Introduction: A reduced specific absorption rate (SAR) version of pseudo-continuous arterial spin labeling (pCASL) pulse sequence (1,2) is designed and implemented. Using a simulation study, a set of pCASL pulse sequence parameters is found that allows reducing the flip angle of pCASL radio frequency (RF) pulses (and consequently SAR) without losing the inversion efficiency. The proposed set of...

We have studied an X-ray switch based on a gold coated indium antimonide crystal using time-resolved X-ray diffraction and demonstrated that the switch could reduce the pulse duration of a 100 ps X-ray pulse down to 20 ps with a peak reflectivity of 8%. We have used a dynamical diffraction code to predict the performance of the switch, which was then confirmed experimentally. The experiment was...

This study explores the use of scanning acoustic microscopy (SAM) as a potential tool for characterisation of arterial stiffness using aortic biopsies. SAM data is presented for human tissue collected during aortic bypass graft surgery for multi-vessel coronary artery disease. Acoustic wave speed as determined by SAM was compared to clinical data for the patients namely, pulse wave velocity (PW...

Small vibrations are simultaneously measured at two adjacent points on the aortic wall near the aortic valve by electronically alternating the directions of the ultrasonic beam. The transit delay time of the pulse wave between these two points is determined from two vibration signals obtained by this alternation beam method. The local pulse wave velocity at several millimeters on the aorta is p...

The pulse broadening and decay of coherent sound waves propagating in disordered granular media are investigated. We find that the pulse width of these compressional waves is broadened when the disorder is increased by mixing the beads made of different materials. To identify the responsible mechanism for the pulse broadening, we also perform the acoustic attenuation measurement by spectral ana...

The feasibility of the Finite Difference Time Domain (FDTD) technique for acoustic wave created an opportunity for underground cavity detection that poses strong potential for acoustic wave spectrum application. The numerous significant advances have been attained to date, and more technological challenge awaits the optimization of an acoustic system to fill the gap between expectations and pra...

Female evaluation of male signals in the context of sexual selection is often made on the basis of signal energy. Particularly in acoustic species, females may prefer male song that is broadcast at greater amplitude or power. However, song amplitude may be represented by various parameters, and the specific one(s) that are evaluated are not clear. We addressed this problem in an acoustic moth, ...

The time course of acoustic events is a critical element for the recognition of biologically meaningful sounds. Echolocating bats analyze the time intervals between their emitted biosonar pulses and the echoes returning from objects to assess target distance (range). In this study, we have explored the auditory cortex of the mustached bat, Pteronotus parnellii rubiginosus, using pairs of acoust...

Knee meniscus is a hydrated tissue; it is a fibrocartilage of the knee joint composed primarily of water. We present results of interferometric surface monitoring by which we measure physical properties of human knee meniscal cartilage. The physical response of biological tissue to a short laser pulse is primarily thermomechanical. When the pulse is shorter than characteristic times (thermal di...