白簕愈伤组织培养条件优化及总黄酮含量测定

优化了白簕愈伤组织的继代培养条件并测定了白筋愈伤组织总黄酮含量.结果表明,继代的白簕愈伤组织在激素组合2,4-二氯苯氧乙酸(2,4-D)1.0mg/L+6-苄基氨基嘌呤(6-BA)0.6mg/L的MS基本培养基(Murashing and Skoog medium)中生长速度快,状态良好,避免了以往的严重褐化现象.按照白簕叶提取总黄酮的最佳提取工艺,采用微波辅助法提取白簕愈伤组织中的黄酮类化合物.分别以芦丁和金丝桃苷为对照,采用紫外分光光度法在260nm处测定总黄酮含量.结果表明,白簕愈伤组织提取总黄酮含量为29.347mg/g.高于白簕叶总黄酮含量.     

白簕叶总皂苷提取工艺和含量测定研究

采用微波辅助法提取白簕叶中的皂苷类化合物,通过正交实验确定了最佳提取工艺。以齐墩果酸为对照,采用紫外分光光度法在500nm处测定白簕叶中的总皂苷。最佳工艺条件：乙醇浓度70%,微波辐射30s,微波功率160W,固液比1∶10,间歇提取2次。按最佳工艺条件提取总皂苷含量为84.36mg/g。回归方程为：y=1.0167C＋0.0006,相关系数r=0.9998,精密度和稳定性试验RSD分别为0.033%和0.034%（n≥6）,平均加标回收率为99%,RSD=1.76%（n=6）。用齐墩果酸标准品,采用紫外分光光度法,操作简便,结果准确,灵敏度高,重复性好,为白簕叶中总皂苷含量测定的一种切实可行的方法。     

空心莲子草总黄酮的提取工艺

确定空心莲子草总黄酮最佳提取工艺.采用微波辅助法提取空心莲子草中的黄酮类化合物,通过正交实验确定了最佳提取工艺.以芦丁为对照,采用紫外分光光度法在260nm处测定其中的总黄酮.最佳工艺条件:乙醇浓度40%,固液比1:20,微波辐射40s,微波功率320W,间歇提取2次.按最佳工艺条件提取总黄酮含量为30.012mg/g.回归方程为;y=33.21C+0.0106,相关系数r=0.9998,精密度试验RSD分别为1.1461(n≥6),平均加样回收率为99%,RSD=2.43%(n=6).样品的稳定性试验RSD为0.048%(120min).选择的最佳工艺对提取空心莲子草总黄酮确为最佳.用芦丁标准品,采用紫外分光光度法,操作简便,结果准确,灵敏度高,重复性好,为空心莲子草中总黄酮含量测定的一种切实可行的方法.     

积雪草总黄酮提取工艺和含量测定研究

确定积雪草总黄酮最佳提取工艺和含量测定方法,采用微波辅助法提取积雪草中的黄酮类化合物,通过正交实验确定了最佳提取工艺.分别以槲皮素和山奈酚为对照,采用紫外分光光度法在320nm处测定积雪草全草中的总黄酮.最佳工艺条件:提取次数3次,辐射时间20s,固液比1:10,功率480W.按最佳工艺条件提取总黄酮含量为8.40mg/g.回归方程为(槲皮素):y=29.993C+0.027,相关系数r2=0.9982,精密度和稳定性试验RSD分别为0.265%和0.172%(n≥6),平均加样回收率为99%,RSD=1.51%(n=5).回归方程为(山奈酚):y=36.928C+0.0178,相关系数rz=0.9991,精密度和稳定性试验的RSD分别为0.231%和0.190%(n≥6),平均加样回收率为99%,RSD=0.714%(n=5),样品的稳定性试验RSD为0.218%(60min).选择的最佳工艺对提取积雪草全草总黄酮确为最佳.用槲皮素或山奈酚标准品,采用紫外分光光度法,操作简便,结果准确,灵敏度高,重复性好,为积雪草全草中总黄酮含量测定的一种切实可行的方法.     

女贞叶中总黄酮含量的测定及抗氧化活性

以70％乙醇为溶剂超声提取女贞叶中总黄酮,以表儿茶素为对照品,分光光度法测定其含量;用清除DPPH来评价女贞叶总黄酮抗氧化活性.在510nm处表儿茶素浓度在0.005-0.03mg/mL范围内线性关系良好(r=0.9994).女贞叶中总黄酮含量为39.5mg/g,平均加标回收率为101.63％ (RSD=1.96％),精密度高(RSD=0.78％),重现性好(RSD=1.96％),可作为测定女贞叶中总黄酮含量的一种好方法.抗氧化实验结果表明,女贞叶总黄酮具有较强的清除DPPH自由基的能力,其清除效果在一定范围内随着总黄酮质量浓度的增加而增强.     

正交设计优选维药恰玛古总黄酮的提取工艺

确定恰玛古总黄酮的最佳提取工艺.以乙醇为溶剂,采用索氏提取,紫外-可见分光光度法测定恰玛古中总黄酮的含量,通过稳定性、精密度和回收率实验检验了该方法的可靠性和重现性.对照品溶液和供试品液均在510nm处有最大吸收.回归方程为A=0.02054C+0.07628,r=0.9998(0-24μg·mL-1);优选的提取工艺为30倍原料重、75％乙醇、提取时间120min.平均总黄酮的含量为2.805％,平均回收率为100.88％,精密度和加样回收率的RSD分别为0.46％和2.26％.本实验操作简便,灵敏度高,结果准确,可用于恰玛古总黄酮的含量测定.     

柳芽中总黄酮含量的测定

以芦丁为对照品,采用超声辅助法提取柳芽中的总黄酮,分光光度法测定其含量.样品浓度在0-0.3mg·mL-1范围内线性关系良好,相关系数r=0.9999,柳芽中黄酮含量为3.08％,该方法简便、准确,可用于柳芽中总黄酮的含量测定.     

大青叶提取物中总黄酮含量测定

建立大青叶中总黄酮含量测定方法.以超声辅助、70％乙醇提取大青叶总黄酮,采用紫外可见分光光度法对大青叶总黄酮进行测定.芦丁标准溶液线性方程为:A=0.01087C-0.0005833,r=0.9999.加标回收率为98.00％,相对标准偏差为1.45％.方法简便、快速、准确,且稳定性好,适用于测定大青叶总黄酮的含量.     

穿心莲中总黄酮含量的测定

以芦丁为对照品,NaNO2-Al(NO3)3-NaOH体系为显色剂,利用分光光度法测定了穿心莲中的总黄酮含量.确定了总黄酮提取方法、显色剂浓度和显色时间等.回归方程为A=0.00652 11.0329C,相关系数r=0.9997.平均回收率为104.20%,RSD=1.85%(n=5).本法操作简便,可行,重现性好.     

槐枝中总黄酮的含量测定

采用索氏提取法提取槐枝中的总黄酮,芦丁为对照,分光光度法测定其含量。样品浓度在16.104—96.624μg.mL-1范围内线性关系良好,相关系数r=0.9996。该方法简便、准确,可用于槐枝中总黄酮的含量测定。     

Nonequilibrium statistical mechanics. I. Mathematical formalism. Theorem of N. S. Krylov

Based on an algebraic formulation of quantum mechanics we introduce concepts playing a fundamental role in the constructionof the statistical mechanics of systems having direct classical analogs. We give the definition of a macrostate, mixing in the quantum version, and also demonstrate the existence of an upper bound to the relaxation time for an isolated system. It is shown that the theory constructed here contains both quantum and classical mechanics as limiting cases, but these two cases are not reducible to each other. The existence of a transition range not describable by the Schrodinger equation is noted.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 11, pp. 42–45, November, 1981.     

Analysis of R. P. Smith's and D. C. Parris-R. B. Mclellan's carbon diffusivity data

A phenomenological model is proposed to account for the variation of carbon diffusivityD(N₁) with composition in austenite. This model is based on Parris-McLellan's statement that the increase ofD(N₁) with carbon concentrationN ₁ is due to the increase in chemical driving force. The gradient of the carbon activity in Wagner's and in Zupp-Stevenson's interpretation is presumed to be the intrinsic driving force. The predictions of the model are compared with carbonD(N₁) values both with [1] and without [5] a chemical concentration gradient. TheD(0) values and the carbon-carbon interaction coefficients ₁ are calculated by the use of the least squares method from the experimental data. The application of Zupp-Stevenson's definition of the activity coefficient ₁ results in a better fit of the theory to the experimental data.     

N.M.R. spectra of oriented molecules

The phosphorescence spectra of anthracene-h₁₀ and -d₁₀ have been studied in a number of glasses and crystalline matrices. The line widths are very matrix dependent and they range from about 150 cm^-1 to 1 cm^-1 in n-heptane. There is a correlation between the line width and the wavenumber position of the origin. A study of the relative intensities of fluorescence and phosphorescence from various sites in Shpolskii matrices has shown that the intersystem crossing rate is site dependent. It is postulated that this involves the relative energies of the singlet state and a triplet state, nearly degenerate with it, which are site dependent.     

E.S.R. spectroscopy of non-cyclic enones

The π-bond model is applied to the calculation of the proton chemical shifts of a range of benzenoid hydrocarbons. The simple calculations give results which compare well with experiment and with calculations based on the ring current model. Least squares fitting of the predicted chemical shifts to the observed values can give an indication of the occurrence of local aromatic groups in larger molecules. This procedure also yields an empirically adjusted estimate of the anisotropy in the molar magnetic susceptibility from the experimental proton chemical shifts. A simple criterion for aromaticity is also given. The overall results suggest that there is no need to associate a special ring current attribute to π conjugation in aromatic molecules.     

N.M.R. spectra of oriented molecules

By analysis of the high resolution N.M.R. spectrum of 1,2,2,3-tetrachloro-propane partially oriented in a liquid-crystal solvent, it has been shown that this molecule takes up predominantly the G′G′ type of conformation.     

N.M.R. relaxation study of crystalline quinuclidine

Transient signals in the fluorescence intensity induced by microwaves can be used to acquire quantitative information on the molecular rates of populating and depopulating of the lowest triplet state of organic molecules. This method seems especially promising when the molecule emits no detectable phosphorescence.

Part of this paper concerns the introduction of an appropriate mathematical model for describing the fluorescence transients. The model is formulated in conjunction with a specific series of experiments from which one may evaluate the molecular quantities in a systematic way. The kinetics of the lowest triplet state of free base porphin (H₂P) are determined explicitly by this method.

In the discussion the results for H₂P are compared with those for Zn porphin. A satisfactory qualitative explanation based on the theory of radiationless transitions can be given for the great difference in behaviour of these two porphyrin molecules.

Short attention is given to effects due to the photochemical shift of the two H atoms in the centre of H₂P, which is proven to occur even at a temperature as low as 1·3 K.     

N.M.R. study of solid perfluorocyclobutane

spin-lattice relaxation times and linewidth measurements for fluorine nuclei in solid perfluorocyclobutane are presented. The results are discussed in terms of D _2d molecular species performing fast internal motion. The relaxation measurements corroborate the existance of four solid-solid phase transitions and give some insight into their nature. The activation energies for molecular reorientation and self-diffusion processes are found to be 28·0 and 32·2 kJ mol^-1, respectively.