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Purpose: This study investigated the test–retest reliability and usefulness of the foot–ankle rebound-jump test (FARJT) for measuring foot–ankle reactive strength metrics in athletes. Methods: Thirty-six highly trained, healthy athletes (5 female; 21.5 [3.9] y; 1.80 [0.10] m; 72.7 [10.4] kg) performed 8 repeated bilateral vertical foot–ankle rebound jumps on 2 testing days. Testing days were 1 week apart, and these sessions were preceded by a familiarization session. Reactive strength metrics were calculated by dividing jump height (in meters) by contact time (in seconds) for the reactive strength index (RSI) and flight time (in seconds) by contact time (in seconds) for the reactive strength ratio (RSR). The mean of 4 jumps (excluding the first and last 2 jumps) on each testing session were considered for RSI and RSR reliability and usefulness analysis. Results: We found a high reliability of the FARJT for RSI (intraclass correlation coefficient [ICC] >.90 and coefficient of variation [CV] = 12%) and RSR (ICC ≥.90 and CV = 8%). Regarding their usefulness, both RSI and RSR were rated as "marginal" in detecting the smallest worthwhile change (typical error > smallest worthwhile change) and "good" in detecting a moderate change in performance. Conclusions: The results showed that a FARJT is a highly reliable test for measuring foot–ankle reactive strength in athletes and useful for quantifying changes, for example, following a training block. However, its usefulness as an accurate daily or weekly monitoring tool in practice is questionable. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) accounts for about 90% of all pancreatic cancer cases. Five-year survival rates have remained below 12% since the 1970s, in part due to the difficulty in detection prior to metastasis (migration and invasion into neighboring organs and glands). Mechanical memory is a concept that has emerged over the past decade that may provide a path toward understanding how invading PDAC cells "remember" the mechanical properties of their diseased ("stiff", elastic modulus, E ≈ 10 kPa) microenvironment even while invading a healthy ("soft", E ≈ 1 kPa) microenvironment. Here, we investigated the role of mechanical priming by culturing a dilute suspension of PDAC (FG) cells within a 3D, rheologically tunable microgel platform from hydrogels with tunable mechanical properties. We conducted a suite of acute (short-term) priming studies where we cultured PDAC cells in either a soft (E ≈ 1 kPa) or stiff (E ≈ 10 kPa) environment for 6 h, then removed and placed them into a new soft or stiff 3D environment for another 18 h. Following these steps, we conducted RNA-seq analyses to quantify gene expression. Initial priming in the 3D culture showed persistent gene expression for the duration of the study, regardless of the subsequent environments (stiff or soft). Stiff 3D culture was associated with the downregulation of tumor suppressors (LATS1, BCAR3, CDKN2C), as well as the upregulation of cancer-associated genes (RAC3). Immunofluorescence staining (BCAR3, RAC3) further supported the persistence of this cellular response, with BCAR3 upregulated in soft culture and RAC3 upregulated in stiff-primed culture. Stiff-primed genes were stratified against patient data found in The Cancer Genome Atlas (TCGA). Upregulated genes in stiff-primed 3D culture were associated with decreased survival in patient data, suggesting a link between patient survival and mechanical priming.

Purpose: Advanced footwear technology is prevalent in distance running, with research focusing on these "super shoes" in competitive athletes, with less understanding of their value for slower runners. The aim of this study was to compare physiological and biomechanical variables between a model of super shoes (Saucony Endorphin Speed 2) and regular running shoes (Saucony Cohesion 13) in recreational athletes. Methods: We measured peak oxygen uptake (VO2peak) in 10 runners before testing each subject 4 times in a randomly ordered crossover design (ie, Endorphin shoe or Cohesion shoe, running at 65% or 80% of velocity at VO2peak [vVO2peak]). We recorded video data using a high-speed camera (300 Hz) to calculate vertical and leg stiffnesses. Results: 65% vVO2peak was equivalent to a speed of 9.4 km·h−1 (0.4), whereas 80% vVO2peak was equivalent to 11.5 km·h−1 (0.5). Two-way mixed-design analysis of variance showed that oxygen consumption in the Endorphin shoe was 3.9% lower than in the Cohesion shoe at 65% vVO2peak, with an interaction between shoes and speed (P =.020) meaning an increased difference of 5.0% at 80% vVO2peak. There were small increases in vertical and leg stiffnesses in the Endorphin shoes (P <.001); the Endorphin shoe condition also showed trivial to moderate differences in step length, step rate, contact time, and flight time (P <.001). Conclusions: There was a physiological benefit to running in the super shoes even at the slower speed. There were also spatiotemporal and global stiffness improvements indicating that recreational runners benefit from wearing super shoes. [ABSTRACT FROM AUTHOR]

The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.

Objectives: Although nonsurgical and surgical management of knee arthrofibrosis has been reported in the literature, there is little information on the effect of procedural treatment modalities of refractory arthrofibrosis on clinical outcomes. The purpose of this case report is to describe the intervention of refractory knee arthrofibrosis after anterior cruciate ligament reconstruction and investigate long-term clinical outcomes after procedural intervention. Methods: A 27-year-old male presented with decreased range of motion (ROM), patellar mobility, strength, and knee joint function following anterior cruciate ligament reconstruction of his left knee. After failed conservative management, the patient underwent manipulation under anesthesia (MUA) to release scar tissue. Following MUA, the emphasis of comprehensive physiotherapy was on decreasing inflammation, relieving pain, and maintaining patellar mobility while increasing knee joint ROM and strength. Knee ROM, patellofemoral motion, gait, and quadriceps recruitment were measured 3, 6, 12, and 24 months after MUA. Results: At 2-year follow-up after MUA, the patient continued to present with decreased ROM and quadriceps strength compared to the contralateral knee, but had returned to a running program and reported knee joint dysfunction no longer interfered with his daily activities. Conclusions: This case report demonstrates signs and symptoms that could indicate knee arthrofibrosis and introduces procedural intervention for refractory arthrofibrosis after anterior cruciate ligament reconstruction. [ABSTRACT FROM AUTHOR]

Stiffness remains a common complication after primary total knee arthroplasty (TKA). Manipulation under anesthesia (MUA) is the gold standard treatment for early postoperative stiffness; however, there remains a paucity of data on the risk of MUA after primary TKA if a prior contralateral TKA required MUA. We performed a retrospective review of 3,102 patients who had staged primary TKAs between 2016 and 2021. The mean body mass index was 33 (range, 18 to 59) and the mean age was 67 years (range, 24 to 91). The mean preoperative range of motion for the first TKA was 2 to 104°, and for the contralateral TKA was 1 to 107°. The primary outcomes were MUA following first and second primary TKAs. Multivariable Poisson regressions were used to evaluate associations between risk factors and outcomes. The rate of MUA after the first TKA was 2.6% (n = 83 of 3,102) and 1.3% (n = 40 of 3,102) after the contralateral TKA. After adjustment, there was a nearly 14-fold higher rate of MUA after the second TKA if the patient had an MUA after the first TKA (relative risk, 13.80; 95% CI [confidence interval], 7.14 to 26.66). For the first TKA, increasing age (adjusted risk ratio [ARR], 0.65; 95% CI, 0.50 to 0.83) and increasing body mass index (ARR, 0.65; 95% CI, 0.47 to 0.90) were associated with lower risk for MUA. For the second TKA, increasing age was associated with a lower risk of MUA (ARR, 0.60; 95% CI, 0.45 to 0.80). For patients undergoing staged bilateral TKA, patients who undergo MUA following the first primary TKA are nearly 14-fold more likely to undergo an MUA following the contralateral primary TKA than those who did not have an MUA after their first TKA. [ABSTRACT FROM AUTHOR]

For a drive unit for axes of robots and robot-like systems (RLS) usually a motorgearbox arrangement is chosen due to its high-power density. The combination of a high-ratio gearbox and a high-speed electric motor ensures a very compact and efficient design of the drive train. The transmission properties primarily determine the properties of the axes and the whole robot system. Robots and RLS use various types of high-ratio precision gearboxes based on different operating principles. Due to the different operating principles, it is difficult to describe comparable properties across all different types. In addition, there are many influences on the properties which significantly determine their shapes and values. These influencing parameters are insufficiently documented and are often poorly accessible for profound comparability and further consideration. In this paper, an overview of the properties of robot gearboxes is given. Based on these properties, different robot gearboxes can be systematically evaluated and compared to one another. The properties are influenced by various design, operating or manufacturing factors such as the gearbox size, the operating torque and speed or the manufacturing process. In a further step, these influences on the most relevant properties, efficiency and stiffness, are determined and systematically evaluated. This evaluation is based on the specification data of various robot gearbox manufacturers. The properties efficiency and stiffness show a dependency on the gearbox size, the operating torque, speed as well as the ambient temperature and on the transmission ratio. The shown procedure can also be adapted to other properties. [ABSTRACT FROM AUTHOR]

The objective of this project was to further develop new composites and a testing program for the performance‐based specification for natural Amazonian geopolymer (GP) for use in ceramics and construction. While fly ash‐based alkali activated materials are now an established technology, metakaolin‐based GPs still need to be developed and optimized regarding the knowledge of the specific characteristics and properties of local resources. Amazonian kaolin was calcined into metakaolin (AMK). AMK particle size reduction for better reactive material was evaluated by means of dry and wet ball milling and sieving. Three types of metakaolin were analyzed for particle size distribution, and their size d50 ranged from 7.9 to 2.8 µm. Further GP characterization followed physical and mechanical properties in flexural strength tests. In addition, scanning electron microscopy and energy dispersive spectroscopy were used to investigate the microstructure of the materials. Energy dispersive X‐ray fluorescence was used to measure the GP material composition. Analysis of the results revealed that the strength and stiffness of sodium–metakaolin‐based GP were inversely proportional to particle size. All distinct particle size GPs showed, in general, some increase in strength and stiffness within curing times ranging from 3 to 28 days. [ABSTRACT FROM AUTHOR]

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty‐six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K‐wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16‐week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10‐week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose‐dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals. [ABSTRACT FROM AUTHOR]

In this article, a kind of original bamboo-fiber reinforced phosphogypsum composite wall was proposed. The axial compression tests of eight walls and finite element analysis were carried out. The failure modes and mechanical properties of the walls were explored, the influence of parameters on the axial compression performance of the walls was studied, and the calculation methods of the axial compression capacity and stiffness of the composite walls were proposed. The results show that the phosphogypsum cracked first in the composite walls during the loading process, the cracks gradually spreaded through and widened, and the bamboo tubes inside the composite walls were crushed. The buckling failure occurred in the pure original bamboo wall. The bearing capacity of the composite wall control specimen is 140% and 38.46% higher than that of the pure phosphogypsum wall and the pure original bamboo wall, respectively. The number of dovetail nails has no significant effect on the axial compression performance of the composite wall. The bearing capacity and stiffness of composite wall increase with the increase of bamboo number, wall thickness, bamboo wall thickness and phosphogypsum strength. The calculation method of axial bearing capacity and stiffness of composite wall based on bamboo content is proposed. The finite element simulation results are in good agreement with the experimental and theoretical calculation results. The theoretical calculation method has high accuracy. The composite wall realizes the complementary advantages of original bamboo and phosphogypsum, which provides reference for the development and application of green buildings. [ABSTRACT FROM AUTHOR]

The heat of mixing of some petrological relevant substitutions (i.e., Mg-Al, Si-Al, Mg-Ti, Mg-Ca, and Mg-Fe) was investigated systematically in silicates, titanates, tungstates, carbonates, oxides, hydroxides, and sulphates by density functional theory calculations (e.g., melilite, chlorite, biotite, brucite, cordierite, amphibole, talc, pseudobrookite, pyroxene, olivine, wadsleyite, ilmenite, MgWO4, ringwoodite (spinel), perovskite, pyrope-grossular, magnesite-calcite, MgO-CaO, anhydrous and different hydrated MgSO4). A specific substitution is characterised by different microscopic interaction energies in different minerals, e.g., the octahedral Mg-Al exchange on a single crystallographic site in pyroxene has a microscopic interaction energy that is more than twice compared to that in biotite. A comparative investigation of the heat of mixing using microscopic interaction energies on a single crystallographic site has the advantage that they are not influenced by cation ordering. They could be successfully correlated with the stiffnesses of the minerals, which in turn were scaled to the oxygen packing fraction, a parameter that is easily available for poorly investigated minerals. With this information, the interaction energies of a certain substitution can be transferred from minerals where they are well-known to mineral groups where they are less- or unknown. Using the cross-site terms and the microscopic interaction energies, the macroscopic interaction energies of the coupled substitution, e.g., Mg + Si = Al + Al, of biotite and pyroxene were calculated, which are, however, affected by cation ordering and different degrees of local charge balance, for which appropriate models are necessary. [ABSTRACT FROM AUTHOR]

The extracellular matrix (ECM) of cancer tissues is rich in dense collagen, contributing to the stiffening of these tissues. Increased stiffness has been reported to promote cancer cell proliferation, invasion, metastasis, and prevent drug delivery. Replicating the structure and mechanical properties of cancer tissue in vitro is essential for developing cancer treatment drugs that target these properties. In this study, we recreated specific characteristics of cancer tissue, such as collagen density and high elastic modulus, using a colorectal cancer cell line as a model. Using our original material, collagen microfibers (CMFs), and a constructed three-dimensional (3D) cancer-stromal tissue model, we successfully reproduced an ECM highly similar to in vivo conditions. Furthermore, our research demonstrated that cancer stem cell markers expressed in the 3D cancer-stromal tissue model more closely mimic in vivo conditions than traditional two-dimensional cell cultures. We also found that CMFs might affect an impact on how cancer cells express these markers. Our 3D CMF-based model holds promise for enhancing our understanding of colorectal cancer and advancing therapeutic approaches. Reproducing the collagen content and stiffness of cancer tissue is crucial in comprehending the properties of cancer and advancing anticancer drug development. Nonetheless, the use of collagen as a scaffold material has posed challenges due to its poor solubility, hindering the replication of a cancer microenvironment. In this study, we have successfully recreated cancer tissue-specific characteristics such as collagen density, stiffness, and the expression of cancer stem cell markers in three-dimensional (3D) colorectal cancer stromal tissue, utilizing a proprietary material known as collagen microfiber (CMF). CMF proves to be an ideal scaffold material for replicating cancer stromal tissue, and these 3D tissues constructed with CMFs hold promise in contributing to our understanding of cancer and the development of therapeutic drugs. [Display omitted] [ABSTRACT FROM AUTHOR]

Bernoulli pads are traditionally used for noncontact pick-and-place operations in industry. The normal force produced by a Bernoulli pad allows it to adhere to an object or workpiece. In addition to the normal force, the pad produces shear forces, which allows it to clean a workpiece without contact. A direct relationship between the inlet fluid power and the shear losses motivates us to explore other methods of providing power to the system with the objective of increasing shear forces and thereby improving cleaning efficacy. Here, we numerically investigate a system in which additional mechanical power is added by rotating the Bernoulli pad. The rotating system provides additional fluid forces (normal and shear) for the same inlet fluid power. For a specific pad that we investigated, the maximum wall shear stress increased by ≈15% and the normal force changed from +1.4 N (repulsive) to -6.6 N (attractive) for change in the rotational speed by 60 rad/s. Also, for a given normal attractive force, a stable equilibrium configuration can exist for two mass flow rates, with the higher mass flowrate resulting in a higher stiffness of the flow field. [ABSTRACT FROM AUTHOR]

Arthrofibrosis is a debilitating postoperative complication and a major cause of patient dissatisfaction following total knee arthroplasty (TKA). There is no consensus regarding the optimal treatment for stiffness after TKA. For cases not amenable to manipulation under anesthesia (MUA), one component or full revision are both suitable options. In a value-based healthcare era, maximizing cost-effectiveness with optimized clinical outcomes for patients remains the ultimate goal. As such, we compared (1) Knee Injury and Osteoarthritis Outcome Scores for Joint Replacement (KOOS, JR), (2) range of motion (ROM), as well as (3) complication rates, including MUA and lysis of adhesions (LOA), between polyethylene exchange and full component revision for TKA arthrofibrosis. Patients were queried from an institutional database who underwent revision TKA for arthrofibrosis between January 1, 2015, and April 31, 2021. There were 33 patients who underwent full revision and 16 patients who underwent polyethylene exchange. Demographics and baseline characteristics between the cohorts were analyzed. Postoperative outcomes included MUA, LOA, and re-revision rates as well as KOOS, JR, and extension and flexion ROM at a mean follow-up of 3.8 years. Baseline comorbidities, including age, body mass index, alcohol use, tobacco use, and diabetes, were comparable between the full revision and polyethylene exchange revision cohorts (P >.05). The one and full component revisions had similar preoperative KOOS, JR (43 versus 42, P =.85), and flexion (81 versus 82 degrees, P =.80) versus extension (11 versus 11 degrees, P =.87) ROM. The full component revision had higher KOOS, JR (65 versus 55, P =.04), and flexion (102 versus 92 degrees, P =.02), but similar extension (3 versus 3 degrees, P =.80) ROM at final follow-up compared to the polyethylene exchange revision, respectively. The MUA (18.2 versus 18.8%, P =.96) and LOA (2.0 versus 0.0%, P =.32) rates were similar between full component and polyethylene exchange revisions. There was one re-revision (3.0%) for the cohort of patients who initially underwent full revision. There were four full re-revisions (25.0%) and two polyethylene exchange re-revisions (12.5%) performed in the cohort of patients who initially underwent a polyethylene exchange revision. The full component revision for stiffness after TKA showed favorable KOOS, JR, ROM, and outcomes in comparison to the polyethylene exchange revision. While the optimal treatment for stiffness after TKA is without consensus, this study supports the use of the full component revision when applied to the institutional population at hand. It is imperative that homogeneity exists in preoperative definitions, preoperative baseline patient demographics, ROM and function levels, outcome measures, and preoperative indications, as well as the inclusion of clinical data that assesses complete exchange, single exchange, and tibial insert exchange. [ABSTRACT FROM AUTHOR]

The dynamics of thin-walled parts are highly affected by the clamping conditions. Clamping stiffness is a function of c lamping force and surface roughness profiles of the clamp and part. Since the surface profiles cannot be altered, estimating clamping stiffness as a function of the clamping force is essential to simulate vibrations of the machined thin-walled parts. This paper presents the modeling of clamping stiffness as a function of the applied clamping force and material properties. Surface profile parameters are estimated from the identified contact stiffnesses evaluated using the Finite Element (FE) model. The contact stiffnesses are either predicted directly from the proposed mechanics model of the part or estimated from the Fractal surface parameters. It is shown that an average clamping stiffness can be predicted from the Fractal surface parameters, or directly and more accurately from the static model of the clamped part. [ABSTRACT FROM AUTHOR]

The microstructural changes in food materials during the baking process directly influence their micromechanical properties and, thus, the strength of the solid walls. Baking time, as one of the vital variables, impacts the microstructural and micromechanical characteristics, alters the texture, and affects customer satisfaction. This research aims to investigate the alteration in three critical micromechanical properties: hardness, stiffness, and Young's modulus, as a function of moisture content during baking of cookies in an oven set at 185 ± 1 °C in the range of 10 to 60-min. The nanoindentation method, which involves pushing a nanoindenter into and removing it from cookie samples to measure the force-displacement data, was employed to measure the micromechanical properties. The results indicated that all the micromechanical properties initially increased when the moisture content decreased from 12.26 to 8.53 g/100 g solids and showed fluctuating trends at the later moisture content values. Throughout the baking process, the moisture content ranges from 2.71 to 12.26 g/100 g solids. Simultaneously, hardness varies from 0.28 to 0.88 GPa, stiffness ranges between 9.77 and 20.16 µN/nm, and Young's modulus experiences minimum and maximum values of 4.34 and 14.55 GPa, respectively. Finally, the Analysis of Variance and Duncan's multiple range tests revealed a significant difference between the mean values of some data points of hardness, stiffness, and Young's modulus as a function of moisture content. [ABSTRACT FROM AUTHOR]

Background The prognostic significance of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC) remains controversial. Notably, there is evidence suggesting an association between tissue stiffness and the aggressiveness of the disease. We therefore aimed to explore the effect of tissue stiffness on LNM-related invasiveness in PTC patients. Method A total of 2492 PTC patients from 3 hospitals were divided into an LNM group and a non-LNM group based on their pathological results. The effects of interior lesion stiffness (E) and peri-cancerous tissue stiffness (Eshell) on the LNM-related recurrence rate and mortality in each patient with PTC subgroup were analyzed. The activation of cancer-associated fibroblasts (CAFs) and extracellular matrix component type 1 collagen (COL-I) in the lesion were compared and analyzed across different subgroups. The underlying biological basis of differences in each subgroup was identified using RNA sequencing (RNA-seq) data. Results The Eshell value and Eshell/E in the LNM group were significantly higher than those in the non-LNM group of patients with PTC (Eshell: 72.72 ± 5.63 vs 66.05 ± 4.46; Eshell/E: 1.20 ± 1.72 vs 1.09 ± 1.10, P  < .001). When Eshell/E > 1.412 and LNM were both present, the recurrence rate and mortality were significantly increased compared to those of group of patients with LNM (91.67% and 7.29%, respectively). The CAF activation and COL-I content in the Eshell/E+ group were significantly higher than those in the Eshell/E− group (all P  < .001), and the RNA-seq results revealed significant extracellular matrix (ECM) remodeling in the LNM-Eshell/E+ group. Conclusions Stiff peri-cancerous tissue induced CAF activation, COL-I deposition, and ECM remodeling, resulting in a poor prognosis for PTC patients with LNM. [ABSTRACT FROM AUTHOR]

Identifying plastic hinge property is one of key the factors in successful modeling and subsequent seismic performance evaluation of precast concrete (PC) moment frame systems. Tight mechanical splices are also essentially required in precast connections, and its residual slip can greatly affect the plastic hinge length and finally the emulative performance level of PC seismic forceresisting system (SFRS). However, most of the existing models are not directly applicable in current forms to estimate the plastic hinge length of precast connections with mechanical splices. To address the effects of the residual slip induced in the mechanically spliced reinforcement system and its nonuniform stiffness due to splicing device (or coupler), a detailed nonlinear finite element (FE) analysis model was developed in this study, where plasticity-based constitutive models and a unique connector element were adopted for concrete and mechanically spliced reinforcements, respectively. Existing test results of column-foundation connections were used to verify the analytical approach. On this basis, a robust macro modeling method was also proposed for nonlinear cyclic analysis of PC moment frame systems with mechanical splices in this study. It appears that the magnitude of the residual slip in mechanical splices can greatly undermine the lateral stiffness, energy dissipation capacity, and equivalent viscous damping ratio of PC moment connections, and the proposed macro modeling approach can reasonably capture their behavioral characteristics. [ABSTRACT FROM AUTHOR]

Background: MR elastography (MRE) may provide quantitative imaging biomarkers of lumbar back muscles (LBMs), complementing MRI in spinal diseases by assessing muscle mechanical properties. However, reproducibility analyses for MRE of LBM are lacking. Purpose: To assess technical failure, within‐day and inter‐day reproducibility, robustness with the excitation source positioning, and inter‐observer agreement of MRE of muscles. Study Type: Prospective. Subjects: Seventeen healthy subjects (mean age 28 ± 4 years; 11 females). Field Strength/Sequence: 1.5 T, gradient‐echo MRE, T1‐weighted turbo spin echo. Assessment: The pneumatic driver was centered at L3 level. Four MRE were performed during two visits, 2–4 weeks apart, each consisting of two MRE with less than 10 minutes inter‐scan interval. At Visit 1, after the first MRE, the coil and driver were removed, then reinstalled. The MRE was repeated. At Visit 2, following the first MRE, only the driver was moved down 5 cm. The MRE was repeated. Two radiologists segmented the multifidus and erector spinae muscles. Statistical Tests: Paired t‐test, analysis of variance, intraclass correlation coefficients (ICCs). P‐values <0.05 were considered statistically significant. Results: Mean stiffness of LBM ranged from 1.44 to 1.60 kPa. Mean technical failure rate was 2.5%. Inter‐observer agreement was excellent (ICC ranging from 0.82 [0.64–0.96] to 0.99 [0.98–0.99] in the multifidus, and from 0.85 [0.69–0.92] to 0.99 [0.97–0.99] in the erector spinae muscles). Within‐day reproducibility was fair in the multifidus (ICC: 0.53 [0.47–0.77]) and good in the erector spinae muscles (ICC: 0.74 [0.48–0.88]). Reproducibility after moving the driver was excellent in both multifidus (ICC: 0.85 [0.69–0.93]) and erector spinae muscles (ICC: 0.84 [0.67–0.92]). Inter‐day reproducibility was excellent in the multifidus (ICC: 0.76 [0.48–0.89]) and poor in the erector spinae muscles (ICC: 0.23 [−0.61 to 0.63]). Data Conclusion: MRE of LBM provides measurements of stiffness with fair to excellent reproducibility and excellent inter‐observer agreement. However, inter‐day reproducibility in the multifidus muscles indicated that the herein used MRE protocol may not be optimal for this muscle. Evidence Level: 2 Technical Efficacy: Stage 1 [ABSTRACT FROM AUTHOR]

A numerical search approach is used to design high-order diagonally implicit Runge-Kutta (DIRK) time stepping schemes equipped with embedded error estimators, some of which have identical diagonal elements (i.e., SDIRK) and explicit first stage (i.e., ESDIRK). In each of these classes, we present new A-stable schemes of order six (the highest order of previously known A-stable DIRK-type schemes) up to order eight. For each order, we include one scheme that is only A-stable as well as several schemes that are L-stable, stiffly accurate, and/or have stage order two. The latter types require more stages, but yield better convergence rates for differential-algebraic equations (DAEs), and particularly those which have stage order two result in better accuracy for moderately stiff problems. The development of the eighth-order schemes requires, in addition to imposing A-stability, finding highly accurate numerical solutions for a system of 200 equations in over 100 variables, which is accomplished via a combination of global and local optimization strategies. The accuracy, stability, and adaptive stepsize control of the schemes are demonstrated on diverse problems. [ABSTRACT FROM AUTHOR]

We examined the integrity of flash-frozen and cryo-sectioned cardiac muscle preparations (introduced by Feng and Jin, 2020) by assessing tension transients in response to sinusoidal length changes at varying frequencies (1–100 Hz) at 25 °C. Using 70-μm-thick sections, we isolated fiber preparations to study cross-bridge (CB) kinetics: preparations were activated by saturating Ca2+ as well as varying concentrations of ATP and phosphate (Pi). Our results showed that, compared to ordinary skinned fibers, in-series stiffness decreased to 1/2, which resulted in a decrease of isometric tension to 62%, but CB kinetics and Ca2+ sensitivity were little affected. The pCa study demonstrated that the rate constant of the force generation step (2πb) is proportionate to [Ca2+] at < 5 μM, suggesting that the activation mechanism can be described by a simple second order reaction. We also found that tension, stiffness, and magnitude parameters are related to [Ca2+] by the Hill equation, with a cooperativity coefficient of 4–5, which is consistent with the fact that Ca2+ activation mechanisms involve cooperative multimolecular interactions. Our results support the long-held hypothesis that Process C (Phase 2) represents the CB detachment step, and Process B (Phase 3) represents the force generation step. Moreover, we discovered that constant H may represent the work-performing step in cardiac preparations. Our experiments demonstrate excellent CB kinetics with two well-defined exponentials that can be more distinguished than those found using ordinary skinned fibers. Flash-frozen and cryo-sectioned preparations are especially suitable for multi-institutional collaborations nationally and internationally because of their ease of transportation. [ABSTRACT FROM AUTHOR]

This paper presents a study on strengthening infill walls using composite materials to enhance shear capacity. The cementitious matrix-grid (CMG) material was employed for this purpose. Various configurations of the CMG, including single or double layers, applied to one or both sides of the wall, with or without anchorage, were tested. The study consisted of two stages. Initially, the mechanical properties of the bricks, mortar, and CMG mortar were determined using twenty-seven specimens. In the second stage, ten specimens, divided into five groups with one group left unstrengthened, underwent shear tests. Shear strength and shear strain relationships were determined for each specimen. Comparative analysis between strengthened and unstrengthened specimens revealed the effectiveness of the strengthening technique. The strengthened specimens exhibited superior structural performance compared to the control specimens. Specifically, the average maximum shear strength of all strengthened specimens surpassed that of the controls. Moreover, double-layer strengthening notably improved ductility. The findings suggest that applying a double layer of CMG to both sides of the wall with anchorage is the most effective method for strengthening. CMG composites significantly enhance the shear strength of infill walls and promote ductile failure. The comparisons of different strengthening combinations can contribute significantly to the existing literature and the construction sector by offering retrofitting options that can be tailored to address various economic and temporal, as well as target strengthening considerations. [ABSTRACT FROM AUTHOR]

Mechanical properties of tissues including their stiffness change throughout our lives, during both healthy development but also during chronic diseases like cancer. How changes to stiffness, occurring during cancer progression, impact leukocytes is unknown. To address this, myeloid phenotypes resulting from mono- and cancer co-cultures of primary murine and human myeloid cells on 2D and 3D hydrogels with varying stiffnesses were analyzed. On soft hydrogels, conventional DCs (cDCs) developed, whereas on stiff hydrogels plasmacytoid DCs (pDCs) developed. Soft substrates promoted T cell proliferation and activation, while phagocytosis was increased on stiffer substrates. Cell populations expressing macrophage markers CD14, Ly6C, and CD16 also increased on stiff hydrogels. In cancer co--cultures, CD86+ populations decreased on higher stiffnesses across four different cancer types. High stiffness also led to increased vascular endothelial growth factor A (VEGFA), matrix metalloproteinases (MMP) and CD206 expression; 'M2' markers expressed by tumor--associated macrophages (TAMs). Indeed, the majority of CD11c+ cells expressed CD206 across human cancer models. Targeting the PI3K/Akt pathway led to a decrease in CD206+ cells in murine cultures only, while human CD86+ cells increased. Increased stiffness in cancer could, thus, lead to the dysregulation of infiltrating myeloid cells and shift their phenotypes towards a M2--like TAM phenotype, thereby actively enabling tumor progression. Additionally, stiffness--dependent intracellular signaling appears extremely cell context--dependent, potentially contributing to the high failure rate of clinical trials. [ABSTRACT FROM AUTHOR]

AbstractSensitive marine clays (SMCs) often pose considerable problems in the construction of embankments for transportation structures. In this study, extensive mechanical, microstructural, and monitoring experiments were carried out to evaluate the evolution of mechanical properties of SMCs stabilized via Deep Mixing Method. The results indicate that unconfined compressive strength and secant modulus increase with curing time. A significant improvement in mechanical properties is observed at early ages. Higher binder contents produce higher mechanical properties after same curing period. However, excess binder content does not provide significant improvement effects. The addition of ground granulated blast furnace slag (GGBFS) results in higher mechanical properties after long-term curing, and the enhancing degree is more evident with a higher proportion of GGBFS. But the situations are reversed at young age due to the “retarding effect” of GGBFS. These observations are also supported by results of physical properties, mercury instruction porosimetry, suction monitoring, and X-ray diffraction analyses. In addition, predictive models are established based on elastic-plastic theory and binder hydration model. The developed models are implemented in COMSOL Multiphysics and validated against experimental results. A good agreement is observed between experimental and predicted results which confirms the ability of developed models to predict the mechanical characteristics. [ABSTRACT FROM AUTHOR]

The heterogeneity of natural rocks complicates the study of carbon sequestration within these materials and raises concerns about the reproducibility of experimental results. Consequently, identifying appropriate rock-like materials has become critical. This research examined the impact of various factors—humidity, binder content, curing period, and cold pressure—on the bond strength of magnesium oxychloride cement (MOC) through orthogonal testing. The tests utilized a molar ratio of MgO to MgCl2-6H2O to H2O of 7:1:18. Both X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze the hydration reactions of MOC and to explore the correlation between the microstructure of the SiO2-MgO-MgCl2 system and its bonding characteristics. The findings indicated that a 5% relative humidity enhances the 7-day bond strength of MOC. Moreover, increasing the curing humidity to 60% relative humidity supports the ongoing hydration of the strength-contributing phases. A binder content ranging from 15% to 25% proved optimal, yielding samples with superior strength and stiffness. While cold pressing initially enhances the bonding properties of MOC, solution loss during the process adversely affects its long-term bonding characteristics. From a mechanical standpoint, the silica-magnesium oxide-magnesium chloride system demonstrates exceptional early strength and resilience, positioning it as a promising rock-like material system. [ABSTRACT FROM AUTHOR]

Background: Stalk lodging (the premature breaking of plant stalks or stems prior to harvest) is a persistent agricultural problem that causes billions of dollars in lost yield every year. Three-point bending tests, and rind puncture tests are common biomechanical measurements utilized to investigate crops susceptibility to lodging. However, the effect of testing rate on these biomechanical measurements is not well understood. In general, biological specimens (including plant stems) are well known to exhibit viscoelastic mechanical properties, thus their mechanical response is dependent upon the rate at which they are deflected. However, there is very little information in the literature regarding the effect of testing rate (aka displacement rate) on flexural stiffness, bending strength and rind puncture measurements of plant stems. Results: Fully mature and senesced maize stems and wheat stems were tested in three-point bending at various rates. Maize stems were also subjected to rind penetration tests at various rates. Testing rate had a small effect on flexural stiffness and bending strength calculations obtained from three-point bending tests. Rind puncture measurements exhibited strong rate dependent effects. As puncture rate increased, puncture force decreased. This was unexpected as viscoelastic materials typically show an increase in resistive force when rate is increased. Conclusions: Testing rate influenced three-point bending test results and rind puncture measurements of fully mature and dry plant stems. In green stems these effects are expected to be even larger. When conducting biomechanical tests of plant stems it is important to utilize consistent span lengths and displacement rates within a study. Ideally samples should be tested at a rate similar to what they would experience in-vivo. [ABSTRACT FROM AUTHOR]

This study evaluates the laboratory performance of Warm-Mix Asphalt (WMA) containing locally sourced Steel Slag (SS) and limestone (LS), focusing on stiffness and moisture sensitivity. Four asphalt mixes were tested: Hot mix with limestone (HL), hot mix with steel slag (HS), warm mix with limestone (WL), and warm mix with steel slag (WS). The binder used for all mixes was AC 60/70 penetration grade, and Aspha-min served as the warm mix additive. Testing included Marshall Stability, boiling water, indirect tensile strength, moisture-induced damage (TSR), and dynamic modulus. Image Analysis quantified the aggregate-retained coated area after the boiling test. Despite performance differences, all mixes met Egyptian code requirements for asphalt concrete mixes. Visual inspection and image analysis demonstrated the effectiveness of using steel slag to mitigate asphalt mix stripping. The retained coated area for limestone mixes ranged from 60 % to 75 %, while SS mixes exhibited over 95 %. Dynamic modulus tests indicated no significant stiffness difference with SS, and stability increased by 8 % and 14 % with and without the warm additive. Economic study confirmed the feasibility of utilizing SS. In conclusion, combining Aspha-Min and steel slag improves AC mix production and construction processes, offering a sustainable and advantageous option in Egypt. [ABSTRACT FROM AUTHOR]

Suppressing the vibration of cable-driven parallel mechanisms (CDPMs) is of great significance for improving their performance such as positioning accuracy. In this paper, a hybrid vibration suppression strategy based on stiffness enhancement and input shaping is proposed to reduce the vibration of a CDPM in the process of moving. Firstly, the stiffness model and vibration model of the CDPM are established. Then, based on the stiffness model and the vector set λ that meets the requirements of the cable tensions, a stiffness enhancement algorithm is proposed to improve the stiffness of the mechanism by adjusting cable tensions. In order to reduce the vibration of the mechanism to the maximum extent, a hybrid vibration suppression strategy is proposed by combining the stiffness enhancement algorithm with the multi-modal input shaping technique. Finally, the effect of stiffness enhancement algorithm and hybrid vibration suppression strategy on reducing mechanism vibration is verified by experiments. The hybrid vibration suppression strategy proposed in this paper does not require additional components and therefore does not increase the cost of vibration suppression, and it has good performance. [ABSTRACT FROM AUTHOR]

Antifibrotic drug screening requires evaluating the inhibitory effects of drug candidates on fibrotic cells while minimizing any adverse effects on normal cells. It is challenging to create organ-specific vascularized organoids that accurately model fibrotic and normal tissues for drug screening. Our previous studies have established methods for culturing primary microvessels and epithelial cells from adult tissues. In this proof-of-concept study, we used rats as a model organism to create a two-dimensional vascularized liver organoid model that comprised primary microvessels, epithelia, and stellate cells from adult livers. To provide appropriate substrates for cell culture, we engineered ECMs with defined stiffness to mimic the different stages of fibrotic tissues and normal tissues. We examined the effects of two TGFβ signaling inhibitors, A83-01 and pirfenidone, on the vascularized liver organoids on the stiff and soft ECMs. We found that A83-01 inhibited fibrotic markers while promoting epithelial genes of hepatocytes and cholangiocytes. However, it inhibited microvascular genes on soft ECM, indicating a detrimental effect on normal tissues. Furthermore, A83-01 significantly promoted the expression of markers of stem cells and cancers, increasing the potential risk of it being a carcinogen. In contrast, pirfenidone, an FDA-approved compound for antifibrotic treatments, did not significantly affect all the genes examined on soft ECM. Although pirfenidone had minor effects on most genes, it did reduce the expression of collagens, the major components of fibrotic tissues. These results explain why pirfenidone can slow fibrosis progression with minor side effects in clinical trials. In conclusion, our study presents a method for creating vascularized liver organoids that can accurately mimic fibrotic and normal tissues for drug screening. Our findings provide valuable insights into the potential risks and benefits of using A83-01 and pirfenidone as antifibrotic drugs. This method can be applied to other organs to create organ-specific vascularized organoids for drug development. [ABSTRACT FROM AUTHOR]

Among infrastructure, concrete bridges are the most exposed to various environmental effects. Structural degradation occurs due to natural and artificial influences shortening the lifespan of the structure. Therefore, bridges need to be reinforced over time. The structures used in this study are re-formed using aged bridge floor decks that have been used for 50 years, approximately. The fiber-reinforced polymer (FRP) adhesion method, using sheets and plate forms, was selected among various reinforcement methods to investigate the performance of reinforced structures. We have tested various reinforcement scenarios including one and two layers FRP sheets and FRP plates. The mechanical properties of the reinforced structures were evaluated experimentally through tensile strength and flexural test experiments. In contrast to most available literature focused on model-based studies, our present work represents an experimental test validation of structural reinforcement on an actual bridge. Our results indicate that fiber-based reinforcement in sheet form exhibits higher performances of the reinforced structure compared to reinforcement using the plate form. This study is intended to provide sufficient data for reinforcing bridge floors that could be used for reference at future construction sites. [ABSTRACT FROM AUTHOR]

Individuals with neuromuscular pathologies are often prescribed an ankle-foot orthosis (AFO) to improve their gait mechanics by decreasing pathological movements of the ankle and lower limb. AFOs can resist or assist excessive or absent muscular forces that lead to tripping, instability, and slow inefficient gait. However, selecting the appropriate AFO with mechanical characteristics, which limit pathological ankle motion in certain phases of the gait cycle while facilitating effective ankle movement during other phases, requires careful clinical decision-making. The aim of this study is to propose an explicit methodology for the adjustment of multi-function articulated AFOs in clinical settings. A secondary aim is to outline the evidence supporting this methodology and to identify gaps in the literature as potential areas for future research. An emerging class of AFO, the multi-function articulated AFO, offers features that permit more comprehensive, iterative, and reversible adjustments of AFO ankle alignment and resistance to ankle motion. However, no standard method exists for the application and optimization of these therapeutic devices in the clinical setting. Here we propose an evidence-guided methodology applicable to the adjustment of multi-function articulated AFOs in the clinical setting. Characteristic load-deflection curves are given to illustrate the idealized yet complex resistance-angle behavior of multi-function articulated AFOs. Research is cited to demonstrate how these mechanical characteristics can help mitigate specific pathologic ankle and knee kinematics and kinetics. Evidence is presented to support the effects of systematic adjustment of high resistance, alignable, articulated AFOs to address many typical pathomechanical patterns observed in individuals with neuromuscular disorders. The published evidence supporting most decision points of the algorithm is presented with identified gaps in the evidence. In addition, two hypothetical case examples are given to illustrate the application of the method in optimizing multi-function articulated AFOs for treating specific gait pathomechanics. This method is proposed as an evidence-guided systematic approach for the adjustment of multi-function articulated AFOs. It utilizes observed gait deviations mapped to specific changes in AFO alignment and resistance settings as a clinical tool in orthotic treatment for individuals with complex neuromuscular gait disorders. [ABSTRACT FROM AUTHOR]

Background: Manipulation under anesthesia (MUA) is a well-established treatment for stiffness after total knee arthroplasty (TKA). Risk factors for failure of MUA remain largely unknown. The primary aim of this study was to identify risk factors for failure of MUA after TKA. Methods: We performed a retrospective cohort study including 470 patients who underwent MUA after primary TKA with minimum 2 year follow-up. Patients were grouped into success (n = 412) or failure (n = 58) cohorts; failure was defined as flexion < 90° at most recent follow-up or revision for stiffness. The increase in flexion post-MUA for the cohort was calculated. Several clinical, patient, and surgical factors were analyzed using univariate, followed by multivariable logistic regression models to identify independent risk factors associated with failure. Results: The mean increase in flexion was 42° (range 0–115). BMI 30–35 (p = 0.01, odds ratio (OR) 2.42; 95% CI 1.25–4.68) and poorer pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.23–1.67) were risk factors for failure. When considering revision for stiffness only, BMI 30–35 (p = 0.01, OR 3.27; 95% CI 1.41–7.61), lower pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.18–1.75), and history of prior knee surgery (p = 0.04, OR 2.31; 95% CI 1.06–5.04) were predictors of failure. Time to MUA (p = 0.48), thromboprophylaxis (p = 0.44), pre-operative opioid use (p = 0.34), depression/anxiety (p = 1.0), and several other factors analyzed were not associated with failure. Conclusion: In this large cohort, elevated BMI and lower pre-MUA flexion were risk factors for failure of MUA. History of prior knee surgery was an additional predictor of requiring revision for stiffness. [ABSTRACT FROM AUTHOR]

In order to determine the service life of wind turbine blades (WTB) and extend their service life, a life extension assessment model for WTB is proposed based on support vector regression (SVR) considering stiffness degradation. First, the advantages of stiffness performance indexes are selected to assess the life of in-service blades. The stiffness degradation rule is studied about turbine blade. Furthermore, the relationship between WTB life and stiffness is discussed to clarify the factors of the life extension model. Based on stiffness indicator, the support vector regression algorithm (SVR) is used to establish a life extension assessment model for WTB. Particle swarm optimization (PSO) is used to optimize the model parameters. The optimized model is trained and validated using WTB degradation stiffness data. Finally, the results show that the proposed model is effective in life extension assessment of WTB. The model with radial basis as the kernel function has a high goodness of fit. [ABSTRACT FROM AUTHOR]

Introduction: Ixekizumab, an interleukin 17A (IL-17A) inhibitor, has demonstrated rapid and sustained improvement in the signs and symptoms in patients with active radiographic axial spondyloarthritis (r-axSpA) in global and Chinese populations. We studied the effect of ixekizumab on patient-reported outcomes (PROs) (including patient global, spinal pain, stiffness, and fatigue) and overall health-related quality of life (HRQoL) of ixekizumab in the phase 3 study in China. Methods: In this Chinese phase 3, randomized, double-blind, placebo-controlled study, patients with r-axSpA were randomized (1:1) to receive ixekizumab 80 mg every 4 weeks (IXEQ4W; starting dose 160 mg) or placebo for 16 weeks. At week 16, patients receiving placebo were switched to IXEQ4W, and those receiving IXEQ4W continued, until week 52. Data for patient global, spinal pain, spinal pain at night, stiffness, and fatigue were collected through week 52. Minimally clinical important differences (MCIDs) were determined for spinal pain and spinal pain at night. The subgroup analyses by baseline disease duration since diagnosis and baseline C-reactive protein (CRP) level were conducted post hoc. Results: Compared with placebo, patients treated with IXEQ4W reported significantly greater improvement with a rapid onset in changes from baseline of PROs (patient global, spinal pain, spinal pain at night, stiffness, and fatigue) through week 16. Improvements were maintained through week 52. A similar trend of improvement was also observed in MCID response in spinal pain and spinal pain at night. The improvement in overall HRQoL was supported by EQ-5D-5L assessment. Subgroup analyses demonstrated that IXEQ4W provided significantly greater efficacy at week 16 compared with placebo, irrespective of baseline disease duration or baseline CRP level. Conclusion: IXEQ4W provided rapid and sustained improvement in clinically relevant PROs and overall HRQoL through 1-year treatment in Chinese patients with r-axSpA. Regardless of the baseline disease duration or baseline CRP level, consistent efficacy was observed. Trial Registration: ClinicalTrials.gov identifier NCT04285229. [ABSTRACT FROM AUTHOR]

The aim of the current study is to provide evidence regarding the influence of particle size on the dynamic properties in granular materials. Experiments using a resonant column (RC) device were conducted on glass beads having similar coefficient of uniformity, but four different mean grain sizes to describe the tendencies in the magnitude of Gmax and Emax. It can be clearly seen that for similar particle gradation the influence of particle size is significant, in particular for larger mean grain sizes d50 exceeding 1·5 mm. The experimental data were fitted using existing empirical relationships with corresponding fitting parameters. The fitting parameters describing the void ratio and pressure dependence to estimate maximum stiffness were found to depend on grain size to a certain extent. This influence was diminished for the materials with a d50 < 1·5 mm. It was therefore possible to use a unique set of fitting parameters for these materials with a satisfying degree of accuracy. The results were compared with some previous studies to highlight the size dependency of Gmax and Emax for materials with mean size greater than 2 mm, but also the relatively small influence on materials with lower mean particle sizes (d50 < 2 mm) is acknowledged. The results are furthermore discussed through a micromechanical interpretation highlighting why larger grain sizes influence stiffness values. [ABSTRACT FROM AUTHOR]

The current asphalt pavement design method instituted in Brazil, MeDiNa, requires tests to determine the parameters of resilient modulus and permanent deformation of the granular layers. As these tests have a long execution time and high cost, this study analysed the variation of the resilient modulus (using composite model tested and linear predicted values) of low-volume road subgrade and the impact on the pavement design. This study simulated four different subgrades considering the soils of the metropolitan region of Fortaleza, Ceara, north-eastern Brazil and three predefined pavement structures. Total and subgrade rutting provided by the MeDiNa software were used as evaluation parameters. The simulation results allowed the authors to verify that the calculated rutting values are very close despite the resilient modulus adopted. In conclusion, road designers can consider any predicted linear value of the resilient modulus or composite models in the design of these highways, even with forecast errors greater than 20%. The study also proposes a low-volume road design catalogue considering the subgrades analysed. [ABSTRACT FROM AUTHOR]

This paper investigates the behaviors of different types of prestressed concrete beams utilizing fully encased cold‐ or hot‐formed steel joists. Twelve types divided into two sets of composite beams are assessed. Set 1 is composed of six beams utilizing cold‐formed steel (CFS) joists distinguished by the cross‐sectional steel‐to‐concrete ratios of 1%, 2%, and 3%, and the presence or absence of web openings. Set 2 has the similar composition but utilizes hot‐formed steel joists. Four‐point and three‐point bending tests were conducted at the mid‐span of the composite concrete beams. Key properties, such as strength, stiffness, flexural load capacity, ductility, energy absorption capacity, and failure modes, were used in the analysis. It was found that the specimens with CFS I‐beam joists provided better performance compared to those with hot‐formed steel joists. Also, the existence of web openings in the encased CFS beams enhances the ductility and energy absorption of the composite concrete beams. [ABSTRACT FROM AUTHOR]

Mechanical soil parameters are not constants and can be defined in various ways. Therefore, determination of their values for engineering practice is difficult. This problem is discussed based on results of piezoceramic element tests and triaxial tests (unconfined and confined) on loess specimens improved by compaction and sand admixture (20% by weight). The study indicated also the effectiveness of this simple method of loess stabilization. The influence of specimen size, draining conditions, stress and strain state, and different calculation methods on the evaluation of basic mechanical parameters were analyzed. The initial shear and Young's moduli, the degradation of secant moduli with strain, tangent moduli, and Poisson' ratio were determined. The results showed that the shear strength parameters are much less sensitive to the test variables than the stiffness parameters are. In triaxial tests, the strength criterion adopted, the sample size, and the drainage conditions influenced the measured value of cohesion, with a much smaller impact on the angle of internal friction. On the other hand, the adopted definition of the parameter and the range of strains had the greatest influence on the value of the stiffness modulus. Moreover, larger specimens were usually found to be stiffer. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic, inflammatory systemic disorder of synovial joints and results in polyarthritis, chronical degeneration, and finally deformities and ankylosis in severe cases. Synovitis and pannus formation are results of inflammatory changes and lead into restriction in joint movement. Shoulders are among the later affected and larger joints and formation of synovitis in early active stages and pannus in later stages might be concluded with frozen shoulder and severe impairment in functionality. These late-term changes cannot be controlled with systemic or local anti-inflammatory agents and synovectomy is chosen in some cases. However, the results are not satisfactory and recurrence is common. In this case report, we presented a case of RA with severe shoulder pain, restricted movement due to synovial hypertrophy, and pannus formation which are resistant to local and systemic interventions and not suitable for surgical or chemical synovectomy. Microwave ablation (MWA) was performed successfully without any complication and she well responded in terms of DAS-28, functional, and pain scores. Range of motion and funcitonal restriction were recovered. This case report describes the use and promising results of MWA in RA with severe synovial hypertrophy and pannus formation even in the absence of active arthritis and effusion. MWA is a safe and minimally invasive technique that can be easily performed in coordinance of rheumatologists and interventional radiologists in proper cases. [ABSTRACT FROM AUTHOR]

The development of tests, standards, and specifications necessitates the establishment of technical validity while concurrently optimizing costs associated with the testing requirements. AASHTO TP 125-16 recommends the utilization of the bending beam rheometer (BBR) as a simple, rapid, relatively cost-effective, and reproducible method for assessing the low-temperature properties of asphalt concrete mixtures. However, the standard does not provide specific guidance regarding the representative sample size necessary for the BBR test. Therefore, this study used statistical techniques to calculate the sample size by scrutinizing data for two variables, i.e., creep moduli (stiffness) and stress relaxation capacity (m -value), which were obtained from testing a variety of asphalt concrete mixtures. In this regard, distinct asphalt mixtures were meticulously prepared and subjected to laboratory testing. A representative sample size of eight thin-beam specimens was determined. This recommendation was validated by sampling five different asphalt mixtures from pavement construction projects. It was found that testing and analyzing trimmed means of only eight specimens from a 2 in. thick asphalt concrete layer was adequate to represent the global low-temperature performance of those five pavement sections. So, an asphalt mixture's low-temperature performance can be completed in 2 h by testing only eight specimens in the BBR without sacrificing accuracy and practicality. Therefore, this study contributes to a possible application of the BBR during pavement construction. [ABSTRACT FROM AUTHOR]

Background: The rare nature of dystrophic and non-dystrophic myotonia has limited the available evidence on the efficacy of mexiletine as a potential treatment. To address this gap, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of mexiletine for both dystrophic and non-dystrophic myotonic patients. Methods: The search was conducted on various electronic databases up to March 2023, for randomized clinical trials (RCTs) comparing mexiletine versus placebo in myotonic patients. A risk of bias assessment was carried out, and relevant data was extracted manually into an online sheet. RevMan software (version 5.4) was employed for analysis. Results: A total of five studies, comprising 186 patients, were included in the meta-analysis. Our findings showed that mexiletine was significantly more effective than placebo in improving stiffness score (SMD = − 1.19, 95% CI [− 1.53, − 0.85]), as well as in reducing hand grip myotonia (MD = − 1.36 s, 95% CI [− 1.83, − 0.89]). Mexiletine also significantly improved SF-36 Physical and Mental Component Score in patients with non-dystrophic myotonia only. Regarding safety, mexiletine did not significantly alter ECG parameters but was associated with greater gastrointestinal symptoms (GIT) compared to placebo (RR 3.7, 95% CI [1.79, 7.64]). Other adverse events showed no significant differences. Conclusion: The results support that mexiletine is effective and safe in myotonic patients; however, it is associated with a higher risk of GIT symptoms. Due to the scarcity of published RCTs and the prevalence of GIT symptoms, we recommend further well-designed RCTs testing various drug combinations to reduce GIT symptoms. [ABSTRACT FROM AUTHOR]

Purpose: Our study aims to evaluate differences in muscle parameters of the quadriceps muscles in patients with knee osteoarthritis (KOA) in older adults. Methods: The study included 40 patients diagnosed with unilateral knee osteoarthritis in the KOA group (KG) and 40 asymptomatic elderly individuals in the control group (CG). Muscle ultrasonic mean echo intensity and shear modulus, as well as tone and stiffness of the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) were analyzed. Additionally, clinical correlations were performed. Results: In the KG group, there were significant differences in echo intensity, shear modulus, and tone between the affected and unaffected sides for RF (p=0.003, 0.019, 0.014), while VM showed significant differences in shear modulus and tone (p=0.006, 0.002). Additionally, VL exhibited significant differences in echo intensity, shear modulus, and stiffness (p=0.007, 0.006, 0.010). Compared to the CG group, the KG group showed significant differences in echo intensity of the affected side RF (p=0.001). VM exhibited statistically significant differences in echo intensity and shear modulus (p < 0.001, p=0.008), while VL showed statistically significant differences in echo intensity, tone, and stiffness (p < 0.001, p=0.028, p < 0.001). The correlation results showed that patients with unilateral KOA, VM, and VL echo intensity were correlated with K-L grade (r = 0.443, p=0.004; r = 0.469, p=0.002). The tone of VL was correlated with VAS and WOMAC (r = 0.327, p=0.039; r = 0.344, p=0.030). Conclusion: The parameters of the quadriceps femoris muscle exhibit asymmetry between the affected and unaffected sides in patients with unilateral KOA, as well as a difference between the dominant side of healthy older individuals and the affected side of KOA. [ABSTRACT FROM AUTHOR]

Monopiles serve as the foundational support for offshore wind turbines and are constructed as large, hollow, and rigid steel pipes. Given their offshore installation, these foundations experience cyclic lateral forces from wind and waves. This paper focuses on investigating the cyclic lateral capacity of monopiles through experimental and numerical analysis. The study examines varying factors such as slenderness (L/D) ratios of 2, 4, and 6, load amplitudes (ξb) of 40%, 30%, and 20%, and different densities of sand (RD) at 35%, 55%, and 75%. One-way cyclic loading at a frequency of 0.25 Hz was applied during the experiments using a pneumatic cylinder setup to the model piles. Numerical analysis was conducted on the prototype piles using PLAXIS 3D finite element software. The analysis utilised a hypoplastic model with an intergranular strain concept as the constitutive model. The model was validated against the experimental results of MLD2/LA40/RD55 and exhibited similar behaviour. The experimental findings indicate an initial 40% increase in stiffness during the first 10 cycles, leading to a higher accumulation of displacement. However, as the number of cycles increased, the rate of stiffness increase decreased due to soil getting dispersed around the pile, resulting in an increased rate of accumulated displacement. This behaviour was observed across various L/D ratios, load amplitudes, and soil densities. Additionally, an increase in load amplitude and L/D ratio, as well as a decrease in soil density, resulted in higher accumulated displacement and reduced stiffness. [ABSTRACT FROM AUTHOR]

One of the most crucial parameters in the field of machine tool engineering is the stiffness of the machine tool spindle, as it has a direct impact on the precision and accuracy of machining. This paper presents a research on the effects of geometric parameters of capillary tubes, including diameter (dc) and length (lc), on the stiffness of hydrostatic bearings in machine tools. The oil pump pressure in this study was set at a range from 3 MPa to 5 MPa. The simulation results demonstrate the relationship between the capillary geometric parameters, pressure, and the stiffness of the hydrostatic spindle unit. These findings indicate a direct relationship between stiffness and pump pressure, with increases in pressure also raising lubricant temperature, which may impair cooling. The shape of the capillary directly affects the ratio of oil chamber pressure to pump pressure, which in turn affects hardness. The results of the study indicate that for spindles in machine tools, a dc ranging from 0.3 mm to 0.6 mm and a (lc /dc) ratio of between 20 and 100 are feasible based on the given stiffness requirement. It is possible to select an appropriate set of capillary parameters to achieve the best stiffness with specific requirements under the working conditions of hydrostatic bearings based on the results of the simulation analysis. [ABSTRACT FROM AUTHOR]

The presence of atherosclerotic plaque vessels is a critical factor in plaque destabilization. This may be attributable to the leaky phenotype of these microvessels, although direct proof for this notion is lacking. In this study, we investigated molecular and cellular patterns of stable and hemorrhaged human plaque to identify novel drivers of intraplaque vessel dysfunction. From transcriptome data of a human atherosclerotic lesion cohort, we reconstructed a co-expression network, identifying a gene module strongly and selectively correlated with both plaque microvascular density and inflammation. Spectrin Beta Non-Erythrocytic 1 (sptbn1) was identified as one of the central hubs of this module (along with zeb1 and dock1) and was selected for further study based on its predominant endothelial expression. Silencing of sptbn1 enhanced leukocyte transmigration and vascular permeability in vitro, characterized by an increased number of focal adhesions and reduced junctional VE-cadherin. In vivo, sptbn1 knockdown in zebrafish impaired the development of the caudal vein plexus. Mechanistically, increased substrate stiffness was associated with sptbn1 downregulation in endothelial cells in vitro and in human vessels. Plaque SPTBN1 mRNA and protein expression were found to correlate with an enhanced presence of intraplaque hemorrhage and future cardiovascular disease (CVD) events during follow-up. In conclusion, we identify SPTBN1 as a central hub gene in a gene program correlating with plaque vascularisation. SPTBN1 was regulated by substrate stiffness in vitro while silencing blocked vascular development in vivo, and compromised barrier function in vitro. Together, SPTBN1 is identified as a new potential regulator of the leaky phenotype of atherosclerotic plaque microvessels. [ABSTRACT FROM AUTHOR]

The construction and maintenance of road infrastructure is required for the sustained economic growth of communities and societies. Nonetheless, these activities imply the tangible risk of boosting the depletion of non-renewable resources (e.g., aggregates and binders). A widely used strategy for preserving as much of these natural resources as possible is the design of high-performance composite materials. For instance, antistripping agents (ASAs) are employed to mitigate the loss of adhesive bonding between asphalt binders and aggregates, enhancing the mechanical behaviour of hot-mix asphalts (HMAs). There is still no consensus on the effectiveness of ASAs. In this regard, the present research aims to contribute to the literature by conducting a case study on the influence of three different ASAs (hydrated lime, an amines-based liquid additive, and a silanes-based liquid additive) on the moisture susceptibility, stiffness, and rutting resistance of HMA. For these purposes, indirect tensile strength, indirect tensile stiffness modulus, and uniaxial cyclic compression tests were carried out. Overall, the involved experimental protocol drew the main conclusion that the incorporation of hydrated lime as a mineral filler (at a content of 1.68% by dry weight of aggregates) is capable of improving the mechanical performance of HMAs through decreases in humidity sensitivity and permanent deformation, together with a slight increase in rigidity. [ABSTRACT FROM AUTHOR]

This study outlines a method of utilizing the finite element method and a simple mathematical model to predict the behavior of laminated veneer lumber (LVL) beams strengthened with composite sheets. The numerical models were created using the Abaqus 2017 software. The LVL was considered as a linearly elastic or elastic–plastic material, factoring in Hill's yield criterion. The composites were simulated as linearly elastic–ideally plastic materials. The mathematical models were predicated on the methodology of transformed cross-section. The theoretical and numerical outcomes were juxtaposed with previous empirical investigations. The comparison encompassed load-bearing capacity, stiffness, and deformation under peak force. Furthermore, presentations of normal stress maps in the LVL and composite have been illustrated. The derived maps were juxtaposed with the delineations of failure modes. An adequate correlation was identified between the theoretical, numerical, and empirical values in the case of beams reinforced with aramid, glass, and carbon sheets. The relative deviation varied from several to multiple percentages. This technique is not applicable for evaluating load-bearing capacity and deformation when only dealing with sheets with low elongation of rupture. This is a consequence of their premature failure. The proposed models may be utilized by researchers and engineers in the design of reinforcements for timber structures. [ABSTRACT FROM AUTHOR]

A theoretical model of the orifice-compensated air bearing with rectangular shape is built to study the stability, the stiffness and the air consumption considering the air film thickness. The study shows that, the pocket volume ratio of less than 0.03 is recommended to avoid the pneumatic hammer. The stability is good and the air consumption is small when the bearing has the high stiffness. Strict control of the structural deformation is crucial as it can significantly affect the stability. Increasing the nozzle number can improve the stability and avoid the choked flow. The findings are of great importance for the design of the orifice-compensated air bearing. [ABSTRACT FROM AUTHOR]

Mechanical properties of hydrate-bearing fine-grained sediments are crucial to effectively mitigate environmental risks caused by artificial and natural decomposition of natural gas hydrates, and the decomposition can induce laterally confined deformation. To explore the effect of natural gas hydrates on laterally confined compression properties, consolidation tests are conducted on remolded hydrate-free and hydrate-bearing samples by using natural fine-grained sediments collected from the northern South China Sea as the host sediments, and empirical equations are developed based on the analyses of consolidation characteristics. The results show that vertical loading induces a reduction in void ratio, and the reduction increases with decreasing hydrate saturation when samples are subjected to the same vertical stress change. The compression index of samples is about 0.53 whether there is hydrate or not, but the yield stress of samples increases sharply with increasing hydrate saturation once beyond the critical value. The coefficient of volume compression and the coefficient of consolidation of hydrate-bearing samples both increase firstly and then decrease to a relative stable level with increasing vertical stress, and the transition occurs at 200 kPa. The average consolidation degree with elapsed time increases rapidly under low vertical stresses, slowly under median vertical stresses, and under high vertical stresses, the consolidation increases a little faster but still slower than those under low vertical stresses. [ABSTRACT FROM AUTHOR]