Search Results (49,988)

Patients with chronic obstructive pulmonary disease (COPD) commonly experience impaired lung function, reduced exercise tolerance, and respiratory muscle weakness. Owing to the unique properties of the aquatic environment, water-based exercise may provide rehabilitation benefits that differ from those of traditional land-based exercise. Objective: This systematic review and meta-analysis aimed to compare the effects of water-based versus land-based exercise on lung function, exercise capacity, and respiratory muscle function in patients with COPD, thereby providing evidence to inform the optimization of pulmonary rehabilitation exercise modalities. Methods: PubMed, Web of Science, CNKI, and other databases were systematically searched to identify randomized controlled trials comparing water-based and land-based exercise interventions in adults with COPD. Primary outcomes included lung function (FEV₁% predicted and FEV₁/FVC), exercise capacity (six-minute walk distance, 6MWD), respiratory muscle strength (maximal inspiratory pressure (MIP]) and maximal expiratory pressure (MEP). Meta-analyses were performed using Stata 17.0. Results: A total of 14 RCTs were included. Meta-analysis showed that, compared with land-based exercise, water-based exercise significantly improved FEV₁% predicted (WMD = 3.33, 95% CI: 0.02–6.64) and FEV₁/FVC (WMD = 4.00, 95% CI: 1.27–6.73). Regarding exercise capacity, water-based exercise significantly increased 6MWD (WMD = 47.81 m, 95% CI: 20.19–75.44), with more pronounced improvements observed in short-term interventions (≤8 weeks). Respiratory muscle function analyses demonstrated significant improvements in MIP (WMD = 14.22 cmH₂O, 95% CI: 7.75–20.69) and MEP (WMD = 14.40 cmH₂O, 95% CI: 4.92–23.89). Conclusions: Compared with land-based exercise, water-based exercise demonstrates consistent advantages in improving exercise capacity and respiratory muscle function in patients with COPD and shows additional benefits for lung function indices. Therefore, water-based exercise may serve as a valuable adjunct to land-based training within pulmonary rehabilitation programs. Full article

The application of fully recycled aggregate concrete (FRAC) promotes sustainable construction, but its mechanical properties are often unstable due to the high absorption and variability of recycled aggregates. This study investigates the effect of saturation degrees of recycled coarse aggregate (RCA) and recycled fine aggregate (RFA) on FRAC’s mechanical performance and failure mechanisms. Results show that optimal strength is achieved at 70% RCA and 25% RFA saturation. Reducing RFA saturation from 100% to 25% increases compressive strength by 28.8% and tensile strength by 34.6%. RFA saturation has a greater influence than sand ratio or superplasticizer dosage, second only to water–cement ratio. Analysis indicates that excessive saturation leads to pores and microcracks in the interfacial transition zone, weakening bonding. A multiple linear regression model based on recycled aggregate saturation accurately predicts FRAC properties, supporting optimized use of recycled materials and cleaner construction practices. Full article

Open-hole compression (OHC) tests were carried out on non-crimp fabric (NCF) laminates with varied open-hole orientation (angle to the loading direction) and inter-hole spacing. Failure modes were documented by scanning electron microscopy (SEM), and the compressive strength was quantified. Finite element simulations in Abaqus were developed to replicate the tests, establishing a progressive-damage model for open-hole laminates under compression. Intralaminar failure was described using the three-dimensional Hashin failure criterion and a modified matrix compression criterion incorporating shear coupling effects, while interlaminar delamination was modeled with cohesive elements, enabling the simulation of damage initiation, growth, delamination, and final collapse. The results show that hole orientation and spacing have a pronounced effect on open-hole compression (OHC) strength. A spacing threshold is observed, beyond which further increases in spacing provide little additional benefit. In contrast, the apparent elastic stiffness is essentially insensitive to hole spacing and orientation. The combined intralaminar and interlaminar model successfully reproduces the characteristic mechanical response—linear elasticity followed by catastrophic failure—in good agreement with the experiments. Full article

Hot-forming, as a typical representative forming technology of high-strength steel (HSS), is one of the most effective ways to manufacture structural components for achieving automotive lightweighting goal. In this paper, a newly-developed commercial microalloyed hot-formed steel is selected and its hot-forming is studied by experiments and simulations. The new steel has a wide undercooled austenite region, providing more suitable condition for the manufacturing of one-piece large-sized integrated parts. The high-temperature mechanical behaviors of the investigated steel show that the flow stress obviously decreases with the increase in deformation temperature, and it increases with the increasing strain rate. An integrated component assembly of the rear floor and longitudinal beam is selected as a typical one-piece integrated part when performing the hot-forming simulation to evaluate the formability. The influences of the key process parameters, namely forming velocity and frictional coefficient, on formability are further analyzed. Finally, the Latin Hypercube Sampling (LHS) method is used to generate the parameter combination and the Response Surface Method (RSM) is adopted in optimization. As a result, an optimal process parameter combination is obtained and its predicted result matches the simulated one very well, with a relative error of only 2.57%. The research results of this paper are favorable for understanding the mechanical behaviors of the hot-formed steel at elevated temperatures, improving the formability and providing a reference for the development of large-sized integrated hot-formed parts. Full article

Background/Objectives: Sarcopenia, obesity, and sarcopenic obesity (SO) are common in older adults and may be associated with functional limitations in Basic (BADL) and Instrumental (IADL) Activities of Daily Living. This study aimed to evaluate the association between body composition phenotypes and BADL/IADL limitations among older adults. Methods: A cross-sectional study included 440 community-dwelling adults aged ≥60 years (281 women, 159 men; mean age 74.7 ± 7.8 years). Sarcopenia was diagnosed according to EWGSOP2 criteria, obesity was defined as Percent Body Fat > 42% in women and >30% in men, and SO was classified based on the ESPEN/EASO recommendations. The reference phenotype was ‘non-sarcopenic, non-obese’. Functional status was evaluated using the Katz and Lawton scales, with limitations defined as BADL ≤ 5 and IADL ≤ 26 points, respectively. Multivariate logistic regression was performed to determine associations between body composition phenotypes and BADL/IADL limitations. Results: Over half of the participants (57.1%) had abnormal body composition: 31.6% obesity, 11.4% sarcopenia, and 13.2% SO. Sarcopenic obesity was associated with nearly threefold higher odds of BADL limitations (OR = 2.86; p = 0.003) and 3.7-fold higher odds of IADL limitations (OR = 3.68; p < 0.001), compared to the reference phenotype. Sarcopenia was associated with IADL limitations only in the unadjusted model (OR = 2.44; p = 0.010). Beyond adverse body composition phenotypes, BADL/IADL limitations were also associated with lower muscle strength, multimorbidity, and poorer nutritional status. Conclusions: SO was linked to both BADL and IADL limitations, while sarcopenia was associated only with IADL deficits. Isolated obesity showed no consistent relationship with functional impairment. These findings support prioritizing SO in screening and prevention, although the cross-sectional design precludes causal inference. Full article

The clinical management of myeloid neoplasms increasingly relies on the accurate detection and longitudinal monitoring of disease-defining genetic alterations. Many clinically relevant mutations are often present at very low variant allele frequencies, below the detection limits of conventional approaches routinely used in diagnostic workflows. In recent years, a growing number of ultra-sensitive molecular technologies have been developed to overcome these limitations, enabling the detection of rare variants with unprecedented precision, offering complementary strengths in terms of sensitivity, quantification, throughput, and clinical applicability. This review provides a comprehensive overview of established and emerging ultra-sensitive technologies for the diagnosis and molecular monitoring of myeloid neoplasms, discussing their technical principles, advantages, and limitations. Full article

This paper presents a performance evaluation of IEEE 802.11ax (Wi-Fi 6) networks using a combination of real-world testbed measurements and simulation-based analysis. The paper investigates the combined effect of received signal strength (RSSI), application bitrate, and network topology on video playback delays of 802.11ax. The effect of frequency band and client density on system performance is also investigated. Testbed measurements and field experiments were conducted in indoor environments using dual-band (2.4 GHz and 5 GHz) ad hoc and infrastructure network configurations. OMNeT++ based simulations are conducted to explore scalability by increasing the number of wireless clients. The results obtained show that the infrastructure-based deployments provide more stable video playback than the ad hoc network, particularly under varying RSSI conditions. While the 5 GHz band delivers higher throughput at a short range, the 2.4 GHz band offers improved coverage at reduced system performance. The simulation results further demonstrate significant degradation in throughput and latency as client density increases. To contextualize the observed performance, a baseline comparison with 802.11ac is incorporated, highlighting the relative improvements and remaining limitations of 802.11ax within the evaluated signal and load conditions. The findings provide practical deployment insights for video-centric wireless networks and inform the optimization of next-generation Wi-Fi deployments. Full article

In the era of growing demand for sustainable solutions in construction, increasing attention is being paid to the potential use of waste materials as components of building composites. This article presents the results of a study on the impact of ground polyurethane foam waste on the mechanical properties and durability of cement mortars. The waste, derived from industrial production processes, was used as a partial replacement for fine aggregates in various proportions. The analysis included bulk density, compressive and flexural strengths, water absorption, and resistance to freeze–thaw cycles. The results indicate that adding waste reduces the density of the mortar, which can be advantageous in applications requiring lightweight materials. The most favourable balance of strength retention, density reduction, and frost resistance was observed with a 1% addition, as the mortar maintained good mechanical performance and freeze–thaw durability while achieving reduced weight. Higher waste content (2–3%) led to significant deterioration of the mechanical properties due to increased porosity. All samples exhibited increased strength after 25 freeze–thaw cycles, possibly due to continued hydration under moist low-temperature conditions. The analysis of the microstructure of cement coatings with the addition of polyurethane foam enabled the explanation of the causes of the observed changes in physico-mechanical properties resulting from ageing factors. This study suggests that small amounts of waste can be effectively used to produce lightweight and environmentally friendly construction materials, supporting circular economy practices. Full article

Carbon-enriched concentrates based on shungite ore from rare-metal mining waste were obtained, and their effect on the properties of oil- and fuel-resistant carbon-black-filled rubber used for the production of pressure hoses was investigated. The shungite concentrates were produced by flotation followed by acid activation. A blend of nitrile butadiene rubber and butadiene–α-methylstyrene rubber was used as the elastomeric base. Carbon black was partially replaced with shungite fillers (5–15 phr). The presence of shungite was found to prolong both the scorch time and the optimum cure time of the rubber compounds, likely due to oxide impurities that interfere with the vulcanization activation process. Replacing carbon black with shungite ore and its flotation concentrate in the rubber formulations resulted in a decrease in Mooney viscosity compared to the samples without shungite fillers. Acid-activated shungite concentrate at contents above 5 phr increases the viscosity of the rubber compound. It was found that acid-activated shungite concentrate provides high tensile strength and excellent thermo-oxidative stability of the rubber, whereas the use of shungite ore above 5 phr reduces the tensile strength and causes significant changes in tensile properties upon thermo-oxidation. When exposed in oil, rubbers containing shungite fillers retain their mechanical properties, with the best resistance in hydrocarbon media observed for the rubber filled with acid-activated shungite concentrate. Full article

Polymetallic nodules enriched in Mn, Ni, Cu, Co, and other metals may be one of the first seabed mineral resources to be exploited. Although optical imagery is crucial for resource evaluation, semi-buried nodules are frequently overlooked. To address this, we propose a framework that integrates the elliptic approximation method (EAM) and the contour interweaving method (CIM) to reconstruct three types of semi-buried nodules segmented by U-Net: edge-buried, partition-buried, and almost-completely-buried. This strategy introduced a decision-making mechanism based on category fusion, which significantly enhanced the robustness and practicality of the reconstruction. Performance was assessed using four metrics: area ratio, absolute percentage change, intersection-over-union, and Chamfer distance. Among 1785 samples, the EAM recovered up to 41.8% of lost area, which substantially improved the minimum values of area ratio and intersection-over-union, and it performed well on almost-completely-buried nodules. The CIM achieved median area ratio and intersection-over-union values of 99.37% and 93.36%, respectively, and excelled in edge-buried and partition-buried types. Fusion experiments demonstrated the complementary strengths of both approaches: 23.96% of buried area was recovered in large-scale imagery recognized by U-Net. The proposed framework balances accuracy, adaptability, and computational efficiency, which enables real-time nodule identification on platforms with limited resources such as autonomous underwater vehicles. This could provide more direct support for resource evaluation and mining applications. Full article

With the development of novel production routes enabling near-zero emissions from lime manufacturing, the use of lime as a carbon-sequestering component in cementitious materials has attracted increasing attention. To address the intrinsically low early-age strength of lime-enriched binders (LP), this study investigates the modification effect of polyvinyl alcohol (PVA) on LP, with systematic comparisons to ordinary Portland cement (PO) and pure lime systems (LE). The results indicate that, in terms of mechanical performance, the incorporation of PVA significantly enhances the early-age strength of LP, particularly the flexural strength, which increases by 119.3%. In contrast, the strength of PO shows a certain degree of reduction after PVA addition. Regarding carbon uptake performance, the CO₂ sequestration capacity of PO and LE increases by 16.8% and 16.9%, respectively, whereas that of LP slightly decreases by 5.5%. From the hydration perspective, both the heat release rate and cumulative heat of PO and LP are reduced after PVA incorporation. Combined with microstructural analysis, the mechanical enhancement of LP induced by PVA is mainly attributed to the polymer film-forming effect, which compensates for the negative impact caused by the inhibition of hydration. Full article

Background/Objectives: Quadriceps arthrogenic muscle inhibition (AMI) represents a key impairment following anterior cruciate ligament reconstruction (ACLR), contributing to quadriceps weakness. Although transcutaneous electrical nerve stimulation (TENS) and percutaneous electrical nerve stimulation (PENS) have been primarily investigated for analgesia, their effects on quadriceps strength in the early postoperative period remain underexplored. Methods: This study describes a single-blinded, parallel-group randomized controlled trial investigating the short-term effects of a single high-frequency TENS session and a novel long-term potentiation (LTP) PENS protocol on quadriceps strength and related clinical outcomes after ACLR. Fifty-four participants will be randomly allocated using block randomization in a 1:1:1 ratio to one of three groups: a control group (conventional post-ACLR rehabilitation only), a TENS group (conventional rehabilitation plus a single high-frequency TENS session), or a PENS group (conventional rehabilitation plus a single LTP PENS session). Participants will receive neuromodulatory intervention during the sixth postoperative week. The LTP PENS protocol consists of five 5 s stimulation bursts at 100 Hz and 250 μs pulse width and has only been investigated once in patients with upper limb pathology, underscoring its novelty in a postoperative setting. Results: The primary outcome is quadriceps maximal voluntary isometric contraction, selected as a clinically relevant surrogate of quadriceps activation deficits associated with AMI. Secondary outcomes include pain intensity, pressure pain threshold, knee range of motion, thigh muscle perimeter, knee effusion and swelling, and self-reported function and knee-related quality of life. Outcomes will be assessed at baseline, immediately post-treatment, and 1 and 7 days post-intervention by a blinded assessor. Full article

Background and Objectives: This study compared functional performance, gait performance, and dynamic balance between Coronal Plane Alignment of the Knee (CPAK) Type I and Type II patients undergoing unilateral total knee arthroplasty (TKA). Materials and Methods: We included 162 consecutive patients scheduled for unilateral TKA between January 2022 and August 2025. Patients were classified according to CPAK type; 42 were Type I and 33 were Type II. Preoperative assessments included demographic data, Korean Knee Score, and WOMAC. Functional performance was evaluated using the Timed Up and Go (TUG) test and the 4 m walk test. Isokinetic knee extensor and flexor strength (60°/s), hip abductor strength, and bilateral thigh circumferences measured 5 cm and 15 cm proximal to the patella were assessed. Dynamic balance asymmetry was evaluated using the POSTUROMED device. Inter-limb differences were calculated by comparing the operated and non-operated limbs. Results: No significant between-group differences were observed in clinical scores, knee extensor, or flexor strength deficits, hip abductor strength deficits, or thigh circumference differences. However, CPAK Type II patients demonstrated significantly better functional performance, with faster TUG (p = 0.014) and 4 m walk test times (p = 0.022). Dynamic balance outcomes were also significantly better in the Type II group (p = 0.042). Conclusions: Despite similar patient-reported clinical scores and muscle strength, patients with the CPAK Type II phenotype exhibited superior gait performance and dynamic balance compared with those with Type I following unilateral TKA. Full article

Ultra-high-performance concrete (UHPC) is a sophisticated construction material known for its exceptional strength and durability. Conventional UHPC generally self-consolidates, which makes it unsuitable for roof and bridge deck rehabilitation applications due to its thin layers and inclined surfaces. UHPC overlay construction generally requires a highly thixotropic material that responds well to vibration and remains stable on slopes. Despite the complex rheological properties of thixotropic UHPC, there are limited testing methods for effectively assessing the workability of overlay mixes. Therefore, this paper provides a comprehensive evaluation of the workability of overlay UHPC using existing and newly developed tests. Besides the commonly used static and dynamic flow tests, this study introduces Patting Response (PR) and Vibration-Slope Stability (VSS) tests, designed to evaluate different qualities of UHPC overlay mixtures. Seven groups of mixtures with varying binder content, water-to-binder ratio (w/b), fiber reinforcement, and admixture dosages were prepared and tested. A lab-scale sloped slab was constructed to validate the buildability of the most promising mixtures. These tests and mixtures support effective overlay solutions for roof slab and bridge deck repairs, providing protection against infrastructure deterioration and improving overall performance by introducing a dense, durable UHPC overlay. Results indicate that mixtures with static flow below 6 in. and dynamic flow between 7 and 8 in. consistently passed both PR and VSS tests, demonstrating stable vibration response and slope retention. The constructability evaluation confirmed the effectiveness of the new testing methods. Additionally, the correlation between different tests, particularly flow and VSS, was examined. Recommendations for appropriate ranges for various workability tests were established based on the performance of the developed mixtures. The proposed static and dynamic flow ranges are performance-based and are expected to be broadly applicable to thixotropic UHPC overlay systems exhibiting comparable workability and rheological behavior under vibration and sloped placement conditions. Overall, these tests and thixotropic UHPC mixtures facilitate effective repair of roof slabs and bridge decks, providing overlay protection against deterioration and potentially enhancing structural capacity through composite behavior. Full article

The reliability of high-strength bolted connections is critical to the safety of large-scale engineering structures. This study proposes a non-contact quantitative method for detecting bolt loosening based on the self-magnetic flux leakage (SMFL) effect. Systematic experiments were carried out on M14-12.9 bolts, using nine independent specimens tested under six torque levels, to reveal the intrinsic relationship between bolt preload and the “magnetic valley” feature of the surface leakage field. For quantitative evaluation, the absolute value of the differential peak magnetic field, |ΔPMF|, is defined as the core feature parameter. The results show that, in the reference specimen group, |ΔPMF| exhibits a pronounced linear relationship with the applied torque (R² > 0.96), and the corresponding linear regression parameters display good consistency across the nine specimens (RSD ≈ 4%). Comparative tests on two additional bolt specifications clarify how bolt strength grade and geometric size influence the detection sensitivity and linearity. To address lift-off effects, measurements on a representative specimen at four lift-off heights were used to construct a simplified bivariate linear compensation model, which significantly reduces lift-off-induced bias within the working range h = 10–16 mm. Finally, a hierarchical diagnostic scheme for bolt loosening that incorporates lift-off compensation is established on the basis of |ΔPMF|, providing a feasible approach for rapid assessment of bolt loosening under complex service conditions. Full article