Search Results (68)

This study focuses on optimizing cruciform specimen configurations for the biaxial tensile testing of soft composite materials used in the aerospace industry under conditions of large deformation. A comprehensive evaluation system based on stress–strain uniformity and load transfer efficiency was established, and the stability of these metrics during the tensile process was analyzed. Using finite element simulation and multi-parameter analysis, the main parameter set affecting specimen performance was identified. The influence of different parameters on stress–strain uniformity and load transfer efficiency was investigated. Based on the optimization criteria, an optimized planar cross-shaped specimen configuration was developed. This configuration demonstrated excellent performance stability during deformation, with final stress uniformity error controlled to within 2.2%. The final strain uniformity error was maintained at 2.9%. The fluctuation range of load transfer efficiency did not exceed 1.5%. This study provides guidelines for designing specimens for large deformation testing of soft composite materials and can be used as a reference for future work on optimizing specimens. Full article

This study addresses a critical gap in blast-resistant design by investigating the influence of axial compression ratio—a previously underexplored parameter—on the dynamic response of reinforced concrete (RC) shear walls under close-in explosions. While existing research has focused on conventional loading scenarios, the interplay between axial compression and blast effects remains poorly understood, despite its practical significance for structural safety in high-risk environments. Through a combined experimental and numerical approach, three half-scale RC shear walls were tested under blast loading, complemented by simulations analyzing key parameters (aspect ratio, axial compression ratio, boundary conditions, and charge weight). The results demonstrate that a moderate axial compression ratio (around 0.3) enhances structural stiffness and reduces displacement, effectively helping to control wall damage. Boundary conditions were also found to affect failure modes: walls with stiffer end restraints exhibited reduced deformation but more brittle cracking. Lower aspect ratios (i.e., wider walls) improved blast resistance, and peak displacement progressively increased with the charge weight. These findings provide actionable insights for optimizing RC shear wall design in blast-prone infrastructures, balancing ductility and load capacity. By linking theoretical analysis to practical design criteria, this study advances blast-resistant engineering solutions. Full article

Geotechnical slope failures—often precursors to catastrophic landslides and collapses—pose significant risks to mining operations and regional socioeconomic stability. Focusing on the Jiangte Xikeng lithium open-pit mine, this study integrates field reconnaissance, laboratory testing, and multi-physics numerical modeling to elucidate the mechanisms governing slope stability. Geological surveys and core analyses reveal a predominantly granite lithostratigraphy, bisected by two principal fault systems: the NE-striking F01 and the NNE-oriented F02. Advanced three-dimensional finite element simulations—accounting for gravitational loading, hydrogeological processes, dynamic blasting stresses, and extreme rainfall events—demonstrate that strain localizes at slope crests, with maximum displacements reaching 195.7 mm under blasting conditions. They indicate that differentiated slope angles of 42° for intact granite versus 27° for fractured zones are required for optimal stability, and that the integration of fault-controlled instability criteria, a coupled hydro-mechanical-blasting interaction model, and zonal design protocols for heterogeneous rock masses provides both operational guidelines for hazard mitigation and theoretical insights into excavation-induced slope deformations in complex metallogenic environments. Full article

Background: Individuals with maxillofacial deformities are concerned not only with their facial appearance but also experience dysfunctions of the stomatognathic system, including mastication, swallowing, speech, and breathing. These impairments may lead to negative psychological responses and a reduced quality of life. Aim: The aim of this study was to assess the quality of life and analyse reported dysfunctions of the stomatognathic system in orthognathic patients prior to surgical intervention. Material and methods: The study group (SG) comprised 63 patients with maxillofacial deformities scheduled for orthognathic surgery. The control group (CG) consisted of 70 patients with malocclusions undergoing orthodontic treatment who did not meet the criteria for surgical intervention. Quality of life was assessed in all participants using the Orthognathic Quality of Life Questionnaire (OQLQ), along with a self-reported questionnaire evaluating the presence of stomatognathic system dysfunctions (SS). Results: Significant differences were observed between the study groups regarding all quality-of-life indicators for orthodontic and orthognathic patients. Patients in the SG more frequently reported difficulties in the specified stomatognathic system functions compared to those in the CG. No statistically significant differences were found between SG patients with Class II and Class III malocclusions in terms of OQLQ scores or the frequency of reported SS dysfunctions. Regarding sex differences, women reported a lower overall quality of life and scored lower in social dimensions related to facial deformity and aesthetics compared to men. No significant correlations were observed between the age of orthognathic patients and quality-of-life assessment. Conclusions 1. Orthognathic patients exhibit a poorer quality of life and a higher prevalence of stomatognathic system dysfunctions compared to patients with malocclusions who do not require surgery. The type of skeletal deformity in surgical patients does not influence quality of life or the frequency of stomatognathic dysfunctions. 2. Unlike age, the patient’s sex is a significant factor in the quality of life before orthognathic surgery. Full article

Background/Objectives: Arthroscopy and arthrocentesis are routinely performed for temporomandibular joint (TMJ) disorders, but high-quality evidence regarding their efficacy relative to each other is scarce. The current study, as part of an ongoing randomized controlled trial, aimed to compare office-based arthroscopic lysis and lavage with arthrocentesis for TMJ pain and dysfunction. Methods: Adults (≥18 years old) referred to a tertiary care hospital with TMJ arthralgia were included. The exclusion criteria comprised systemic rheumatic disease, connective tissue disease, bony ankylosis, congenital or acquired dentofacial deformities, a history of significant jaw trauma, or systemic illnesses. The primary outcome was joint pain during mandibular movement/function (visual analog scale (VAS); 0–100 mm). The secondary outcomes included pain at rest (VAS), maximum mouth opening (mm), maximum mouth opening without increased pain (mm), protrusive and lateral movements (mm), joint noises (absent/present), and mandibular function (mandibular function impairment questionnaire score). The outcomes were registered at baseline and 3-, 6-, and 12-month follow-ups. Linear mixed models and mixed-effects logistic regressions were utilized to evaluate the effects of interventions on the repeated outcome measurements. Results: Twenty subjects were randomly allocated to office-based arthroscopic lysis and lavage (n = 10) or arthrocentesis (n = 10). Multivariable mixed-effects models showed significantly higher pain scores during mandibular movement/function in the arthrocentesis group compared with arthroscopy (22.42 mm (95% CI: 5.28 to 39.57); p = 0.011). The secondary outcomes were not significantly different between the interventions. Conclusions: The preliminary results show the superiority of office-based arthroscopy over arthrocentesis in reducing pain during mandibular movement/function over a follow-up period of 1 year while showing no differences between interventions regarding other study outcomes. Full article

Thermoplastic injection molding is a widely used process for producing complex three-dimensional plastic parts with tight dimensional tolerances. A key determinant of part quality is the switchover point—the transition from velocity-controlled filling to pressure-controlled packing. This transition affects critical product attributes, such as d imensional accuracy, weight consistency, and surface finish. Precise control of the switchover point enhances process stability, robustness, and adaptability. This review consolidates recent advancements in switchover methods and adaptive control techniques. Improvements in traditional methods include the use of pressure gradient detection to mitigate viscosity variations and adaptive control to refine stroke- and time-dependent switchovers. In addition, deformation-based strategies detect the mold-opening force associated with cavity pressure through clamping force, mold separation, or tie-bar elongation. The integration of machine learning and feature extraction techniques enables the real-time adjustment of the switchover point by mapping relationships between process parameters and quality criteria. In addition, ultrasonic sensors provide non-invasive melt front detection, reducing the risk of mold damage. Real-time simulations, updated through nozzle pressure feedback, complement these methods to achieve precise switchover timing. This review also identifies persistent challenges, such as sensitivity to material properties, machine wear, and environmental conditions, and it explores future directions for improving the accuracy and adaptability of switchover control in modern injection molding processes. Full article

Breast reconstruction after mastectomy improves the quality of life for many patients with breast cancer. There is uncertainty regarding eligibility criteria for reconstruction, timing (immediate or delayed—with or without radiotherapy), outcomes of nipple-sparing compared to skin-sparing mastectomy, selection criteria and surgical factors influencing outcomes of nipple-sparing mastectomy, prepectoral versus subpectoral implants, use of acellular dermal matrix, and use of autologous fat grafting. We conducted a systematic review of these topics to be used as the evidence base for an updated clinical practice guideline on breast reconstruction for Ontario Health (Cancer Care Ontario). The protocol was registered on PROSPERO, CRD42023409083. Medline, Embase, and Cochrane databases were searched until August 2024, and 229 primary studies met the inclusion criteria. Most studies were retrospective non-randomized comparative studies; 5 randomized controlled trials were included. Results suggest nipple-sparing mastectomy is oncologically safe, provided there is no clinical, radiological, or pathological indication of nipple-areolar complex involvement. Surgical factors, including incision location, may affect rates of complications such as necrosis. Both immediate and delayed reconstruction have similar long-term outcomes; however, immediate reconstruction may result in better short to medium-term quality of life. Evidence on whether radiotherapy should modify the timing of initial reconstruction or expander-implant exchange was very limited; studies delayed reconstruction after radiotherapy by at least 3 months and, more commonly, at least 6 months to avoid the period of acute radiation injury. Radiation after immediate reconstruction is a reasonable option. Surgical complications are similar between prepectoral and dual-plane or subpectoral reconstruction; prepectoral placement may give a better quality of life due to lower rates of long-term complications such as pain and animation deformity. Autologous fat grafting was found to be oncologically safe; its use may improve quality of life and aesthetic results. Full article

Performance-based seismic design (PBD) has emerged as a key approach for rationalizing prescriptive code provisions and improving the explicit assessment of structural performance. In Chile, where reinforced concrete shear wall buildings are the predominant structural typology, evaluating their seismic response beyond traditional linear methodologies is crucial. This study assesses the seismic performance of a representative Chilean shear wall residential building using the ACHISINA manual’s performance-based seismic design framework. A nonlinear static (pushover) analysis is performed to verify compliance with prescribed design criteria, incorporating capacity design principles and a moment envelope approach to prevent premature yielding in upper stories. The results confirm that the building meets the performance objectives for both Immediate Occupancy and Additional Deformation Capacity limit states. The application of capacity design effectively controls shear demand, preventing brittle failure, while the flexural design ensures the formation of the yielding mechanism (plastic hinge) at the intended critical section. Additionally, the study highlights the limitations of pushover analysis in capturing higher-mode effects and recommends complementary nonlinear time-history analysis (NLTHA) for a more comprehensive assessment. The computed response reduction factors exceed those used in the prescriptive design, suggesting a conservatively safe approach in current Chilean practice. This research reinforces the need to integrate performance-based methodologies into Chilean seismic design regulations, particularly for shear wall structures. It provides valuable insights into the advantages and limitations of current design practices and proposes improvements for future applications. Full article

Secondary pre-tightening of clamping cable joints can effectively improve the load-bearing performance of U-shaped steel supports. However, the underlying mechanism of secondary pre-tightening has remained a critical knowledge gap in ground control engineering, and its design still relies on empirical approaches without theoretical guidance. To address these challenges, this study proposes a novel mechanistic framework integrating mathematical modelling, experimental validation, and parametric analysis. Specifically, a first-principle-based mathematical expression for the slip resistance of clamping cable joints under secondary pre-tightening was derived, explicitly incorporating the effects of bolt torque and interfacial friction; and a dual-phase experimental protocol combining axial compression tests and numerical simulations was developed to systematically quantify the impacts of initial pre-tightening torque, secondary pre-tightening torque (T₂), and the timing of secondary pre-tightening (u/u_max). Three groundbreaking thresholds were identified, as follows: critical initial pre-tightening torque (T₁ > 250 N·m) beyond which secondary pre-tightening becomes ineffective (<5% improvement); minimum effective secondary pre-tightening torque (T₂/T₁ > 1) for significant load-bearing enhancement; and the optimal activation window (u/u_max < 50%) balancing capacity gain (<10%) and deformation control. These findings establish the first quantitative design criteria for secondary pre-tightening applications, transitioning from empirical practice to mechanics-driven optimization. Full article

In hub-motor electric vehicles (HMEVs), performance is adversely affected by the mechanical-electromagnetic coupling effect arising from deformations of the air gap in the Permanent Magnet Brushless Direct Current Motor (PM BLDC), which are exacerbated by varying road conditions. In this paper, a Model Predictive Control (MPC) strategy for HMEVs equipped with air suspension (AS) is introduced to enhance ride comfort. Firstly, an 18-degree of freedom (DOF) full-vehicle model incorporating unbalanced electromagnetic forces (UEMFs) induced by motor eccentricities is developed and experimentally validated. Additionally, a Minimum Model Error Extended Kalman Filter (MME-EKF) observer is designed to estimate unmeasurable state variables and account for errors resulting from sprung mass variations. To further improve vehicle performance, the MPC optimization objective is formulated by considering the suspension damping force and dynamic displacement constraints, solving for the optimal suspension force within a rolling time domain. Simulation results demonstrate that the proposed MPC approach significantly improves ride comfort, effectively mitigates coupling effects in hub driving motors, and ensures that suspension dynamic stroke adheres to safety criteria. Comparative analyses indicate that the MPC controller outperforms conventional PID control, achieving substantial reductions of approximately 41.59% in sprung mass vertical acceleration, 14.29% in motor eccentricity, 1.78% in tire dynamic load, 17.65% in roll angular acceleration, and 16.67% in pitch angular acceleration. Full article

Background and objectives: Idiopathic scoliosis is a three-dimensional spinal deformity characterized by a lateral curvature exceeding 10 degrees in the frontal plane accompanied by vertebral rotation in the transverse plane. Despite extensive research on genetic and neurological factors, its etiology is uncertain. This prospective observational study aims to investigate the relation between the primitive reflexes, specifically, the asymmetric tonic neck reflex (ATNR), symmetric tonic neck reflex (STNR), and spinal Galant reflex (SGR), which play key roles in early motor development and postural control and the severity of idiopathic scoliosis (measured via the Cobb angle and the Nash–Moe rotational quota. Additionally, the study evaluated whether the retention of primitive reflexes correlates with increased progression risk over 12 months of conservative treatment. Materials and Methods: Our study cohort included 162 patients, aged 7–19 years, diagnosed with idiopathic scoliosis, who underwent clinical examination and assessment of retained primitive reflexes using standardized grading systems. Results: A total of 162 patients (95 girls, 67 boys; mean age: 12.73 ± 2.74 years) met the inclusion criteria. In 73.5% of the cases, scoliosis was detected, with the majority occurring in the dorsal region (40.1%). The mean initial Cobb angle was 13.49° ± 7.14°, with no significant change after 12 months of conservative treatment (p = 0.584). Nash–Moe rotation scores were 1 in 52.5% and 2 in 22% of the cases. Retention of the following primitive reflexes were identified at baseline: Moro (19.1%), ATNR (38.3%), STNR (44.4%), and GSR (27.8%). GSR retention significantly correlated with the Cobb angle (p = 0.011; R = 0.233). All the reflex scores decreased significantly after 12 months, but no correlation existed between the retained reflexes and scoliosis progression. Patients with a history of quadrupedal locomotion had significantly lower ATNR (p = 0.002), STNR (p < 0.001), and GSR (p = 0.017) retention. Conclusions: These findings suggest that primitive reflex testing could serve as an early screening tool in scoliosis risk stratification, being a cost-effective, non-invasive instrument for identifying at-risk children before clinically significant deformity develops. Full article

Background: This systematic review examines the clinical presentations and prevalence of scapulohumeral periarthritis (SP) by synthesizing the relevant literature from open-access articles from international databases (Medline, Pedro, and EBSCO). Methods: Keywords guiding the review included ‘scapulohumeral periarthritis’, ‘clinical forms’, ‘incidence’, ‘impingement syndrome, ‘calcifying tendinitis’, ‘bicipital tendonitis’, ‘shoulder bursitis’, ‘adhesive capsulitis or frozen shoulder’, ‘rotator cuff tears’, ‘functional assessment’, and ‘clinical trials’. Eligible studies included randomized controlled trials, nonrandomized controlled trials, cross-sectional studies, and review articles published between 1972 and 2024. Results: Our screening identified 2481 initial articles, of which 621 were further reviewed for eligibility resulting in 107 articles that met the relevance criteria. The findings highlight six distinct clinical forms of SP, such as partial rotator cuff tears and calcific tendinitis, each characterized by specific pathological features and prevalence patterns. Key factors contributing to SP include injuries, scapular instability, acromion deformities, and degenerative rotator cuff changes. Functional assessments, including the Neer, Hawkins, Pain Arc, and Yocum tests, demonstrated diagnostic value in distinguishing SP from other shoulder conditions. Conclusions: By comprehensively analyzing the clinical forms, functional assessment methods, and prevalent lesions of SP, functional testing can improve early diagnosis and guide personalized physiotherapy protocols for optimal rehabilitation in the physiotherapist’s practice. Full article

Background and Objectives: Valgus-impacted femoral neck fractures (OTA 31B1.1 and 31B1.2) are considered stable fractures with favorable outcomes compared to displaced fractures. However, complications such as femoral neck shortening, screw sliding, and suboptimal recovery can occur, particularly in severe deformities. This study evaluated the outcomes of a sequential fixation technique using short-threaded screws followed by long-threaded screws. Materials and Methods: This prospective study included 135 patients aged 60 years or older with valgus-impacted femoral neck fractures (OTA 31B1.1 and 31B1.2) treated between March 2017 and February 2021. Patients were divided into two groups: those treated solely with short-threaded screws (the control group) and those treated using a sequential fixation technique involving initial compression with short-threaded screws followed by stabilization with long-threaded screws. Exclusion criteria included follow-up < 12 months, pathological fractures, high-energy trauma, or periprosthetic fractures. Clinical outcomes, including the Harris Hip Score (HHS), and radiological parameters, such as screw sliding distance (SDS) and fixation failure, were analyzed. Multivariate regression identified predictors of outcomes to assess the effectiveness of the sequential fixation technique. Results: The mean follow-up was 38.3 months. Multivariate regression revealed that posterior tilt > 15° (β = 2.944, p < 0.001) and the use of long-threaded screws (β = −1.906, p < 0.001) were significant predictors of reduced SDS. Posterior tilt > 15° (OR 15.085, p = 0.002), valgus tilt > 15° (OR 28.616, p = 0.002), and bone mineral density (OR 0.285, p = 0.005) were predictors of fixation failure, while long-threaded screws significantly reduced fixation failure risk (OR 0.062, p = 0.005). Conclusions: The sequential use of short-threaded screws for compression, followed by long-threaded screws for stabilization, effectively reduced screw sliding and fixation failure while improving functional and radiological outcomes. This technique shows promise as an effective treatment for valgus-impacted femoral neck fractures. Full article

Parkinson’s disease is the second most common neurodegenerative disease worldwide, characterized by bradykinesia, rigidity, tremor, and postural instability. These symptoms often lead to significant postural deformities and an increased risk of falls, severely impacting the quality of life. Conventional rehabilitation methods have shown benefits, but recent advancements suggest that virtual reality (VR) could offer a promising alternative. This scoping review aims to analyze the current literature to evaluate the effectiveness of VR in the postural rehabilitation of patients with PD. A scientific literature search was performed using the following databases: PubMed, PEDro, Cochrane, and Google Scholar, focusing on randomized controlled trials (RCTs) published in English. Our selection criteria included studies that compared VR-based rehabilitation to traditional methods regarding posture-related outcomes. We identified and analyzed nine RCTs that met our inclusion criteria. The results consistently demonstrated that VR-based rehabilitation leads to greater improvements in balance and gait compared to conventional therapy. Key findings include significant enhancements in balance confidence and postural control and a reduction in fall rates. The superior efficacy of VR-based rehabilitation can be attributed to its engaging and immersive nature, which enhances patient motivation and adherence to therapy. VR allows for precise, repeatable training scenarios tailored to individual patient needs, providing a safe environment to practice and improve motor skills. In conclusion, VR-based rehabilitation represents an innovative approach with substantial potential to improve the quality of life for PD patients. However, limitations such as small sample sizes and short intervention durations in existing studies highlight the need for larger multicenter trials with longer follow-up periods to confirm these findings. Full article

Background: Deformities of the foot represent a significant clinical problem. Toe separators constitute an available tool used in various forms of conservative treatment, primarily used for the correction of hallux valgus, but also for improvement in the condition of neurological patients, e.g., after a stroke, or to treat dermatological problems. The goal of this systematic review is to critically assess the current scientific literature on the application of toe separators as a therapeutic intervention in physiotherapy. Methods: A systematic search was conducted across several electronic databases, such as PubMed, Science Direct, and Web of Science. The review included randomized controlled trials, quasi-experimental studies, and observational studies that explored the use of toe separators in physiotherapeutic interventions. Two independent reviewers evaluated all search results to determine eligible studies and assess their methodological quality. Results: A total of 1020 studies were found through the database search. Out of these, 10 studies met the inclusion criteria and were incorporated into the review. The sample sizes of the selected studies varied from 9 to 90 participants. In the majority of the studies, the methodological quality was not mentioned, and a frequent lack of information was noted. Based on a literature analysis, separators were primarily used as a tool for the correction of hallux valgus, but there are also promising results for use in neurology and dermatology as well as affecting the lower leg muscles during gait. Conclusions: The use of toe separators can be a valuable tool for the conservative treatment of hallux valgus and the associated deformities. The research so far varies in describing the type, material, and method of the application of the separators. Studies showed a variety of applications as well as variation in the use of materials. Further research is needed to establish the effectiveness of toe separators in foot disorders more precisely. Full article