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531.
董俊萍  徐引娟  龙英才 《化学学报》2007,65(21):2494-2498
采用晶种涂层的方法在单晶硅表面上制备了不同取向的MEL分子筛膜, 详细研究了膜的择优生长条件及其取向控制. 水含量和反应时间对膜的取向有较大影响. 在水含量较低的反应体系中, 缩短反应时间有利于得到(101)取向的分子筛膜. 水含量提高导致膜的取向发生变化, 由(101)取向变为(101)/(200)混合取向. 晶种层对膜的取向没有直接影响, 晶种层连续生长形成单层分子筛膜.  相似文献   
532.
Chenopodium quinoa Willd. is recognized to be an excellent nutrient with high nutritional content. However, few genotypes of quinoa were analyzed, so we found a knowledge gap in the comparison of quinoa seeds of different genotypes. This study aims to compare the physicochemical, antioxidant, and anticancer properties of seed oil from three C. quinoa genotypes. Seeds of three genotypes (white, red, and black) were extracted with hexane and compared in this study. The oil yields of these quinoa seeds were 5.68–6.19% which contained predominantly polyunsaturated fatty acids (82.78–85.52%). The total tocopherol content ranged from 117.29 to 156.67 mg/kg and mainly consisted of γ-tocopherol. Total phytosterols in the three oils ranged from 9.4 to 12.2 g/kg. Black quinoa seed oil had the highest phytosterols followed by red and white quinoas. The chemical profile of quinoa seed oils paralleled by their antioxidant and anticancer activities in vitro was positively correlated with the seed coat color. Black quinoa seed oil had the best antioxidant and anti-proliferation effect on HCT 116 cells by the induction of apoptosis in a dose-dependent manner, which may play more significant roles in the chemoprevention of cancer and other diseases related to oxidative stress as a source of functional foods.  相似文献   
533.
大孔吸附树脂分离纯化荔枝核黄酮类化合物的研究   总被引:8,自引:2,他引:6  
比较了D101、D3520、NKAII、AB-8、X-5、HPD-100、HPD-300、HPD-600等8种大孔吸附树脂对荔枝核中抗乙肝活性成分黄酮类化合物的吸附及解吸性能,筛选出效果较好的HPD-300树脂进行分离纯化实验研究。实验表明,HPD-300树脂能够有效地吸附和解吸荔枝核黄酮类化合物,并确定了最佳的吸附和解吸工艺参数。采用最佳的工艺条件分离纯化荔枝核黄酮类化合物,黄酮类化合物的含量由31%提高到82%。  相似文献   
534.
L-dopa, a dopaminergic agonist, is the gold standard for the treatment of Parkinson’s disease. However, due to the long-term toxicity and adverse effects of using L-dopa as the first-line therapy for Parkinson’s disease, a search for alternative medications is an important current challenge. Traditional Ayurvedic medicine has suggested the use of Mucuna pruriens Linn. (Fabaceae) as an anti-Parkinson’s agent. The present study aimed to quantify the amount of L-dopa in M. pruriens seed extract by HPLC analysis. The cytotoxicity and neuroprotective properties of M. pruriens aqueous extract were investigated by two in vitro models including the serum deprivation method and co-administration of hydrogen peroxide assay. The results showed the significant neuroprotective activities of M. pruriens seed extracts at a concentration of 10 ng/mL. In addition, the effects of L-dopa and M. pruriens seed extract on in vitro acetylcholinesterase activities were studied. M. pruriens seed extract demonstrated acetylcholinesterase inhibitory activity, while synthetic L-dopa enhanced the activity of the enzyme. It can be concluded that the administration of M. pruriens seed might be effective in protecting the brain against neurodegenerative disorders such as Parkinson’s and Alzheimer’s diseases. M. prurience seed extract containing L-dopa has shown less acetylcholinesterase activity stimulation compared with L-dopa, suggesting that the extract might have a superior benefit for use in the treatment of Parkinson’s disease.  相似文献   
535.
In this study, the volatile compound profiles of gurum seed oil were determined using two methods: supercritical CO2 extraction (SFE) and the screw press process (SPP). For volatile compounds extraction and identification, headspace solid-phase micro-extraction (HS-SPME) and GC–MS were used, respectively. A total number of 56 volatile compounds were revealed and identified in oil extracted by SFE, while only 40 compounds were detected in extracted oil by SPP. Acids, aldehydes, esters, ketones, furans, and other components were present in the highest ratio in oil extracted by SFE. In contrast, alcohols and alkenes were found in the highest proportion in oil extracted by SPP. In this study, it was observed that SFE showed an increase in the amounts of volatile compounds and favorably impacted the aroma of gurum seed oil. The results reveal that different extraction methods significantly impact the volatile components of gurum seed oil, and this study can help evaluate the quality of the oil extracted from gurum seeds.  相似文献   
536.
The antitumor effects of Coix lacryma-jobi L. var. ma-yuen Stapf. (adlay seed) ethanolic extract have been increasingly shown. This study aimed to investigate the beneficial effects of both the fractions and subfractions of adlay seed ethanolic extract on the human breast (MCF-7) and cervical (HeLa) cancer cell lines, as well as exploring their possible mechanisms of action. The ethanolic extracts were obtained from different parts of adlay seed, including AHE (adlay hull extract), ATE (adlay testa extract), ABE (adlay bran extract) and PAE (polished adlay extract). The results of a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl- tetrazolium bromide (MTT) assay showed that AHE-Ea and ATE-Ea showed significant growth inhibitory effects in a dose-dependent manner. The results also showed that the AHE-Ea-K, AHE-Ea-L, ATE-Ea-E and ATE-Ea-F subfractions inhibited cell proliferation, induced cell cycle arrest in the G0/G1 phase and decreased CDK4/Cyclin D1 protein expression. Finally, the extract activated caspase-3 activity and PARP protein expression, which induced MCF-7 and HeLa cell apoptosis. We then used liquid chromatography–mass spectrometry (LC/MS) to identify the potential active components., Quercetin showed an anticancer capacity. In conclusion, the AHE-Ea-K, AHE-Ea-L, ATE-Ea-E and ATE-Ea-F subfractions showed antitumor effects through the inhibition of MCF-7 and HeLa cell line viability, as well as inducing apoptosis and cell cycle arrest.  相似文献   
537.
采用改进后的顶部籽晶熔渗生长(RE+011 TSIG)工艺,通过在固相先驱粉中掺杂不同含量的MgO来有效地提高NdBCO籽晶的熔化温度,从而成功地制备出直径为32 mm的大尺寸单畴SmBCO超导块材.结果表明,MgO的掺杂对NdBCO超导块材的熔化温度有着明显的提高,随着固相先驱粉中MgO掺杂量的增加,Mg2+离子逐渐进入到Nd123相的晶格中,当掺杂量达到16 wt%时呈现出饱和状态,且NdBCO超导块材的熔化温度提高近18℃,可有效地抑制在制备SmBCO超导块材的过程中出现的NdBCO籽晶熔化现象.  相似文献   
538.
为对糯玉米种子热损伤粒进行无损快速鉴别并探索热损伤过程对糯玉米种子的影响,以糯玉米种子"京科糯2000"为例,用Videometer近紫外-可见-短波近红外多光谱成像仪分别以胚面向上和胚面向下方式采集糯玉米种子对照组及热损伤组多光谱成像数据,分别提取胚面向上胚部、胚面向上胚乳部、胚面向下胚乳部单点多光谱数据,并对胚面向上胚部和胚面向上胚乳部多光谱数据做初级融合;对多光谱数据进行基线校正预处理后计算各光谱数据样本标准差,进而通过光谱数据样本标准差的变化分析热损伤对糯玉米种子各部位的影响;基于多光谱数据采用偏最小二乘-判别分析算法建立糯玉米种子热损伤粒无损鉴别模型,对所建模型进行全交互验证,并与近红外光谱数据模型比较。结果表明,热损伤对糯玉米种子胚、胚乳有不同的影响,多光谱数据和近红外光谱数据表现出一致的变化趋势。采用多光谱数据建立热损伤粒鉴别模型,各模型前3主成分得分3D散点图中,对照组和热损伤组样品表现出一定的分离趋势,校正数据正确率在96%~100%之间,交互验证数据正确率在92%~100%之间,其中,糯玉米种子胚面向上胚部光谱和胚乳部光谱初级融合数据建模效果最好,校正数据正确率10...  相似文献   
539.
Cactus is a tropical fruit with a high nutritional value; however, little information is available regarding the comprehensive utilization of its byproducts. This study aimed to explore the composition and nutritional value of cactus fruit seed oil (CFO) and reveal the effects of ultrasound-assisted extraction and traditional solvent extraction on oil quality. Foodomics analysis showed that CFO extracted using a traditional solvent is rich in linolenic acid (9c12cC18:2, 57.46 ± 0.84 %), α-tocopherol (20.01 ± 1.86 mg/100 g oil), and canolol (200.10 ± 1.21 μg/g). Compared to traditional solvent extraction, ultrasound-assisted extraction can significantly increase the content of lipid concomitants in CFO, whereas excessive ultrasound intensity may lead to the oxidation of oils and the formation of free radicals. Analysis of the thermal properties showed that ultrasound had no effect on the crystallization or melting behavior of CFO. To further demonstrate the nutritional value of CFO, a lipopolysaccharide (LPS)-induced lipid metabolism imbalance model was used. Lipidomics analysis showed that CFO significantly reduced the content of oxidized phospholipids stimulated by LPS and increased the content of highly bioactive metabolites such as ceramides, thus alleviating LPS-induced damage in C. elegans. Hence, CFO is a functional oil with high value, and ultrasound-assisted extraction is advocated. These findings provide new insights into the comprehensive utilization of cactus fruits.  相似文献   
540.
刘思阳  白依凡  李伟 《无机化学学报》2019,35(11):2051-2056
通过加入晶种的方法降低在合成SAPO-11分子筛过程中有机胺类模板剂的含量从而减少对环境的污染。通过调节晶种及模板剂的含量,得到加入4%晶种、模板剂与Al2O3物质的量比值(ntemplate/nAl2O3)为0.6的条件下得到的晶体的形貌、结晶度等最好。分子筛负载Ni-Mo金属合成催化剂,以棕榈油加氢脱氧产物(HDO)为原料,在623 K下测得对生物航煤的选择性为66.1%,转化率为79.8%。  相似文献   
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