bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Genetic Polymorphisms on Response to Biologics in Moderate-to-Severe Psoriasis
Authors: Membrive Jiménez Cristina , Pérez Ramírez Cristina , Sánchez Martín Almudena , Vieira Maroun Sayleth , Arias Santiago Salvador Antonio , Ramírez Tortosa María del Carmen , Jiménez Morales Alberto
Published: April 2021

Psoriasis is a chronic inflammatory skin pathology of autoimmune origin and unknown etiology. There are various therapies for treating it, including a wide range of biopharmaceuticals indicated in moderate-to-severe psoriasis. Depending on their therapeutic target, they are classified as tumor necrosis factor inhibitors (anti-TNF) or cytokine inhibitors (interleukin-12, 23, and 17 antagonists). Although they have proved effective and safe, in clinical practice, many patients show a short- and long-term suboptimal response and even varying degrees of toxicity. This variability in response may be influenced by genetic factors, such as polymorphisms in the genes involved in the pathological environment, metabolism or mechanism of action of the drug that could affect the effectiveness and toxicity of biological therapies. This review assesses pharmacogenetic studies of the impact of genetic factors on response to biopharmaceuticals and toxicity in patients diagnosed with moderate-to-severe psoriasis. The results suggest that polymorphisms detected in the HLA genes, in genes that encode cytokines (TNF, IL genes, TNFAIP3), transporters (PDE3A-SLCO1C1, SLC12A8), receptors (TNFRSF1B, CD84, FCGR2A and FCGR3A, IL17RA, IL23R, TLR genes, PGLYRP4) and associated proteins (TNFAIP3, LY96, TIRAP, FBXL19), as well as other genes implicated in the pathogenesis of psoriasis (CDKAL1, CARD14, PTTG1, MAP3K1, ZNF816A, GBP6, CTNNA2, HTR2A, CTLA4, TAP1) can be used in the future as predictive markers of treatment response and/or toxicity with biological therapies in patients diagnosed with moderate-to-severe psoriasis, tailoring treatment to the individual patient.
Gut Microbiome in a Russian Cohort of Pre- and Post-Cholecystectomy Female Patients
Authors: Grigor’eva Irina , Romanova Tatiana , Naumova Natalia , Alikina Tatiana , Kuznetsov Alexey , Kabilov Marsel
Published: April 2021

The last decade saw extensive studies of the human gut microbiome and its relationship to specific diseases, including gallstone disease (GSD). The information about the gut microbiome in GSD-afflicted Russian patients is scarce, despite the increasing GSD incidence worldwide. Although the gut microbiota was described in some GSD cohorts, little is known regarding the gut microbiome before and after cholecystectomy (CCE). By using Illumina MiSeq sequencing of 16S rRNA gene amplicons, we inventoried the fecal bacteriobiome composition and structure in GSD-afflicted females, seeking to reveal associations with age, BMI and some blood biochemistry. Overall, 11 bacterial phyla were identified, containing 916 operational taxonomic units (OTUs). The fecal bacteriobiome was dominated by Firmicutes (66% relative abundance), followed by Bacteroidetes (19%), Actinobacteria (8%) and Proteobacteria (4%) phyla. Most (97%) of the OTUs were minor or rare species with ≤1% relative abundance. Prevotella and Enterocossus were linked to blood bilirubin. Some taxa had differential pre- and post-CCE abundance, despite the very short time (1–3 days) elapsed after CCE. The detailed description of the bacteriobiome in pre-CCE female patients suggests bacterial foci for further research to elucidate the gut microbiota and GSD relationship and has potentially important biological and medical implications regarding gut bacteria involvement in the increased GSD incidence rate in females.
Multi-Factorized Semi-Covariance of Stock Markets and Gold Price
Authors: Shi Yun , Yang Lin , Huang Mei , Huang Jun
Published: April 2021

Complex models have received significant interest in recent years and are being increasingly used to explain the stochastic phenomenon with upward and downward fluctuation such as the stock market. Different from existing semi-variance methods in traditional integer dimension construction for two variables, this paper proposes a simplified multi-factorized fractional dimension derivation with the exact Excel tool algorithm involving the fractional center moment extension to covariance, which is a complex parameter average that is a multi-factorized extension to Pearson covariance. By examining the peaks and troughs of gold price averages, the proposed algorithm provides more insight into revealing underlying stock market trends to see who is the financial market leader during good economic times. The calculation results demonstrate that the complex covariance is able to distinguish subtle differences among stock market performances and gold prices for the same field that the two variable covariance may overlook. We take London, Tokyo, Shanghai, Toronto, and Nasdaq as the representative examples.
Impact of Audit Committee Quality on the Financial Performance of Conventional and Islamic Banks
Authors: Haddad Achraf , El Ammari Anis , Bouri Abdelfattah
Published: April 2021

A lot of previous research studied the relationship between audit committee quality and the financial performance of conventional banks before and during the subprime crisis, whereas some other investigations analyzed the same association in the framework of Islamic banks. However, no study has compared these two correlations either before, during, or after the subprime crisis. Several reasons explain the differences, such as the audit committee quality of each bank type, the evaluation method of the financial performance, the research peculiarities, the methodology, the data, and the interpretation. This research aims to compare the impacts of the audit committees’ quality on the financial performance of Islamic and conventional banks between 2010 and 2019. The financial performance measures and audit committees’ determinants of the conventional and Islamic banks concerned 112 banks of each type. The collected data covered four continents: America, Asia, Africa, and Europe. Impacts were compared by using the Generalized Least Squares analysis. The results showed that the audit committee reduced the profitability of two bank types. Moreover, it harmed the conventional banks’ efficiency but reported an unclear effect within Islamic banks. Even so, we noticed that the audit committee had a positive impact on the conventional banks’ liquidity, while the same effect was apparently ambiguous for the Islamic banks’ liquidity. For solvency, the audit committee positively influenced conventional banks while it affected that of Islamic banks.
Relative Stock Market Performance during the Coronavirus Pandemic: Virus vs. Policy Effects in 80 Countries
Authors: Burdekin Richard C. K. , Harrison Samuel
Published: April 2021

This paper examines relative stock market performance following the onset of the coronavirus pandemic for a sample of 80 stock markets. Weekly data on coronavirus cases and deaths are employed alongside Oxford indices on each nation’s stringency and government support intensity. The results are broken down both by month and by geographical region. The full sample results show that increased coronavirus cases exert the expected overall effect of worsening relative stock market performance, but with little consistent impact of rising deaths. There is some evidence of significantly negative stock market effects arising from lockdowns as reflected in the Oxford stringency index. There are also positive reactions to government support in March and December in the overall sample—combined with some additional pervasive effects seen in mid-2020 in Latin America.
Modeling Integrated Impacts of Climate Change and Grazing on Mongolia’s Rangelands
Authors: Kowal Virginia , Ahlborn Julian , Jamsranjav Chantsallkham , Avirmed Otgonsuren , Chaplin-Kramer Rebecca
Published: April 2021

Mongolia contains some of the largest intact grasslands in the world, but is vulnerable to future changes in climate and continued increases in the number of domestic livestock. As these are two major drivers of change, it is important to understand interactions between the impact of climate and grazing on productivity of Mongolia’s rangelands and the livelihoods they sustain. We use a gridded, spatially explicit model, the Rangeland Production Model (RPM), to explore the simultaneous and interacting effects of climate and management changes on Mongolia’s rangeland and future livestock production. Comparing the relative impact of temperature, precipitation, and grazing intensity, varied individually and in combination, we find that climatic factors dominate impacts on forage biomass and animal diet sufficiency. Site rainfall strongly mediates the impact of grazing on standing biomass, such that more productive or higher-rainfall sites are more vulnerable to increases in grazing pressure. Gridded simulations covering Mongolia’s Gobi-Steppe ecoregion show that while rangeland biomass is generally predicted to increase under future climate conditions, interactions among spatially varying drivers create strong heterogeneity in the magnitude of change.
Spatio-Temporal Coupling Characteristics and the Driving Mechanism of Population-Land-Industry Urbanization in the Yangtze River Economic Belt
Authors: Huang Liejia , Yang Peng , Zhang Boqing , Hu Weiyan
Published: April 2021

The purpose of this paper is to probe into the coupled coordination of urbanization in population, land, and industry to improve urbanization quality. A coupled coordination degree model, spatial analysis method and spatial metering model are employed. The study area is 110 prefecture-level cities in the Yangtze River Economic Belt. The study shows that: (1) the coupling degree of the population-land-industry urbanization grew very slowly between 2006 and 2016. On the whole, the three-dimensional urbanization is in a running-in period, and land-based urbanization dominates, while population-based urbanization and industry-based urbanization are relatively lagging behind. (2) The three major urban agglomerations, the Chengdu-Chongqing, the middle reaches of the Yangtze River and the Yangtze River Delta, are parallel to the whole area in terms of the coupling degree of the three dimensional urbanization with a well-ordered structure, especially in the central cities of the three major urban agglomerations. (3) There is significant spatial correlation in the coupling degree and coordination degree of the three-dimensional urbanization. The high value of coupling degree and coordination degree are clustered continuously in developed cities, provincial capitals, and central cities of the downstream reaches of the Yangtze River. (4) The coordinated degree has significant positive spatial autocorrelation, showing obvious spatial agglomeration characteristics: H-H agglomeration areas are concentrated in the downstream developed areas such as Jiangsu, Zhejiang, and Shanghai. L-L agglomeration areas are mainly concentrated in upstream undeveloped areas, but the number of their cities shows a decreasing trend. (5) The coordination degree of the three-dimensional urbanization is the result of the comprehensive effect of economic development level, the government’s decision-making behavior, and urban location. Among them, the economic development level, urbanization investment, traffic condition, and urban geographical location play a decisive role. This paper contributes to the existing literatures by exploring urbanization quality, spatial correlation and influencing factors from the perspectives of the three-dimensional urbanization in the Yangtze River Economic Belt. The conclusion might be helpful to promote the coupling and coordinated development of urbanization in population-land-industry, and ultimately to improve urbanization quality in the Yangtze River Economic Belt.
The Importance of Network Position in the Diffusion of Agricultural Innovations in Smallholders of Dual-Purpose Cattle in Mexico
Authors: Oriana Villarroel-Molina , Carmen De-Pablos-Heredero , Cecilio Barba , Jaime Rangel , Antón García
Published: April 2021

The dual-purpose bovine production system (DP) is the most widespread small-scale model in Latin American tropics, where it constitutes a key tool in terms of food security. Most DPs are subsistence farms oriented to self-consumption, with a very low technology adoption rate. Hence, the main challenge is how to improve the technological level without compromising the system sustainability by applying land-sharing practices. Thus, through networks methodology, this paper analysed how farmers adopt reproductive technologies. The sample consisted of 383 very small farms of dual-purpose cattle. Seven reproduction technologies oriented to improve reproductive efficiency were evaluated: Breeding soundness evaluation in bulls, semen fertility evaluation, evaluation of female body condition, oestrus detection, pregnancy diagnosis, seasonal or continuous mating, and breeding policy. Social Network Analysis (SNA) allowed identifying adoption patterns, as the joint adoption of semen fertility evaluation, estrus detection, and pregnancy diagnosis, which were consider complementary technologies. Similarly, breeding soundness evaluation in bulls was found to be the most widely adopted technology. The results showed that these farmers presented a very low level of reproduction technology adoption rate and suggested that farmer’s affiliation with organizations such as the Livestock Groups for Technological Validation and Transfer (GGAVATT), and its network position had a significant impact on the level of technological adoption. In the first stage of adoption, this work highlighted the importance of centralized models from the GGAVATT to the farmers, related to the knowledge and absorption dynamic capabilities. In a later stage, decentralized models through technological leaders are a priority, related to integration and innovation dynamic capabilities.
Landslide Susceptibility Mapping of Central and Western Greece, Combining NGI and WoE Methods, with Remote Sensing and Ground Truth Data
Authors: Kontoes Charalampos , Loupasakis Constantinos , Papoutsis Ioannis , Alatza Stavroula , Poyiadji Eleftheria , Ganas Athanassios , Psychogyiou Christina , Kaskara Mariza , Antoniadi Sylvia , Spanou Natalia
Published: April 2021

The exploitation of remote sensing techniques has substantially improved pre- and post- disaster landslide management over the last decade. A variety of landslide susceptibility methods exists, with capabilities and limitations related to scale and spatial accuracy issues, as well as data availability. The Interferometric Synthetic Aperture Radar (InSAR) capabilities have significantly contributed to the detection, monitoring, and mapping of landslide phenomena. The present study aims to point out the contribution of InSAR data in landslide detection and to evaluate two different scale landslide models by comparing a heuristic to a statistical method for the rainfall-induced landslide hazard assessment. Aiming to include areas with both high and low landslide occurrence frequencies, the study area covers a large part of the Aetolia–Acarnania and Evritania prefectures, Central and Western Greece. The landslide susceptibility product provided from the weights of evidence (WoE) method proved more accurate, benefitting from the expert opinion and the landslide inventory. On the other hand, the Norwegian Geological Institute (NGI) methodology has the edge on its immediate implementation, with minimum data requirements. Finally, it was proved that using sequential SAR image acquisitions gives the benefit of an updated landslide inventory, resulting in the generation of, on request, updated landslide susceptibility maps.
Endovascular Treatment of Intracranial Aneurysms
Authors: Adamou Antonis , Alexandrou Maria , Roth Christian , Chatziioannou Achilles , Papanagiotou Panagiotis
Published: April 2021

Traditionally, surgical clipping was the only available treatment modality for intracranial aneurysms. However, in the last few decades, the endovascular therapy of intracranial aneurysms (IAs) has seen a tremendous evolution and development. From coiling to flow diversion and flow disruptor devices, endovascular treatment modalities have increased in number and received broader indications throughout the years. In this review article, the treatment modalities for the endovascular management of IAs are presented, emphasizing newer devices and technologies.
Comparison of Androgen Receptor, VEGF, HIF-1, Ki67 and MMP9 Expression between Non-Metastatic and Metastatic Stages in Stromal and Tumor Cells of Oral Squamous Cell Carcinoma
Authors: Batelja-Vuletic Lovorka , Tomasovic-Loncaric Cedna , Ceppi Marcello , Bruzzone Marco , Fucic Aleksandra , Krstanac Karolina , Boras Vucicevic Vanja
Published: April 2021

Objectives: Oral squamous cell carcinoma (OSCC) is the most common oral malignancy with low survival as it is very often diagnosed at an advanced stage, which is why the accurate profiling of the tumor is essential. The aim of this study was to, for the first time, compare in OSCC the frequency of AR, VEGF, MMP9, HiF1beta and Ki67 between the non-metastatic and metastatic disease. Materials and Methods: In the study, 96 non-metastatic and 91 metastatic OSCC patients were analysed for AR, VEGF, MMP9, HiF1beta and Ki67 levels by immunohistochemistry. Results: All of the tested biomarkers significantly differed between non-metastatic and metastatic disease. A significant association was found between >/=20% AR positive epithelium cells in cytoplasm, Ki67 and VEGF in cancer stroma. Ki67, HiF1beta, VEGF and MMP9 were significantly associated with TNM stages. Conclusion: Our results show for the first time an interplay between AR, VEGF, MMP9, HiF1beta and Ki67 in OSCC which may contribute to better diagnostics and therapy selection.
Generation of Antibodies against Foot-and-Mouth-Disease Virus Capsid Protein VP4 Using Hepatitis B Core VLPs as a Scaffold
Authors: Swanson Jessica , Fragkoudis Rennos , Hawes Philippa C. , Newman Joseph , Burman Alison , Panjwani Anusha , Stonehouse Nicola J. , Tuthill Tobias J.
Published: April 2021

The picornavirus foot-and-mouth disease virus (FMDV) is the causative agent of the economically important disease of livestock, foot-and-mouth disease (FMD). VP4 is a highly conserved capsid protein, which is important during virus entry. Previous published work has shown that antibodies targeting the N-terminus of VP4 of the picornavirus human rhinovirus are broadly neutralising. In addition, previous studies showed that immunisation with the N-terminal 20 amino acids of enterovirus A71 VP4 displayed on the hepatitis B core (HBc) virus-like particles (VLP) can induce cross-genotype neutralisation. To investigate if a similar neutralising response against FMDV VP4 could be generated, HBc VLPs displaying the N-terminus of FMDV VP4 were designed. The N-terminal 15 amino acids of FMDV VP4 was inserted into the major immunodominant region. HBc VLPs were also decorated with peptides of the N-terminus of FMDV VP4 attached using a HBc-spike binding tag. Both types of VLPs were used to immunise mice and the resulting serum was investigated for VP4-specific antibodies. The VLP with VP4 inserted into the spike, induced VP4-specific antibodies, however the VLPs with peptides attached to the spikes did not. The VP4-specific antibodies could recognise native FMDV, but virus neutralisation was not demonstrated. This work shows that the HBc VLP presents a useful tool for the presentation of FMDV capsid epitopes.
Cross-Validation of Next-Generation Sequencing Technologies for Diagnosis of Chromosomal Mosaicism and Segmental Aneuploidies in Preimplantation Embryos Model
Authors: Biricik Anil , Cotroneo Ettore , Minasi Maria Giulia , Greco Pier Francesco , Bono Sara , Surdo Matteo , Lecciso Federica , Sessa Mariateresa , Fiorentino Francesco , Spinella Francesca , Greco Ermanno
Published: April 2021

Detection of mosaic embryos is crucial to offer more possibilities of success to women undergoing in vitro fertilization (IVF) treatment. Next Generation Sequencing (NGS)-based preimplantation genetic testing are increasingly used for this purpose since their higher capability to detect chromosomal mosaicism in human embryos. In the recent years, new NGS systems were released, however their performance for chromosomal mosaicism are variable. We performed a cross-validation analysis of two different NGS platforms in order to assess the feasibility of these techniques and provide standard parameters for the detection of such aneuploidies. The study evaluated the performance of MiseqTM Veriseq (Illumina, San Diego, CA, USA) and Ion Torrent Personal Genome Machine PGMTM ReproSeq (Thermo Fisher, Waltham, MA, USA) for the detection of whole and segmental mosaic aneuploidies. Reconstructed samples with known percentage of mosaicism were analyzed with both platforms and sensitivity and specificity were determined. Both platforms had high level of specificity and sensitivity with a Limit Of Detection (LOD) at ≥30% of mosaicism and a showed a ≥5.0 Mb resolution for segmental abnormalities. Our findings demonstrated that NGS methodologies are capable of accurately detecting chromosomal mosaicism and segmental aneuploidies. The knowledge of LOD for each NGS platform has the potential to reduce false-negative and false-positive diagnoses when applied to detect chromosomal mosaicism in a clinical setting.
Thermosensitive Drug Delivery System SBA-15-PEI for Controlled Release of Nonsteroidal Anti-Inflammatory Drug Diclofenac Sodium Salt: A Comparative Study
Authors: Zauska Lubos , Bova Stefan , Benova Eva , Bednarcik Jozef , Balaz Matej , Zelenak Vladimir , Hornebecq Virginie , Almasi Miroslav
Published: April 2021

Mesoporous SBA-15 silica material was prepared by the sol–gel method and functionalized with thermosensitive polyethylenimine polymers with different molecular weight (g·mol−1): 800 (SBA-15(C)-800), 1300 (SBA-15(C)-1300) and 2000 (SBA-15(C)-2000). The nonsteroidal anti-inflammatory drug (NSAID) diclofenac sodium was selected as a model drug and encapsulated into the pores of prepared supports. Materials were characterized by the combination of infrared spectroscopy (IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), photon cross-correlation spectroscopy (PCCS), nitrogen adsorption/desorption analysis, thermogravimetry (TG), differential scanning calorimetry (DSC) and small-angle X-ray diffraction (SA-XRD) experiments. The drug release from prepared matrixes was realized in two model media differing in pH, namely small intestine environment/simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2), and at different temperatures, namely normal body temperature (T = 37 °C) and inflammatory temperature (T = 42 °C). The process of drug loading into the pores of prepared materials from the diclofenac sodium salt solutions with different concentrations and subsequent quantitative determination of released drugs was analyzed by UV-VIS spectroscopy. Analysis of prepared SBA-15 materials modified with polyethylenimines in solution showed a high ability to store large amounts of the drug, up to 230 wt.%. Experimental results showed their high drug release into the solution at pH = 7.4 for both temperatures, which is related to the high solubility of diclofenac sodium in a slightly alkaline environment. At pH = 2, a difference in drug release rate was observed between both temperatures. Indeed, at a higher temperature, the release rates and the amount of released drug were 2–3 times higher than those observed at a lower temperature. Different kinetic models were used to fit the obtained drug release data to determine the drug release rate and its release mechanism. Moreover, the drug release properties of prepared compounds were compared to a commercially available medicament under the same experimental conditions.
Natural Fibres as a Sustainable Reinforcement Constituent in Aligned Discontinuous Polymer Composites Produced by the HiPerDiF Method
Authors: Kandemir Ali , Longana Marco L. , Panzera Tulio H. , del Pino Gilberto G. , Hamerton Ian , Eichhorn Stephen J.
Published: April 2021

Sustainable fibre reinforced polymer composites have drawn significant attention in many industrial sectors as a means for overcoming issues with end-of-life regulations and other environmental concerns. Plant based natural fibres are considered to be the most suitable reinforcement for sustainable composites since they are typically from renewable resources, are cheap, and are biodegradable. In this study, a number of plant based natural fibres-curaua, flax, and jute fibres-are used to reinforce epoxy, poly(lactic acid) (PLA), and polypropylene (PP) matrices to form aligned discontinuous natural fibre reinforced composites (ADNFRC). The novel HiPerDiF (high performance discontinuous fibre) method is used to produce high performance ADNFRC. The tensile mechanical, fracture, and physical (density, porosity, water absorption, and fibre volume fraction) properties of these composites are reported. In terms of stiffness, epoxy and PP ADNFRC exhibit similar properties, but epoxy ADNFRC shows increased strength compared to PP ADNFRC. It was found that PLA ADNFRC had the poorest mechanical performance of the composites tested, due principally to the limits of the polymer matrix. Moreover, curaua, flax (French origin), and jute fibres are found to be promising reinforcements owing to their mechanical performance in epoxy and PP ADNFRC. However, only flax fibre with desirable fibre length is considered to be the best reinforcement constituent for future sustainable ADNFRC studies in terms of mechanical performance and current availability on the market, particularly for the UK and EU.
Influence of Polypropylene, Glass and Steel Fiber on the Thermal Properties of Concrete
Authors: Małek Marcin , Jackowski Mateusz , Łasica Waldemar , Kadela Marta
Published: April 2021

The variety of approaches to tackle climate change reflects the size of this global problem. No technology will act as a panacea to cure the greenhouse gas emissions problem, but new building materials with byproducts or even wastes have the potential to play a major role in reducing the environmental impacts of the building sector. In this study, three potential solutions of concrete with dispersed reinforcement in the form of recycled fibers (polypropylene, glass and steel) were examined. The aim is to present a detailed analysis of the thermal properties of new building materials in an experimental approach. Concrete mixtures were prepared according to a new, laboratory-calculated recipe containing granite aggregate, a polycarboxylate-based deflocculant, Portland cement (52.5 MPa) and fibers. This experimental work involved three different contents of each fiber (0.5%, 0.75% and 1.0 wt.%), and all tests were carried after the complete curing cycle of concrete (28 days).
Essential Material Knowledge and Recent Model Developments for REBCO-Coated Conductors in Electric Power Systems
Authors: Trillaud Frederic , dos Santos Gabriel , Gonçalves Sotelo Guilherme
Published: April 2021

The manufacturing of commercial REBCO tapes, REBCO referring to Rare-earth barium copper oxide, has matured enough to lead to a variety of applications ranging from scientific instruments to electric power systems. In particular, its large current density with a high n index and low hysteresis losses make it a strong candidate for specific applications relying on the dependence of its resistance on current. Despite its advantages, there are still issues that remain to be addressed, such as the scarcity of experimental data for the basic characteristics of the superconductor over a wide range of temperature and applied magnetic field, the inhomogeneity of these characteristics along the conductor length, as well as the anisotropy of the critical current and n index with respect to the direction of the applied magnetic field. To better utilize the technology, it is therefore sensible to understand the relevancy of these issues so that one could simulate as accurately as possible the physics of the superconductor, at least the dynamics that may impact the correct operation of the superconducting device. There are different levels of modelling to achieve such a goal that can either focus on the performance of the superconductor itself, or on the whole device. The present work addresses some of the latest developments in the modelling of commercial REBCO tapes in power systems with a particular focus on the thermoelectric behavior of superconducting devices connected to external circuits. Two very different approaches corresponding to two different scales in the modelling of superconducting devices are presented: (1) analysis using equivalent models and lumped parameters to study the thermoelectric response of superconducting devices as a whole, (2) Finite Element Analysis (FEA) to compute distributed fields such as current density, magnetic flux density and local losses in tapes. In this context, this paper reviews both approaches and gives a broad variety of examples to show their practical applications in electric power systems. Firstly, they show the relevance of the technology in power systems engineering. Secondly, they allow inferring the necessary level of model details to optimize the operation of superconducting power devices in power grids. This level of details relies completely on the knowledge of some basic measurable properties of superconducting tapes (critical current and n index) and their cooling conditions.
Simulation of Leather Visco-Elastic Behavior Based on Collagen Fiber-Bundle Properties and a Meso-Structure Network Model
Authors: Dietrich Sascha , Lykhachova Olga , Cheng Xiaoyin , Godehardt Michael , Kronenberger Markus , Meyer Michael , Neusius David , Orlik Julia , Schladitz Katja , Schulz Haiko , Steiner Konrad , Voigt Diana
Published: April 2021

Simulation-based prediction of mechanical properties is highly desirable for optimal choice and treatment of leather. Nowadays, this is state-of-the-art for many man-made materials. For the natural material leather, this task is however much more demanding due to the leather’s high variability and its extremely intricate structure. Here, essential geometric features of the leather’s meso-scale are derived from 3D images obtained by micro-computed tomography and subsumed in a parameterizable structural model. That is, the fiber-bundle structure is modeled. The structure model is combined with bundle properties derived from tensile tests. Then the effective leather visco-elastic properties are simulated numerically in the finite element representation of the bundle structure model with sliding contacts between bundles. The simulation results are validated experimentally for two animal types, several tanning procedures, and varying sample positions within the hide. Finally, a complete workflow for assessing leather quality by multi-scale simulation of elastic and visco-elastic properties is established and validated.
Physical Properties and Durability of Lime-Cement Mortars Prepared with Water Containing Micro-Nano Bubbles of Various Gases
Authors: Grzegorczyk-Frańczak Małgorzata , Barnat-Hunek Danuta , Andrzejuk Wojciech , Zaburko Jacek , Zalewska Monika , Łagód Grzegorz
Published: April 2021

The paper presents the experimental studies on the effect of the water containing micro-nano bubbles of various gases on the physico-mechanical properties of lime-cement mortars. In total, 7 types of mortars were prepared: with water containing the micro-nano bubbles of O2, O3 or CO2 as 50% or 100% substitute of ordinary mixing water (tap water) and the reference mortar prepared using tap water. In order to determine the influence of water with micro-nano bubbles of gases, the consistency of fresh mortar and the physical properties of hardened mortar, i.e., specific and apparent density, total porosity, water absorption by weight and capillary absorption, were established. The mechanical strength of the considered mortars was studied as well by conducting the tests for flexural and compressive strengths following 14, 28 and 56 days. Reduced workability and capillary absorption were observed in the modified mortars within the range of 0.9–8.5%. The mortars indicated an increase in the flexural strength after 28 days ranging from 3.4% to 23.5% and improved compressive strength in 1.2–31%, in comparison to the reference mortar. The conducted studies indicated increased flexural and compressive strengths along with the share of micro-nano bubbles of gases in the mixing water.
Influence of Temperature on the Mechanical Performance of Unidirectional Carbon Fiber Reinforced Polymer Straps
Authors: Stankovic Danijela , Bisby Luke A. , Terrasi Giovanni P.
Published: April 2021

The performance of pretensioned, laminated, unidirectional (UD), carbon fiber reinforced polymer (CFRP) straps, that can potentially be used for example as bridge deck suspender cables or prestressed shear reinforcements for reinforced concrete slabs and beams, was investigated at elevated temperatures. This paper aims to elucidate the effects of elevated temperature specifically on the tensile performance of pretensioned, pin-loaded straps. Two types of tests are presented: (1) steady state thermal and (2) transient state thermal. Eight steady-state target temperatures in the range of 24 °C to 600 °C were chosen, based on results from dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). Transient state thermal tests were performed at three sustained tensile load levels, namely 10, 15, and 20 kN, corresponding to 25%, 37%, and 50% of the ultimate tensile strength of the pin-loaded straps at ambient temperature. In general, the straps were able to retain about 50% of their ambient temperature ultimate tensile strength (UTS) at 365 °C.
Investigation of Ion Irradiation Effects in Silicon and Graphite Produced by 23 MeV I Beam
Authors: Tomić Luketić Kristina , Karlušić Marko , Gajović Andreja , Fazinić Stjepko , O’Connell Jacques H. , Pielić Borna , Radatović Borna , Kralj Marko
Published: April 2021

Both silicon and graphite are radiation hard materials with respect to swift heavy ions like fission fragments and cosmic rays. Recrystallisation is considered to be the main mechanism of prompt damage anneal in these two materials, resulting in negligible amounts of damage produced, even when exposed to high ion fluences. In this work we present evidence that these two materials could be susceptible to swift heavy ion irradiation effects even at low energies. In the case of silicon, ion channeling and electron microscopy measurements reveal significant recovery of pre-existing defects when exposed to a swift heavy ion beam. In the case of graphite, by using ion channeling, Raman spectroscopy and atomic force microscopy, we found that the surface of the material is more prone to irradiation damage than the bulk.
Effects of Fe Impurities on Self-Discharge Performance of Carbon-Based Supercapacitors
Authors: Du Yuting , Mo Yan , Chen Yong
Published: April 2021

Activated carbon is widely used as an electrode material in supercapacitors due to its superior electrochemical stability, excellent electrical conductivity, and environmental friendliness. In this study, the self-discharge mechanisms of activated carbon electrodes loaded with different contents of Fe impurities (Fe and Fe3O4) were analyzed by multi-stage fitting to explore the tunability of self-discharge. It is was found that a small quantity of Fe impurities on carbon materials improves the self-discharge performance dominated by redox reaction, by adjusting the surface state and pore structure of carbon materials. As the content of Fe impurities increases, the voltage loss of activated carbon with the Fe impurity concentrations of 1.12 wt.% (AF-1.12) decreases by 37.9% of the original, which is attributable to the reduce of ohmic leakage and diffusion, and the increase in Faradic redox at the electrode/electrolyte interface. In summary, self-discharge performance of carbon-based supercapacitors can be adjusted via the surface state and pour structure, which provides insights for the future design of energy storage.
Biomimetic Polymer Surfaces by High Resolution Molding of the Wings of Different Cicadas
Authors: Reid Graham , McCormack James C. , Habimana Olivier , Bayer Fabian , Goromonzi Catherine , Casey Eoin , Cowley Aidan , Kelleher Susan M.
Published: April 2021

Recent studies have shown that insect wings have evolved to have micro- and nanoscale structures on the wing surface, and biomimetic research aims to transfer such structures to application-specific materials. Herein, we describe a simple and cost-effective method of replica molding the wing topographies of four cicada species using UV-curable polymers. Different polymer blends of polyethylene glycol diacrylate and polypropylene glycol diacrylate were used as molding materials and a molding chamber was designed to precisely control the x, y, and z dimensions. Analysis by scanning electron microscopy showed that structures ranged from 148 to 854 nm in diameter, with a height range of 191–2368 nm, and wing patterns were transferred with high fidelity to the crosslinked polymer. Finally, bacterial cell studies show that the wing replicas possess the same antibacterial effect as the cicada wing from which they were molded. Overall, this work shows a quick and simple method for patterning UV-curable polymers without the use of expensive equipment, making it a highly accessible means of producing microstructured materials with biological properties.
Effects of Al Particle Size on the Impact Energy Release of Al-Rich PTFE/Al Composites under Different Strain Rates
Authors: Mao Liang , Wei Chenyang , Hu Rong , Hu Wanxiang , Luo Puguang , Qi Yuxuan , Jiang Chunlan
Published: April 2021

Polytetrafluoroethylene (PTFE)/Al reactive material with different aluminum particle sizes were prepared by molding and sintering, and the effect of aluminum particle size on the impact behavior of PTFE/Al reactive material with a mass ratio of 50:50 was investigated. The results show that aluminum particle size has significant effects on the shock-reduced reaction diffusion, reaction speed, and degree of reaction of the PTFE/Al reactive material. At a moderate strain rate, the reaction delay of PTFE/Al increased, and the reaction duration and degree decreased, with the increase of aluminum particle size. Under the strong impact of explosive loading, aluminum particle size has little effect on the reaction delay, which maintains at about 1.5 μs–2.5 μs, but the reaction durability and degree of reaction of PTFE/Al decrease with increasing aluminum particle size. There is also a strain rate threshold for the shock-induced reaction of PTFE/Al reactive material, which is closely related to aluminum particle size. The shock-induced reaction occurs when the strain rate threshold is exceeded.
Giant Stress-Impedance Effect in CoFeNiMoBSi Alloy in Variation of Applied Magnetic Field
Authors: Gazda Piotr , Nowicki Michał
Published: April 2021

The article presents the stress impedance investigation of CoFeNiMoBSi alloy in variation of the applied magnetic field. In order to carry out the study, a specialized stand was developed that allows for loading the sample with stresses and simultaneous action of the DC (direct current) magnetizing field. The tests were carried out for as-cast and Joule annealed samples. The significant influence of the magnetizing field acting on the sample on the stress-impedance results was demonstrated and the dependence of the maximum impedance change in the stress-impedance effect was determined, depending on the field acting. The obtained results are important due to the potential use of the stress-impedance effect for the construction of stress sensors.
The Green Synthesis of 2D Copper Nanosheets and Their Light Absorption
Authors: Lee Suhyun , Wang Suming , Wern Chien , Yi Sung
Published: April 2021

In this study, a new green synthesis method for two-dimensional (2D) copper nanosheets is developed using methylsulfonylmethane (DMSO2). The chemical composition and light absorption of 2D copper nanosheets are also studied. A new green method is mainly to utilize DMSO2, which is environmentally friendly enough to be considered a food-grade chemical, unlike the conventional method using toxic chemicals, such as ammonia and hydrazine (N2H4). With a reducing agent, the aggregation of uncertain copper products was produced in the absence of DMSO2, while 2D copper nanosheets were formed in the presence of DMSO2. The optimum concentration of DMSO2 as a surfactant was determined to be 2 M, resulting in large surface areas with regular edges. FTIR spectrum confirmed C–H bonding from DMSO2 used to synthesize 2D copper nanosheets. The light absorption peak was revealed at 800 nm in the UV–vis spectrum. This proposed new green method not only has a simpler process than the conventional methods, such as hydrothermal method and chemical bath deposition, but also substitutes toxic chemicals with DMSO2. 2D copper nanosheets can be used for various applications, including conductive filler or ink in the flexible electronics and laser photonics fields.
Change of 0.34Cr-1Ni-Mo-Fe Steel Dislocation Structure in Plasma Electrolyte Hardening
Authors: Rakhadilov Bauyrzhan , Satbayeva Zarina , Ramankulov Sherzod , Shektibayev Nurdaulet , Zhurerova Laila , Popova Natalya , Uazyrkhanova Gulzhaz , Sagdoldina Zhuldyz
Published: April 2021

This work deals with the study of changes in the dislocation structure and quantitative characteristics, as well as morphological components, of 0.34Cr-1Ni-Mo-Fe steel before and after plasma electrolytic hardening. According to the electron microscopic studies of the fine structure of 0.34Cr-1Ni-Mo-Fe steel before and after plasma electrolytic hardening, 0.34Cr-1Ni-Mo-Fe steel is a multiphase material containing an α-phase, a γ-phase (retained austenite), and a cementite and carbide phase. It was revealed that, morphologically, the α-phase in the initial state, generally, is present in the form of: lamellar pearlite with a volume fraction of 35%, a ferritocarbide mixture with a volume fraction of 45%, and fragmented ferrite with a volume fraction of 20% of the material. After surface hardening, the morphological components of the structure changed: packet–lamellar martensite with volume fractions of 60% and 40%, 5% and 7% of γ-phase as residual austenite in the crystals of packet–lamellar martensite, 0.6% and 1.5% of cementite in crystals of packet–lamellar martensite, and 0.15% and 0.35% of complex carbide M23C6 in crystals of packet–lamellar martensite, respectively, were observed. The quantitative characteristics of the dislocation structure were estimated by the following calculated indices of packet and lamellar martensite: scalar (ρ) and excess (ρ±) density of dislocations, the value of the curvature-torsion of the crystal lattice (χ), the amplitude of long-range internal stresses (σd), and the amplitude of shear stresses (σL), according to which the plastic nature of the bending-torsion of the crystal lattice was confirmed (σL > σd).
Improved Bacteriostatic and Anticorrosion Effects of Polycaprolactone/Chitosan Coated Magnesium via Incorporation of Zinc Oxide
Authors: Bakhsheshi-Rad Hamid Reza , Hamzah Esah , Ying Wong See , Razzaghi Mahmood , Sharif Safian , Ismail Ahmad Fauzi , Berto Filippo
Published: April 2021

Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on the corrosion resistance and antibacterial activity of magnesium. The PCL/CS film presented a porous structure with thickness of about 40–50 μm, while after incorporation of ZnO into the PCL/CS, a homogenous film without pores and defects was attained. The ZnO embedded in PCL/CS enhanced corrosion resistance by preventing corrosive ions diffusion in the magnesium substrate. The corrosion, antibacterial, and cell interaction mechanism of the PCL/CS/ZnO composite coating is discussed in this study. In vitro cell culture revealed that the PCL/CS coating with low loaded ZnO significantly improved cytocompatibility, but coatings with high loaded ZnO were able to induce some cytotoxicity osteoblastic cells. It was also found that enhanced antibacterial activity of the PCL/CS/ZnO coating against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, while less significant antibacterial activity was detected for uncoated Mg and PCL/CS coating. Based on the results, the PCL/CS coatings loaded with low ZnO content may be recommended as a candidate material for biodegradable Mg-based orthopedic implant applications.
Magneto-Erythrocyte Membrane Vesicles’ Superior T2 MRI Contrast Agents to Magneto-Liposomes
Authors: Kostevšek Nina , Miklavc Patricija , Kisovec Matic , Podobnik Marjetka , Al-Jamal Wafa , Serša Igor
Published: April 2021

Despite their high potential, most of the clinically approved iron oxide (IO)-based contrast agents for magnetic resonance imaging (MRI) have been withdrawn from the market either due to safety issues or lack of sales. To address this challenge, erythrocyte membranes have been used to prepare IO-based T2 contrast agents with superior MRI properties and higher safety margin. A simple formulation procedure has been proposed, and the nanostructures’ morphology and physicochemical properties have been evaluated. We compared their performance in terms of contrast ability in MRI to the more clinically established magneto-liposomes and non-encapsulated nanoparticles (NPs). The encapsulation of 5-nm iron oxide nanoparticles (IO NPs) in the liposomes and erythrocyte membrane vesicles (EMVs) led to a significant improvement in their r2 relaxivity. r2 values increased to r2 = 188 ± 2 mM−1s−1 for magneto-liposomes and r2 = 269 ± 3 mM−1s−1 for magneto-erythrocyte membranes, compared to “free” IO NPs with (r2 = 12 ± 1 mM−1 s−1), measured at a 9.4 T MRI scanner. The superiority of magneto-erythrocyte membranes in terms of MRI contrast efficacy is clearly shown on T2-weighted MR images. Our study revealed the hemocompatibility of the developed contrast agents in the MRI-relevant concentration range.
Tails of the Moments for Sums with Dominatedly Varying Random Summands
Authors: Dirma Mantas , Paukštys Saulius , Šiaulys Jonas
Published: April 2021

The asymptotic behaviour of the tail expectation ?E(Snξ)α?{Snξ>x} is investigated, where exponent α is a nonnegative real number and Snξ=ξ1+…+ξn is a sum of dominatedly varying and not necessarily identically distributed random summands, following a specific dependence structure. It turns out that the tail expectation of such a sum can be asymptotically bounded from above and below by the sums of expectations ?Eξiα?{ξi>x} with correcting constants. The obtained results are extended to the case of randomly weighted sums, where collections of random weights and primary random variables are independent. For illustration of the results obtained, some particular examples are given, where dependence between random variables is modelled in copulas framework.
A Fuzzy Economic Dynamic Model
Authors: Ferrer-Comalat Joan Carles , Corominas-Coll Dolors , Linares-Mustarós Salvador
Published: April 2021

In the study presented here, fuzzy logic was used to analyze the behavior of a model of economic dynamics that assumes income to be in equilibrium when it is composed of consumption and investment, that is, when savings and investment are equal. The study considered that consumption and savings depend on the income of the previous period through uncertain factors, and, at the same time, that investment is an uncertain magnitude across various periods, represented as a fuzzy number with a known membership function. Under these conditions, the model determines the factor of income growth and investments required to maintain equilibrium, as well as the uncertain values of income for the different periods, expressed through fuzzy numbers. The study also analyzes the conditions for their convergence and the fuzzy value that income represents in equilibrium.