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71.
72.
一阶混合型积分微分方程的周期边值问题 总被引:1,自引:0,他引:1
在有一般化的上下解的条件下,研究了一阶混合型积分微分方程的周期边值问题的可解性和最小最大解的存在性。讨论基于迭合度方法,单调迭代方法和新的比较定理。 相似文献
73.
八角茴香与其伪品莽草的红外光谱三级鉴定研究 总被引:2,自引:0,他引:2
采用红外光谱三级鉴定的方法区分和鉴别了八角茴香及其伪品莽草。红外光谱三级鉴定即依次采用一维红外光谱、二阶导数谱和二维相关红外光谱,分辨率逐渐提高,谱图的差别也进一步放大。一维谱图中,两者整体峰形比较相似,但在3 400 cm-1附近八角茴香只出现一个特征峰3 392 cm-1,而莽草则出现3 482和3 387 cm-1两个特征峰。二阶导数谱在850~1 180 cm-1波段八角茴香的几个强峰峰强相对比较接近,其中1 015 cm-1为图中最强峰,而莽草的最强峰在1 070 cm-1附近;在1 180~1 500 cm-1波段八角茴香在1 469,1 454,1 442 cm-1附近的3个特征峰峰强明显强于1 292,1 276,1 266 cm-1附近的特征峰,而莽草则刚好相反。二维相关红外光谱中差异更明显,850~1 165 cm-1波段八角茴香在主对角线上的自动峰较强峰出现在1 153和1 000 cm-1,而莽草峰强较强的自动峰出现在911和878 cm-1;1 165~1 500 cm-1波段八角茴香呈现2个自动峰,而莽草则出现5个自动峰。可见红外三级鉴定方法是一种快速有效的鉴定中药材的方法。 相似文献
74.
75.
Hyejin Hyeon Ho Bong Hyun Boram Go Sung Chun Kim Yong-Hwan Jung Young-Min Ham 《Molecules (Basel, Switzerland)》2022,27(1)
Magnolia flower buds are a source of herbal medicines with various active compounds. In this study, differences in the distribution and abundance of major essential oils, phenolic acids, and primary metabolites between white flower buds of Magnolia heptapeta and violet flower buds of Magnolia denudata var. purpurascens were characterised. A multivariate analysis revealed clear separation between the white and violet flower buds with respect to primary and secondary metabolites closely related to metabolic systems. White flower buds contained large amounts of monoterpene hydrocarbons (MH), phenolic acids, aromatic amino acids, and monosaccharides, related to the production of isoprenes, as MH precursors, and the activity of MH synthase. However, concentrations of β-myrcene, a major MH compound, were higher in violet flower buds than in white flower buds, possibly due to higher threonine levels and low acidic conditions induced by comparatively low levels of some organic acids. Moreover, levels of stress-related metabolites, such as oxygenated monoterpenes, proline, and glutamic acid, were higher in violet flower buds than in white flower buds. Our results support the feasibility of metabolic profiling for the identification of phytochemical differences and improve our understanding of the correlated biological pathways for primary and secondary metabolites. 相似文献
76.
Arpamas Chariyakornkul Waristha Juengwiroj Jetsada Ruangsuriya Rawiwan Wongpoomchai 《Molecules (Basel, Switzerland)》2022,27(2)
The indigenous purplish red fruit, Cleistocalyx nervosum var. paniala (CN), is grown in northern Thailand. The aqueous extract of CN pulp is known to exhibit antioxidant and anticarcinogenic properties. To search for an antioxidant fraction separated from CN, various hydroalcoholic extractions were performed. The acidified ethanolic extract of CN obtained from 0.5% (v/v) citric acid in 80% (v/v) ethanol yielded greater polyphenol content and DPPH radical scavenging activity when compared with other hydroethanolic extracts. Cyanidin-3-glucoside is a major anthocyanin present in the acidified ethanolic extract of CN (AECN). At a dose of 5000 mg/kg bw, an anthocyanin-rich extract was found to be safe when given to rats without any acute toxicity. To examine the hepatoprotective properties of AECN, an overdose of acetaminophen (APAP) was induced in a rat model, while silymarin was used as a standard reference. The administration of AECN at a dose of 300 mg/kg bw for 28 days improved hepatocyte architecture and modulated serum alanine aminotransferase levels in APAP-induced rats. Furthermore, it significantly decreased serum and hepatic malondialdehyde levels but increased hepatic glutathione content, as well as glutathione peroxidase and UDP-glucuronosyltransferase activities. In conclusion, AECN may effectively reduce oxidative stress induced acute hepatotoxicity in overdose APAP-treated rats through the suppression of oxidative stress and the enhancement of the antioxidant system in rat livers. 相似文献
77.
Let be its decomposition into a product of powers of two distinct primes, and be the residue class ring modulo h. In this paper, we determine the Smith normal forms of matrices, compute the number of the orbits of matrices under the action of the group and the length of each orbit over . As applications, we determine the clique number, the independence number and the chromatic number of the bilinear forms graph, construct a family of association schemes by using matrices and compute the intersection numbers and the character table over for . 相似文献
78.
Two new compounds,oleanolic acid 28-O- β-D-glucopyranosyl-3-O-α-L-arabinopyranosyl-(1→3)-(6′-butyl ester)-β-D-glucuropyranoside 1,oleanolic acid 28-O-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside 2 have been isolated from the roots of Hemsleya penxianensis var.gulinensis.Their structures were determined on the bases of the spectral and chemical evidences. 相似文献
79.
R.E. Stong 《Topology and its Applications》1985,19(2):169-188
Being given a closed manifold Mn, there are involutions (X2n, T) on closed manifolds of twice the dimension having fixed point set M. Kulkarni defined the deficiency of M for a class of involutions to be for all involutions (X, T) in the class. This paper exhibits manifolds for which the deficiency is positive for all involutions and studies the deficiencies for other classes. 相似文献
80.
以滇重楼的根茎为实验材料,重楼甾体总皂甙的提取率为评价指标,运用L16(4^5)正交试验,考察了皂甙浸出过程中的浸泡时间、乙醇浓度、超声剂量、粗粉质量与浸泡用乙醇体积之比4个因素在4个水平下的工艺过程,筛选出了最佳提取工艺。实验结果表明:粗粉(0.45mm粒径)用30%的乙醇溶液浸泡36h后,超声30min,粗粉质量与(浸泡)乙醇的体积比1:15为最佳提取条仲,重楼甾体总皂甙的提取率为9.50%。以近红外漫反射光谱技术为在线监控手段,利用模式识别方法对AB-8树脂分离精制过程中的吸附、杂质洗脱和甾体总皂甙解吸洗脱等工艺过程进行了在线质量监控方法研究,建立了优化的质量可控的分离纯化方法。 相似文献