不同老化条件对轮胎耐久性能及损坏形式的影响

研究氮氧老化、热氧老化和臭氧老化3种老化条件对轮胎耐久性能及损坏形式的影响。结果表明:热氧老化后轮胎耐久性能明显下降,氮氧老化后轮胎耐久性能略有下降,臭氧老化后轮胎耐久性能变化不大;氮氧老化和热氧老化后轮胎耐久损坏形式均为胎侧鼓包脱层,其中热氧老化后轮胎损坏更严重,而臭氧老化后轮胎耐久损坏形式为胎肩出现裂口;氮氧老化和热氧老化后剖析胎面胶的硬度和定伸应力增大,拉断伸长率减小,生热变化不大;臭氧老化对剖析胎面胶性能的影响不大。

Regulation of Nitric Oxide on the Aging Process of Wheat Leaves

When the first fully expanded leaf of wheat ( Triticum aestivum L.) seedlings with two leaves were treated with different concentrations (0.05, 0.10, 0.20 and 0.50 mmol/L) of nitric oxide donor, sodium nitroprusside (SNP), the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) were reduced by the lower concentrations (0.05, 0.10 and 0.20 mmol/L), but enhanced by the higher concentration of SNP (0.50 mmol/L). The protective effect of 0.10 mmol/L SNP was the most obvious. Furthermore, the treatment with 0.10 mmol/L SNP on the above seedlings until the fourth leaves were fully expanded attenuated the accumulation of H2O2, superoxide anion radical (O-2(-)) and MDA, also counteracted the degradation of chlorophyll and soluble proteins, especally Rubisco, both leading to the effective delay of aging process in wheat leaves. The effects of different SNP concentrations (0.05, 0.10, 0.20, 0.50, 1.00 and 5.00 mmol/L) also displayed a dual role in an aging experiment of chloroplasts in vitro, one of which, 0.2 mmol/L SNP treatment, protected the membrane structure and attenuated the degradation of Rubisco effectively. Based on the present results, it was inferred that lower concentrations of nitric oxide (NO) might play a role in delaying aging process in wheat leaves, i.e., might attribute to decrease the level of reactive oxygen species (ROS) and the alleviation of further oxidative damage caused by ROS.

耐裂口高气密性全钢子午线轮胎气密层胶配方的开发

介绍耐裂口高气密性全钢子午线轮胎气密层胶配方的开发。试验结果表明:通过添加无机填料Suprex,减小炭黑N660和环保油用量,并调整硫化体系,胶料的门尼焦烧时间和硫化时间延长,硫化胶的物理性能、气密性、耐屈挠和耐裂口性能提高;成品轮胎的耐久性能、气密性和耐氮氧老化性能提高。

Effect of lipopolysaccharide on diarrhea and gastrointestinal transit in mice: Roles of nitric oxide and prostaglandin E_2

AIM: To investigate the effect of lipopolysaccharide (LPS)on the diarrheogenic activity, gastrointestinal transit (GIT),and intestinal fluid content and the possible role of nitric oxide (NO) and prostaglandin E2 (PGE2) in gastrointestinal functions of endotoxin-treated mice.METHODS: Diarrheogic activity, GIT, and intestinal fluid content as well as nitric oxide and PGE2 products were measured after intraperitoneal administration of LPS in mice.RESULTS: LPS dose-dependently accumulated abundant fluid into the small intestine, induced diarrhea, but decreased the GIT. Both nitric oxide and PGE2 were found to increase in LPS-treated mice. Western blot analysis indicated that LPS significantly induced the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 in mice intestines. Pretreatment with NG-nitro-L-arginine-methyl ester (L-NAME, a non-selective NOS inhibitor) or indomethacin (an inhibitor of prostaglandin synthesis) significantly attenuated the effects of LPS on the diarrheogenic activity and intestine content, but reversed the GIT.CONCLUSION: The present study suggests that the pathogenesis of LPS treatment may mediate the stimulatory effect of LPS on nitric oxide and PGE2 production and NO/prostaglandin pathway may play an important role on gastrointestinal function.

Effects of Warm Needling at Zusanli(ST 36)on NO and IL-2 Levels in the Middle-Aged and Old People

42 middle-aged and old people at the age between 55-70 years were selected and given the warm needling at Zusanli (ST 36), and their IL-2 and NO contents of peripheral blood before and after acupuncture were determined. The results showed that IL-2 and NO contents increased significantly after the warm needling (P<0.01).

Actions of NO and INOS on Endotoxin Induced rat Acute Lung Injury and Effect of Rhubarb on Them

This study is to explore the actions of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) on endotoxin (lipopolysaccharide, LPS) induced rat acute lung injury (ALI) and effect of Rhubarb on them. LPS was injected into the sublingual vein of male Wistar rats to prepare ALI animal models. The rats were divided into 4 groups: LPS, control, Rhubarb, and dexamethasone. Macroscopic and histopathological examinations of the lung specimens were performed and the biological indexes of lung, including wet weight/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary vascular permeability and pulmonary alveolar permeability were observed. In the mean time, the contents of serum NO and the activities of lung tissue homogenate iNOS were measured. The results showed that in the LPS group, the injury and celluar infiltration in the pulmonary stroma and alveoli were more prominent than that in the control group. Lung wet weight/dry weight, the rate of neutrophils, protein content, pulmonary alveolar permeability, pulmonary vascular permeability were significantly increased (P<0.01); NO and iNOS were also markedly elevated (P<0.01). In the groups of dexamethasone and Rhubarb, the histopathological changes were significantly milder, and all the above biological indexes of lung injury and the contents of NO and the activities of iNOS were correspondingly decreased (P<0.05). The above data demonstrate that NO and the activities of iNOS play an important role in the onset of ALI; dexamethasone and Rhubarb interfering treatment can ameliorate lung injury and decrease the concentrations of NO and iNOS, showing that through inhibiting the levels of NO and the activities of iNOS, these 2 agents exert protective effect on ALI induced LPS.

Effect of Acupuncture on NO, NOS and Ca^(2+)-Mg^(2+)-ATPase Activity in Brain Tissue of Subacute Aging Rats Induced by D-galactose

Objective： To explore the mechanism of acupuncture in treating brain aging. Methods： Forty healthy Wistar rats were randomly divided into 4 groups with 10 rats in each group. The rats in the control group didn＇t received modeling and treatment. The rats in the model group, the Governor Vessel acupoints group （GVA group） and the body acupoints group （BA group） were induced as subacute aging rat model. The rats in the model group didn＇t take treatment. On the modeling day, the rats in the GVA group received acupuncture at Baihui （GV 20） and Dazhui （GV 14） while the rats in the BA group received acupuncture at Guanyuan （CV 3） and Zusanli （ST 36）. The contents of NO and NOS, as well as the activity of Ca^2＋-Mg^2＋-ATPase in the brain tissue of rats in each group were observed. Results： After modeling, the contents of NO and NOS of brain tissue increased significantly and the activity of Ca2^＋-Mg^2＋-ATPase decreased markedly. Acupuncture treatment could inhibit the increases of NO and NOS contents, improve the decrease of the activity of Ca^2＋-Mg^2＋-ATPase. The results of the GVA group were better than those of BA group （both P〈0.05）. Conclusion： Acupuncture improved the activity of Ca^2＋-Mg^2＋-ATPase and stabilized the NOS concentration. As a result, the NO content was balanced and the ohvsiological function of NO was fully induced for anti-a^in~, esoeciallv in the GVA group.