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We explore the use of Fourier series to describe the kinematics of human running. From a database of 285 trials of treadmill running, we drive a musculoskeletal model with 104 anatomical joint angles to obtain kinematics. Using FFT analysis, we determine a fundamental frequency for all independent joint angles and compute average step kinematics. Finally, we represent the average step kinematics using Fourier series with numbers of coefficient pairs ranging from one through ten. We find that five or fewer Fourier coefficient pairs provide an accurate (Pearson's correlation > 0.99 and root mean square difference less then 0.5 degrees) representation for most joint angles. In conclusion, Fourier series appear to provide a compact and valid representation of running kinematics, thus enabling researchers to confidently use Fourier series in research of human running.Characterizing reactive stepping is important to describe the response's effectiveness. Timing of reactive step initiation, execution, and termination have been frequently reported to characterize reactive balance control. However, the test-retest reliabilities of these measures are unknown. Accordingly, the purpose of this study was to determine the between- and within-session test-retest reliabilities of various force plate-derived measures of reactive stepping. Nineteen young, healthy adults responded to 6 small (~8-10% of body weight) and 6 large perturbations (~13-15% of body weight) using an anterior lean-and-release system. Tests were conducted during two visits separated by at least two days. Participants were instructed to recover balance in as few steps as possible. Step onset, foot-off, swing, and restabilization times were extracted from force plates. Relative test-retest reliability was determined through intraclass correlation coefficients (ICCs) and 95% confidence intervals (CIs). Absolute test-retest reliability was assessed using the standard error of the measurement (SEM). Foot-off and swing times had the highest between- and within-session test-retest reliabilities regardless of perturbation size (between-session ICC = 0.898-0.942; within-session ICC = 0.455-0.753). Conversely, step onset and restabilization times had lower ICCs and wider CIs (between-session ICC = 0.495-0.825; within-session ICC = -0.040-0.174). Between-session test-retest reliability was higher (ICC = 0.495-0.942) for all measures than within-session test-retest reliability (ICC = -0.040-0.753). Time to restabilization had the highest SEM, indicating the worst absolute reliability of the measures. These findings suggest multiple baseline sessions are needed for measuring restabilization and step onset times. The minimal detectable changes reported provide an index for measuring meaningful change due to an intervention.Flatfoot is a risk factor for patellofemoral pain syndrome (PFPS), and excessive rearfoot eversion occurring in flatfoot has been associated with the development and progression of PFPS; however, the mechanism remains unclear. This study aimed to investigate transverse shank and frontal rearfoot coordination patterns and variability when running with normal foot and flatfoot. Participants with normal foot (n = 13) and flatfoot (n = 13) were asked to run at their preferred speed. The coupling angle between the shank and rearfoot, representing intersegmental coordination, was calculated using the modified vector coding technique and categorized into four coordination patterns. Standard deviation of the coupling angle was computed as a measure of coordination variability during the stance phase. No differences in the characteristics and spatiotemporal parameters between groups were found, and all participants had rearfoot strike pattern. During midstance, the flatfoot group showed a significantly greater proportion of anti-phase with proximal (shank) dominancy than the normal foot group (p = 0.04, effect size = 0.88 [large]). Furthermore, flatfoot group showed a significantly greater in variability than the normal foot group (p = 0.03, effect size = 0.91 [large]). This study's results may help explain why flatfoot is likely to result in PFPS. However, the occurrence mechanism of running injuries like PFPS is multi- factorial. Since these results alone are not sufficient to explain the cause-effect relationship between flatfoot and injuries like PFPS, a prospective study including other factors such as patellofemoral joint stress would also be needed.In this study, we aimed to explore the impact of previous history of lateral ankle sprain on the mechanical and viscoelastic properties of the tibialis anterior (TA), peroneus longus (PL) and gastrocnemius lateralis (GL) and medialis (GM) in asymptomatic men. For this purpose, a group of 26 men with previous history of lateral ankle sprain (ASG) and a control group (CG) of 29 healthy counter-parts participated in this study. Tone, stiffness, elasticity and mechanical stress relaxation time were measured using a myotonometer in a single session. Higher tone was noted for TA and GL in ASG as compared to CG (effect size of Cohen's d = 0.57 [p = 0.04] and 0.59 [p = 0.04], respectively). Further, stiffness was higher in ASG than in CG for TA (d = 0.56; p = 0.04), PL (d = 0.58; p = 0.04) and GL (d = 0.63; p = 0.02). Stress relaxation time was also lower for the ASG compared to the CG for TA (d = 0.61; p = 0.03), PL (d = 0.55; p = 0.04) and GL (d = 0.68; p = 0.02). There were no significant differences between groups in elasticity (p > 0.05). GM experienced no significant changes after ankle sprain in any of the variables (p > 0.05). To conclude, previous history of lateral ankle sprain results in higher TA and GL muscle tone. Likewise, these muscles in addition to PL exhibit less deformation against resistance due to their increased stiffness, thus needing a shorter time to restore to their original shape after deformation.Internal fixation by plate osteosynthesis is the gold standard treatment for distal femur fractures. Despite improvements that preserve the biological conditions for bone healing, there are concerns standard locked plating constructs may be overly stiff. Biphasic plating is a novel concept designed to provide suitable fracture motion and increased implant strength to support early full weight-bearing. This study aims to demonstrate that the Biphasic Plate can be incorporated into a pre-contoured distal femur plate while providing adequate flexibility and increased implant strength. buy BGB-283 The mechanical performance of the Biphasic Plate (BP) was investigated in comparison to a standard locking plate for the distal femur (LCP-DF). Constructs were formed by mounting the implants on a bone substitute. The construct stiffness and strength under axial loading and the magnitude of interfragmentary movement were determined using finite element analysis. The Biphasic Plate exhibited a bi-linear stiffness response; at low loads, the BP construct was 55% more compliant and at high loads 476% stiffer than the LCP-DF. The Biphasic Plate provided more consistent interfragmentary movement over a wider loading range. At partial weight-bearing loads, the Biphasic Plate produced larger interfragmentary movements (0.18 vs. 0.04 mm). However, at loads equivalent to full weight-bearing, the maximum movements were substantially smaller than the LCP-DF construct (1.5 vs. 3.5 mm). The increased flexibility at low loads was provided without sacrificing implant strength with peak stress in the Biphasic Plate 63% lower than the LCP-DF construct. The biphasic plating concept can be successfully incorporated into anatomically contoured distal femur plates while providing adequate flexibility and increasing implant strength.Cancer is the second leading cause of death in the United States, claiming more than 560,000 lives each year. Osteosarcoma (OS) is the most common primary malignant tumor of bone in children and young adults, while bone is a common site of metastasis for tumors initiating from other tissues. The heterogeneity, continual evolution, and complexity of this disease at different stages of tumor progression drives a critical need for physiologically relevant models that capture the dynamic cancer microenvironment and advance chemotherapy techniques. Monolayer cultures have been favored for cell-based research for decades due to their simplicity and scalability. However, the nature of these models makes it impossible to fully describe the biomechanical and biochemical cues present in 3-dimensional (3D) microenvironments, such as ECM stiffness, degradability, surface topography, and adhesivity. Biomaterials have emerged as valuable tools to model the behavior of various cancers by creating highly tunable 3D systems for studying neoplasm behavior, screening chemotherapeutic drugs, and developing novel treatment delivery techniques. This review highlights the recent application of biomaterials toward the development of tumor models, details methods for their tunability, and discusses the clinical and therapeutic applications of these systems.Phosphorus (P) loss from agricultural areas to waterbodies is a worldwide concern. However, the effect of soil source and transport factors, such as clay (C) content and slope (S), on the magnitude of the P transport in Brazilian subtropical soils is still understudied. The objectives of this study were i) to quantify the loss of P fractions by runoff in areas receiving pig slurry application and with variations in S and C content; ii) propose an environmental critical limit model of P (P-threshold) for Brazilian subtropical soils. Thus, two series of experiments were conducted from 2016 to 2018, one under a Nitisol with 642 g kg-1 of C and another under a Cambisol with 225 g kg-1 of C. The treatments were four P rates (0, 56, 112 and 224 kg P ha-1 year-1) superficially applied as pig slurry, on Tifton (Cynodon sp) pasture, and three S (10, 20 and 30% in the Nitisol and 15, 25 and 35% in Cambisol). P losses increased in both soils as the S and P rates rose. The Nitisol showed P losses three times higher than the Cambisol. Soil S above 25% promotes P losses at a rate three times higher than in soil below this limit. Therefore, we propose a P-threshold model for Mehlich-1 extractable P levels for Brazilian subtropical soils as "P-threshold = (42.287 + C) - (0.230 S + 0.0123 C S)" in soils with a S ≤ 25% and "P-threshold = (42.287 + C) - (-0.437 S + 0.039 C S)" in soils with a S >25%, where both C and S are shown in percentage. The soil clay content and slope are aggravating factors to the P transfer process, thus must be considered in suitable models to predict the P losses risk.
Both psoriatic arthritis (PsA) and rheumatoid arthritis (RA) have a significant impact on quality of life, but few reports have compared the two diseases. The current study assessed health-related quality of life (HRQoL) in PsA at diagnosis and after five years compared with early rheumatoid arthritis (RA) and a matched general population.

Patients with early PsA and early RA included in two Swedish registries with HRQoL data measured by the Medical Outcomes Study Short Form 36 (SF-36) at baseline and at five years follow-up were included. Differences in SF-36 scores compared with the general population were calculated for each patient. Physical function, disease activity, the delay before diagnosis, pain, and general wellbeing were used as explanatory variables. Statistical tests included t-tests and univariate and multivariate linear regression.

PsA (n=166) and RA (n=133) patients of both sexes had significantly reduced HRQoL at disease onset. After five years, PsA patients still had impairments in several domains of SF-36, whereas RA patients had an almost normalized HRQoL.
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