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961.
962.
应用循环伏安法制备了nano-Pt/GC修饰电极,优化了铂微粒在电极表面的沉积条件,并用扫描电子显微镜(SEM)和在硫酸中的循环伏安曲线对其进行了表征,结果表明铂微粒较为均匀地分散在玻碳电极表面,粒径约为140nm,电极具有很大的比表面积.实验研究表明nano-Pt/GC修饰电极对甲酸电氧化的催化性能明显好于铂片电极,在该电极上甲酸正向扫描和反向扫描时的氧化峰电流分别是铂片电极上的4.37倍和3.49倍,有效地提高了金属铂的利用率,玻碳电极上铂微粒的最佳沉积条件为循环次数为100次、沉积速度为5mV/s. 相似文献
963.
Liu WM Lai SJ Lu LZ Shi FX Zhang J Liu Y Yu B Tao ZR Shen JD Li GQ Wang DQ Li JJ Tian Y 《Journal of Zhejiang University. Science. B》2011,12(9):736-743
The effects of different fatty acid (FA) contents in diet on serum parameters, FA compositions of eggs and meat, and liver morphological changes were studied in Shaoxing laying ducks. A total of 264 ducks at 17 weeks were fed a control diet or a diet containing 30 g/kg fish oil (FO), 25 g/kg sunflower oil (SO), or 30 g/kg palm oil with 20 g/kg beef tallow (PBO). Malondialdehyde (MDA) content in the liver and the serum of ducks fed the PBO diet was significantly (P<0.05) higher than that of ducks fed the other diets. Triglyceride (TG) and total cholesterol (TC) levels were significantly lower (P<0.05) in ducks fed the FO diet. Serum TC also was lower in ducks fed the SO diet. Superoxide dismutase (SOD) activity was also affected by diets. The contents of polyunsaturated FAs (PUFAs) in eggs and meat were significantly higher (P<0.001) in ducks fed the FO and SO diets than in ducks fed the control diet. The level of C22:6 (n-3) FA in ducks fed the FO diet was significantly higher than that in ducks fed the other diets. However, the conversion efficiency of the longer-chain C20:5 (n-3) FA was higher than that of C22:6 (n-3). Ducks fed the PBO diet exhibited lipid droplet accumulation in the liver. These results demonstrate that a diet enriched with different FAs has strong effects on serum lipid levels and the deposition of PUFAs into tissue lipids. 相似文献
964.
We hypothesized whether systemic administration of high-molecular-weight hyaluronic acid (HMW HA) could rescue trinitrobenzene
sulfonic acid (TNBS)-induced colitis through Toll-like receptor 4 (TLR4) signal. C3H/HeN mice and C3H/HeJ mice were used.
Mice were divided into four groups: control, 50% ethanol treatment group, TNBS treatment group, and TNBS plus HA treatment
group. The weight changes, clinical scores, macroscopic scores, and histological scores were recorded. Cyclooxygenase 2 (Cox-2)
and prostaglandin E2 (PGE2) expressions were measured both in colons and peritoneal macrophages from these mice. HA was a rescue therapy for the colitis
induced by TNBS only in C3H/HeN mice. The clinical score, macroscopic score, and histological score were much lower in C3H/HeN
mice receiving TNBS plus HA treatment. Cox-2 and PGE2 expressions only increased in C3H/HeN mice. These Cox-2 expressing cells were macrophages. HA can also promote the production
of Cox-2 and PGE2 in peritoneal macrophages from C3H/HeN mice. Our data demonstrated that HMW HA can rescue TNBS-induced colitis through inducing
Cox-2 and PGE2 expressions in a TLR4-dependent way. Macrophages may be the effector cells of HMW HA. 相似文献
965.
Liu P Shen SR Ruan H Zhou Q Ma LL He GQ 《Journal of Zhejiang University. Science. B》2011,12(11):923-930
Naturally fermented pickles harbour many lactic acid bacteria (LAB). Forty-three LAB strains with conjugated linoleic acid
(CLA)-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, lp15 identified as
Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability (26.1% conversion)
at 48 h in de Man Rogosa Sharpe (MRS) broth in the presence of 100 μg/ml of linoleic acid (LA). Compared to other strains,
L. plantarum strain lp15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 μg/ml. This strain converted
about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA (9-CLA) and trans-10, cis-12 CLA (10-CLA)], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by lp15 remained stable
between 100 to 600 μg/ml LA levels in the medium, it dropped sharply at 1000 μg/ml. Taken together, the lp15 strain displayed
relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing
the CLA content in food-sources like pickles. 相似文献
966.
采用成核/晶化隔离法制备出和锌铝水滑石(Zn/Al-LDHs),并以其为反应前体(主体),以乙二醇为分散介质,分别采用返混/沉淀法和原位法将具有荧光吸收性能的肉桂酸(客体)引入CO32-型水滑石层间,制备出肉桂酸插层水滑石,利用红外光谱仪、荧光分光光度计等手段对样品进行了表征。结果表明,肉桂酸根可以取代锌铝水滑石前体层间的CO32-离子,组装得到结构良好的肉桂酸插层水滑石,其在300~400nm之间有良好的荧光吸收峰,具有一定的荧光效果。 相似文献
967.
968.
张铁莉 《唐山师范学院学报》2011,33(2):1-3
采用非共价印迹技术,以3,4,5-三羟基苯甲酸(3,4,5-THBA)为印迹分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,乙腈为致孔剂,60℃热引发制备了印迹聚合物P(3,4,5-THBA),用高效液相色谱法和Scatchard作图评价了其选择性结合特性。结果表明,P(3,4,5-THBA)对3,4,5-THBA具有选择性结合能力,氢键结合在其分子识别过程中起主要作用,其中存在两类结合位点,高亲和力结合位点的离解常数KD1=2.4×10-4mol/L,最大结合位点数Qmax1=30.6μmol/g;低亲合力结合位点的离解常数KD2=2.3×10-3mol/L,最大结合位点数Qmax2=91.1μmol/g。 相似文献
969.
选用4个材料亲本,按4×4NCⅡ完全双列杂交设计,配制了12个组合,对小麦植酸含量的杂种优势及其遗传力进行了研究。结果表明,偃展4110X淮麦20的中亲优势和超低亲优势最大,偃展4110×CN8081的中亲优势最小,CN8081×小偃986的超低亲优势最小;淮麦20的一般配合力效应值最大,小偃986的特殊配合力效应值最小;植酸的广义遗传力为85.9%,狭义遗传力为32.3%。 相似文献
970.
以丙烯酸和环己醇为原料合成丙烯酸环己酯,考察了不同催化剂、阻聚剂用量、催化剂用量、醇酸比及反应时间对丙烯酸转化率和选择性的影响,得到的最佳工艺条件为:催化剂为甲基苯磺酸,用量为1%,醇酸比为1.5,阻聚剂为3‰,带水剂用量为5%,丙烯酸转化率大于90%,选择性大于80%. 相似文献