bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructural Characteristics of Arc Beads with Overcurrent Fault in the Fire Scene
Authors: Yu Zhijin , Chen Shuangshuang , Deng Jun , Xu Xueyan , Wang Weifeng
Published: October 2020

Arc beads are high-temperature luminous electric discharges that form across a gap between two bodies, which is one of the vital forensic pieces of evidence for the evaluation of electrical fires. In this study, based on an actual electrical fire, the microstructure of arc beads from a copper wire that experienced an overcurrent fault was investigated by optical microscopy and scanning electron microscopy. Moreover, the effects of the overcurrent intensity on the grain morphology, trace elements, and microstructure of the arc beads were analyzed. The results showed that the simulated metallographic structure of the arc beads is mainly dendrite at four times the rated current, which is consistent with the fire scene. With an increase in the overcurrent, the average diameter, perimeter, and area of the grains increased, while the dendrite growth was inhibited by the overcurrent. In addition, the main trace elements were Cu, C, O, and Cl. When the current increased, the Cu content gradually decreased and tended to be stable, while the C content gradually increased. The conclusion of this research provided a scientific reference for identifying the melting trace in a copper conductor under overcurrent fault.
Achieving the Minimum Roughness of Laser Milled Micro-Impressions on Ti 6Al 4V, Inconel 718, and Duralumin
Authors: Ahmed Naveed , Rehman Ateekh Ur , Ishfaq Kashif , Naveed Rakhshanda , Moiduddin Khaja , Umer Usama , E Ragab Adham , Al-Zabidi Ayoub
Published: October 2020

Titanium-aluminium-vanadium (Ti 6Al 4V) alloys, nickel alloys (Inconel 718), and duraluminum alloys (AA 2000 series) are widely used materials in numerous engineering applications wherein machined features are required to having good surface finish. In this research, micro-impressions of 12 µm depth are milled on these materials though laser milling. Response surface methodology based design of experiment is followed resulting in 54 experiments per work material. Five laser parameters are considered naming lamp current intensity (I), pulse frequency (f), scanning speed (V), layer thickness (LT), and track displacement (TD). Process performance is evaluated and compared in terms of surface roughness through several statistical and microscopic analysis. The significance, strength, and direction of each of the five laser parametric effects are deeply investigated for the said alloys. Optimized laser parameters are proposed to achieve minimum surface roughness. For the optimized combination of laser parameters to achieve minimum surface roughness (Ra) in the titanium alloy, the said alloy consists of I = 85%, f = 20 kHz, V = 250 mm/s, TD = 11 µm, and LT = 3 µm. Similarly, optimized parameters for nickel alloy are as follows: I = 85%, f = 20 kHz, V = 256 mm/s, TD = 8 µm, and LT = 1 µm. Minimum roughness (Ra) on the surface of aluminum alloys can be achieved under the following optimized parameters: I = 75%, f = 20 kHz, V = 200 mm/s, TD = 12 µm, and LT = 3 µm. Micro-impressions produced under optimized parameters have surface roughness of 0.56 µm, 2.46 µm, and 0.54 µm on titanium alloy, nickel alloy, and duralumin, respectively. Some engineering applications need to have high surface roughness (e.g., in case of biomedical implants) or some desired level of roughness. Therefore, validated statistical models are presented to estimate the desired level of roughness against any laser parametric settings.
Diamond-Coated Plasma Probes for Hot and Hazardous Plasmas
Authors: Ionita Codrina , Schrittwieser Roman , Xu Guosheng , Yan Ning , Wang Huiqian , Naulin Volker , Rasmussen Jens Juul , Steinmüller-Nethl Doris
Published: October 2020

Plasma probes are simple and inexpensive diagnostic tools for fast measurements of relevant plasma parameters. While in earlier times being employed mainly in relatively cold laboratory plasmas, plasma probes are now routinely used even in toroidal magnetic fusion experiments, albeit only in the edge region, i.e., the so-called scrape-off layer (SOL), where temperature and density of the plasma are lower. To further avoid overheating and other damages, in medium-size tokamak (MST) probes are inserted only momentarily by probe manipulators, with usually no more than a 0.1 s per insertion during an average MST discharge of a few seconds. However, in such hot and high-density plasmas, their usage is limited due to the strong particle fluxes onto the probes and their casing which can damage the probes by sputtering and heating and by possible chemical reactions between plasma particles and the probe material. In an attempt to make probes more resilient against these detrimental effects, we tested two graphite probe heads (i.e., probe casings with probes inserted) coated with a layer of electrically isolating ultra-nano-crystalline diamond (UNCD) in the edge plasma region of the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, People’s Republic of China. The probe heads, equipped with various graphite probe pins, were inserted frequently even into the deep SOL up to a distance of 15 mm inside the last closed flux surface (LCFS) in low- and high-confinement regimes (L-mode and H-mode). Here, we concentrate on results most relevant for the ability to protect the graphite probe casings by UNCD against harmful effects from the plasma. We found that the UNCD coating also prevented almost completely the sputtering of graphite from the probe casings and thereby the subsequent risk of re-deposition on the boron nitride isolations between probe pins and probe casings by a layer of conductive graphite. After numerous insertions into the SOL, first signs of detachment of the UNCD layer were noticed.
Chasing the Bubble: Ultrasonic Dispersion and Attenuation from Cement with Superabsorbent Polymers to Shampoo
Authors: Lefever Gerlinde , Ospitia Nicolas , Serafin Dorian , Hemelrijck Danny Van , Aggelis Dimitrios G.
Published: October 2020

This study aims to experimentally investigate the ultrasonic behavior of fresh cement focusing on the contribution of the entrapped air bubbles. Frequency dispersion and attenuation carry delicate information that is not possible to gather by traditional ultrasonic pulse velocity. This is measured by simple indicators that quantify the frequency dependence of propagation velocity of longitudinal waves through fresh cementitious media. It seems that dispersion shows much stronger sensitivity to the microstructural processes, since the presence of superabsorbent polymers in mortar induces a large difference in dispersion parameters when compared to reference cement mortar, while only marginal difference in threshold-based pulse velocity. To reach this aim, references are taken from, and comparisons are made to other liquids in order first in order to validate the reliability of the methodology and to better understand the contribution of the cavities in the obtained dispersion and attenuation curves. Ultrasonic dispersion assessment of cementitious media has the potential to bring a lot of information on the microstructure of materials, as well as the ongoing processes.
Impulse Response of the Elasto-Hydrodynamic Lubrication Film of a Rolling Bearing to Dynamic Excitation of a Flat Belt Drive
Authors: Adamčík Pavel , Murčinková Zuzana
Published: October 2020

The impulse response of a rolling bearing and its principal component, the elasto-hydrodynamic lubrication film (EHDL), are analysed. When measuring the vibrations of bearings, we observed that the impulse response was mostly caused by defects (fatigue damage) on the raceways and/or rolling elements. However, this phenomenon can also occur in new defect-free roller bearings, where it is not commonly expected. This study presents an experiment that identifies the conditions of dynamic excitation for the impulse response of the EHDL, the source of which is not defects, but the EHDL itself. The EHDL responds in the form of impulses in case the velocity of its radial deformation is too fast. This is an unfavourable phenomenon that significantly shortens the service life of bearings. To analyse the dynamic excitation conditions, a testing bench at speeds up to 135,000 rpm with a flat belt drive was used. The testing bench enabled the formation of the so-called beat excitation from two harmonic excitation forces close in rotational frequency. The subject of this study is a defect-free high-speed double-row angular contact ball bearing used in the textile industry. We also present other physical conditions for the occurrence of undesired impulse responses that are caused by the EHDL.
Role of PVDF in Rheology and Microstructure of NCM Cathode Slurries for Lithium-Ion Battery
Authors: Sung Sang Hoon , Kim Sunhyung , Park Jeong Hoon , Park Jun Dong , Ahn Kyung Hyun
Published: October 2020

A binder plays a critical role in dispersion of coating liquids and the quality of coating. Poly(vinylidene fluoride) (PVDF) is widely used as a binder in cathode slurries; however, its role as a binder is still under debate. In this paper, we study the role of PVDF on the rheology of cathode battery slurries consisting of Li(Ni1/3Mn1/3Co1/3)O2 (NCM), carbon black (CB) and N-methyl-2-pyrrolidone (NMP). Rheology and microstructure of cathode slurries are systemically investigated with three model suspensions: CB/PVDF/NMP, NCM/PVDF/NMP and NCM/CB/PVDF/NMP. To highlight the role of PVDF in cathode slurries, we prepare the same model suspensions by replacing PVDF with PVP, and we compare the role of PVDF to PVP in the suspension rheology. We find that PVDF adsorbs neither onto NCM nor CB surface, which can be attributed to its poor affinity to NCM and CB. Rheological measurements suggest that PVDF mainly increases matrix viscosity in the suspension without affecting the microstructure formed by CB and NCM particles. In contrast to PVDF, PVP stabilizes the structure of CB and NCM in the model suspensions, as it is adsorbed on the CB surface. This study will provide a useful insight to fundamentally understand the rheology of cathode slurries.
Effects of CeO2 Content on Friction and Wear Properties of SiCp/Al-Si Composite Prepared by Powder Metallurgy
Authors: Yang Bin , Wang Aiqin , Liu Kunding , Liu Chenlu , Xie Jingpei , Wang Guangxin , Wei Shizhong
Published: October 2020

SiCp/Al-Si composites with different CeO2 contents were prepared by a powder metallurgy method. The effect of CeO2 content on mechanical properties, friction and wear properties of the composites was studied. The results show that with the increase in CeO2 content from 0 to 1.8 wt%, the density, hardness, friction coefficient of the composites first increases and then decreases, the coefficient of thermal expansion (CTE) and wear rate of the composites first decreases and then increases. When the content of CeO2 was 0.6 wt%, the density and hardness of the composite reached the maximum value of 98.54% and 113.7 HBW, respectively, the CTE of the composite reached the minimum value of 11.1 × 10−6 K−1, the friction coefficient and wear rate of the composite reached the maximum value of 0.32 and the minimum value of 1.02 mg/m, respectively. CeO2 has little effect on the wear mechanism of composites, and the wear mechanism of composites with different CeO2 content is mainly abrasive wear under the load of 550 N. Compared with the content of CeO2, load has a great influence on the wear properties of the composites. The wear mechanism of the composites is mainly oxidation wear and abrasive wear under low load. With the increase in load, the wear degree of abrasive particles is aggravated, and adhesive wear occurs under higher load.
The Effect of Microwave on the Crystallization Behavior of CMAS System Glass-Ceramics
Authors: Li Hangren , Liu Saiyu , Xu Wence , Zhang Yuxuan , Li Xin , Ouyang Shunli , Zhao Guangkai , Liu Fang , Wu Nannan
Published: October 2020

The microwave sintering of glass-ceramics, non-thermal microwave effect, and crystal growth mechanism remain important challenges in materials science. In this study, we focus on developing approaches to affect crystal growth in the glass network of glass-ceramics by microwave heating, rather than performing a single study on the crystal structure and type. Raman spectroscopy is used to detect the structure of the glass network. We demonstrated that the non-thermal microwave effect promoted the diffusion of metal ions, which promoted the aggregation and precipitation of metal ions in the glass network to form crystals. The samples produced by microwave heating contain more non-bridging oxygen bonds than conventional sintered samples; therefore, the non-thermal microwave effect has a depolymerization effect on the glass network of the sample. Under the influence of microwave field, many metal ions precipitate, which precipitates many crystal nuclei. In addition, many active metal ions are captured during the crystal nucleus growth, which shortens the sintering process of glass-ceramics.
Bacterial Cellulose (Komagataeibacter rhaeticus) Biocomposites and Their Cytocompatibility
Authors: Petrova Valentina A. , Khripunov Albert K. , Golovkin Alexey S. , Mishanin Alexander I. , Gofman Iosif V. , Romanov Dmitry P. , Migunova Alexandra V. , Arkharova Natalia A. , Klechkovskaya Vera V. , Skorik Yury A.
Published: October 2020

A series of novel polysaccharide-based biocomposites was obtained by impregnation of bacterial cellulose produced by Komagataeibacter rhaeticus (BC) with the solutions of negatively charged polysaccharides—hyaluronan (HA), sodium alginate (ALG), or κ-carrageenan (CAR)—and subsequently with positively charged chitosan (CS). The penetration of the polysaccharide solutions into the BC network and their interaction to form a polyelectrolyte complex changed the architecture of the BC network. The structure, morphology, and properties of the biocomposites depended on the type of impregnated anionic polysaccharides, and those polysaccharides in turn determined the nature of the interaction with CS. The porosity and swelling of the composites increased in the order: BC–ALG–CS > BC–HA–CS > BC–CAR–CS. The composites show higher biocompatibility with mesenchymal stem cells than the original BC sample, with the BC–ALG–CS composite showing the best characteristics.
IR Study on Cellulose with the Varied Moisture Contents: Insight into the Supramolecular Structure
Authors: Cichosz Stefan , Masek Anna
Published: October 2020

The following article is the first attempt to investigate the supramolecular structure of cellulose with the varied moisture content by the means of Fourier-transform and near infrared spectroscopy techniques. Moreover, authors aimed at the detailed and precise presentation of IR spectra interpretation approach in order to create a reliable guideline for other researchers. On the basis of obtained data, factors indicating biopolymer crystallinity and development of hydrogen interactions were calculated and the peaks representing hydrogen bonding (7500–6000 cm−1, 3700–3000 cm−1, and 1750–1550 cm−1) were resolved using the Gaussian distribution function. Then, the deconvoluted signals have been assigned to the specific interactions occurring at the supramolecular level and the hydrogen bond length, as well bonding-energy were established. Furthermore, not only was the water molecules adsorption observed, but also the possibility of the 3OH⋯O5 intramolecular hydrogen bond shortening in the wet state was found-from (27,786 ± 2) 10−5 nm to (27,770 ± 5) 10−5 nm. Additionally, it was proposed that some deconvoluted signals from the region of 3000–2750 cm−1 might be assigned to the hydroxyl group-incorporated hydrogen bonding, which is, undoubtedly, a scientific novelty as the peak was not resolved before.
Uniformly Resolvable Decompositions of Kv-I into n-Cycles and n-Stars, for Even n
Authors: Lo Faro Giovanni , Milici Salvatore , Tripodi Antoinette
Published: October 2020

If X is a connected graph, then an X-factor of a larger graph is a spanning subgraph in which all of its components are isomorphic to X. Given a set Γ of pairwise non-isomorphic graphs, a uniformly resolvable Γ-decomposition of a graph G is an edge decomposition of G into X-factors for some graph X∈Γ. In this article we completely solve the existence problem for decompositions of Kv-I into Cn-factors and K1,n-factors in the case when n is even.
Least Squares Approximation of Flatness on Riemannian Manifolds
Authors: Hirica Iulia , Udriste Constantin , Pripoae Gabriel , Tevy Ionel
Published: October 2020

The purpose of this paper is fourfold: (i) to introduce and study the Euler–Lagrange prolongations of flatness PDEs solutions (best approximation of flatness) via associated least squares Lagrangian densities and integral functionals on Riemannian manifolds; (ii) to analyze some decomposable multivariate dynamics represented by Euler–Lagrange PDEs of least squares Lagrangians generated by flatness PDEs and Riemannian metrics; (iii) to give examples of explicit flat extremals and non-flat approximations; (iv) to find some relations between geometric least squares Lagrangian densities.
The Combined Estimator for Stochastic Equations on Graphs with Fractional Noise
Authors: Kříž Pavel , Szała Leszek
Published: October 2020

In the present paper, we study the problem of estimating a drift parameter in stochastic evolution equations on graphs. We focus on equations driven by fractional Brownian motions, which are particularly useful e.g., in biology or neuroscience. We derive a novel estimator (the combined estimator) and prove its strong consistency in the long-span asymptotic regime with a discrete-time sampling scheme. The promising performance of the combined estimator for finite samples is examined under various scenarios by Monte Carlo simulations.
Multi-Stage Change Point Detection with Copula Conditional Distribution with PCA and Functional PCA
Authors: Kim Jong-Min , Wang Ning , Liu Yumin
Published: October 2020

A global uncertainty environment, such as the COVID-19 pandemic, has affected the manufacturing industry severely in terms of supply and demand balancing. So, it is common that one stage statistical process control (SPC) chart affects the next-stage SPC chart. It is our research objective to consider a conditional case for the multi-stage multivariate change point detection (CPD) model for highly correlated multivariate data via copula conditional distributions with principal component analysis (PCA) and functional PCA (FPCA). First of all, we review the current available multivariate CPD models, which are the energy test-based control chart (ETCC) and the nonparametric multivariate change point model (NPMVCP). We extend the current available CPD models to the conditional multi-stage multivariate CPD model via copula conditional distributions with PCA for linear normal multivariate data and FPCA for nonlinear non-normal multivariate data.
Complex Tasks: Potentials and Pitfalls
Authors: Bohlmann Nina , Benölken Ralf
Published: October 2020

Life in today’s world is characterized by complexity and rapid change. Twenty-first century skills and especially mathematical understanding are supposed to crucially contribute to meeting the demands of our world since mathematics offers strategies to structure or simplify complex problems. An open question is which teaching practices are appropriate to provide all students with such skills and to broaden the participation of underprivileged students. The present article explores these aspects by focusing on complex tasks, a practice that can be considered highly accepted in the context of mathematics education all over the world. We will concentrate on the perspective of the German mathematics education community as the foundation of our considerations. Based on an analytical investigation of mathematical literacy and twenty-first century skills (such as creativity, critical thinking, or problem-solving), we will address central ideas and characteristics of complex mathematical tasks. To complement the analytical approach, we will illustrate their characteristics as well as possible intersections with twenty-first century skills by presenting an elementary school teaching experiment. Finally, we will critically discuss the potentials and pitfalls of complex mathematical tasks from an abstract perspective and conclude by debating practical consequences for organizing mathematical learning-teaching-processes.
Investigations on Tailored Forming of AISI 52100 as Rolling Bearing Raceway
Authors: Coors Timm , Mildebrath Maximilian , Büdenbender Christoph , Saure Felix , Faqiri Mohamad Yusuf , Kahra Christoph , Prasanthan Vannila , Chugreeva Anna , Matthias Tim , Budde Laura , Pape Florian , Nürnberger Florian , Hassel Thomas , Hermsdorf Jörg , Overmeyer Ludger , Breidenstein Bernd , Denkena Berend , Behrens Bernd-Arno , Maier Hans Jürgen , Poll Gerhard
Published: October 2020

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 is generally regarded as non-weldable, it could be applied as a cladding material by adjusting PTA parameters. The cladded parts were investigated after each individual process step and subsequently tested under rolling contact load. Welding defects that could not be completely eliminated by the subsequent hot forming were characterized by means of scanning acoustic microscopy and micrographs. Below the surface, pores with a typical size of ten µm were found to a depth of about 0.45 mm. In the material transition zone and between individual weld seams, larger voids were observed. Grinding of the surface after heat treatment caused compressive residual stresses near the surface with a relatively small depth. Fatigue tests were carried out on an FE8 test rig. Eighty-two percent of the calculated rating life for conventional bearings was achieved. A high failure slope of the Weibull regression was determined. A relationship between the weld defects and the fatigue behavior is likely.
Use of the Critical Acidification Model to Estimate the Influence of W in the Localized Corrosion Resistance of 25Cr Super Duplex Stainless Steels
Authors: Torres Cristian , Iannuzzi Mariano , Johnsen Roy
Published: October 2020

Two super duplex stainless steels (SDSS) with different W content, namely UNS S32750 (W-free) and UNS S39274 (2.1 wt.% W), were tested in simulated crevice corrosion environments to determine the influence of W on their corrosion resistance. Anodic potentiodynamic polarization experiments were performed in two different crevice-like-solutions: 1 M HCl (as reference for a pH = 0 environment), and 7 M LiCl, adjusted to the same pH value. Galvele’s critical acidification model was used to estimate the theoretical critical potential (Ecrit) and comparatively evaluate the corrosion resistance of the two SDSS. The anodic potentiodynamic polarization results showed a statistically significant difference between the two materials in only one test condition, i.e., 7 M Cl− at 60 °C. Additionally, the quantification of chemical dissolution of the metal cations after the tests suggested a surface enrichment in W only in the 7 M chloride solution. Scanning electron microscope (SEM) analysis indicated a uniform dissolution experienced by UNS S32750 in this environment, whereas UNS S39274 suffered selective corrosion of the ferrite-phase. These observations were reflected in a slight increase in the Ecrit values of UNS S32974 estimated with Galvele’s model.
Microstructural Evolution and Mechanical Properties of Hybrid Bevel Gears Manufactured by Tailored Forming
Authors: Behrens Bernd-Arno , Chugreeva Anna , Diefenbach Julian , Kahra Christoph , Herbst Sebastian , Nürnberger Florian , Maier Hans Jürgen
Published: October 2020

The production of multi-metal bulk components requires suitable manufacturing technologies. On the example of hybrid bevel gears featuring two different steels at the outer surface and on the inside, the applicability of the novel manufacturing technology of Tailored Forming was investigated. In a first processing step, a semi-finished compound was manufactured by cladding a substrate using a plasma transferred arc welding or a laser hotwire process. The resulting semi-finished workpieces with a metallurgical bond were subsequently near-net shape forged to bevel gears. Using the residual heat after the forging process, a process-integrated heat treatment was carried out directly after forming. For the investigations, the material combinations of 41Cr4 with C22.8 (AISI 5140/AISI 1022M) and X45CrSi9-3 with C22.8 (AISI HNV3/AISI 1022M) were applied. To reveal the influence of the single processing steps on the resulting interface, metallographic examinations, hardness measurements and micro tensile tests were carried out after cladding, forging and process-integrated heat treatment. Due to forging and heat-treatment, recrystallization and grain refinement at the interface and an increase in both, hardness and tensile strength, were observed.
A Comparison Between Semisolid Casting Methods for Aluminium Alloys
Authors: Jarfors Anders E. W.
Published: October 2020

Semisolid casting of aluminium alloys is growing. For magnesium alloys, Thixomoulding became the dominant process around the world. For aluminium processing, the situation is different as semisolid processing of aluminium is more technically challenging than for magnesium. Today three processes are leading the process implementation, The Gas-Induced Superheated-Slurry (GISS) method, the RheoMetal process and the Swirling Enthalpy Equilibration Device (SEED) process. These processes have all strengths and weaknesses and will fit a particular range of applications. The current paper aims at looking at the strengths and weaknesses of the processes to identify product types and niche applications for each process based on current applications and development directions taken for these processes.
Impact of Yeast-Derived β-Glucans on the Porcine Gut Microbiota and Immune System in Early Life
Authors: de Vries Hugo , Geervliet Mirelle , Jansen Christine A. , Rutten Victor P. M. G. , van Hees Hubèrt , Groothuis Natalie , Wells Jerry M. , Savelkoul Huub F. J. , Tijhaar Edwin , Smidt Hauke
Published: October 2020

Piglets are susceptible to infections in early life and around weaning due to rapid environmental and dietary changes. A compelling target to improve pig health in early life is diet, as it constitutes a pivotal determinant of gut microbial colonization and maturation of the host’s immune system. In the present study, we investigated how supplementation of yeast-derived β-glucans affects the gut microbiota and immune function pre- and post-weaning, and how these complex systems develop over time. From day two after birth until two weeks after weaning, piglets received yeast-derived β-glucans or a control treatment orally and were subsequently vaccinated against Salmonella Typhimurium. Faeces, digesta, blood, and tissue samples were collected to study gut microbiota composition and immune function. Overall, yeast-derived β-glucans did not affect the vaccination response, and only modest effects on faecal microbiota composition and immune parameters were observed, primarily before weaning. This study demonstrates that the pre-weaning period offers a ‘window of opportunity’ to alter the gut microbiota and immune system through diet. However, the observed changes were modest, and any long-lasting effects of yeast-derived β-glucans remain to be elucidated.
On the Sensitivity of the Ni-rich Layered Cathode Materials for Li-ion Batteries to the Different Calcination Conditions
Authors: Ronduda Hubert , Zybert Magdalena , Szczęsna-Chrzan Anna , Trzeciak Tomasz , Ostrowski Andrzej , Szymański Damian , Wieczorek Władysław , Raróg-Pilecka Wioletta , Marcinek Marek
Published: October 2020

Ni-rich layered oxides, i.e., LiNi0.6Mn0.2Co0.2O2 (NMC622) and LiNiO2 (LNO), were prepared using the two-step calcination procedure. The samples obtained at different calcination temperatures (750–950 °C for the NMC622 and 650–850 °C for the LNO cathode materials) were characterized using nitrogen physisorption, PXRD, SEM and DLS methods. The correlation of the calcination temperature, structural properties and electrochemical performance of the studied Ni-rich layered cathode materials was thoroughly investigated and discussed. It was determined that the optimal calcination temperature is dependent on the chemical composition of the cathode materials. With increasing nickel content, the optimal calcination temperature shifts towards lower temperatures. The NMC-900 calcined at 900 °C and the LNO-700 calcined at 700 °C showed the most favorable electrochemical performances. Despite their well-ordered structure, the materials calcined at higher temperatures were characterized by a stronger sintering effect, adverse particle growth, and higher Ni2+/Li+ cation mixing, thus deteriorating their electrochemical properties. The importance of a careful selection of the heat treatment (calcination) temperature for each individual cathode material was emphasized.
Bacteriophage Cocktail for the Prevention of Multiple-Antibiotic-Resistant and Mono-Phage-Resistant Vibrio coralliilyticus Infection in Pacific Oyster (Crassostrea gigas) Larvae
Authors: Kim Hyoun Joong , Jun Jin Woo , Giri Sib Sankar , Kim Sang Guen , Kim Sang Wha , Kwon Jun , Lee Sung Bin , Chi Cheng , Park Se Chang
Published: October 2020

Vibrio coralliilyticus (V. coralliilyticus) is a pathogen that causes mass mortality in marine bivalve hatcheries worldwide. In this study, we used a bacteriophage (phage) cocktail to prevent multiple-antibiotic-resistant (MAR) and phage-resistant (PR) V. coralliilyticus infection in Pacific oyster (Crassostreagigas) larvae. To prevent the occurrence of phage-resistant strains and decrease the effect of mono-phage treatment, we prepared a phage cocktail containing three types of V. coralliilyticus-specific phages and tested its prophylactic efficacy against MAR and PR V. coralliilyticus infection. The results of the cell lysis test showed that the phage cocktail showed an excellent bactericidal effect against the MAR and PR variants in contrast to the experimental group treated with two mono phages (pVco-5 and pVco-7). An in vivo test using Pacific oyster larvae also confirmed the preventive effect against MAR and PR variants. In conclusion, the application of the phage cocktail effectively prevented V. coralliilyticus infection in marine bivalve seedling production. Furthermore, it is expected to reduce damage to the aquaculture industry caused by the occurrence of MAR and PR V. coralliilyticus. Therefore, phage cocktails may be used for the control of various bacterial diseases.
Clinical Characteristics of Acute Hepatitis E and Their Correlation with HEV Genotype 3 Subtypes in Italy
Authors: Minosse Claudia , Biliotti Elisa , Lapa Daniele , Rianda Alessia , Marchili Mauro , Luzzitelli Ilaria , Capobianchi Maria Rosaria , McPhee Fiona , Garbuglia Anna Rosa , D’Offizi Gianpiero
Published: October 2020

Genotype 3 (GT3) is responsible for most European autochthonous hepatitis E virus (HEV) infections. This study analyzed circulating genotypes and GT3 subtypes in the Lazio region, Italy, between 2011 and 2019, as well as their pathogenic characteristics. Of the 64 evaluable HEV GT3 patient-derived sequences, identified subtypes included GT3f (n = 36), GT3e (n = 15), GT3c (n = 9), GT3a (n = 1) and three unsubtyped GT3 sequences. GT3c strains were similar to Dutch sequences (96.8–98.1% identity), GT3e strains showed high similarity (96.8%) with a United Kingdom sequence, while the most related sequences to GT3f Italian strains were isolated in France, Belgium and Japan. One sequence was closely related to another Italian strain isolated in raw sewage in 2016. The liver functioning test median values for 56 evaluable GT3 patients were: alanine aminotransferase (ALT), 461 (range 52–4835 U/L); aspartate aminotransferase (AST), 659 (range 64–6588 U/L); and total bilirubin, 3.49 (range 0.4–33 mg/dL). The median HEV RNA viral load for 26 evaluable GT3 patients was 42,240 IU/mL (range 5680–895,490 IU/mL). Of the 37 GT3 patients with available clinical information, no correlation was observed between HEV clinical manifestations and GT3 subtype. HEV symptoms were comparable among GT3c/e/f patients across most analyzed categories except for epigastric pain, which occurred more frequently in patients with HEV GT3e (75%) than in patients with GT3c (50%) or GT3f (19%) (p = 0.01). Additionally, patients with HEV GT3c exhibited significantly higher median international normalized ratio (INR) than patients with GT3e and GT3f (p = 0.033). The severity of GT3 acute hepatitis E was not linked to HEV RNA viral load or to the GT3 subtype.
Insights into Genomic Epidemiology, Evolution, and Transmission Dynamics of Genotype VII of Class II Newcastle Disease Virus in China
Authors: Xiang Bin , Chen Libin , Cai Juncheng , Liang Jianpeng , Lin Qiuyan , Xu Chenggang , Ding Chan , Liao Ming , Ren Tao
Published: October 2020

Newcastle disease virus (NDV) is distributed worldwide and has caused significant losses to the poultry industry. Almost all virulent NDV strains belong to class II, among which genotype VII is the predominant genotype in China. However, the molecular evolution and phylodynamics of class II genotype VII NDV strains in China remained largely unknown. In this study, we identified 13 virulent NDV including 11 genotype VII strains and 2 genotype IX strains, from clinical samples during 1997 to 2019. Combined NDV sequences submitted to GenBank, we investigate evolution, and transmission dynamics of class II NDVs in China, especially genotype VII strains. Our results revealed that East and South China have the most genotypic diversity of class II NDV, and East China might be the origin of genotype VII NDVs in China. In addition, genotype VII NDVs in China are presumably transmitted by chickens, as the virus was most prevalent in chickens. Furthermore, codon usage analysis revealed that the F genes of genotype VII NDVs have stronger adaptation in chickens, and six amino acids in this gene are found under positive selection via selection model analysis. Collectively, our results revealed the genetic diversity and evolutionary dynamics of genotype VII NDVs in China, providing important insights into the epidemiology of these viruses in China.
Green-Yellow-Orange-Red Spectral Range with Sum-Frequency Generation Using BIBO Crystal Pumped with an Optical Parametric Amplifier
Authors: Quintero-Torres Rafael , Domínguez-Juárez Jorge Luis
Published: October 2020

In this letter, we show the broadband sum-frequency generation (SFG) in the Green-Yellow-Orange-Red spectral range using bismuth triborate, BiB3O6 crystal (BIBO) as a nonlinear material. We perform a noncollinear phase-matching configuration within the BIBO crystal using the remaining light behind the second harmonic generation stage and the infrared idler of an optical parametric amplifier (OPA). The obtained mixing radiation of ultrafast light sources to generate femtosecond pulses across the 520.5 to 742.5 nm region is observed. The SFG spectrum from a single-pass cross-correlation intensity over such visible range is shown. The SFG wavelengths as a function of the tunable wavelength idler OPA agree with the expectations of the parametric conversion condition and open the door to practical multi-beam or multi-color sum-frequency generators.
Development and Analysis of a Modular LED Array Light Source
Authors: Mitterhofer Stefan , Korošak Žiga , Rojec Žiga , Jankovec Marko , Topič Marko
Published: October 2020

Light emitting diodes (LEDs) have experienced rapid technological development in the past decade, making them a winning alternative to conventional light sources in many applications. LED arrays allow precise control of the desired irradiance profile in a target area by adjusting the position and output power of individual LEDs. However, despite increased efficiency, many LEDs still transform a large proportion of the input electrical power into heat, requiring an efficient cooling system. This paper presents a modular LED array light source mounted on a water-cooled aluminum plate. Novel electronic LED driver modules, connected via a serial communication bus in a daisy-chain topology, were developed with the ability to set the operating current of individual LEDs. A modular layout of cooling and mounting system and LED driver modules, as well as a specialized design for the LED soldering footprint, was able to house a variety of common commercial LEDs, enabling easy adjustment of the lighting system to the required application and size of the irradiated area. In a prototype of one plate containing 10 LEDs, individual LED radiance was optimized for a better irradiance homogeneity in the target area. Array characterization showed a low standard deviation of the irradiance of 1.8% and a good fit between measured and calculated irradiance. A test of the array at elevated temperatures showed moderate LED radiance degradation and a wavelength shift of the measured spectra after extended use.
Successful Treatment of a COVID-19 Case with Pneumonia and Renal Injury Using Tocilizumab
Authors: Ashino Yugo , Chagan-Yasutan Haorile , Hatta Masumitsu , Shirato Yoichi , Kyogoku Yorihiko , Komuro Hanae , Hattori Toshio
Published: October 2020

A 49-year-old male Japanese patient was admitted to our hospital under the diagnosis of COVID-19 pneumonia. For 5 days before admission, he had experienced various symptoms, including high fever, watery diarrhea, dyspnea, and cough, and he tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid. The patient is a smoker who was on medication for hypertension. A chest computed tomography scan showed bilateral multiple patchy ground-glass opacities. Despite being treated with several therapeutic agents, he still exhibited dyspnea (oxygen saturation [SpO2] in ambient air: 88%), a high fever (axillary temperature: 39 °C), and high blood pressure (148/98 mmHg). Because laboratory data revealed high levels of C-reactive protein (CRP; 2.10 mg/dL) and urinary β2-microglobulin (B2M; 33,683 µg/mL), the anti-interleukin-6 receptor antibody tocilizumab (TCZ; 400 mg) was administered intravenously. One day after injection, he was afebrile. Four days after the TCZ injection, his CRP level dropped to 0.27 mg/dL, B2M level decreased to 3817 µg/mL, and viral load became low. No adverse drug reaction due to TCZ was observed. The patient was discharged 15 days after admission. The early administration of TCZ in this patient prevented the pneumonia and kidney injury caused by COVID-19 from progressing to hyperinflammation syndrome.
Does Training Improve Sanitary Inspection Answer Agreement between Inspectors? Quantitative Evidence from the Mukono District, Uganda
Authors: King Richard , Okurut Kenan , Herschan Jo , Lapworth Dan J. , Malcolm Rosalind , McKeown Rory Moses , Pond Katherine
Published: October 2020

Sanitary inspections (SIs) are checklists of questions used for achieving/maintaining the safety of drinking-water supplies by identifying observable actual and potential sources and pathways of contamination. Despite the widespread use of SIs, the effects of training on SI response are understudied. Thirty-six spring supplies were inspected on two occasions, pre- and post-training, by an instructor from the research team and four local inspectors in the Mukono District of Uganda. SI score agreement between the instructor and each inspector was calculated using Lin’s concordance correlation coefficient. Average SI score agreement between the instructor and all inspectors increased post-training for the Yes/No answer type (0.262 to 0.490). For the risk level answer type (e.g., No, Low, Medium, High), average SI score agreement between the instructor and all inspectors increased post-training (0.301 to 0.380). Variability of SI scores between the four inspectors was calculated using coefficient of variation analysis. Average SI score variability between inspectors reduced post-training for both answer types, Yes/No (21.25 to 16.16) and risk level (24.12 to 19.62). Consistency of answer agreement between the four inspectors for each individual SI question was calculated using index of dispersion analysis. Average answer dispersion between inspectors reduced post-training for both answer types, Yes/No (0.41 to 0.27) and risk level (0.55 to 0.41). The findings indicate that training has a positive effect on improving answer agreement between inspectors. However, advanced training or tailoring of SI questions to the local context may be required where inconsistency of responses between inspectors persists, especially for the risk level answer type that requires increased use of inspector risk perception. Organisations should be aware of the potential inconsistency of results between inspectors so that this may be rectified with appropriate training and, where necessary, better SI design and customisation.
The Effect of the FIRST Robotics Program on Its Graduates
Authors: Rocker Yoel Shahaf , Shwartz Asher Daphna , Schohet Maayan , Dori Yehudit Judy
Published: October 2020

The program For Inspiration and Recognition of Science and Technology (FIRST) for young students incorporates project-based learning (PBL) with designing and building wireless-controlled robots. The students are guided by experts, mostly engineers. The FIRST organization determines the theme of the robot annual competition. The goal of this research is to characterize and evaluate the effect of the FIRST program on graduates’ self-efficacy, interpersonal skills, and career choices in science, technology, engineering, and mathematics (STEM). The research participants included 297 FIRST graduates, mostly high schoolers, who responded to questionnaires, and five of them were interviewed. Analysis of the data showed that the FIRST program improved graduates’ interpersonal skills such as time management, teamwork skills, and self-efficacy, as well as had an impact on the graduates’ STEM career choices. The main factors impacting the graduates’ career choice was their exposure to robotics and to experts from the industry. The theoretical contribution is to the social cognitive theory (SCT) in the context of the FIRST program. Our study explains students’ career choice through correlations among students’ aspirations for choosing a career, their self-efficacy, their interpersonal skills, and their actual choice. The practical contribution lies in better understanding the robotic PBL program and expanding the STEM work force.
Preventive Effect of a Polyphenol-Rich Extract from Geranium sanguineum L. on Hepatic Drug Metabolism in Influenza Infected Mice
Authors: Abarova Silviya , Tancheva Lyubka , Nikolov Rumen , Serkedjieva Julia , Pavlova Elitsa , Bramanti Alessia , Nicoletti Ferdinando , Tzvetkov Nikolay T.
Published: October 2020

The decreased hepatic drug metabolism (predominately first phase) is one of the essential reasons for numerous side effects and for increased drug toxicity during influenza virus infection (IVI). The present study aims to investigate some mechanisms of the preventive effect of a standardized polyphenol complex from the medicinal plant Geranium sanguineum L. (PPhC) (10 mg/kg nasally). A verified experimental model of IVI A/Aichi/2/68 (H3N2) (4.5 lg LD50) in male ICR (Institute of Cancer Research, USA) mice was used. Changes in hepatic monooxygenase activities as well as nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome C reductase activity and cytochtome P450 content were studied on days 2, 6, 9, 21 of the infection together with thiobarbituric acid reactive substances in the liver supernatant. Our data clearly demonstrates that IVI affects all components of the electronic chain of cytochrome P-450. N-demethylases and hydroxylases as well as the activity of cytochrome C reductase and cytochtome P-450 content were decreased in the course of the virus infection. This implies that free radicals play an important role not only in the pathogenesis of IVI, but also in the modulation of the hepatic monooxygenase activity. This is also consistent with the established polyphenol complex PPhC from the medicinal plant Geranium sanguineum L. preventive effect against increased thiobarbituric acid reactive substances (TBARS)-levels. PPhC restored most of the monooxygenase activities that were inhibited in IVI animals, even over the control levels, probably via multiple mechanisms that may entail antioxidant activity and selective antiviral and protein-binding effects. In contrast to infected animals, in healthy mice, PPhC showed moderate reversible inhibitory effect on hepatic monooxygenase activities.
Voltammetric Behaviour of Drug Molecules as a Predictor of Metabolic Liabilities
Authors: Fuchigami Hikari , Bal Mandeep K. , Brownson Dale A. C. , Banks Craig E. , Jones Alan M.
Published: October 2020

Electron transfer plays a vital role in drug metabolism and underlying toxicity mechanisms. Currently, pharmaceutical research relies on pharmacokinetics (PK) and absorption, distribution, metabolism, elimination and toxicity (ADMET) measurements to understand and predict drug reactions in the body. Metabolic stability (and toxicity) prediction in the early phases of the drug discovery and development process is key in identifying a suitable lead compound for optimisation. Voltammetric methods have the potential to overcome the significant barrier of new drug failure rates, by giving insight into phase I metabolism events which can have a direct bearing on the stability and toxicity of the parent drug being dosed. Herein, we report for the first time a data-mining investigation into the voltammetric behaviour of reported drug molecules and their correlation with metabolic stability (indirectly measured via t½), as a potential predictor of drug stability/toxicity in vivo. We observed an inverse relationship between oxidation potential and drug stability. Furthermore, we selected and prepared short- (<10 min) and longer-circulation (>2 h) drug molecules to prospectively survey the relationship between oxidation potential and stability.