bluuebunny/crossref_metadata_2025_split huggingface dataset:
Making of water soluble curcumin to potentiate conventional antimicrobials by inducing apoptosis-like phenomena among drug-resistant bacteria
Authors: Yadav Shivangi , Singh Ashish Kumar , Agrahari Anand Kumar , Sharma Kavyanjali , Singh Anoop Shyam , Gupta Munesh Kumar , Tiwari Vinod Kumar , Prakash Pradyot 
Published: August 2020

AbstractThe upsurge of multidrug resistant bacterial infections with declining pipeline of newer antibiotics has made it imperative to develop newer molecules or tailor the existing molecules for more effective antimicrobial therapies. Since antiquity, the use of curcumin, in the form ofCurcuma longapaste, to treat infectious lesions is unperturbed despite its grave limitations like instability and aqueous insolubility. Here, we utilized “click” chemistry to address both the issues along with improvisation of its antibacterial and antibiofilm profile. We show that soluble curcumin disrupts several bacterial cellular processes leading to the Fenton’s chemistry mediated increased production of reactive oxygen species and increased membrane permeability of both Gram-positive and Gram-negative bacteria. We here report that its ability to induce oxidative stress can be harnessed to potentiate activities of ciprofloxacin, meropenem, and vancomycin. In addition, we demonstrated that the soluble curcumin reported herein even sensitizes resistant Gram-negative clinical isolates to the Gram-positive specific antibiotic vancomycin, thereby expanding the antibacterial spectrum of this drug. This work shows that the soluble curcumin can be used to enhance the action of existing antimicrobials against both Gram-positive and Gram-negative bacteria thus strengthening the antibiotic arsenal for fighting resistant bacterial infections for many years to come.
Training induced fatigability assessed by sEMG in Pre-Olympic ice-skaters
Authors: Pakosz Paweł , Konieczny Mariusz 
Published: August 2020

AbstractThe aim of this study was to investigate the size of the change and asymmetry in fatigability of gluteus maximus muscles during endurance training in short-track. The research has taken into account the position of athletes during skating and the problem of fatigue and pain in these muscles. The research covered involved eight female athletes of the Polish National Team in short track, which had been prepared to the Olympic Games in PyeongChang. The surface electromyography (sEMG) system was used to measure fatigue of right and left gluteus maximus muscles, in the modified Biering–Sorensen test. The test was conducted five times during the training: before training, after warmup, and after each of 3 series of the endurance training. Comparing the mean frequency of the surface electromyography power spectrum of the test, statistically significant reduction of the average frequency value of the right muscle from 55.61 ± 7.08 to 48.64 ± 4.48 Hz and left muscle from 58.78 ± 4.98 to 53.18 ± 4.62 Hz was reported, which prove the muscle fatigue. In subsequent series tests, the sEMG signal frequency of begin decrease more than the end of the each measurement, which determines the fatigue threshold. The size of the d Cohen effect in fatigue drops along with subsequent five tests during the training. Skaters has higher frequency reduction of the right lower limb, which indicates its greater fatigue during skateing. The fatigue and asymmetry in muscle observed in short-track has implications for training and performance.
Towards applying NMR relaxometry as a diagnostic tool for bone and soft tissue sarcomas: a pilot study
Authors: Masiewicz Elzbieta , Ashcroft George P. , Boddie David , Dundas Sinclair R. , Kruk Danuta , Broche Lionel M. 
Published: August 2020

AbstractThis work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients. We present the results of an ex vivo pilot study involving 10 cases of biopsy-proven sarcoma and we propose a quantitative method to analyse 1H NMR relaxation dispersion profiles based on a model-free approach describing the main dynamical processes in the tissues and assessing the amplitude of the Quadrupole Relaxation Enhancement effects due to 14N. This approach showed five distinct groups of dispersion profiles indicating five discrete categories of sarcoma, with differences attributable to microstructure and rigidity. Data from tissues surrounding sarcomas indicated very significant variations with the proximity to tumour, which may be attributed to varying water content but also to tissue remodelling processes due to the sarcoma. This pilot study illustrates the potential of FFC relaxometry for the detection and characterisation of sarcoma.
Improved locomotor recovery after contusive spinal cord injury in Bmal1−/− mice is associated with protection of the blood spinal cord barrier
Authors: Slomnicki Lukasz P. , Myers Scott A. , Saraswat Ohri Sujata , Parsh Molly V. , Andres Kariena R. , Chariker Julia H. , Rouchka Eric C. , Whittemore Scott R. , Hetman Michal 
Published: August 2020

AbstractThe transcription factor BMAL1/ARNTL is a non-redundant component of the clock pathway that regulates circadian oscillations of gene expression. Loss of BMAL1 perturbs organismal homeostasis and usually exacerbates pathological responses to many types of insults by enhancing oxidative stress and inflammation. Surprisingly, we observed improved locomotor recovery and spinal cord white matter sparing in Bmal1−/− mice after T9 contusive spinal cord injury (SCI). While acute loss of neurons and oligodendrocytes was unaffected, Bmal1 deficiency reduced the chronic loss of oligodendrocytes at the injury epicenter 6 weeks post SCI. At 3 days post-injury (dpi), decreased expression of genes associated with cell proliferation, neuroinflammation and disruption of the blood spinal cord barrier (BSCB) was also observed. Moreover, intraspinal extravasation of fibrinogen and immunoglobulins was decreased acutely at dpi 1 and subacutely at dpi 7. Subacute decrease of hemoglobin deposition was also observed. Finally, subacutely reduced levels of the leukocyte marker CD45 and even greater reduction of the pro-inflammatory macrophage receptor CD36 suggest not only lower numbers of those cells but also their reduced inflammatory potential. These data indicate that Bmal1 deficiency improves SCI outcome, in part by reducing BSCB disruption and hemorrhage decreasing cytotoxic neuroinflammation and attenuating the chronic loss of oligodendrocytes.
Using nuclear envelope mutations to explore age-related skeletal muscle weakness
Authors: Battey Edmund , Stroud Matthew J. , Ochala Julien 
Published: August 2020

Abstract
Skeletal muscle weakness is an important determinant of age-related declines in independence and quality of life but its causes remain unclear. Accelerated ageing syndromes such as Hutchinson–Gilford Progerin Syndrome, caused by mutations in genes encoding nuclear envelope proteins, have been extensively studied to aid our understanding of the normal biological ageing process. Like several other pathologies associated with genetic defects to nuclear envelope proteins including Emery–Dreifuss muscular dystrophy, Limb–Girdle muscular dystrophy and congenital muscular dystrophy, these disorders can lead to severe muscle dysfunction. Here, we first describe the structure and function of nuclear envelope proteins, and then review the mechanisms by which mutations in genes encoding nuclear envelope proteins induce premature ageing diseases and muscle pathologies. In doing so, we highlight the potential importance of such genes in processes leading to skeletal muscle weakness in old age.
Role of water vapour in the absorption of nanosecond 266-nm laser pulses by atmospheric air
Authors: Kuryak A.N. , Tikhomirov B.A. 
Published: August 2020

Abstract

The absorption of the Nd : YAG fourth harmonic in air and binary mixtures of water vapour with nitrogen and oxygen at atmospheric pressure has been measured as a function of pulse energy (peak intensity). The mixtures obtained by adding equal amounts of water vapour to dry nitrogen and oxygen have been found to differ significantly in absorption. Preliminary quantitative data have been obtained for two- and three-photon absorption cross sections of water and oxygen molecules: σ
(2)(H2O) = (4 ± 1) ± 10–49 cm4 s and σ
(3)(O2) = (5.6 ± 1.4) ± 10–78 cm6 s2. The absorption of 266-nm pulses with peak intensities from 0.05 to 2 GW cm–2 in the near-surface atmosphere has been shown to be determined by two-photon absorption in water vapour and three-photon absorption in oxygen. In moist air containing 1 % water vapour, the absorption coefficient for 266-nm laser pulses exceeds that in dry air by four to five times. There is no absorption in nitrogen. We have developed a technique for photoacoustic measurements of multiphoton absorption cross sections in single-component gases and gas mixtures.
Relaxation oscillations in a bipolarised Nd : YAG laser with a Fabry – Perot cavity
Authors: Khandokhin P.A. 
Published: August 2020

Abstract
Based on the model of a bipolarised laser, which takes into account real orientations of absorbing and emitting dipoles of active centres in the unit cell of an Nd : YAG single crystal, we have shown that the appearance of low-frequency relaxation oscillations requires the participation of both competing pump channels through linearly and circularly polarised dipole transitions.
Lasing dynamics of diode-pumped Yb – Er laser with a passive Q switch exposed to high-power external light
Authors: Batura E.O. , Bobretsova Yu.K. , Bogdanovich M.V. , Veselov D.A. , Grigor’ev A.V. , Dudikov V.N. , Kot A.M. , Pikhtin N.A. , Ryabtsev A.G. , Ryabtsev G.I. , Slipchenko S.O. , Shpak P.V. 
Published: August 2020

Abstract
The temporal dynamics of diode-side-pumped Yb – Er laser, with a passive Co2+ : MgAl2O4
Q switch illuminated by a light beam (total fluence of 0.15 – 0.16 J cm−2) from a semiconductor pulsed module, is investigated. It is shown that, using this external illumination, one can change the lasing onset delay and the time jitter ΔT
gi. The dependence of ΔT
gi on the interval between the instant of switching the illumination module on and the lasing peak position t
i has a minimum at |t
i| ≈ 10 μs. The decrease in ΔT
gi with a change in |t
i| from 90 to 10 μs indicates that instant of lasing peak occurrence for the Yb – Er laser is partially controlled by the pulse from the highly stable semiconductor module. If |t
i| < 10 μs, the enhanced luminescence fluence in the cavity of Yb – Er laser exceeds 0.16 J cm−2; the light beam from the module does not affect much the lasing process in the ytterbium – erbium laser; and, as a consequence, the time jitter recovers the initial value.
Localised electromagnetic waves in a rhombic waveguide array with competing nonlinearities
Authors: Maimistov A.I. 
Published: August 2020

Abstract
We consider a model of a discrete photonic system representing a quasi-one-dimensional rhombic array of waveguides, where, in addition to the positive cubic nonlinearity, the negative quintic nonlinearity is taken into account for the material of which the central chain of the waveguides is made. The other two waveguide chains are made of an optically linear material. A continual approximation is used to obtain a solution for a system of coupled waves, which describes a wave localised in the transverse direction. In a certain special case, the competition of nonlinearities leads to the formation of a step-shaped distribution of the field intensities over the waveguides.
Cosmological dark matter amplification through dark torsion
Authors: Izaurieta Fernando , Lepe Samuel 
Published: August 2020

Abstract
A cosmological approach based on considering a cosmic background with non-zero torsion is shown in order to give an option of explaining a possible phantom evolution, not ruled out according to the current observational data. We revise some aspects of the formal schemes on torsion and, according them, we develop a formalism which can be an interesting alternative for exploring Cosmology.
Data-driven forward discretizations for Bayesian inversion
Authors: Bigoni D , Chen Y , Trillos N Garcia , Marzouk Y , Sanz-Alonso D 
Published: August 2020

Abstract
This paper suggests a framework for the learning of discretizations of expensive forward models in Bayesian inverse problems. The main idea is to incorporate the parameters governing the discretization as part of the unknown to be estimated within the Bayesian machinery. We numerically show that in a variety of inverse problems arising in mechanical engineering, signal processing and the geosciences, the observations contain useful information to guide the choice of discretization.
Tunable water-based metasurface for anomalous wave reflection
Authors: Jacobsen Rasmus E , Nielsen Jonas Ø , Lavrinenko Andrei V , Arslanagić Samel 
Published: August 2020

Abstract
Metasurfaces (MSs) are artificial structures which enable the full control of electromagnetic waves and they continue to be of great scientific importance. In particular, they can tailor their reflection and transmission properties by using electrically small metallic/dielectric scatterers with imprinted spatial phase variation. In the present work, we design and characterize a water-based MS with a tunable reflection at 1 GHz. The MS comprises a collection of water cylinders and we demonstrate its ability to reflect a normally incident wave at an angle of 51.3° and with a total reflection efficiency of 33%. A prototype was fabricated and is shown to exhibit an excellent agreement with the simulation results. The proposed water-based MS may serve as a cheap and bio-friendly tunable alternative for a variety of microwave communication systems.
Preparation of graphite-like carbon nitride (g-C3N4)/NiCo2S4 nanocomposite toward salient microwave characteristics and evaluation of medium influence on its microwave features
Authors: Peymanfar Reza , Ghorbanian-Gezaforodi Shaghayegh 
Published: August 2020

Abstract
In this paper, NiCo2S4 sulphide spinel nanoparticles are prepared using a modified solvothermal route, after which the obtained siegenite nanoparticles are tailored on graphite-like carbon nitride (g-C3N4) nanosheets. The morphology of tailored nanostructures is accomplished via an ion exchange process. Interestingly, the g-C3N4 stick structures are fabricated based on an innovative approach. Moreover, interfacial polarizations at heterojunction interfaces, and medium effects on microwave characteristics are examined, using polystyrene (PS) and polyvinylidene fluoride (PVDF) as polymeric matrices. The specimens are characterized via Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) analyses. The optical performance of nanostructures is studied by means of diffuse reflection spectroscopy (DRS) analysis, and is suggestive of a narrow band gap for NiCo2S4 and NiCo2S4/g-C3N4 nanostructures. Finally, the material’s microwave absorbing features are clarified using a vector network analyzer (VNA) instrument via a wave guide technique. The resulting significant microwave absorptions reveal that our g-C3N4/NiCo2S4/PVDF 40% nanocomposite exhibited seven notches of reflection loss (RL), more than 30 dB in its curve, at 1.75 mm in thickness, while its maximum RL was 59.39 dB at 13.07 GHz. Interestingly, this composite, in a mass fraction of 60%, illustrates an efficient bandwidth of 5.1 GHz (RL > 10 dB) at only 1 mm thickness. It is worth noting that the maximum RL of g-C3N4 stick structures/PVDF measures 74.53 dB at 14.86 GHz, with a broadband efficient bandwidth of 7.96 GHz (RL > 10 dB). More significantly, both g-C3N4/NiCo2S4/PVDF and NiCo2S4/PVDF demonstrated salient electromagnetic interference shielding effectiveness (SE) > 30 dB across both x- and ku-band frequencies.
Tailoring physical properties of WS2 nanosheets by defects control
Authors: Tao Lei , Song Yongli , Liu Jian , Wang Xianjie , Liu Zhiguo , Huo Mingxue , Wang Yang , Sui Yu 
Published: August 2020

Abstract
The controllable growth of high-quality transition metal dichalcogenides (TMDs) is crucial for their device applications, which rely on the atomic and quantitative understanding of the growth mechanism of TMDs. In this work, we propose a comprehensive picture of the growth of WS2 nanosheets via Monte Carlo simulation, and an extension of diffusion-limited growth under transition state theory is developed to describe heteroepitaxy growth of WS2. Theoretical results are in good agreement with the results of chemical vapor deposition that growth temperature dominates growth processes leading to samples with various densities of vacancy defects. The vacancy defects modify the photoluminescence and ferromagnetic behavior. Our work provides a pathway toward realizing controllable physical properties in 2D materials.
Molecular dynamics simulation of amine groups formation during plasma processing of polystyrene surfaces
Authors: Michlíček Miroslav , Hamaguchi Satoshi , Zajíčková Lenka 
Published: August 2020

Abstract
Plasma treatment and plasma polymerization processes aiming to form amine groups on polystyrene surfaces were studied in-silico with molecular dynamics simulations. The simulations were compared with two experiments, (i) plasma treatment in N2/H2 bipolar pulsed discharge and (ii) plasma polymerization in cyclopropylamine/Ar radio frequency (RF) capacitively coupled discharge. To model favorable conditions for the incorporation of primary amine groups, we assumed the plasma treatment as the flux of NH2 radicals and energetic NH3 ions, and the plasma polymerization as the flux of cyclopropylamine molecules and energetic argon ions. It is shown in both the simulation and the experiment that the polystyrene treatment by the bipolar pulsed N2/H2 plasmas with an applied voltage of about ±1 kV formed a nitrogen-rich layer of a thickness of only a few nm. The simulations also showed that, as the NH3 incident energy increases, the ratio of primary amines to the total number of N atoms on the surface decreases. It is because the energetic ion bombardment brakes up N–H bonds of primary amines, which are mostly brought to the surface by NH2 radical adsorption. Our previous experimental work on the CPA plasma polymerization showed that increased RF power invested in the plasma leads to the deposition of films with lower nitrogen content. The MD simulations showed an increase of the nitrogen content with the Ar energy and a limited impact of the energetic bombardment on the retention of primary amines. Thus, the results highlighted the importance of the gas-phase processes on the nitrogen incorporation and primary amines retention in the plasma polymers. However, the higher energy flux towards the growing film clearly decreases amount of hydrogen and increases the polymer cross-linking.
Influence of near-anode cusped magnetic field on the performance of a miniaturized cylindrical Hall thruster
Authors: Gao Yuanyuan , Fan Weina , Hu Peng , Liu Hui , Yu Daren 
Published: August 2020

Abstract
A near-anode cusped magnetic field topology is proposed for a 3 cm cylindrical Hall thruster (CHT), and its performance characteristics are investigated. The experimental results indicate that on imposing an anode voltage of 400 V, the thruster achieves a 2071 s specific impulse with a highly collimated plume. Compared with a conventional direct magnetic field, its thrust and anode efficiency are improved by 10.8% and 27.9%, respectively, which is due to the dramatic increase in the plume divergence efficiency (28.9%) and voltage utilization efficiency (6.7%). According to the analyses on the distribution characteristics of ion current density and ion energy, these performance improvements should be attributed to the downstream shift of both the ionization and acceleration regions. This work provides some design ideas on the magnetic field optimization of CHTs.
Differences in power law growth over time and indicators of COVID-19 pandemic progression worldwide
Authors: Merrin Jack 
Published: August 2020

Abstract
Error analysis and data visualization of positive COVID-19 cases in 27 countries have been performed up to August 8, 2020. This survey generally observes a progression from early exponential growth transitioning to an intermediate power-law growth phase, as recently suggested by Ziff and Ziff. The occurrence of logistic growth after the power-law phase with lockdowns or social distancing may be described as an effect of avoidance. A visualization of the power-law growth exponent over short time windows is qualitatively similar to the Bhatia visualization for pandemic progression. Visualizations like these can indicate the onset of second waves and may influence social policy.
Shape of population interfaces as an indicator of mutational instability in coexisting cell populations
Authors: Castillo Clarisa E , Lavrentovich Maxim O 
Published: August 2020

Abstract
Cellular populations such as avascular tumors and microbial biofilms may ‘invade’ or grow into surrounding populations. The invading population is often comprised of a heterogeneous mixture of cells with varying growth rates. The population may also exhibit mutational instabilities, such as a heavy deleterious mutation load in a cancerous growth. We study the dynamics of a heterogeneous, mutating population competing with a surrounding homogeneous population, as one might find in a cancerous invasion of healthy tissue. We find that the shape of the population interface serves as an indicator for the evolutionary dynamics within the heterogeneous population. In particular, invasion front undulations become enhanced when the invading population is near a mutational meltdown transition or when the surrounding ‘bystander’ population is barely able to reinvade the mutating population. We characterize these interface undulations and the effective fitness of the heterogeneous population in one- and two-dimensional systems.
Formation of α’ titanium welds by friction stir welding
Authors: Amirov A I , Eliseev A A , Beloborodov V A , Chumaevskii A V , Gurianov D A 
Published: August 2020

Abstract
In the present study, investigation of the macrostructure of α’ titanium alloy weld produced by the friction stir welding has been carried out. The welding process modes were also selected. It is shown that in case of insufficient load on the tool, an open weld defect is formed. Increasing the load (with decreasing RPM) eliminates the open tunnel and minimizes defects. Despite the presence of defects, the strength of welds has reached the strength of the initial material. As a result of FSW, grain size has been reduced by 7.3 times, but the load increase has not affected the grain structure. The results of the research show that the part of welding tool had been stirred in the structure of weld. However, nickel base alloy tool had passed about 500 mm of weld, before starting to wear out.
Deformation behavior of stainless steel under uniaxial tension
Authors: Nikonova A M , Li Y V , Barannikova S A 
Published: August 2020

Abstract
The present work is devoted to the study of the laws of macroscopic localization of plastic deformation of austenitic stainless steel AISI 321 at low and high temperatures. The studies of AISI 321 steel found that at the stages of linear strain hardening, the propagation velocity of the localized plastic deformation centers and the spatial period of local elongation change when test temperature increases by the exponential law. Patterns of plastic strain localization as single bands are due to the Portevin – Le Chatelier effect on jerky flow.