Impedance matching system using triple liquid stub tuners for high-power ion cyclotron resonance heating in EAST tokamak.

Ion cyclotron resonance heating (ICRH), one of the main auxiliary methods, for high-power and long-pulse plasma heating had been developed in Experimental Advanced Superconducting Tokamak (EAST). An impedance matching system, one important part of ICRH, had been developed for high-power injection and transmitter protection by reducing the reflected power from the antenna. The input impedance in the outlet of the stub tuner can be measured by voltage-current probes installed on the coaxial transmission line between the antenna and triple liquid stub tuners, and the optimum liquid levels in the stub tuners can be calculated based on the input impedance. The calculation and adjustment process of the optimum liquid levels are described comprehensively in this article. Finally, impedance matching had been achieved between two shots during EAST experiments. In the near future, a real-time impedance matching system will be developed to prevent large variations of the ICRH antenna impedance and achieve steady-state and long-pulse operation with the ICRH system.

The effect of acetylcholine on pain-related electric activities in the hippocampal CA3 of rats.

Acetylcholine (ACh) regulates pain perception in the central nervous system. However, the mechanism of action of ACh on pain-related neurons in the hippocampal CA3 is not clear. The present study aimed to determine the effect of ACh, muscarinic ACh receptors (mAChRs) agonist pilocarpine and mAChRs antagonist atropine on the pain-evoked responses of pain-excited neuron (PEN) and pain-inhibited neuron (PIN) in the hippocampal CA3 of normal rats. The trains of electric impulses applied to the sciatic nerve were used as noxious stimulation. The electric activities of PEN or PIN in the hippocampal CA3 were recorded by using a glass microelectrode. Our results showed that, in the hippocampal CA3, the intra-CA3 microinjection of ACh (2 µg/1 µl) or pilocarpine (2 µg/1 µl) decreased the discharge frequency and prolonged firing latency of PEN, and increased the discharge frequency and shortened firing inhibitory duration (ID) of PIN, i.e. exhibiting the analgesic effect of ACh or pilocarpine. The intra-CA3 administration of atropine (0.5 µg/1 µl) produced an opposite effect. On the basis of the above-mentioned findings, we can deduce that ACh and mAChRs in the hippocampal CA3 are involved in the modulation of nociceptive response by regulating the electric activities of PEN and PIN.

[Effect of peritonitis pathomorphology on rabbit model in peritoneal dialysis].

The study about peritonitis rabbit model is rarely, although peritonitis have been considered mainly complication in peritoneal dialysis. Twelve New Zealand rabbit were divided into peritonitis group and control group. The peritonitis group rabbit were injected with the dialysate containing alive staphylococcus aureus and the control ones with 0.9% saline into the peritoneum. The pathomorphology changes of the peritonitis were observed. The results showed (1) There was proliferation and swollen of mesothelial cells, vessel dilation and infiltration of inflammation cells in the peritoneum in the peritonitis group; and no such changes in the control group. (2) The D/D0 glucose concentration in the dialysate of peritonitis group was lower than that of the control ones at any point except the 0 min (P < 0.01). (3) The ratio of Cr concentration in the dialysate to Cr concentration in the plasma in the peritnitis group was significantly higher than that of the control group (P < 0.05). (4) The WBC count in the dialysate of peritonitis group was obviously higher than that of the control group all points except 0. These results implied that after injection of alive staphylococcus aureus to the peritoneal cavity of New Zealand rabbit for 48 hours, the pathomorphology change was similar with the characteristics of peritonitis complicated with peritoneal dialysis in patient.

Effects of endotoxin on expression of ras, p53 and bcl-2 oncoprotein in hepatocarcinogenesis induced by thioacetamide in rats.

AIM: To evaluate the relationship between expression of ras, p53 and bcl-2 gene products and hepatocarcinogenesis since the endotoxemia produced from lipopolysaccharide administration and/or the hypophagocytic state of splenectomy significantly accelerated hepatocarcinogenesis induced by thioacetamide. METHODS: The hepatocarcinoma model was induced by 6-mo oral intake of 0.03% thioacetamide. During the hepatocarcinoma modeling process, rats were additionally treated with splenectomy and/or lipopolysaccharide administration. The techniques of flow cytometry, immunohistochemistry and immunoelectronmicroscopy were applied for quantitative analysis of the expression of oncogene proteins. RESULTS: In this model system, overexpression of ras p21 protein mainly occurred in the precancerous cell population or in cells in the early stage of hepatocyte transformation. The levels of ras p21 declined when nuclear DNA aneuploidy increased. Expression of bcl-2 protein slowly and steadily rose, with more hepatocytes staying in S + G2M phases, as the hepatocarcinoma became more malignant. p53 was moderately expressed during hepatocarcinogenesis. There was no statistical correlation between endotoxemia levels and the changes in levels of ras, p53 and bcl-2 gene products. CONCLUSION: Overexpression of oncogene ras p21 was considered likely to be a precursor of premalignant hepatocytes and possibly as responsible for the initiation of hepatocarcinogenesis. Bcl-2 protein expression is proportional to the severity of malignancy in hepatocarcinogenesis. p53 may be involved in a key pathway underlying the transformation and development processes of hepatocarcinoma. This study confirmed the hypothesis that there are multiple genes and multiple steps involved in hepatocarcinogenesis. Expression of oncogene proteins reflects the properties of the premalignant and malignant cells, but is not directly related to endotoxemia statistically.