bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reducing Complexity in PTS Scheme using Optimization Techniques to reduce PAPR in OFDM Systems
Authors: Sarankumar R. , Sumathi K. , Sai Sravanthi G. , Venkateswarlu B. , Rajasekar P. 
Published: February 2021

Abstract
OFDM is a technique used to combat Inter Symbol Interference (ISI) in wireless communication systems. OFDM offers high reliable data rate over frequency selective channels. But the drawback is high Peak to Average Power Ratio (PAPR) which will affect the power amplifier in the RF front end. Partial Transmit Sequence (PTS) has proven to be the efficient technique to minimize the PAPR in OFDM systems and it does not affect the Bit Error Rate (BER) much. But PTS in turn suffers from high search complexity. The optimization algorithms can offer a tradeoff between the search complexity and PAPR reduction. In this work the phase factor optimization in PTS scheme is converted into a one dimensional optimization problem. Genetic Algorithm (GA), Simulated Annealing (SA) and Particle Swarm Optimization (PSO) are applied to the problem defined. They are also compared in terms of PAPR reduction and complexity. The fitness functions are chosen according to the optimization technique.
Antibacterial PLGA and PCL membranes, modified by magnetron sputtering method of copper target
Authors: Badaraev A D , Sidelev D V , Tverdokhlebov S I 
Published: February 2021

Abstract
The paper discusses barrier membranes which were formed from poly(lactide-co-glycolide) and polycaprolactone by electrospinning method. Then, plasma modification of membranes was carried out by magnetron sputtering of copper target in argon atmosphere. The morphology, elemental composition, mechanical and antibacterial properties of the obtained samples were investigated. Modification with copper in the magnetron discharge plasma allows maintaining the original characteristics of pristine polymeric samples and imparting antibacterial properties to them.
Results of long-term permeability of small-diameter vascular prostheses modified by pro-angiogenic factors and athrombogenic drug coating (model of large laboratory animals)
Authors: Krivkina E O , Mironov A V , Shabaev A R , Rezvova M A , Velikanova E A , Tkachenko V O , Khanova M Yu , Sergeeva T Y , Krutitskiy S S , Antonova L V 
Published: February 2021

Abstract
Developed for bypass surgery, tissue-engineered vascular grafts should remain passable after implantation and have high rate of endothelialization to ensure long-term patency, atrombogenicity and biocompatibility. This study was aimed at assessing the long-term patency of polyhydroxybutyrate/valerate (PHBV)/polycaprolactone (PCL) vascular grafts modified by pro-angiogenic factors and athrombogenic drug coating in a large laboratory animal model.
The technology for concrete production using an activated mixture of wood processing waste and sand
Authors: Kuznetsova I N 
Published: February 2021

Abstract
The article presents a technology for producing concrete using the waste of wood processing plants as the concrete filler. The waste was activated by mechanical, hydromechanical and hydromechanochemical technologies in a centrifugal disk installation. The established optimal ratio of sand to the waste (activated mixture) is 70:30%. The accepted fraction of the activated mixture is 10 wt% (of the mass of cement). The tests confirmed the reduction in the average density of the cement stone, while preserving its strength; the thermophysical properties of the stone increase.
Damage accumulation after temperature aging in structural GFRP in interlayer shear tests
Authors: Lobanov D S , Zubova E M 
Published: February 2021

Abstract
A series of quasi-static tests of the structural fiberglass reinforced polymers samples in interlayer shear by the short-beam method were carried out in this work. Mechanical tests were carried out after preliminary temperature aging with different temperature regimes and exposure duration. Diagrams of dependence of the residual interlayer strength degradation on the mode of preliminary aging are constructed. An investigation of the microstructure of GFRP specimens before and after quasi-static tests in interlayer shear was carried out. During the experimental studies the control of the damage accumulation processes and destruction was carried out using the acoustic emission method (AE). Analysis of the AE signal parameters made it possible to assess the prevalence of different destruction types of composites depending on the mode of preliminary aging.
Surfacing of Rapidly-Wearing Parts
Authors: Nazarko A S , Plomodyalo R L 
Published: February 2021

Abstract
This paper considers the possibility of creating cast rods for surfacing of rapidly-wearing tillage tool parts of agricultural machinery, which would not contain scarce alloying elements and provide a wear-resistant deposited metal having high hardness and high resistance to crack formation in hardened condition. It was found that with an increase in boron concentration to 0.7 … 0.8%, the amount of boride eutectic increases, which helps to prevent crystallization cracks, and the impact toughness first increases, and then slightly decreases, which is associated with the appearance of large boride inclusions.
Features of reactive SPS of SrTiO3–TiO2biphasic ceramics
Authors: Zavjalov A P , Shichalin O O , Tikhonov S A , Kosyanov D Yu 
Published: February 2021

AbstractSrTiO3and biphasic SrTiO3–TiO2ceramics were obtained by reactive spark plasma sintering (SPS) of mixtures of strontium carbonate SrCO3and titanium dioxide TiO2. For monophasic SrTiO3, there is a linear seal of the mixture in the heating process. Biphasic ceramics at a temperature of about 1320°C are characterized by eutectic melting of the SrTiO3–TiO2mixture, which allowed estimating the temperature gradient in the system ∼77°/sm. Microstructural studies have confirmed the formation of biphasic SrTiO3–TiO2ceramics with a homogeneous structure and a grain size of 1÷2 μm.
Mechanochemical synthesis and antibacterial effect of CuBi2O4 nanoparticles against P. aeruginosa and S. aureus
Authors: Vázquez-Olmos A R , Rubiales-Martinez A , Almaguer-Flores A , Vega-Jiménez A L , Prado-Prone G 
Published: February 2021

Abstract
Nanoparticles (NPs) of CuBi2O4 with an average size around 25 nm were obtained by a novel and eco-friendly synthesis method. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) reveal that CuBi2O4 NPs possess a tetragonal crystal structure. These NPs were characterised by Raman scattering, ultraviolet-visible (UV-Vis) absorption, photoluminescence (PL), and electron paramagnetic resonance (EPR) spectroscopies. Furthermore, an in vitro study of the antibacterial effect of CuBi2O4 NPs against two bacterial strains, Pseudomonas aeruginosa (ATCC 43636) and Staphylococcus aureus (ATCC 25923), was carried out. The results obtained from the counting of colony-forming units (CFUs) and by the XTT-PMS cell viability assay showed an inhibition of the bacterial growth by 88%–87% for P. aeruginosa and 100% for S. aureus, at 50 mg ml−1 of NPs concentration. The results of this work suggest that these nanoparticles have the potential to be used as antibacterial agents by embedding them into different surfaces or being dispersed in a coating, to prevent the bacterial colonisation.
Epitaxy of boron nitride monolayers for graphene-based lateral heterostructures
Authors: Wrigley James , Bradford Jonathan , James Tyler , Cheng Tin S , Thomas James , Mellor Christopher J , Khlobystov Andrei N , Eaves Laurence , Foxon C Thomas , Novikov Sergei V , Beton Peter H 
Published: February 2021

Abstract
Monolayers of hexagonal boron nitride (hBN) are grown on graphite substrates using high-temperature molecular beam epitaxy (HT-MBE). The hBN monolayers are observed to grow predominantly from step edges on the graphite surface and exhibit a strong dependence of the morphology, including the dominant crystallographic edge, of the hBN monolayers, on the growth temperature, as well as systematic variations in growth rate and coverage, and significant differences in the growth at monolayer and multilayer graphite steps. At graphite monolayer steps hBN grows laterally across the surface on the lower terrace, but hBN growth on the upper side of the graphite step is more limited and is nucleated by three-dimensional clusters. Multilayer graphite steps exhibit a much higher density of non-planar hBN aggregates and growth on both the upper and lower terraces occurs. The results show that the hBN monolayer growth edge type, hBN island shape and the presence of hBN aggregates can be controlled in HT-MBE, with the highest quality layers grown at a substrate temperature of about 1390 °C. Sequential HT-MBE growth of hBN, graphene (G) and a second cycle of hBN growth results in the formation of monolayer thick lateral hBN–G–hBN heterostructures, in which a strip of G is embedded between monolayers of hBN.
Modified fiber optic sensor for highly precise identification of mercuric ion (Hg2+) concentrations in aqueous solution
Authors: Qazi Hummad Habib , Salim Mohd Rashidi bin , Bin Mohd Supa’at Abu Sahmah , Ahmed Iftikhar , Abbasi Misbah Sehar , Ali Muhammad Mahmood , Idrus Sevia Mahdaliza , Mohammad Abu Bakar bin , Sultan Irshad Muhammad , Yasmeen Farhat 
Published: February 2021

Abstract
A fiber optic sensor for monitoring mercuric (Hg2+) ions in the aqueous sample have been developed based on modified cladding. To fabricate a D-shaped sensing zone onto the multimode optical fiber lengthwise polishing was utilized using a mechanical end and edge polishing system. The produced sensing region has dimensions of 10 mm × 125 μm × 62 μm (l × w × h). A 2 μm thin layer of Al2O3 nanoparticles sensitized with 4-(2-pyridylazo)-resorcinol was deposited onto the sensing element of multimode fiber optic sensor to make it sensitive and selective for Hg2+ ions. The analytical results demonstrate that the sensing device has a linear response for Hg2+ ions concentration over a range from 4 to 16 ppm along with a 4 ppm limit of detection in an aqueous sample at room temperature. The selectivity of the sensor is examined for the recognition of Hg2+ ions in presence of other cations such as zinc and/or lead ions up to 16 ppm in an aqueous solution. The main merits of this fabricated sensor are easy and safe installation, rapid response, enhanced linear response range, and better selectivity towards Hg2+ ions.
Deep-learning-based quantum vortex detection in atomic Bose–Einstein condensates
Authors: Metz Friederike , Polo Juan , Weber Natalya , Busch Thomas 
Published: February 2021

Abstract
Quantum vortices naturally emerge in rotating Bose–Einstein condensates (BECs) and, similarly to their classical counterparts, allow the study of a range of interesting out-of-equilibrium phenomena, such as turbulence and chaos. However, the study of such phenomena requires the determination of the precise location of each vortex within a BEC, which becomes challenging when either only the density of the condensate is available or sources of noise are present, as is typically the case in experimental settings. Here, we introduce a machine-learning-based vortex detector motivated by state-of-the-art object detection methods that can accurately locate vortices in simulated BEC density images. Our model allows for robust and real-time detection in noisy and non-equilibrium configurations. Furthermore, the network can distinguish between vortices and anti-vortices if the phase profile of the condensate is also available. We anticipate that our vortex detector will be advantageous for both experimental and theoretical studies of the static and dynamic properties of vortex configurations in BECs.
Sodium/Glucose Cotransporter 2 Inhibitors and the Risk of Diabetic Ketoacidosis: An Example of Complementary Evidence for Rare Adverse Events
Authors: Alkabbani Wajd , Pelletier Ryan , Gamble John-Michael 
Published: February 2021

Abstract
Evidence from observational studies may be considered complementary to that of randomized controlled trials (RCTs), particularly when assessing rare outcomes of drug therapies. Sodium/glucose cotransporter 2 (SGLT-2) inhibitors are a novel class of antidiabetic agents that have been linked to an increased risk of diabetic ketoacidosis (DKA). We conducted a systematic review and separately meta-analyzed data from RCTs (n = 18; 2013–2019) and cohort studies (n = 7; 2017–2020) to assess the consistency of the magnitude of association between SGLT-2 inhibitors and DKA risk. We illustrate the strengths and weaknesses of the 2 designs. Results from RCTs and observational studies consistently showed almost a doubling in the risk of DKA among patients using an SGLT-2 inhibitor as compared with placebo or an active comparator. In a random-effects model, the pooled relative risk was 2.08 (95% confidence interval (CI): 1.28, 3.40) from placebo-controlled RCTs and 0.82 (95% CI: 0.25, 2.68) from active-comparator RCTs. The pooled adjusted hazard ratio from observational studies was 1.74 (95% CI: 1.28, 2.38). Notably, the 2 designs complement each other in several domains, including external and internal validity and power. This demonstrates a need for more comprehensive evidence when assessing rare adverse events for both sources.
Brain Activity Fluctuations Propagate as Waves Traversing the Cortical Hierarchy
Authors: Gu Yameng , Sainburg Lucas E , Kuang Sizhe , Han Feng , Williams Jack W , Liu Yikang , Zhang Nanyin , Zhang Xiang , Leopold David A , Liu Xiao 
Published: February 2021

Abstract
The brain exhibits highly organized patterns of spontaneous activity as measured by resting-state functional magnetic resonance imaging (fMRI) fluctuations that are being widely used to assess the brain’s functional connectivity. Some evidence suggests that spatiotemporally coherent waves are a core feature of spontaneous activity that shapes functional connectivity, although this has been difficult to establish using fMRI given the temporal constraints of the hemodynamic signal. Here, we investigated the structure of spontaneous waves in human fMRI and monkey electrocorticography. In both species, we found clear, repeatable, and directionally constrained activity waves coursed along a spatial axis approximately representing cortical hierarchical organization. These cortical propagations were closely associated with activity changes in distinct subcortical structures, particularly those related to arousal regulation, and modulated across different states of vigilance. The findings demonstrate a neural origin of spatiotemporal fMRI wave propagation at rest and link it to the principal gradient of resting-state fMRI connectivity.
Factors Associated With Peripartum Virologic Suppression in Eastern Cape Province, South Africa: A Retrospective Cross-Sectional Analysis
Authors: Adeniyi Oladele Vincent , Obi Chikwelu Larry , Goon Daniel Ter , Iweriebor Benson , Selanto-Chairman Nonkosi , Carty Craig , Avramovic Gordana , Ajayi Anthony Idowu , Lambert John , Okoh Anthony 
Published: February 2021

Abstract

Background
This study describes the characteristics of pregnant women on antiretroviral therapy (ART) and the rate of peripartum virologic suppression in a large prevention of mother-to-child transmission cohort who delivered in some selected maternity centers in Eastern Cape Province, South Africa. In addition, the study examines the factors associated with virologic suppression in the cohort.

Methods
This multicenter, retrospective cross-sectional analysis included medical data of 1709 women with human immunodeficiency virus between September 2015 and May 2016 in Eastern Cape Province. The main outcome measure was the rate of peripartum virologic suppression, defined as viral load (VL) &lt;1000 copies/mL and undetectable viremia (VL &lt;20 copies/mL). Correlates of peripartum virologic suppression and undetectable viremia were examined by fitting logistic regression model analysis.

Results
Of 1463 women with available VL results, the overall rate of peripartum suppression was 82%, and undetectable viremia was 56.9%. Being aged 24 years or younger (adjusted odds ratio [AOR], 0.68 [95% confidence interval {CI}, .48–.94]), smoking during pregnancy (AOR, 0.50 [95% CI, .28–.90]), and starting ART in the first trimester were associated with lower odds of viral suppression (&lt;1000 copies/mL). Women who had never defaulted ART had an increased odds of having an undetectable VL (AOR, 3.09 [95% CI, 2.12–4.49]) and virologic suppression (AOR, 3.88 [95% CI, 2.62–5.74]) compared to those who defaulted.

Conclusions
More than half of the women achieved undetectable VL, and 4 in 5 women achieved viral suppression at delivery in the region. Early antenatal booking, combined with enhanced adherence support for pregnant women on ART, would be crucial toward achieving the goal of elimination of mother-to-child transmission in the region.
Resources for Families during COVID-19: A Content Analysis of Information Provided on School District Web Sites
Authors: Iachini Aidyn L , Childs Tasha M 
Published: February 2021

AbstractThe novel coronavirus (COVID-19) pandemic has disrupted the educational system not only in regard to teaching and learning, but also in relation to the other services and supports (mental health services, meal and nutrition programs, and so on) provided to students and families. School district Web sites are critical access points for families during this crisis to learn information about key resources being provided during school closure. This study used content analysis to examine whether school district Web sites in one southeastern state provided information about COVID-19 and 11 other resources. Findings indicate that about half of the Web sites provided both COVID-19 information and additional resources. Few districts provided information on resources for students with disabilities, a subgroup of students at heightened vulnerability during this time of virtual learning. Approximately a third of school district Web sites provided no information on COVID-19 or any of the other resources. The article concludes with a discussion of the implications for school social workers related to crisis response and leadership around contributing to efforts that aim to address educational disparities and inequities and maximize student success during this time of crisis.
Disability, Loneliness and Health in the UK: cross-sectional survey
Authors: Emerson Eric , Stancliffe Roger , Fortune Nicola , Llewellyn Gwynnyth 
Published: February 2021

Abstract

Background
Research has suggested that exposure to loneliness can have a powerful detrimental impact on health, including mental health. Addressing socially determined health inequity requires understanding of the situation of marginalized or vulnerable groups. People with disability are increasingly being recognized as one such group. Little population-based research has addressed the association between loneliness and health among working age adults with and without disability.

Methods
Secondary analysis of data collected in waves 8 and 9 of Understanding Society, the UK’s main annual household panel study.

Results
Rates of exposure to substantial loneliness were 25.4% (95%CI 23.5–27.3%) among adults with persistent disability (disability at W8 and W9), 15.4% (13.3–17.5%) among adults with disability onset (disability at W9 only), 12.3% (10.1–14.5%) among adults with disability offset (disability at W8 only), and 6.9% (6.5–7.3%) among adults with no disability. Exposure to loneliness was positively associated with the incidence (GHQ-12) and prevalence (SF-12 Mental) of mental health problems, but not the prevalence of physical health problems (SF-12 Physical). Disability status appeared to moderate the association between loneliness and health, with the difference between the persistent disability and no disability group increasing with exposure to greater levels of loneliness.

Conclusion
Loneliness may be an important determinant of the poorer mental health of working age adults with disability in the UK. Exposure rates are significantly higher than among the non-disabled population. The strength of association between exposure to loneliness and poorer mental health is greater for people with persistent disability than people with no disability.
Non-contrast transoesophageal echo-guided transapical transcatheter aortic valve replacement: 10-year experience of a renoprotective strategy
Authors: Mosquera Victor X , Bouzas-Mosquera Alberto , Vilela-González Yago , Oujo-González Bárbara , Velasco-García Carlos , Cuenca-Castillo José J , Herrera-Noreña José M 
Published: February 2021

Abstract

OBJECTIVES
This study aims to evaluate the efficacy, safety and long-term outcomes of a renoprotective non-contrast, transoesophageal echocardiography-guided transapical (TA) transcatheter aortic valve replacement (TAVR) strategy with a balloon-expandable prosthesis, as well as to determine its impact on renal function.

METHODS
Between 2009 and 2019, 200 consecutive patients underwent a non-contrast, transoesophageal echocardiography-guided TA TAVR with a balloon-expandable prosthesis.

RESULTS
The device success rate was 95.5%. Transoesophageal echocardiography-guided deployment demonstrated a low rate of procedure-related complications: 9.5% of acute kidney injury, 8% postoperative bleeding, 6% low-cardiac output, 4.5% postprocedural aortic regurgitation ≥+2, 4% implantation of permanent pacemaker and 2% stroke. There were no significant differences between preoperative and on discharge estimated glomerular filtration rate (53.9 ± 22.2 vs 54.3 ± 22.9 ml/min/1.73 m2, P = 0.60). Logistic regression analysis confirmed postoperative bleeding as an independent predictor for acute kidney injury (odds ratio (OR) 11.148, 95% confidence interval 3.537–35.140, P &lt; 0.001). In-hospital mortality was 7.5%. The mean follow-up was 48.5 ± 39.9 months. Renal function and patient’s chronic kidney disease stage did not significantly vary during follow-up. Long-term cumulative survival at 1, 5 and 10 years was 84.2 ± 0.027%, 42.9 ± 0.038% and 32.5 ± 0.044%, respectively. Renal function affected on neither in-hospital mortality nor long-term survival.

CONCLUSIONS
Non-contrast, transoesophageal echocardiography-guided TA TAVR is a safe and reproducible technique with a low incidence of periprocedural complications that avoids the use of contrast and mitigates the incidence of acute kidney injury.
Asynchronous quadratic control for constrained hidden markov jump linear systems with incomplete MTPM and MOCPM
Authors: Zhu Jin , Xia Kai , Dullerud Geir E 
Published: February 2021

AbstractThis paper investigates the quadratic optimal control problem for constrained Markov jump linear systems with incomplete mode transition probability matrix (MTPM). Considering original system mode is not accessible, observed mode is utilized for asynchronous controller design where mode observation conditional probability matrix (MOCPM), which characterizes the emission between original modes and observed modes is assumed to be partially known. An LMI optimization problem is formulated for such constrained hidden Markov jump linear systems with incomplete MTPM and MOCPM. Based on this, a feasible state-feedback controller can be designed with the application of free-connection weighting matrix method. The desired controller, dependent on observed mode, is an asynchronous one which can minimize the upper bound of quadratic cost and satisfy restrictions on system states and control variables. Furthermore, clustering observation where observed modes recast into several clusters, is explored for simplifying the computational complexity. Numerical examples are provided to illustrate the validity.