bluuebunny/crossref_metadata_2025 huggingface dataset:
Fall Detection System-Based Posture-Recognition for Indoor Environments
Authors: Iazzi Abderrazak , Rziza Mohammed , Oulad Haj Thami Rachid
Published: February 2021

The majority of the senior population lives alone at home. Falls can cause serious injuries, such as fractures or head injuries. These injuries can be an obstacle for a person to move around and normally practice his daily activities. Some of these injuries can lead to a risk of death if not handled urgently. In this paper, we propose a fall detection system for elderly people based on their postures. The postures are recognized from the human silhouette which is an advantage to preserve the privacy of the elderly. The effectiveness of our approach is demonstrated on two well-known datasets for human posture classification and three public datasets for fall detection, using a Support-Vector Machine (SVM) classifier. The experimental results show that our method can not only achieves a high fall detection rate but also a low false detection.
Performance Assessment of a Planing Hull Using the Smoothed Particle Hydrodynamics Method
Authors: Tagliafierro Bonaventura , Mancini Simone , Ropero-Giralda Pablo , Domínguez José M. , Crespo Alejandro J. C. , Viccione Giacomo
Published: February 2021

Computational Fluid Dynamics simulations of planing hulls are generally considered less reliable than simulations of displacement hulls. This is due to the flow complexity around planing hulls, especially in the bow region, where the sprays are formed. The recent and constant increasing of computational capabilities allows simulating planing hull features, with more accurate turbulence models and advanced meshing procedures. However, mesh-based approaches based on the finite volume methods have shown to be limited in capturing all the phenomena around a planing hull. As such, the focus of this study is on evaluating the ability of the Smoothed Particle Hydrodynamics mesh-less method to numerically solve the 3-D flow around a planing hull and simulate more accurately the spray structures, which is a rather challenging task to be performed with mesh-based tools. A novel application of the DualSPHysics code for simulating a planing hull resistance test has been proposed and applied to the parent hull of the Naples warped planing hull Systematic Series. The drag and the running attitudes (heave and dynamic trim angle) are computed for a wide range of Froude’s numbers and discussed concerning experimental values.
A Novel Sea Surface Roughness Parameterization Based on Wave State and Sea Foam
Authors: Sun Difu , Song Junqiang , Li Xiaoyong , Ren Kaijun , Leng Hongze
Published: February 2021

A wave state related sea surface roughness parameterization scheme that takes into account the impact of sea foam is proposed in this study. Using eight observational datasets, the performances of two most widely used wave state related parameterizations are examined under various wave conditions. Based on the different performances of two wave state related parameterizations under different wave state, and by introducing the effect of sea foam, a new sea surface roughness parameterization suitable for low to extreme wind conditions is proposed. The behaviors of drag coefficient predicted by the proposed parameterization match the field and laboratory measurements well. It is shown that the drag coefficient increases with the increasing wind speed under low and moderate wind speed conditions, and then decreases with increasing wind speed, due to the effect of sea foam under high wind speed conditions. The maximum values of the drag coefficient are reached when the 10 m wind speeds are in the range of 30–35 m/s.
An Integrated Dynamic Model and Optimized Fuzzy Controller for Path Tracking of Deep-Sea Mining Vehicle
Authors: Dai Yu , Xue Cong , Su Qiao
Published: February 2021

The capability of path tracking largely determines the operational efficiency of deep-sea mining vehicles. In this paper, the relationships of vehicle–sediment mechanical interaction were obtained by sinkage and shear tests. Then, an overset grid method was used to establish the computational fluid dynamics (CFD) model of the vehicle, and the spatial hydrodynamic distribution was calculated in different motion states. Based on the above research, a multi-body dynamic (MBD) model of the mining vehicle was developed, which considered the spatial hydrodynamic effects and the mechanical interaction between vehicle and sediment. In addition, a path-tracking controller based on fuzzy logic control was proposed. A genetic algorithm optimized the fuzzy rules through co-simulation between the controller and the MBD model. Finally, the co-simulation results of the vehicle which moved along the expected path indicated that the performance of the optimized fuzzy controller was preferable to the original fuzzy controller.
3D Simulation with Flow-Induced Rotation for Non-Deformable Tidal Turbines
Authors: Robin Ilan , Bennis Anne-Claire , Dauvin Jean-Claude
Published: February 2021

The overall potential for recoverable tidal energy depends partly on the tidal turbine technologies used. One of problematic points is the minimum flow velocity required to set the rotor into motion. The novelty of the paper is the setup of an innovative method to model the fluid–structure interactions on tidal turbines. The first part of this work aimed at validating the numerical model for classical cases of rotation (forced rotation), in particular, with the help of a mesh convergence study. Once the model was independent from the mesh, the numerical results were tested against experimental data for both vertical and horizontal tidal turbines. The results show that a good correspondence for power and drag coefficients was observed. In the wake, the vortexes were well captured. Then, the fluid drive code was implemented. The results correspond to the expected physical behavior. Both turbines rotated in the correct direction with a coherent acceleration. This study shows the fundamental operating differences between a horizontal and a vertical axis tidal turbine. The lack of experiments with the free rotation speed of the tidal turbines is a limitation, and a digital brake could be implemented to overcome this difficulty.
Ibrexafungerp: A First-in-Class Oral Triterpenoid Glucan Synthase Inhibitor
Authors: Jallow Sabelle , Govender Nelesh P.
Published: February 2021

Ibrexafungerp (formerly SCY-078 or MK-3118) is a first-in-class triterpenoid antifungal or “fungerp” that inhibits biosynthesis of β-(1,3)-D-glucan in the fungal cell wall, a mechanism of action similar to that of echinocandins. Distinguishing characteristics of ibrexafungerp include oral bioavailability, a favourable safety profile, few drug–drug interactions, good tissue penetration, increased activity at low pH and activity against multi-drug resistant isolates including C. auris and C. glabrata. In vitro data has demonstrated broad and potent activity against Candida and Aspergillus species. Importantly, ibrexafungerp also has potent activity against azole-resistant isolates, including biofilm-forming Candida spp., and echinocandin-resistant isolates. It also has activity against the asci form of Pneumocystis spp., and other pathogenic fungi including some non-Candida yeasts and non-Aspergillus moulds. In vivo data have shown IBX to be effective for treatment of candidiasis and aspergillosis. Ibrexafungerp is effective for the treatment of acute vulvovaginal candidiasis in completed phase 3 clinical trials.
Disseminated Mucormycosis in Immunocompromised Children: Are New Antifungal Agents Making a Difference? A Multicenter Retrospective Study
Authors: Elitzur Sarah , Fischer Salvador , Arad-Cohen Nira , Barg Assaf , Ben-Harosh Miriam , Danino Dana , Elhasid Ronit , Gefen Aharon , Gilad Gil , Levy Itzhak , Shachor-Meyouhas Yael , Weinreb Sigal , Izraeli Shai , Barzilai-Birenboim Shlomit
Published: February 2021

Background: Mucormycosis is a life-threatening infection with a tendency for angioinvasion that may lead to progressive dissemination. Disseminated mucormycosis, defined as the involvement of two or more non-contiguous sites, is rare in children, and data concerning its management and outcome are scarce. The aim of this study was to assess the contemporary management strategies and outcomes of disseminated mucormycosis in the pediatric population. Methods: We conducted a retrospective search in six large tertiary medical centers for all cases of disseminated mucormycosis that occurred between 2009–2020 in patients aged 1–20 years. Results: Twelve cases were identified. Underlying conditions included hematological malignancies (n = 10), solid tumor (post-autologous hematopoietic stem cell transplantations; n = 1), and solid organ (liver) transplantation (n = 1). In all cases, amphotericin B formulations were administered as first-line therapy; in eight cases, they were also administered in combination with an echinocandin or triazole. Seven patients underwent surgical debridement procedures. The six-week mortality was 58%. Among the patients diagnosed between 2009–2015, one of the six survived, and of those diagnosed between 2016–2020, four of the six were salvaged. Conclusions: Disseminated mucormycosis is a life-threatening and often fatal disease, and improved diagnostic and therapeutic strategies are needed. Nevertheless, in this population-based study, five patients (42%) were salvaged through combined liposomal amphotericin/triazole treatment and extensive surgical interventions.
Screening Methods for Isolation of Biocontrol Epiphytic Yeasts against Penicillium digitatum in Lemons
Authors: Pereyra Martina María , Díaz Mariana Andrea , Soliz-Santander Fabricio Fabián , Poehlein Anja , Meinhardt Friedhelm , Daniel Rolf , Dib Julián Rafael
Published: February 2021

Worldwide, the green rot caused by Penicillium digitatum is one of the most aggressive postharvest diseases of lemons. Searching for sustainable alternatives to chemical fungicides, epiphytic yeasts as potential biocontrol agents were isolated from citrus fruits using a tailor-made selective medium. For disclosing their antagonistic potential against P. digitatum, obtained isolates were subjected to direct screening methods, both in vitro and in vivo. In the course of the primary in vitro screening that comprised dual culture assays, 43 yeast strains displaying antagonistic activities against the pathogen were selected. Subsequently, such strains were subjected to an in vivo screening that consisted of a microscale test, allowing the selection of six yeast strains for further analysis. In the final screening using macroscale in vivo tests, three strains (AcL2, AgL21, and AgL2) displaying the highest efficiencies to control P. digitatum were identified. The protection efficiencies in lemons were 80 (AcL2), 76.7 (AgL21), and 75% (AgL2). Based on sequence analysis of the PCR amplified D1/D2 domains of the 26S rRNA genes, they were identified as representatives of the species Clavispora lusitaniae. Interestingly, the strains exhibited a broad action spectrum among citrus fruits as they were also able to combat the green mold disease in grapefruit and two orange varieties. The direct screening methods applied in this study favored the recovery of efficient candidates for application as biological control agents to combat fungal infestations of citrus fruits.
Application of Bio-Friendly Formulations of Chitinase-Producing Streptomyces cellulosae Actino 48 for Controlling Peanut Soil-Borne Diseases Caused by Sclerotium rolfsii
Authors: Abo-Zaid Gaber , Abdelkhalek Ahmed , Matar Saleh , Darwish Mai , Abdel-Gayed Muhammad
Published: February 2021

Of ten actinobacterial isolates, Streptomyces cellulosae Actino 48 exhibited the strongest suppression of Sclerotium rolfsii mycelium growth and the highest chitinase enzyme production (49.2 U L−1 min−1). The interaction between Actino 48 and S. rolfsii was studied by scanning electron microscope (SEM), which revealed many abnormalities, malformations, and injuries of the hypha, with large loss of S. rolfsii mycelia density and mass. Three talc-based formulations with culture broth, cell-free supernatant, and cell pellet suspension of chitinase-producing Actino 48 were characterized using SEM, Fourier transform infrared spectroscopy (FTIR), and a particle size analyzer. All formulations were evaluated as biocontrol agents for reducing damping-off, root rot, and pods rot diseases of peanut caused by S. rolfsii under greenhouse and open-field conditions. The talc-based culture broth formulation was the most effective soil treatment, which decreased the percentage of peanut diseases under greenhouse and open-field conditions during two successive seasons. The culture broth formulation showed the highest increase in the dry weight of peanut shoots, root systems, and yielded pods. The transcriptional levels of three defense-related genes (PR-1, PR-3, and POD) were elevated in the culture broth formulation treatment compared with other formulations. Subsequently, the bio-friendly talc-based culture broth formulation of chitinase-producing Actino 48 could potentially be used as a biocontrol agent for controlling peanut soil-borne diseases caused by S. rolfsii.
Central Nervous System Mold Infections in Children with Hematological Malignancies: Advances in Diagnosis and Treatment
Authors: Luckowitsch Marie , Rudolph Henriette , Bochennek Konrad , Porto Luciana , Lehrnbecher Thomas
Published: February 2021

The incidence of invasive mold disease (IMD) has significantly increased over the last decades, and IMD of the central nervous system (CNS) is a particularly severe form of this infection. Solid data on the incidence of CNS IMD in the pediatric setting are lacking, in which Aspergillus spp. is the most prevalent pathogen, followed by mucorales. CNS IMD is difficult to diagnose, and although imaging tools such as magnetic resonance imaging have considerably improved, these techniques are still unspecific. As microscopy and culture have a low sensitivity, non-culture-based assays such as the detection of fungal antigens (e.g., galactomannan or beta-D-glucan) or the detection of fungal nucleic acids by molecular assays need to be validated in children with suspected CNS IMD. New and potent antifungal compounds helped to improve outcome of CNS IMD, but not all agents are approved for children and a pediatric dosage has not been established. Therefore, studies have to rapidly evaluate dosage, safety and efficacy of antifungal compounds in the pediatric setting. This review will summarize the current knowledge on diagnostic tools and on the management of CNS IMD with a focus on pediatric patients.
A New Duplex PCR-Assay for the Detection and Identification of Paracoccidioides Species
Authors: Pinheiro Breno Gonçalves , Pôssa Ana Paula , Della Terra Paula Portella , de Carvalho Jamile Ambrósio , Ricci Giannina , Nishikaku Angela Satie , Hahn Rosane Christine , Camargo Zoilo Pires de , Rodrigues Anderson Messias
Published: February 2021

Paracoccidioidomycosis (PCM) is a life-threatening systemic fungal infection caused by members of the Paracoccidioides brasiliensis complex and P. lutzii. Routine diagnoses of PCM down to the species level using classical mycological approaches are unspecific due to overlapping phenotypes. There is an urgent need for specific, sensitive, and cost-effective molecular tools to diagnose PCM. Variation among the exon-2 of the gp43 gene was exploited to design species-specific primer pairs to discriminate between members of the P. brasiliensis complex and P. lutzii in a duplex PCR assay. Primer-BLAST searches revealed highly species-specific primers, and no significant region of homology was found against DNA databases except for Paracoccidioides species. Primers PbraCx-F and PbraCx-R targeting P. brasiliensis DNA produced an amplicon of 308 bp, while primers Plu-F and Plu-R targeting P. lutzii DNA generated an amplicon of 142 bp. The lower limit of detection for our duplex PCR assay was 1 pg of gDNA. A panel of 62 Paracoccidioides revealed 100% specificity (AUC = 1.000, 95%CI 0.972–1.000, p < 0.0001) without cross-reacting with other medically relevant fungi or human DNA. As a proof of concept, we demonstrated the accurate identification of the P. brasiliensis complex (n = 7) or P. lutzii (n = 6) from a broad range of formalin-fixed, paraffin-embedded (FFPE) tissues of PCM patient’s organs. In four cases, FFPE PCR results confirmed, for the first time, co-infection due to P. brasiliensis (S1) and P. lutzii in the same biopsy. Our duplex PCR assay is useful to detect and differentiate members of the P. brasiliensis complex and P. lutzii, providing clinical laboratories with an important tool to be applied routinely, especially in atypical cases such as those featuring negative serology and positive mycological examination of clinical specimens as well as for the investigation of putative co-infection cases. This will likely benefit thousands of infected patients every year in a wide area of the Americas.
Re-Evaluation of the Podosphaera tridactyla Species Complex in Australia
Authors: Smith Reannon L. , May Tom W. , Kaur Jatinder , Sawbridge Tim I. , Mann Ross C. , Pascoe Ian G. , Edwards Jacqueline
Published: February 2021

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malusprunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po.pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.
The Potential of Mesenchymal Stromal Cells in Neuroblastoma Therapy for Delivery of Anti-Cancer Agents and Hematopoietic Recovery
Authors: Hochheuser Caroline , Kunze Nina Y. , Tytgat Godelieve A. M. , Voermans Carlijn , Timmerman Ilse
Published: February 2021

Neuroblastoma is one of the most common pediatric cancers and a major cause of cancer-related death in infancy. Conventional therapies including high-dose chemotherapy, stem cell transplantation, and immunotherapy approach a limit in the treatment of high-risk neuroblastoma and prevention of relapse. In the last two decades, research unraveled a potential use of mesenchymal stromal cells in tumor therapy, as tumor-selective delivery vehicles for therapeutic compounds and oncolytic viruses and by means of supporting hematopoietic stem cell transplantation. Based on pre-clinical and clinical advances in neuroblastoma and other malignancies, we assess both the strong potential and the associated risks of using mesenchymal stromal cells in the therapy for neuroblastoma. Furthermore, we examine feasibility and safety aspects and discuss future directions for harnessing the advantageous properties of mesenchymal stromal cells for the advancement of therapy success.
Engineering Procurement Construction in the Context of Belt and Road Infrastructure Projects in West Asia: A SWOT Analysis
Authors: Nikjow Mohammad Ajmal , Liang Li , Qi Xijing , Sepasgozar Samad
Published: February 2021

Engineering procurement and construction (EPC) is a normative practice globally approved since China has been engaging in international cooperation under the Belt and Road Initiative (BRI) infrastructure development. EPC has been adopted in the delivery of BRI infrastructure projects in other countries. Compared to the domestic method of contract, EPC remains at a low level in management practice, such as a lack of coordinating diverse project stakeholders, high cost of information communication, and risk in complex environments in West Asia (WA). However, no research has conducted a strategic analysis of the current situation of EPC for BRI infrastructure projects in West Asian countries. This study aims to understand the current status quo of EPC for BRI projects in WA by performing a strength, weakness, opportunity, and threats (SWOT) analysis and with the support of data collected from the literature review and semi-structured interviews with EPC stakeholders. The study brings awareness along which internally and externally circumstances of the EPC for BRI infrastructure projects can be perceived by major stakeholders participating. The four critical strategies presented based on the SWOTs identified could help EPC firms develop and promote EPC to implement BRI infrastructure projects in WA at the strategic level.
Environmental Kuznets Curve Hypothesis on CO2 Emissions: Evidence for China
Authors: Zhang Jihuan
Published: February 2021

China is the largest CO2 emitter in the world, and it shared 28% of the global CO2 emissions in 2017. According to the Paris Agreement, it is estimated that China’s CO2 emissions will reach its peak by 2030. However, whether or not the CO2 emissions in China will rise again from its peak is still unknown. If the emission level continues to increase, the Chinese policymakers might have to introduce a severe CO2 reduction policy. The aim of this paper is to conduct an empirical analysis on the long-standing relationship between CO2 emissions and income while controlling energy consumption, trade openness, and urbanization. The autoregressive distributed lag (ARDL) model and the bounds test were adopted in evaluating the validity of the Environmental Kuznets Curve (EKC) hypothesis. The quantile regression was also used as an inference approach. The study reveals two major findings: first, instead of the conventional U-shaped EKC hypothesis, there is the N-shaped relationship between CO2 emissions and real gross domestic product (GDP) per capita in the long run. Second, a positive effect of energy consumption and a negative effect of urbanization on CO2 emissions, in the long run, are also estimated. Quantitatively, if energy consumption rises by 1%, then CO2 emissions will increase by 0.9% in the long run. Therefore, the findings suggest that a breakthrough, in terms of policymaking and energy innovation under China’s specific socioeconomic and political circumstances, are required for future decades.
Conservation Debates: People’s Perceptions and Values towards a Privately Protected Area in Southern Ecuador
Authors: Iñiguez-Gallardo Verónica , Reyes-Bueno Fabián , Peñaranda Olga
Published: February 2021

The perceptions and values that local communities have towards protected areas are of great value for the improvement of these territories’ management. Such perceptions and values are often absent in the conservation planning process, particularly in those privately protected areas that are established in areas where the land tenure system is based not only on ownership but also on customary uses. Drawing on qualitative and quantitative data obtained through semi-structured interviews with key stakeholders and members of communities surrounding a privately protected area in southern Ecuador, we identify that the level of collaboration with the managers, the distance to the protected area, the percentage of untitled land, and the dependence on the resources (customary uses) are among the variables affecting these perceptions and values. Positive perceptions towards protected areas and naturalistic values are developed among those who collaborate with the protected area managers, whereas negative perceptions, and a mix of naturalistic and biospheric values are developed among those who have a sense of a lack of attention to social needs although supporting nature conservation at the same time. The evidence presented shows the importance of matching local peoples’ expectations with conservation goals during the establishment of a protected area.
Establishment of Land Use Suitability Mapping Criteria Using Analytic Hierarchy Process (AHP) with Practitioners and Beneficiaries
Authors: Morales Florentino , de Vries Walter
Published: February 2021

The presence of land use conflicts is often unavoidable as land is finite and a scarce resource. With development as a prime goal, the increasing demands for specific uses make the situation more serious than it was before. In the context of land uses, suitability determines the inherent capacity of the land to perform a defined use with optimum efficiency and sustainability. However, single land use suitability analysis could not answer the overall objective of land allocation. Thus, this study considers the primary and general land uses with the valuable evaluation criteria necessary for simultaneous land use suitability analyses. This paper aims at establishing the relevant and necessary evaluation criteria for Multicriteria Evaluation (MCE) using the Analytic Hierarchy Process (AHP) for land use suitability analysis for residential, industrial, commercial, agricultural, and forest land uses. The factors which could be used as indicators in land suitability analysis were derived from both literature review and through experts’ knowledge. Correspondingly, the relative importance (weights) of the criteria established were derived using pairwise comparisons through the AHP technique readily available for subsequent GIS analysis. Last, the criteria developed are general in nature and could be replicated and/or altered depending upon the local needs and situations.
Can Frequency Account for the Grammatical Choices of Children and Adults in Nominal Modification Contexts? Evidence from Elicited Production and Child-Directed Speech
Authors: Sanfelici Emanuela , Schulz Petra
Published: February 2021

There is consensus that languages possess several grammatical variants satisfying the same conversational function. Nevertheless, it is a matter of debate which principles guide the adult speaker’s choice and the child’s acquisition order of these variants. Various proposals have suggested that frequency shapes adult language use and language acquisition. Taking the domain of nominal modification as its testing ground, this paper explores in two studies the role that frequency of structures plays for adults’ and children’s structural choices in German. In Study 1, 133 three- to six-year-old children and 21 adults were tested with an elicited production task prompting participants to identify an agent or a patient referent among a set of alternatives. Study 2 analyzed a corpus of child-directed speech to examine the frequency of passive relative clauses, which children, similar to adults, produced very often in Study 1. Importantly, passive relatives were found to be infrequent in the child input. These two results show that the high production rate of rare structures, such as passive relatives, is difficult to account for with frequency. We claim that the relation between frequency in natural speech and use of a given variant in a specific context is indirect: speakers may opt for the less grammatically complex computation rather than for the variant most frequently used in spontaneous speech.
Chronological Incongruences between Mitochondrial and Nuclear Phylogenies of Aedes Mosquitoes
Authors: Zadra Nicola , Rizzoli Annapaola , Rota-Stabelli Omar
Published: February 2021

One-third of all mosquitoes belong to the Aedini, a tribe comprising common vectors of viral zoonoses such as Aedes aegypti and Aedes albopictus. To improve our understanding of their evolution, we present an updated multigene estimate of Aedini phylogeny and divergence, focusing on the disentanglement between nuclear and mitochondrial phylogenetic signals. We first show that there are some phylogenetic discrepancies between nuclear and mitochondrial markers which may be caused by wrong taxa assignment in samples collections or by some stochastic effect due to small gene samples. We indeed show that the concatenated dataset is model and framework dependent, indicating a general paucity of signal. Our Bayesian calibrated divergence estimates point toward a mosquito radiation in the mid-Jurassic and an Aedes radiation from the mid-Cretaceous on. We observe, however a strong chronological incongruence between mitochondrial and nuclear data, the latter providing divergence times within the Aedini significantly younger than the former. We show that this incongruence is consistent over different datasets and taxon sampling and that may be explained by either peculiar evolutionary event such as different levels of saturation in certain lineages or a past history of hybridization throughout the genus. Overall, our updated picture of Aedini phylogeny, reveal a strong nuclear-mitochondrial incongruence which may be of help in setting the research agenda for future phylogenomic studies of Aedini mosquitoes.
Ethyl 1-Butyl-2-(2-hydroxy-4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate
Authors: Sathyanarayana Reshma , Poojary Boja
Published: February 2021

Ethyl 4-(butylamino)-3-nitrobenzoate upon “one-pot” nitro-reductive cyclization using sodium dithionite and substituted aldehyde in dimethyl sulphoxide affords ethyl 1-butyl-2-(2-hydroxy-4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate in an 87% yield. The structural characterization was determined by Fourier-transfer infrared spectroscopy (FT-IR), Proton nuclear magnetic resonance (1H-NMR), Carbon-13 nuclear magnetic resonance (13C-NMR), mass spectrometry, Ultraviolet-visible(UV-Vis), photoluminescence (PL), thin-film solid emission spectra, cyclic voltammetry (CV) and thermogravimetric (TGA) analysis. Molecular electrostatic potential (MEP) was studied to determine the reactive sites of the molecule.
Laser Shock Peening of SiCp/2009Al Composites: Microstructural Evolution, Residual Stress and Fatigue Behavior
Authors: Sun Rujian , Cao Ziwen , Zhang Yongxin , Zhang Hepeng , Yu Yingwei , Che Zhigang , Wu Junfeng , Zou Shikun , Guo Wei
Published: February 2021

SiC particle reinforced aluminum alloy has a wide application in the aerospace industries. In this study, laser shock peening (LSP), an advanced surface modification technique, was employed for SiCp/2009Al composite to reveal its microstructure, microhardness and residual stress evolution. After peening, high densities of dislocations were induced in the aluminum substrate, and stacking faults were introduced into the SiC particle. The microhardness was increased from 155–170 HV to 170–185 HV, with an affected depth of more than 1.5 mm. Compressive residual stresses of more than 200 MPa were introduced. The three-point bending fatigue of the base material, laser peened and milled after laser peened specimens with artificial crack notch fabricated by a femtosecond laser was investigated. The average fatigue lives of laser peened and milled after laser peened specimens were increased by up to 10.60 and 2.66 times, compared with the base material. This combined fundamental and application-based research seeks to comprehensively explore the applicability of LSP on metal matrix composite.
Vehiculation of Methyl Salicylate from Microcapsules Supported on Textile Matrix
Authors: Mendes Samira , Catarino André , Zille Andréa , Fernandes Nádia , Bezerra Fabricio Maestá
Published: February 2021

In recent years, textile industries have focused their attention on the development of functional finishing that presents durability and, consequently, controlled release. However, in the case of methyl salicylate microcapsules supported on a textile matrix, studies indicate only the interactions between substrate and microcapsules and the drug delivery system, not applying the release equations. This study reports the mechanism and kinetics of controlled release of microcapsules of gelatin and gum Arabic containing methyl salicylate as active ingredient incorporated into textile matrices. According to the results presented, it was possible to verify that the wall materials participated in the coacervation process, resulting in microcapsules with well-defined geometry, besides promoting the increase of the thermal stability of the active principle. The samples (100% cotton, CO, and 100% polyamide, PA) functionalized with microcapsules released methyl salicylate in a controlled manner, based on the adjustment made by the Korsmeyer–Peppas model, indicating a Fickian mechanism. The influence of temperature was noticeable when the samples were subjected to washing, since with higher temperature (50 °C), the release was more pronounced than when subjected to lower temperature (37 °C). The results presented in this study indicate that the mechanism of backbone release is influenced by the textile matrix and by the durability of the microcapsule during the wash cycles.
Influence of Sintering Process Conditions on Microstructural and Mechanical Properties of Boron Carbide Ceramics Synthesized by Spark Plasma Sintering
Authors: Liu Yingying , Ge Sheng , Huang Yihua , Huang Zhengren , Zhang Deku
Published: February 2021

Boron carbide (B4C) ceramics were synthesized by spark plasma sintering at a temperature between 1600 and 2050 °C without employing any sintering additives. The effect of sintering process parameters, such as temperature, holding time, pressure, hearting rate, and pulsed electric current, and the particle size of the raw powder on the densification behavior and mechanical properties of B4C ceramics, were comprehensively and systematically investigated. Hardness and fracture toughness of B4C that has a density close to the theoretical value were found to be 33.5 ± 0.2 GPa and 3.21 ± 0.13 MPa·m1/2, respectively. Electron backscatter diffraction (EBSD) analysis revealed no abnormal growth of grains due to an increase in holding time and pressure. Twin structures present in ceramics are beneficial for their mechanical performance.
Structural and Magnetic Properties of Ni/C Composites Synthesized from Beet Pulp and Corn Stems
Authors: Bordun Ihor , Pidluzhna Anna , Ivashchyshyn Fedir , Borysiuk Anatoliy , Całus Dariusz , Chwastek Krzysztof
Published: February 2021

Nickel/carbon composites were synthesized by the carbonization method with the use of the steam-gas activation technique. Beet pulp and corn stems were used as initial raw materials for composites synthesis. The obtained substances were analyzed by means of scanning electron microscopy, X-ray diffraction analysis, and magnetic properties investigation. The presence of nickel in synthesized composites was estimated during analysis, and the average particle size of nickel was determined as well. The specific surface area of the obtained samples was measured by the technique of Methylene blue sorption from the aqueous solution. The results of the performed investigation demonstrate clearly the promising application of synthesized composites as magneto-active sorbents, which could be easily separated from water solutions.
Performance Analysis on the Use of Oscillating Water Column in Barge-Based Floating Offshore Wind Turbines
Authors: Aboutalebi Payam , M’zoughi Fares , Garrido Izaskun , Garrido Aitor J.
Published: February 2021

Undesired motions in Floating Offshore Wind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform motions. The newly proposed barge structure aims to reduce the tower displacements and platform’s oscillations, particularly in rotational movements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to oppose the oscillatory motion of the waves. Response Amplitude Operator (RAO) is used to predict the motions of the system exposed to different wave frequencies. From the RAOs analysis, the system’s performance has been evaluated for representative regular wave periods. Simulations using numerical tools show the positive impact of the added OWCs on the system’s stability. The results prove that the proposed platform presents better performance by decreasing the oscillations for the given range of wave frequencies, compared to the traditional barge platform.
Study on the Intelligent Modeling of the Blade Aerodynamic Force in Compressors Based on Machine Learning
Authors: Zhang Mingming , Hao Shurong , Hou Anping
Published: February 2021

In order to obtain the aerodynamic loads of the vibrating blades efficiently, the eXterme Gradient Boosting (XGBoost) algorithm in machine learning was adopted to establish a three-dimensional unsteady aerodynamic force reduction model. First, the database for the unsteady aerodynamic response during the blade vibration was acquired through the numerical simulation of flow field. Then the obtained data set was trained by the XGBoost algorithm to set up the intelligent model of unsteady aerodynamic force for the three-dimensional blade. Afterwards, the aerodynamic load could be gained at any spatial location during blade vibration. To evaluate and verify the reliability of the intelligent model for the blade aerodynamic load, the prediction results of the machine learning model were compared with the results of Computation Fluid Dynamics (CFD). The determination coefficient R2 and the Root Mean Square Error (RMSE) were introduced as the model evaluation indicators. The results show that the prediction results based on the machine learning model are in good agreement with the CFD results, and the calculation efficiency is significantly improved. The results also indicate that the aerodynamic intelligent model based on the machine learning method is worthy of further study in evaluating the blade vibration stability.
The Dubovitskii and Milyutin Methodology Applied to an Optimal Control Problem Originating in an Ecological System
Authors: Coronel Aníbal , Huancas Fernando , Lozada Esperanza , Rojas-Medar Marko
Published: February 2021

We research a control problem for an ecological model given by a reaction–diffusion system. The ecological model is given by a nonlinear parabolic PDE system of three equations modelling the interaction of three species by considering the standard Lotka-Volterra assumptions. The optimal control problem consists of the determination of a coefficient such that the population density of predator decreases. We reformulate the control problem as an optimal control problem by introducing an appropriate cost function. Then, we introduce and prove three types of results. A first contribution of the paper is the well-posedness framework of the mathematical model by considering that the interaction of the species is given by a general functional responses. Second, we study the differentiability properties of a cost function. The third result is the existence of optimal solutions, the existence of an adjoint state, and a characterization of the control function. The first result is proved by the application of semigroup theory and the second and third result are proved by the application of Dubovitskii and Milyutin formalism.
Properties of the Global Total k-Domination Number
Authors: Hernández Mira Frank A. , Parra Inza Ernesto , Sigarreta Almira José M. , Vakhania Nodari
Published: February 2021

A nonempty subset D⊂V of vertices of a graph G=(V,E) is a dominating set if every vertex of this graph is adjacent to at least one vertex from this set except the vertices which belong to this set itself. D⊆V is a total k-dominating set if there are at least k vertices in set D adjacent to every vertex v∈V, and it is a global total k-dominating set if D is a total k-dominating set of both G and G¯. The global total k-domination number of G, denoted by γktg(G), is the minimum cardinality of a global total k-dominating set of G, GTkD-set. Here we derive upper and lower bounds of γktg(G), and develop a method that generates a GTkD-set from a GT(k−1)D-set for the successively increasing values of k. Based on this method, we establish a relationship between γ(k−1)tg(G) and γktg(G), which, in turn, provides another upper bound on γktg(G).
A Framework for Analysis and Prediction of Operational Risk Stress
Authors: Mitic Peter
Published: February 2021

A model for financial stress testing and stability analysis is presented. Given operational risk loss data within a time window, short-term projections are made using Loess fits to sequences of lognormal parameters. The projections can be scaled by a sequence of risk factors, derived from economic data in response to international regulatory requirements. Historic and projected loss data are combined using a lengthy nonlinear algorithm to calculate a capital reserve for the upcoming year. The model is embedded in a general framework, in which arrays of risk factors can be swapped in and out to assess their effect on the projected losses. Risk factor scaling is varied to assess the resilience and stability of financial institutions to economic shock. Symbolic analysis of projected losses shows that they are well-conditioned with respect to risk factors. Specific reference is made to the effect of the 2020 COVID-19 pandemic. For a 1-year projection, the framework indicates a requirement for an increase in regulatory capital of approximately 3% for mild stress, 8% for moderate stress, and 32% for extreme stress. The proposed framework is significant because it is the first formal methodology to link financial risk with economic factors in an objective way without recourse to correlations.
Lyophilization Serves as an Effective Strategy for Drug Development of the α9α10 Nicotinic Acetylcholine Receptor Antagonist α-Conotoxin GeXIVA[1,2]
Authors: Li Zhiguo , Han Xiaolu , Hong Xiaoxuan , Li Xianfu , Gao Jing , Zhang Hui , Zheng Aiping
Published: February 2021

α-Conotoxin GeXIVA[1,2] is a highly potent and selective antagonist of the α9α10 nicotinic acetylcholine receptor (nAChR) subtype. It has the advantages of strong efficacy, no tolerance, and no effect on motor function, which has been expected help patients with neuropathic pain. However, drug development for clinical use is severely limited owing to its instability. Lyophilization is applied as the most preferred method to solve this problem. The prepared lyophilized powder is characterized by differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), and Fourier transform infrared spectroscopy (FTIR). Molecular simulation is also used to explore the internal distribution and forces formed in the system. The analgesic effect on paclitaxel-induced neuropathic pain following single and 14-day repeated administrations are evaluated by the von Frey test and the tail-flick test. Trehalose combined with mannitol in a ratio of 1:1 is employed as the excipients in the determined formulation, where trehalose acts as the stabilizer and mannitol acts as the bulking agent, according to the results of DSC, PXRD, and FTIR. Both GeXIVA[1,2] (API) and GeXIVA[1,2] lyophilized powder (formulation) could produce stable analgesic effect. These results indicated that GeXIVA[1,2] lyophilized powder could improve the stability and provide an effective strategy to push it into clinical use as a new analgesic drug.
The Seaweed Diet in Prevention and Treatment of the Neurodegenerative Diseases
Authors: Pereira Leonel , Valado Ana
Published: February 2021

Edible marine algae are rich in bioactive compounds and are, therefore, a source of bioavailable proteins, long chain polysaccharides that behave as low-calorie soluble fibers, metabolically necessary minerals, vitamins, polyunsaturated fatty acids, and antioxidants. Marine algae were used primarily as gelling agents and thickeners (phycocolloids) in food and pharmaceutical industries in the last century, but recent research has revealed their potential as a source of useful compounds for the pharmaceutical, medical, and cosmetic industries. The green, red, and brown algae have been shown to have useful therapeutic properties in the prevention and treatment of neurodegenerative diseases: Parkinson, Alzheimer’s, and Multiple Sclerosis, and other chronic diseases. In this review are listed and described the main components of a suitable diet for patients with these diseases. In addition, compounds derived from macroalgae and their neurophysiological activities are described.
Idazoxan and Efaroxan Potentiate the Endurance Performances and the Antioxidant Activity of Ephedrine in Rats
Authors: Rusu-Zota Gabriela , Burlui Alexandra , Rezus Elena , Paduraru Luminita , Sorodoc Victorita
Published: February 2021

Background and objectives: The connections between the imidazoline system and multiple other neurotransmitter systems in the brain (adrenergic, dopaminergic, serotoninergic, glutamatergic, opioid) indicate the complexity of the mechanisms underlying motor activity and behavior. The aim of the present research was to investigate the effects of the combination of ephedrine (EPD) and imidazoline antagonists idazoxan (IDZ) and efaroxan (EFR) on the endurance performance in the treadmill test in rats. Materials and Methods: We used Wistar rats distributed as follows: Group 1 (Control) receiving distilled water 0.3 mL/100 g body weight; Group 2 (EPD) receiving 20 mg/kg ephedrine; Group 3 (EPD + IDZ) receiving 20 mg/kg ephedrine + 3 mg/kg idazoxan; Group 4 (EPD + EFR) receiving 20 mg/kg ephedrine + 1 mg/kg efaroxan. An additional group (C) of animals receiving 0.3 mL/100 g body weight distilled water (but not subjected to effort) was used. Endurance capacity was evaluated using a treadmill running PanLAB assay. The evaluation of the substances’ influence on oxidative stress was performed by spectrophotometric determination of superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity. Results: Treatment with EPD-IDZ and EPD-EFR were correlated with a longer distance traveled on the belt and with a decrease in the necessary electric shocks to motivate the animal to continue running in the forced locomotion test. Additionally, an increase in the activity of antioxidant enzymes was found. Conclusions: Idazoxan and efaroxan potentiated the physical effort-related effects of ephedrine with regard to endurance capacity and antioxidant activity in rats.