bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatty Acid Binding Protein 3 (FABP3) and Apolipoprotein E4 (ApoE4) as Lipid Metabolism-Related Biomarkers of Alzheimer’s Disease
Authors: Dulewicz Maciej , Kulczyńska-Przybik Agnieszka , Słowik Agnieszka , Borawska Renata , Mroczko Barbara
Published: July 2021

Background: Lipid metabolism-related biomarkers gain increasing researchers interest in the field of neurodegenerative disorders. Mounting evidence have indicated the role of fatty acid-binding proteins and pathology lipid metabolism in Alzheimer’s Disease (AD). The imbalance of fatty acids (FA) and lipids may negatively affect brain functions related to neurodegenerative disorders. The ApoE4 and FABP3 proteins may reflect processes leading to neurodegeneration. This study aimed to evaluate the relationship between the CSF levels of FABP3 and ApoE4 proteins and cognitive decline as well as the diagnostic performance of these candidate biomarkers in AD and mild cognitive impairment (MCI). Methods: A total of 70 subjects, including patients with AD, MCI, and non-demented controls, were enrolled in the study. CSF concentrations of FABP3 and ApoE4 were measured using immunoassay technology. Results: Significantly higher CSF concentrations of FABP3 and ApoE4 were observed in AD patients compared to MCI subjects and individuals without cognitive impairment. Both proteins were inversely associated with Aβ42/40 ratio: ApoE4 (rho = −0.472, p < 0.001), and FABP3 (rho = −0.488, p < 0.001) in the whole study group, respectively. Additionally, FABP3 was negatively correlated with Mini-Mental State Examination score in the whole study cohort (rho = −0.585 p < 0.001). Conclusion: Presented results indicate the pivotal role of FABP3 and ApoE4 in AD pathology as lipid-related biomarkers, but studies on larger cohorts are needed.
Conducting Polymeric Composites Based on Intrinsically Conducting Polymers as Electromagnetic Interference Shielding/Microwave Absorbing Materials—A Review
Authors: Soares Bluma Guenther , Barra Guilherme M. O. , Indrusiak Tamara
Published: July 2021

The development of sophisticated telecommunication equipment and other electro-electronic devices resulted in a kind of electromagnetic pollution that affects the performance of other equipment as well as the health of human beings. Intrinsically conducting polymers (ICP), mainly polyaniline and polypyrrole, have been considered as promising candidates for applications in efficient electromagnetic interference shielding (EMI) due to their ease of preparation, light weight, good conductivity and corrosion resistance. One of the important advantages of these materials is the capability to interact with the EM radiation through both absorption and reflection mechanisms thus enlarging the field of application. In this context, this review article describes a recent overview of the existing methods to produce intrinsically conducting polymers and their blends for electromagnetic shielding application. Additionally, it highlights the relationship between preparation methods reported in the literature with the structure and properties, such as electrical conductivity, electromagnetic shielding effectiveness (EMI SE), complex permittivity and permeability of these materials. Furthermore, a brief theory related to the electromagnetic mechanism and techniques for measuring the microwave absorbing properties are also discussed.
Drosophila Corazonin Neurons as a Hub for Regulating Growth, Stress Responses, Ethanol-Related Behaviors, Copulation Persistence and Sexually Dimorphic Reward Pathways
Authors: Khan Ziam , Tondravi Maya , Oliver Ryan , Vonhoff Fernando J.
Published: July 2021

The neuronal mechanisms by which complex behaviors are coordinated and timed often involve neuropeptidergic regulation of stress and reward pathways. Recent studies of the neuropeptide Corazonin (Crz), a homolog of the mammalian Gonadotrophin Releasing Hormone (GnRH), have suggested its crucial role in the regulation of growth, internal states and behavioral decision making. We focus this review on Crz neurons with the goal to (1) highlight the diverse roles of Crz neuron function, including mechanisms that may be independent of the Crz peptide, (2) emphasize current gaps in knowledge about Crz neuron functions, and (3) propose exciting ideas of novel research directions involving the use of Crz neurons. We describe the different developmental fates of distinct subsets of Crz neurons, including recent findings elucidating the molecular regulation of apoptosis. Crz regulates systemic growth, food intake, stress responses and homeostasis by interacting with the short Neuropeptide F (sNPF) and the steroid hormone ecdysone. Additionally, activation of Crz neurons is shown to be pleasurable by interacting with the Neuropeptide F (NPF) and regulates reward processes such as ejaculation and ethanol-related behaviors in a sexually dimorphic manner. Crz neurons are proposed to be a motivational switch regulating copulation duration using a CaMKII-dependent mechanism described as the first neuronal interval timer lasting longer than a few seconds. Lastly, we propose ideas to use Crz neuron-induced ejaculation to study the effects of fictive mating and sex addiction in flies, as well as to elucidate dimorphic molecular mechanisms underlying reward behaviors and feeding disorders.
A Method for Supervisory Control of Manipulator of Underwater Vehicle
Authors: Konoplin Alexander , Filaretov Vladimir , Yurmanov Alexander
Published: July 2021

A novel method for supervisory control of multilink manipulators mounted on underwater vehicles is considered. This method is designed to significantly increase the level of automation of manipulative operations, by the building of motion trajectories for a manipulator working tool along the surfaces of work objects on the basis of target indications given by the operator. This is achieved as follows: The operator targets the camera (with changeable spatial orientation of optical axis) mounted on the vehicle at the work object, and uses it to set one or more working point on the selected object. The geometric shape of the object in the work area is determined using clouds of points obtained from the technical vision system. Depending on the manipulative task set, the spatial motion trajectories and the orientation of the manipulator working tool are automatically set using the spatial coordinates of these points lying on the work object surfaces. The designed method was implemented in the C++ programming language. A graphical interface has also been created that provides rapid testing of the accuracy of overlaying the planned trajectories on the mathematically described surface of a work object. Supervisory control of an underwater manipulator was successfully simulated in the V-REP environment.
Research on Improving the Working Efficiency of Hydraulic Jet Submarine Cable Laying Machine
Authors: Lu Zhifei , Cao Chen , Ge Yongqiang , He Jiamin , Yu Zhou , Chen Jiawang , Zheng Xinlong
Published: July 2021

The anchoring and hooking of ships, bedrock friction and biological corrosion threaten the safety and stability of submarine cables. A hydraulic jet submarine cable laying machine manages to bury the submarine cables deep into the seabed, and effectively reduces the occurrence of external damage to the submarine cables. This machine uses a hydraulic jet system to realize trenching on the seabed. However, the hydraulic jet submarine cable laying machine has complicated operation and high power consumption with high requirements on the mother ship, and it is not yet the mainstream trenching method. In this paper, a mathematical model for the hydraulic jet nozzle of the submarine cable laying machine is established, and parameters that affect the trenching efficiency are studied. The effects of jet target distance, flow, angle and nozzle spacing on the working efficiency of the burying machine are analyzed by setting up a double-nozzle model. The results of the theory, numerical simulation and experiment show that the operational efficiency of the hydraulic jet submarine cable laying machine can be distinctly improved by setting proper jet conditions and parameters.
Numerical Investigation of the Inland Transport Impact on the Bed Erosion and Transport of Suspended Sediment: Propulsive System and Confinement Effect
Authors: Kaidi Sami , Smaoui Hassan , Sergent Philippe
Published: July 2021

For competitive reasons, inland ships as maritime ships are increasingly larger with powerful propulsive systems. The impact of this evolution on the environment is multiple. One of the major impacts is the erosion of the channel bed and the sediment suspension. This erosion phenomenon is essentially caused by the turbulent flow around the ship generated by its movement as well as its propulsive system. Hence, for a better prediction and understanding of this phenomenon, it is indispensable to simulate with great precision the flow around the ship hull and the induced shear stress at the bottom. Different ways were used in the past to estimate the shear stress at the waterway bottom. Some of these ways are empirical, analytical and numerical using shallow water models. In the present work to study the erosion phenomenon caused by the inland transport, a sedimentary transport model was developed and implemented in the Computational Fluid Dynamics (CFD) model (Fluent) as external code. The coupled model was firstly verified and validated using measurements. The validated model was subsequently used to assess the influence of several parameters: depth (h) to draught (T) ratio, ship advance ratio (J), ship speed and sediment size (d50). The first results show clearly that the coupled model behaves correctly and gives very satisfactory results. The impact of each parameter was compared and analyzed.
The Negative Effect of Protein Phosphatase Z1 Deletion on the Oxidative Stress Tolerance of Candida albicans Is Synergistic with Betamethasone Exposure
Authors: Jakab Ágnes , Emri Tamás , Csillag Kinga , Szabó Anita , Nagy Fruzsina , Baranyai Edina , Sajtos Zsófi , Géczi Dóra , Antal Károly , Kovács Renátó , Szabó Krisztina , Dombrádi Viktor , Pócsi István
Published: July 2021

The glucocorticoid betamethasone (BM) has potent anti-inflammatory and immunosuppressive effects; however, it increases the susceptibility of patients to superficial Candida infections. Previously we found that this disadvantageous side effect can be counteracted by menadione sodium bisulfite (MSB) induced oxidative stress treatment. The fungus specific protein phosphatase Z1 (CaPpz1) has a pivotal role in oxidative stress response of Candida albicans and was proposed as a potential antifungal drug target. The aim of this study was to investigate the combined effects of CaPPZ1 gene deletion and MSB treatment in BM pre-treated C. albicans cultures. We found that the combined treatment increased redox imbalance, enhanced the specific activities of antioxidant enzymes, and reduced the growth in cappz1 mutant (KO) strain. RNASeq data demonstrated that the presence of BM markedly elevated the number of differentially expressed genes in the MSB treated KO cultures. Accumulation of reactive oxygen species, increased iron content and fatty acid oxidation, as well as the inhibiting ergosterol biosynthesis and RNA metabolic processes explain, at least in part, the fungistatic effect caused by the combined stress exposure. We suggest that the synergism between MSB treatment and CaPpz1 inhibition could be considered in developing of a novel combinatorial antifungal strategy accompanying steroid therapy.
Evolution of CT Findings and Lung Residue in Patients with COVID-19 Pneumonia: Quantitative Analysis of the Disease with a Computer Automatic Tool
Authors: Grassi Roberto , Cappabianca Salvatore , Urraro Fabrizio , Granata Vincenza , Giacobbe Giuliana , Magliocchetti Simona , Cozzi Diletta , Fusco Roberta , Galdiero Roberta , Picone Carmine , Belfiore Maria Paola , Reginelli Alfonso , Atripaldi Umberto , Picascia Ornella , Coppola Michele , Bignardi Elio , Grassi Roberta , Miele Vittorio
Published: July 2021

Purpose: the purpose of this study was to assess the evolution of computed tomography (CT) findings and lung residue in patients with COVID-19 pneumonia, via quantified evaluation of the disease, using a computer aided tool. Materials and methods: we retrospectively evaluated 341 CT examinations of 140 patients (68 years of median age) infected with COVID-19 (confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR)), who were hospitalized, and who received clinical and CT examinations. All CTs were evaluated by two expert radiologists, in consensus, at the same reading session, using a computer-aided tool for quantification of the pulmonary disease. The parameters obtained using the computer tool included the healthy residual parenchyma, ground glass opacity, consolidation, and total lung volume. Results: statistically significant differences (p value ≤ 0.05) were found among quantified volumes of healthy residual parenchyma, ground glass opacity (GGO), consolidation, and total lung volume, considering different clinical conditions (stable, improved, and worsened). Statistically significant differences were found among quantified volumes for healthy residual parenchyma, GGO, and consolidation (p value ≤ 0.05) between dead patients and discharged patients. CT was not performed on cadavers; the death was an outcome, which was retrospectively included to differentiate findings of patients who survived vs. patients who died during hospitalization. Among discharged patients, complete disease resolutions on CT scans were observed in 62/129 patients with lung disease involvement ≤5%; lung disease involvement from 5% to 15% was found in 40/129 patients, while 27/129 patients had lung disease involvement between 16 and 30%. Moreover, 8–21 days (after hospital admission) was an “advanced period” with the most severe lung disease involvement. After the extent of involvement started to decrease—particularly after 21 days—the absorption was more obvious. Conclusions: a complete disease resolution on chest CT scans was observed in 48.1% of discharged patients using a computer-aided tool to quantify the GGO and consolidation volumes; after 16 days of hospital admission, the abnormalities identified by chest CT began to improve; in particular, the absorption was more obvious after 21 days.
The Slow Death of Capital Protection
Authors: Bauer Christian , Rieger Marc Oliver
Published: July 2021

Capital protected products are a special type of structured retail products that guarantee a minimum amount of payment at maturity. They were the earliest type of structured products and are very popular with risk averse investors, but nevertheless have become rare in the past years. Using a unique dataset of all structured products issued in Switzerland, one of the biggest markets for such products in the world, we investigate why this has been the case, and argue that it is to a large degree an effect of the zero-interest policy of central banks.
Geographic Scope and Real Estate Firm Performance during the COVID-19 Pandemic
Authors: Chu Xiaoling , Lu Chiuling , Tsang Desmond
Published: July 2021

This study examines the effect of geographic scope in mitigating the adverse impact of the COVID-19 pandemic in the real estate sector. Utilizing the Chinese setting over the two-month period in 2020 from the beginning of the outbreak to the successful containment of the spread of virus, we show that while the pandemic has negatively impacted real estate firm returns, firms with broader geographic scope and more geographically diversified property allocations have managed to better endure the crisis. We further find that firms with higher leverage report lower returns during the pandemic irrespective of their geographic scope, but larger firms can lessen the adverse impact of the pandemic only if they have adopted a more diversified strategy. Overall, our study provides novel evidence on the benefit of diversification by demonstrating the importance of geographic scope and diversification at times of crises. Specifically, we show corporate diversification could be especially useful to mitigate the negative stock market reactions resulting from the pandemic. Moreover, diversification could even become essential for larger firms that are expected by the market to be more diversified.
Effects of Institutions on Spatial Patterns of Manufacturing Industries and Policy Implications in Metropolitan Areas: A Case Study of Wuhan, China
Authors: Zhou Min , Yuan Man , Huang Yaping , Lin Kaixuan
Published: July 2021

Manufacturing space is a spatial system that combines the interaction between capital and institutions at the enterprise, industry, and spatial levels. It is also an important functional type that promotes the spatial evolution of big cities. Most studies focus on the effects of a single institutional type on the manufacturing space of big cities and lack systematic and complete exploration of the institutional mechanism. Current empirical research on typical industrial cities in China is insufficient. This study uses a GIS spatial analysis technique and a Poisson regression model to analyze the mechanism by which institutions have influenced the spatial patterns of manufacturing industries in the Wuhan metropolitan area since the 1990s. The results show that land policy, development zone policy, urban planning, transportation strategy, and eco-environmental policy all have a significant impact on the restructuring process and distribution pattern of the manufacturing industries through incentives and constraints. This study expands our understanding of the influence mechanism of manufacturing spatial patterns and proposes spatial guiding strategies and policy implications for the spatial transformation of urban manufacturing.
Assessment and Spatial-Temporal Evolution Analysis of Urban Land Use Efficiency under Green Development Orientation: Case of the Yangtze River Delta Urban Agglomerations
Authors: Tang Yingkai , Wang Kun , Ji Xuanming , Xu He , Xiao Yangqing
Published: July 2021

Rapid urbanization has provided a strong impetus for the economic growth of China, but it has also caused many problems such as inefficient urban land use and environmental pollution. With the popularization of the concept of green and sustainable development, the Environmental-Social-Governance (ESG) assessment concept is widely accepted. The government and residents are paying more and more attention to environmental issues in urban development, and environmental protection has formed an important part of urban development. In this context, this study takes 26 cities in the Yangtze River Delta as examples to build an evaluation system for urban land-use efficiency under green development orientation. The evaluation system takes into account the inputs of land, capital, labor, and energy factors in the process of urban development. Based on emphasizing economic output, the social benefits and undesired outputs brought about by urban development are taken into account. This paper measures urban land use efficiency by the super-efficiency SBM model, and on this basis, analyses the spatial-temporal evolution characteristics of urban land-use efficiency. Further, this paper measures urban land use efficiency without considering undesired outputs and compares the two evaluation methods. Again, the comparison illustrates the rationality of urban land use efficiency evaluation system under green development orientation.
Migrant Learners of Basque as New Speakers: Language Authenticity and Belonging
Authors: Augustyniak Anna
Published: July 2021

Language issues related to identity negotiation in minoritised language contexts, including those related to the category of “new speakers”, have often been studied in relation to local language dichotomies and national populations. This paper will examine identity construction among migrant learners of Basque from outside of Spain, looking at migrants as a diverse population and as a particular group of new speakers of Basque. By analysing the ways in which migrant learners position themselves as (not) belonging to “Basqueness” as a group identity, it points to the underlying language ideologies that guide language and identity categories, such as native Basque speakers or new speakers, within the essentialising and non-essentialising ideological influences. It will aim to answer how migrants employ identity categories or contest their use in discourse and establish the extent of the relation between perceived linguistic competence in Basque, the use of Basque by migrants and the ideologies of authenticity, legitimacy and ownership. The methodology applied is ethnographically oriented and linguistic data analysis is performed through a thematic discourse analysis.
Strengthening Writing Voices and Identities: Creative Writing, Digital Tools and Artmaking for Spanish Heritage Courses
Authors: Parra María Luisa
Published: July 2021

This paper presents an analysis of poems, digital art, and accompanying analytical essays authored by four college students taking an advanced Spanish as heritage language. This paper highlights the ways in which creative writing, along with digital tools for artmaking, can enhance the teaching of language literacy to heritage learners. It proposes that creative writing opens up simultaneously meaningful and transformative experiences for students: they engage with the performativity of creative writing, use their voices beyond the constraints of specific genre conventions, engage with critical language awareness exercises, and become motivated to use their writing in order to reach out to the wider Spanish-speaking communities outside the classroom. Digital technologies played a key role in the creative process, as they provided a range of artistic tools and flexibilities that enhanced and complemented the power of the written word. The paper aims to contribute to the pedagogy of Spanish heritage courses and to expand the notions of literacy and writing under which we work in the SHL classroom.
The Interplay of Mitophagy and Inflammation in Duchenne Muscular Dystrophy
Authors: Reid Andrea L. , Alexander Matthew S.
Published: July 2021

Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease caused by a pathogenic disruption of the DYSTROPHIN gene that results in non-functional dystrophin protein. DMD patients experience loss of ambulation, cardiac arrhythmia, metabolic syndrome, and respiratory failure. At the molecular level, the lack of dystrophin in the muscle results in myofiber death, fibrotic infiltration, and mitochondrial dysfunction. There is no cure for DMD, although dystrophin-replacement gene therapies and exon-skipping approaches are being pursued in clinical trials. Mitochondrial dysfunction is one of the first cellular changes seen in DMD myofibers, occurring prior to muscle disease onset and progresses with disease severity. This is seen by reduced mitochondrial function, abnormal mitochondrial morphology and impaired mitophagy (degradation of damaged mitochondria). Dysfunctional mitochondria release high levels of reactive oxygen species (ROS), which can activate pro-inflammatory pathways such as IL-1β and IL-6. Impaired mitophagy in DMD results in increased inflammation and further aggravates disease pathology, evidenced by increased muscle damage and increased fibrosis. This review will focus on the critical interplay between mitophagy and inflammation in Duchenne muscular dystrophy as a pathological mechanism, as well as describe both candidate and established therapeutic targets that regulate these pathways.
Testing of Chemically Activated Cellulose Fibers as Adsorbents for Treatment of Arsenic Contaminated Water
Authors: Ciopec Mihaela , Biliuta Gabriela , Negrea Adina , Duțeanu Narcis , Coseri Sergiu , Negrea Petru , Ghangrekar Makarand
Published: July 2021

Exposure to different arsenic concentrations (higher than 10 μg/L), either due to the direct consumption of contaminated drinking water or indirectly by using contaminated food is harmful for human health. Therefore, it is important to remove arsenic from aqueous solutions. Among many arsenic removal technologies, adsorption offers a promising solution with a good efficiency, however the material used as adsorbent play a very vital role. The present investigation evaluated the behavior of two cellulose-based adsorbent materials, i.e., viscose fibers (V) and its TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) derivative, obtained by using the well-established TEMPO-mediated protocol (VF). Due to the known arsenic affinity for Fe ions the two materials were later doped with it. This was done after a preliminary functionalization with di-2-ethylhexyl phosphoric acid (DEHPA), to obtain two materials: V-DEHPA-Fe and VF-DEHPA-Fe. Arsenic adsorption is known to be pH dependent (between 6 and 8); therefore, the optimal pH range for As(V) adsorption has been established. In order to evaluate the adsorption mechanism for both the synthesized materials, the influence of contact time, temperature and initial concentration was evaluated. Langmuir, Freundlich and Sips equilibrium isotherm models were used in order to determine the ability of the model to describe As(V) adsorption process. The maximum adsorption capacity of the material V-DEHPA-Fe was 247.5 µg As(V)/g with an As(V) initial concentration of 5 mg/L and for the material VF-DEHPA-Fe it was 171.2 µg As(V)/g with initial concentration of 5 mg/L.
Van der Waals Heterostructures—Recent Progress in Electrode Materials for Clean Energy Applications
Authors: Blackstone Chance , Ignaszak Anna
Published: July 2021

The unique layered morphology of van der Waals (vdW) heterostructures give rise to a blended set of electrochemical properties from the 2D sheet components. Herein an overview of their potential in energy storage systems in place of precious metals is conducted. The most recent progress on vdW electrocatalysis covering the last three years of research is evaluated, with an emphasis on their catalytic activity towards the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). This analysis is conducted in pair with the most active Pt-based commercial catalyst currently utilized in energy systems that rely on the above-listed electrochemistry (metal–air battery, fuel cells, and water electrolyzers). Based on current progress in HER catalysis that employs vdW materials, several recommendations can be stated. First, stacking of the two types vdW materials, with one being graphene or its doped derivatives, results in significantly improved HER activity. The second important recommendation is to take advantage of an electronic coupling when stacking 2D materials with the metallic surface. This significantly reduces the face-to-face contact resistance and thus improves the electron transfer from the metallic surface to the vdW catalytic plane. A dual advantage can be achieved from combining the vdW heterostructure with metals containing an excess of d electrons (e.g., gold). Despite these recent and promising discoveries, more studies are needed to solve the complexity of the mechanism of HER reaction, in particular with respect to the electron coupling effects (metal/vdW combinations). In addition, more affordable synthetic pathways allowing for a well-controlled confined HER catalysis are emerging areas.
Influence of Gating System Parameters of Die-Cast Molds on Properties of Al-Si Castings
Authors: Gašpár Štefan , Coranič Tomáš , Majerník Ján , Husár Jozef , Knapčíková Lucia , Gojdan Dominik , Paško Ján
Published: July 2021

The resulting quality of castings indicates the correlation of the design of the mold inlet system and the setting of technological parameters of casting. In this study, the influence of design solutions of the inlet system in a pressure mold on the properties of Al-Si castings was analyzed by computer modelling and subsequently verified experimentally. In the process of computer simulation, the design solutions of the inlet system, the mode of filling the mold depending on the formation of the casting and the homogeneity of the casting represented by the formation of shrinkages were assessed. In the experimental part, homogeneity was monitored by X-ray analysis by evaluating the integrity of the casting and the presence of pores. Mechanical properties such as permanent deformation and surface hardness of castings were determined experimentally, depending on the height of the inlet notch. The height of the inlet notch has been shown to be a key factor, significantly influencing the properties of the die-cast parts and influencing the speed and filling mode of the mold cavity. At the same time, a significant correlation between porosity and mechanical properties of castings is demonstrated. With the increasing share of porosity, the values of permanent deformation of castings increased. It is shown that the surface hardness of castings does not depend on the integrity of the castings but on the degree of subcooling of the melt in contact with the mold and the formation of a fine-grained structure in the peripheral zones of the casting.
Zeolite Lightweight Repair Renders: Effect of Binder Type on Properties and Salt Crystallization Resistance
Authors: Pavlíková Milena , Kapicová Adéla , Pivák Adam , Záleská Martina , Lojka Michal , Jankovský Ondřej , Pavlík Zbyšek
Published: July 2021

Rendering mortars with lightweight zeolite aggregates were designed and tested. The effect of the type of binder used was also researched. For the hardened mortars, macrostructural parameters, mechanical characteristics, hygric and thermal properties were assessed. Specific attention was paid to the analysis of the salt crystallization resistance of the developed rendering mortars. Quartz sand was fully replaced in the composition of mortars with zeolite gave materials with low density, high porosity, sufficient mechanical strength, high water vapor permeability and high water absorption coefficient, which are technical parameters required for repair rendering mortars as prescribed in the WTA directive 2-9-04/D and EN 998-1. Moreover, the zeolite enhanced mortars exhibit good thermal insulation performance and high sorption capacity. The examined rendering mortars were found to be well durable against salt crystallization, which supports their applicability in salt-laden masonry. Based on the compatibility of the repair materials with those originally used, the lime and natural hydraulic lime zeolite mortars can be used as rendering mortars for the repair of historical and heritage buildings. The cement-lime zeolite render is applicable for repair purposes only in the case of the renewal of masonry in which Portland cement-based materials were originally used.
Bond Relationship of Carbon Fiber-Reinforced Polymer (CFRP) Strengthened Steel Plates Exposed to Service Temperature
Authors: Lye Hui Li , Mohammed Bashar S. , Wahab Mohamed Mubarak Abdul , Liew Mohd Shahir
Published: July 2021

Emerging as a new technology, carbon fiber-reinforced polymer (CFRP) has been introduced to rehabilitate and strengthen steel structures using an adhesive agent. However, the outdoor service temperature is potentially degrading to the mechanical strength of the adhesive, as well as affecting the bonding of the strengthened steel structure. Therefore, this paper aims to investigate the bond relationship of CFRP-strengthened steel plates exposed to service temperatures. Two types of experiments were conducted to determine the tensile and flexural performance of CFRP-strengthened steel plates. The experiments were designed using a Box–Behnken design (BBD) and response surface methodology (RSM) by considering three parameters: service temperature (25 °C, 45 °C and 70 °C), number of CFRP layers (one, three and five layers) and bond length (40, 80 and 120 mm). The findings show the dominant failure mode transformed from adhesion failure between steel and adhesive interfaces to adhesion failure between CFRP and adhesive interfaces as the service temperature increased. The tensile strength improved by 25.62% when the service temperature increased. Field emission scanning electron microscope (FESEM) analysis proved that the strength enhancement is due to the densification and reduction of the adhesive particle microstructure gaps through the softening effect at service temperature. However, service temperature is found to have less impact on flexural strength. Incorporating the experimental results in RSM, two quadratic equations were developed to estimate the tensile and flexural strength of CFRP-strengthened steel plates. The high coefficient of determination, R2, yields at 0.9936 and 0.9846 indicate the high reliability of the models. Hence, it can be used as an estimation tool in the design stage.
Study on Properties of Bone Glue/Polyurethane Composite Modified Asphalt and Its Mixture
Authors: Yan Wei , Ou Yangjia , Xie Jing , Huang Tuo , Peng Xinghai
Published: July 2021

Composite modification technology is widely used in the materials field. To enhance the property of polyurethane modified asphalt and realize its application in road engineering, the bone glue/polyurethane composite modified asphalt (CMA) was prepared using bone glue, polyurethane, and neat asphalt in this research. The bone glue content ranges 5–10%, that of the polyurethane is 1–5%. The relationship between the modifier’s content and the conventional properties and rheological properties of CMA was revealed by response surface methodology (RSM). The CMA performance was further verified under the optimal content of the bone glue and polyurethane. The differences of properties of styrene–butadienestyrene (SBS) modified asphalt mixture, neat asphalt mixture, and bone glue/polyurethane CMA mixture were compared and analyzed by using the pavement performance test. The results showed that the CMA’s conventional properties and rheological properties are improved. The optimal bone glue content and polyurethane content determined by RSM are 6.848% and 2.759%, respectively. The low-temperature crack resistance and water stability of the CMA mixture are enhanced, better than neat asphalt mixture and SBS modified asphalt mixture. The CMA mixture’s dynamic stability is 85% of SBS modified asphalt mixture, but it is 2.4 times of neat asphalt mixture. The result indicated that the bone glue/polyurethane CMA mixture still has certain advantages of high-temperature stability. In this research, the composite modification of bone glue and polyurethane can significantly enhance the characteristic of asphalt and asphalt mixture and provide a new method for applying and promoting polyurethane modified asphalt in road engineering.
Experimental and Theoretical Study of Radiation Shielding Features of CaO-K2O-Na2O-P2O5 Glass Systems
Authors: Sayyed M. I. , Albarzan Badriah , Almuqrin Aljawhara H. , El-Khatib Ahmed M. , Kumar Ashok , Tishkevich Daria I. , Trukhanov Alex V. , Elsafi Mohamed
Published: July 2021

The gamma radiation shielding ability for CaO-K2O-Na2O-P2O5 glasses were experimentally determined between 0.0595 and 1.41 MeV. The experimental MAC results were compared with theoretical results obtained from the XCOM software to test the accuracy of the experimental values. Additionally, the effect of increasing the P2O5 in the glass composition, or reducing the Na2O content, was evaluated at varying energies. For the fabricated glasses, the experimental data strongly agreed with the XCOM results. The effective atomic number (Zeff) of the fabricated glasses was also determined. The Zeff values start out at their maximum (12.41–12.55) at the lowest tested energy, 0.0595 MeV, and decrease to 10.69–10.80 at 0.245 MeV. As energy further increases, the Zeff values remain almost constant between 0.344 and 1.41 MeV. The mean free path (MFP) of the fabricated glasses is investigated and we found that the lowest MFP value occurs at the lowest tested energy, 0.0595 MeV, and lies within the range of 1.382–1.486 cm, while the greatest MFP can be found at the highest tested energy, 1.41 MeV, within the range of 8.121–8.656 cm. At all energies, the KCNP40 sample has the lowest MFP, while the KCNP60 sample has the greatest. The half value layer (HVL) for the KCNP-X glasses is determined. For all the selected energies, the HVL values follow the order of KCNP40 < KCNP45 < KCNP50 < KCNP55 < KCNP60. The HVL of the KCNP50 sample increased from 0.996 to 2.663, 3.392, 4.351, and 5.169 cm for energies of 0.0595, 0.245, 0.444, 0.779, and 1.11 MeV, respectively. The radiation protection efficiency (RPE) results reveal that decreasing the P2O5 content in the glasses improves the radiation shielding ability of the samples. Thus, the KCNP40 sample has the best potential for photon attenuation applications.
A Silver Yarn-Incorporated Song Brocade Fabric with Enhanced Electromagnetic Shielding
Authors: Zhang Xiuling , Jin Zimin , Hu Lizhu , Zhou Xinyi , Yang Kai , Kremenakova Dana , Militky Jiri
Published: July 2021

The fabrics with electromagnetic interference (EMI) have been used in various fields. However, most studies related to the EMI fabrics focused on the improvement of the final electromagnetic shielding effectiveness (EM SE) by adjusting the preparation parameters while the breathability of the EMI fabrics was affected and the visible surficial patterns on the EMI fabric was limited. In this work, the two samples based on the Song Brocade structure were fabricated with surficial visible pattern ‘卐’. One was fabricated with silver-plated polyamide (Ag-PA) yarns and the silk yarns, the another with polyester (PET) yarns and the silk yarns. The weaving structure of the two samples were investigated by scanning electronic microscopy (SEM) and laser optical microscopy (LOM). The resistance against the EM radiation near field communication (NFC) and the ultraviolet (UV) light was also evaluated. Besides, the surface resistance, the air permeability and the water evaporation rate were investigated. The results revealed that the ‘卐’ appeared successfully on the surface of the two samples with stable weaving structure. The Ag-PA yarn-incorporated Song Brocade fabric had the EMI shielding effectiveness value around 50 dB, which was supported by the low surface resistance less than 40 Ω. The excellent NFC shielding of the Ag-PA yarn-incorporated Song Brocade was also found. The ultraviolet protection factor (UPF) value of the Ag-PA yarn-incorporated Song Brocade fabric was higher than 190. The air permeability and the evaporation rate of the Ag-PA yarn-incorporated Song Brocade fabric was higher than 99 mm/s, and 1.4 g/h, respectively. As a result, the Ag-PA yarn-incorporated Song Brocade fabrics were proposed for both the personal and the industrial scale utilization.
Facile Synthesis of Uniform Mesoporous Nb2O5 Micro-Flowers for Enhancing Photodegradation of Methyl Orange
Authors: Qiu Jian-Ping , Xie Huan-Qing , Wang Ya-Hao , Yu Lan , Wang Fang-Yuan , Chen Han-Song , Fei Zheng-Xin , Bian Chao-Qun , Mao Hui , Lian Jia-Biao
Published: July 2021

The removal of organic pollutants using green environmental photocatalytic degradation techniques urgently need high-performance catalysts. In this work, a facile one-step hydrothermal technique has been successfully applied to synthesize a Nb2O5 photocatalyst with uniform micro-flower structure for the degradation of methyl orange (MO) under UV irradiation. These nanocatalysts are characterized by transmission and scanning electron microscopies (TEM and SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) method, and UV-Vis diffuse reflectance spectroscopy (DRS). It is found that the prepared Nb2O5 micro-flowers presents a good crystal phases and consist of 3D hierarchical nanosheets with 400–500 nm in diameter. The surface area is as large as 48.6 m2 g−1. Importantly, the Nb2O5 micro-flowers exhibit superior catalytic activity up to 99.9% for the photodegradation of MO within 20 mins, which is about 60-fold and 4-fold larger than that of without catalysts (W/O) and commercial TiO2 (P25) sample, respectively. This excellent performance may be attributed to 3D porous structure with abundant catalytic active sites.
Numerical Homogenization of Multi-Layered Corrugated Cardboard with Creasing or Perforation
Authors: Garbowski Tomasz , Knitter-Piątkowska Anna , Mrówczyński Damian
Published: July 2021

The corrugated board packaging industry is increasingly using advanced numerical tools to design and estimate the load capacity of its products. This is why numerical analyses are becoming a common standard in this branch of manufacturing. Such trends cause either the use of advanced computational models that take into account the full 3D geometry of the flat and wavy layers of corrugated board, or the use of homogenization techniques to simplify the numerical model. The article presents theoretical considerations that extend the numerical homogenization technique already presented in our previous work. The proposed here homogenization procedure also takes into account the creasing and/or perforation of corrugated board (i.e., processes that undoubtedly weaken the stiffness and strength of the corrugated board locally). However, it is not always easy to estimate how exactly these processes affect the bending or torsional stiffness. What is known for sure is that the degradation of stiffness depends, among other things, on the type of cut, its shape, the depth of creasing as well as their position or direction in relation to the corrugation direction. The method proposed here can be successfully applied to model smeared degradation in a finite element or to define degraded interface stiffnesses on a crease line or a perforation line.
Corrosion Assessment of a Weathering Steel Bridge Structure after 30 Years of Service
Authors: Królikowska Agnieszka , Komorowski Leszek , Kunce Izabela , Wojda Damian , Zacharuk Katarzyna , Paszek Urszula , Wierzbicki Tomasz , Bilewska Katarzyna
Published: July 2021

The first steel with improved resistance towards atmospheric corrosion, the so-called weathering steel, was patented in the USA in 1933 and was initially used for coal railway cars, and after that, in building and bridge engineering. Weathering steels show higher corrosion resistance than carbon steels in many types of atmosphere due to their ability to form a compact, stable, adherent and protective patina during the time of exposure. Morphological evaluation of the appearance of the corrosion product layer, together with phase analysis of its components, can enable determination of the type of patina and the degree of protection of the steel. To support the visual assessment of a patina, a check based on the qualitative and quantitative phase analysis of its components may be carried out, and the PAI (Protective Ability Index) can be calculated. The estimation of the corrosion processes on original Polish-made weathering steel (12HNNbA) was carried out on a 30-year-old bridge in Poland. There are some structural problems within the deck derived not only from corrosion but also steel cracking, both inside and outside the boxes, at different heights. Fourteen representative samples of patina were analysed and their phase structures were determined by the X-ray powder diffraction method. The PAIs were determined and analysed.
The Cohomological Genus and Symplectic Genus for 4-Manifolds of Rational or Ruled Types
Authors: Dai Bo , Ho Chung-I
Published: July 2021

An important problem in low dimensional topology is to understand the properties of embedded or immersed surfaces in 4-dimensional manifolds. In this article, we estimate the lower genus bound of closed, connected, smoothly embedded, oriented surfaces in a smooth, closed, connected, oriented 4-manifold with the cohomology algebra of a rational or ruled surface. Our genus bound depends only on the cohomology algebra rather than on the geometric structure of the 4-manifold. It provides evidence for the genus minimizing property of rational and ruled surfaces.
Automatic Group Organization for Collaborative Learning Applying Genetic Algorithm Techniques and the Big Five Model
Authors: Revelo Sánchez Oscar , Collazos César A. , Redondo Miguel A.
Published: July 2021

In this paper, an approach based on genetic algorithms is proposed to form groups in collaborative learning scenarios, considering the students’ personality traits as a criterion for grouping. This formation is carried out in two stages: In the first, the information of the students is collected from a psychometric instrument based on the Big Five personality model; whereas, in the second, this information feeds a genetic algorithm that is in charge of performing the grouping iteratively, seeking for an optimal formation. The results presented here correspond to the functional and empirical validation of the approach. It is found that the described methodology is useful to obtain groups with the desired characteristics. The specific objective is to provide a strategy that makes it possible to subsequently assess in the context what type of approach (homogeneous, heterogeneous, or mixed) is the most appropriate to organize the groups.
Efficiency Analysis with Educational Data: How to Deal with Plausible Values from International Large-Scale Assessments
Authors: Aparicio Juan , Cordero Jose M. , Ortiz Lidia
Published: July 2021

International large-scale assessments (ILSAs) provide several measures as a representation of educational outcomes, the so-called plausible values, which are frequently interpreted as a representation of the ability range of students. In this paper, we focus on how this information should be incorporated into the estimation of efficiency measures of student or school performance using data envelopment analysis (DEA). Thus far, previous studies that have adopted this approach using data from ILSAs have used only one of the available plausible values or an average of all of them. We propose an approach based on the fuzzy DEA, which allows us to consider the whole distribution of results as a proxy of student abilities. To assess the extent to which our proposal offers similar results to those obtained in previous studies, we provide an empirical example using PISA data from 2015. Our results suggest that the performance measures estimated using the fuzzy DEA approach are strongly correlated with measures calculated using just one plausible value or an average measure. Therefore, we conclude that the studies that decide upon using one of these options do not seem to be making a significant error in their estimates.
From Teacher of Nations to Teacher of Mathematics
Authors: Hošpesová Alena , Novotná Jarmila , Vondrová Naďa , Moraová Hana , Tichá Marie
Published: July 2021

The article provides an overview of research focusing on pre- and in-service teacher education, conducted in the Czech Republic by teams of researchers of which the authors were members. It employs the methodology of a qualitative meta-analysis of studies aimed at distinguishing key areas of research and their main results. Twenty-one studies were analyzed, 11 of which targeted pre-service teachers and 10 in-service teachers. The article briefly describes the historical and cultural context that informs mathematics education in the Czech Republic. It also elaborates on key theoretical concepts shared by the studies analyzed, including teachers’ pedagogical content knowledge, competence and pedagogical reflection. The meta-analysis uncovered a common core of the studies in their focus on the process of professionalization for mathematics teachers in its three dimensions: professional vision, professional knowledge, and professional action. Six core research strands are identified within the group of studies: lesson study as a means of developing teachers’ pedagogical content knowledge; joint reflection; professional vision and its development; culture of problem solving and teacher development; problem posing to support subject-didactic competence and teachers’ competencies for content and language integrated learning and culturally responsive teaching. The article outlines the methodology and main results of the studies in each research strand and discusses their implications. Finally based on the meta-analysis, a discussion of the core concepts of teacher reflection, problem solving and problem posing is developed.