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Human embryonic bone and joint formation is determined by coordinated differentiation of progenitors in the nascent skeleton. The cell states, epigenetic processes and key regulatory factors that underlie lineage commitment of these cells remain elusive. Here we applied paired transcriptional and epigenetic profiling of approximately 336,000 nucleus droplets and spatial transcriptomics to establish a multi-omic atlas of human embryonic joint and cranium development between 5 and 11 weeks after conception. Using combined modelling of transcriptional and epigenetic data, we characterized regionally distinct limb and cranial osteoprogenitor trajectories across the embryonic skeleton and further described regulatory networks that govern intramembranous and endochondral ossification. Spatial localization of cell clusters in our in situ sequencing data using a new tool, ISS-Patcher, revealed mechanisms of progenitor zonation during bone and joint formation. Through trajectory analysis, we predicted potential non-canonical cellular origins for human chondrocytes from Schwann cells. We also introduce SNP2Cell, a tool to link cell-type-specific regulatory networks to polygenic traits such as osteoarthritis. Using osteolineage trajectories characterized here, we simulated in silico perturbations of genes that cause monogenic craniosynostosis and implicate potential cell states and disease mechanisms. This work forms a detailed and dynamic regulatory atlas of bone and cartilage maturation and advances our fundamental understanding of cell-fate determination in human skeletal development.

This paper presents experimental investigations on the joints of concrete frame beams and columns with 20% coal ash slag replacing cement. The failure mechanism of concrete frame joints with coal ash slag as a cement replacement is examined, focusing on the impacts of two scenarios – concrete with 20% coal ash slag and ordinary concrete – on the failure mode and seismic performance of beam–column joints, as well as the influence of varying concrete strength grade when the coal ash slag content is 20%. The main research variables are the presence of coal ash slag in the concrete and the concrete strength grade. Findings reveal typical failure modes at the beam-end flexural plastic hinge, progressing through stages of initial cracking, yielding, limit and failure. Joints without coal ash slag exhibit 10.3–16.2% higher ductility, while those with 20% coal ash slag show a 14% improvement in bearing capacity. The C50 joint with 20% coal ash slag outperformed the C40 joint in bearing and energy dissipation, with robust hysteretic curves meeting seismic requirements. Thus, replacing 20% of cement with coal ash slag enhances the durability and seismic performance of concrete components. [ABSTRACT FROM AUTHOR]

In this study, a macro joint model was developed to evaluate the progressive collapse resistance of L-shaped columns composed of concrete-filled steel tube (L-CFST) frames, accounting for joint performance. The methods used to calculate the spring stiffness in each part of the macro joint model were derived using the component method and the deformation coordination principle. Additionally, an L-CFST frame model consisting of fibre beam elements and macro joint models was created. For frame models with different parameters, the dynamic response under column removal was analysed; these parameters included the loading condition, connection type, the location of failed columns, the height and number of floors and the span–depth ratio of the steel beams. The macro joint model was found to have high accuracy in predicting progressive collapse resistance. The L-CFST column frames with novel side-plate reinforced connections fully exploited the catenary mechanism and Vierendeel action. All the variables affected the vertical displacement at the position of the failed columns, with the span–depth ratio having the most significant impact. [ABSTRACT FROM AUTHOR]

A new methodology based on the limit analysis upper bound method for the topological optimisation of slopes is presented, to determine geotechnically optimal slope profiles in anisotropic jointed rock masses. The methodology accounts for the effects of discontinuities such as joints, bedding planes, and tension cracks. We applied this methodology to the context of open pit mines, with the goal of achieving geotechnically optimal pitwall profiles. The optimal profiles maximise the Overall Slope Angle (OSA) while maintaining a prescribed Factor of Safety (FoS) and satisfying the geometric constraints imposed by benches and ramps. The method, implemented in the software OptimalSlope, utilises direction-dependent cohesion and internal friction angle parameters to replicate the effect of joints on slope stability. Key inputs include joint orientation, non-persistence, and probability of occurrence. We tested the methodology on a Mexican open pit mine to be excavated into Cretaceous siltstone featuring eight different joint sets and a primary bedding plane. Optimal pitwall profiles were determined for various combinations of bedding dip angles (0°, 15°, 30°, 45°, 60°, 75°, 90°) and mine pitwall orientations (hanging wall, footwall, side walls), considering the three-dimensional kinematics of the joints through anisotropic functions of cohesion and friction angle. Results indicate that the optimal pitwall profiles generally exhibit higher OSA compared to planar profiles with the same FoS, except in one bedding dip direction. Additionally, stability analyses performed using Rocscience Slide2 independently verified the FoS values of the optimal profiles. [ABSTRACT FROM AUTHOR]

AbstractThe low-velocity impact damage tolerance of 3D woven composite joints is investigated by multiscale numerical and experimental methods. Microscale, mesoscale, and macroscale models are developed to analyze the interactions between fibers, matrix, and structures. The microscale fiber, matrix, and interfacial behavior are examined to identify critical failure mechanisms. The mesoscale model focuses on the influence of yarn morphology and interfacial sliding on the damage initiation and propagation paths. At macro scale, the numerical analysis results of the joint have good agreement with the experiments, revealing the impact-induced damage and its influence on post-impact tensile behavior. [ABSTRACT FROM AUTHOR]

Joints are pivotal components in prefabricated station technology, requiring development to meet diverse requirements such as site conditions, safety, stability, operability and waterproofing. CHC joints, while addressing these factors, offer the advantages of easy assembly and clear force transmission. These advantages of CHC joints have been verified in the application of Pingxi station in Shenzhen, China. Furthermore, the mechanical transmission mechanism of CHC joints is novel and distinct from existing joint types. In this study, with the use of experimental methods, further investigation is conducted into the flexural mechanical properties of CHC joints, elucidating their flexural behaviour and failure modes. The findings indicate that the axial force transmission mechanism of CHC joints ensures stable tension transmission under bending moment loads; the flexural stiffness of joints exhibits pronounced non-linearity; and the failure mode of joints resembles that of reinforced concrete beams with adequate reinforcement, demonstrating ductile failure. This research offers valuable insights for the design of CHC joints. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs), particularly exosomes (EXOs) of various skeletal and stem cells, were shown to delay osteoarthritis (OA) progression, and apoptotic bodies (ABs), another EV subtype, of osteoclasts showed osteoanabolic actions and were involved in the osteoclastic-regulation of local bone formation. Moreover, this study demonstrates that microvesicles (MVs) released by osteoclasts displayed potent pro-chondrogenic, pro-osteogenic, and anti-inflammatory activities. These activities were unique to osteoclastic MVs and were not shared by osteoclastic ABs and EXOs or MVs of other cell types. Because chronic synovial inflammation, progressive articular cartilage erosion, abnormal subchondral bone remodeling, and inability to regenerate articular cartilage are key etiologies of OA, we postulate that the foregoing activities of osteoclastic MVs could simultaneously target multiple etiologies of OA and could thereby be an effective therapy for OA. Accordingly, this study sought to assess the feasibility of an osteoclastic MV-based strategy for OA with a mouse tibial plateau injury model of OA. Briefly, tibial plateau injuries were created on the right knees of adult C57BL/6J mice, MVs were intraarticularly injected into the injured joints biweekly, and the OA progression was monitored histologically at five weeks post-injury. The MV treatment reduced the OA-induced losses of articular cartilage area and thickness, decreased irregularity in the articular cartilage surface, reduced loss of gliding/intermediate zone of articular cartilage, reduced osteophyte formation, suppressed synovial inflammation, and decreased the OARSI OA score. In summary, treatment with osteoclastic MVs delayed or reversed OA progression. Thus, this study supports the feasibility of an osteoclastic MV-based therapy for OA. [ABSTRACT FROM AUTHOR]

This study aims to investigate the flexural performance of ultra-high-performance concrete (UHPC) wet joints subjected to vibration load during the early curing period. The parameters investigated included vibration amplitude (1 mm, 3 mm, and 5 mm) and vibration stage (pouring—final setting, pouring—initial setting, and initial setting—final setting). A novel simulated vibration test set-up was developed to reproduce the actual vibration conditions of the joints. The actuator's reaction force time-history curves for the UHPC joint indicate that the reaction force is stable during the initial setting stage, and it increases linearly with time from the initial setting to the final setting, trending toward stability after 16 h of casting. Under the vibration of 3 Hz-5 mm, cracks measuring 14 cm × 0.2 mm emerge in the UHPC joint. It occurs during the stage from the initial setting to the final setting. The flexural performance of wet joint specimens after vibration was evaluated by the four-point flexural test, focusing on failure modes, load-deflection curves, and the interface opening. The results show that all specimens with joints exhibited bending failure, with cracks predominantly concentrated at the interfaces and the sides of the NC precast segment. The interfacial bond strength was reduced by vibrations of higher amplitude and frequency. Compared with the specimens without vibration, the flexural strength of specimens subjected to the vibration at 3 Hz-3 mm and 3 Hz-5 mm were decreased by 8% and 19%, respectively. However, as the amplitude and frequency decreased, the flexural strength of the specimens showed an increasing trend, as this type of vibration enhanced the compactness of the concrete. Additionally, the calculation model for the flexural strength of UHPC joints has been established, taking into account the impact of live-load vibration. The average ratio of theoretical calculation values to experimental values is 1.01, and the standard deviation is 0.04, the theoretical calculation value is relatively precise. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD)-associated spondyloarthritis (SpA) is common but remains poorly understood. In this review article, we aimed to provide guidance regarding the diagnosis and management of this condition. For diagnosis of IBD-associated peripheral SpA (IBD-pSpA), we recommend collaboration with rheumatology for incorporation of clinical symptoms, physical examination findings, joint imaging if applicable, and available diagnostic criteria. For the management of IBD-pSpA, we first recommend assessment and treatment of underlying luminal IBD disease activity. We provide guidance regarding positioning of advanced therapies for IBD in patients with IBD-pSpA based on the limited available literature. For diagnosis of IBD-associated axial SpA, we recommend rheumatology referral to make the diagnosis based on incorporation of symptoms, laboratory data, imaging findings (sacroiliitis), and available diagnostic criteria. For the management of axial SpA, we recommend comanagement with rheumatology and use of either antitumor necrosis factor agents or Janus kinase inhibitors, when applicable. [ABSTRACT FROM AUTHOR]

Acromegaly is a chronic endocrine disease characterized by excessive secretion of growth hormone, which, in turn, leads to an increase in the secretion of insulin-like growth factor 1 in the liver. The targets for these hormones are most of the cells in our body. Excess growth hormone (in the vast majority of cases caused by hormone-producing pituitary adenoma – somatotropinoma), insulin-like growth factor leads to cellular, and tissue growth of almost all organs and systems, including the osteoarticular apparatus. Diagnosis of the disease in the early stages is often difficult and is established 5–10 years after the onset of symptoms, that leads to various complications and disability of patients. Often joint pain is the first manifestation of acromegaly. Damage to the musculoskeletal system causes a significant deterioration in the quality of life even when long-term stable remission of the underlying disease is achieved. In the article a clinical case with the peculiarities of diagnosing rheumatic disease in acromegaly is presented. A patient aged 56 years was diagnosed with acromegaly based on clinical and laboratory data, and a month later she underwent transnasal adenomectomy. However, Endocrinology Research Centre drew attention to the patient's complaints of pain in large joints, and therefore she was referred for a consultation to a rheumatologist at the Nasonova Research Institute of Rheumatology. As part of the examination, an increase in the titer of the antinuclear factor (1/2560) and the level of antibodies to ribonucleoprotein was revealed, which is most typical for mixed connective tissue disease. Treatment was prescribed and dynamic monitoring is being carried out.

Abstract Background Thermography is an emerging imaging modality which allows for a quick and objective measure of joint surface temperature in patients with rheumatoid arthritis (RA). To date, there are no published studies comparing thermography with ultrasonography in the subclinical assessment of joint inflammation at the wrist of patients with RA, and no published data on inter-rater reliability for multiple raters for thermographic assessment at the RA wrist. In our study comparing thermography and ultrasonography at the RA wrist, we aim to determine if thermography can detect subclinical synovitis. Additionally, we performed inter-reliability testing (multiple raters) for both thermography and ultrasonography. Methods Thermographic (average (Tavg), maximum (Tmax) and minimum (Tmin) temperatures) and ultrasound (total grey-scale (TGS) score and total power Doppler (TPD) scores) parameters were compared between two patient groups: Asymptomatic Group (with non-swollen and non-tender wrists) and Symptomatic Group (with swollen and/or tender wrists). Among Asymptomatic Group patients, thermographic parameters were compared between those with and without wrist joint recess(es) having ultrasound synovitis (PD ≥ 1 or GS ≥ 2); Spearman’s correlation and simple linear regression were used to study the relationship between thermographic and ultrasound parameters. Intra-class correlation coefficient (ICC) was used for inter-rater reliability calculation. Results Eighty-seven RA patients’ right wrists were imaged in this cross-sectional study. Thermographic temperatures, TPD and TGS scores were all significantly (p

Abstract In current timber structures, the low initial stiffness, and weak bending resistance of the connections result in significant structural deformation and failures. To improve the mechanical capabilities of timber structural joints, a novel timber-component anchorage system with robust bending resistance was introduced. Thirteen scaled-down specimens of glulam columns with anchored connections were meticulously fabricated for testing, scaled at a ratio of 1/2. Cyclic loading tests were conducted, considering three types of the volume compression percentage of confined wood perpendicular to the grain; and five axial-load levels. Subsequently, various seismic performance aspects of glulam columns with anchored connections were examined, including the failure mode, hysteresis behavior, envelope curve, strength degradation, stiffness degradation, energy dissipation capacity, and critical points. During the analysis, the influence of the P–Δ effect on the results was discussed and a damage-based hysteretic model was presented. Finally, a comparison of the mechanical performance for various types of timber structural joints was conducted. The findings revealed that the failure mode of the anchored glulam columns occurred as cracking perpendicular to the grain, and the anchored columns exhibited superior bending resistance and overall seismic performance.

Over the past few decades, composite joints have been regarded as one of the most promising approaches. After reviewing the research articles dealing with composite beam-column joints, it can be withdrawn that few researchers studied and developed different types of composite beam-column joints. The objectives of this paper to study the effect and behavior of different connection types on the composite beam – column joint under repeated loading as well as to investigate new forms of slab connection with column flange in composite connection joints, aiming to enhance the behaviors of the joints and make the slab endure a part of the load in a more efficient way. Five specimens with various connection types were tested to failure; the composite model number two (CM2) was considered the control specimen. Regarding the ultimate moment, the result found that CM5 has moment 50.47% more than control specimen, the lowest rotation value was in CM5. The general behaviours of the FEM were in good accordance with the experiment results. According to the parametric a higher yield strength is more rigid stiffer, the effect of web thickness on the load is too small and increase in load resistance with an increase in beam flange thickness.

Rigid aircraft pavements are generally comprised of unreinforced concrete slabs constructed on a bound or granular sub-base layer, over the natural or constructed subgrade or fill. Important to any rigid aircraft pavement design and construction are the joints between the concrete slabs. The joints control shrinkage cracks during curing, allow for thermal expansion and contraction during temperature cycles, they isolate concrete slabs from structural penetrations and importantly, provide load transfer between adjacent slabs. Load transfer is commonly modelled using finite element methods; however, any new model should be validated against observed physical events. Recently, full-scale testing was performed at the Federal Aviation Authority National Airport Pavement Testing Facility as part of Construction Cycle 8 (CC8), which investigated load transfer characteristics for a range of joint types. The results from CC8 tests provide up-to-date stress and strain values to validate any new finite element model. This paper presents the development of a finite element model to predict load transfer of a doweled construction joint, and its validation against CC8 test results. The model showed good agreement with CC8 test results, and now that it is validated, will be used to investigate innovative joint solutions for rigid aircraft pavements. [ABSTRACT FROM AUTHOR]

There is an unambiguous sex disparity in the field of orthopaedic surgery, with women making up only 7.4% of practicing orthopaedic surgeons in 2022. This study seeks to evaluate the sex distribution among orthopaedic surgeons engaged in primary total knee arthroplasty (TKA) between 2013 and 2020, as well as the procedural volume attributed to each provider. We retrospectively queried the Medicare dataset to quantify all physicians reporting orthopaedic surgery as their specialty and performing primary TKA from 2013 to 2020. Healthcare Common Procedure Coding System codes for primary TKA procedures were used to extract associated utilization and billing provider information. Trend analyses were performed with 2-sided correlated Mann-Kendall tests to evaluate trends in the number of surgeons by sex and the women-to-men surgeon ratio. During the study period, 6,198 to 7,189 surgeons billed for primary TKA. Of this number, an average of 2% were women. The mean number of procedures billed for by men was 39.02/y (standard deviation: 34.54), and by women was 28.76/y (standard deviation: 20.62) (P <.001). There was no significant trend in the number of men or women surgeons who billed for primary TKA during the study period. Trend analysis of the women-to-men ratio demonstrated an increasing trend of statistical significance (P =.0187). There was a significant upward trend in the women-to-men ratio of surgeons who billed for primary TKA. However, there remains a colossal gender gap, as women only made up 2.4% of surgeons who billed for the procedure. The current study raises awareness of the notable discrepancy in the average number of TKAs performed by women as compared to men. The orthopaedic community should aim to determine ways to increase the number of women arthroplasty surgeons along with the opportunities that women have to perform TKAs. [ABSTRACT FROM AUTHOR]

This paper presents an analytical investigation of glass fiber–reinforced polymer (GFRP) reinforced concrete knee joints subjected to closing moments, with a focus on reinforcement ratio, joint geometry, and confinement stirrups. The study uses the finite-element method with a commercially available code to verify experimental tests and examines the behavior of the knee joints through a parametric study. The concrete damaged plasticity model was used to define the material behavior of concrete, and the effects of different dilation angles were also studied. The average test-to-predicted ratios between finite-element analyses and test results fall within a range of 2% for moment capacities and 5% for deflections at peak. The results indicate that the dilation angle significantly influences the moment capacity and the ultimate deflection of specimens. Proper reinforcement detailing and concrete confinement are found to be important in knee joints, as unconfined specimens failed at significantly lower strengths than their confined counterparts. Incorporating diagonal stirrups in the knee joints is shown to be more effective than utilizing lateral stirrups in enhancing both moment capacity and deflections of the specimens under closing moments. However, placement of lateral stirrups is more practical than diagonal stirrups and it is shown that lateral stirrups increase the capacity of the joints to acceptable levels. [ABSTRACT FROM AUTHOR]

Introduction: The haemophilia joint health score (HJHS) is a tool used to assess joint changes in patients with haemophilia. There is lack of consensus on the interpretation of HJHS scores and their clinical relevance. Aim: To evaluate available literature reporting HJHS changes over time and assess a possible cut‐off value for clinically relevant outcomes and the ideal follow‐up for a meaningful score change. Methods: We conducted a literature search of studies published between 2011 and 2023 where the HJHS version 2.1 had been adopted to detect changes in joint health in patients with haemophilia. We focused on studies that assessed clinical relevance of HJHS changes, evaluated the use of cut‐off values and reported a follow‐up over time. Results: Our search identified 213 publications of which 53 (25%) were deemed relevant for this review. Of these, 33 (62%) publications reported the total HJHS score and 20 (38%) reported a single joint HJHS score, while the way of reporting HJHS scores/change was highly variable. Ten publications (19%) assessed clinical relevance, but their methods of calculation differed (defining a cut‐off score, measuring standardised response mean or minimal detectable change). The follow‐up duration varied from 2 weeks to 8 years in these 10 studies. Conclusions: High variability in assessing HJHS change over time is the primary consequence of its low sensitivity, and the lack of consensus on interpretation and clinical relevance of the score. Therefore, more sensitive tools should be used alongside HJHS to better define the joint health status of patients with haemophilia. [ABSTRACT FROM AUTHOR]

The capacity and stiffness of laminated bamboo lumber (LBL) shear wall sheathed by oriented strand boards (OSBs) is significantly influenced by the structural performance of the nailed connections. Single-connector sheathing-to-framing connections were experimentally tested under monotonic and cyclic loading. The parameters investigated were the nail diameter, the loading direction, the edge distances of nails in the OSB and the LBL. The minimum edge distance for nails in both the LBL stud and the OSB panel was found to be 15 mm. Nails with a smaller edge distance within the members are at higher risk of failing prematurely under lower loads, demonstrating a brittle failure mode. The specimens subjected to cyclic and monotonic loading showed quite different damage. Fatigue fracture due to repeated reverse bending was the typical failure mode for nails in the cyclic experiments. The maximum load of the specimens increased with a larger nail diameter and the load-carrying capacity of parallel-to-grain specimens was greater than that of perpendicular-to-grain specimens. The energy-dissipation capacity of the connections increased with an increase in nail diameter and an increase in the edge distance of the nail in both the LBL and the OSB. [ABSTRACT FROM AUTHOR]

Composite sandwich structures, which are widely employed in engineering structures, require a multitude of inserts. In certain instances, the necessity for a specialized insert arises from the unique characteristics of a particular application. In applications such as weather radar radomes, double-curved sandwich panels should be designed with electromagnetic (EM) transparency as a primary objective. The use of metal inserts should be restricted to the absolute minimum. Given the limitations of using metal materials to protect against EM radiation and the need to enhance the load-bearing capacity of the joint against pull-out loads, a composite insert has developed as an innovative solution. In this study, a composite insert of a double-curved sandwich dome has been developed using silica nanoparticles, and its mechanical strength against pull-out load has been evaluated through both experimental and numerical analysis. The strength results obtained have been compared with analytical estimates. Additionally, the buckling of the double-curved sandwich dome against a wind speed of 220 km/h has been investigated numerically. The critical buckling load for wind loading for the full-scale sandwich radome was estimated to be 16,303 N. According to the numerical results obtained with the Abaqus finite element (FE) software, the maximum pull-out force applied to the connection area is approximately 10.7 kN. A parametric study of geometric variables and experimental results showed that it is possible to achieve a stronger composite insert (by 1 wt % nano silica particles) by 20.7% lighter and 102.65% more bearing capacity. [ABSTRACT FROM AUTHOR]

Background/Objectives: Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthritis. We aim to study subclinical PD synovitis and thermographic joint inflammation assessment in patients with RA. Methods: We compared (1) PD synovitis at clinically quiescent (non-swollen; non-tender) joints based on patients' disease activity and (2) thermography (hands/wrists) outcomes based on PD joint inflammation findings and patient's disease activity. Results: Among eighty RA patients (mean (SD) age 57.0 (12.6) years; 61 of whom (76.3%) were female), the wrists (62.7%), second metacarpophalangeal joints (MCPJs) (37.0%), third MCPJs (33.8%), fourth MCPJs (24.8%), and fifth MCPJs (20.9%) were the five joint sites most frequently displaying subclinical PD synovitis; with no statistically significance differences (p > 0.05) between patients with 28-joint disease activity score (DAS28) < 3.2 versus those with DAS28 ≥ 3.2. At these five joint sites bilaterally, (1) the total maximum (Total Tmax), total average (Total Tavg), and total minimum (Total Tmin) temperatures were significantly greater (p < 0.05) for Total PD (TPD) score >1 versus TPD score ≤ 1, while their area under the ROC curve (AUC) values in identifying TPD score >1 ranged from 0.789 to 0.810, and (2) Total Tmax, Total Tavg, Total Tmin, and TPD score were significantly greater (p < 0.05) for patients with DAS28 ≥ 3.2 versus those with DAS28 < 3.2. Conclusions: Our results would serve as useful background data in studies on RA monitoring strategies detecting subclinical PD synovitis. Thermographic temperatures were greater in patients with greater disease activity and can help discriminate ultrasound PD joint inflammation severity. [ABSTRACT FROM AUTHOR]

Vehicle loads and differential ground movements can induce tensile strains in close-fitting polymer liners installed within gravity flow pipes, where the liner stretches across ring fractures or joints experiencing rotation (i.e., opening of the joint at the invert if the joint is moving down relative to the other ends of the pipe segments, or at the crown if the joint is moving upward compared with the other ends). A finite-element model is established and suitable pipe length and mesh size are determined. The stress and strain distributions along hoop and axial directions are then evaluated, considering factors such as inside diameter of the host pipe, liner thickness, rotation angle, liner elastic modulus, friction coefficient between the liner and host pipe, and Poisson's ratio of the liner. After that, curve fitting is used to develop design equations for estimating stress and strain, and their performance is evaluated against the finite-element data. Finally, the potential effects of gravity and buoyancy are investigated. For small rotations, the stress is proportional to strain, and the maximum stress of the liner occurs directly at the joint, at the point where joint opening is greatest. The friction coefficient and liner thickness have a small effect on the maximum stress, so this simplifies consideration of this limit state in design. The design equation for stress provides estimates within 8.6% of those obtained from the three-dimensional finite-element analysis (with R2 between 0.992 and 0.993). Subsequent evaluation of the proposed equation using strain measurements obtained from full-scale experiments is recommended. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is highly transmissible and affects the respiratory system. People with COVID-19 are at higher risk of physical and mental health conditions, which could impact bone health. The aim of this review was to explore the effects of COVID-19 on BMD, BTMs, and joints. An electronic search of the PubMed, Web of Science, Scopus, and Ovid Medline databases considered studies published between 1 January 2020 and 1 November 2023. The search was limited to English, original studies in adult humans. The title and abstract of the identified papers were screened, followed by a full-text review using inclusion and exclusion criteria. The data extracted included the study and participant characteristics, BTMs, BMD, and joint abnormalities. The Newcastle–Ottawa scale quality assessment tool was used to assess the risk of bias. Five studies involving 305 out of 495 infected individuals observed a reduced BMD after COVID-19, with the most significant reduction occurring a year later. Both bone resorption and bone formation markers decreased, while regulatory markers showed higher levels in infected patients. COVID-19 may harm bone health by increasing bone regulatory markers and reducing bone formation and absorption, leading to a lower BMD. Elderly, frail, and osteopenic or osteoporotic individuals are at higher risk and should be regularly monitored for bone loss if they have long COVID. [ABSTRACT FROM AUTHOR]

In the present study, a simple and reliabe small-scale laboratory test to assess the performance of aggregate interlocked joints in short-panelled concrete pavements in terms of LTE is proposed. In the proposed test method, conventional standard flexural strength test beam specimens (100×100× 500mm) are used for understanding the performance of aggregate interlocking of PQC mix specimens prepared using coarse aggregates of different NMAS and with addition of both micro and macro fibers. The test setup is also modelled in ANSYS FE software. The experimentally obtained LTE is compared with the LTE obtained from the FE model. The field FWD test is conducted for validation. The relative movement is determined from FWD test, and corresponding LTE is determined using the LTE and RM relationship obtained from experimental results using the proposed test apparatus. There exists good linear fit between the LTE determined using proposed test and field FWD test results. [ABSTRACT FROM AUTHOR]

In current timber structures, the low initial stiffness, and weak bending resistance of the connections result in significant structural deformation and failures. To improve the mechanical capabilities of timber structural joints, a novel timber-component anchorage system with robust bending resistance was introduced. Thirteen scaled-down specimens of glulam columns with anchored connections were meticulously fabricated for testing, scaled at a ratio of 1/2. Cyclic loading tests were conducted, considering three types of the volume compression percentage of confined wood perpendicular to the grain; and five axial-load levels. Subsequently, various seismic performance aspects of glulam columns with anchored connections were examined, including the failure mode, hysteresis behavior, envelope curve, strength degradation, stiffness degradation, energy dissipation capacity, and critical points. During the analysis, the influence of the P–Δ effect on the results was discussed and a damage-based hysteretic model was presented. Finally, a comparison of the mechanical performance for various types of timber structural joints was conducted. The findings revealed that the failure mode of the anchored glulam columns occurred as cracking perpendicular to the grain, and the anchored columns exhibited superior bending resistance and overall seismic performance. [ABSTRACT FROM AUTHOR]

Beam-column (B-C) joints are recognized as critical regions in reinforced concrete (RC) moment-resisting frames when subjected to seismic loads. Furthermore, these joints may be subjected to high temperatures during their lifespan, which might cause severe structural damage. Accordingly, the seismic response of RC beam-column joints that were subjected to heat (i.e., 400 °C and 600 °C) was investigated in the present experimental work. The joint specimens were divided into three categories: Three joints were kept as is (i.e., reference joints; no strengthening is applied), whereas six joints were strengthened with one and two layers of stainless-steel expanded metal sheet mesh (SSEMSM) in order to improve their performance. To investigate the seismic performance of the joints, a quasi-static cyclic load was applied to the joints to simulate a seismic load. Results showed that the average maximum load for joints strengthened with one and two layers of SSEMSM, respectively, was increased by 11% and 21% at ambient temperature and by 2% and 9% at 400 °C, in comparison with the reference joint. In addition, using one and two layers of SSEMSM, respectively, led to achieving an average of 91% and 100% of the full capacity of the reference joint for B-C joints subjected to 600 °C. Furthermore, the experimental findings show a considerable improvement in the cyclic response of non-ductile RC joints that were strengthened with the SSEMSM strategy and subjected to high temperatures (i.e., higher load capacity, greater displacement, higher dissipated energy, higher ductility, and slower degradation in the secant stiffness). [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) flat-slab structures may experience progressive collapse, usually caused by the punching shear failure of slab–column joints. Existing research has shown that the use of shear reinforcements or ultra-high toughness cementitious composites (UHTCCs) in slab–column joints is efficient in improving their punching shear performance. In this study, shear reinforcement was introduced into UHTCC-enhanced RC slab–column joints. Specimens of UHTCC-enhanced slab–column joints were tested considering the effect of shear reinforcements. The cracking development process, bearing capacity and ductility were analysed. Yield line theory and critical shear crack theory were adopted to predict flexural and punching shear capacities, respectively. Finally, the failure patterns of the specimens were distinguished by comparing the predicted punching shear and flexural capacities, taking ductility coefficients into account. The theoretical and test results show the effect of shear reinforcement on the behaviour of UHTCC-enhanced joints. Significant improvements in the bearing capacity and ductility of the joints was achieved by applying shear reinforcement. The failure pattern of the joint varied from premature punching shear failure to flexural-triggered punching shear failure with the application of UHTCC, and this transformation was more pronounced with shear reinforcement applied into the UHTCC-enhanced joint. [ABSTRACT FROM AUTHOR]

The performance of concrete-filled steel tubular (CFST) column joints with a group of extended hollo-bolts has been experimentally investigated under the influence of shear loading. The primary focus was to understand the performance of extended hollo-bolts in enhancing the transfer of shear load to the concrete core of the column by bolt bearing. The joint assembly was fabricated with a rigid end-plate, thereby overcoming the influence of endplates in the joint global behavior. A series of full-scale group hollo-bolted CFST column joint tests was carried out, where eight specimens were fabricated with a group of two hollo-bolts, arranged in one row and two rows in the assembly; another five specimens were fabricated with a group of four hollo-bolts, arranged in two rows. Apart from bolt arrangement, the other parameters studied included the use of standard and extended hollo-bolts, the embedment length of the hollo-bolt, and the bolt pitch distance. From the investigation, it is observed that all the joints failed in pure shear signifying utilization of the full capacity of the hollo-bolt, and no prominent bearing failure of concrete was observed. Enhanced composite behavior was achieved using the extended hollo-bolts as the shear load was transferred to the concrete core effectively. A group of two extended hollo-bolts in a single row transmits equal forces to the concrete core, whereas, when two or four extended hollo-bolts are in two rows, the upper row transmits more forces as compared to the bolts in the lower row. Lastly, with pitch distance of 2.5 times bolt hole diameter and beyond, the total strength of the joint is equal to the sum of strength of individual bolts, which confirms that the group action did not deteriorate the joint capacity. Subsequently, an analytical model for the global force-displacement behavior and joint shear strength is proposed by calibrating the test data obtained through this study. [ABSTRACT FROM AUTHOR]

The wear resistance and surface hardness of crankshaft journals in diesel engines sent for repair are studied. The wear is greater for the main journals than for the journals of the connecting rods. The surface hardness is lower for worn shafts. [ABSTRACT FROM AUTHOR]

Purpose Mastering the skill of smashing in a game can be quite challenging. Unfortunately, it’s not always easy to control the distance of the smash. The present study investigated the impact of different smashing distances on muscle activation patterns and kinematics of the upper limbs. Material and methods Ten collegiate athletes from a top-ranked team in Korea participated in the present study with a mean age, weight, and height of 21 ± 1 years, 71.9 ± 9.1 kg, and 1.78 ± 2.24 m, respectively. Three valid data points for each subject at three different distances were analyzed using a one-way analysis of variance (ANOVA). Results The results demonstrated that with increasing smashing distance, the internal rotation angle of the elbow and wrist joints decreased, while the angular velocity of flexion and internal rotation of the shoulder, elbow, and wrist joints increased. Muscle activation increased for all muscles except the biceps brachii (BICLO) with increasing distance. The greatest changes in activation levels were observed in the anterior deltoid (DELTA), extensor carpi radialis (ECR), and flexor carpi ulnaris (FCU). Conclusions During tasks with different smashing distances, muscle activation in the upper limbs (except the biceps) increased with increasing distances. Additionally, the internal rotation angle of the upper limbs decreased with increased distances, while the angular velocity of flexion and internal rotation of the shoulder, elbow, and wrist joints increased.

Acromegaly is a rare neuroendocrine disease caused by excessive production of growth hormone (GH), which acts as a trigger for cartilage tissue destruction leading to joint damage.Patients with acromegaly, especially in the active stage, often complain of joint pain in various locations. Joint pain can be one of the first symptoms of the disease, the intensity of which worsens without proper treatment. Increased production of GH leads to configuration changes in the joints, which in turn trigger destructive processes typical of degenerative diseases such as osteoarthritis. Despite successful treatment of acromegaly, joint-related issues can persist and significantly worsen the quality of life for patients. In this regard, the search for potential markers of early joint involvement in acromegaly is relevant for use in predicting the severity of arthropathy progression and monitoring this cohort of patients.This review provides a general overview of the effects of growth hormone on cartilage tissue, the characteristics of musculoskeletal pathology in patients with acromegaly and possible markers associated with early joint damage.

Abstract Background Generalized Joint Hyper-mobility (GJH) can aid in the diagnosis of Ehlers-Danlos Syndrome (EDS), a complex genetic connective tissue disorder with clinical features that can mimic other disease processes. Our study focuses on developing a unique image-based goniometry system, the HybridPoseNet, which utilizes a hybrid deep learning model. Objective The proposed model is designed to provide the most accurate joint angle measurements in EDS appraisals. Using a hybrid of CNNs and HyperLSTMs in the pose estimation module of HybridPoseNet offers superior generalization and time consistency properties, setting it apart from existing complex libraries. Methodology HybridPoseNet integrates the spatial pattern recognition prowess of MobileNet-V2 with the sequential data processing capability of HyperLSTM units. The system captures the dynamic nature of joint motion by creating a model that learns from individual frames and the sequence of movements. The CNN module of HybridPoseNet was trained on a large and diverse data set before the fine-tuning of video data involving 50 individuals visiting the EDS clinic, focusing on joints that can hyperextend. HyperLSTMs have been incorporated in video frames to avoid any time breakage in joint angle estimation in consecutive frames. The model performance was evaluated using Spearman’s coefficient correlation versus manual goniometry measurements, as well as by the human labeling of joint position, the second validation step. Outcome Preliminary findings demonstrate HybridPoseNet achieving a remarkable correlation with manual Goniometric measurements: thumb (rho = 0.847), elbows (rho = 0.822), knees (rho = 0.839), and fifth fingers (rho = 0.896), indicating that the newest model is considerably better. The model manifested a consistent performance in all joint assessments, hence not requiring selecting a variety of pose-measuring libraries for every joint. The presentation of HybridPoseNet contributes to achieving a combined and normalized approach to reviewing the mobility of joints, which has an overall enhancement of approximately 20% in accuracy compared to the regular pose estimation libraries. This innovation is very valuable to the field of medical diagnostics of connective tissue diseases and a vast improvement to its understanding.

Abstract Background Step width is a spatial variable in the frontal plane, defined as the mediolateral distance between the heel (forefoot during sprinting) of bilateral feet at initial contact. Variations in step width may impact the lower limb biomechanics. This systematic review aimed to synthesize the published findings to determine the influence of acute changes in step width on locomotion biomechanics and provide implications for injury prevention and enhanced sports performance. Methods Literature was identified, selected, and appraised in accordance with the methods of a systematic review. Four electronic databases (Web of Science, MEDLINE via PubMed, Scopus, and ScienceDirect) were searched up until May 2023 with the development of inclusion criteria based on the PICO model. Study quality was assessed using the Downs and Black checklist and the measured parameters were summarized. Results Twenty-three articles and 399 participants were included in the systematic review. The average quality score of the 23 studies included was 9.39 (out of 14). Step width changed the kinematics and kinetics in the sagittal, frontal, and transverse planes of the lower limb, such as peak rearfoot eversion angle and moment, peak hip adduction angle and moment, knee flexion moment, peak knee internal rotation angle, as well as knee external rotation moment. Alteration of step width has the potential to change the stability and posture during locomotion, and evidence exists for the immediate biomechanical effects of variations in step width to alter proximal kinematics and cues to impact loading variables. Conclusion Short-term changes in step width during walking, running, and sprinting influenced multiple lower extremity biomechanics. Narrower step width may result in poor balance and higher impact loading on the lower extremities during walking and running and may limit an athlete’s sprint performance. Increasing step width may be beneficial for injury rehabilitation, i.e., for patients with patellofemoral pain syndrome, iliotibial band syndrome or tibial bone stress injury. Wider steps increase the supporting base and typically enhance balance control, which in turn could reduce the risks of falling during daily activities. Altering the step width is thus proposed as a simple and non-invasive treatment method in clinical practice.