bluuebunny/crossref_metadata_2025 huggingface dataset:
Dual Variational Formulations for a Large Class of Non-Convex Models in the Calculus of Variations
Authors: Botelho Fabio Silva
Published: December 2022

This article develops dual variational formulations for a large class of models in variational optimization. The results are established through basic tools of functional analysis, convex analysis and duality theory. The main duality principle is developed as an application to a Ginzburg–Landau-type system in superconductivity in the absence of a magnetic field. In the first section, we develop new general dual convex variational formulations, more specifically, dual formulations with a large region of convexity around the critical points, which are suitable for the non-convex optimization for a large class of models in physics and engineering. Finally, in the last section, we present some numerical results concerning the generalized method of lines applied to a Ginzburg–Landau-type equation.
The ∗-Ricci Operator on Hopf Real Hypersurfaces in the Complex Quadric
Authors: Ma Rongsheng , Pei Donghe
Published: December 2022

We study the ∗-Ricci operator on Hopf real hypersurfaces in the complex quadric. We prove that for Hopf real hypersurfaces in the complex quadric, the ∗-Ricci tensor is symmetric if and only if the unit normal vector field is singular. In the following, we obtain that if the ∗-Ricci tensor of Hopf real hypersurfaces in the complex quadric is symmetric, then the ∗-Ricci operator is both Reeb-flow-invariant and Reeb-parallel. As the correspondence to the semi-symmetric Ricci tensor, we give a classification of real hypersurfaces in the complex quadric with the semi-symmetric ∗-Ricci tensor.
Optimal Operation of PV Sources in DC Grids for Improving Technical, Economical, and Environmental Conditions by Using Vortex Search Algorithm and a Matrix Hourly Power Flow
Authors: Grisales-Noreña Luis Fernando , Rosales-Muñoz Andrés Alfonso , Cortés-Caicedo Brandon , Montoya Oscar Danilo , Andrade Fabio
Published: December 2022

This document presents a master–slave methodology for solving the problem of optimal operation of photovoltaic (PV) distributed generators (DGs) in direct current (DC) networks. This problem was modeled using a nonlinear programming model (NLP) that considers the minimization of three different objective functions in a daily operation of the system. The first one corresponds to the minimization of the total operational cost of the system, including the energy purchasing cost to the conventional generators and maintenance costs of the PV sources; the second objective function corresponds to the reduction of the energy losses associated with the transport of energy in the network, and the third objective function is related to the minimization of the total emissions of CO2 by the conventional generators installed on the DC grid. The minimization of these objective functions is achieved by using a master–slave optimization approach through the application of the Vortex Search algorithm combined with a matrix hourly power flow. To evaluate the effectiveness and robustness of the proposed approach, two test scenarios were used, which correspond to a grid-connected and a standalone network located in two different regions of Colombia. The grid-connected system emulates the behavior of the solar resource and power demand of the city of Medellín-Antioquia, and the standalone network corresponds to an adaptation of the generation and demand curves for the municipality of Capurganá-Choco. A numerical comparison was performed with four optimization methodologies reported in the literature: particle swarm optimization, multiverse optimizer, crow search algorithm, and salp swarm algorithm. The results obtained demonstrate that the proposed optimization approach achieved excellent solutions in terms of response quality, repeatability, and processing times.
A Survey on Big Data Technologies and Their Applications to the Metaverse: Past, Current and Future
Authors: Zhang Haolan , Lee Sanghyuk , Lu Yifan , Yu Xin , Lu Huanda
Published: December 2022

The development of big data technologies, which have been applied extensively in various areas, has become one of the key factors affecting modern society, especially in the virtual reality environment. This paper provides a comprehensive survey of the recent developments in big data technologies, and their applications to virtual reality worlds, such as the Metaverse, virtual humans, and digital twins. The purpose of this survey was to explore several cutting-edge big data and virtual human modelling technologies, and to raise the issue of future trends in big data technologies and the Metaverse. This survey investigated the applications of big data technologies in several key areas—including e-health, transportation, and business and finance—and the main technologies adopted in the fast-growing virtual world sector, i.e., the Metaverse.
Acoustic Sounding of Hydraulic Fractures in a Low-Permeability Reservoir
Authors: Shagapov Vladislav Sh. , Galiakbarova Emiliya , Khakimova Zulfiya
Published: December 2022

Theoretical models indicate the possibility of diagnosing the presence and the conductivity of the hydraulic fractures in reservoirs of the permeability of order milli Darcy by means of an acoustic TV set, which is a cylindrical probe of the length of several meters with a generator of impulse signals and pressure sensors. It is suggested to generate an impulse signal in a fluid, filling the gap between the probe body and the outer wall of the borehole. It is supposed that the impulse signal is generated in a fluid located in the gap between the probe body and an outer wall of the borehole. The signal evolution recorded by means of the pressure sensors as a damping of its amplitude and the appearance of the reflected burst of pressure allow one to estimate the presence and the conductivity of the fractures in the bottomhole zone. We consider fractures, which are radial or longitudinal to an open part of the borehole. The length of the impulse signal is less than the length of the probe, but exceeds the width of the gap between the probe body and the outer wall of the borehole. We take into consideration the damping of the impulse signal due to the viscosity effects in a boundary layer near the borehole walls. The width of a fracture is much less than the wavelength, and this is why the radial fracture is admitted by the reflecting surface. We provide the results of the dispersion analysis and numerical experiments on the influence of the filtration characteristics of the fractures, the width of the gap and the type of fluid on the evolution of the impulse signals in the channel.
Nitrogen Sources Affect the Long-Chain Polyunsaturated Fatty Acids Content in Thraustochytrium sp. RT2316-16
Authors: Valdebenito Diego , Urrutia Sebastián , Leyton Allison , Chisti Yusuf , Asenjo Juan A. , Shene Carolina
Published: December 2022

The psychrophilic marine microorganism Thraustochytrium sp. RT2316-16 can produce carotenoids as well as lipids containing the omega-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid and docosahexaenoic acid. This work reports on the effects of the composition of the culture medium, including certain amino acids, on growth and lipid synthesis by RT2316-16. Compared with the culture on glutamate, the use of lysine, alanine, or serine, increased the content of the omega-3 PUFA in total lipids. In the media that contained yeast extract, glutamate, and glucose, lipid accumulation occurred when organic ammonium was exhausted earlier than glucose. In contrast, lipid mobilization was promoted if glucose was exhausted while organic ammonium (supplied by yeast extract and glutamate) remained in the medium. The total content of carotenoids in the lipid-free biomass decreased during the first 12 to 24 h of culture, simultaneously with a decrease in the total lipid content of the biomass. The experimental data suggested a possible interrelationship between the metabolism of carotenoids and lipids. A high content of omega-3 PUFA in the total lipids could be obtained by growing the thraustochytrid in a medium with a low glucose concentration (6 g L−1) and a high concentration of organic nitrogen (yeast extract 12 g L−1; glutamate 1.06 g L−1), after glucose was exhausted. These observations may guide the development of a strategy to enhance omega-3 PUFA in the biomass.
The ESCRT-III Protein Chmp1 Regulates Lipid Storage in the Drosophila Fat Body
Authors: Fruin Austin M. , Leon Kelly E. , DiAngelo Justin R.
Published: December 2022

Defects in how excess nutrients are stored as triglycerides can result in several diseases including obesity, heart disease, and diabetes. Understanding the genes responsible for normal lipid homeostasis will help understand the pathogenesis of these diseases. RNAi screens performed in Drosophila cells identified genes involved in vesicle formation and protein sorting as important for the formation of lipid droplets; however, all of the vesicular trafficking proteins that regulate lipid storage are unknown. Here, we characterize the function of the Drosophila Charged multivesicular protein 1 (Chmp1) gene in regulating fat storage. Chmp1 is a member of the ESCRT-III complex that targets membrane localized signaling receptors to intralumenal vesicles in the multivesicular body of the endosome and then ultimately to the lysosome for degradation. When Chmp1 levels are decreased specifically in the fly fat body, triglyceride accumulates while fat-body-specific Chmp1 overexpression decreases triglycerides. Chmp1 controls triglyceride storage by regulating the number and size of fat body cells produced and not by altering food consumption or lipid metabolic enzyme gene expression. Together, these data uncover a novel function for Chmp1 in controlling lipid storage in Drosophila and supports the role of the endomembrane system in regulating metabolic homeostasis.
Application of an Integrated System of Thermal Pressure Hydrolysis/Membrane Techniques to Recover Chromium from Tannery Waste for Reuse in Hide Tanning Processes
Authors: Kowalik-Klimczak Anna , Życki Maciej , Łożyńska Monika , Schadewell Christian , Fiehn Thomas , Woźniak Bogusław , Flisek Monika
Published: December 2022

This paper presents the results of research on a new method of chromium recovery from solid waste generated during the tanning of raw hides. In the first stage, the shredded mixture of useless leather scraps is decomposed through thermal pressure hydrolysis (TPH) in nitric acid in appropriate process conditions. Then, the liquid product of this process (hydrolysate) is fractionated using membrane separation techniques. The microfiltration (MF) process enables the initial purification of the hydrolysate by concentrating the organic matter. On the other hand, the nanofiltration (NF) process enables a three-fold concentration of total chromium in the pre-purified hydrolysate. The total chromium concentrate prepared in the above manner was successfully used in the model tanning processes. These processes were carried out on pickled bovine hides, using a mixture of a commercial chromium tanning agent and chromium concentrate after nanofiltration. The reference sample was bovine hide traditionally tanned with a commercial chromium tanning agent. Based on the results of the physical and chemical analyses, it was found that the properties of hides tanned using chromium recovered from waste are similar to those of hides tanned traditionally using a commercially available chromium tanning agent. The industrial implementation of the developed tannery waste valorisation technology would enable transition from a linear economy to circular economy.
Mitigating of Thin-Film Composite PTMSP Membrane Aging by Introduction of Porous Rigid and Soft Branched Polymeric Additives
Authors: Bakhtin Danila S. , Malakhov Alexander O. , Volkov Alexey V. , Kulikov Leonid A. , Petrova Inna V. , Borisov Ilya L. , Bazhenov Stepan D.
Published: December 2022

This work was focused on the mitigation of physical aging in thin-film composite (TFC) membranes (selective layer ~1 μm) based on polymer intrinsic microporosity (PTMSP) by the introduction of both soft, branched polyethyleneimine (PEI), and rigid, porous aromatic framework PAF-11, polymer additives. Self-standing mixed-matrix membranes of thicknesses in the range of 20–30 μm were also prepared with the same polymer and fillers. Based on 450 days of monitoring, it was observed that the neat PTMSP composite membrane underwent a severe decline of its gas transport properties, and the resultant CO2 permeance was 14% (5.2 m3 (STP)/(m2·h·bar)) from the initial value measured for the freshly cast sample (75 m3 (STP)/(m2·h·bar)). The introduction of branched polyethyleneimine followed by its cross-linking allowed to us to improve the TFC performance maintaining CO2 permeance at the level of 30% comparing with day zero. However, the best results were achieved by the combination of porous, rigid and soft, branched polymeric additives that enabled us to preserve the transport characteristics of TFC membrane as 43% (47 m3 (STP)/(m2·h·bar) after 450 days) from its initial values (110 m3 (STP)/(m2·h·bar)). Experimental data were fitted using the Kohlrausch–Williams–Watts function, and the limiting (equilibrium) values of the CO2 and N2 permeances of the TFC membranes were estimated. The limit value of CO2 permeance for neat PTMSP TFC membrane was found to be 5.2 m3 (STP)/(m2·h·bar), while the value of 34 m3(STP)/(m2·h·bar) or 12,600 GPU was achieved for TFC membrane containing 4 wt% cross-linked PEI, and 30 wt% PAF-11. Based on the N2 adsorption isotherms data, it was calculated that the reduction of the free volume was 1.5–3 times higher in neat PTMSP compared to the modified one. Bearing in mind the pronounced mitigation of physical aging by the introduction of both types of fillers, the developed high-performance membranes have great potential as support for the coating of an ultrathin, selective layer for gas separation.
Experimental and Numerical Study of Pd/Ta and PdCu/Ta Composites for Thermocatalytic Hydrogen Permeation
Authors: Ryu Seungbo , Badakhsh Arash , Oh Je Gyu , Ham Hyung Chul , Sohn Hyuntae , Yoon Sung Pil , Choi Sun Hee
Published: December 2022

The development of stable and durable hydrogen (H2) separation technology is essential for the effective use of H2 energy. Thus, the use of H2 permeable membranes, made of palladium (Pd), has been extensively studied in the literature. However, Pd has considerable constraints in large-scale applications due to disadvantages such as very high cost and H2 embrittlement. To address these shortcomings, copper (Cu) and Pd were deposited on Ta to fabricate a composite H2 permeable membrane. To this end, first, Pd was deposited on a tantalum (Ta) support disk, yielding 7.4 × 10−8 molH2 m−1 s−1 Pa−0.5 of permeability. Second, a Cu–Pd alloy on a Ta support was synthesized via stepwise electroless plating and plasma sputtering to improve the durability of the membrane. The use of Cu is cost-effective compared with Pd, and the appropriate composition of the PdCu alloy is advantageous for long-term H2 permeation. Despite the lower H2 permeation of the PdCu/Ta membrane (than the Pd/Ta membrane), about two-fold temporal stability is achieved using the PdCu/Ta composite. The degradation process of the Ta support-based H2 permeable membrane is examined by SEM. Moreover, thermocatalytic H2 dissociation mechanisms on Pd and PdCu were investigated and are discussed numerically via a density functional theory study.
A Mechanism of Double-Membrane Vesicle Formation from Liquid-Ordered/Liquid-Disordered Phase Separated Spherical Membrane
Authors: Kondrashov Oleg V. , Akimov Sergey A.
Published: December 2022

Genome replication of coronaviruses takes place in specific cellular compartments, in so-called double-membrane vesicles (DMVs), formed from the endoplasmic reticulum (ER). An intensive production of DMVs is induced by non-structural viral proteins. Here, we proposed a possible mechanism of the DMV formation from ER-derived spherical vesicles where liquid-ordered and liquid-disordered lipid phases coexist. These vesicles are supposed to divide into two homogeneous liquid-ordered and liquid-disordered vesicles. The formation of two spherical vesicles constituting DMV requires a mechanical work to be performed. We considered the excess energy of the boundary between the coexisting lipid phases as the main driving force behind the division of the initial vesicle. Explicitly accounting for the energy of elastic deformations and the interphase boundary energy, we analyzed a range of physical parameters where the DMV formation is possible. We concluded that this process can principally take place in a very narrow range of system parameters. The most probable diameter of DMVs formed according to the proposed mechanism appeared to be approximately 220 nm, in an agreement with the average diameter of DMVs observed in vivo. Our consideration predicts the DMV size to be strongly limited from above. The developed analysis can be utilized for the production of DMVs in model systems.
Poly(ethylene oxide)-Based Copolymer-IL Composite Membranes for CO2 Separation
Authors: Vroulias Dionysios , Staurianou Eirini , Ioannides Theophilos , Deimede Valadoula
Published: December 2022

Poly(ethylene oxide) (PEO)-based copolymers are at the forefront of advanced membrane materials for selective CO2 separation. In this work, free-standing composite membranes were prepared by blending imidazolium-based ionic liquids (ILs) having different structural characteristics with a PEO-based copolymer previously developed by our group, targeting CO2 permeability improvement and effective CO2/gas separation. The effect of IL loading (30 and 40 wt%), alkyl chain length of the imidazolium cation (ethyl- and hexyl- chain) and the nature of the anion (TFSI-, C(CN)3-) on physicochemical and gas transport properties were studied. Among all composite membranes, PEO-based copolymer with 40 wt% IL3-[HMIM][TFSI] containing the longer alkyl chain of the cation and TFSI- as the anion exhibited the highest CO2 permeability of 46.1 Barrer and ideal CO2/H2 and CO2/CH4 selectivities of 5.6 and 39.0, respectively, at 30 °C. In addition, almost all composite membranes surpassed the upper bound limit for CO2/H2 separation. The above membrane showed the highest water vapor permeability value of 50,000 Barrer under both wet and dry conditions and a corresponding H2O/CO2 ideal selectivity value of 1080; values that are comparable with those reported for other highly water-selective PEO-based polymers. These results suggest the potential application of this membrane in hydrogen purification and dehydration of CO2 gas streams.
Performance and Mechanism of Nanoporous Ni@NiO Composites for RhB Ultrahigh Electro-Catalytic Degradation
Authors: Wang Xiaoyu , Pan Fengda , Sun Xinhao , Li Yongyan , Zhou Jun , Wang Zhifeng , Qin Chunling
Published: December 2022

Today, the development of new self-supporting electrode materials with high porosity and excellent degradation properties is of great importance for the removal of dye pollutants. Herein, this work synthesized nanoporous nickel@nickel oxide (np-Ni@NiO) electrode containing an amorphous alloy in the middle interlayer. The nanoporous structure endowed the electrode with more active sites and facilitated the ion/electron transport. The electrochemical active surface area was about 185.5 cm2. The electrochemical degradation of rhodamine B (RhB) using a np-Ni@NiO electrode was systematically investigated. The effects of technology paraments (NaCl concentration, the applied potential and pH) on electro-catalytic degradation were explored. An RhB removal rate of 99.68% was achieved in 30 s at optimized conditions, which was attributed to the unique bicontinuous ligament/pore structure and more active sites on the surface, as well as lower charge transfer resistance. In addition, the degradation mechanism of RhB in electrochemical oxidation was proposed, according to active species capture tests and EPR measurements.
Effects of Al-Mg on the Microstructure and Phase Distribution of Zn-Al-Mg Coatings
Authors: Zhang Ziyue , Zhang Jie , Zhao Xingyuan , Cheng Xuequn , Jiang Sheming , Zhang Qifu
Published: December 2022

In this work, the composition of the zinc–aluminum–magnesium alloy coating was designed to have a fixed aluminum–magnesium ratio of 1:1, while the content of aluminum and magnesium elements increases gradually within the range of 1–2 wt.%. The micro-morphology of the coating with different compositions was observed by a scanning electron microscope (SEM). Combined with the surface distribution results of energy dispersive spectrometer (EDS) analysis elements and the phase analysis results of diffraction of X-rays (XRD), the phase distribution of the coating is understood. The statistical calculation of the phase distribution was carried out after staining the SEM image by ImageJ, This is consistent with the solidification simulation results of the thermodynamic simulation software (PADAT). The influence of magnesium and aluminum elements on the microscopic morphology and phase distribution of the zinc–aluminum–magnesium (ZnAlMg) coating was studied, and the mechanism of action was analyzed. The results show that the volume ratio of binary eutectic phase (Zn/MgZn2) and ternary eutectic phase (Zn/Al/MgZn2) in the coating tends to increase as the contents of the two elements elevate. The quantity of MgZn2 is the critical factor for the corrosion resistance of the coating; the more MgZn2, the better the corrosion resistance.
Experimental Investigation of the Effects of Process Parameters on the Radius of Curvature in Laser Forming Process of Cylindrical Surfaces
Authors: Safari Mehdi , Miralaa Seyed Mohammad , Alves de Sousa Ricardo
Published: December 2022

In this work, the laser forming process of cylindrical surfaces is studied experimentally. For this purpose, the effects of process parameters such as laser power, laser scanning scheme, and distance between irradiation lines on the radius of curvature of the laser-formed cylindrical surfaces are examined. The design of experiment (DOE) method based on the Box–Behnken algorithm is also employed for investigations. To produce the cylindrical surfaces from flat sheets, parallel lines are used as the irradiation scheme. The results show that by increasing the laser power, the radius of curvature for a laser-formed cylindrical surface can be decreased. Additionally, the radius of curvature of the cylindrical surface increases when the scanning speed increases. In addition, it is concluded that the radius of curvature decreases when the distance between irradiation lines increases.
Effects of Graphite Particle Content and Holding Time on the Microstructure and Mechanical Properties of the Graphite/AZ91D Composite
Authors: Gao Xin , Geng Kejian , Sun Cuicui , Zhang Suqing , Zhou Jixue , Wu Jianhua , Zhang Xinfang , Wang Xitao
Published: December 2022

The effects of Grp (graphite particles) addition and holding time on the microstructure and mechanical properties of the Grp/AZ91D composite were investigated in this work. The results indicated that the distribution of Grp in the matrix was determined by the self-stabilizing mechanism and relationships between the solidifying interface and the particles. Due to the self-stabilizing mechanism, a small amount of Grp would uniformly distribute in the melt alloy, and as the amount of Grp increased, agglomeration would occur. Accordingly, the former would be engulfed by the solidifying interface and the latter would be pushed. With an increased holding time, Grp tended to agglomerate, due to the interfacial reaction that occurred, and as a result, the solidifying interface will push it. The Grp/AZ91D composite with the addition of 1.5 wt.% Grp and a holding time of 15 min obtained grains 30.2 μm in size with a hardness of 89.07 HV, which was a decrease of 83.04% and increase of 35.06% compared to AZ91D, respectively.
Evaluation of the Laser Cleaning Efficacy of Q235 Steel Using Laser-Induced Breakdown Spectroscopy
Authors: Zaheer Ud Din Syed , Shi Chenglin , Zhang Qinduan , Wei Yubin , Zhang Wenhao
Published: December 2022

Laser cleaning is a good alternative to ablate and remove contaminants from different samples. To meet the practical demand, we present the elemental analysis of Q235 steel samples, using laser-induced breakdown spectroscopy (LIBS) to enhance the laser cleaning process. Two samples were selected and kept in water and soil for 4 and 7 days, respectively. Half of the samples were then cleaned using the laser cleaning method. The objectives were to promote the application of laser cleaning, generalize the LIBS for the laser cleaning settings, and identify the different sources of contaminations. Numerous elements were determined by analyzing the LIBS spectra, including Fe, Mn, Cu, Si, Ni, Cr, C, S, and P. After 20 excitation cycles, LIBS signals were comparatively stable and could participate in the ensuing classification modeling procedure. The contaminated samples were noticeably stronger overall than the uncontaminated samples, with the higher the concentration of a certain element, the higher the characteristic spectral intensity of LIBS. The typical spectral intensity and concentration of the two samples were found to be in good agreement.
Effect of Double-Quenching on the Hardness and Toughness of a Wear-Resistant Steel
Authors: Wang Jingliang , Qian Rongtao , Huang Song , Shang Chengjia
Published: December 2022

Martensitic/bainitic wear-resistant steels are widely used in civilian industry, where a good combination of strength and toughness is required. In the present study, a double-quenching process was applied and compared to the conventional single-quenching process. The microhardness and ductile–brittle transition temperature were measured, and the microstructure was characterized with scanning electron microscopy and electron backscatter diffraction (EBSD) technique. It was found that the double-quenching process refined the prior austenite grain size by 43% and simultaneously improved the toughness and hardness. The ductile-to-brittle transition temperature was decreased from −77 °C to −90 °C, and the hardness was increased by 8%. Based on the EBSD data, a detailed analysis of the grain boundary distribution was performed using a recently developed machine learning model. Unlike what was found in previous studies, for the studied wear-resistant steel, the refinement of the prior austenite grain did not increase the block boundary density while increasing the high-angle packet boundary density. As a result, the total density of the high-angle grain boundaries in the double-quenched specimen was not improved compared to the single-quenched specimen. Further inspection suggested that it is the prior austenite grain boundaries and high-angle packet boundaries that contribute to the hardness and toughness, and the key factors that determine their effectiveness are the high misorientation angle between the {110} slip planes and the high slip transmission factor.
Effect of Return Fines Embedding on the Sintering Behaviour of Vanadium Titanium Magnetite Concentrates
Authors: Peng Shihong , Liu Hao , Hua Huangjie , Sun Zezheng , Qin Yuelin , Meng Fei , Liu Weiqiang , Wang Guang
Published: December 2022

To improve the permeability of sinter packed bed for achieving the efficient utilization of low-grade iron bearing minerals, the effect of the returned fines embedding on productivity, yield, flame front speed (FFS) in the vanadium titanium magnetite (VTM) sintering process, tumble index (TI) of sinter, and permeability of the sinter packed bed was clarified. Results indicate that the productivity, yield, flame front speed, and tumble index of the vanadium titanium magnetite sintering process are all increased to a certain extent after embedding different sizes of returned fines, and the optimal sintering indices occur when the particle size of return fines for embedding is 3~5 mm. The optimal mass ratio of return fines for embedding was confirmed at 80%, and a continued increase in the mass ratio results in a decrease in flame front speed, yield, productivity, and tumble strength. Among the five different possible locations of embedded return fine layer, the middle-lower layer corresponds to the highest flame front speed. As the mass ratio of return fines for embedding is enhanced from 0% to 50%, the permeability of the sinter packed bed is improved at each stage of sintering.
Maternal Metabolites Indicative of Mental Health Status during Pregnancy
Authors: Laketic Katarina , Lalonde-Bester Sophie , Smyth Kim , Slater Donna M. , Tough Suzanne C. , Ishida Hiroaki , Vogel Hans J. , Giesbrecht Gerald F. , Mu Chunlong , Shearer Jane
Published: December 2022

Approximately 25% of individuals report poor mental health during their pregnancy or postpartum period, which may impact fetal neurodevelopment, birth outcomes, and maternal behaviors. In the present study, maternal serum samples were collected from pregnancies at 28–32 weeks gestation from the All Our Families (Alberta, Canada) cohort and assessed using nuclear magnetic resonance spectroscopy (1H-NMR) and inductively coupled plasma-mass spectrometry (ICP-MS). Individuals with poor mental health at 34–36 weeks gestation were age-matched with mentally healthy pregnant controls. Metabolites were examined against validated self-reported mental health questionnaires for associations with depressive symptoms (Edinburgh Perinatal Depression Scale) and anxiety symptoms (Spielberger State-Trait Anxiety Inventory). 1H-NMR metabolites were identified for depression (alanine, leucine, valine, methionine, phenylalanine, glucose, lactate, 3-hydroxybutyrate, and pyruvate) and anxiety (3-hydroxybutyrate). For ICP-MS, antimony and zinc were significant for depression and anxiety, respectively. Upon false discovery rate (FDR) correction at 10%, five 1H-NMR metabolites (alanine, leucine, lactate, glucose, and phenylalanine) for depression remained significantly increased. Although results warrant further validation, the identified metabolites may serve as a predictive tool for assessing mental health during pregnancy as earlier identification has the potential to aid intervention and management of poor mental health symptomology, thus avoiding harmful consequences to both mother and offspring.
Urinary ATP Levels Are Controlled by Nucleotidases Released from the Urothelium in a Regulated Manner
Authors: Gutierrez Cruz Alejandro , Aresta Branco Mafalda S. L. , Perrino Brian A. , Sanders Kenton M. , Mutafova-Yambolieva Violeta N.
Published: December 2022

Adenosine 5′-triphosphate (ATP) is released in the bladder lumen during filling. Urothelial ATP is presumed to regulate bladder excitability. Urinary ATP is suggested as a urinary biomarker of bladder dysfunctions since ATP is increased in the urine of patients with overactive bladder, interstitial cystitis or bladder pain syndrome. Altered urinary ATP might also be associated with voiding dysfunctions linked to disease states associated with metabolic syndrome. Extracellular ATP levels are determined by ATP release and ATP hydrolysis by membrane-bound and soluble nucleotidases (s-NTDs). It is currently unknown whether s-NTDs regulate urinary ATP. Using etheno-ATP substrate and HPLC-FLD detection techniques, we found that s-NTDs are released in the lumen of ex vivo mouse detrusor-free bladders. Capillary immunoelectrophoresis by ProteinSimple Wes determined that intraluminal solutions (ILS) collected at the end of filling contain ENTPD3 > ENPP1 > ENPP3 ≥ ENTPD2 = NT5E = ALPL/TNAP. Activation of adenylyl cyclase with forskolin increased luminal s-NTDs release whereas the AC inhibitor SQ22536 had no effect. In contrast, forskolin reduced and SQ22536 increased s-NTDs release in the lamina propria. Adenosine enhanced s-NTDs release and accelerated ATP hydrolysis in ILS and lamina propria. Therefore, there is a regulated release of s-NTDs in the bladder lumen during filling. Aberrant release or functions of urothelial s-NTDs might cause elevated urinary ATP in conditions with abnormal bladder excitability.
Glycerol and Natural Deep Eutectic Solvents Extraction for Preparation of Luteolin-Rich Jasione montana Extracts with Cosmeceutical Activity
Authors: Juszczak Aleksandra Maria , Marijan Marijan , Jakupović Lejsa , Tomczykowa Monika , Tomczyk Michał , Zovko Končić Marijana
Published: December 2022

Jasione montana is a plant from the family Campanulaceae rich in phenols with health-beneficial properties such as luteolin (LUT) derivatives. In this work, a glycerol-based ultrasound-assisted extraction method was developed and optimized for in total phenol (TP) and LUT content, as well as antiradical activity (RSA). The best conditions (glycerol content, temperature, plant material weight, and ultrasonication power) for the preparation of J. montana extracts richest in TP (OPT-TP), LUT (OPT-LUT), and having the best RSA (OPT-RSA) were determined. Furthermore, numerous natural deep eutectic solvents (NADES), containing proline, glycerol, betaine, urea, and glucose were prepared and used for the extraction of J. montana. Contents of TP, LUT, and RSA in the prepared extracts were established. Antioxidant and cosmeceutical activity of the prepared extracts was tested. The OPT-TP, OPT-LUT, and OPT-RSA, as well as the most efficient NADES-based extract, PG-50-TP, were excellent antioxidants and Fe2+ ion chelators. In addition, they were potent inhibitors of collagenase and hyaluronidase, as well as good significant anti-elastase and -lipoxygenase activity. The observed antioxidant- and enzyme-inhibiting activity of J. montana extracts prepared using environmentally friendly methods and non-toxic solvents makes them promising ingredients of cosmeceutical products.
Genetic Predisposition to Hepatocellular Carcinoma
Authors: Pascale Rosa M. , Calvisi Diego F. , Feo Francesco , Simile Maria M.
Published: December 2022

Liver preneoplastic and neoplastic lesions of the genetically susceptible F344 and resistant BN rats cluster, respectively, with human HCC with better (HCCB) and poorer prognosis (HCCP); therefore, they represent a valid model to study the molecular alterations determining the genetic predisposition to HCC and the response to therapy. The ubiquitin-mediated proteolysis of ERK-inhibitor DUSP1, which characterizes HCC progression, favors the unrestrained ERK activity. DUSP1 represents a valuable prognostic marker, and ERK, CKS1, or SKP2 are potential therapeutic targets for human HCC. In DN (dysplastic nodule) and HCC of F344 rats and human HCCP, DUSP1 downregulation and ERK1/2 overexpression sustain SKP2-CKS1 activity through FOXM1, the expression of which is associated with a susceptible phenotype. SAM-methyl-transferase reactions and SAM/SAH ratio are regulated by GNMT. In addition, GNMT binds to CYP1A, PARP1, and NFKB and PREX2 gene promoters. MYBL2 upregulation deregulates cell cycle and induces the progression of premalignant and malignant liver. During HCC progression, the MYBL2 transcription factor positively correlates with cells proliferation and microvessel density, while it is negatively correlated to apoptosis. Hierarchical supervised analysis, regarding 6132 genes common to human and rat liver, showed a gene expression pattern common to normal liver of both strains and BN nodules, and a second pattern is observed in F344 nodules and HCC of both strains. Comparative genetics studies showed that DNs of BN rats cluster with human HCCB, while F344 DNs and HCCs cluster with HCCP.
Changes in Bone Marrow Fatty Acids Early after Ovariectomy-Induced Osteoporosis in Rats and Potential Functions
Authors: Wang Sizhu , Tang Cuisong , Chen Jieying , Tang Huan , Zhang Lin , Tang Guangyu
Published: December 2022

The aim of this study was to investigate the changes in bone marrow fatty acids early after ovariectomy-induced osteoporosis in rats, and explore the potential function of the bone marrow fatty acids. Ninety-six female Sprague Dawley rats (12 weeks) were randomly divided into an ovariectomized (OVX) group and Sham group (N = 48/group) and received ovariectomy or Sham surgery, respectively. After 3, 5, 7,14, 21 and 28 days, eight rats in each group were sacrificed to detect the composition of bone marrow fatty acids by means of gas chromatography-mass spectrometry and evaluate the trabecular bone microarchitecture by means of microCT. Bone marrow rinsing fluid and serum were collected for the detection of nitric oxide synthase/nitric oxide (NOS/NO) and bone metabolism related parameters, respectively. Our results demonstrated that the bone microstructure was damaged significantly from 14 days after OVX surgery onwards. Sample clustering and group separation were observed between the OVX group and Sham group 3 and 14 days after surgery, which suggested the role of bone marrow fatty acids in the early stage of postmenopausal osteoporosis. Palmitoleate, myristate and arachidonate were found to play an important role in classification between the OVX group and Sham group on the 3rd day after surgery (VIP > 1, p < 0.05). Palmitoleate, myristate, alpha linolenate, stearate and eicosenoate were found to play an important role in classification between the OVX group and Sham group on the 14th day after surgery (VIP > 1, p < 0.05). The levels of myristate, palmitoleate, alpha linolenate and eicosenoate were significantly decreased in the OVX group, while the levels of arachidonate and stearate were significantly increased in OVX group (p < 0.05). Additionally, myristate, palmitoleate, alpha linoleate and eicosenoate were negatively correlated with C-terminal telopeptide of type 1 collagen (CTX-1, a bone resorption marker), while arachidonate was negative correlated with osteocalcin (OCN, a bone formation marker) (p < 0.05). A significant correlation was also found between eicosenoate and NOS (p < 0.05). Profound bone marrow fatty acids changes have taken place in the early stage of post-menopausal osteoporosis. They may affect bone formation though affecting the differentiation and function of osteoclasts or osteoblasts, respectively. The NOS/NO system may mediate the influence of eicosenoate on bone formation.
Drain-Source Voltage-Controllable Three-Switch Active-Clamp Forward Converter for Wide Input/Output Voltage Applications
Authors: Lim Jeong-Woo , Kim Chong-Eun
Published: December 2022

Active-clamp forward converters are applied to various medium-capacity power systems because they have a relatively simple structure and are capable of zero-voltage switching. In particular, there is the advantage that a stable output voltage can be obtained by controlling the duty ratio of the power semiconductor switch even in applications with wide input and output voltage ranges. However, the voltage stress on the power semiconductor switches due to the application of active clamp is higher than the input voltage, especially as the duty ratio increases. A three-switch active-clamp forward converter is proposed, which can overcome such shortcomings and can reduce the voltage stress of the power semiconductor switches, but it causes an increase in the DC bias of the magnetizing current and the additional conduction and switching losses. Therefore, in this paper, a voltage-stress-controllable three-switch active-clamp forward converter that can utilize both advantages of the conventional active-clamp forward converter and three-switch active clamp forward converter is proposed and verified through a prototype for 800 W battery charger.
Approximate Packing of Binary Mixtures of Cylindrical Particles
Authors: Iniyatova Gulfairuz , Yermukhambetova Assiya , Boribayeva Aidana , Golman Boris
Published: December 2022

Particle packing plays an essential role in industry and chemical engineering. In this work, the discrete element method is used to generate the cylindrical particles and densify the binary cylindrical particle mixtures under the poured packing conditions. The influences of the aspect ratio and volume fraction of particles on the packing structure are measured by planar packing fraction. The Voronoi tessellation is used to quantify the porous structure of packing. The cumulative distribution functions of local packing fractions and the probability distributions of the reduced free volume of Voronoi cells are calculated to describe the local packing characteristics of binary mixtures with different volume fractions. As a result, it is observed that particles with larger aspect ratios in the binary mixture tend to orient randomly, and the particles with smaller aspect ratios have a preferentially horizontal orientation. Results also show that the less dense packings are obtained for mixtures with particles of higher aspect ratios and mixtures with a larger fraction of elongated cylindrical particles.
Microfluidic Chip for Detection of Drug Resistance at the Single-cell Level
Authors: Song Kena , Yu Zhangqing , Zu Xiangyang , Huang Lei , Fu Dongliao , Yao Jingru , Hu Zhigang , Xue Yun
Published: December 2022

Drug-resistant bacterial strains seriously threaten human health. Rapid screening of antibiotics is urgently required to improve clinical treatment. Conventional methods of antimicrobial susceptibility testing rely on turbidimetry that is evident only after several days of incubation. The lengthy time of the assay can delay clinical treatment. Here, we proposed a single-cell level rapid system based on a microfluidic chip. The detection period of 30 min to 2 h was significantly shorter than the conventional turbidity-based method. To promote detection efficiency, 16 independent channels were designed, permitting the simultaneous screening of 16 drugs in the microfluidic chip. Prepositioning of drugs in the chip permitted prolonged transportation and storage. This may allow for the widespread use of the novel system, particularly in the regions where medical facilities are scarce. The growth curves were reported rapidly through a custom code in Matlab after tracking and photographing the bacteria during microscopy examination. The capability of the proposed system was validated by antimicrobial susceptibility testing trials with standard strains. The system provides a potentially useful detection tool for drug-resistant bacteria.
Numerical Investigation of Darcy–Forchheimer Hybrid Nanofluid Flow with Energy Transfer over a Spinning Fluctuating Disk under the Influence of Chemical Reaction and Heat Source
Authors: Khan Muhammad Riaz , Alqahtani Aisha M. , Alhazmi Sharifah E. , Elkotb Mohamed Abdelghany , Sidi Maawiya Ould , Alrihieli Haifaa F. , Tag-Eldin Elsayed , Yassen Mansour F.
Published: December 2022

The present computational model is built to analyze the energy and mass transition rate through a copper and cobalt ferrite water-based hybrid nanofluid (hnf) flow caused by the fluctuating wavy spinning disk. Cobalt ferrite (CoFe2O4) and copper (Cu) nanoparticles (nps) are incredibly renowned in engineering and technological research due to their vast potential applications in nano/microscale structures, devices, materials, and systems related to micro- and nanotechnology. The flow mechanism has been formulated in the form of a nonlinear set of PDEs. That set of PDEs has been further reduced to the system of ODEs through resemblance replacements and computationally solved through the parametric continuation method. The outcomes are verified with the Matlab program bvp4c, for accuracy purposes. The statistical outputs and graphical evaluation of physical factors versus velocity, energy, and mass outlines are given through tables and figures. The configuration of a circulating disk affects the energy transformation and velocity distribution desirably. In comparison to a uniform interface, the uneven spinning surface augments energy communication by up to 15%. The addition of nanostructured materials (cobalt ferrite and copper) dramatically improves the solvent physiochemical characteristics. Furthermore, the upward and downward oscillation of the rotating disc also enhances the velocity and energy distribution.
Removal Modeling and Experimental Verification of Magnetorheological Polishing Fused Silica Glass
Authors: Zhang Limin , Li Weixing , Zhou Jiakang , Lu Mingming , Liu Qiang , Du Yongsheng , Yang Yakun
Published: December 2022

Compared to conventional polishing methods, magnetorheological polishing has no subsurface damage and a has good polishing effect, which is suitable for fused silica glass surface processing. However, the existing magnetorheological polishing material removal model has low processing efficiency and uneven removal, which cannot realize the deterministic processing of parts. The material removal (MR) model of fused silica glass is established by convolving the dwell time with the material removal function. The residence time is Fourier transformed. The consequence of process variable such as machining time, workpiece rotational frequency, machining gap and X-direction deflection on the MR of workpiece interface are analyzed. Experiments verify the validity of the material removal model. The surface precision PV value of the workpiece surface under the optimal process parameters was decreased from 7.959 nm to 0.609 nm for machining. The experiment results indicate that the established MR model can be implemented as the deterministic MR of the optical surface and ameliorate the surface accuracy of the workpiece surface.
Crack-Based Sensor by Using the UV Curable Polyurethane-Acrylate Coated Film with V-Groove Arrays
Authors: Park Jongsung , Kim Dong-Su , Yoon Youngsam , Shanmugasundaram Arunkumar , Lee Dong-Weon
Published: December 2022

Over the years, several bare metal and crack-based strain sensors have been proposed for various fields of science and technology. However, due to their low gauge factor, metal-based strain sensors have limited practical applications. The crack-based strain sensor, on the other hand, demonstrated excellent sensitivity and a high gauge factor. However, the crack-based strain sensor exhibited non-linear behavior at low strains, severely limiting its real-time applications. Generally, the crack-based strain sensors are fabricated by generating cracks by bending a polymer film on which a metal layer has been deposited with a constant curvature. However, the random formation of cracks produces nonlinear behavior in the crack sensors. To overcome the limitations of the current state of the art, we propose a V-groove-based metal strain sensor for human motion monitoring and Morse code generation. The V-groove crack-based strain sensor is fabricated on polyurethane acrylate (PUA) using the modified photolithography technique. During the procedure, a V-groove pattern formed on the surface of the sensor, and a uniform crack formed over the entire surface by concentrating stress along the groove. To improve the sensitivity and selectivity of the sensor, we generated the cracks in a controlled direction. The proposed strain sensor exhibited high sensitivity and excellent fidelity compared to the other reported metal strain sensors. The gauge factor of the proposed V-groove-induced crack sensor is 10-fold higher than the gauge factor of the reported metal strain sensors. In addition, the fabricated V-groove-based strain sensor exhibited rapid response and recovery times. The practical feasibility of the proposed V-groove-induced crack-based strain sensor is demonstrated through human motion monitoring and the generation of Morse code. The proposed V-groove crack sensor can detect multiple motions in a variety of human activities and is anticipated to be utilized in several applications due to its high durability and reproducibility.