bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure Refinement by a Combination of Heat Treatment and Thixoforming Process Followed by Severe Plastic Deformation and Their Effects on Al-Si Alloy Hardness
Authors: Gebril Mohamed Abdelgawad , Omar Mohd Zaidi , Mohamed Intan Fadhlina , Othman Norinsan Kamil , Irfan Osama M.
Published: November 2022

This study fabricated a thixoformed Al-7% Si alloy using the cooling slope technique and subjected it to heat treatment before processing with severe plastic deformation to determine the effect of this combination method on the microstructure refinement and hardness of Al-Si alloys (300 Series). Each as-cast and thixoformed Al-Si alloy sample was subjected to equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) individually at room temperature before and after heat treatment. ECAP was conducted in a mould with a 120° channel angle via route A, and HPT was applied with 0.75 and 5 turns. The heat-treated thixoformed Al-Si alloy subjected to the HPT process had an ultra-fine grain microstructure and showed a fine and homogeneous redistribution of the eutectic phase in the Al matrix. For the as-cast alloy, the hardness of the heat-treated thixoformed Al-7% Si alloy increased from 63 HV to 124 and 215 Hv after two ECAP passes and five turns of HPT due to the reduced and redistributed eutectic phase in the Al matrix. Subjecting the Al-7% Si alloy to a combination of semisolid and heat treatment processes before subjecting it to severe plastic deformation resulted in microstructural refinement and improved the hardness of the Al-Si alloy. The results indicate that HPT is a more effective method than ECAP for increasing the hardness of the thixoformed Al-Si alloy due to microstructure refinement.
Optimization of Process Parameters for Powder Bed Fusion Additive Manufacturing Using a Linear Programming Method: A Conceptual Framework
Authors: Khaimovich Alexander , Balyakin Andrey , Oleynik Maxim , Meshkov Artem , Smelov Vitaly
Published: November 2022

At present, the selection of optimal technological parameters for laser powder bed fusion (LPBF) is determined by the requirements of the fusion process. The main parameters that are commonly varied include laser power (P), scanning speed (v), hatch spacing (h), and layer thickness (t). The productivity of the LPBF process (the increment in the fused volume of the material) is equal to the product of the last three parameters, and the mechanical properties are largely determined by the volumetric fusion energy density, which is equal to the ratio of laser power to productivity. While ensuring maximum process productivity, it is possible to obtain acceptable quality characteristics—mechanical properties, surface roughness, etc.—for a certain range of LPBF technological parameters. In these cases, several quality characteristics act as constraints on the optimization process, and productivity and the key quality characteristics become components of the objective function. Therefore, this article proposes a formalized representation of the optimization problem for the LPBF process, including the derivation of the objective function with the constraint matrix, and provides a solution to the problem using the linear programming (LP) method. The advantages of the proposed method include the guaranteed convergence of the solution with an unlimited number of constraints; the disadvantage concerns the adequacy of the solution, which is limited by a relatively narrow range of parameter changes. The proposed method was tested in determining the optimal LPBF parameters for an HN58MBYu powder LP model that included 13 constraints and an objective function with two target parameters. The obtained results made it possible to increase the productivity by 15% relative to the basic technological parameters.
Evaluation Method and Application of Cold Rolled Strip Flatness Quality Based on Multi-Objective Decision-Making
Authors: Wang Qiuna , Li Jingdong , Wang Xiaochen , Yang Quan , Wu Zedong
Published: November 2022

Flatness is a vital quality index that determines the dimensional accuracy of the cold-rolled strip. This paper designs a local shape wave extraction algorithm and a fuzzy classification algorithm for overall flatness defect classification based on cosine distance. By introducing the small displacement buckling theory of thin plates, the plate stress buckling model of overall and local shape waves is studied, and the critical buckling elongation difference of the overall shape and the local shape under the given conditions are obtained. Finally, using the multi-objective decision-making evaluation method, a comprehensive evaluation model of the flatness quality is established. The model is applied to the actual cold rolling production. The on-site flatness data are used to verify the flatness quality determination model both locally and overall. The results show that the model can accurately identify the local and overall flatness defects of cold-rolled strips, realizes the accurate identification and evaluation of the cold-rolled flatness quality, and provides strong support for the optimization of rolling process parameters and the improvement of the quality of thin strip products.
Atmospheric Corrosion Evolution of Carbon Steel AISI 1020 along a Longitude Transect in the Atacama Desert
Authors: Cáceres Luis , Soliz Alvaro , Galleguillos Felipe
Published: November 2022

Carbon steel AISI 1020 was exposed to environmental conditions along a transect of the Atacama Desert to gather experimental evidence to identify the local atmospheric mechanism that triggers corrosion through a buildup of water layer formation on the metal surface in addition to corrosion evolution. Coupons initially left in selected sites were periodically collected to determine weight loss and surface attributes by scanning electron microscopy and X-ray diffraction. In addition, meteorological conditions were measured in addition to a fog water collector in one site. During the study period, the predominant conditions were the absence of rain, clear skies, and large daily oscillations in temperature and relative humidity. The evidence indicates a water film formation on a metal surface either from a vertical water flux as fog water droplets and/or by the dew water harvesting mechanism. The uptakes of oxygen and chlorides during the corrosion process were highest in the coastal site P0 and gradually decreased with the increasing distance from the coast. This is attributed to both humidity and saline marine fog intrusion from the coast. The oxide layer evolved to form a compact layer with main constituents of lepidocrocite, goethite, and lesser amounts of akageneite. The corrosion depth can be modelled by a simple power function d=AtB with B < 1, indicating a deceleration process.
Microstructure Evolution Behavior of Spray-Deposited 7055 Aluminum Alloy during Hot Deformation
Authors: Feng Di , Xu Rui , Li Jichen , Huang Wenjie , Wang Jingtao , Liu Ying , Zhao Linxiang , Li Chengbo , Zhang Hao
Published: November 2022

The evolution behaviors of the second phase, substructure and grain of the spray-deposited 7055 aluminum alloy during hot compression at 300~470 °C were studied by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Results show that the AlZnMgCu phase resulting from the deposition process dissolves gradually with the increase in deformation temperature, but the Al7Cu2Fe phase remains unchanged. The plastic instability of the spray-deposited 7055 aluminum alloy occurs at 470 °C with a 1~5 s−1 strain rate range. Partial dynamic recrystallization (PDRX) adjacent to the original high angle grain boundaries (HAGBs) not only occurs at 300~400 °C with the low strain rates ranging from 0.001 to 0.1 s−1 but also at 450 °C with a high strain rate of 5 s−1. Continuous dynamic recrystallization (CDRX) appears at 450 °C with a low strain rate of 0.001 s−1. The primary nucleation mechanism of PDRX includes the rotation of the subgrain adjacent to the original HAGBs and the subgrain boundary migration. The homogeneous misorientation increase in subgrains is the crucial nucleation mechanism of CDRX. At 300~400 °C, the residual coarse particle stimulated (PSN) nucleation can also be observed.
Structural Phase Transformation of Rail Steel in Compression
Authors: Aksenova Krestina , Gromov Victor , Ivanov Yurii , Qin Rongshan , Vashchuk Ekaterina
Published: November 2022

The analysis of structure and defective substructure of rail steel in uniaxial compression to a degree of 50% is carried out. It is revealed that cold hardening has a multi-stage character and is accompanied by fragmentations of pearlite grains which is in field as the degree of deformation increases and reaches ≈ 0.4 volume of the foil studied at ε = 50%. The fragments being formed in ferrite plates are separated by low-angle boundaries. The average size of the fragmented ferrite decreases from 240 nm at ε = 15% to 200 nm at ε = 50%. Concurrently with the ferrite fragmentation, fragments of cementite are also observed. It is found that the sizes of the cementite fragments are in a range of 15 to 20 nm and depend weakly on the degree of sample deformation. The cementite fragmentation is caused by deformation-induced carbon dissolution and dislocation-induced fracture. The carbon atoms diffuse from cementite crystal to dislocations, which move through an interplanar space to form particles of tertiary cementite at nanoscale (2–4 nm). It is found that the increase in the degree of deformation is accompanied by a decrease in the scalar and an excess dislocation density. A physical interpretation of the observations has been given.
Atomistic Investigation of Titanium Carbide Ti8C5 under Impact Loading
Authors: Xia Kang , Zhan Haifei , Shao Jianli , Wang Jiaqiu , Zheng Zhuoqun , Zhang Xinjie , Li Zhiyong
Published: November 2022

Titanium carbides attract attention from both academic and industry fields because of their intriguing mechanical properties and proven potential as appealing candidates in the variety of fields such as nanomechanics, nanoelectronics, energy storage and oil/water separation devices. A recent study revealed that the presence of Ti8C5 not only improves the impact strength of composites as coatings, but also possesses significant strengthening performance as an interlayer material in composites by forming strong bonding between different matrices, which sheds light on the design of impact protection composite materials. To further investigate the impact resistance and strengthening mechanism of Ti8C5, a pilot Molecular Dynamics (MD) study utilizing comb3 potential is carried out on a Ti8C5 nanosheet by subjecting it to hypervelocity impacts. The deformation behaviour of Ti8C5 and the related impact resist mechanisms are assessed in this research. At a low impact velocity ~0.5 km/s, the main resonance frequency of Ti8C5 is 11.9 GHz and its low Q factor (111.9) indicates a decent energy damping capability, which would eliminate the received energy in an interfacial reflection process and weaken the shock waves for Ti8C5 strengthened composites. As the impact velocity increases above the threshold of 1.8 km/s, Ti8C5 demonstrates brittle behaviour, which is signified by its insignificant out-of-plane deformation prior to crack initiation. When tracking atomic Von Mises stress distribution, the elastic wave propagation velocity of Ti8C5 is calculated to be 5.34 and 5.90 km/s for X and Y directions, respectively. These figures are inferior compared with graphene and copper, which indicate slower energy delocalization rates and thus less energy dissipation via deformation is expected prior to bond break. However, because of its relatively small mass density comparing with copper, Ti8C5 presents superior specific penetration. This study provides a fundamental understanding of the deformation and penetration mechanisms of titanium carbide nanosheets under impact, which is crucial in order to facilitate emerging impact protection applications for titanium carbide-related composites.
Laser Beam Welding of CubeSat 1U Structure Parts Obtained by Powder Bed Fusion
Authors: Siqueira Rafael Humberto Mota de , Celentano Diego Javier , Lima Milton Sergio Fernandes de
Published: November 2022

This study contributes to a possible methodology for manufacturing CubeSats using additive manufacturing and laser beam welding. Titanium connectors were constructed by selective laser melting and electron beam melting and characterized from a topological point of view. The connectors can be joined to titanium tubes for the construction of CubeSats via laser spot welding. The fiber laser welds exhibited full penetration using pulses with 400 J of energy. The welds showed titanium acicular martensite grains with recesses and pores. The average hardness of the cast zone was 350 HV, which is close to the hardness of the connectors (400 HV) and more rigid than that of the tubes (100 HV). Spot welding has proven to be useful in resisting forces above 2000 N, which is sufficient for CubeSat frame space applications.
Running for Your Life: Metabolic Effects of a 160.9/230 km Non-Stop Ultramarathon Race on Body Composition, Inflammation, Heart Function, and Nutritional Parameters
Authors: Bizjak Daniel A. , Schulz Sebastian V. W. , John Lucas , Schellenberg Jana , Bizjak Roman , Witzel Jens , Valder Sarah , Kostov Tihomir , Schalla Jan , Steinacker Jürgen M. , Diel Patrick , Grau Marijke
Published: November 2022

Moderate endurance exercise leads to an improvement in cardiovascular performance, stress resilience, and blood function. However, the influence of chronic endurance exercise over several hours or days is still largely unclear. We examined the influence of a non-stop 160.9/230 km ultramarathon on body composition, stress/cardiac response, and nutrition parameters. Blood samples were drawn before (pre) and after the race (post) and analyzed for ghrelin, insulin, irisin, glucagon, cortisol, kynurenine, neopterin, and total antioxidant capacity. Additional measurements included heart function by echocardiography, nutrition questionnaires, and body impedance analyses. Of the 28 included ultra-runners (7f/21m), 16 participants dropped out during the race. The remaining 12 finishers (2f/10m) showed depletion of antioxidative capacities and increased inflammation/stress (neopterin/cortisol), while energy metabolism (insulin/glucagon/ghrelin) remained unchanged despite a high negative energy balance. Free fat mass, protein, and mineral content decreased and echocardiography revealed a lower stroke volume, left end diastolic volume, and ejection fraction post race. Optimizing nutrition (high-density protein-rich diet) during the race may attenuate the observed catabolic and inflammatory effects induced by ultramarathon running. As a rapidly growing discipline, new strategies for health prevention and extensive monitoring are needed to optimize the athletes’ performance.
Altered Urinary Metabolomics in Hereditary Angioedema
Authors: Wang Xue , Zhi Yuxiang
Published: November 2022

Hereditary angioedema (HAE) is a rare and potentially life-threatening disease with heterogeneous clinical symptoms. The metabolomic profile of HAE remains unknown. Uncovering the metabolic signatures of HAE may provide inspiration for a comprehensive understanding of HAE pathogenesis and may help explore potential new metabolic biomarkers. We performed a comprehensive metabolic analysis using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). Urine samples from 34 HAE patients and 82 healthy controls (HCs) were collected to characterize the metabolic signatures associated with HAE. The metabolomes of HAE patients carrying different mutation types were also compared. A total of 795 metabolites were accurately detected and quantified. We considered 73 metabolites as differential metabolites in HAE patients (with an importance in projection (VIP) value > 1.0, q-value < 0.05, and fold change (FC) ≥ 1.2 or FC ≤ 0.8). Several metabolites associated with riboflavin metabolism, the citrate cycle, oxidative stress, and inflammation, including xanthine, oxypurinol, vitamin B2, and isocitrate, were significantly altered in HAE patients. No significantly different metabolites were found in HAE patients carrying different mutation types. The present study highlights that metabolic disturbances in the purine metabolism, riboflavin metabolism, and TCA cycle may be involved in the pathogenesis of HAE. Although biochemical significance requires further experimental verification, these findings may help to identify novel candidate metabolite biomarkers associated with HAE.
Integration of Liver Glycogen and Triglyceride NMR Isotopomer Analyses Provides a Comprehensive Coverage of Hepatic Glucose and Fructose Metabolism
Authors: Viegas Ivan , Di Nunzio Giada , Belew Getachew D. , Torres Alejandra N. , Silva João G. , Perpétuo Luis , Barosa Cristina , Tavares Ludgero C. , Jones John G.
Published: November 2022

Dietary glucose and fructose are both efficiently assimilated by the liver but a comprehensive measurement of this process starting from their conversion to sugar phosphates, involvement of the pentose phosphate pathway (PPP), and conversion to glycogen and lipid storage products, remains incomplete. Mice were fed a chow diet supplemented with 35 g/100 mL drinking water of a 55/45 fructose/glucose mixture for 18 weeks. On the final night, the sugar mixture was enriched with either [U-13C]glucose or [U-13C]fructose, and deuterated water (2H2O) was also administered. 13C-isotopomers representing newly synthesized hepatic glucose-6-phosphate (glucose-6-P), glycerol-3-phosphate, and lipogenic acetyl-CoA were quantified by 2H and 13C NMR analysis of post-mortem liver glycogen and triglyceride. These data were applied to a metabolic model covering glucose-6-P, PPP, triose-P, and de novo lipogenesis (DNL) fluxes. The glucose supplement was converted to glucose-6-P via the direct pathway, while the fructose supplement was metabolized by the liver to gluconeogenic triose-P via fructokinase–aldolase–triokinase. Glucose-6-P from all carbohydrate sources accounted for 40–60% of lipogenic acetyl-CoA and 10–12% was oxidized by the pentose phosphate pathway (PPP). The yield of NADPH from PPP flux accounted for a minority (~30%) of the total DNL requirement. In conclusion, this approach integrates measurements of glucose-6-P, PPP, and DNL fluxes to provide a holistic and informative assessment of hepatic glucose and fructose metabolism.
Comparative Transcriptome Analysis of MeJA Responsive Enzymes Involved in Phillyrin Biosynthesis of Forsythia suspensa
Authors: Liu Xiaoran , Zhang Jiaqi , Liu Hao , Shang Huixiang , Zhao Xingli , Xu Huawei , Zhang Hongxiao , Hou Dianyun
Published: November 2022

Forsythia suspensa (Thunb.) has been widely used in traditional medicines in Asia. According to the 2020 edition of Chinese Pharmacopoeia, phillyrin is the main active ingredient in F. suspensa, which is effective in clearing heat, reducing swelling, and dispersing nodules. F. suspensa leaf is a non-toxic substance and it can be used to make a health tea. Here, we combine elicitors and transcriptomics to investigate the inducible biosynthesis of the phillyrin from the F. suspensa. After the fruits and leaves of F. suspensa were treated with different concentrations of methyl jasmonate (MeJA), the content of phillyrin in the fruits reached a peak at 200 µM MeJA for 12 h, but which was decreased in leaves. To analyze the differences in key enzyme genes involved in the phillyrin biosynthesis, we sequenced the transcriptome of F. suspensa leaves and fruits treated with 200 µM MeJA for 12 h. We hypothesized that nine genes related to coniferin synthesis including: F. suspensa UDP-glycosyltransferase (FsUGT); F. suspensa 4-coumarate coenzyme CoA ligase (Fs4CL); and F. suspensa Caffeoyl-CoA O-methyltransferase (FsCCoAOMT) etc. The qRT-PCR analysis of genes related to phillyrin biosynthesis was consistent with RNA-seq analysis. We also investigated the dynamic changes of genes in F. suspensa leaves and fruits at different time points after 200 µM MeJA treatment, which laid the foundation for further study of the molecular mechanisms regulating the biosynthesis of phillyrin.
MALDI Mass Spectrometry Imaging Reveals the Existence of an N-Acyl-homoserine Lactone Quorum Sensing System in Pseudomonas putida Biofilms
Authors: Pitchapa Rattanaburi , Dissook Sivamoke , Putri Sastia Prama , Fukusaki Eiichiro , Shimma Shuichi
Published: November 2022

Quorum sensing (QS) is generally used to describe the process involving the release and recognition of signaling molecules, such as N-acyl-homoserine lactones, by bacteria to coordinate their response to population density and biofilm development. However, detailed information on the heterogeneity of QS metabolites in biofilms remains largely unknown. Here, we describe the utilization of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to follow the production of specific metabolites, including QS metabolites, during Pseudomonas putida biofilm development. To do so, a method to grow an agar-based biofilm was first established, and MALDI-MSI was used to detect and visualize the distribution of QS metabolites in biofilms at different cultivation times. This study demonstrated that N-acyl-homoserine lactones are homogeneously produced in the early stages of P. putida biofilm formation. In contrast, the spatial distribution of quinolones and pyochelin correlated with the swarming motility of P. putida in mature biofilms. These two metabolites are involved in the production of extracellular polymeric substances and iron chelators. Our study thus contributes to establishing the specific temporal regulation and spatial distribution of N-acyl-homoserine lactone-related metabolites and quinolone and pyochelin in P. putida biofilms.
Evaluation of Three-Dimensional Surface Roughness in Microgroove Based on Bidimensional Empirical Mode Decomposition
Authors: Jiang Haiyu , Li Wenqin , Yu Zhanjiang , Yu Huadong , Xu Jinkai , Feng Lei
Published: November 2022

Micromilling is an extremely important advanced manufacturing technology in the micromanufacturing industry. Compared with the traditional milling process, micromilling has stricter requirements on the surface roughness of the workpiece, and the roughness of the microcurved surface is not easy to measure. In order to more accurately characterize the curved surface morphology of the microgrooves obtained by micromilling, this paper proposes a method to extract the reference plane of the curved surface based on the bidimensional empirical mode decomposition algorithm and characterize the three-dimensional surface roughness of the curved surface. First, we synthesize the morphologies of the microgrooves by simulated non-Gaussian rough surfaces and models of textures. Second, the bidimensional empirical mode decomposition algorithm was used to extract the reference planes of the simulated microgrooves. Third, the three-dimensional roughness parameters suitable for the curved surfaces of microgrooves were selected to establish an evaluation system. The results show that the mean squared errors of the reference planes are below 1%, so bidimensional empirical mode decomposition can effectively extract reference planes, and the evaluation system of three-dimensional surface roughness proposed in this paper reflects morphological characteristics of the curved surfaces of microgrooves more thoroughly than that of two-dimensional surface roughness parameters.
Research of Frequency Splitting Caused by Uneven Mass of Micro-Hemispherical Resonator Gyro
Authors: Song Lijun , Li Qingru , Zhao Wanliang , Zhang Tianxiang , He Xing
Published: November 2022

In practical engineering, the frequency splitting of Hemispherical Resonator Gyro (HRG) caused by uneven mass distribution seriously affects the precision of HRG. So, the inherent frequency is an important parameter of micro-Hemispherical Resonator Gyro (m-HRG). In the processing of hemispherical resonator, there are some morphological errors and internal defects in the hemispherical resonator, which affect the inherent frequency and the working mode of m-HRG, and reduce the precision and performance of m-HRG. In order to improve the precision and performance of m-HRG, the partial differential equation of the hemispherical resonator is solved, and the three-dimensional model using ANSYS software accurately reflected the actual shape is established in this paper. Then, the mode of hemispherical resonator in ideal state and uneven mass distribution state are simulated and analyzed. The frequency splitting mechanism of the hemispherical resonator is determined by calculation and demonstration, and the frequency splitting of the hemispherical resonator is suppressed by partial mass elimination. The results show that the absolute balance of energy can ensure the high-quality factor and the minimum frequency splitting of the hemispherical resonator. Therefore, during the processing of hemispherical resonator, the balance of mass should be achieved as much as possible to avoid various surface damage, internal defects and uneven mass distribution to guarantee the high-quality factor Q and minimum frequency splitting of hemispherical resonator.
A Robust Tracking Method for Multiple Moving Targets Based on Equivalent Magnetic Force
Authors: Wang Ying , Fu Qiang , Sui Yangyi
Published: November 2022

A ferromagnetic vehicle, such as a submarine, magnetized by the Earth’s magnetic field produces a magnetic anomaly field, and the tracking of moving targets can be realized through real-time analysis of magnetic data. At present, there are few tracking methods based on magnetic field vectors and their gradient tensor. In this paper, the magnetic field vector and its gradient tensor are used to calculate equivalent magnetic force. It shows the direction of the vector between the detector and the tracking targets for controlling the direction of motion of the detector and achieving the purpose of tracking. Compared with existing positioning methods, the proposed method is relatively less affected by instrument resolution and noise and maintains robustness when the velocity vectors of multiple magnetic targets change randomly.
A Convolutional Dynamic-Jerk-Planning Algorithm for Impedance Control of Variable-Stiffness Cable-Driven Manipulators
Authors: Zhang Luyang , Jia Lihui , Yang Panpan , Li Zixuan , Zhang Yuhuan , Cheng Xiang , Mu Zonggao
Published: November 2022

Cable-driven manipulators, characterized by slender arms, dexterous motion, and controllable stiffness, have great prospects for application to capture on-orbit satellites. However, it is difficult to achieve effective motion planning and stiffness control of cable-driven manipulators because of the coupled relationships between cable lengths, joint angles, and reaction forces. Therefore, a convolutional dynamic-jerk-planning algorithm is devised for impedance control of variable-stiffness cable-driven manipulators. First, a variable-stiffness cable-driven manipulator with universal modules and rotary quick-change modules is designed to overcome difficulties related to disassembly, installation, and maintenance. Second, a convolutional dynamic-jerk-planning algorithm is devised to overcome the discontinuity and shock problems of the manipulator’s velocity during intermittent control processes. The algorithm can also make acceleration smooth by setting jerk dynamically, reducing acceleration shock and ensuring the stable movement of the cable-driven manipulator. Third, the stiffness of the cable-driven manipulator is further optimized by compensating for the position and velocity of drive cables by employing position-based impedance control. Finally, the prototype of the variable-stiffness cable-driven manipulator is developed and tested. The convolutional dynamic-jerk-planning algorithm is used to plan the desired velocity curves for velocity control experiments of the cable-driven manipulator. The results verify that the algorithm can improve the acceleration smoothness, thereby making movement smooth and reducing vibrations. Furthermore, stiffness control experiments verify that the cable-driven manipulator has ideal variable stiffness capabilities.
Four-Port Dual-Band Multiple-Input Multiple-Output Dielectric Resonator Antenna for Sub-6 GHz 5G Communication Applications
Authors: Patel Upesh , Upadhyaya Trushit
Published: November 2022

A four-port dielectric resonator (DR)-based multiple-input multiple-output (MIMO) antenna is presented for sub-6 GHz MIMO communication. The dielectric resonator was fed through aperture feeding to achieve dual-band resonance. The DRA has the operating modes of TE01δ and TE10δ at 3.3 GHz and 3.9 GHz, respectively. The engineered antenna has port isolation of higher than 20 dB at the target frequencies without the employment of an extra isolation mechanism. Full-wave high-frequency simulation software was employed for the simulation computation. The antenna has a peak gain of 5.8 dBi and 6.2 dBi, and an efficiency of 88.6% and 90.2% at 3.3 GHz and 3.9 GHz, respectively. The proposed resonator has good MIMO diversity parameters. The optimal envelope correlation coefficient (ECC) is 0.01, channel capacity loss (CCL) is 0.1 bits/sec/Hz, and the total active reflection coefficient (TARC) is −22.46. The DRA elements are aligned orthogonally with adequate displacement for achieving polarization diversity and spatial diversity. The antenna delivers its applications in Sub-6 GHz 5G and WiMAX communications.
Sawing Force Prediction Model and Experimental Study on Vibration-Assisted Diamond Wire Sawing
Authors: Zhang Chenpu , Dong Zhikui , Zhao Yanheng , Liu Ziliang , Wu Shang , Yang Jiahao
Published: November 2022

Diamond wire sawing is the main machining technology for slicing various brittle materials, such as crystalline silicon, SiC, and NdFeB. Due to their high hardness and high brittleness, as well as the ease with which the surfaces of machined materials are damaged, it is difficult to further improve the sawing efficiency and the surface quality based on research conducted on the original machining method. In this paper, a vibration-assisted diamond wire sawing method is proposed. We analyzed the impact of load on the ingot, motion trajectory, and sawing depth of the abrasive particles, and a macroscopic sawing force prediction model for the vibration-assisted sawing method was established and verified via experiments. Based on the single-wire-sawing experiment and prediction model, the influences of the vibration parameters and sawing parameters on the sawing force were determined. The influences of vibration assistance on the surface quality, including the roughness profile, waviness profile, thickness profile, Ra, and Rz, were explored through single-wire-sawing experiments, and the influences of vibration assistance on the geometric parameters of slices, such as the total thickness variation (TTV) and warp, were explored through multi-wire-sawing experiments. It was found that vibration-assisted sawing can reduce sawing force and improve surface quality.
Characterization of a Dual Nonlinear Helmholtz Resonator
Authors: Al-Turk Maher O. , Ali Sajid , Hawwa Muhammad A.
Published: November 2022

Resonant elements can generate small amounts of energy that make them pertinent for feeding miniaturized accelerometers with the energy needed. Suitable oscillator candidates are Helmholtz resonators, which have been, for a long time, analyzed and designed within the context of linear vibration. This study focuses on extracting nonlinear characteristics of a dual Helmholtz resonator (HR), with a neck-cavity–neck-cavity configuration, mounted on an acoustic waveguide with harmonically oscillating pressure. The mathematical model used for describing the resonator embraces inherent nonlinear air stiffness and the damping nonlinearity of hydrodynamic origin. Numerical solutions for the resonator’s nonlinear oscillations are obtained. Bifurcation diagrams are produced, indicating that the dual HR behaves in a deterministic fashion within the engineering practical limits. Phase portraits are drawn for the system, showing a quasi-periodic motion. Frequency response curves (FRC) are found to shift to the left at the lower resonant frequency indicating a softening behavior. FRC keep generally symmetric curves at the higher resonant frequency indicating a mostly linear behavior.
Pheromone Activity after Stimulation with Ampicillin in a Plasmid-Free Enterococcus faecalis Strain
Authors: Arellano-Galindo José , Zavala-Vega Sergio , Vázquez-Larios Rosario , Ochoa Sara A. , Cruz-Córdova Ariadnna , Sierra-Santoyo Adolfo , López-González Lourdes , Hernández-Castro Rigoberto , Giono-Cerezo Silvia , Xicohtencatl-Cortes Juan
Published: November 2022

Enterococci exhibit clumping under the selective pressure of antibiotics. The aim of this study was to analyze the effect of supernatants from a plasmid-free clone (C29) of Enterococcus faecalis subjected to 0.25×, 0.5×, and 0.75× of the minimal inhibitory concentration (MIC) of ampicillin on the expression of an aggregation substance (AS) by a donor plasmid clone (1390R). A clumping assay was performed. The relative expression of prgB (gene that encodes AS) was determined and semiquantified in 1390R, and iad1 expression was determined and semiquantified in C29. AS expression was analyzed in the stimulated 1390R cells by confocal microscopy, flow cytometry, and ELISA. Adherence was also measured. Maximal clumping was observed with the pheromone medium 0.25×. Only the 1390R strain stimulated with the C29 supernatant without ampicillin and with 0.25× was able to express prgB. No expression of prgB was observed at 0.5× and 0.75×. The difference in relative expression (RE) of 1390R without ampicillin and with 0.25× was 0.5-fold. AS expression in 1390R showed the greatest increase upon stimulation with 0.25×. When 1390R was stimulated with 0.5× and 0.75×, AS expression was also observed but was significantly lower. Ampicillin stimulated C29 switch-off pheromone expression in recipient cells, which in turn switched off AS expression in donor cells. We observed that although prgB was switched off after 0.5× stimulation in C29, the supernatants induced expression in certain 1390R strains. In conclusion, ampicillin was able to modulate pheromone expression in free plasmid clones which, in turn, modulated AS expression in plasmid donor cells. The fact that PrgB gene expression was switched off after the ampicillin stimulus at 0.5× MIC, whereas AS proteins were present on the surface of the bacteria, suggested that a mechanism of rescue associated with mechanism pheromone sensing may be involved.
Improvement of the Nutraceutical Profile of Brewer’s Spent Grain after Treatment with Trametes versicolor
Authors: Zeko-Pivač Anđela , Bošnjaković Anja , Planinić Mirela , Parlov Vuković Jelena , Novak Predrag , Jednačak Tomislav , Tišma Marina
Published: November 2022

Brewer’s spent grain (BSG) is an important secondary raw material that provides a readily available natural source of nutraceuticals. It finds its largest application as animal feed and part of the human diet, while the future perspective predicts an application in the production of value-added products. In order to investigate a sustainable BSG treatment method, two BSG samples (BSG1 and BSG2) were evaluated as substrates for the production of hydrolytic (xylanase, β-glucosidase and cellulase) and lignolytic enzymes (laccase, manganese peroxidase and lignin peroxidase) by solid-state fermentation (SSF) with Trametes versicolor while improving BSG nutritional value. The biological treatment was successful for the production of all hydrolytic enzymes and laccase and manganese peroxidase, while it was unsuccessful for the production of lignin peroxidase. Because the two BSGs were chemically different, the Trametes versicolor enzymes were synthesized at different fermentation times and had different activities. Consequently, the chemical composition of the two BSG samples at the end of fermentation was also different. The biological treatment had a positive effect on the increase in protein content, ash content, polyphenolic compounds, and sugars in BSG1. In BSG2, there was a decrease in the content of reducing sugars. Cellulose, hemicellulose, and lignin were degraded in BSG1, whereas only cellulose was degraded in BSG2, and the content of hemicellulose and lignin increased. The fat content decreased in both samples. The safety-related correctness analysis showed that the biologically treated sample did not contain any harmful components and was therefore safe for use in nutritionally enriched animal feed.
Protective Effect of [Cu(NN1)2](ClO4) Complex in Rainbow Trout Challenged against Flavobacterium psychrophilum
Authors: Aldabaldetrecu Maialen , Parra Mick , Soto-Aguilera Sarita , Arce Pablo , Quiroz Amaya Paz de la Vega , Segura Rodrigo , Tello Mario , Guerrero Juan , Modak Brenda
Published: November 2022

Previously, we reported an in vitro evaluation regarding antibacterial effects against F. psychrophilum by a new Cu (I) complex, [Cu(NN1)2](ClO4). This study presents the results of an in vivo evaluation of [Cu(NN1)2](ClO4) added as a dietary supplement against F. psychrophilum in rainbow trout. The results showed that the administration of [Cu(NN1)2](ClO4) at 29 and 58 µg/g of fish for 15 days does not affect the growth of rainbow trout. On the other hand, the amount of copper present in the liver, intestine, and muscle of rainbow trout was determined. The results showed that the amount of copper in the liver, when compared between treated fish and control fish, does not change. While, in the intestine, an increase in the fish fed at 58 µg/g of fish was observed. In muscle, a slight decrease at 29 µg/g was obtained. Additionally, copper concentrations in the pond water after 15 days of feeding with the [Cu(NN1)2](ClO4) complex showed the highest levels of copper. Finally, the effect of the administration of [Cu(NN1)2](ClO4) for 15 days at 58 µg/g of fish was evaluated against F. psychrophilum, where a 75% survival was obtained during 20 days of challenge.
Avian Oropharyngeal Trichomonosis: Treatment, Failures and Alternatives, a Systematic Review
Authors: Gómez-Muñoz María Teresa , Gómez-Molinero Miguel Ángel , González Fernando , Azami-Conesa Iris , Bailén María , García Piqueras Marina , Sansano-Maestre Jose
Published: November 2022

Oropharyngeal avian trichomonosis is a potentially lethal parasitic disease that affects several avian orders. This review is focused on the disease treatments since prophylactic treatment is prohibited in most countries and resistant strains are circulating. A systematic review following the PRISMA procedure was conducted and included 60 articles. Successful and non-toxic treatments of avian oropharyngeal trichomonosis started with enheptin, a drug replaced by dimetridazole, metronidazole, ornidazole, carnidazole and ronidazole. Administration in drinking water was the most employed and recommended method, although hierarchy of the avian flocks and palatability of the medicated water can interfere with the treatments. Besides pigeons, treatments with nitroimidazoles were reported in budgerigars, canaries, finches, bald eagles, a cinereous vulture and several falcon species, but resistant strains were reported mainly in domestic pigeons and budgerigars. Novel treatments include new delivery systems proved with traditional drugs and some plant extracts and its main components. Ethanolic extracts from ginger, curry leaf tree and Dennettia tripetala, alkaloid extracts of Peganum harmala and essential oils of Pelargonium roseum and some Lamiaceae were highly active. Pure active compounds from the above extracts displayed good anti-trichomonal activity, although most studies lack a cytotoxicity or in vivo test.
First Report and Comparative Genomic Analysis of Mycoplasma capricolum subsp. capricolum HN-B in Hainan Island, China
Authors: Zhang Zhenxing , He Meirong , Jiang Junming , Li Xubo , Li Haoyang , Zhang Wencan , Chen Si , Du Li , Man Churiga , Chen Qiaoling , Gao Hongyan , Wang Fengyang
Published: November 2022

Mycoplasma capricolum subsp. Capricolum (Mcc) is an important member of the Mycoplasma mycoides cluster (Mm cluster) and causes caprine contagious agalactia. Mcc can infect goats of all age groups, especially pregnant ewes and kids. It can cause the abortion in pregnant ewes and the death of goat kids, leading to enormous losses in the goat breeding industry. To date, the prevalence of epidemic Mcc strains on Hainan Island, China, remains unclear. This study aimed to isolate and identify Mcc strains endemic to Hainan Island, China. Genome sequencing and comparative genomic analysis were performed to reveal the molecular characteristics and evolutionary relationships of the isolated strain. Mcc HN-B was isolated and identified in Hainan Island, China. The Mcc HN-B genome consists of a 1,117,925 bp circular chromosome with a 23.79% G + C content. It contains 912 encoding genes, 3 gene islands, and 14 potential virulence genes. The core genome with the features of the Mm cluster and the specific genes of Mcc HN-B were identified by comparative genomic analysis. These results revealed the evolutionary relationship between Mcc HN-B and other members of the Mm cluster. Our findings provide a reference for further studies on the pathogenic mechanism and local vaccine development of Mcc.
Salmonella enterica Outbreaks Linked to the Consumption of Tahini and Tahini-Based Products
Authors: Coulombe Geneviève , Tamber Sandeep
Published: November 2022

Salmonella is a leading cause of bacterial foodborne illness in the world. Although typically associated with foods of animal origin, low-moisture foods, such as tahini, are quickly gaining recognition as an important vehicle of Salmonella exposure. This review offers the Canadian perspective on the issue of Salmonella in tahini and tahini-based products. A summary of several recent food product recalls and foodborne outbreaks related to the presence of Salmonella in tahini and tahini-based products such as halva are presented. The properties of the food vehicles, their production practices, and potential routes of contamination are discussed. Particular focus is placed on the ecology of Salmonella in the tahini production continuum, including its survival characteristics and response to intervention technologies.
Applications of MALDI-TOF Mass Spectrometry to the Identification of Parasites and Arthropod Vectors of Human Diseases
Authors: Sánchez-Juanes Fernando , Calvo Sánchez Noelia , Belhassen García Moncef , Vieira Lista Carmen , Román Raul Manzano , Álamo Sanz Rufino , Muro Álvarez Antonio , Muñoz Bellido Juan Luis
Published: November 2022

Arthropod vectors and parasites are identified morphologically or, more recently, by molecular methods. Both methods are time consuming and require expertise and, in the case of molecular methods, specific devices. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification of bacteria has meant a major change in clinical microbiology laboratories because of its simplicity, speed and specificity, and its capacity to identify microorganisms, in some cases, directly from the sample (urine cultures, blood cultures). Recently, MALDI-TOF MS has been shown as useful for the identification of some parasites. On the other hand, the identification of vector arthropods and the control of their populations is essential for the control of diseases transmitted by arthropods, and in this aspect, it is crucial to have fast, simple and reliable methods for their identification. Ticks are blood-sucking arthropods with a worldwide distribution, that behave as efficient vectors of a wide group of human and animal pathogens, including bacteria, protozoa, viruses, and even helminths. They are capable of parasitizing numerous species of mammals, birds and reptiles. They constitute the second group of vectors of human diseases, after mosquitoes. MALDI-TOF MS has been shown as useful for the identification of different tick species, such as Ixodes, Rhipicephalus and Amblyomma. Some studies even suggest the possibility of being able to determine, through MALDI-TOF MS, if the arthropod is a carrier of certain microorganisms. Regarding mosquitoes, the main group of vector arthropods, the possibility of using MALDI-TOF MS for the identification of different species of Aedes and Anopheles has also been demonstrated. In this review, we address the possibilities of this technology for the identification of parasites and arthropod vectors, its characteristics, advantages and possible limitations.
Distribution Patterns of Antibiotic Resistance Genes and Their Bacterial Hosts in a Manure Lagoon of a Large-Scale Swine Finishing Facility
Authors: Begmatov Shahjahon , Beletsky Alexey V. , Gruzdev Eugeny V. , Mardanov Andrey V. , Glukhova Lubov B. , Karnachuk Olga V. , Ravin Nikolai V.
Published: November 2022

The spread of antibiotic resistance genes (ARGs) that are present in livestock manures, which are discharged into the environment, is a severe threat to human and animal health. Here, we used 16S rRNA gene profiling and metagenomic analysis to characterize microbial community composition and antibiotic resistance in a manure storage lagoon from a large-scale swine finishing facility. Manure samples were collected at intervals of two years. Both the prokaryotic community and the resistome were dominated by the Firmicutes, Proteobacteria and Bacteroidota. Metagenomic analysis of two samples revealed 726 and 641 ARGs classified into 59 and 46 AMR gene families. Besides multidrug efflux pumps, the predominating ARGs potentially encoded resistance to tetracyclines, macrolide–lincosamide–streptogramin, aminoglycosides, peptide antibiotics, rifamycin, chloramphenicol, and beta-lactams. Genes from all predominant AMR gene families were found in both samples indicating overall long-term stability of the resistome. Antibiotic efflux pumps were the primary type of ARGs in the Proteobacteria, while antibiotic target alteration or protection was the main mechanism of resistance in the Firmicutes, Actinobacteriota and Bacteroidota. Metagenome-assembled genomes (MAG) of four multidrug-resistant strains were assembled. The first MAG, assigned to Escherichia flexneri, contained 46 ARGs, including multidrug efflux pumps, modified porins, beta-lactamases, and genes conferring resistance to peptide antibiotics. The second MAG, assigned to the family Alcaligenaceae, contained 18 ARGs encoding resistance to macrolide–lincosamide–streptogramin, tetracyclines, aminoglycosides and diaminopyrimidins. Two other MAGs representing the genera Atopostipes and Prevotella, contained four and seven ARGs, respectively. All these MAGs represented minor community members and accounted for less than 0.3% of the whole metagenome. Overall, a few lineages originated from the gut but relatively rare in the manure storage lagoon, are the main source of ARGs and some of them carry multiple resistance determinants.