Search Results (2,151)

Barrel tools are increasingly used in high-precision machining of free-form surfaces. However, limited studies evaluate their performance specifically on spherical geometries, where tool–surface contact characteristics differ significantly. Understanding how tool geometry and process parameters influence surface quality and cutting forces in such cases remains underexplored. This study evaluates how barrel cutter radius and varying machining parameters affect cutting forces and surface roughness when milling internal and external spherical surfaces. Machining tests were conducted on structural steel 1.1191 using two barrel cutters with different curvature radii (85 mm and 250 mm) on a 5-axis CNC machine. Feed per tooth and radial depth of cut were systematically varied. Cutting forces were measured using a dynamometer, and surface roughness was assessed using the Rz parameter, which is more sensitive to peak deviations than Ra. Novelty lies in isolating spherical surface shapes (internal vs. external) under identical path trajectories and systematically correlating tool geometry to force and surface metrics. The larger curvature tool (250 mm) consistently generated up to twice the cutting force of the smaller radius tool under equivalent conditions. External surfaces showed higher Rz values than internal ones due to less favorable contact geometry. Radial depth of the cut had a linear influence on force magnitude, while feed rate had a limited effect except at higher depths. Smaller-radius barrel tools and internal geometries are preferable for minimizing cutting forces and achieving better surface quality when machining spherical components. The aim of this paper is to determine the actual force load and surface quality when using specific cutting conditions for internal and external spherical machined surfaces. Full article

This article analyzes the operating principle of the BMM sensor emitter in order to improve the accuracy of the wireless determination of the BMM sensor coordinates under a massif of destroyed rock in the context of the problem of determining the shift of rocks during gold ore mining. Using numerical simulations, FEM has been developed to develop digital models reflecting individual cases of the propagation of the magnetic field of the emitter located in various geological conditions and positions relative to the rock surface and the vertical axis. The accuracy of determining the coordinates of the radio beacon in the rock has been analyzed, and data on the deviation of the coordinates of the peaks of the magnetic field strength from the radio beacon axis have been obtained in cases of a heterogeneous composition of the rock massif, the influence of the deviation of the emitter axis angle from the vertical, the influence of the unevenness of the collapse relief, and the influence of the superposition of fields from different radiation sources. A study has been carried out to determine the direction of the radio beacon search based on the resulting vector of the emitter’s magnetic field strength. Full article

Temporomandibular disorders (TMDs) encompass a heterogeneous group of musculoskeletal and neuromuscular conditions affecting the temporomandibular joint (TMJ) and masticatory system. Due to academic stress and parafunctional habits, dental students may be particularly vulnerable to TMD. Objective: To determine the prevalence of TMD symptoms and their psychosocial and functional correlates among students at the Faculty of Dental Medicine, UMPh Iasi, Romania, using the diagnostic criteria for TMD (DC/TMD) self-report axis and axis II instruments. Methods: In this cross-sectional survey, 356 volunteer students (66.0% female; mean age, 22.9 ± 3.6 years) out of a total population of 1874 completed an online DC/TMD–based questionnaire. Axis I assessed orofacial pain, joint noises, and mandibular locking. Axis II instruments included the Graded Chronic Pain Scale (GCPS), Jaw Functional Limitation Scale (JFLS-20), Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Oral Behaviors Checklist (OBC). Descriptive statistics summarized frequencies, means, and standard deviations; χ² tests and t-tests compared subgroups by sex; Pearson correlations explored relationships among continuous measures (α = 0.05). Results: A total of 5% of respondents reported orofacial pain in the past 30 days; 41.6% observed TMJ noises; 19.7% experienced locking episodes. Mean JFLS score was 28.3 ± 30.5, with 4.8% scoring > 80 (severe limitation). Mean PHQ-9 was 5.96 ± 5.37 (mild depression); 15.5% scored ≥ 10. Mean GAD-7 was 5.20 ± 4.95 (mild anxiety); 16.0% scored ≥ 10. Mean OBC score was 12.3 ± 8.5; 30.1% scored ≥ 16, indicating frequent parafunctional habits. Symptom prevalence was similar by sex, except temporal headache (43.4% females vs. 24.3% males; p = 0.0008). Females reported higher mean scores for pain intensity (2.09 vs. 1.55; p = 0.0013), JFLS (32.5 vs. 18.0; p < 0.001), PHQ-9 (6.43 vs. 5.16; p = 0.048), and OBC (13.9 vs. 9.7; p = 0.0014). Strong correlation was observed between PHQ-9 and GAD-7 (r = 0.74; p < 0.001); moderate correlations were observed between pain intensity and PHQ-9 (r = 0.31) or GAD-7 (r = 0.30), between JFLS and pain intensity (r = 0.33), and between OBC and PHQ-9 (r = 0.39) (all p < 0.001). Conclusions: Nearly half of dental students reported TMD symptoms, with appreciable functional limitation and psychosocial impact. Parafunctional behaviors and psychological distress were significantly associated with pain and dysfunction. These findings underscore the need for early screening, stress-management interventions, and interdisciplinary care strategies in the dental student population. Full article

The aim of this study was to determine the connection between oscillations in operating pressure values and the appearance of various irregularities on machined surfaces. Such oscillations are a consequence of the high water pressure generated during abrasive water jet machining. Oscillations in the operating pressure values are periodic, namely due to the cyclic operation of the intensifier and the physical characteristics of water. One of the most common means of reducing this phenomenon is installing an attenuator in the hydraulic system or a phased intensifier system. The main hypothesis of this study was that the topography of a machined surface is directly influenced by the inability of the pressure accumulator to fully absorb water pressure oscillations. In this study, we monitored changes in hydraulic oil pressure values at the intensifier entrance and their connection with irregularities on the machined surface—such as waviness—when cutting aluminum AlMg3 of different thicknesses. Experimental research was conducted in order to establish this connection. Aluminum AlMg3 of different thicknesses—from 6 mm to 12 mm—was cut with different traverse speeds while hydraulic oil pressure values were monitored. The pressure signals thus obtained were analyzed by applying the fast Fourier transform (FFT) algorithm. We identified a single-sided pressure signal amplitude spectrum. The frequency axis can be transformed by multiplying inverse frequency data with traverse speed; in this way, a single-sided amplitude spectrum can be obtained, examined against the period in which striations are expected to appear (in millimeters). In the lower zone of the analyzed samples, striations are observed at intervals determined by the dominant hydraulic oil pressure harmonics, which are transferred to the operating pressure. In other words, we demonstrate how the machined surface topography is directly induced by water jet pressure frequency characteristics. Full article

Background/Objectives: Autism spectrum disorder (ASD) encompasses several neurodevelopmental disorders, whose onset is correlated to genetic and environmental factors. Although the etiopathogenesis is not entirely clear, the involvement of inflammatory processes, the endocannabinoid system, and alterations in the permeability and composition of the intestinal microbiota are known to occur. Methods: This review systematically explores the literature available to date on the most widely used murine models for the study of ASD, the main biomarkers investigated for the diagnosis of ASD, and the therapeutic potential of probiotics, with a particular focus on the use of strains of Lactiplantibacillus (Lpb.) plantarum in in vivo models and clinical trials for ASD. Results: Several studies have demonstrated that targeting multifactorial biomarkers in animal models and patients contributes to a more comprehensive understanding of the complex mechanisms underlying ASD. Moreover, accumulating evidence supports the beneficial effect of probiotics, including Lpb. plantarum, as a promising alternative therapeutic strategy, capable of modulating gut–brain axis communication. Conclusions: Probiotic supplementation, particularly with selected Lpb. plantarum strains, is emerging as a potential complementary approach for ameliorating ASD-related gastrointestinal and behavioral symptoms. However, further large-scale clinical studies are essential to validate their efficacy and determine optimal treatment protocols and dietary strategies. Full article

Background: Protein kinase R (PKR) inhibits general mRNA translation by phosphorylating the alpha subunit of eukaryotic translation initiation factor 2 (eIF2). PKR also modulates NF-κB signaling during viral infections, but comparative studies of PKR-mediated NF-κB responses across mammalian species and their regulation by viral inhibitors remain largely unexplored. This study aimed to characterize the conserved antiviral and inflammatory roles of mammalian PKR orthologs and investigate their modulation by poxviral inhibitors. Methods: Using reporter gene assays and quantitative RT-PCR, we assessed the impact of 17 mammalian PKR orthologs on general translation inhibition, stress-responsive translation, and NF-κB-dependent induction of target genes. Congenic human and rabbit cell lines infected with a myxoma virus strain lacking PKR inhibitors were used to compare the effects of human and rabbit PKR on viral replication and inflammatory responses. Site-directed mutagenesis was employed to determine key residues responsible for differential sensitivity to the viral inhibitor M156. Results: All 17 mammalian PKR orthologs significantly inhibited general translation, strongly activated stress-responsive ATF4 translation, and robustly induced NF-κB target genes. Inhibition of these responses was specifically mediated by poxviral K3 orthologs that effectively suppressed PKR activation. Comparative analyses showed human and rabbit PKRs similarly inhibited virus replication and induced cytokine transcripts. Amino acid swaps between rabbit PKRs reversed their sensitivity to viral inhibitor M156 and NF-κB activation. Conclusions: Our data show that the tested PKR orthologs exhibit conserved dual antiviral and inflammatory regulatory roles, which can be antagonized by poxviral K3 orthologs that exploit eIF2α mimicry to modulate the PKR-NF-κB axis. Full article

In mining areas with high groundwater levels, intensive coal mining has led to the accumulation of substantial surface water and significant alterations in regional landscape patterns. Reconstructing the ecological security pattern (ESP) has emerged as a critical focus for ecological restoration in coal mining subsidence areas with high groundwater levels. This study employed the patch-generating land use simulation (PLUS) model to predict the landscape evolution trend of the study area in 2032 under three scenarios, combining environmental characteristics and disturbance features of coal mining subsidence areas with high groundwater levels. In order to determine the differences in ecological network changes within the study area under various development scenarios, morphological spatial pattern analysis (MSPA) and landscape connectivity analysis were employed to identify ecological source areas and establish ecological corridors using circuit theory. Based on the simulation results of the optimal development scenario, potential ecological pinch points and ecological barrier points were further identified. The findings indicate that: (1) land use changes predominantly occur in urban fringe areas and coal mining subsidence areas. In the land reclamation (LR) scenario, the reduction in cultivated land area is minimal, whereas in the economic development (ED) scenario, construction land exhibits a marked increasing trend. Under the natural development (ND) scenario, forest land and water expand most significantly, thereby maximizing ecological space. (2) Under the ND scenario, the number and distribution of ecological source areas and ecological corridors reach their peak, leading to an enhanced ecological network structure that positively contributes to corridor improvement. (3) By comparing the ESP in the ND scenario in 2032 with that in 2022, the number and area of ecological barrier points increase substantially while the number and area of ecological pinch points decrease. These areas should be prioritized for ecological protection and restoration. Based on the scenario simulation results, this study proposes a planning objective for a “one axis, four belts, and four zones” ESP, along with corresponding strategies for ecological protection and restoration. This research provides a crucial foundation for decision-making in enhancing territorial space planning in coal mining subsidence areas with high groundwater levels. Full article

Crop residue management and soil tillage (CRM and ST) are key steps in agricultural production. The effects of different CRM and ST modes on the quality of seedbed, seeding, and harvest yield are not well determined. In this study, the system of maize (Zea mays L.)–soybean (Glycine max (L.) Merr) rotation under ridge-tillage in the semi-arid regions of Northeast China was chosen as the study conditions. Four modes were investigated: deep tillage and seeding (DT and S), stubble field and no-tillage seeding (SF and NTS), three-axis rotary tillage and seeding (TART and S), and shallow rotary tillage and seeding (SRT and S). Results show that the DT and S mode produced the best quality of seedbed and seeding. Among the conservation tillage modes, the SRT and S mode produced the shortest average length of roots and straw, the best uniformity of their distribution in the seedbed, and the highest soybean yield. Both the SRT and S and SF and NTS modes yielded a higher net profit as their cost-effectiveness. When considering only the quality of seedbed and seeding under conservation tillage as a prerequisite, it can be concluded that the SRT and S mode is both advantageous and sustainable. Full article

Volumetric error decoupling is a critical prerequisite for effective error compensation. In this paper, the forward volumetric error model is established using the screw theory. Additionally, the Jacobian matrix based on the product of exponential is derived to construct the linear relationship between the volumetric error and the axis motion and decouple the volumetric error model. To address the limitation of compensation motion, a step-by-step decoupling method is proposed, where attitude and position errors are compensated sequentially. After detecting the actual geometric errors of the grinding machine, the volumetric error can be determined, and the compensation motion commands for each axis are calculated to correct the volumetric error. The simulation result shows that the mean value of the comprehensive error ranges can be reduced from 19.7 μm to 1.8 μm, demonstrating the effectiveness of the proposed method. Full article

The mineralocorticoid receptor (MR), traditionally associated with renal function, has also been identified in various extrarenal tissues, including the heart, brain, and dorsal root ganglion (DRG) neurons in rodents. Previous studies suggest a role for the MR in modulating peripheral nociception, with MR activation in rat DRG neurons by its endogenous ligand, aldosterone. This study aimed to determine whether MR, its protective enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), its endogenous ligand aldosterone, and the aldosterone-synthesizing enzyme CYP11B2 are expressed in human DRG neurons and whether they colocalize with key pain-associated signaling molecules as potential targets for genomic regulation. To this end, we performed mRNA transcript profiling and immunofluorescence confocal microscopy on human and rat DRG tissues. We detected mRNA transcripts for MR, 11β-HSD2, and CYP11B2 in human DRG, alongside transcripts for key thermosensitive and nociceptive markers such as TRPV1, the TTX-resistant sodium channel Nav1.8, and the neuropeptides CGRP and substance P (Tac1). Immunofluorescence analysis revealed substantial colocalization of MR with 11β-HSD2 and CGRP, a marker of unmyelinated C-fibers and thinly myelinated Aδ-fibers, in human DRG. MR immunoreactivity was primarily restricted to small- and medium-diameter neurons, with lower expression in large neurons (>70 µm). Similarly, aldosterone colocalized with CYP11B2 and MR with nociceptive markers including TRPV1, Nav1.8, and TrkA in human DRG. Importantly, functional studies demonstrated that prolonged intrathecal inhibition of aldosterone synthesis within rat DRG neurons, using an aldosterone synthase inhibitor significantly downregulated pain-associated molecules and led to sustained attenuation of inflammation-induced hyperalgesia. Together, these findings identify a conserved peripheral MR signaling axis in humans and highlight its potential as a novel target for pain modulation therapies. Full article

Metformin is one of the most commonly used medications to treat type 2 diabetes. In addition to lowering blood sugar, it can also promote the regeneration of certain organs or tissues. Planarian Dugesia japonica, with its remarkable regenerative capacity, has become an important model organism for studying pharmacology and regenerative medicine. Planarian eyespot regeneration involves precise tissue regeneration via mechanisms like cell proliferation, differentiation, and gene regulation following body damage. Experiments on planarian eyespot regeneration have confirmed that 1 mM metformin significantly promotes regeneration. Through analysis of the regenerating planarian miRNA database and the metformin-treated transcriptome database, combined with target gene prediction by TargetScan, the DjmiR-27b/DjPax6 axis was finally determined as the research focus. qPCR showed that metformin significantly affects the expression levels of DjmiR-27b and DjPax6. DjPax6 was identified as the target gene of DjmiR-27b through dual luciferase reporter gene analysis. Functional experiments revealed that metformin regulates the expression of DjPax6 via DjmiR-27b, thereby influencing the regeneration of planarian eyespots. In situ hybridization showed that both DjmiR-27b and DjPax6 are expressed throughout the entire body. This study reveals the molecular mechanism of metformin regulating planarian regeneration through miRNA, providing further insights into its role in the field of regeneration. Full article

Glucocorticoids (GCs), such as dexamethasone (DEX), are commonly administered to glioblastoma (GBM) patients to control cerebral edema; however, their effects on immune checkpoint regulation in tumor cells remain insufficiently characterized. This study examined the impact of DEX on the expression of programmed death-ligand 1 (PD-L1) and glucocorticoid-induced leucine zipper (GILZ), a downstream effector of glucocorticoid receptor (GR) signaling, in the U87 and U251 glioblastoma cell lines. DEX consistently induced GILZ expression in both models yet elicited divergent effects on PD-L1: suppression in U87 cells and upregulation in U251 cells. In U87 cells, DEX-induced PD-L1 downregulation was accompanied by accelerated cell cycle progression, suggesting a dual impact on tumor immune evasion and proliferation. Mechanistically, GILZ silencing restored ERK phosphorylation and reversed PD-L1 suppression, whereas GILZ overexpression further decreased PD-L1 levels, implicating a GILZ–ERK pathway in the control of PD-L1. These findings uncover a previously unrecognized GR–GILZ–PD-L1 regulatory axis in glioblastoma cells. While these results are based on in vitro models, they provide a rationale for future in vivo studies to determine whether modulation of GILZ may influence immune checkpoint dynamics and therapeutic responsiveness in GBM. Full article

A general algorithm to determine the coupler link geometric loci, such as centrodes, inflection and return circles, as well as circling-point and centering-point curves, is formulated to analyze any type of four-bar linkages with the main target to find all mechanism configurations, in which at least one of the above-mentioned loci degenerates. Thus, different types of four-bar linkages, such as crank-rocker, double-crank, double-rocker and triple-rocker, are classified according to Grashof’s law, in order to distinguish and analyze their corresponding geometric loci. In particular, the proposed algorithm is based on four diagrams of the angular velocity ratios versus the mechanism driving angle, which consider the links pairs of input/output, input/coupler, and output/coupler, along with those of coupler/input and coupler/output for their relative motion. These diagrams allow the determination of all mechanism configurations according to Freudenstein’s theorems, where the aforementioned geometric loci degenerate into straight lines, including the line at infinity, ϕ-curves, and/or equilateral hyperbolas. This algorithm has been implemented in Matlab in order to run several examples regarding different four-bar linkages, according to Grashof’s law, and analyzing the degenerate forms of their inflection and return circles, as well as the circling-point and centering-point curves, that are also validated by using the collineation axis. Full article

Gait evaluation approaches using small, lightweight inertial sensors have recently been developed, offering improvements in terms of both portability and usability. However, accelerometer outputs include both the acceleration that is generated by human motion and gravitational acceleration, which changes along with the posture of the body part to which the sensor is attached. This study presents a gait analysis method that uses the gravitational, centrifugal, tangential, and translational accelerations obtained from sensors attached to the lower legs. In this method, each sensor pose is sequentially estimated using sensor fusion to combine data obtained from a three-axis gyroscope, a three-axis accelerometer, and a three-axis magnetometer. The estimated sensor pose is then used to calculate the gravitational acceleration that is included in each axis of the sensor coordinate system. The centrifugal and tangential accelerations are determined from the gyroscope output. The translational acceleration is then obtained by subtracting the centrifugal, tangential, and gravitational accelerations from the accelerometer output. As a result, the acceleration components contained in the outputs of the accelerometers attached to the lower legs are provided. As only the acceleration components caused by walking motion are captured, thus reflecting their characteristics, it is expected that the developed method can be used for gait evaluation. Full article

In order to investigate the infection status of Cryptosporidium in O. curzoniae and B. grunniens in Zoige County, Sichuan Province, fecal samples from B. grunniens and gastrointestinal contents from captured O. curzoniae were collected between March and December 2023 from five townships (Dazhasi, Axi, Hongxing, Tangke, and Maixi). Genomic DNA was extracted, and nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium was performed. PCR-positive products were sequenced, trimmed, aligned, and subjected to phylogenetic analysis to determine species and genotypes. A total of 242 samples were obtained, of which 20 were Cryptosporidium SSU rRNA-positive, yielding an overall detection rate of 8.3% (20/242). The detection rates of O. curzoniae and B. grunniens were 7.0% (8/114) and 9.4% (12/128), respectively. Among the five sampling sites, Maixi town exhibited the highest detection rate (32.4%, 11/44), followed by Hongxing town (15.2%, 7/46) and Tangke town (4.6%, 2/44). Phylogenetic analysis detected an unidentified Cryptosporidium sp. in O. curzoniae, while C. bovis (n = 10) and C. ryanae (n = 2) were detected in B. grunniens. These findings demonstrate that Cryptosporidium infections are present in both O. curzoniae and B. grunniens in Zoige County, with notable differences in infection rates and species composition. Continued surveillance of Cryptosporidium in local livestock and wildlife is warranted to provide critical data for regional public health management. Full article