掺杂对α—Fe2O3材料气敏性能的影响

以ＦｅＳｏ４．７Ｈ２Ｏ为材料，采用共沉淀法制备氧化铁，所得主体相是γ－Ｆｅ２Ｏ３和α－Ｆｅ２Ｏ３ｘ的混合物。材料经８００－８５０℃热处理后，全部转变为α－Ｆｅ２Ｏ３相。以α－Ｆｅ２Ｏ３为主体材料制成的酒敏元件，掺入ＳｎＯ２－ＺｎＯ二元导电陶瓷粉等材料后，可使元件的灵敏度提高２０％左右，在高浓度气体下，元件对乙醇和汽油的分离效果良好，是一种抗高浓度气体冲击能力强的不掺贵金属的酒敏元件。     

氧化锌电阻片等效电路的探讨

通过对三类国产氧化锌电阻片在不同波形电压作用的小电流特性进行测试,分析其规律.提出了新的氧化锌电阻片等效电路,并对高压直流输电换流站内无间隙避雷器的设计、试验提出了建议.     

日粮中不同锰、铜水平对肉仔鸡生长和胫骨性能的影响

本实验采用二因子4×3设计。选1日龄健康星布罗(Starbro)肉用雏鸡288只进行了8周实验,所设日粮锰水平为60,150,300和600ppm,铜水平为12.6,100和250ppm。在8周末采取胫骨样品,检测其中无机元素和羟脯氨酸含量变化。结果,600ppm锰和100～250ppm铜改善了O～3周龄雏鸡的饲料效率,但对全期仔鸡的增重、采食量和饲料效率无明显作用。提高日粮中锰水平,影响了骨矿化作用和胫骨中羟脯氨酸的正常含量,引起骨质下降,这种作用受到锰、铜互作的影响。锰、铜在骨中的沉积具有极强的连锁性,其沉积量之间呈显著正相关。综上可见,过高的日粮锰(150ppm以上)、铜(100ppm以上)水平对肉仔鸡生长不利。     

饲粮添加锰对3~4月龄獭兔脂肪沉积和脂肪组织脂质代谢的影响

本试验旨在研究饲粮添加锰对生长獭兔脂肪组织脂质代谢的影响。选用初始体重相近、健康状况良好的3月龄獭兔200只,随机分为5组(每组40个重复,每个重复1只),分别饲喂在基础饲粮中添加0(对照)、5、10、20、40 mg/kg锰(以硫酸锰的形式)的试验饲粮。预试期7 d,正试期29 d。结果表明:1)与对照组相比,饲粮中添加10~20 mg/kg锰显著降低了肩胛脂肪沉积率(P<0.05),饲粮中添加5~40 mg/kg锰显著降低了胃周脂肪沉积率(P<0.05)。饲粮中锰添加水平对肾周脂肪沉积率没有显著影响(P>0.05)。2)饲粮中锰添加水平对肉碱脂酰转移酶2(CPT2)、激素敏感脂酶(HSL)和过氧化物酶体增殖物激活受体β(PPARβ)基因的表达量没有显著影响(P>0.05)。与对照组相比,饲粮中添加20~40 mg/kg锰显著降低了脂肪酸合成酶(FAS)基因的表达量(P<0.05);饲粮中添加20~40 mg/kg锰显著降低了乙酰辅酶A羧化酶(ACC)基因的表达量(P<0.05);饲粮中添加10~40 mg/kg锰显著提高了肉碱脂酰转移酶1(CPT1)基因的表达量(P<0.05);饲粮中添加10~20 mg/kg锰显著提高过氧化物酶体增殖物激活受体α(PPARα)基因的表达量(P<0.05)。综上所述,饲粮中添加锰影响了3~4月龄獭兔的脂肪沉积和脂肪组织脂质代谢,锰添加水平为20 mg/kg时,可以有效促进脂肪组织的氧化分解,抑制脂肪组织的合成,并能降低体脂肪的沉积率。     

The dynamic changes of plasma nitric oxide and endothelin-1 in prehepatic portal hypertension rats

AIM:To observe the dynamic changes of plasma levels of nitric oxide(NO) and endothelin (ET-1) in portal veins of the rats during prehepatic portal hypertension, and investigate the role of them in hyperdynamic circulation.METHODS:The models of prehepatic portal hypertension were established in Sprague-Dawley rats by means of partial portal vein ligation (PVL). The plasma levels of nitrite/nitrate (NO₂^-/NO₃^-) and ET-1 in the portal veins were detected by the method of nitric reductase and radioimmunoassay, respectively. In this study, rats were divided into normal, sham operation (SO) and PVL group. SO and PVL rats were divided into several subgroups according to different time after operations. Meanwhile, the changes of several hemodynamic indexes in these rats were also measured.RESULTS:The levels of NO₂^-/NO₃^- were significantly increased and ET-1 were significantly decreased in rats at different time after PVL compared with normal control, whereas the hemodynamic indexes changed accordingly.CONCLUSION:The portal hypertensive rats are in hyperdynamic circulatory state (HCS). NO and ET-1 may play an important role in the induction and maintenance of HCS.     

The protective effects of angiotensin Ⅱ receptor blocker irbesartan on kidney function in diabetic rats

AIM: To investigate the effects and mechanisms of irbesartan, one of the angiotensin Ⅱreceptor blockers, on kidney function in diabetic rats. METHODS: Forty adult male Wistar rats were randomly divided into four groups: control group, diabetes group, irbesartan group and captopril group. At the end of 12 weeks, the rats were sacrificed. Urine volume, body weight, kidney weight/body weight, plasma, glucose, glycosylated hemoglobin (HbA₁c), urinary β₂-microglobulin (β₂-MG) excretion, urinary albumin excretion rate (UAR), creatinine clearance (Ccr) were measured. Nitric oxide (NO) and endothelin-1 (ET-1) levels in plasma, urinary and renal tissues were determined. RESULTS: Urine volume, kidney weight/body weight, plasma glucose, HbA1C, UAR, Ccr, urinary β₂-MG excretion, NO and ET-1 levels of urinary, blood and renal tissue in diabetic rats were significantly higher than those of normal controls ( P<0.01). UAR, Ccr, urinary β₂-MG excretion, ET-1 and NO levels of urinary and renal tissue in rats of irbesartan and captopril groups were significantly lower than those of DM rats ( P<0.01). There were positive relationships among the levels of plasma, urinary, renal tissue ET-1, NO and UAR, Ccr and urinary β₂-MG excretion. CONCLUSION: Irbesartan could prevent from the injury of renal function in STZ-induced diabetic rats. And it maybe one of the most importan mechanisms that irbesartan could reduce the NO and ET-1 levels in STZ-induced diabetic rats.     

茶皂素、生石灰等防治稻田福寿螺的效果评估

福寿螺已成为我国南方局部稻区严重危害水稻的有害生物,为解决常用的化学杀螺剂污染环境和农产品的问题,分别在室内和大田环境下研究了生石灰、碳酸氢铵、茶麸和茶皂素4种替代物质防治福寿螺的效果。茶皂素、茶麸和生石灰对稻田福寿螺有很好的防治作用。在室内试验中40 mg/L和50 mg/L茶皂素处理在48 h 即达到了100%的防效;在大田试验中茶皂素6.0 g/m²的处理在第4天、1.5 g/m²的处理在第16天均达到了100%的防治效果,且速效性和持效性也显著优于其它物质。30 g/m²和45 g/m²的茶麸处理以及45 g/m²的生石灰处理在大田试验第16天的防治效果也在80%以上。这3种物质对稻田稗草还有很好的抑制作用。碳酸氢铵对福寿螺防治效果较差,且能促进稻田稗草的发生。研究结果表明,茶皂素、茶麸和生石灰可作为化学杀螺剂的替代物质在大田中推广应用。     

Effects of exogenous salicylic acid and nitric oxide on lipid peroxidation and antioxidant enzyme activities in leaves of Brassica napus L. under nickel stress

The effects of nickel in combination with salicylic acid (SA) and sodium nitroprusside (SNP), a donor of nitric oxide (NO) on 21-day-old canola plants were evaluated. Exposure to 0.5 mM NiCl₂·6H₂O for 10 days resulted in toxicity symptoms such as chlorosis and necrosis at leaves. Addition of 0.2 mM SA or 0.2 mM SNP slightly reduced the toxic effects of nickel. After application of both SA and NO, these symptoms considerably decreased. Treatment with Ni resulted in a decrease in dry weight of roots and shoots and chlorophyll content of leaves. In Ni-treated plants, level of lipoxygenase activity and malondialdehyde (MDA), H₂O₂ and proline contents significantly increased, while the activities of the antioxidant enzymes such as catalase, guaiacol peroxidase and ascorbate peroxidase decreased in leaves. The results indicated that Ni caused an oxidative stress in canola plants. The Ni-stressed plants exposed to SA or NO, especially to SA + NO, exhibited an improved growth as compared to Ni-treated plants. SA or NO, especially both together considerably reduced root-to-shoot translocation of Ni and increased the activities of the antioxidant enzymes in leaves of Ni-stressed plants. Interaction of SA and NO improved the chlorophyll content and decreased the level of lipid peroxidation, H₂O₂ and proline accumulation in leaves. These results suggest that SA or NO in particular their combination counteract the negative effects of Ni on canola plants.