Utility of shear wave ultrasound elastography in evaluation of testicular stiffness in patients with varicocele

Background Testicular varicocele is the most frequent cause of male infertility. The study aimed at evaluation of testicular stiffness in patients with varicocele measured by shear wave ultrasound elastography (SWE) in correlation to patient semen analysis (total sperm count) and varicocele grade. This case–control study involved 50 patients (40 patients with bilateral testicular varicocele and 10 patients with unilateral Lt. testicular varicocele of different grades) and 25 healthy controls. All participants underwent physical examination, semen analysis (patient group subdivided in two groups: group A; normospermic and group B; oligospermic), scrotal grey scale and Doppler ultrasound, and shear wave ultrasound elastography with measurement of mean testicular stiffness. Evaluation of testicular stiffness and correlation to varicocele grade and semen analysis (total sperm count) were done. Results The mean testicular stiffness value measured by SWE in patients with testicular varicocele was greater than that of healthy controls (7.46 ± 1.64 kPa vs. 3.84 ± 0.62 kPa, P < 0.001). The mean testicular stiffness value in group B exceeded that of group A (8.57 ± 1.53 kPa vs. 6.34 ± 1.76 kPa, P = 0.001). A moderate positive correlation was found between mean testicular stiffness value and the varicocele grade (P = 0.01) which was more evident in group B than in group A (P = 0.01). Conclusions Testicular ultrasound SWE is a quantitative noninvasive imaging method which helps in the assessment of testicular parenchymal changes due to varicocele. Higher testicular stiffness values were found in testes of patients with varicocele, more in oligospermic patients than the testes of healthy controls. Testicular stiffness is moderately correlated to varicocele grade.

Stiffness Evaluation and fast matching method of mechanical composite structure

Stiffness evaluation can improve the reliability and safety of combined machinery, which is often used to evaluate the performance of combined machinery. In order to study the stiffness evaluation method and rapid matching of mechanical composite structure, the composite machinery composed of high-power diesel is taken as the research object. The results show that the error between test mode and calculation mode is no more than 10%, indicating the reliability of finite element simulation model; two characterization methods of static stiffness and dynamic stiffness are determined, and the analysis methods of two characterization methods of combined machinery are discussed one by one. Taking the combined machinery of body, main bearing cap and oil pan as the research object, the overall stiffness characterization data of three parts are obtained one by one; finally, the principles of mechanical combination Stiffness Evaluation and rapid matching are summarized. This study provides a reference for Stiffness Evaluation and rapid matching of combined mechanical structures.

Vascular stiffness evaluation in elderly patients with hypertension in conjunction with geriatric syndromes

Цель: изучить параметр жесткости артериальной стенки (сердечно-лодыжечный сосудистый индекс (СЛСИ)) у пациентов 60 лет и старше с артериальной гипертонией (АГ) во взаимосвязи с синдромом старческой астении (ССА) и другими гериатрическими синдромами.

Assessment of Geometric Nonlinearities Influence On NASA Rotor 37 Response to Blade Tip/Casing Rubbing Events

This paper uses a recently derived reduction procedure to study the contact interactions of an industrial blade undergoing large displacements. The reduction technique consists in projecting the dynamical problem onto a reduction basis composed of Craig-Bampton modes and a selection of their modal derivatives. The internal nonlinear forces due to large displacements are evaluated with the stiffness evaluation procedure and contact is numerically handled using Lagrange multipliers. The numerical strategy is applied on an open industrial compressor blade model based on the NASA rotor 37 blade in order to promote reproducibility of results. Two contact scenarios are investigated: one with direct contact between the blade and the casing and one with an abradable material deposited on the casing. The influence of geometric nonlinearities is assessed in both cases. In particular, contact interaction maps and abradable coating wear pattern maps are used to identify the main interactions that can be detrimental for the engine integrity.

Measuring The Tensile Strain of Wood By Visible And Near-Infrared Spatially Resolved Spectroscopy

Wood has various mechanical properties, so stiffness evaluation is critical for quality management. Using conventional strain gauges constantly is high cost, also challenging to measure precious wood materials due to the use of strong adhesive. This study demonstrates the correlation between light scattering changes inside the wood cell walls and tensile strain. A multifiber-based visible-near-infrared (Vis–NIR) spatially resolved spectroscopy (SRS) system was designed to rapidly and conventiently acquire such light scattering changes. For the preliminary experiment, samples with different thicknesses were measured to evaluate the influence of thickness. The differences in Vis–NIR SRS spectral data diminish with an increase in sample thickness, which suggests that the SRS method can successfully measure the whole strain (i.e., surface and inside) of wood samples. Then, for the primary experiment, 18 wood samples with the same thickness (2 mm) were tested to construct a strain calibration model. The prediction accuracy was characterized by a determination coefficient (R2) of 0.86 with a root mean squared error (RMSE) of 297.89 με for five-fold cross-validation; for test validation, The prediction accuracy was characterized by an R2 of 0.82 and an RMSE of 345.44 με.