Ultraviolet Fe ii emission in z∼ 2 quasars Sameshima, H.; Maza, J.; Matsuoka, Y. ...
Monthly notices of the Royal Astronomical Society,
05/2009, Letnik:
395, Številka:
2
Journal Article
The properties of dissipative haptic displays allow larger workspaces that permit a whole body interaction useful for sports, rehabilitation, and large-scale object design applications. To that end ...we designed and constructed the brake actuated manipulator (BAM) with 2m 3 workspace. Dissipative devices are capable of simulating virtual objects through resistance analogous to active devices. However, the challenge remains for path guidance paradigms because neither impedance nor admittance control can be used to actively steer limb movements. Here we first define a new way to create and track a path during path guidance with a twinned vector field to allow bilateral motion. Using this new path definition three controllers, velocity ratio, force cancelling, and force mapping are compared with and without visual feedback. The results indicate that both force controllers provide better guidance over velocity control; the force mapping technique resulted in the smoothest limb trajectory. The presence of visual feedback was found to be a critical factor for path guidance using dissipative devices.
Background. In mammals, the renal medulla is in a hypertonic environment related to the renal concentrating mechanism. Renal cells accumulate osmolytes such as betaine to protect cells from the ...perturbing effect of high concentration of electrolytes. Hypertonicity‐induced cell death and the effect of betaine were investigated in Madin Darby canine kidney (MDCK) cells. Methods. Cell viability was detected by 3‐(4,5‐dimethylthiazo‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay. DNA fragmentation was determined by FACS analysis, terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling (TUNEL) staining and agarose gel electrophoresis. Activities of caspase‐1, ‐3, ‐8, and ‐9 were measured. Result. When the cells were exposed to 700 mOsm medium for 24 h, 40% of the cells were detached. TUNEL staining showed that about 20% of detached cells were apoptotic, indicating that both necrosis and apoptosis contributed to the hypertonicity‐induced cell death in MDCK cells. DNA laddering was demonstrated in hypertonic cells. Caspase‐3, ‐8, and ‐9 activities of the adherent cells exposed to 700 mOsm for 24 h increased approximately 20‐, 3‐, and 4‐fold the value of isotonic cells, respectively. However, there was no significant change in caspase‐1 activity. Addition of 1 mM betaine into the medium protected the cells against the hypertonicity‐induced cytotoxicity and apoptosis. Betaine prevented the induction of caspase‐3, ‐8, and ‐9 activities after hypertonic exposure to about 50%. Conclusions. The present study demonstrates that (i) apoptosis is involved in the hypertonicity‐induced cell death in MDCK cells; (ii) caspase‐3, ‐8, and ‐9 may contribute to the apoptosis; and (iii) betaine has protective effect on the hypertonicity‐induced apoptosis.
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