Visualization of oscillating flow in a double-inlet pulse tube refrigerator with a diaphragm inserted in a bypass-tube

The double-inlet pulse tube refrigerator that has a diaphragm inserted in a bypass-tube, which enabled it to transmit a pressure oscillation whereas to obstruct a DC gas flow, was manufactured and tested. The oscillating flow behavior inside of the refrigerator was studied by using a smoke-wire flow visualization technique. It was found that if the diaphragm was optimized, the performance would be improved more than that of the refrigerator with a bypass valve due to the increase in the PV work of the gas and the decrease in the convective heat loss caused by a secondary flow

Paeoniflorin ameliorates acquisition impairment of a simple operant discrimination performance caused by unilateral nucleus basalis magnocellularis lesion in rats

The effect of paeoniflorin on learning impairment of operant brightness discrimination performance　was investigated in rats with unilateral nucleus basalis magnocellularis（NBM）lesion. The animals　with unilateral NBM lesion exhibited a significant acquisition impairment of brightness discrimination task during the early phase of a training period（1-5days after starting the training session). When　administered daily during a training period，paeoniflorin significantly improved the learning impairment　of unilateral NBM-lesioned rats at 0.01 but not 0.1mg／kg／day（p.o.）. Tacrine （0.3mg／kg／day，p.o.）， a　cholinesterase inhibitor，also significantly ameliorated the learning deficit. These results suggest that　paeoniflorin improves the impairment of non-spatial learning performance caused by cholinergic　dysfunction in rats and that it may have a beneficial effect on senile dementia

Potential lethal damage repair in glioblastoma cells irradiated with ion beams of various types and levels of linear energy transfer

Glioblastoma (GBM), a Grade IV brain tumour, is a well-known radioresistant cancer. To investigate one of the causes of radioresistance, we studied the capacity for potential lethal damage repair (PLDR) of three altered strains of GBM: T98G, U87 and LN18, irradiated with various ions and various levels of linear energy transfer (LET). The GBM cells were exposed to 12C and 28Si ion beams with LETs of 55, 100 and 200 keV/μm, and with X-ray beams of 1.7 keV/μm. Mono-energetic 12C ions and 28Si ions were generated by the Heavy Ion Medical Accelerator at the National Institute of Radiological Science, Chiba, Japan. Clonogenic assays were used to determine cell inactivation. The ability of the cells to repair potential lethal damage was demonstrated by allowing one identical set of irradiated cells to repair for 24 h before subplating. The results show there is definite PLDR with X-rays, some evidence of PLDR at 55 keV/μm, and minimal PLDR at 100 keV/μm. There is no observable PLDR at 200 keV/μm. This is the first study, to the authors’ knowledge, demonstrating the capability of GBM cells to repair potential lethal damage following charged ion irradiations. It is concluded that a GBM’s PLDR is dependent on LET, dose and GBM strain; and the more radioresistant the cell strain, the greater the PLDR