超声辅助提取血柚皮多糖工艺优化及其对自由基的清除作用

以漳州血柚皮为原料,采用超声波辅助热浸提法对血柚皮多糖进行提取,并以苯酚—硫酸法测定多糖提取率.分别对超声功率、超声温度、料液比、超声时间进行单因素和正交试验,并通过极差、方差分析对提取过程显著影响提取率的因素进行统计分析.结果表明,超声波辅助热浸提取血柚皮中多糖的最佳工艺条件为:超声功率80 W、超声温度65℃、料液比1∶30、超声时间70 min.该工艺条件下血柚皮多糖的提取率为18.51%,该方法的提取率比无超声波辅助的热浸提法提高了2.24%.以抗坏血酸为对照,考察了其羟自由基清除能力、DPPH自由基清除能力以及超氧阴离子自由基清除能力,结果显示,多糖对自由基的清除能力很强,但其对各自由基的清除能力均小于抗坏血酸.表明血柚皮多糖作为天然的抗氧化剂有一定的应用前景.     

超声辅助提取血柚皮多糖工艺优化及其对自由基的清除作用

以漳州血柚皮为原料,采用超声波辅助热浸提法对血柚皮多糖进行提取,并以苯酚—硫酸法测定多糖提取率.分别对超声功率、超声温度、料液比、超声时间进行单因素和正交试验,并通过极差、方差分析对提取过程显著影响提取率的因素进行统计分析.结果表明,超声波辅助热浸提取血柚皮中多糖的最佳工艺条件为:超声功率80 W、超声温度65℃、料液比1∶30、超声时间70 min.该工艺条件下血柚皮多糖的提取率为18.51%,该方法的提取率比无超声波辅助的热浸提法提高了2.24%.以抗坏血酸为对照,考察了其羟自由基清除能力、DPPH自由基清除能力以及超氧阴离子自由基清除能力,结果显示,多糖对自由基的清除能力很强,但其对各自由基的清除能力均小于抗坏血酸.表明血柚皮多糖作为天然的抗氧化剂有一定的应用前景.     

响应面法优化白番红花球茎多糖提取工艺及其抗氧化活性研究

在单因素试验的基础上,以白番红花球茎多糖提取率为响应值,对超声功率、超声时间、液料比三因素进行响应面法优化试验,并通过白番红花球茎多糖对DPPH自由基、超氧阴离子自由基、羟基自由基、ABTS自由基的清除能力,来研究白番红花球茎多糖的抗氧化活性.白番红花球茎多糖的提取最佳工艺条件为：超声功率为428 W、超声时间为45 min、液料比为57.8∶1(mL·g^-1),多糖实际提取率为7.54%.白番红花球茎多糖对DPPH自由基、超氧阴离子自由基、羟基自由基、ABTS自由基均有清除作用,其清除率最高分别可达到78.5%、57.9%、45.3%、79.8%.响应面法优化超声波提取白番红花球茎多糖的工艺合理可行,并且白番红花球茎多糖具有较强的抗氧化活性.     

满天星水溶性多糖提取及抗氧化活性研究

考察了水提法提取满天星水溶性多糖的工艺条件和体外抗氧化活性．采用L9（3^4）正交试验方法,研究了料液比、浸提温度、浸提时间、提取次数对提取效率的影响．在选定的工艺条件下,料液比和提取温度对满天星水溶性多糖提取率的影响大于提取时间、提取次数的,料液比和提取温度为主要影响因素;最佳工艺条件为料液比1：20、提取温度80℃、提取时间1．5h、提取次数三次．在最佳工艺条件下测得满天星粗多糖提取率为1．83％．体外抗氧化活性试验表明,满天星水溶性多糖能有效地清除DP—PH自由基,当满天星多糖浓度在0．30mg／mL以上时,对DPPH自由基的清除率超过81％．     

正交优化知母黄酮超声提取工艺及抗氧化研究

[目的]研究知母根茎总黄酮的超声波提取工艺并对体外抗氧化性进行测定.[方法]考察以乙醇为溶剂时液料比、超声温度、超声功率、超声时间对提取率的影响,并用正交法筛选最佳工艺.[结果]实验表明:各因素对知母总黄酮萃取得率的影响由大到小依次为液料比、超声功率、超声温度、超声时间;最佳提取工艺条件为:液料比40∶1(mL/g)、超声温度60℃、超声时间45min、超声功率150 W,此条件下总黄酮提取率高达1.53%.[结论]由自由基清除试验可知,知母总黄酮抗氧化能力与其浓度呈正向量效关系,对·OH和DPPH·的清除效率分别可达60.2%,76.5%,显示其具较强的体外抗氧化能力.     

冬瓜多糖的超声波辅助提取及其抗氧化活性研究

研究冬瓜多糖的超声波辅助提取工艺及体外抗氧化活性。在单因素试验的基础上,探究料液比、提取时间、提取功率对冬瓜多糖提取率的影响,然后以正交试验确定其适宜提取工艺。通过对超声波辅助提取所提得冬瓜多糖的DPPH自由基、羟基自由基、超氧阴离子自由基的清除能力进行测定,来表征冬瓜多糖的体外抗氧化活性。结果表明:超声波提取时间及料液比对冬瓜多糖提取率的影响显著(P<0.05),超声波辅助提取冬瓜多糖适宜工艺条件为,料液比1∶40,超声波提取时间40 min,提取功率380 W,此条件下冬瓜粗多糖得率为13.15%,相比于热水浸提法,得率提高50%以上,提取时间缩短1/2。当冬瓜多糖浓度为5 mg/mL时,其对DPPH自由基、羟基自由基、超氧阴离子自由基的清除率分别为77.91%、99.64%、74.48%。超声波辅助提取能显著提高冬瓜多糖的提取效率,且冬瓜多糖具有较好的抗氧化活性。     

响应面优化铁观音茶末茶多糖提取及清除自由基作用

为了探究福建安溪铁观音茶末茶多糖的最优提取工艺及其体外清除自由基的作用,考察单因素浸提温度、液料比和浸提时间对茶末茶多糖提取率的影响,采用响应面分析法优化铁观音茶末茶多糖的提取工艺,并测定茶多糖清除·DPPH的能力.结果表明:在液固比80∶1(mL/g),浸提时间130 min,浸提温度90℃的条件下,茶多糖的提取率可达9.95%;体外清除自由基试验表明,铁观音茶末茶多糖具有较强的·DPPH自由基清除能力.     

高压热水提取灵芝多糖及对其抗氧化活性的影响

以灵芝子实体超微粉为原料,研究了提取温度、提取时间和料液比在高压热水条件下对灵芝多糖提取以及多糖提取液对DPPH自由基清除率的影响,并采用正交试验优化了灵芝多糖高压热水提取工艺。确定较优工艺条件为料液比1∶50g/mL、提取温度125℃下提取30min,一次高压热水提取灵芝多糖提取率达到4.54%。抗氧化实验结果表明,灵芝多糖对 DPPH 自由基有一定的清除能力,且与多糖质量浓度存在一定的量效关系。     

油茶蒲多糖的提取工艺优化及其抗氧化活性

以油茶蒲为材料，采用响应面法结合Box-Behnken 实验设计，对热水法提取油茶蒲多糖的工艺条件进行优化，考察提取时间、温度、液料比3个因素对多糖提取率的影响.并初步探究油茶蒲多糖体外抗氧化活性.结果表明：在提取时间150 min，提取温度85 ℃，液料比32 mL g－1时，多糖提取率最佳，为10.49 ± 0.21 % (n＝4).在浓度0.6 mL g－1时DPPH自由基清除率可达到90%，总还原能力在1.4 mL g－1时与同浓度Vc效果相近，表明油茶蒲多糖具有较好的抗氧化能力.     

超声法提取枸杞多糖工艺优化

采用超声法提取枸杞多糖,考察了料液比、超声功率、超声时间和提取温度四个因素对枸杞多糖提取率的影响。结果最佳提取工艺条件为:料液比1∶50、超声功率60 W、超声时间15 min,提取温度90℃。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of