Photoacoustic method for measuring the elasticity of polydimethylsiloxane at various mixing ratios.

Measuring elasticity without physical contact is challenging, as current methods often require deconstruction of the test sample. This study addresses this challenge by proposing and testing a photoacoustic effect-based method for measuring the elasticity of polydimethylsiloxane (PDMS) at various mixing ratios, which may be applied on the wide range of applications such as biomedical and optical fields. A dual-light laser source of the photoacoustic (PA) system is designed, employing cross-correlation signal processing techniques. The platform systems and a mathematical model for performing PDMS elasticity measurements are constructed. During elasticity detection, photoacoustic signal features, influenced by hardness and shapes, are analyzed using cross-correlation calculations and phase difference detection. Results from phantom tests demonstrate the potential of predicting Young's modulus using the cross-correlation method, aligning with the American Society for Testing and Materials (ASTM) standard samples. However, accuracy may be affected by mixed materials and short tubes. Normalization or calibration of signals is suggested for aligning with Young's coefficient.

Clinical characteristics and reproductive outcomes in infertile men with testicular early and late maturation arrest.

OBJECTIVE: To compare the clinical characteristics and reproductive outcomes of nonobstructive azoospermic men with uniform early and late maturation arrest. METHODS: Patients with biopsy-documented uniform maturation arrest undergoing testicular sperm retrieval and complete medical records were enrolled in the present study. Their medical history, physical examination findings, testicular volume, serum hormone parameters, genetic anomalies, sperm retrieval, and reproductive outcomes were retrospectively analyzed. RESULTS: In a cohort of 223 nonobstructive azoospermic men, 34 men with uniform maturation arrest (21 early maturation arrest and 13 late maturation arrest) were identified. No significant differences were seen in the age distribution, testicular volume, or hormone parameters between patients with early and late maturation arrest. Only 13 patients (38.2%) had a normal serum follicle-stimulating hormone level and normal testicular volume. Patients with early maturation arrest had a greater frequency of overall genetic anomalies, and patients with late maturation arrest had a greater frequency of previous testicular insults. The sperm retrieval and impregnation rate were nonsignificantly greater in patients with late maturation arrest. CONCLUSION: Maturation arrest has a variety of causes and presents with diverse phenotypes. Not all patients with uniform maturation arrest have a normal follicle-stimulating hormone level or testicular volume. Patients with early maturation arrest have a greater incidence of genetic anomalies and are more likely to have worse reproductive outcomes than are patients with late maturation arrest.

Magneto-optical nonreciprocal phase shift in garnet/silicon-on-insulator waveguides.

We demonstrate the integration of a single-crystal magneto-optical film onto thin silicon-on-insulator (SOI) waveguides by use of direct wafer bonding. Simulations show that the high confinement and asymmetric structure of SOI allows an enhancement of approximately 3x over the nonreciprocal phase shift achieved in previous designs; this value is confirmed by our measurements. Our structure will allow compact magneto-optical nonreciprocal devices, such as isolators, integrated on a silicon waveguiding platform.