodic film with finer pores behaved better during immersion tests, whereas films with coarser pores provided better corrosion protection during salt spray testing.
Understanding the Aqueous Solubility of Anthraquinone Sulfonate Salts: The Quest for High Capacity Electrolytes of Redox Flow Batteries
Authors: Mao Jiatao , Ruan Wenqing , Chen Qing
Published: February 2020

Charge storage in concentrated electrolytes gives redox flow batteries (RFBs) a unique edge in grid-scale energy storage. It also creates a unique challenge in the design of organic molecules as alternatives to expensive vanadium salts. Molecules often come in the form of organic salts, and dissolve by ionic bond breakingand ion solvation, which can hardly be interpreted by “like dissolves like.” Here we use anthraquinone sulfonate salts as a model system to investigate factors underlying their aqueous solubility. We synthesize fifteen salts, measure their solubilities with UV–vis spectroscopy, and find that the solubility of the same quinone could change by three orders of magnitude with a change in its counter-cation. The same impact can come from the position and number of the sulfonate groups. We explain the results with the differences in the ion solvation energy and the lattice energy, the latter of which is corroborated by single-crystal X-ray diffraction. We also derive a simple method to semi-quantitatively predict the solubility of a quinone sulfonate salt based on that of a common sulfate salt. The work provides a physical-chemical base for understanding the solubilities of organic salts for the design of high capacity electrolytes for aqueous flow batteries.
Can whole body vibration exercises promote improvement on quality of life and on chronic pain level of metabolic syndrome patients? A pseudorandomized crossover study
Authors: Paineiras-Domingos Laisa Liane , Sá-Caputo Danúbia da Cunha , Francisca-Santos Arlete , Reis-Silva Aline , Carvalho-Lima Rafaelle Pacheco , Neves Mario Fritsch T. , Xavier Vinicius Layter , Quinart Hervé , Boyer François Constant , Sartorio Alessandro , Taiar Redha , Bernardo-Filho Mario
Published: February 2020

Quality of life (QoL) is one of the most important health outcome concepts expressed subjectively. Chronic pain (CP) is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Taking into account the poor QoL and the CP already described in metabolic syndrome (MSy) individuals, this study aimed to evaluate the effects of whole body vibration exercises (WBVE) on these parameters in this population. Thirty-three MSy patients were divided in subgroups A [whole body vibration exercise group (WBVeG), n = 17, 15 females/2 males, 61.1 ± 8.4 yr] and B (control group, n = 16, 14 females/2 males, 58.2 ± 9.1 yr). Subgroup A performed 10 sessions (2 times/wk) of WBVE (18 min/session, with a frequency from 5 up to 14 Hz and a peak-to-peak displacement of 2.5, 5.0, and 7.5 mm) on a side-alternating vibrating platform (VP). Subgroup B did the same protocol, but the VP was turned off. The individuals answered the World Health Organization Quality of Life bref (WHOQoL-bref) questionnaire before the first and after the 10th session. The chronic pain level (CPL) was measured by a numeric rating scale (0–10) before and at the end of each session. Significant improvements were found in physical health ( P = 0.05) and psychological health ( P = 0.04) domains of WHOQoL-bref in WBVeG. A significant acute reduction of the CPL was found in the WBVeG after the protocol, considering the first session and at the last session. WBVE marginally improved physical health and psychological health and decrease the CPL in acute interventions.

NEW & NOTEWORTHY Metabolic syndrome patients experience poor quality of life, frequently associated with lack of exercise and bad dietary habits. Additionally, factors such as obesity, neuromusculoskeletal impairment, and peripheral endothelial dysfunction result in a chronic pain level. Whole body vibration exercise might represent a suitable physical therapy, since it is easy to perform, low cost, safe, and capable of promoting an improvement of quality of life and reducing chronic pain level during acute interventions in metabolic syndrome individuals.
Joint and muscle-tendon coordination strategies during submaximal jumping
Authors: Wade Logan , Lichtwark Glen A. , Farris Dominic J.
Published: February 2020

Previous research has demonstrated that during submaximal jumping humans prioritize reducing energy consumption by minimizing countermovement depth. However, sometimes movement is constrained to a nonpreferred pattern, and this requires adaptation of neural control that accounts for complex interactions between muscle architecture, muscle properties, and task demands. This study compared submaximal jumping with either a preferred or a deep countermovement depth to examine how joint and muscle mechanics are integrated into the adaptation of coordination strategies in the deep condition. Three-dimensional motion capture, two force plates, electromyography, and ultrasonography were used to examine changes in joint kinetics and kinematics, muscle activation, and muscle kinematics for the lateral gastrocnemius and soleus. Results demonstrated that a decrease in ankle joint work during the deep countermovement depth was due to increased knee flexion, leading to unfavorably short biarticular muscle lengths and reduced active fascicle length change during ankle plantar flexion. Therefore, ankle joint work was likely decreased because of reduced active fascicle length change and operating position on the force-length relationship. Hip joint work was significantly increased as a result of altered muscle activation strategies, likely due to a substantially greater hip extensor muscle activation period compared with plantar flexor muscles during jumping. Therefore, coordination strategies at individual joints are likely influenced by time availability, where a short plantar flexor activation time results in dependence on muscle properties, instead of simply altering muscle activation, while the longer time for contraction of muscles at the hip allows for adjustments to voluntary neural control.

NEW & NOTEWORTHY Using human jumping as a model, we show that adapting movement patterns to altered task demands is achieved differently by muscles across the leg. Because of proximal-to-distal sequencing, distal muscles (i.e., plantar flexors) have reduced activation periods and, as a result, rely on muscle contractile properties (force-length relationship) for adjusting joint kinetics. For proximal muscles that have greater time availability, voluntary activation is modulated to adjust muscle outputs.
High-intensity muscle contraction-mediated increases in Akt1 and Akt2 phosphorylation do not contribute to mTORC1 activation and muscle protein synthesis
Authors: Maruyama Yuki , Ikeda Chisaki , Wakabayashi Koki , Ato Satoru , Ogasawara Riki
Published: February 2020

High-intensity muscle contraction (HiMC) is known to induce muscle protein synthesis, a process in which mechanistic target of rapamycin (mTOR) is reported to play a critical role. However, the mechanistic details have not been completely elucidated. Here, we investigated whether Akt plays a role in regulating HiMC-induced mTORC1 activation and muscle protein synthesis using a rodent model of resistance exercise and MK2206 (an Akt kinase inhibitor). The right gastrocnemius muscle of male C57BL/6J mice aged 10 wk was isometrically contracted via percutaneous electrical stimulation (100 Hz, 5 sets of 10 3-s contractions, 7-s rest between contractions, and 3-min rest between sets), while the left gastrocnemius muscle served as a control. Vehicle or MK2206 was injected intraperitoneally 6 h before contraction. MK2206 inhibited both resting and HiMC-induced phosphorylation of Akt1 Ser-473 and Akt2 Ser-474. MK2206 also inhibited the resting phosphorylation of p70S6K and 4E-BP1, which are downstream targets of mTORC1; however, it did not inhibit the HiMC-induced increase in phosphorylation of these targets. Similarly, MK2206 inhibited the resting muscle protein synthesis, but not the resistance exercise-induced muscle protein synthesis. On the basis of these observations, we conclude that although Akt2 regulates resting mTORC1 activity and muscle protein synthesis, HiMC-induced increases in mTORC1 activity and muscle protein synthesis are Akt-independent processes.

NEW & NOTEWORTHY Akt is well known to be an upstream regulator of mechanistic target of rapamycin (mTOR) and has three isoforms in mammals, namely, Akt1, Akt2, and Akt3. We found that high-intensity muscle contraction (HiMC) increases Akt1 and Akt2 phosphorylation; however, HiMC-induced increases in mTORC1 activity and muscle protein synthesis are Akt-independent processes.
Both hyperthermia and dehydration during physical work in the heat contribute to the risk of acute kidney injury
Authors: Chapman Christopher L. , Johnson Blair D. , Vargas Nicole T. , Hostler David , Parker Mark D. , Schlader Zachary J.
Published: February 2020

Occupational heat stress increases the risk of acute kidney injury (AKI) and kidney disease. This study tested the hypothesis that attenuating the magnitude of hyperthermia (i.e., increase in core temperature) and/or dehydration during prolonged physical work in the heat attenuates increases in AKI biomarkers. Thirteen healthy adults (3 women, 23 ± 2 yr) exercised for 2 h in a 39.7 ± 0.6°C, 32 ± 3% relative-humidity environmental chamber. In four trials, subjects received water to remain euhydrated ( Water), continuous upper-body cooling ( Cooling), a combination of both ( Water + Cooling), or no intervention ( Control). The magnitude of hyperthermia (increased core temperature of 1.9 ± 0.3°C; P < 0.01) and dehydration (percent loss of body mass of −2.4 ± 0.5%; P < 0.01) were greatest in the Control group. There were greater increases in the urinary biomarkers of AKI in the Control trial: albumin (increase of 13 ± 11 μg/mL; P ≤ 0.05 compared with other trials), neutrophil gelatinase-associated lipocalin (NGAL) (increase of 16 ± 14 ng/dL, P ≤ 0.05 compared with Cooling and Water + Cooling groups), and insulin-like growth factor-binding protein 7 (IGFBP7) (increase of 227 ± 190 ng/mL; P ≤ 0.05 compared with other trials). Increases in IGFBP7 in the Control trial persisted after correcting for urine production/concentration. There were no differences in the AKI biomarker tissue inhibitor of metalloproteinase 2 (TIMP-2) between trials ( P ≥ 0.11). Our findings indicate that the risk of AKI is highest with greater magnitudes of hyperthermia and dehydration during physical work in the heat. Additionally, the differential findings between IGFBP7 (preferentially secreted in proximal tubules) and TIMP-2 (distal tubules) suggest the proximal tubules as the location of potential renal injury.

NEW & NOTEWORTHY We demonstrate that the risk for acute kidney injury (AKI) is higher in humans with greater magnitudes of hyperthermia and dehydration during physical work in the heat and that alleviating the hyperthermia and/or limiting dehydration equally reduce the risk of AKI. The biomarker panel employed in this study suggests the proximal tubules as the location of potential renal injury.