bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge, Attitudes, and Practices Regarding COVID-19 Among Healthcare Workers in Venezuela: An Online Cross-Sectional Survey
Authors: Mendoza Millán Daniela Lucía , Carrión-Nessi Fhabián Stevens , Mejía Bernard Mario Daniel , Marcano-Rojas María Victoria , Omaña Ávila Óscar Daniel , Doval Fernández Juan Manuel , Chacón Labrador Fabián Rafael , Quintero Rodríguez Adriana , Gasparini Vega Sebastian , Tami Adriana , Maricuto Andrea L. , Velásquez Viledy L. , Landaeta María Eugenia , Figuera Manuel , Chavero Melynar , Figuera Luisamy , Camejo-Ávila Natasha A. , Forero-Peña David A.
Published: July 2021

Background: The deterioration of Venezuela's health system in recent years undoubtedly contributes to an increased impact of the COVID-19 pandemic. Understanding healthcare workers' (HCWs) knowledge, attitudes, and practices (KAPs) toward COVID-19 in the early stages of the pandemic could inform their medical training and improve their preparedness.

Methods: A online national cross-sectional survey was conducted between May 26th and May 30th, 2020, to assess KAPs among HCWs in Venezuela.

Results: A total of 1,441 HCWs from all 24 regions of the country responded to the survey. The mean age of the HCWs was 44 (SD [standard deviation] 14) years; most were women (66.4%). Most HCWs were specialized doctors (48%), followed by nurses (13%) and resident doctors (12.3%). The majority of HCWs had good knowledge (76.3%), obtained information mainly from scientific literature (85.4%); had negative attitudes (53.6%), felt uncomfortable with their work during the current pandemic (59.8%); and reported appropriate practices (76.9%). However, participation in COVID-19 related training was absent in more than half of the HCWs. Positive attitudes were significantly more frequent in frontline workers than in non-frontline workers (p = 0.001). Bioanalysts, students, and doctors were more likely to have good knowledge; participating in training was a predictor for positive attitudes and older age was an appropriate practice predictor.

Conclusions: HCWs, knowledge in Venezuela could be improved by strengthening education and training programs. Strategies should focus on reducing fear and improving attitudes toward the care of COVID-19 patients, as well as the promotion of preventive practices.
Diplomatic Collaborative Solutions to Assure the Adoption of the European Single Market Amid the COVID-19 Pandemic
Authors: Logar Silvia , Alessandro Rizzardo
Published: July 2021

As the COVID-19 crisis has shown, the lack of harmonized and coordinated actions superseding national borders represented a limit to the full implementation of already existing legal binding instruments at the European level. It is recognized that the existing levels of globalization have contributed to accelerate the large-scale transmission of viruses and increased the likelihood of a pandemic public health crisis. This article aims to highlight the importance of greater bilateral cooperation to mitigate the health and economic impact of the coronavirus disease 2019 (COVID-19) pandemic. It focuses on the implementation of diplomatic collaborative systems to assure the full implementation of the European single market as well as the adoption of standardized health information platforms as a part of pandemic preparedness and control measures.
Can Bees Help us Find New Antibiotics?
Authors: Goggin Kirstie A. , Baillie Les
Published: July 2021

Antibiotics are very important for treating bacterial infections in humans, pets, and livestock. However, improper use of antibiotics has resulted in antibiotic resistance, making it difficult to treat some infections. There is an urgent need to discover new antibiotics, but how do we find them? The answer potentially lies with bees and the honey they produce. Bees who feed on unique plants produce honey with high levels of antibiotic activity, due to the presence of antibacterial compounds in the nectar that the bees collect to make honey. In addition to nectar, the bees also collect pollen, which contains a sample of each visited plant’s unique DNA. By studying this DNA, we have identified plants that are sources of the antibacterial compounds found in honey. We are now working to develop new antibiotics from this honey, and we have installed beehives on university buildings to create our own super honey.
Increasing the Legume–Rhizobia Symbiotic Efficiency Due to the Synergy between Commercial Strains and Strains Isolated from Relict Symbiotic Systems
Authors: Safronova Vera , Sazanova Anna , Kuznetsova Irina , Belimov Andrey , Guro Polina , Karlov Denis , Yuzikhin Oleg , Chirak Elizaveta , Verkhozina Alla , Afonin Alexey , Andronov Evgeny , Tikhonovich Igor
Published: July 2021

The phenomenon of rhizobial synergy was investigated to increase the efficiency of nitrogen-fixing symbiosis of alfalfa (Medicago varia Martyn), common vetch (Vicia sativa L.) or red clover (Trifolium pratense L.). These plants were co-inoculated with the respective commercial strains Sinorhizobium meliloti RCAM1750, Rhizobium leguminosarum RCAM0626 or R. leguminosarum RCAM1365 and with the strains Mesorhizobium japonicum Opo-235, M. japonicum Opo-242, Bradyrhizobium sp. Opo-243 or M. kowhaii Ach-343 isolated from the relict legumes Oxytropis popoviana Peschkova and Astragalus chorinensis Bunge. The isolates mentioned above had additional symbiotic genes (fix, nif, nod, noe and nol) as well as the genes promoting plant growth and symbiosis formation (acdRS, genes associated with the biosynthesis of gibberellins and auxins, genes of T3SS, T4SS and T6SS secretion systems) compared to the commercial strains. Nodulation assays showed that in some variants of co-inoculation the symbiotic parameters of plants such as nodule number, plant biomass or acetylene reduction activity were increased. We assume that the study of microbial synergy using rhizobia of relict legumes will make it possible to carry out targeted selection of co-microsymbionts to increase the efficiency of agricultural legume–rhizobia systems.
Dysregulation of PI3K/Akt/PTEN Pathway in Canine Mammary Tumor
Authors: Kim Soo-Hyeon , Seung Byung-Joon , Cho Seung-Hee , Lim Ha-Young , Bae Min-Kyung , Sur Jung-Hyang
Published: July 2021

The PI3K/Akt/PTEN axis is one of the most important signaling pathways in tumorigenesis. Recently, mutation of PIK3CA has been highlighted due to the similarities of mutational hotspots in both dogs and humans. PIK3CA H1047R (c.3140A > G) has been discovered as the most common mutational hot spot in canine mammary tumor in recent studies, while the feature of PIK3CA-mutated canine mammary tumor is obscure. Methods: A total of 83 mammary samples classified as normal (n = 13), adenoma (n = 25), low-grade carcinoma (n = 21), and high-grade carcinoma (n = 24) were included in this study. Genomic DNA from each sample was extracted, amplified by conventional PCR, and analyzed through Sanger sequencing. Analysis for the expression of PIK3CA, Akt, p-Akt, and PTEN was performed by immunohistochemistry, and of Akt2 by RNA in situ hybridization. Results: PIK3CA H1047R mutation was detected in 14.3% (10/70) of tumor samples. Dysregulation of p-Akt, Akt2, and PTEN was observed in mammary tumor samples, but only PTEN dysregulation was associated with PIK3CA H1047R mutation. Conclusions: The present study showed that dysregulation of components in the PI3K/Akt/PTEN pathway is a feature of canine mammary tumors, but this dysregulation is not directly correlated to the PIK3CA H1047R mutation except for PTEN expression.
Synergy between Phage Sb-1 and Oxacillin against Methicillin-Resistant Staphylococcus aureus
Authors: Simon Kevin , Pier Wolfgang , Krüttgen Alex , Horz Hans-Peter
Published: July 2021

Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious pathogen responsible for not only a number of difficult-to-treat hospital-acquired infections, but also for infections that are community- or livestock-acquired. The increasing lack of efficient antibiotics has renewed the interest in lytic bacteriophages (briefly phages) as additional antimicrobials against multi-drug resistant bacteria, including MRSA. The aim of this study was to test the hypothesis that a combination of the well-known and strictly lytic S. aureus phage Sb-1 and oxacillin, which as sole agent is ineffective against MRSA, exerts a significantly stronger bacterial reduction than either antimicrobial alone. Eighteen different MRSA isolates and, for comparison, five MSSA and four reference strains were included in this study. The bacteria were challenged with a combination of varying dosages of the phage and the antibiotic in liquid medium using five different antibiotic levels and four different viral titers (i.e., multiplicity of infections (MOIs) ranging from 10−5 to 10). The dynamics of the cell density changes were determined via time-kill assays over 16 h. Positive interactions between both antimicrobials in the form of facilitation, additive effects, or synergism were observed for most S. aureus isolates. These enhanced antibacterial effects were robust with phage MOIs of 10−1 and 10 irrespective of the antibiotic concentrations, ranging from 5 to 100 µg/mL. Neutral effects between both antimicrobials were seen only with few isolates. Importantly, antagonism was a rare exception. As a conclusion, phage Sb-1 and oxacillin constitute a robust heterologous antimicrobial pair which extends the efficacy of a phage-only approach for controlling MRSA.
Evolutionary 3D Image Segmentation of Curve Epithelial Tissues of Drosophila melanogaster
Authors: Capitán-Agudo Carlos , Pontes Beatriz , Gómez-Gálvez Pedro , Vicente-Munuera Pablo
Published: July 2021

Analysing biological images coming from the microscope is challenging; not only is it complex to acquire the images, but also the three-dimensional shapes found on them. Thus, using automatic approaches that could learn and embrace that variance would be highly interesting for the field. Here, we use an evolutionary algorithm to obtain the 3D cell shape of curve epithelial tissues. Our approach is based on the application of a 3D segmentation algorithm called LimeSeg, which is a segmentation software that uses a particle-based active contour method. This program needs the fine-tuning of some hyperparameters that could present a long number of combinations, with the selection of the best parametrisation being highly time-consuming. Our evolutionary algorithm automatically selects the best possible parametrisation with which it can perform an accurate and non-supervised segmentation of 3D curved epithelial tissues. This way, we combine the segmentation potential of LimeSeg and optimise the parameters selection by adding automatisation. This methodology has been applied to three datasets of confocal images from Drosophila melanogaster, where a good convergence has been observed in the evaluation of the solutions. Our experimental results confirm the proper performing of the algorithm, whose segmented images have been compared to those manually obtained for the same tissues.
Towards Quantum 3D Imaging Devices
Authors: Abbattista Cristoforo , Amoruso Leonardo , Burri Samuel , Charbon Edoardo , Di Lena Francesco , Garuccio Augusto , Giannella Davide , Hradil Zdeněk , Iacobellis Michele , Massaro Gianlorenzo , Mos Paul , Motka Libor , Paúr Martin , Pepe Francesco V. , Peterek Michal , Petrelli Isabella , Řeháček Jaroslav , Santoro Francesca , Scattarella Francesco , Ulku Arin , Vasiukov Sergii , Wayne Michael , Bruschini Claudio , D’Angelo Milena , Ieronymaki Maria , Stoklasa Bohumil
Published: July 2021

We review the advancement of the research toward the design and implementation of quantum plenoptic cameras, radically novel 3D imaging devices that exploit both momentum–position entanglement and photon–number correlations to provide the typical refocusing and ultra-fast, scanning-free, 3D imaging capability of plenoptic devices, along with dramatically enhanced performances, unattainable in standard plenoptic cameras: diffraction-limited resolution, large depth of focus, and ultra-low noise. To further increase the volumetric resolution beyond the Rayleigh diffraction limit, and achieve the quantum limit, we are also developing dedicated protocols based on quantum Fisher information. However, for the quantum advantages of the proposed devices to be effective and appealing to end-users, two main challenges need to be tackled. First, due to the large number of frames required for correlation measurements to provide an acceptable signal-to-noise ratio, quantum plenoptic imaging (QPI) would require, if implemented with commercially available high-resolution cameras, acquisition times ranging from tens of seconds to a few minutes. Second, the elaboration of this large amount of data, in order to retrieve 3D images or refocusing 2D images, requires high-performance and time-consuming computation. To address these challenges, we are developing high-resolution single-photon avalanche photodiode (SPAD) arrays and high-performance low-level programming of ultra-fast electronics, combined with compressive sensing and quantum tomography algorithms, with the aim to reduce both the acquisition and the elaboration time by two orders of magnitude. Routes toward exploitation of the QPI devices will also be discussed.
Ultrasound-Assisted Extraction of Flavonoids from Kiwi Peel: Process Optimization and Bioactivity Assessment
Authors: Giordano Miguel , Pinela José , Dias Maria Inês , Calhelha Ricardo C. , Stojković Dejan , Soković Marina , Tavares Débora , Cánepa Analía Laura , Ferreira Isabel C. F. R. , Caleja Cristina , Barros Lillian
Published: July 2021

The nutritional quality of kiwifruit has been highlighted by several studies, while its peel is typically discarded as a by-product with no commercial value. This study was carried out to optimize the ultrasound-assisted extraction (UAE) of phenolic compounds from kiwi peel. Three independent variables (time (t), ultrasonic power (P) and ethanol concentration (EtOH)) were combined in a five-level central composite rotatable design coupled with the response surface methodology (RSM). The extraction yield determined gravimetrically and the content of phenolic compounds identified by HPLC-DAD-ESI/MSn (namely two quercetin glycosides, one catechin isomer and one B-type (epi)catechin dimer) were the experimental responses used in the optimization. The polynomial models were successfully fitted to the experimental data and used to determine the optimal UAE conditions. The sonication of the sample at 94.4 W for 14.8 min, using 68.4% ethanol, resulted in a maximum of 1.51 ± 0.04 mg of flavonoids per g of extract, a result that allowed the experimental validation of the predictive model. The kiwi peel extract obtained under optimized conditions showed somehow promising bioactive properties, including antioxidant and antimicrobial effects, and no toxicity to Vero cells. Overall, this study contributes to the valorization of kiwi peel as a low-cost raw material for the development of natural ingredients (such as food preservatives) and also to the resource-use efficiency and circular bioeconomy.
Audio Enhancement of Physical Models of Musical Instruments Using Optimal Correction Factors: The Recorder Case
Authors: Bakogiannis Konstantinos , Polychronopoulos Spyros , Marini Dimitra , Kouroupetroglou Georgios
Published: July 2021

A simulation of a musical instrument is considered to be a successful one when there is a good resemblance between the model’s synthesized sound and the real instrument’s sound. In this work, we propose the integration of physical modeling (PM) methods with an optimization process to regulate a generated digital signal. Its goal is to find a new set of values of the PM’s parameters’ that would lead to a synthesized signal matching as much as possible to reference signals corresponding to the physical musical instrument. The reference signals can be: (a) described by their acoustic characteristics (e.g., fundamental frequencies, inharmonicity, etc.) and/or (b) the signals themselves (e.g., impedances, recordings, etc.). We put this method into practice for a commercial recorder, simulated using the digital waveguides’ PM technique. The reference signals, in our case, are the recorded signals of the physical instrument. The degree of similarity between the synthesized (PM) and the recorded signal (musical instrument) is calculated by the signals’ linear cross-correlation. Our results show that the adoption of the optimization process resulted in more realistic synthesized signals by (a) enhancing the degree of similarity between the synthesized and the recorded signal (the average absolute Pearson Correlation Coefficient increased from 0.13 to 0.67), (b) resolving mistuning issues (the average absolute deviation of the synthesized from the recorded signals’ pitches reduced from 40 cents to the non-noticeable level of 2 cents) and (c) similar sound color characteristics and matched overtones (the average absolute deviation of the synthesized from the recorded signals’ first five partials reduced from 41 cents to 2 cents).
Variational Quantum Circuits for Machine Learning. An Application for the Detection of Weak Signals
Authors: Griol-Barres Israel , Milla Sergio , Cebrián Antonio , Mansoori Yashar , Millet José
Published: July 2021

Quantum computing is a new paradigm for a multitude of computing applications. This study presents the technologies that are currently available for the physical implementation of qubits and quantum gates, establishing their main advantages and disadvantages and the available frameworks for programming and implementing quantum circuits. One of the main applications for quantum computing is the development of new algorithms for machine learning. In this study, an implementation of a quantum circuit based on support vector machines (SVMs) is described for the resolution of classification problems. This circuit is specially designed for the noisy intermediate-scale quantum (NISQ) computers that are currently available. As an experiment, the circuit is tested on a real quantum computer based on superconducting qubits for an application to detect weak signals of the future. Weak signals are indicators of incipient changes that will have a future impact. Even for experts, the detection of these events is complicated since it is too early to predict this impact. The data obtained with the experiment shows promising results but also confirms that ongoing technological development is still required to take full advantage of quantum computing.
Malicious Powershell Detection Using Graph Convolution Network
Authors: Choi Sunoh
Published: July 2021

The internet’s rapid growth has resulted in an increase in the number of malicious files. Recently, powershell scripts and Windows portable executable (PE) files have been used in malicious behaviors. To solve these problems, artificial intelligence (AI) based malware detection methods have been widely studied. Among AI techniques, the graph convolution network (GCN) was recently introduced. Here, we propose a malicious powershell detection method using a GCN. To use the GCN, we needed an adjacency matrix. Therefore, we proposed an adjacency matrix generation method using the Jaccard similarity. In addition, we show that the malicious powershell detection rate is increased by approximately 8.2% using GCN.
Behavioural Responses of Cerastoderma edule as Indicators of Potential Survival Strategies in the Face of Flooding Events
Authors: Verdelhos Tiago , Veríssimo Helena , Marques João Carlos , Anastácio Pedro
Published: July 2021

According to climate change scenarios the incidence of extreme events, such as flooding, is expected to increase worldwide. In the current climate change context, understanding behavioural responses of marine species to such stressors is essential, especially for species of high ecological and economic interest such as bivalves, which can be quite useful for future management and conservation actions. In this study, a laboratory experiment using different salinity conditions was undertaken to assess potential behavioural responses of cockles (Cerastoderma edule), as a survival strategy facing low-salinity stress during riverine flood events. Results showed consistent patterns of burrowing/emergence of cockles facing salinity variation: with high salinities the individuals were observed buried in the sediment; when salinity decreased, organisms were observed to actively emerge, and when salinity was <10, cockles were found exposed at the sediment surface. These behavioural changes may be a strategy for the survival of this species in response to flooding: once at the sediment surface, hydrodynamics may transport organisms towards areas that are more suitable
Optimization of Truck-Drone Parcel Delivery Using Metaheuristics
Authors: AlMuhaideb Sarab , Alhussan Taghreed , Alamri Sara , Altwaijry Yara , Aljarbou Lujain , Alrayes Haifa
Published: July 2021

This research addresses a variant of the traveling salesman problem in drone-based delivery systems known as the TSP-D. The TSP-D is a combinatorial optimization problem in which a truck and a drone collaborate to deliver parcels to customers, with the objective of minimizing the total delivery time. Determining the optimal solution is NP-hard; thus, the size of the problems that can be solved optimally is limited. Therefore, metaheuristics are used to solve the problem. Metaheuristics are adaptive and intelligent algorithms that have proved their success in many similar problems. In this study, a solution to the TSP-D problem using the greedy, randomized adaptive search procedure with two local search alternatives and a self-adaptive neighborhood selection scheme is presented. The proposed approach was tested on 200 instances with different properties from the publicly available “Instances of TSP with Drone” benchmark. Results were evaluated against state-of-the-art algorithms. Non-parametric statistical tests concluded that the proposed approach has comparable performance to the rival algorithms (p=0.074) in terms of tour duration. The proposed approach has better or similar performance in instances where the drone and truck have the same speed (α=1).
On the Electron Impact Integral Cross-Sections for Butanol and Pentanol Isomers
Authors: Uddin Nafees , Modak Paresh , Antony Bobby
Published: July 2021

The need for a reliable and comprehensive database of cross-sections for many atomic and molecular species is immense due to its key role in R&D domains such as plasma modelling, bio-chemical processes, medicine and many other natural and technological environments. Elastic, momentum transfer and total cross-sections of butanol and pentanol isomers by the impact of 6–5000 eV electrons are presented in this work. The calculations were performed by employing the spherical complex optical potential formalism along with single-centre expansion and group additivity rule. The investigations into the presence of isomeric variations reveal that they are more pronounced at low and intermediate energies. Elastic, total cross-sections (with the exception of n-pentanol) and momentum transfer cross-sections for all pentanol isomers are reported here for the first time, to the best of our knowledge. Our momentum transfer cross-sections for butanol isomers are in very good agreement with the experimental and theoretical values available, and in reasonable consensus for other cross-sections.
Molecular Basis for Mechanical Properties of ECMs: Proposed Role of Fibrillar Collagen and Proteoglycans in Tissue Biomechanics
Authors: Silver Frederick H. , Kelkar Nikita , Deshmukh Tanmay
Published: July 2021

Collagen and proteoglycans work in unison in the ECM to bear loads, store elastic energy and then dissipate excess energy to avoid tissue fatigue and premature mechanical failure. While collagen fibers store elastic energy by stretching the flexible regions in the triple helix, they do so by lowering their free energy through a reduction in the entropy and a decrease in charge–charge repulsion. Entropic increases occur when the load is released that drive the reversibility of the process and transmission of excess energy. Energy is dissipated by sliding of collagen fibrils by each other with the aid of decorin molecules that reside on the d and e bands of the native D repeat pattern. Fluid flow from the hydration layer associated with the decorin and collagen fibrils hydraulically dissipates energy during sliding. The deformation is reversed by osmotic forces that cause fluid to reform a hydration shell around the collagen fibrils when the loads are removed. In this paper a model is presented describing the organization of collagen fibers in the skin and cell–collagen mechanical relationships that exist based on non-invasive measurements made using vibrational optical coherence tomography. It is proposed that under external stress, collagen fibers form a tensional network in the plane of the skin. Collagen fiber tension along with forces generated by fibroblasts exerted on collagen fibers lead to an elastic modulus that is almost uniform throughout the plane of the skin. Tensile forces acting on cells and tissues may provide a baseline for stimulation of normal mechanotransduction. We hypothesize that during aging, changes in cellular metabolism, cell–collagen interactions and light and UV light exposure cause down regulation of mechanotransduction and tissue metabolism leading to tissue atrophy.
Optical Microscopy and the Extracellular Matrix Structure: A Review
Authors: Poole Joshua J. A. , Mostaço-Guidolin Leila B.
Published: July 2021

Biological tissues are not uniquely composed of cells. A substantial part of their volume is extracellular space, which is primarily filled by an intricate network of macromolecules constituting the extracellular matrix (ECM). The ECM serves as the scaffolding for tissues and organs throughout the body, playing an essential role in their structural and functional integrity. Understanding the intimate interaction between the cells and their structural microenvironment is central to our understanding of the factors driving the formation of normal versus remodelled tissue, including the processes involved in chronic fibrotic diseases. The visualization of the ECM is a key factor to track such changes successfully. This review is focused on presenting several optical imaging microscopy modalities used to characterize different ECM components. In this review, we describe and provide examples of applications of a vast gamut of microscopy techniques, such as widefield fluorescence, total internal reflection fluorescence, laser scanning confocal microscopy, multipoint/slit confocal microscopy, two-photon excited fluorescence (TPEF), second and third harmonic generation (SHG, THG), coherent anti-Stokes Raman scattering (CARS), fluorescence lifetime imaging microscopy (FLIM), structured illumination microscopy (SIM), stimulated emission depletion microscopy (STED), ground-state depletion microscopy (GSD), and photoactivated localization microscopy (PALM/fPALM), as well as their main advantages, limitations.
Effects of Autologous Bone Marrow Mesenchymal Stem Cells and Platelet-Rich Plasma on Bone Regeneration and Osseointegration of a Hydroxyapatite-Coated Titanium Implant
Authors: Salamanna Francesca , Del Piccolo Nicolandrea , Sartori Maria , Giavaresi Gianluca , Martini Lucia , Di Sante Giuseppe , Stagni Cesare , Dallari Dante , Fini Milena
Published: July 2021

Bone regeneration remains one of the major clinical needs in orthopedics, and advanced and alternative strategies involving bone substitutes, cells, and growth factors (GFs) are mandatory. The purpose of this study was to evaluate whether the association of autologous bone marrow mesenchymal stem cells (BMSC), isolated by ‘one-step surgical procedure’, and activated platelet rich plasma (PRP) improves osseointegration and bone formation of a hydroxyapatite-coated titanium (Ti-HA) implant, already in clinical use, in a rabbit cancellous defect. The GFs present in plasma, in inactivated and activated PRP were also tested. At 2 weeks, histology and histomorphometry highlighted increased bone-to-implant contact (BIC) in Ti-HA combined with BMSC and PRP in comparison to Ti-HA alone and Ti-HA + PRP. The combined effect of BMSC and PRP peaked at 4 weeks where the BIC value was higher than all other treatments. At both experimental times, newly formed bone (Trabecular Bone Volume, BV/TV) in all tested treatments showed increased values in comparison to Ti-HA alone. At 4 weeks Ti-HA + PRP + BMSC showed the highest BV/TV and the highest osteoblasts number; additionally, a higher osteoid surface and bone formation rate were found in Ti-HA + BMSC + PRP than in all other treatments. Finally, the analyses of GFs revealed higher values in the activated PRP in comparison to plasma and to non-activated PRP. The study suggests that the combination of autologous activated PRP, as a carrier for BMSCs, is a promising regenerative strategy for bone formation, osseointegration, and mineralization of bone implants.
Improving the Tensile Properties of Additively Manufactured β-Containing TiAl Alloys via Microstructure Control Focusing on Cellular Precipitation Reaction
Authors: Cho Ken , Odo Hirotaka , Okamoto Keisuke , Yasuda Hiroyuki Y. , Nakashima Hirotoyo , Takeyama Masao , Nakano Takayoshi
Published: July 2021

The effect of a two-step heat treatment on the microstructure and high-temperature tensile properties of β-containing Ti-44Al-4Cr (at%) alloys fabricated by electron beam powder bed fusion were examined by focusing on the morphology of α2/γ lamellar grains and β/γ cells precipitated at the lamellar grain boundaries by a cellular precipitation reaction. The alloys subjected to the first heat treatment step at 1573 K in the α + β two-phase region exhibit a non-equilibrium microstructure consisting of the α2/γ lamellar grains with a fine lamellar spacing and a β/γ duplex structure located at the grain boundaries. In the second step of heat treatment, i.e., aging at 1273 K in the β + γ two-phase region, the β/γ cells are discontinuously precipitated from the lamellar grain boundaries due to excess Cr supersaturation in the lamellae. The volume fraction of the cells and lamellar spacing increase with increasing aging time and affect the tensile properties of the alloys. The aged alloys exhibit higher strength and comparable elongation at 1023 K when compared to the as-built alloys. The strength of these alloys is strongly dependent on the volume fraction and lamellar spacing of the α2/γ lamellae. In addition, the morphology of the β/γ cells is also an important factor controlling the fracture mode and ductility of these alloys.
Study on Ultrasonically-Enhanced Sulfuric Acid Leaching of Nickel from Nickel-Containing Residue
Authors: Guo Zhanyong , Guo Ping , Su Guang , Li Fachuang
Published: July 2021

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.
Co-Crystallization Kinetics of 2:1 Benzoic Acid–Sodium Benzoate Co-Crystal: The Effect of Templating Molecules in a Solution
Authors: Lini Freshsya Zata , Pratama Dhanang Edy , Lee Tu
Published: July 2021

The addition of dissolved templating molecules in crystallization will create “supramolecular assemblies” within the solution, serving as “anchor points” for the solute molecules to nucleate and grow. In this work, nucleation and crystal growth kinetics of 2:1 benzoic acid (HBz)–sodium benzoate (NaBz) co-crystallization with or without templates in a solution were analyzed by monitoring the concentration of the mother liquor during cooling crystallization. The results showed that the addition of the dissolved 2:1 or 1:1 HBz–NaBz co-crystals as templating molecules could reduce the critical free energy barrier of 2:1 HBz–NaBz co-crystal during its nucleation, but did not significantly affect the order of crystal growth rate. On the other hand, the critical free energy barrier of the nucleation process was increased if dissolved NaBz was used as a templating molecule, while a significant rise in the order of crystal growth rate occurred. The crystal habit obtained from the NaBz-templated system was needle-like, suggesting that sodium–sodium coordination chains of NaBz supramolecular assemblies in the solution phase were responsible for creating elongated crystals. Conversely, a large prismatic crystal habit found in non-templated and 2:1 and 1:1 HBz–NaBz co-crystal-templated systems implied that those templating molecules formed sparsely interconnected supramolecular assemblies in the solution phase.
Limitation of Screening of Different Variants of SARS-CoV-2 by RT-PCR
Authors: Boudet Agathe , Stephan Robin , Bravo Sophie , Sasso Milène , Lavigne Jean-Philippe
Published: July 2021

Since January 2021, the diffusion of the most propagated SARS-CoV-2 variants in France (UK variant 20I/501Y.V1 (lineage B.1.1.7), 20H/H501Y.V2 (lineage B.1.351) and 20J/H501Y.V3 (lineage P.1)) were urgently screened, needing a surveillance with an RT-PCR screening assay. In this study, we evaluated one RT-PCR kit for this screening (ID SARS-CoV-2/UK/SA Variant Triplex®, ID Solutions, Grabels, France) on 2207 nasopharyngeal samples that were positive for SARS-CoV-2. Using ID Solutions kit, 4.1% (92/2207) of samples were suspected to belonged to B.1.351 or P.1 variants. Next-generation sequencing that was performed on 67.4% (62/92) of these samples confirmed the presence of a B.1.351 variant in only 75.8% of the samples (47/62). Thirteen samples belonged to the UK variant (B.1.1.7), and two to A.27 with N501Y mutation. The thirteen with the UK variant presented one mutation in the S-gene, near the ΔH69/ΔV70 deletion (S71F or A67S), which impacted the detection of ΔH69/ΔV70 deletion. Using another screening kit (PKampVariantDetect SARS-CoV-2 RT-PCR combination 1 and 3® PerkinElmer, Waltham, MA, USA) on the misidentified samples, we observed that the two mutations, S71F or A67S, did not impact the detection of the UK variant. In conclusion, this study highlights the limitations of the screening strategy based on the detection of few mutations/deletions as well as it not being able to follow the virus evolution.
Optimal Utility of H-Reflex RDD as a Biomarker of Spinal Disinhibition in Painful and Painless Diabetic Neuropathy
Authors: Worthington Anne , Kalteniece Alise , Ferdousi Maryam , D’Onofrio Luca , Dhage Shaishav , Azmi Shazli , Adamson Clare , Hamdy Shaheen , Malik Rayaz A. , Calcutt Nigel A. , Marshall Andrew G.
Published: July 2021

Impaired rate-dependent depression of the Hoffman reflex (HRDD) is a potential biomarker of impaired spinal inhibition in patients with painful diabetic neuropathy. However, the optimum stimulus-response parameters that identify patients with spinal disinhibition are currently unknown. We systematically compared HRDD, performed using trains of 10 stimuli at five stimulation frequencies (0.3, 0.5, 1, 2 and 3 Hz), in 42 subjects with painful and 62 subjects with painless diabetic neuropathy with comparable neuropathy severity, and 34 healthy controls. HRDD was calculated using individual and mean responses compared to the initial response. At stimulation frequencies of 1, 2 and 3 Hz, HRDD was significantly impaired in patients with painful diabetic neuropathy compared to patients with painless diabetic neuropathy for all parameters and for most parameters when compared to healthy controls. HRDD was significantly enhanced in patients with painless diabetic neuropathy compared to controls for responses towards the end of the 1 Hz stimulation train. Receiver operating characteristic curve analysis in patients with and without pain showed that the area under the curve was greatest for response averages of stimuli 2–4 and 2–5 at 1 Hz, AUC = 0.84 (95%CI 0.76–0.92). Trains of 5 stimuli delivered at 1 Hz can segregate patients with painful diabetic neuropathy and spinal disinhibition, whereas longer stimulus trains are required to segregate patients with painless diabetic neuropathy and enhanced spinal inhibition.
Predictors of College Enrollment across the Life Course: Heterogeneity by Age and Gender
Authors: Monaghan David B.
Published: July 2021

Undergraduate college-going is now undertaken well into adulthood, but knowledge about what leads individuals to enroll derives nearly entirely from the study of the “traditionally-aged”. I examine whether and how predictors of enrollment vary as individuals progress through the life-course using nationally representative data from the United States, following a cohort from ages 18–45. Measures of social background and academic preparation are only weakly predictive beyond age 24, while the effects of gender are largest after age 35. Marriage appears to be a barrier to enrollment among males and females, but only until age 25. Involuntary job loss spurs college-going most strongly among those aged 35 or older, and particularly among women. Among those over age 25, marital dissolution predicts enrollment positively among females but negatively among males.
Computation of Lightning Current from Electric Field Based on Laplace Transform and Deconvolution Method
Authors: Karnas Grzegorz
Published: July 2021

A method for computation of the lightning channel base current from the corresponding vertical component of lightning electric field was presented. The algorithm was developed by applying Laplace transform. The lightning current was estimated from its deconvolution with a special transfer function. The transfer function includes information about geometry and physical properties of entire lightning impulse generation system. The method was verified for a Heidler-type base current and a MTLL model of its propagation within the lightning channel. Research was done for close, middle, and far distance to the lightning strike point. Optimum performance was obtained for the middle distance of several kilometers where the electrostatic, induction, and radiation components of the transfer function were of the same range. An analysis was done for input electric field with and without noise superimposed on its time domain waveform. Relative uncertainties for the electric field and calculated lightning channel base current were similar each other. The presented approach can substantially increase a number of lightning current parameters which can be identified on the basis of its electric field signature. This method can be applied by the lightning location systems using preprocessing which increases the timing efficiency of the transfer function estimation.
An Artificial Intelligence Empowered Cyber Physical Ecosystem for Energy Efficiency and Occupation Health and Safety
Authors: Koutroumpinas Petros , Zhang Yu , Wallis Steve , Chang Elizabeth
Published: July 2021

Reducing energy waste is one of the primary concerns facing Remote Industrial Plants (RIP) and, in particular, the accommodations and operational plants located in remote areas. With the COVID-19 pandemic continuing to attack the health of workforce, managing the balance between energy efficiency and Occupation Health and Safety (OHS) in the workplace becomes another great challenge for the RIP. Maintaining this balance is difficult mainly because a full awareness of the OHS will generally consume more energy while reducing the energy cost may lead to a less effective OHS, and the existing literature has not seen a system that is designed for the RIPs to conserve energy usage and improve workforce OHS simultaneously. To bridge this gap, in this paper, we propose an AI Empowered Cyber Physical Ecosystem (AECPE) solution for the RIPs, which integrates Cyber-Physical Systems (CPS), artificial intelligence, and mobile networks. The preliminary results of lab experiments and field tests proved that the AECPE was able to help industries reduce the corporate annual energy cost that is worth millions of dollars, optimise the environmental conditions, and improve OHS for all workers and stakeholders. The implementation of the AECPE can result in efficient energy usage, reduced wastage and emissions, environment-friendly operations, and improved social reputation of the industries.
Improvement of a Diagnostic Urban Wind Model for Flow Fields around a Single Rectangular Obstacle in Micrometeorology Simulation
Authors: Asami Mitsufumi , Kimura Arata , Oka Hideyuki
Published: July 2021

In general, computational fluid dynamics (CFD) models incur high computational costs when dealing with realistic and complicated flows. In contrast, the mass-consistent flow (MASCON) field model provides a three-dimensional flow field at reasonable computational cost. Unfortunately, some weaknesses in simulating the flow of the wake zone exist because the momentum equations are not considered in the MASCON field model. In the present study, a new set of improved algebraic models to provide initial flow fields for the MASCON field model are proposed to overcome these weaknesses by considering the effect of momentum diffusion in the wake zone. Specifically, these models for the wake region are developed on the basis of the wake models used in well-recognized Gaussian plume models, ADMS-build and PRIME. The MASCON fields provided by the new set of wake zone models are evaluated against wind-tunnel experimental data on flow around a wall-mounted rectangular obstacle. Each MASCON field is compared with the experimental results, focusing on the positions of the vortex core and saddle points of the vortex formed in the near-wake zone and the vertical velocity distribution in the far-wake zone. The set of wake zone models developed in the present study better reproduce the experimental results in both the wake zones compared to the previously proposed models. In particular, the complicated recirculation flow which is formed by the union of the sidewall recirculation zone and the near-wake zone is reproduced by the present wake zone model using the PRIME model that includes the parameterization of the sidewall recirculation zones.
Vibration Systems with Fractional-Order and Distributed-Order Derivatives Characterizing Viscoinertia
Authors: Duan Jun-Sheng , Hu Di-Chen
Published: July 2021

We considered forced harmonic vibration systems with the Liouville–Weyl fractional derivative where the order is between 1 and 2 and with a distributed-order derivative where the Liouville–Weyl fractional derivatives are integrated on the interval [1, 2] with respect to the order. Both types of derivatives enhance the viscosity and inertia of the system and contribute to damping and mass, respectively. Hence, such types of derivatives characterize the viscoinertia and represent an “inerter-pot” element. For such vibration systems, we derived the equivalent damping and equivalent mass and gave the equivalent integer-order vibration systems. Particularly, for the distributed-order vibration model where the weight function was taken as an exponential function that involved a parameter, we gave detailed analyses for the weight function, the damping contribution, and the mass contribution. Frequency–amplitude curves and frequency-phase curves were plotted for various coefficients and parameters for the comparison of the two types of vibration models. In the distributed-order vibration system, the weight function of the order enables us to simultaneously involve different orders, whilst the fractional-order model has a single order. Thus, the distributed-order vibration model is more general and flexible than the fractional vibration system.
Selection and Implementation of Intelligent Transportation Systems for Work Zone Construction Projects
Authors: Azimi Mehdi , Oyelade Ibukunoluwa , Aremu Akintola Moses , Balal Esmaeil , Cheu Ruey Long , Qi Yi
Published: July 2021

The extent of the deployment of Intelligent Transportation Systems (ITSs) for work zone construction projects has increased in recent years. However, highway agencies are unable to meet the full demand of the deployment of ITSs in work zones in a fiscally constrained environment. Therefore, it is desirable to establish guidelines to help highway agencies to consider installing ITS in work zones as funding becomes available. The goal of this research is to develop a methodology and guideline to assist project designers in assessing whether a particular work zone construction or maintenance project should be considered for the deployment of one or more ITSs. If so, the guideline would assist in determining the ITSs that would be most appropriate for the project. To achieve this goal, the researchers: (1) investigated technologies and evaluated different ITSs that could be used in work zone projects, (2) selected the criteria that would have to be evaluated to identify the eligible work zone projects for the deployment of ITSs, and (3) developed a selection methodology to assist project designers in selecting one or more work zone ITSs in order to be deployed in the project. The outcomes of this study provide a guideline for use in selecting and implementing ITSs for a work zone construction or maintenance project.
A Multi-Analytical Study of an Ancient Egyptian Limestone Stele for Knowledge and Conservation Purposes: Recovering Hieroglyphs and Figurative Details by Image Analysis
Authors: Cavaleri Tiziana , Legnaioli Stefano , Lozar Francesca , Comina Cesare , Poole Federico , Pelosi Claudia , Spoladore Alessia , Castelli Daniele , Palleschi Vincenzo
Published: July 2021

A multi-analytical study was carried out on an ancient Egyptian limestone stele with red figures and hieroglyphs (S. 6145) coming from the village of Deir el-Medina and belonging to the collection of the Museo Egizio (Turin, Italy). With the support of a multidisciplinary team, a project for the preservation and conservation of this stele provided an opportunity to carry out a very detailed study of the object. Petrographic and mineralogical analysis led to the characterization and dating of the limestone, and ultrasonic tests were of great help in shedding light on the state of preservation of the stele, as a preliminary to planning conservation treatment. The chemical nature of the red pigment was investigated by non-invasive spectroscopic analyses. Multispectral imaging and statistical image processing improved the readability of the hieroglyphs, whose preservation ranged from heavily compromised to almost completely invisible, revealing some signs that had previously not been visible.