bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Urease Inhibitor of Ruminal Microbiota Screened through Molecular Docking
Authors: Zhang Zhenyu , Li Ming , Zhang Xiaoyin , Zheng Nan , Zhao Shengguo , Wang Jiaqi
Published: August 2020

Inhibition of the urease activity of ruminal microbiota is not only beneficial for increasing dietary and endogenic urea-N utilization efficiency in ruminants but also might be applicable for the preservation of nitrogen fertilizer in soil and treatment of gastrointestinal and urinary tract infections caused by ureolytic bacteria. To discover urease inhibitors to efficiently target ruminal microbiota, the identified ruminal microbial metagenomic urease gene was used to construct a homology model to virtually screen urease inhibitors from the ChemDiv database by molecular docking. The GMQE and QMEAN values of the homology model were 0.85 and −0.37, respectively, indicating a good model quality. The inhibition effect of the screened urease inhibitor for ruminal urea degradation was assessed by ruminal microbial fermentation in vitro. The toxic effect of the candidate inhibitor was performed using gut Caco-2 cells in vitro. The results showed that compound 3-[1-[(aminocarbonyl)amino]-5-(4-methoxyphenyl)-1H-pyrrol-2-yl] propanoic acid (ChemDiv_ID: 6238-0047, IC50 = 65.86 μM) was found to be the most effective urease inhibitor among the candidate compounds. Compound 6238-0047 significantly lowered the amount of urea degradation and ammonia production in ruminal microbial fermentation. The 24 h degradation rate of compound 6238-0047 in ruminal microbial fermentation was 3.32%–16.00%. In addition, compound 6238-0047 (10–100 μM) had no significant adverse effect on the cell viability of Caco-2 cells. Molecular docking showed that compound 6238-0047 could interact with Asp359 in the active site and Cys318 in the flap region by the hydrogen bond and Pi-Alkyl interaction, respectively. Compound 6238-0047 could be used as a novel inhibitor for decreasing the urease activity of ruminal microbiota.
A 47-Year Comparison of Lower Body Muscular Power in Spanish Boys: A Short Report
Authors: Chulvi-Medrano Iván , Pombo Manuel , Saavedra-García Miguel Ángel , Rebullido Tamara Rial , Faigenbaum Avery D
Published: August 2020

Much of the evidence examining temporal trends in fitness among youth has found a decrease in measures of muscular strength and muscular power over recent decades. The aim of this study was to examine trends in lower body muscular power in Spanish boys over 47 years. In 1969 140 boys (10–11 years; body mass index = 19.24, SD = 2.91 kg/m2) and in 2016, 113 boys (10–11 years; body mass index = 19.20, SD = 3.15 kg/m2) were recruited. Lower body power was assessed using the vertical jump (VJ) and standing long jump (SLJ) tests. Significant differences and a large effect size were shown between groups in the SLJ (p = 0.001; d = 0.94) and the VJ (p = 0.001; d = 0.66). SLJ data in 1969 were higher (1.52 m, SD = 0.19) when compared to the 2016 data (1.34 m, SD = 0.18). The VJ performance of the 1969 sample was also higher (25.95 cm; SD = 6.58) than the 2016 sample (21.56 cm; SD = 4.72). SLJ and VJ performance of the 2016 group decreased 11.8% and 16.9%, respectively. There were no significant differences between groups in body mass index. The results indicate a secular decline in lower body muscular power in 10–11-year-old Spanish boys with no significant changes in body mass index over the 47-year study period.
Volatility-Adjusted 60/40 versus 100—New Risk Investing Paradigm
Authors: Liew Jim Kyung-Soo , Ajakh Ahmad
Published: August 2020

In this study we examine the volatility-adjusted 60/40 rule at the individual company level. We document that strong diversification benefits exist over the long-term, and that both the equity and corporate bonds exhibit positive expected drifts. For our sample of 30 large-cap companies, given that corporate bond positions have shown less volatility than the equity position, we leveraged the resultant portfolio of 60/40 to match that of the equity position. When we compare the two investments, we document an outperformance of 100 to 200 bps per year, even after we account for the leverage costs of 100 bps. We believe our work will open up a new risk investing paradigm for those seeking long-term advantages.
Microstructure Characteristics and Its Effect on the Fracture in the Triple Junction Region of Friction Stir Welded Mg Alloys Subjected to Tension
Authors: Liu Guodong , Yang Qunying , Cheng Yongshan
Published: August 2020

Because of the tensile strength decreasing of the friction stir welded wrought magnesium (Mg) alloy compared to the base material, the reasons for the failure of weld has been focused on. After the fracture in transverse tension, the crack went through the welded joint from the center of the weld to the transition zone between the thermal-mechanical affected zone and weld zone. In the present study, the microstructure characteristics and its effect on the facture in the triple junction region is investigated. Based on the metallography and the electron back-scattered diffraction (EBSD) technology, it was observed that a twin band extended from the triple junction region to the middle of weld. The profuse twinning in the twin band was considered to play an important role on the crack propagation from the stir zone edge to the crown zone.
A New Approach to the Fabrication of Memristive Neuromorphic Devices: Compositionally Graded Films
Authors: Yoon Jong-Gul
Published: August 2020

Energy-efficient computing paradigms beyond conventional von-Neumann architecture, such as neuromorphic computing, require novel devices that enable information storage at nanoscale in an analogue way and in-memory computing. Memristive devices with long-/short-term synaptic plasticity are expected to provide a more capable neuromorphic system compared to traditional Si-based complementary metal-oxide-semiconductor circuits. Here, compositionally graded oxide films of Al-doped MgxZn1−xO (g-Al:MgZnO) are studied to fabricate a memristive device, in which the composition of the film changes continuously through the film thickness. Compositional grading in the films should give rise to asymmetry of Schottky barrier heights at the film-electrode interfaces. The g-Al:MgZnO films are grown by using aerosol-assisted chemical vapor deposition. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the films show self-rectifying memristive behaviors which are dependent on maximum applied voltage and repeated application of electrical pulses. Endurance and retention performance tests of the device show stable bipolar resistance switching (BRS) with a short-term memory effect. The short-term memory effects are ascribed to the thermally activated release of the trapped electrons near/at the g-Al:MgZnO film-electrode interface of the device. The volatile resistive switching can be used as a potential selector device in a crossbar memory array and a short-term synapse in neuromorphic computing.
Wear Resistance Enhancement of Al6061 Alloy Surface Layer by Laser Dispersed Carbide Powders
Authors: Jendrzejewski Rafał , Łubiński Jacek , Śliwiński Gerard
Published: August 2020

In this paper, results of the experimental study on improving wear resistance in sliding friction of Al-based alloy are presented. The technique used involves the formation of a metal matrix composite (MMC) in the alloy surface layer by laser dispersion of carbide powders such as WC, TiC and SiC. For WC and TiC MMC surface coatings fabricated under conditions typical for most of the technologically relevant solid-state lasers (wavelength range of 0.8–1.1 μm), the nearly inversely proportional dependence of the required laser energy density on the powder mass density is observed. Highly homogenous distribution of powder particle content (up to 40%) in the MMC surface coatings of a thickness between 0.8 and 1.6 mm obtained by multiple scanning is observed in the cross-section of specimens processed within a rather narrow parameter window. Tribological tests and comparison to untreated material reveal wear resistance increases by five- and ten-fold, observed in samples with laser-dispersed TiC and WC powders, respectively. Results indicate that substantial modification and reinforcement of the surface layer can be achieved in Al alloy in a one-step process without substrate preheating.
Focused Update on Pulmonary Hypertension in Children—Selected Topics of Interest for the Adult Cardiologist
Authors: Albinni Sulaima , Marx Manfred , Lang Irene M.
Published: August 2020

Pulmonary hypertensive vascular disease (PHVD), and pulmonary hypertension (PH), which is a broader term, are severe conditions associated with high morbidity and mortality at all ages. Treatment guidelines in childhood are widely adopted from adult data and experience, though big differences may exist regarding aetiology, concomitant conditions and presentation. Over the past few years, paediatric aspects have been incorporated into the common guidelines, which currently address both children and adults with pulmonary hypertension (PH). There are multiple facets of PH in the context of cardiac conditions in childhood. Apart from Eisenmenger syndrome (ES), the broad spectrum of congenital heart disease (CHD) comprises PH in failing Fontan physiology, as well as segmental PH. In this review we provide current data and novel aspects on the pathophysiological background and individual management concepts of these conditions. Moreover, we focus on paediatric left heart failure with PH and its challenging issues, including end stage treatment options, such as mechanical support and paediatric transplantation. PH in the context of rare congenital disorders, such as Scimitar Syndrome and sickle cell disease is discussed. Based on current data, we provide an overview on multiple underlying mechanisms of PH involved in these conditions, and different management strategies in children and adulthood. In addition, we summarize the paediatric aspects and the pros and cons of the recently updated definitions of PH. This review provides deeper insights into some challenging conditions of paediatric PH in order to improve current knowledge and care for children and young adults.
Recent Advances in Liposome-Based Molecular Robots
Authors: Shoji Kan , Kawano Ryuji
Published: August 2020

A molecular robot is a microorganism-imitating micro robot that is designed from the molecular level and constructed by bottom-up approaches. As with conventional robots, molecular robots consist of three essential robotics elements: control of intelligent systems, sensors, and actuators, all integrated into a single micro compartment. Due to recent developments in microfluidic technologies, DNA nanotechnologies, synthetic biology, and molecular engineering, these individual parts have been developed, with the final picture beginning to come together. In this review, we describe recent developments of these sensors, actuators, and intelligence systems that can be applied to liposome-based molecular robots. First, we explain liposome generation for the compartments of molecular robots. Next, we discuss the emergence of robotics functions by using and functionalizing liposomal membranes. Then, we discuss actuators and intelligence via the encapsulation of chemicals into liposomes. Finally, the future vision and the challenges of molecular robots are described.
Papaya Fruit Pulp and Resulting Lactic Fermented Pulp Exert Antiviral Activity against Zika Virus
Authors: Haddad Juliano G. , Carcauzon Victoria , El Kalamouni Omar , Desprès Philippe , Garcia Cyrielle , Remize Fabienne , El Kalamouni Chaker
Published: August 2020

There are a several emerging and re-emerging RNA viruses that are prevalent around the world for which there are no licensed vaccines or antiviral drugs. Zika virus (ZIKV) is an example of an emerging virus that has become a significant concern worldwide because of its association with severe congenital malformations and neurological disorders in adults. Several polyphenol-rich extracts from plants were used as nutraceuticals which exhibit potent in vitro antiviral effects. Here, we demonstrated that the papaya pulp extracted from Carica papaya fruit inhibits the infection of ZIKV in human cells without loss of cell viability. At the non-cytotoxic concentrations, papaya pulp extract has the ability to reduce the virus progeny production in ZIKV-infected human cells by at least 4-log, regardless of viral strains tested. Time-of-drug-addition assays revealed that papaya pulp extract interfered with the attachment of viral particles to the host cells. With a view of preserving the properties of papaya pulp over time, lactic fermentation based on the use of bacterial strains Weissella cibaria 64, Lactobacillus plantarum 75 and Leuconostoc pseudomesenteroides 56 was performed and the resulting fermented papaya pulp samples were tested on ZIKV. We found that lactic fermentation of papaya pulp causes a moderate loss of antiviral activity against ZIKV in a bacterial strain-dependent manner. Whereas IC50 of the papaya pulp extract was 0.3 mg/mL, we found that fermentation resulted in IC50 up to 4 mg/mL. We can conclude that papaya pulp possesses antiviral activity against ZIKV and the fermentation process has a moderate effect on the antiviral effect.
A Novel Small Molecule, 1,3-di-m-tolyl-urea, Inhibits and Disrupts Multispecies Oral Biofilms
Authors: Kalimuthu Shanthini , Cheung Becky P.K. , Yau Joyce Y.Y. , Shanmugam Karthi , Solomon Adline Princy , Neelakantan Prasanna
Published: August 2020

An imbalance of homeostasis between the microbial communities and the host system leads to dysbiosis in oral micro flora. DMTU (1,3-di-m-tolyl-urea) is a biocompatible compound that was shown to inhibit Streptococcus mutans biofilm by inhibiting its communication system (quorum sensing). Here, we hypothesized that DMTU is able to inhibit multispecies biofilms. We developed a multispecies oral biofilm model, comprising an early colonizer Streptococcus gordonii, a bridge colonizer Fusobacterium nucleatum, and late colonizers Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. We performed comprehensive investigations to demonstrate the effect of DMTU on planktonic cells and biofilms. Our findings showed that DMTU inhibits and disrupts multispecies biofilms without bactericidal effects. Mechanistic studies revealed a significant down regulation of biofilm and virulence-related genes in P. gingivalis. Taken together, our study highlights the potential of DMTU to inhibit polymicrobial biofilm communities and their virulence.
A Review: The Triterpenoid Saponins and Biological Activities of Lonicera Linn.
Authors: Fang Zhongying , Li Jia , Yang Ran , Fang Lei , Zhang Yongqing
Published: August 2020

Lonicera Linn. is an important genus of the family Caprifoliaceae comprising of approximately 200 species, and some species of which have been usually used in traditional Chinese medicine for thousands of years. Some species of this genus can also be used in functional foods, cosmetics and other applications. The saponins, as one of most important bioactive components of the Lonicera Linn. genus, have attracted the attention of the scientific community. Thus, a comprehensive and systematic review on saponins from the genus is indispensable. In this review, 87 saponins and sapogenin from the genus of Lonicera Linn., together with their pharmacological activities including hepatoprotective, anti-inflammatory, anti-bacterial, anti-allergic, anti-tumor, and immunomodulatory effects, and hemolytic toxicity were summarized.
Detection of Biomarkers Relating to Quality and Differentiation of Some Commercially Significant Whole Fish Using Spatially Off-Set Raman Spectroscopy
Authors: Landry Jeremy D. , Torley Peter J. , Blanch Ewan W.
Published: August 2020

Aquaculture represents a major part of the world’s food supply. This area of food production is developing rapidly, and as such the tools and analytical techniques used to monitor and assess the quality of fish need to also develop and improve. The use of spatially off-set Raman spectroscopy (SORS) is particularly well-suited for these applications, given the ability of this technique to take subsurface measurements as well as being rapid, non-destructive and label-free compared to classical chemical analysis techniques. To explore this technique for analysing fish, SORS measurements were taken on commercially significant whole fish through the skin in different locations. The resulting spectra were of high quality with subsurface components such as lipids, carotenoids, proteins and guanine from iridophore cells clearly visible in the spectra. These spectral features were characterised and major bands identified. Chemometric analysis additionally showed that clear differences are present in spectra not only from different sections of a fish but also between different species. These results highlight the potential application for SORS analysis for rapid quality assessment and species identification in the aquaculture industry by taking through-skin measurements.
Gel Synthesis of Hexaferrites Pb1−xLaxFe12−xZnxO19 and Properties of Multiferroic Composite Ceramics PZT–Pb1−xLaxFe12−xZnxO19
Authors: Lisnevskaya Inna V. , Aleksandrova Inga A.
Published: August 2020

We investigated the opportunities for obtaining hexaferrites Pb1−xLaxFe12−xZnxO19 (x = 0–1) from citrate–glycerin gel and showed that synthesis occurs via the formation of the Fe3O4 phase; products with a small amount of hematite impurity Fe2O3 can be obtained after firing at 800 to 900 °C with 0 ≤ x ≤ 0.5. If x > 0.5, perovskite-like LaFeO3 is formed in samples, so that if x = 0.9–1, the synthesis products virtually do not contain phases with hexaferrite structures and represent a mixture of LaFeO3, Fe2O3, and Fe3O4. Within the range of 0 ≤ x ≤ 0.5, the electrical and magnetic characteristics of hexaferrites Pb1−xLaxFe12−xZnxO19 are slightly dependent on x and have the following average values: A relative permittivity ε/ε0 ~ 45, a dielectric loss tangent tan δ ~ 0.6, an electrical resistivity R ~ 109 Ohm cm, coercivity Hc ~ 3 kOe, saturation magnetization Ms ~ 50 emu/g, and remanent magnetization Mr ~ 25 emu/g. The magnetoelectric (ME) ceramics 50 wt.% PZTNB-1 + 50 wt.% Pb1−xLaxFe12−xZnxO19 (PZTNB-1 is an industrial piezoelectric material based on lead titanate zirconate (PZT) do not contain impurity phases and have the following characteristics: Piezoelectric coefficients d33 = 10–60 and −d31 = 2–30 pC/N, piezoelectric voltage coefficients g33 = 2–13 and −g31 = 1–5 mV m/N, an electromechanical coupling coefficient Kp = 0.03–0.13, magnetic parameters Hc = 3–1 kOe, Ms = 50–30, and Mr = 25–12 emu/g. The maximum ME coupling coefficient ΔE/ΔH ~ 1.75 mV/(cm Oe) was achieved with x = 0.5.
Prevalence and Social Determinants of Food Insecurity among College Students during the COVID-19 Pandemic
Authors: Owens Meghan R. , Brito-Silva Francilia , Kirkland Tracie , Moore Carolyn E. , Davis Kathleen E. , Patterson Mindy A. , Miketinas Derek C. , Tucker Wesley J.
Published: August 2020

The coronavirus disease (COVID-19) pandemic has increased unemployment and food insecurity in the United States (US). Prior to the pandemic, college students exhibited higher rates of food insecurity than nonstudent households. The objectives of this study were to assess the prevalence and determinants of food insecurity among college students during the COVID-19 pandemic. We administered an online survey to 651 students on three diverse campuses at a state-funded university in Texas, US, in May 2020. Food security was assessed using a multistep approach that included the 2-item Food Sufficiency Screener and 6-Item USDA Food Security Survey Module (FSSM). Overall, 34.5% of respondents were classified as food insecure within the last 30 days. The strongest predictors of food insecurity were change in current living arrangement (OR = 2.70, 95% CI: 2.47, 2.95), being furloughed (OR = 3.22, 95% CI: 2.86, 3.64), laid off (OR = 4.07, 95% CI: 3.55, 4.66), or losing part-time work (OR = 5.73, 95% CI: 5.09, 6.46) due to the COVID-19 pandemic. These findings highlight the high prevalence of food insecurity among college students during the COVID-19 pandemic, with students who experienced housing insecurity and/or loss of income due to the pandemic being impacted the most.
Hip Fracture Patients in Geriatric Rehabilitation Show Poor Nutritional Status, Dietary Intake and Muscle Health
Authors: Groenendijk Inge , Kramer Charlotte S. , den Boeft Laura M. , Hobbelen Hans S. M. , van der Putten Gert-Jan , de Groot Lisette C. P. G. M.
Published: August 2020

The aim of this study was to gain insight into the nutritional status, dietary intake and muscle health of older Dutch hip fracture patients to prevent recurrent fractures and to underpin rehabilitation programs. This cross-sectional study enrolled 40 hip fracture patients (mean ± SD age 82 ± 8.0 years) from geriatric rehabilitation wards of two nursing homes in the Netherlands. Assessments included nutritional status (Mini Nutritional Assessment), dietary intake on three non-consecutive days which were compared with Dietary Reference Intake values, and handgrip strength. Muscle mass was measured using Bioelectrical Impedance Analysis and ultrasound scans of the rectus femoris. Malnutrition or risk of malnutrition was present in 73% of participants. Mean energy, protein, fibre and polyunsaturated fat intakes were significantly below the recommendations, while saturated fat was significantly above the UL. Protein intake was <0.8 in 46% and <1.2 g/(kg·day) in 92%. Regarding micronutrients, mean intakes of calcium, vitamin D, potassium, magnesium and selenium were significantly below the recommendations. The prevalence of low muscle mass, low handgrip strength and sarcopenia were 35%, 27% and 10%, respectively. In conclusion, a poor nutritional status, dietary intake and muscle health are common in older hip fracture patients in geriatric rehabilitation wards.
Development and Characterization of Inkjet Printed Edible Films for Buccal Delivery of B-Complex Vitamins
Authors: Eleftheriadis Georgios , Monou Paraskevi Kyriaki , Andriotis Eleftherios , Mitsouli Elisavet , Moutafidou Nikoleta , Markopoulou Catherine , Bouropoulos Nikolaos , Fatouros Dimitrios
Published: August 2020

Buccal films containing two vitamins, i.e., thiamine hydrochloride (THCl) and nicotinic acid (NA), were fabricated via two-dimensional (2D) inkjet printing. For the preparation of buccal films, solubility studies and rheological evaluations were conducted in distilled water and propylene-glycol (PG) as main solvent and viscosity/surface tension modifier, respectively. The increased solubility in the solvents’ mixture indicated that manufacturing of several doses of the THCl and NA is achievable. Various doses were deposited onto sugar-sheet substrates, by increasing the number of printing passes. The physiochemical characterization (SEM, DSC, FTIR) revealed that inkjet printing does not affect the solid state of the matrix. Water uptake studies were conducted, to compare the different vitamin-loaded formulations. The in vitro release studies indicated the burst release of both vitamins within 10 min, a preferable feature for buccal administration. The in vitro permeation studies indicated that higher concentrations of the vitamins onto the sugar sheet improved the in vitro permeation performance of printed formulations.
Population Pharmacokinetics of Continuous-Infusion Meropenem in Febrile Neutropenic Patients with Hematologic Malignancies: Dosing Strategies for Optimizing Empirical Treatment against Enterobacterales and P. aeruginosa
Authors: Cojutti Pier Giorgio , Candoni Anna , Lazzarotto Davide , Filì Carla , Zannier Maria , Fanin Renato , Pea Federico
Published: August 2020

A population pharmacokinetic analysis of continuous infusion (CI) meropenem was conducted in a prospective cohort of febrile neutropenic (FN) patients with hematologic malignancies. A non-parametric approach with Pmetrics was used for pharmacokinetic analysis and covariate evaluation. Monte Carlo simulations were performed for identifying the most appropriate dosages for empirical treatment against common Enterobacterales and P. aeruginosa. The probability of target attainment (PTA) of steady-state meropenem concentration (Css)-to-minimum inhibitory concentration (MIC) ratio (Css/MIC) ≥1 and ≥4 at the European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoint of 2 mg/L were calculated. Cumulative fraction of response (CFR) against Enterobacterales and P. aeruginosa were assessed as well. PTAs and CFRs ≥ 90% were considered optimal. A total of 61 patients with 178 meropenem Css were included. Creatinine clearance (CLCR) was the only covariate associated with meropenem clearance. Monte Carlo simulations showed that dosages of meropenem ranging between 1 g q8h and 1.25 g q6h by CI may grant optimal PTAs of Css/MIC ≥4 at the EUCAST clinical breakpoint. Optimal CFRs may be granted with these dosages against the Enterobacterales at Css/MIC ≥ 4 and against P. aeruginosa at Css/MIC ≥ 1. When dealing against P. aeruginosa at Css/MIC ≥ 4, only a dosage of 1.5 g q6h by CI may grant quasi-optimal CFR (around 80–87%). In conclusion, our findings suggest that dosages of meropenem ranging between 1 g q8h and 1.25 g q6h by CI may maximize empirical treatment against Enterobacterales and P. aeruginosa among FN patients with hematologic malignancies having different degree of renal function.
Fabrication of ZnO Nanoparticle-Decorated Nanofiber Mat with High Uniformity Protected by Constructing Tri-Layer Structure
Authors: Phan Duy-Nam , Choi Hyeong Yeol , Oh Seong-Geun , Kim Myungwoong , Lee Hoik
Published: August 2020

We demonstrate a sequential electrospinning process involving the adsorption of ZnO nanoparticles on the surface of bio-based polyester, which is a terpolyester of a renewable isosorbide (ISB) monomer, ethylene glycol, 1,4-cyclohexane dimethanol, and terephthalic acid, the-so-called PEICT, to fabricate stable ZnO nanoparticles/PEICT nanofiber composite system protected with other two PEICT nanofiber mats. We found that post-electrospinning treatment with a particular solvent was effective to remove a residual solvent molecule in the PEICT nanofibers, which induced significant aggregation of the nanoparticles, leading to non-uniform distribution of the particles on the surface. Sequential electrospinning of the PEICT solution to sandwich ZnO nanoparticle-decorated PEICT nanofiber mat enabled to attain protected the inorganic/organic hybrid nanofiber mat, improving the long-term stability, and the reproducibility of the inorganic particles decorated nanofiber fabrication.
Recent Progress in the Development of Composite Membranes Based on Polybenzimidazole for High Temperature Proton Exchange Membrane (PEM) Fuel Cell Applications
Authors: Escorihuela Jorge , Olvera-Mancilla Jessica , Alexandrova Larissa , del Castillo L. Felipe , Compañ Vicente
Published: August 2020

The rapid increasing of the population in combination with the emergence of new energy-consuming technologies has risen worldwide total energy consumption towards unprecedent values. Furthermore, fossil fuel reserves are running out very quickly and the polluting greenhouse gases emitted during their utilization need to be reduced. In this scenario, a few alternative energy sources have been proposed and, among these, proton exchange membrane (PEM) fuel cells are promising. Recently, polybenzimidazole-based polymers, featuring high chemical and thermal stability, in combination with fillers that can regulate the proton mobility, have attracted tremendous attention for their roles as PEMs in fuel cells. Recent advances in composite membranes based on polybenzimidazole (PBI) for high temperature PEM fuel cell applications are summarized and highlighted in this review. In addition, the challenges, future trends, and prospects of composite membranes based on PBI for solid electrolytes are also discussed.
Analytical Modeling of the Postcracking Response Observed in Hybrid Steel/Polypropylene Fiber-Reinforced Concrete
Authors: Caggiano Antonio , Pepe Marco , Xargay Hernan , Martinelli Enzo
Published: August 2020

This study deals with the analytical modeling of hybrid fiber-reinforced concretes (HyFRCs) made with a blend of different types of fibers characterized by different geometries and/or constitutive materials. The presented analytical formulation is oriented towards predicting the postcracking behavior of HyFRC and is mainly based on the well-known “cracked-hinge” model originally employed for standard fiber-reinforced concrete beams. The proposed model is validated by considering the experimental results obtained in a previous study carried out on HyFRCs mixtures made with a blend of steel and polypropylene fibers. Theoretical results are presented to demonstrate the predictive capabilities of the model to simulate the observed experimental behavior. The model performance is in very good agreement with the experimental data. Therefore, it has the capability to forecast the postcracking behavior of a generic HyFRC of given fiber contents depending on the actual proportion of the fiber blend. Finally, the proposed formulation can be applied as a computational aid to the design of HyFRC mixtures for structural purposes.
A Method to Automatically Detect Changes in Multitemporal Spectral Indices: Application to Natural Disaster Damage Assessment
Authors: Pulvirenti Luca , Squicciarino Giuseppe , Fiori Elisabetta
Published: August 2020

This paper presents a new method, based on clustering and thresholding, to automatically perform binary change detection in multitemporal spectral indices. The method is denoted as Buffer-From-Cluster Approach (BFCA). To estimate the distributions of changed and unchanged pixels, as needed for the purpose of a reliable thresholding of a spectral index, a clustering algorithm is preliminarily applied to identify image objects possibly corresponding to areas where significant changes occurred. Then, a buffer zone is created around the selected cluster to identify unchanged areas surrounding changed ones. The cluster and the buffer zone are jointly analyzed to estimate the distributions of changed and unchanged pixels and to verify that they can be distinguished from each other. Finally, the results of thresholding and clustering are combined to generate the binary change map. The BFCA has been conceived to map the extent of the areas affected by a natural disaster like wildfire. To validate the proposed method, burned area maps produced by applying the BFCA to spectral indices derived from Sentinel-2 data have been compared to maps produced by the Copernicus Emergency Management Service. For testing the multi-hazard detection capability, the same kind of exercise has been carried out for a flooding test case too. The positive results of the comparison have confirmed the effectiveness of the proposed method.
Flash Flood Susceptibility Modeling and Magnitude Index Using Machine Learning and Geohydrological Models: A Modified Hybrid Approach
Authors: Elmahdy Samy , Ali Tarig , Mohamed Mohamed
Published: August 2020

In an arid region, flash floods (FF), as a response to climate changes, are the most hazardous causing massive destruction and losses to farms, human lives and infrastructure. A first step towards securing lives and infrastructure is the susceptibility mapping and predicting of occurrence sites of FF. Several studies have been applied using an ensemble machine learning model (EMLM) but measuring FF magnitude using a hybrid approach that integrates machine learning (MCL) and geohydrological models have not been widely applied. This study aims to modify a hybrid approach by testing three machine learning models. These are boosted regression tree (BRT), classification and regression trees (CART), and naive Bayes tree (NBT) for FF susceptibility mapping at the northern part of the United Arab Emirates (NUAE). This is followed by applying a group of accuracy metrics (precision, recall and F1 score) and the receiving operating characteristics (ROC) curve. The result demonstrated that the BRT has the highest performance for FF susceptibility mapping followed by the CART and NBT. After that, the produced FF map using the BRT was then modified by dividing it into seven basins, and a set of new FF conditioning parameters namely alluvial plain width, basin gradient and mean slope for each basin was calculated for measuring FF magnitude. The results showed that the mountainous and narrower basins (e.g., RAK, Masafi, Fujairah, and Rol Dadnah) have the highest probability occurrence of FF and FF magnitude, while the wider alluvial plains (e.g., Al Dhaid) have the lowest probability occurrence of FF and FF magnitude. The proposed approach is an effective approach to improve the susceptibility mapping of FF, landslides, land subsidence, and groundwater potentiality obtained using ensemble machine learning, which is used widely in the literature.
Retrieval of Ocean Surface Wind Speed Using Reflected BPSK/BOC Signals
Authors: Wang Hao-Yu , Juang Jyh-Ching
Published: August 2020

The Global Navigation Satellite System (GNSS) has become a valuable resource as a remote sensing technique. In the past decade, the use of reflected GNSS signals for sensing the Earth, also known as GNSS reflectometry (GNSS-R), has grown rapidly. On the other hand, with the continuous development of GNSS, multi-frequency multi-modulation signals have been used to enhance not only positioning performance, but also remote sensing applications. It is known that for some constellations, navigation satellites broadcast signals employing BPSK (binary phase-shift keying) modulation and BOC (binary offset carrier) modulation at the same frequency band. This paper proposes a new GNSS-R measurement, called a composite delay-Doppler map (cDDM), by utilizing the received reflected GNSS signals with different modulation techniques for the purpose of retrieving wind speed. The GNSS-R receiver can receive BPSK and BOC signals simultaneously at the same frequency band (e.g., GPS III L1 C/A and L1C or QZSS L1 C/A and L1C) and process the signals to generate GNSS-R measurements. Exploration of the observable features extracted from the composite DDM and the wind speed retrieval algorithm are also provided. The simulation verifies the proposed method under a configuration that is specified for the orbital and instrument specification of the upcoming TRITON mission.
ZnO ALD-Coated Microsphere-Based Sensors for Temperature Measurements
Authors: Listewnik Paulina , Bechelany Mikhael , Jasinski Jacek B. , Szczerska Małgorzata
Published: August 2020

In this paper, the application of a microsphere-based fiber-optic sensor with a 200 nm zinc oxide (ZnO) coating, deposited by the Atomic Layer Deposition (ALD) method, for temperature measurements between 100 and 300 °C, is presented. The main advantage of integrating a fiber-optic microsphere with a sensing device is the possibility of monitoring the integrity of the sensor head in real-time, which allows for higher accuracy during measurements. The study has demonstrated that ZnO ALD-coated microsphere-based sensors can be successfully used for temperature measurements. The sensitivity of the tested device was found to be 103.5 nW/°C when the sensor was coupled with a light source of 1300 nm central wavelength. The measured coefficient R2 of the sensor head was over 0.99, indicating a good fit of the theoretical linear model to the measured experimental data.
Research on Airplane and Ship Detection of Aerial Remote Sensing Images Based on Convolutional Neural Network
Authors: Cao Changqing , Wu Jin , Zeng Xiaodong , Feng Zhejun , Wang Ting , Yan Xu , Wu Zengyan , Wu Qifan , Huang Ziqiang
Published: August 2020

The wide range, complex background, and small target size of aerial remote sensing images results in the low detection accuracy of remote sensing target detection algorithms. Traditional detection algorithms have low accuracy and slow speed, making it difficult to achieve the precise positioning of small targets. This paper proposes an improved algorithm based on You Only Look Once (YOLO)-v3 for target detection of remote sensing images. Due to the difficulty in obtaining the datasets, research on small targets for complex images, such as airplanes and ships, is the focus of research. To make up for the problem of insufficient data, we screen specific types of training samples from the DOTA (Dataset of Object Detection in Aerial Images) dataset and select small targets in two different complex backgrounds of airplanes and ships to jointly evaluate the optimization degree of the improved network. We compare the improved algorithm with other state-of-the-art target detection algorithms. The results show that the performance indexes of both datasets are ameliorated by 1–3%, effectively verifying the superiority of the improved algorithm.
A Fast 3D Near Range Imaging Algorithm for a Scanning Sparse MIMO Array in the Millimeter Band
Authors: Wang Feifan , Deng Bin , Yang Qi , Wang Hongqiang , Zhang Ye
Published: August 2020

Millimeter-wave technology has been widely used in near range targets imaging scenarios, such as mechanical scanning and multiple input multiple output (MIMO) array imaging. Emerging scanning array regimes increase the need for fast-speed and high-quality imaging techniques, which, however, are often subject to specific array positions. Moreover, the relationship between array positions and the imaging performance is not clear, which leads to no uniform standard for array design. In this paper, a series of array configurations are designed to explore the impact of different array positions on the cross-range imaging performance. Meanwhile, a novel fast fully focused imaging algorithm with wavenumber domain properties is presented, which is not constrained by the positions of the transmitters and receivers. Simulation and experimental results show that, compared with a conventional algorithm, the proposed algorithm has a faster imaging speed under the same imagining quality. This study provides a feasible method for fast fully focused imaging in the case of location-constrained MIMO arrays, or partially damaged transceivers.
Estimation of the Structural and Geomechanical Anisotropy in Fault Gouges Using 3D Micro-Computed Tomography (μ-CT)
Authors: Yang Eomzi , Yun Tae Sup , Kim Kwang Yeom , Moon Seong Woo , Seo Yong-Seok
Published: August 2020

Fault gouges play an important role in the shear deformation of fault zones, by causing weakness and frictional instability in structures. Previous studies have investigated the evolution of shear deformation of fault zones by observing experiments using remolded and synthetic gouge specimens at a micro-scale. However, how the spatial configuration of the rock constituents accounts for the 3D anisotropy of intact structures of fault gouges, particularly at the core-scale, is not well understood. We obtained 3D μ-CT images of directionally cored gouge specimens and performed statistical analysis to quantify the major orientation of the internal structures. Direct shear tests were conducted to investigate the relationship between the distribution of the internal structures and geomechanical behavior. The results show that the undisturbed fault gouge has a clear anisotropy parallel to the fault plane even at the core-scale. Moreover, the direct shear test results show that the frictional resistance of a fault gouge has anisotropy related to the fault plane. The simple, yet robust method proposed in this study confirms that the core-scale structural anisotropy is correlated to the anisotropic shear resistance.
Fully-Actuated Aerial Manipulator for Infrastructure Contact Inspection: Design, Modeling, Localization, and Control
Authors: Sanchez-Cuevas Pedro J. , Gonzalez-Morgado Antonio , Cortes Nicolas , Gayango Diego B. , Jimenez-Cano Antonio E. , Ollero Aníbal , Heredia Guillermo
Published: August 2020

This paper presents the design, modeling and control of a fully actuated aerial robot for infrastructure contact inspection as well as its localization system. Health assessment of transport infrastructure involves measurements with sensors in contact with the bridge and tunnel surfaces and the installation of monitoring sensing devices at specific points. The design of the aerial robot presented in the paper includes a 3DoF lightweight arm with a sensorized passive joint which can measure the contact force to regulate the force applied with the sensor on the structure. The aerial platform has been designed with tilted propellers to be fully actuated, achieving independent attitude and position control. It also mounts a “docking gear” to establish full contact with the infrastructure during the inspection, minimizing the measurement errors derived from the motion of the aerial platform and allowing full contact with the surface regardless of its condition (smooth, rough, ...). The localization system of the aerial robot uses multi-sensor fusion of the measurements of a topographic laser sensor on the ground and a tracking camera and inertial sensors on-board the aerial robot, to be able to fly under the bridge deck or close to the bridge pillars where GNSS satellite signals are not available. The paper also presents the modeling and control of the aerial robot. Validation experiments of the localization system and the control system, and with the aerial robot inspecting a real bridge are also included.
An Improved FBPN-Based Detection Network for Vehicles in Aerial Images
Authors: Wang Bin , Gu Yinjuan
Published: August 2020

With the development of artificial intelligence and big data analytics, an increasing number of researchers have tried to use deep-learning technology to train neural networks and achieved great success in the field of vehicle detection. However, as a special domain of object detection, vehicle detection in aerial images still has made limited progress because of low resolution, complex backgrounds and rotating objects. In this paper, an improved feature-balanced pyramid network (FBPN) has been proposed to enhance the network’s ability to detect small objects. By combining FBPN with modified faster region convolutional neural network (faster-RCNN), a vehicle detection framework for aerial images is proposed. The focal loss function is adopted in the proposed framework to reduce the imbalance between easy and hard samples. The experimental results based on the VEDIA, USCAS-AOD, and DOTA datasets show that the proposed framework outperforms other state-of-the-art vehicle detection algorithms for aerial images.
The Impact of Hurricane Irma on the Metabolism of St. Martin’s Island
Authors: Popescu Roxana , Beraud Hélène , Barroca Bruno
Published: August 2020

Due to their sometimes devastating and, at the same time, transformative effects, the impacts of major hurricanes on small islands leave their mark both on the way territories operate and on their future development. This was the case during the passage of hurricane Irma over the island of Saint Martin in 2017. By analyzing the stocks and circulation of hurricane waste flows, our aim was to see whether the inherent evolution of Saint Martin’s metabolism as a result of the island’s total destruction tended toward a lasting transformation of its waste management system and, therefore, toward the territory’s sustainability. This evolution was analyzed in a diachronic approach and over a short time frame. It was based on three structuring territorial metabolism dimensions: the intensity of waste flows, the spatial structure of the metabolism and the actors and techniques that explain it. Results show that while the intensity of the waste flows changed durably after Irma, the lasting transformation of the spatial structure and the actor system was less obvious and depended on the waste stream. Results also reveal the importance of reflecting on the development of recycling and reuse methods as a solution for improving post-hurricane waste planning on islands.
Investigating the Effects of IT Capability on Hotel Performance Based on DEA Approach: An Empirical Example of International Hotels in Hong Kong
Authors: Yin Pengzhen , Yang Min , Yang Ranran
Published: August 2020

IT capability improves organization resilience in uncertain social environments (such as the outbreak of COVID-19) and, thus, becomes a key factor in the organization of sustainable development. However, studies have rarely quantitatively examined the efficiency of IT capability and its effects on hotel performance. This study aims to investigate how and to what extent IT capability facilitates hotel operations. Context-dependent and measure-specific data envelopment analysis (DEA) models were employed to assess hotel performance and IT capability. The data from international hotels in Hong Kong were collected for an empirical analysis. The results indicated that the hotels in Hong Kong are classified as market leaders, challenges, followers, and nichers based on the efficiency scores. This study then analyzed the differences and relationship between hotel IT capability and hotel performance. The improvement targets of each input and output variable were also provided for further decision-making. Both theoretical and practical implications for hotel management are discussed.
Managers’ Informedness of Energy Issues in Tourism
Authors: Smolčić Jurdana Dora , Šverko Grdić Zvonimira , Krstinić Nižić Marinela
Published: August 2020

Energy and environmental issues are nowadays becoming more prominent, and business subjects in tourism should dedicate more effort to energy management. This can lead to a reduction in energy-related expenses, and it shows social responsibility and concern for the environment. In order to determine the informedness of managers in tourism concerning energy issues, empirical research was conducted in all seven counties of Adriatic Croatia. The questionnaire was filled out by 254 managers in tourism in such a way that the research covered business management (hotel, villa, camp, and apartment managers), managers in tourist boards, managers in units of local self-government, and managers among other stakeholders directly or indirectly involved in tourism. The questionnaire consisted of closed-ended questions answered using the Likert scale with 1 being the worst and 5 the best. The questionnaire’s reliability was tested using factor analysis and internal consistency analysis. The results showed that managers still have insufficient knowledge concerning the impact of energy and its link to tourism. Additionally, 66.4% of the participants considered their knowledge regarding energy issues in tourism to be poor or negligible. It can be concluded that continued education for managers is required as higher awareness leads to “greener” attitudes among managers in tourism.