Measurement of abdominal muscle thickness using ultrasound: A reliability study on patients with chronic nonspecific low back pain

Background and purpose: The purpose of this study was to assess the Within-day and Between-days reliability of abdominal muscles size measurement in patients with chronic non-specific low back pain (LBP) using ultrasound (US). Materials and methods: In this study, 15 patients with chronic non-specific LBP (20-50 years old) were recruited. The reliability of the abdominal muscle size (External and Internal oblique, and Transversus abdominis) was assessed in a relaxed and contraction state by a real time US. Two images were taken on the same day with an hour interval to assess the within day reliability and the third image was taken a week later to determine the between- days reliability. Results: Within-day and between-days reliability of abdominal muscles thickness measurements using US in patients with nonspecific chronic LBP in both rest and contraction state found to be high, ICC = 0.90 for within and ICC=0.85 for between-days of Transversus abdominis muscle in rest state and ICC= 0.82 and 0.86 in contraction state, respectively. For Internal oblique muscle, ICC=0.90 (82) and ICC=0.88 (88) were found for within-day and between-days in rest and contraction state, respectively. Within-day and between-days reliability at rest of ICC=0.86 (79) and in contraction state of ICC=0.79 (75) were demonstrated for External Oblique muscle. Conclusion: Results of the present study suggest US as a reliable method to evaluate the thickness of the abdominal muscles which could be used as a reliable tool in the assessment of patients and also in evaluating the effect of different therapeutic interventions. © 2015, Mazandaran University of Medical Sciences. All rights reserved

Increasing the elevated-temperature strength of a beta titanium alloy through thermomechanically-induced phase tranformation

The effects of temperature and thermomechanical loading on the elevated-temperature tensile strength, deformation behavior, and phase transformation were studied for a low-cost metastable beta titanium alloy: Ti-13Cr-1Fe-3Al (wt.%). In-situ and ex-situ tensile tests were performed at temperatures between 25 °C to 500 °C. TEM was performed to investigate the phase transformation behavior, and the strength and Vickers hardness were compared at different loading conditions. The beta phase transformed to the omega phase under a combination of load and time at temperature. The temperature range of the phase transformation was investigated by dynamic mechanical analysis and compared with data from differential scanning calorimetry and electrical resistivity techniques. Slip trace analysis indicated that dislocation slip is the primary deformation mechanism. Both temperature and thermomechanical loading have a significant influence on deformation mode, phase transformation, and tensile strength, which can be increased by over fifty percent at elevated temperatures

Optimal Mixed Tracking/Impedance Control With Application to Transfemoral Prostheses With Energy Regeneration

We design an optimal passivitybased tracking/impedance control system for a robotic manipulator with energy regenerative electronics, where the manipulator has both actively and semi-actively controlled joints. The semi-active joints are driven by a regenerative actuator that includes an energy-storing element. Method: External forces can have a large influence on energy regeneration characteristics. Impedance control is used to impose a desired relationship between external forces and deviation from reference trajectories. Multi-objective optimization (MOO) is used to obtain optimal impedance parameters and control gains to compromise between the two conflicting objectives of trajectory tracking and energy regeneration. We solve the MOO problem under two different scenarios: 1) constant impedance; and 2) timevarying impedance. Results: The methods are applied to a transfemoral prosthesis simulation with a semi-active knee joint. Normalized hypervolume and relative coverage are used to compare Pareto fronts, and these two metrics show that time-varying impedance provides better performance than constant impedance. The solution with time-varying impedance with minimum tracking error (0.0008 rad) fails to regenerate energy (loses 9.53 J), while a solution with degradation in tracking (0.0452 rad) regenerates energy (gains 270.3 J). A tradeoff solution results in fair tracking (0.0178 rad) and fair energy regeneration (131.2 J). Conclusion: Our experimental results support the possibility of net energy regeneration at the semi-active knee joint with human-like tracking performance. Significance: The results indicate that advanced control and optimization of ultracapacitor-based systems can significantly reduce power requirements in transfemoral prostheses

Experimental estimates of the photon background in a potential light-by-light scattering study

High power short pulse lasers provide a promising route to study the strong field effects of the quantum vacuum, for example by direct photon–photon scattering in the all-optical regime. Theoretical predictions based on realistic laser parameters achievable today or in the near future predict scattering of a few photons with colliding Petawatt laser pulses, requiring single photon sensitive detection schemes and very good spatio-temporal filtering and background suppression. In this article, we present experimental investigations of this photon background by employing only a single high power laser pulse tightly focused in residual gas of a vacuum chamber. The focal region was imaged onto a single-photon sensitive, time gated camera. As no detectable quantum vacuum signature was expected in our case, the setup allowed for characterization and first mitigation of background contributions. For the setup employed, scattering off surfaces of imperfect optics dominated below residual gas pressures of 1 × 10−4 mbar. Extrapolation of the findings to intensities relevant for photon–photon scattering studies is discussed

Salivary Gland Tumors in Maxillofacial Region: A Retrospective Study of 130 Cases in a Southern Iranian Population

Tumors of the salivary glands are uncommon head and neck neoplasia. We conducted a retrospective study of 392 cases over the last 6 years in Shiraz, south of Iran, to investigate the clinicopathological features of these tumors in Iranian population. The age of the patients ranged from 8 to 85 years, with the mean age 44.57 ± 14.65 years and male-to-female (M : F) ratio was 1.02 : 1. For benign tumors, there was a propensity towards females, whereas the malignant tumor was more common in males. The ratio of benign tumors to malignancies was 2.19 : 1. Pleomorphic adenoma (PA) was the most common tumor and accounted for 85% of all benign tumors, followed by Warthin's tumor (8.6%). Of the 125 malignancies, adenoid cystic carcinoma (40%), mucoepidermoid carcinoma (24%) and invasive squamous cell carcinoma (16%) were the most common histological types. Most of the salivary gland tumors (75%) originated from major salivary glands and the remained (25%) originated from minor glands. The parotid gland was the most common site both in benign and malignant tumors. Most of our findings were similar to those in the literature, with some variations. The salivary tumors slightly predominated in males. Adenoid cystic carcinoma and mucoepidermoid carcinoma constituted the most common malignancies

Cerebrospinal fluid biomarkers as a measure of disease activity and treatment efficacy in relapsing-remitting multiple sclerosis

Cerebrospinal fluid (CSF) biomarkers can reflect different aspects of the pathophysiology of relapsing-remitting multiple sclerosis (RRMS). Understanding the impact of different disease modifying therapies on the CSF biomarker profile may increase their implementation in clinical practice and their appropriateness for monitoring treatment efficacy. This study investigated the influence of first-line (interferon beta) and second-line (natalizumab) therapies on seven CSF biomarkers in RRMS and their correlation with clinical and radiological outcomes. We included 59 RRMS patients and 39 healthy controls. The concentrations of C-X-C motif chemokine 13 (CXCL13), C-C motif chemokine ligand 2 (CCL2), chitinase-3-like protein 1 (CHI3L1), glial fibrillary acidic protein, neurofilament light protein (NFL), and neurogranin were determined by ELISA, and chitotriosidase (CHIT1) was analyzed by spectrofluorometry. RRMS patients had higher levels of NFL, CXCL13, CHI3L1, and CHIT1 than controls (p < 0.001). Subgroup analysis revealed higher NFL, CXCL13 and CHIT1 levels in patients treated with first-line therapy compared to second-line therapy (p = 0.008, p = 0.001 and p = 0.026, respectively). NFL and CHIT1 levels correlated with relapse status, and NFL and CXCL13 levels correlated with the formation of new magnetic resonance imaging lesions. Furthermore, we found an association between inflammatory and degenerative biomarkers. The results indicate that CSF levels of NFL, CXCL13, CHI3L1, and CHIT1 correlate with the clinical and/or radiological disease activity, providing additional dimensions in the assessment of treatment efficacy

Identification of MS-specific serum miRNAs in an international multicenter study.

ObjectiveTo identify circulating microRNAs (miRNAs) linked to disease, disease stage, and disability in MS across cohorts.MethodsSamples were obtained from the Comprehensive Longitudinal Investigation of Multiple Sclerosis (CLIMB, Boston, MA), EPIC (San Francisco, CA), AMIR (Beirut, Lebanon) as part of the SUMMIT consortium, and Stockholm Prospective Assessment of Multiple Sclerosis (Stockholm, Sweden) cohorts. Serum miRNA expression was measured using locked nucleic acid-based quantitative PCR. Four groups were compared: (1) MS vs healthy control (HC), (2) relapsing-remitting (RR) vs HC, (3) secondary progressive (SP) vs HC, and (4) RR vs SP. A Wilcoxon rank-sum test was used for the comparisons. The association between each miRNA and the Expanded Disability Status Scale (EDSS) score was assessed using the Spearman correlation coefficient. For each comparison, the p values were corrected for multiple comparisons using the approach of Benjamini and Hochberg to control the false discovery rate.ResultsIn the CLIMB cohort, 5 miRNAs (hsa-miR-484, hsa-miR-140-5p, hsa-miR-320a, hsa-miR-486-5p, and hsa-miR-320c) showed a significant difference between patients with MS and healthy individuals; among these, miR-484 remained significant after accounting for multiple comparisons (p = 0.01). When comparing RRMS with HCs, hsa-miR-484 showed a significant difference (p = 0.004) between the groups after accounting for multiple group comparisons. When SP and HC were compared, 6 miRNAs (hsa-miR-484, hsa-miR-140-5p, hsa-miR-142-5p, hsa-miR-320a, hsa-miR-320b, and hsa-miR-320c) remained significantly different after accounting for multiple comparisons. Disability correlation analysis with miRNA provided 4 miRNAs (hsa-miR-320a, hsa-miR-337-3p, hsa-miR-199a-5p, and hsa-miR-142-5p) that correlated with the EDSS during the internal reproducibility phase. Among these, hsa-miR-337-3p was the most statistically significant miRNA that negatively correlated with the EDSS in three of the MS cohorts tested.ConclusionsThese findings further confirm the use of circulating serum miRNAs as biomarkers to diagnose and monitor disease status in MS.Classification of evidenceThis study provides Class III evidence that levels of circulating miRNAs identify patients with MS