bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of COVID-19 Pandemic on Total Mortality in Poland
Authors: Barański Kamil , Brożek Grzegorz , Kowalska Małgorzata , Kaleta-Pilarska Angelina , Zejda Jan Eugeniusz
Published: April 2021

Background: According to published data the number of deaths attributed to COVID-19 is underestimated between 30 and 80%. Aim: The aim of this study is to assess the impact of COVID-19 on total mortality of Poland and the Silesian voivodship. Methods: Secondary epidemiological data on COVID-19 deaths were obtained from the Ministry of Health registry and data on total mortality were gathered from the National Statistical Office and Registry Office in Poland. Three scenarios were used to estimated COVID-19 deaths: real number + an extra 30%, 60%, and 70% excess total deaths. Results: In 2020, there were 73,254, 64,584, and 67,677 excess deaths in comparison to 2017–2019, respectively. For the Silesian voivodship, it was 8339, 7946, and 8701, respectively. The total mean increase in deaths was 16% for the whole country and the Silesian voivodship. The simulation for 30% extra COVID-19 deaths gave COVID-19 mortality equal to 12.5%; n = 50,708 deaths, for extra 60%; 17.9% n = 72,866 and for extra 70%; 19.7% n = 80,251 for Poland; and 11.9% (n = 6072), 17.2% (n = 8740), 24.2% (n = 12,297), respectively, for the Silesian voivodship. Conclusions: The participation of COVID-19 in total deaths should not exceed 20% for Poland and 24% for the Silesian voivodship in 2020.
The Association between Migraine and Abdominal Aortic Aneurysms: A Nationwide Population-Based Cohort Study
Authors: Lin Jou-Yu , Tung Che-Se , Wang Jen-Chun , Chien Wu-Chien , Chung Chi-Hsiang , Lin Chih-Yuan , Tsai Shih-Hung
Published: April 2021

Previous studies have indicated that patients with migraine have a higher prevalence of risk factors known to be associated with cardiovascular diseases. There are also shared epidemiology and molecular mechanisms between migraine and abdominal aortic aneurysm (AAA). We hypothesized that patients with migraine could have an increased risk of AAA. To test this hypothesis, we used the National Health Insurance Research Database (NHIRD) to evaluate whether associations exist between migraine and AAA. The data for this nationwide population-based retrospective cohort study were obtained from the NHIRD in Taiwan. The assessed study outcome was the cumulative incidence of AAA in patients with migraine during a 15-year follow-up period. Among the 1,936,512 patients from the NHIRD, 53,668 (2.77%) patients were identified as having been diagnosed with migraine. The patients with migraine had a significantly higher cumulative risk of 3.558 of developing an AAA 5 years after the index date compared with the patients without migraine. At the end of the 15-year follow-up period, a significantly higher incidence of AAA (0.98%) was observed in the patients with migraine than in those without migraine (0.24%). We revealed an association between the development of migraine and AAA.
Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD)—A Condition Associated with Heightened Sympathetic Activation
Authors: Carnagarin Revathy , Tan Kearney , Adams Leon , Matthews Vance B. , Kiuchi Marcio G. , Marisol Lugo Gavidia Leslie , Lambert Gavin W. , Lambert Elisabeth A. , Herat Lakshini Y. , Schlaich Markus P.
Published: April 2021

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common liver disease affecting a quarter of the global population and is often associated with adverse health outcomes. The increasing prevalence of MAFLD occurs in parallel to that of metabolic syndrome (MetS), which in fact plays a major role in driving the perturbations of cardiometabolic homeostasis. However, the mechanisms underpinning the pathogenesis of MAFLD are incompletely understood. Compelling evidence from animal and human studies suggest that heightened activation of the sympathetic nervous system is a key contributor to the development of MAFLD. Indeed, common treatment strategies for metabolic diseases such as diet and exercise to induce weight loss have been shown to exert their beneficial effects at least in part through the associated sympathetic inhibition. Furthermore, pharmacological and device-based approaches to reduce sympathetic activation have been demonstrated to improve the metabolic alterations frequently present in patients with obesity, MetSand diabetes. Currently available evidence, while still limited, suggests that sympathetic activation is of specific relevance in the pathogenesis of MAFLD and consequentially may offer an attractive therapeutic target to attenuate the adverse outcomes associated with MAFLD.
Mangiferin Inhibits Apoptosis in Doxorubicin-Induced Vascular Endothelial Cells via the Nrf2 Signaling Pathway
Authors: Ismail Mohammad Bani , Rajendran Peramaiyan , AbuZahra Hamad Mohammed , Veeraraghavan Vishnu Priya
Published: April 2021

Doxorubicin increases endothelial permeability, hence increasing cardiomyocytes’ exposure to doxorubicin (DOX) and exposing myocytes to more immediate damage. Reactive oxygen species are major effector molecules of doxorubicin’s activity. Mangiferin (MGN) is a xanthone derivative that consists of C-glucosylxanthone with additional antioxidant properties. This particular study assessed the effects of MGN on DOX-induced cytotoxicity in human umbilical vein endothelial cells’ (HUVECs’) signaling networks. Mechanistically, MGN dramatically elevated Nrf2 expression at both the messenger RNA and protein levels through the upregulation of the PI3K/AKT pathway, leading to an increase in Nrf2-downstream genes. Cell apoptosis was assessed with a caspase-3 activity assay, transferase-mediated dUTP-fluorescein nick end labeling (TUNEL) staining was performed to assess DNA fragmentation, and protein expression was determined by Western blot analysis. DOX markedly increased the generation of reactive oxygen species, PARP, caspase-3, and TUNEL-positive cell numbers, but reduced the expression of Bcl-2 and antioxidants’ intracellular concentrations. These were effectively antagonized with MGN (20 μM), which led to HUVECs being protected against DOX-induced apoptosis, partly through the PI3K/AKT-mediated NRF2/HO-1 signaling pathway, which could theoretically protect the vessels from severe DOX toxicity.
Leucine Reconstitutes Phagocytosis-Induced Cell Death in E. coli-Infected Neonatal Monocytes—Effects on Energy Metabolism and mTOR Signaling
Authors: Dreschers Stephan , Ohl Kim , Möllmann Julia , Tenbrock Klaus , Orlikowsky Thorsten W.
Published: April 2021

MΦ differentiate from circulating monocytes (Mo). The reduced ability of neonatal Mo to undergo apoptosis after E. coli infection (phagocytosis-induced cell death (PICD)) could contribute to sustained inflammatory processes. The objective of our study was to investigate whether immune metabolism in Mo can be modified to gain access to pro-apoptotic signaling. To this end, we supplemented Mo from neonates and from adults with the branched amino acid leucine. In neonatal Mo, we observed increased energy production via oxidative phosphorylation (Oxphos) after E. coli infection via Seahorse assay. Leucine did not change phagocytic properties. In neonatal Mo, we detected temporal activation of the AKT and mTOR pathways, accompanied with subsequent activation of downstream targets S6 Kinase (S6K) and S6. FACS analyses showed that once mTOR activation was terminated, the level of anti-apoptotic BCL-2 family proteins (BCL-2; BCL-XL) decreased. Release of cytochrome C and cleavage of caspase-3 indicated involvement of the intrinsic apoptotic pathway. Concomitantly, the PICD of neonatal Mo was initiated, as detected by hypodiploid DNA. This process was sensitive to rapamycin and metformin, suggesting a functional link between AKT, mTOR and the control of intrinsic apoptotic signaling. These features were unique to neonatal Mo and could not be observed in adult Mo. Supplementation with leucine therefore could be beneficial to reduce sustained inflammation in septic neonates.
The Increasing Impact of Translational Research in the Molecular Diagnostics of Neuromuscular Diseases
Authors: Yubero Dèlia , Natera-de Benito Daniel , Pijuan Jordi , Armstrong Judith , Martorell Loreto , Fernàndez Guerau , Maynou Joan , Jou Cristina , Roldan Mònica , Ortez Carlos , Nascimento Andrés , Hoenicka Janet , Palau Francesc
Published: April 2021

The diagnosis of neuromuscular diseases (NMDs) has been progressively evolving from the grouping of clinical symptoms and signs towards the molecular definition. Optimal clinical, biochemical, electrophysiological, electrophysiological, and histopathological characterization is very helpful to achieve molecular diagnosis, which is essential for establishing prognosis, treatment and genetic counselling. Currently, the genetic approach includes both the gene-targeted analysis in specific clinically recognizable diseases, as well as genomic analysis based on next-generation sequencing, analyzing either the clinical exome/genome or the whole exome or genome. However, as of today, there are still many patients in whom the causative genetic variant cannot be definitely established and variants of uncertain significance are often found. In this review, we address these drawbacks by incorporating two additional biological omics approaches into the molecular diagnostic process of NMDs. First, functional genomics by introducing experimental cell and molecular biology to analyze and validate the variant for its biological effect in an in-house translational diagnostic program, and second, incorporating a multi-omics approach including RNA-seq, metabolomics, and proteomics in the molecular diagnosis of neuromuscular disease. Both translational diagnostics programs and omics are being implemented as part of the diagnostic process in academic centers and referral hospitals and, therefore, an increase in the proportion of neuromuscular patients with a molecular diagnosis is expected. This improvement in the process and diagnostic performance of patients will allow solving aspects of their health problems in a precise way and will allow them and their families to take a step forward in their lives.
A Peculiar New Genus of Bibionomorpha (Diptera) with Brachycera-Like Modification of Antennae from Mid-Cretaceous Amber of Myanmar
Authors: Ševčík Jan , Skartveit John , Krzemiński Wiesław , Skibińska Kornelia
Published: April 2021

A new fossil genus of Bibionidae (Diptera: Bibionomorpha), Burmahesperinus gen. nov., from the mid-Cretaceous Burmese amber, is described and illustrated (type species Burmahesperinus antennatus sp. nov., the other two species included are B. conicus sp. nov. and B. pedicellatus sp. nov.). The new genus is tentatively placed in a new subfamily, Burmahesperininae subfam. nov. of the family Bibionidae. Its possible phylogenetic position is briefly discussed. The new genus, as well as the subfamily, possesses the wing venation similar to the recent genus Hesperinus Walker, 1848, in combination with Brachycera-like modification of both the male and female antenna and the overall habitus typical of fungus gnats (Sciaroidea).
Culicoides insignis Lutz, 1913 (Diptera: Ceratopogonidae) Biting Midges in Northeast of Brazil
Authors: Rios Raisa Rodrigues Santos , Santarém Maria Clara Alves , Ribeiro Júnior Karlos Antônio Lisboa , de Melo Breno Araujo , da Silva Sybelle Georgia Mesquita , da Silva Neuriane Cavalcante , dos Santos Vitória Regina Viana , dos Santos Jakeline Maria , Santana Antônio Euzébio Goulart , Fraga Angelina Bossi
Published: April 2021

The species of the Culicoides genus are hematophagous, and some of them are vectors of important human and animal diseases. This group of insects is distributed worldwide, varying according to local species. Knowledge of the geographic distribution of specific species is crucial for the development and implementation of control strategies. The aim of this work was to investigate the occurrence of Culicoides in the state of Alagoas in northeast Brazil. Midges were captured with CDC light traps, and their identification and morphological analyses were performed by the Ceratopogonidae Collection of the Oswaldo Cruz Foundation (FIOCRUZ/CCER) in Rio de Janeiro, Brazil. Morphological analyses were performed using the key to Culicoides from the guttatus group and comparison with other deposited specimens. DNA sequencing, genetic analysis and comparison with sequences in the Genbank database, confirmed the identification of the flies as Culicoides insignis. This was the first formal report of C. insignis being found in Alagoas.
Biological Strategies of Invasive Bark Beetles and Borers Species
Authors: Demidko Denis A. , Demidko Natalia N. , Mikhaylov Pavel V. , Sultson Svetlana M.
Published: April 2021

The present study attempts to identify the biological characteristics of invasive (high-impact in the secondary area) bark beetles and borers species, contributing to their success in an invaded area. We selected 42 species based on the CABI website data on invasive species and information on the most studied regional faunas. Four groups of species with different invasion strategies were identified based on the cluster and factor analysis. The first one (inbred strategy) is characterized by flightless males, xylomycetophagy, low fecundity (~50 eggs), inbreeding, polyvoltinism, and polyphagy. Species with an aggressive strategy are poly- or monovoltine, feeds on a limited number of hosts, larval feeding on the inner bark, are often associated with phytopathogens, and produce aggregation pheromones. Representatives of the polyphagous strategy have a wide range of hosts, high fecundity (~150 eggs), larval feeding on wood, and their life cycle is at least a year long. For the intermediate strategy, the typical life cycle is from a year or less, medium fecundity, feed on inner bark tissues, mono- or oligophagy. Comparison with low-impact alien species showed that the most significant traits from the viewpoint of the potential danger of native plant species are high fecundity, polyvoltinism, presence of symbiotic plant pathogens, long-range or aggregation pheromones.
A Heterozygous Mutation in Cardiac Troponin T Promotes Ca2+ Dysregulation and Adult Cardiomyopathy in Zebrafish
Authors: Kamel Sarah M. , Koopman Charlotte D. , Kruse Fabian , Willekers Sven , Chocron Sonja , Bakkers Jeroen
Published: April 2021

Cardiomyopathies are a group of heterogeneous diseases that affect the muscles of the heart, leading to early morbidity and mortality in young and adults. Genetic forms of cardiomyopathy are caused predominantly by mutations in structural components of the cardiomyocyte sarcomeres, the contractile units of the heart, which includes cardiac Troponin T (TnT). Here, we generated mutations with CRISPR/Cas9 technology in the zebrafish tnnt2a gene, encoding cardiac TnT, at a mutational “hotspot” site to establish a zebrafish model for genetic cardiomyopathies. We found that a heterozygous tnnt2a mutation deleting Arginine at position 94 and Lysine at position 95 of TnT causes progressive cardiac structural changes resulting in heart failure. The cardiac remodeling is presented by an enlarged atrium, decreased ventricle size, increased myocardial stress as well as increased fibrosis. As early as five days post fertilization, larvae carrying the TnT RK94del mutation display diastolic dysfunction and impaired calcium dynamics related to increased Ca2+ sensitivity. In conclusion, adult zebrafish with a heterozygous TnT-RK94del mutation develop cardiomyopathy as seen in patients with TnT mutations and therefore represent a promising model to study disease mechanisms and to screen for putative therapeutic compounds.
Evaluation of the Analgesic Efficacy of a Bioelectronic Device in Non-Specific Chronic Low Back Pain with Neuropathic Component. A Randomized Trial
Authors: de Teresa Carlos , Varela-López Alfonso , Rios-Álvarez Susana , Gálvez Rafael , Maire Coralie , Gracia-Villar Santos , Battino Maurizio , Quiles José L.
Published: April 2021

Low energy pulsed electromagnetic signals (PEMS) therapy, in the field of bioelectronics, has been suggested as a promising analgesic therapy with special interest in treating conditions with poor response to pharmacotherapy. This study evaluated the effectiveness of PEMS therapy on the treatment of chronic low back pain patients with a neuropathic component. A group of 64 individuals with such condition was allocated to a 2-week treatment period (10 twenty-minute sessions on consecutive days) with an active PEMS therapy device or an inactive device in random order. The pain was assessed on a visual analog scale, and the functional status was assessed using the SF-12 questionnaire. The visual analog scale scores were lower after treatment than at baseline but only in the group treated with the active device. According to the DN4 score, neuropathic pain decreased in both experimental groups with respect to baseline, but this was only significant for the group treated with the active device. Similarly, an improvement in the SF-12 and Medical Outcomes Study (MOS) sleep scale components was reported. The study demonstrated that low-energy PEMS therapy was efficient in reducing pain and improving function in chronic low back pain patients with a neuropathic component.
Neurocognitive Status after Aortic Valve Replacement: Differences between TAVI and Surgery
Authors: Aroney Nicholas , Patterson Tiffany , Allen Christopher , Redwood Simon , Prendergast Bernard
Published: April 2021

Over the past decade, indications for transcatheter aortic valve implantation (TAVI) have progressed rapidly—procedural numbers now exceed those of surgical aortic valve replacement (SAVR) in many countries, and TAVI is now a realistic and attractive alternative to SAVR in low-risk patients. Neurocognitive outcomes after TAVI and SAVR remain an issue and sit firmly under the spotlight as TAVI moves into low-risk cohorts. Cognitive decline and stroke carry a significant burden and predict future functional decline, reduced mobility, poor quality of life and increased mortality. Early TAVI trials used varying neurocognitive definitions, and outcomes differed significantly as a result. Recent international consensus statements defining endpoints following TAVI and SAVR have standardised neurological outcomes and facilitate interpretation and comparison between trials. The latest TAVI and SAVR trials have demonstrated more consistent and favourable neurocognitive outcomes for TAVI patients, and cerebral embolic protection devices offer the prospect of further refinement and improvement.
Non-Invasive and Quantitative Estimation of Left Atrial Fibrosis Based on P Waves of the 12-Lead ECG—A Large-Scale Computational Study Covering Anatomical Variability
Authors: Nagel Claudia , Luongo Giorgio , Azzolin Luca , Schuler Steffen , Dössel Olaf , Loewe Axel
Published: April 2021

The arrhythmogenesis of atrial fibrillation is associated with the presence of fibrotic atrial tissue. Not only fibrosis but also physiological anatomical variability of the atria and the thorax reflect in altered morphology of the P wave in the 12-lead electrocardiogram (ECG). Distinguishing between the effects on the P wave induced by local atrial substrate changes and those caused by healthy anatomical variations is important to gauge the potential of the 12-lead ECG as a non-invasive and cost-effective tool for the early detection of fibrotic atrial cardiomyopathy to stratify atrial fibrillation propensity. In this work, we realized 54,000 combinations of different atria and thorax geometries from statistical shape models capturing anatomical variability in the general population. For each atrial model, 10 different volume fractions (0–45%) were defined as fibrotic. Electrophysiological simulations in sinus rhythm were conducted for each model combination and the respective 12-lead ECGs were computed. P wave features (duration, amplitude, dispersion, terminal force in V1) were extracted and compared between the healthy and the diseased model cohorts. All investigated feature values systematically in- or decreased with the left atrial volume fraction covered by fibrotic tissue, however value ranges overlapped between the healthy and the diseased cohort. Using all extracted P wave features as input values, the amount of the fibrotic left atrial volume fraction was estimated by a neural network with an absolute root mean square error of 8.78%. Our simulation results suggest that although all investigated P wave features highly vary for different anatomical properties, the combination of these features can contribute to non-invasively estimate the volume fraction of atrial fibrosis using ECG-based machine learning approaches.
Cardiovascular Disease in Type 1 Diabetes Mellitus: Epidemiology and Management of Cardiovascular Risk
Authors: Colom Cristina , Rull Anna , Sanchez-Quesada José Luis , Pérez Antonio
Published: April 2021

Cardiovascular disease (CVD) is a major cause of mortality in type 1 diabetes mellitus (T1DM) patients, and cardiovascular risk (CVR) remains high even in T1DM patients with good metabolic control. The underlying mechanisms remain poorly understood and known risk factors seem to operate differently in T1DM and type 2 diabetes mellitus (T2DM) patients. However, evidence of cardiovascular risk assessment and management in T1DM patients often is extrapolated from studies on T2DM patients or the general population. In this review, we examine the existing literature about the prevalence of clinical and subclinical CVD, as well as current knowledge about potential risk factors involved in the development and progression of atherosclerosis in T1DM patients. We also discuss current approaches to the stratification and therapeutic management of CVR in T1DM patients. Chronic hyperglycemia plays an important role, but it is likely that other potential factors are involved in increased atherosclerosis and CVD in T1DM patients. Evidence on the estimation of 10-year and lifetime risk of CVD, as well as the efficiency and age at which current cardiovascular medications should be initiated in young T1DM patients, is very limited and clearly insufficient to establish evidence-based therapeutic approaches to CVD management.
Increased Elasticity Modulus of Polymeric Materials Is a Source of Surface Alterations in the Human Body
Authors: Kapischke Matthias , Erlichman Igor , Pries Alexandra
Published: April 2021

The introduction of alloplastic materials (meshes) in hernia surgery has improved patient outcome by a radical reduction of hernia recurrence rate, but discussion about the biocompatibility of these implanted materials continues since observations of surface alterations of polypropylene and other alloplastic materials were published. This study intends to investigate if additives supplemented to alloplastic mesh materials merge into the solution and become analyzable. Four polypropylene and one polyester alloplastic material were incubated in different media for three weeks: distilled water, saline solution, urea solution, formalin, and hydrogen peroxide. No swelling or other changes were observed. Infrared spectroscopy scanning of incubated alloplastic materials and NMR studies of extracted solutions were performed to investigate loss of plasticizers. The surface of the mesh materials did not show any alterations independent of the incubation medium. FT-IR spectra before and after incubation did not show any differences. NMR spectra showed leaching of different plasticizers (PEG, sterically hindered phenols, thioester), of which there was more for polypropylene less for polyester. This could be the reason for the loss of elasticity of the alloplastic materials with consecutive physically induced surface alterations. A mixture of chemical reactions (oxidative stress with additive leaching from polymer fiber) in connection with physical alterations (increased elasticity modulus by loss of plasticizers) seem to be a source of these PP and PE alterations.
Deep Learning in Medical Image Analysis
Authors: Zhang Yudong , Gorriz Juan Manuel , Dong Zhengchao
Published: April 2021

Over recent years, deep learning (DL) has established itself as a powerful tool across a broad spectrum of domains in imaging—e [...]
Comparison of Direct and Adjoint k and α-Eigenfunctions
Authors: Vitali Vito , Chevallier Florent , Jinaphanh Alexis , Zoia Andrea , Blaise Patrick
Published: April 2021

Modal expansions based on k-eigenvalues and α-eigenvalues are commonly used in order to investigate the reactor behaviour, each with a distinct point of view: the former is related to fission generations, whereas the latter is related to time. Well-known Monte Carlo methods exist to compute the direct k or α fundamental eigenmodes, based on variants of the power iteration. The possibility of computing adjoint eigenfunctions in continuous-energy transport has been recently implemented and tested in the development version of TRIPOLI-4®, using a modified version of the Iterated Fission Probability (IFP) method for the adjoint α calculation. In this work we present a preliminary comparison of direct and adjoint k and α eigenmodes by Monte Carlo methods, for small deviations from criticality. When the reactor is exactly critical, i.e., for k0 = 1 or equivalently α0 = 0, the fundamental modes of both eigenfunction bases coincide, as expected on physical grounds. However, for non-critical systems the fundamental k and α eigenmodes show significant discrepancies.
Genome Sequence Analysis of the Oleaginous Yeast, Rhodotorula diobovata, and Comparison of the Carotenogenic and Oleaginous Pathway Genes and Gene Products with Other Oleaginous Yeasts
Authors: Fakankun Irene , Fristensky Brian , Levin David B.
Published: April 2021

Rhodotorula diobovata is an oleaginous and carotenogenic yeast, useful for diverse biotechnological applications. To understand the molecular basis of its potential applications, the genome was sequenced using the Illumina MiSeq and Ion Torrent platforms, assembled by AbySS, and annotated using the JGI annotation pipeline. The genome size, 21.1 MB, was similar to that of the biotechnological “workhorse”, R. toruloides. Comparative analyses of the R. diobovata genome sequence with those of other Rhodotorula species, Yarrowia lipolytica, Phaffia rhodozyma, Lipomyces starkeyi, and Sporidiobolus salmonicolor, were conducted, with emphasis on the carotenoid and neutral lipid biosynthesis pathways. Amino acid sequence alignments of key enzymes in the lipid biosynthesis pathway revealed why the activity of malic enzyme and ATP-citrate lyase may be ambiguous in Y. lipolytica and L. starkeyi. Phylogenetic analysis showed a close relationship between R. diobovata and R. graminis WP1. Dot-plot analysis of the coding sequences of the genes crtYB and ME1 corroborated sequence homologies between sequences from R. diobovata and R. graminis. There was, however, nonsequential alignment between crtYB CDS sequences from R. diobovata and those from X. dendrorhous. This research presents the first genome analysis of R. diobovata with a focus on its biotechnological potential as a lipid and carotenoid producer.
Gold against Asian Stock Markets during the COVID-19 Outbreak
Authors: Yousaf Imran , Bouri Elie , Ali Shoaib , Azoury Nehme
Published: April 2021

This study examines the safe-haven and hedging roles of gold against thirteen Asian stock markets during the COVID-19 outbreak. During the COVID-19 sub-period, gold is shown to be a strong hedge (diversifier) for the majority (minority) of Asian stock markets; it exhibits the property of a strong safe-haven in China, Indonesia, Singapore, and Vietnam, and a weak safe-haven in Pakistan and Thailand. The optimal weights of all stock-gold portfolios are lower during the COVID-19 sub-period than the pre COVID-19 sub-period, suggesting that portfolio investors should increase their investment in gold during the COVID-19 sub-period. The hedging effectiveness for most Asian stock markets is higher during the COVID-19 sub-period. Further analyses show that the hedge portfolio returns in many cases are mostly driven by gold implied volatility and inflation expectations in both sub-periods. Our findings have useful implications for market participants holding investments in Asian stocks during stressful periods.
Structural Failures Risk Analysis as a Tool Supporting Corporate Responsibility
Authors: Czajkowska Agnieszka , Ingaldi Manuela
Published: April 2021

The problem of the structural failures is inextricably linked with the construction industry. A structural failure can be defined as the unintentional, violent destruction of a building object or its part, as well as structural elements of scaffolding, forming elements, sheet piling and excavation linings. Structural failures always entail financial and environmental losses that cause a big problem for companies. The analysis of the structural failures allows to indicate the causes that led to them, but also to introduce actions to help avoid them or decrease their appearance in the future. From the point of view of sustainability risk, human life, corporate responsibility, but also possible financial penalties, it is a very important element of the business process management in an enterprise. In the paper the structural failures occurring in Poland in 2015–2019 were analyzed based on data from the General Office of Building Control (GUNB). They are divided into two categories: caused by random factors and resulting from human error. Failures caused by human error were divided into those related to construction, used material and building operation (exploitation). The structural failures occurring during construction works, e.g., construction, renovation, demolition works, as well as in existing facilities, e.g., during the use of the facility but also in facilities excluded from use, were analyzed. Then, the individual causes of the structural failures were analyzed in terms of repeatability in each category. The risk priority number was calculated for the causes in the group “random events” and nine causes related to “human error”. Actions aimed at reducing the risk of future failures were proposed. The results of the analysis provide conclusions that constitute input data for the improvement of both the processes themselves and the procedures for design, construction and exploitation, or methods and frequency of inspections.
The Northwest Passage in the Arctic: A Brief Assessment of the Relevant Marine Transportation System and Current Availability of Search and Rescue Services
Authors: Sheehan Rebecca , Dalaklis Dimitrios , Christodoulou Anastasia , Drewniak Megan , Raneri Peter , Dalaklis Angelos
Published: April 2021

The analysis in hand provides a brief assessment of the United States’ and Canada’s marine transportation system and relevant search and rescue (SAR) support in relation to the Northwest Passage, with the purpose of examining to what extent these countries’ relevant infrastructure resources are able to meet the expected growth of shipping operations and business activities in the Arctic. Through an extensive literature review, this assessment will specifically describe the most important influences upon the maritime transportation system, with the issue of certain geographical details and the capabilities of existing ports standing out. Additionally, vessel activity trends and vessel traffic routing measure initiatives will be examined. Furthermore, the SAR infrastructure details and means to render assistance to people in distress along the Northwest Passage will be discussed. The reality remains that port characteristics are limited and vessel traffic routing measure initiatives and upgrades to SAR assets are commendable but slow-paced. It is true that both the United States and Canada are taking proper measures to build up infrastructure needs, but they both may run out of time to put adequate infrastructure in place to deal effectively with the changing environment.
Thermoelectric Properties of Cu2Se Nano-Thin Film by Magnetron Sputtering
Authors: Yang Liangliang , Wei Jiangtao , Qin Yuanhao , Wei Lei , Song Peishuai , Zhang Mingliang , Yang Fuhua , Wang Xiaodong
Published: April 2021

Thermoelectric technology can achieve mutual conversion between thermoelectricity and has the unique advantages of quiet operation, zero emissions and long life, all of which can help overcome the energy crisis. However, the large-scale application of thermoelectric technology is limited by its lower thermoelectric performance factor (ZT). The thermoelectric performance factor is a function of the Seebeck coefficient, electrical conductivity, thermal conductivity and absolute temperature. Since these parameters are interdependent, increasing the ZT value has always been a challenge. Here, we report the growth of Cu2Se thin films with a thickness of around 100 nm by magnetron sputtering. XRD and TEM analysis shows that the film is low-temperature α-Cu2Se, XPS analysis shows that about 10% of the film’s surface is oxidized, and the ratio of copper to selenium is 2.26:1. In the range of 300–400 K, the maximum conductivity of the film is 4.55 × 105 S m−1, which is the maximum value reached by the current Cu2Se film. The corresponding Seebeck coefficient is between 15 and 30 µV K−1, and the maximum ZT value is 0.073. This work systematically studies the characterization of thin films and the measurement of thermoelectric properties and lays the foundation for further research on nano-thin-film thermoelectrics.
Annealing of Al-Zn-Mg-Cu Alloy at High Pressures: Evolution of Microstructure and the Corrosion Behavior
Authors: Suo Chuanjun , Ma Pan , Jia Yandong , Liu Xiao , Shi Xuerong , Yu Zhishui , Prashanth Konda Gokuldoss
Published: April 2021

Extruded Al-Zn-Mg-Cu alloy samples with grains aligned parallel to the extrusion direction were subjected to high-pressure annealing. The effects of annealing pressure on the microstructure, hardness, and corrosion properties (evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) were investigated. Phase analysis showed the presence of MgZn2 and α-Al phases, the MgZn2 phase dissolved into the matrix, and its amount decreased with the increasing annealing pressure. The recrystallization was inhibited, and the grains were refined, leading to an increase in the Vickers hardness with increasing the annealing pressure. The corrosion resistance was improved after high-pressure treatment, and a stable passivation layer was observed. Meanwhile, the number of corrosion pits and the width of corrosion cracks decreased in the high-pressure annealed samples.
Incorporation of Wheat Straw Ash as Partial Sand Replacement for Production of Eco-Friendly Concrete
Authors: Memon Shazim Ali , Javed Usman , Haris Muhammad , Khushnood Rao Arsalan , Kim Jong
Published: April 2021

The depletion of natural sand resources occurs due to excessive consumption of aggregate for concrete production. Continuous extraction of sand from riverbeds permanently depletes fine aggregate resources. At the same time, a major ecological challenge is the disposal of agricultural waste ash from biomass burning. In this study, an environmental friendly solution is proposed to investigate the incorporation of wheat straw ash (WSA) by replacing 0, 5, 10, 15, and 20% of sand in concrete. Characterization results of WSA revealed that it was well-graded, free from organic impurities, and characterized by perforated and highly porous tubules attributed to its porous morphology. A decrease in fresh concrete density and an increase in slump values were attained by an increase in WSA replacement percentage. An increasing trend in compressive strength, hardened concrete density, and ultrasonic pulse velocity was observed, while a decrease was noticed in the values of water absorption with the increase in WSA replacement percentages and the curing age. The WSA incorporation at all replacement percentages yielded concrete compressive strength values over 21 MPa, which complies with the minimum strength requirement of structural concrete as specified in ACI 318-19. Acid resistance of WSA incorporated concrete improved due to the formation of pozzolanic hydrates as evident in Chappelle activity and thermogravimetric analysis (TGA) results of WSA modified composites. Thus, the incorporation of WSA provides an environmentally friendly solution for its disposal. It helps in conserving natural aggregate resources by providing a suitable alternative to fine aggregate for the construction industry.
Multiple-Criteria Decision-Making and Sensitivity Analysis for Selection of Materials for Knee Implant Femoral Component
Authors: Kumar Raman , Dubey Rohit , Singh Sehijpal , Singh Sunpreet , Prakash Chander , Nirsanametla Yadaiah , Królczyk Grzegorz , Chudy Roman
Published: April 2021

Total knee replacement (TKR) is a remarkable achievement in biomedical science that enhances human life. However, human beings still suffer from knee-joint-related problems such as aseptic loosening caused by excessive wear between articular surfaces, stress-shielding of the bone by prosthesis, and soft tissue development in the interface of bone and implant due to inappropriate selection of TKR material. The choice of most suitable materials for the femoral component of TKR is a critical decision; therefore, in this research paper, a hybrid multiple-criteria decision-making (MCDM) tactic is applied using the degree of membership (DoM) technique with a varied system, using the weighted sum method (WSM), the weighted product method (WPM), the weighted aggregated sum product assessment method (WASPAS), an evaluation based on distance from average solution (EDAS), and a technique for order of preference by similarity to ideal solution (TOPSIS). The weights of importance are assigned to different criteria by the equal weights method (EWM). Furthermore, sensitivity analysis is conducted to check the solidity of the projected tactic. The weights of importance are varied using the entropy weights technique (EWT) and the standard deviation method (SDM). The projected hybrid MCDM methodology is simple, reliable and valuable for a conflicting decision-making environment.
Development of Precipitation-Strengthened Al0.8NbTiVM (M = Co, Ni) Light-Weight Refractory High-Entropy Alloys
Authors: Lee Kangjin , Jung Yunjong , Han Junhee , Hong Sung Hwan , Kim Ki Buem , Liaw Peter K. , Lee Chanho , Song Gian
Published: April 2021

Single-phase solid-solution refractory high-entropy alloys (RHEAs) have been receiving significant attention due to their excellent mechanical properties and phase stability at elevated temperatures. Recently, many studies have been reported regarding the precipitation-enhanced alloy design strategy to further improve the mechanical properties of RHEAs at elevated temperatures. In this study, we attempted to develop precipitation-hardened light-weight RHEAs via addition of Ni or Co into Al0.8NbTiV HEA. The added elements were selected due to their smaller atomic radius and larger mixing enthalpy, which is known to stimulate the formation of precipitates. The addition of the Ni or Co leads to the formation of the sigma precipitates with homogeneous distribution. The formation and homogeneous distribution of sigma particles plays a critical role in improvement of yield strength. Furthermore, the Al0.8NbTiVM0.2 (M = Co, Ni) HEAs show excellent specific yield strength compared to single-phase AlNbTiV and NbTiVZr RHEA alloys and conventional Ni-based superalloy (Inconel 718) at elevated temperatures.
Long-Term Converse Magnetoelectric Response of Actuated 1-3 Multiferroic Composite Structures
Authors: Stampfli Ryan , Huynh Nha Uyen , Youssef George
Published: April 2021

Multiferroic composite materials operating under the principle of strain mediation across the interfaces separating different material boundaries address many limitations of single-phase magnetoelectric materials. Although significant research has been conducted to explore their responses relating to the topography and directionality of material polarization and magnetic loading, there remain unanswered questions regarding the long-term performance of these multiferroic structures. In this study, a multiferroic composite structure consisting of an inner Terfenol-D magnetostrictive cylinder and an outer lead zirconate titanate (PZT) piezoelectric cylinder was investigated. The composite was loaded over a 45-day period with an AC electric field (20 kV/m) at a near-resonant frequency (32.5 kHz) and a simultaneously applied DC magnetic field of 500 Oe. The long-term magnetoelectric and thermal responses were continuously monitored, and an extensive micrographic analysis of pretest and post-test states was performed using scanning electron microscopy (SEM). The extended characterization revealed a significant degradation of ≈30–50% of the magnetoelectric response, whereas SEM micrographs indicated a reduction in the bonding interface quality. The increase in temperature at the onset of loading was associated with the induced oscillatory piezoelectric strain and accounted for 28% of the strain energy loss over nearly one hour.
Stability of Systems of Fractional-Order Differential Equations with Caputo Derivatives
Authors: Brandibur Oana , Garrappa Roberto , Kaslik Eva
Published: April 2021

Systems of fractional-order differential equations present stability properties which differ in a substantial way from those of systems of integer order. In this paper, a detailed analysis of the stability of linear systems of fractional differential equations with Caputo derivative is proposed. Starting from the well-known Matignon’s results on stability of single-order systems, for which a different proof is provided together with a clarification of a limit case, the investigation is moved towards multi-order systems as well. Due to the key role of the Mittag–Leffler function played in representing the solution of linear systems of FDEs, a detailed analysis of the asymptotic behavior of this function and of its derivatives is also proposed. Some numerical experiments are presented to illustrate the main results.
The Barriers and Facilitators of Different Stakeholders When Deprescribing Benzodiazepine Receptor Agonists in Older Patients—A Systematic Review
Authors: Rasmussen Anja Fog , Poulsen Sarah Sonne , Oldenburg Lykke Ida Kaas , Vermehren Charlotte
Published: April 2021

Treatment of older patients with benzodiazepines and Z-drugs (BZRA) is associated with an increased risk of side effects. However, this treatment is still used among these patients. Deprescribing can be a tool to reduce inappropriate medication. This review aims to identify and compare barriers and facilitators of stakeholders involved in BZRA deprescribing in older patients and uncover potential gaps in the research field. The search was conducted in PubMed, EMBASE, PsycINFO, and Cochrane Library. Ten articles based on qualitative data on BZRA deprescribing in older patients (≥65 years) published between 2005–2020 were included. Six articles referred to patients as stakeholders, two referred to physicians, and one to nurses and caregivers, respectively, indicating a need for more studies in the field. More barriers than facilitators were identified. Important findings were the patient willingness to deprescribe BZRA compared to physicians, who did not mention deprescribing to patients due to barriers such as expected patient resistance. Nurses mentioned barriers like lack of knowledge and the feeling that their options were not valued by physicians; education was found to be a shared deprescribing facilitator among the stakeholders. Being aware of deprescribing barriers and facilitators can be helpful in future successful deprescribing interventions.
Tethered and Untethered 3D Microactuators Fabricated by Two-Photon Polymerization: A Review
Authors: Lao Zhaoxin , Xia Neng , Wang Shijie , Xu Tiantian , Wu Xinyu , Zhang Li
Published: April 2021

Microactuators, which can transform external stimuli into mechanical motion at microscale, have attracted extensive attention because they can be used to construct microelectromechanical systems (MEMS) and/or microrobots, resulting in extensive applications in a large number of fields such as noninvasive surgery, targeted delivery, and biomedical machines. In contrast to classical 2D MEMS devices, 3D microactuators provide a new platform for the research of stimuli-responsive functional devices. However, traditional planar processing techniques based on photolithography are inadequate in the construction of 3D microstructures. To solve this issue, researchers have proposed many strategies, among which 3D laser printing is becoming a prospective technique to create smart devices at the microscale because of its versatility, adjustability, and flexibility. Here, we review the recent progress in stimulus-responsive 3D microactuators fabricated with 3D laser printing depending on different stimuli. Then, an outlook of the design, fabrication, control, and applications of 3D laser-printed microactuators is propounded with the goal of providing a reference for related research.
Comparing Sediment Microbiomes in Contaminated and Pristine Wetlands along the Coast of Yucatan
Authors: Navarrete-Euan Herón , Rodríguez-Escamilla Zuemy , Pérez-Rueda Ernesto , Escalante-Herrera Karla , Martínez-Núñez Mario Alberto
Published: April 2021

Microbial communities are important players in coastal sediments for the functioning of the ecosystem and the regulation of biogeochemical cycles. They also have great potential as indicators of environmental perturbations. To assess how microbial communities can change their composition and abundance along coastal areas, we analyzed the composition of the microbiome of four locations of the Yucatan Peninsula using 16S rRNA gene amplicon sequencing. To this end, sediment from two conserved (El Palmar and Bocas de Dzilam) and two contaminated locations (Sisal and Progreso) from the coast northwest of the Yucatan Peninsula in three different years, 2017, 2018 and 2019, were sampled and sequenced. Microbial communities were found to be significantly different between the locations. The most noticeable difference was the greater relative abundance of Planctomycetes present at the conserved locations, versus FBP group found with greater abundance in contaminated locations. In addition to the difference in taxonomic groups composition, there is a variation in evenness, which results in the samples of Bocas de Dzilam and Progreso being grouped separately from those obtained in El Palmar and Sisal. We also carry out the functional prediction of the metabolic capacities of the microbial communities analyzed, identifying differences in their functional profiles. Our results indicate that landscape of the coastal microbiome of Yucatan sediment shows changes along the coastline, reflecting the constant dynamics of coastal environments and their impact on microbial diversity.