A ray tracing model was established to calculate the transmission trajectory of laser beams in multipass cell (MPC). Types of MPCs with dense spot patterns were developed, and related sensor performance studies were conducted. A near-infrared light-induced thermoelastic spectroscopy (LITES)-based methane sensor based on a Raman fiber amplifier and a four-concentric-circle pattern MPC was built, and achieved excellent detection performance. This study is expected to bring new applications in environmental monitoring and fire warning.

The study focuses on establishing normative values for left ventricular (LV) and left atrial (LA) size and function using three-dimensional echocardiography (3DE) among healthy Han Chinese adults. This prospective, multicenter research was conducted across various age groups and aimed to account for ethnic variations not covered by existing American Society of Echocardiography (ASE) and European Association of Cardiovascular Imaging (EACVI) guidelines. The investigation revealed significant differences in cardiac measurements when compared to global standards, underscoring the need for population-specific norms.