Infrared Emission from Intracluster Dust Grains and Constraints on Dust Properties

For 117 clusters of galaxies, we explore the detectability of intracluster dust grains by current and future infrared facilities, taking into account both collisional heating and sputtering of grains by ambient plasma. If the dust grains are injected into the intergalactic space with the amount and size comparable to the Galactic values, the dust-to-gas ratio is typically $10^{-6}$ and the mean dust temperature is $\sim 30$ K near the cluster center. The predicted infrared intensities lie marginally above the detection thresholds for Spitzer Space Telescope, ASTRO-F, Herschel and SPICA missions. For some nearby clusters such as Perseus, A3571, A2319, A3112 and A2204, good detections of intracluster dust signal are expected in the 70 $\mu$m band. Given rather tight constraints on the dust temperature from observed electron density and temperature, the dust mass can be inferred directly from the infrared observations. Further constraints on the size distribution will be obtained once multi-band data are available. They will definitely provide a powerful probe of the dust injection processes and dust-gas interactions in the intergalactic space.Comment: 9 pages, 10 figures. Accepted for publication in PAS

RELATIONSHIP BETWEEN THE VELOCITY OF THE CENTER OF MASS AND THE MECHANICAL WORK DONE BY THE SHOULDER AND HIP JOINTS IN PERFORMING THE BASKET TO HANDSTAND ON PARALLEL BARS

The purpose of this research was to investigate the relationship between the velocity of the center of mass and the mechanical work done by the shoulder and hip joints in performing the basket to handstand on parallel bars. Twenty-six male elite gymnasts were videotaped at the national championships. Two-dimensional motion analysis technique and inverse dynamics approach were used for calculating the kinematic and kinetic parameters. The negative work done by the shoulder joint significantly related to the velocity of the center of mass at 270 deg. point(r=0.55,

CHARACTERISTICS OF JOINT TORQUES IN PERFORMING THE BASKET TO HANDSTAND ON PARALLEL BARS

The purpose of this study was to investigate characteristics of joint torques in performing the basket to handstand on parallel bars. Twenty-six male elite gymnasts were videotaped in the national championships. Two-dimensional motion analysis technique and inverse dynamics approach were used for calculating the kinematic and kinetic parameters. The shoulder and hip joint torques did not relate to the upward velocity, but significantly related to the downward and forward velocities in performing the basket to handstand. Development of the shoulder flexion torque should be as small as possible for the execution to use the greater swing velocity

COMPARISON OF THE KIP MANEUVER AT THE HORIZONTAL BAR BETWEEN THE SKILLED AND UNSKILLED SUBJECTS

The purpose of this study was to investigate differences in the joint kinetics of the kip maneuver of the horizontal bar between ten skilled and three unskilled subjects. The kip maneuvers were videotaped with a VTR camera to obtain biomechanical data by a motion analysis technique. Kinematic characteristics of the skilled subjects were the straight body position and longer distance between the CG and the bar during the forward swing. The shoulder joint torque power of the skilled subjects under the bar was larger than that of the unskilled ones. The peak of the hip flexion power of the skilled subjects was later than that of the unskilled ones. The results suggested that the timing of motion is essential in the kip maneuver, and that the unskilled subjects should emphasize the hip flexion in later timing after the reversal point

Virtual endobronchial ultrasound for transbronchial needle aspiration

ObjectiveEndobronchial ultrasound-guided transbronchial needle aspiration could be performed better with computer-based preparation.MethodsThree-dimensional virtual bronchoscopy was used to develop 2 modes of computer-based “virtual endobronchial ultrasound.” “Virtual endobronchial ultrasound standard” used conventional virtual bronchoscopy to determine the spot and angle for transbronchial needle aspiration, which was further evaluated by virtual bronchoscopy. “Virtual endobronchial ultrasound advanced” used multiple layers of 3-dimensional images of the target lesions and associated vascular structures in combination with virtual bronchoscopy. Target lesions and associated vascular structures (eg, pulmonary artery) were visualized through half-transparent bronchial walls.ResultsBoth methods required 5 to 15 minutes of preparation per case. Virtual endobronchial ultrasound standard required only basic computer software for virtual bronchoscopy, whereas virtual endobronchial ultrasound advanced required an advanced computer application. Virtual endobronchial ultrasound advanced allowed for a more intuitive recognition of the target. Both methods were useful in evaluating the feasibility of transbronchial needle aspiration, especially when the target was out of regular mediastinal lymph nodes, or in targeting a lesion located at a high upper angle (eg, 4L lymph node). Because the puncture spot was predetermined, bronchoscopists did not have to search for the target using ultrasound at the time of actual endobronchial ultrasound-guided transbronchial needle aspiration; rather, ultrasound was used only for confirmation of the target location and visualization of transbronchial needle aspiration.ConclusionsBoth computer-based preparation methods of virtual endobronchial ultrasound were useful in predetermining the puncture spot of transbronchial needle aspiration, suggesting their potential complementary role to the conventional technique of endobronchial ultrasound-guided transbronchial needle aspiration