Search Results (19)

Infertility affects about 17.5% of couples, with male factors accounting for approximately 50% of cases. Cytoskeletal remodeling is increasingly recognized as a critical component of male reproductive function, particularly in the regulation of testosterone synthesis by Leydig cells. However, the underlying molecular mechanisms remain poorly defined. Rho-associated coiled-coil-containing kinase (ROCK), a key cytoskeletal regulator, influences actin dynamics, impacting intracellular trafficking. In this study, we investigated the roles of ROCK1 and ROCK2 in Leydig cells using the TM3 cell model. Pharmacological inhibition of ROCK activity with Y-27632 impaired actin cytoskeleton organization, reduced the phosphorylation of LIMK, COFILIN, and MLC2, and disrupted the colocalization of F-actin with StAR and cholesterol, thereby decreasing testosterone production. Furthermore, RNA-seq revealed that hCG promotes transcription of steroidogenesis-related genes, while ROCK inhibition reverses this effect. Silencing of ROCK1 via siRNA mimicked the effects of ROCK-i, suppressing steroidogenic gene expression and testosterone synthesis. In contrast, ROCK2 knockdown enhanced testosterone secretion, promoted F-actin remodeling, and increased traffic of cholesterol targeting mitochondria. These opposing effects triggered distinct responses in the SCAP–SREBP2 axis, indicating a feedback mechanism regulating cholesterol homeostasis. Collectively, our findings uncover the isoform-specific roles of ROCK1 and ROCK2 in coordinating cytoskeletal dynamics and steroidogenic activity, providing new insights into the regulation of male reproductive endocrinology and identifying potential therapeutic targets for androgen deficiency and male infertility. Full article

The Xintianling deposit, a skarn-type tungsten mineralization system in the Nanling Range of South China, presents significant challenges in identifying new high-grade orebodies. This study employs an integrated approach, combining the opposing-coil transient electromagnetic (OCTEM) method with geochemical exploration, to delineate and evaluate concealed mineralization within and beyond the known mining area. High-precision geophysical surveys revealed low-resistivity anomalies along the contact zone between Jurassic granite and the Carboniferous Shidengzi Formation limestone. Integration of these anomalies with geochemical element associations (W-Sn-Fe-Bi and Cu-Mo-As) highlights signatures indicative of tungsten mineralization. The results demonstrate that skarn-type orebodies in the mining area are primarily controlled by the axial planes of N–S-striking anticlines and associated secondary folds, with thick, large orebodies preferentially forming in depressions along the granite roof. Comprehensive analysis of the geophysical and geochemical data identified 15 low-resistivity anomalies in the Shanglongshan–Huanggualing target area, of which 14 are interpreted as potential skarn-type mineralized bodies, thereby delineating three potential exploration targets. This integrated methodology establishes a robust scientific foundation for deep and peripheral prospecting in the mining area and provides methodological guidance for exploring similar skarn-type tungsten deposits. Full article

The small-loop transient electromagnetic method (TEM) refers to a system in which the coil frame length or diameter is less than 2 m. Due to the inductive effects of the multi-turn coils used for both transmission and reception, the induced electromotive force in the measuring coil increases, causing a reduction in the decay rate and an extension of the shutoff time. This results in coupling between the primary and secondary fields in early-time signals, making them difficult to separate and creating a detection blind spot in the shallow subsurface. The opposing coil TEM transmission and reception method can significantly reduce early-time signal distortion caused by coil inductance. However, this approach is constrained by the physical symmetry of the coil dimensions, which makes it challenging to achieve balance in a zero-field space. By performing both forward and reverse measurements at the same location using the opposing coil setup and calculating the difference between the signals, the inductive coupling between coils at the measurement site can theoretically be eliminated. This eliminates the induced potential of the TEM signal, enhancing the induced electromotive force from the formation. As a result, more accurate resistivity values are obtained, detection blind spots are eliminated, and the resolution in shallow TEM exploration is improved. Field experiments were conducted to validate the method on both high-resistivity and low-resistivity anomalies. The results demonstrated that this method effectively identified a high-resistivity corrugated pipe at a depth of 1.2 m and two low-resistivity gas pipelines at a depth of 2 m, thereby essentially eliminating detection blind spots in the shallow subsurface. Full article

Friction in marine engineering machinery produces abrasive particles containing valuable information. By employing oil detection technology, we can analyze these particles to monitor and diagnose mechanical system faults. This paper introduces an inductive oil detection sensor and wireless signal transmission circuit. The sensor utilizes two opposing solenoid coils of the same specifications, with the detection coil connected to a chip capacitor to form an LC resonant unit. The designed wireless transmission circuit wirelessly transmits a sensing signal from a detection coil to a receiving coil to detect metal particles in oil. This paper deduces the sensor’s inductance principle and simulates the magnetic field distribution using finite element simulation software. Through experiments, the optimal excitation frequency, coil spacing, and oil sample flow path location were determined. The sensor successfully detected 55 μm iron particles and 138 μm copper particles in a 1 mm microfluidic channel. With its simple structure, distinct signal characteristics, and high sensitivity, the sensor is suitable for detecting metal abrasive particles in hydraulic oil, providing a new approach for wireless transmission in oil detection sensors. Full article

Additive Manufacturing (AM) Direct Laser Fabrication (DLF) of Ti-5Al-5V-5Mo-3Cr (Ti5553) is being developed as a method for producing aircraft components. The additive manufacturing process can produce flaws near the surface, such as porosity and material voids, which act as stress raisers, leading to potential component failure. Eddy current testing was investigated to detect flaws on or near the surface of DLF Ti5553 bar samples. For this application, the objective was to develop an eddy current probe capable of detecting flaws 500 µm in diameter, located 1 mm below the component’s surface. Two initial sets of coil parameters were chosen: The first, based on successful experiments that demonstrated detection of a near surface flaw in Ti5553 using a transmit-receive array probe, and the second, derived from simulation by Finite Element Method (FEM). An optimized transmit receive coil design, based on the FEM simulations, was constructed. The probe was evaluated on Ti5553 samples containing sub-surface voids of the target size, as well as samples with side-drilled holes and samples with holes drilled from the opposing inspection surface. The probe was able to effectively detect 80% of the sub-surface voids. Limitations included the probe’s inability to detect sub-surface voids near sample edges and a sensitivity to surface roughness, which produces local changes in lift-off. Multifrequency mixing improved signal-to-noise ratio when surface roughness was present on average by 22%. A probe based on that described in this paper could benefit quality assurance of additively manufactured aircraft components. Full article

Water is an essential element for human survival, yet many individuals still lack access to treated water to meet their basic needs. To mitigate this situation, alternative water treatment technologies that are accessible and easy to handle are being explored. Among these, the use of Moringa oleifera seeds as a natural coagulant and the application of a helically coiled tube as a flocculation unit have been studied. In this context, this study aimed to evaluate the turbidity removal efficiency using two different coagulants (Moringa oleifera and aluminum sulfate) in an alternative water clarification system. The system consists of a helically coiled tube flocculator (HCTF) coupled with a conventional decantation unit. It was observed that the coagulant solution from shelled seeds required a lower dosage to achieve efficiencies above 90% compared to the coagulant solution from seeds with shells. The optimal dosage was 30 mL/L of the coagulant solution from shelled seeds. This dosage resulted in high turbidity-removal efficiencies, ranging from 92% to 100%. The processing method of the seeds that yielded the highest efficiency in turbidity removal was the mortar and pestle, as opposed to a blender. The optimal configuration of the alternative water clarification system comprised using the lower HCTF in a horizontal orientation. The use of the alternative water clarification system, along with the natural coagulant, proves to be a promising alternative clean technology for water clarification in locations without access to conventional treatment, being efficient in turbidity removal. Full article

Typical radial active magnetic bearings are structurally symmetric. For example, an eight-pole bearing uses two opposing pairs to control one axis by winding the pair in series. The magnetic force produced by an active magnetic bearing is quadratically proportional to coil currents and inversely proportional to the square of the gap between the bearing and the journal. Bias linearization is widely used to linearize the relationship of coil currents to the magnetic force. However, the bias currents increase ohmic losses and require a larger than necessary capacity of power amplifiers to supply the sum of bias and control currents. Unbiased control of symmetric bearings has the critical issue of slew-rate limiting. Unbiased control of unsymmetrical bearings can eliminate the need for bias currents while avoiding slew-rate singularity except in extreme cases. Although a generalized inversion of the force–current relationship of unbiased unsymmetrical bearings has been proposed previously, no experimental validation is reported. The main objective of this research is to implement the unbiased control strategy and show that exactly the same linear control strategy for eight-pole symmetric bearings can be applied to nine-pole unsymmetrical bearings on industry-scale compressor test rigs. Two test rigs are built: one with eight-pole symmetric bearings and another with nine-pole unsymmetrical bearings. Linear control algorithms are designed and applied. Both control algorithms are linear and consist of lead filters and notch filters. The test results show that the linear control design used for unsymmetrical bearings can achieve the same level of stability that the symmetric bearings provide, satisfying the sensitivity criterion specified by ISO 14839-3. Full article

The caving method and mining disturbance may cause geological issues. The advance prediction of unfavorable geological bodies should be conducted to ensure product safety in the underground mine. In this study, we proposed the OCTEM-PHA analysis process and analyzed the Tongkeng Mine in Guangxi. Further, we conducted opposing-coil transient electromagnetic method (OCTEM) detection on four detection lines in T5-1 stope at mine level 386 by using portable geological remote sensing equipment and created inversion maps. Plot profiles and coupling were analyzed with inversion maps to explore the five types of risk factors presented in the mine. The preliminary hazard analysis (PHA) method was used for five types of risk factors to predict the accident consequence and develop safety countermeasures. The results indicate the following: (1) the OCTEM-PHA safety analysis process for unfavorable geological bodies is realistic and feasible. (2) OCTEM shows an excellent response to both high- and low-resistance anomalies in practical engineering applications. The coupling analysis of profiles and inversion maps helps visually analyze the area of apparent resistivity anomalies. (3) The studied mine did not show overhanging formed by the overlying rock layer and large loose void areas. However, the crumbling mining area should be further optimized for balanced mining, the treatment of groundwater and surface water should be improved, and the comparative analysis with the follow-up detection results should be increased. Full article

Hypercoagulability and formation of extensive and difficult-to-lyse microclots are a hallmark of both acute COVID-19 and long COVID. Fibrinogen, when converted to fibrin, is responsible for clot formation, but abnormal structural and mechanical clot properties can lead to pathologic thrombosis. Recent experimental evidence suggests that the spike protein (SP) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may directly bind to the blood coagulation factor fibrinogen and induce structurally abnormal blood clots with heightened proinflammatory activity. Accordingly, in this study, we used molecular docking and molecular dynamics simulations to explore the potential activity of the antiparasitic drug ivermectin (IVM) to prevent the binding of the SARS-CoV-2 SP to fibrinogen and reduce the occurrence of microclots. Our computational results indicate that IVM may bind with high affinity to multiple sites on the fibrinogen peptide, with binding more likely in the central, E region, and in the coiled-coil region, as opposed to the globular D region. Taken together, our in silico results suggest that IVM may interfere with SP–fibrinogen binding and, potentially, decrease the formation of fibrin clots resistant to degradation. Additional in vitro studies are warranted to validate whether IVM binding to fibrinogen is sufficiently stable to prevent interaction with the SP, and potentially reduce its thrombo-inflammatory effect in vivo. Full article

Leakage in the impervious layer of a domestic waste landfill seriously pollutes the soil and groundwater. Therefore, it is necessary to carry out rapid nondestructive leakage location detection. In this research, the electrical resistivity tomography (ERT) method and the opposing-coils transient electromagnetic method (OCTEM) were used to detect the leakage location. The inversion sections of both methods showed a clear low–middle–high resistivity spectrum in the longitudinal direction that could be used to speculate the distribution pattern of the upper waste body layer, the bottom impermeable layer, and the lower limestone layer. The leakage area was identified in Zone B of the landfill on the basis of inversion results and drilling verification results. The results indicate that OCTEM and ERT were both sensitive to leakage detection. However, OCTEM had higher longitudinal resolution and more refined inversion results, resulting in more effective delineation for the location of the damage and leakage of the impervious landfill layer, thereby providing a new technical basis for landfill leakage detection. Full article

In this project, we combine two areas of research, experimental characterization and molecular docking studies of the interaction of positively charged oligopeptides with crucial blood plasma proteins. The investigated peptides are rich in NH₂ groups of amino acid side chains from Dap, Orn, Lys, and Arg residues, which are relevant in protein interaction. The peptides are 9- and 11-mer with the following sequences: (Lys-Dab-Dab-Gly-Orn-Pro-His-Lys-Arg-Lys-Dbt), (Lys-Dab-Ala-Gly-Orn-Pro-His-Lys-Arg), and (Lys-Dab-Dab-Gly-Orn-Pro-Phe(2-F)-Lys-Arg). The net charge of the compound strongly depends on the pH environment and it is an important aspect of protein binding. The studied oligopeptides exhibit therapeutic properties: anti-inflammatory activity and the capacity to diminish reactive oxygen species (ROS). Therefore, the mechanism of potential binding with blood plasma components is the next challenge. The binding interaction has been investigated under pseudo-physiological conditions with the main blood plasma proteins: albumin (BSA), α1-acid glycoprotein (AAG), and γ-globulin fraction (GGF). The biomolecular quenching constant (k_q) and binding constant (K_b) were obtained by fluorescence spectroscopy at various temperatures. Simultaneously, the changes in the secondary structure of proteins were monitored by circular dichroism (CD) and infrared spectroscopy (IR) by quantity analysis. Moreover, molecular docking studies were conducted to estimate the binding affinity, the binding domain, and the chemical nature of these interactions. The results show that the investigated oligopeptides could be mainly transported by albumin, and the binding domain I is the most favored cavity. The BSA and GGF are able to form stable complexes with the studied compounds as opposed to AAG. The binding reactions are spontaneous processes. The highest binding constants were determined for Lys-Dab-Dab-Gly-Orn-Pro-His-Lys-Arg-Lys-Dbt peptide, in which the values of the binding constants K_b to BSA and GGF were 10.1 × 10⁴ dm³mol⁻¹ and 3.39 × 10³ dm³mol⁻¹, respectively. The positively charged surface of peptides participated in salt bridge interaction with proteins; however, hydrogen bonds were also formed. The secondary structure of BSA and GGF after contact with peptides was changed. A reduction in the α-helix structure was observed with an increase in the β-sheet and β-turn and random coil structures. Full article

To lessen the amount of energy lost during transmission, electricity is increasingly being sent using high-voltage lines. Transmission loss in a DC system is lower than in an AC system over long distances. The DC system can improve the efficiency of long-distance transmission by connecting power grids with different requirements. The DC method is becoming popular since it helps to keep the grid stable. Managing and blocking DC flow is crucial to system functionality. In this study, we explore the operation of a flux-coupled type superconducting fault current limiter (SFCL) in a DC system, where the two windings are connected in parallel to limit the fault current flow. A flux-coupled type SFCL is built by connecting two coils in parallel and a superconducting element (SE) in series with the secondary coil. The functions of an SFCL of the flux-coupled kind are equivalent in both direct and alternating current systems. Because of the opposing magnetic fluxes produced by the two coils, the voltage generated by the parallel connection of the coils is always zero. Inadequate SE leads to an increase in resistance, inhibiting the cancellation of opposing magnetic fluxes and hence a loss in power. Connecting the two coils in series allows voltage to be generated while the fault current is limited. To further validate the performance of SFCL with varying resistance and inductance, the system is additionally tested on the IEEE 39 bus system. The MATLAB/SIMULINK software suite is used to run the test system. Full article

The current exploration aims to inspect the features of thermal radiation on the buoyancy or mixed convective fluid flow induced by nanofluid through a stretching permeable bended sheet. The impact of activation energy and binary reaction along with slip migration is taken into account to discuss the fine points of water-based alumina nanoparticle flow. The structure of the curved sheet is assumed to be stretchable and the bended texture is coiled within a circular section with radius $R_b$. The similarity technique is utilized to reduce the leading partial differential equations into ordinary differential equations. These reduced equations are then deciphered numerically by employing the bvp4c method. The outcomes of the model were constructed in the form of several figures and bar graphs for the case of opposing and assisting flows with varying distinct embedded control parameters. The results display that the velocity field curves escalate with a higher radius of curvature parameter while temperature and concentration profiles shrink. More precisely, the outcomes show that the temperature distribution profile increases with the increase in nanoparticle’s volume fraction as well as thermal radiation parameter. Meanwhile, the concentration and velocity fields are decelerated with higher impacts of nanoparticle volume fraction. In addition, the heat and mass transfer rates were significantly improved for the higher value of the radiation and Schmidt number. On the other hand, the growing values of the velocity slip factor decrease the shear stress. Furthermore, the results are compared with the previous results in the limiting cases and observed a tremendous harmony. Full article

We present in this paper a method of improving a coil gun circuit’s energy efficiency and acceleration performance. Particularly, the improvement was performed by designing a solenoid coil and capacitance for projectile velocity enhancement in a multi-stage coil gun, based on simulations and experiments. A projectile decelerates in coil guns when passing through the solenoid coil’s center by being subjugated to a force opposing the launch direction. Thus, we achieved the efficient distribution of the electromagnetic power delivered from the circuit to the projectile by adjusting the capacitance according to the solenoid coil’s shape. This produced a current shape suitable for projectile acceleration, consequently enhancing its performance. Designing the coil using 1.3 mm diameter copper wires, among the coils using copper wires of various diameters, to increase the number of turns and reduce the capacitance improved the energy efficiency while enhancing the acceleration performance. Finally, each stage’s measured and simulated velocities in the coil gun were analyzed and compared. Accordingly, we arrived at an efficient design method for multi-stage coil gun systems. Full article

Investigating the coil–magnet structure plays a significant role in the design process of the electromagnetic energy harvester due to the effect on the harvester’s performance. In this paper, the performance of four different electromagnetic vibration energy harvesters with cylindrical shapes constrained in the same volume were under investigation. The utilized structures are (i) two opposite polarized magnets spaced by a mild steel; (ii) a Halbach array with three magnets and one coil; (iii) a Halbach array with five magnets and one coil; and (iv) a Halbach array with five magnets and three coils. We utilized a completely automatic optimization procedure with the help of an optimization algorithm implemented in Python, supported by simulations in ANSYS Maxwell and MATLAB Simulink to obtain the maximum output power for each configuration. The simulation results show that the Halbach array with three magnets and one coil is the best for configurations with the Halbach array. Additionally, among all configurations, the harvester with two opposing magnets provides the highest output power and volume power density, while the Halbach array with three magnets and one coil provides the highest mass power density. The paper also demonstrates limitations of using the electromagnetic coupling coefficient as a metric for harvester optimization, if the ultimate goal is maximization of output power. Full article