仙人掌多糖的分离纯化研究进展

仙人掌多糖具有明显的抗衰老、消炎、抗癌和降血糖等作用.文章综述了仙人掌多糖的多种提取和纯化及纯度鉴定的方法,以期为仙人掌多糖的进一步研究开发提供参考.     

竹叶多糖的提取工艺

目的：筛选竹叶多糖提取优化的最佳工艺.方法：以竹叶多糖为工艺筛选指标,采用正交实验设计方法筛选最佳提取工艺及其条件.结果：竹叶多糖最佳提取工艺为石油醚回流2 h,滤渣用95%乙醇回流2 h,再用30倍量的水回流3次浸提多糖.用Sevage法除蛋白,加入乙醇使含醇量为80%,于冰箱静置12 h,得多糖沉淀.采用优化后的工艺提取竹叶多糖粗品的得率约0.51%.结论：采用该提取工艺,竹叶多糖的提取率较高.     

响应面法优化黄精叶多糖水提工艺

为建立与优化黄精叶多糖提取工艺,采用水提法提取黄精叶多糖,利用蒽酮-硫酸法测定多糖含量.以多糖提取率及出膏率为试验指标,在单因素试验基础上,通过三因素三水平Box-Behnken响应面法(RSM)优化黄精叶中多糖的提取条件.结果显示黄精叶多糖最佳提取工艺为:提取温度75℃,液料比15∶1,提取时间2.5 h.在此条件下,药材的出膏率为(47.65±0.16)%、多糖得率为(7.21±0.073)%.该水提工艺条件稳定可行,多糖得率较高.     

假酸浆多糖的酶法提取及纯化工艺的研究

采用正交设计法进行试验,以多糖的提取率作为评价指标,用木瓜蛋白酶法从假酸浆籽中提取假酸浆多糖.确定了木瓜蛋白酶的最佳提取工艺为:酶用量3%,p H=7.5温度55℃,提取时间50min.多糖提取率为6.02%.再将提取的粗多糖经脱蛋白、脱色等一系列工艺进行纯化,确定了假酸浆多糖的最佳纯化工艺,在此条件下测得多糖的含量为80.6%,脱蛋白率为77.33%,脱色率为70.2%.     

响应面法优化发酵藤茶黄酮和多糖的提取工艺

根据单因素试验的结果,采用响应面分析法优化藤茶黄酮和多糖的提取工艺.结果表明:最佳提取工艺条件为提取温度96℃,时间1.6h,料液比1∶21.在此优化工艺条件下,总黄酮和多糖的提取得率分别为22.94%和2.13%.藤茶黄酮和多糖的优化提取工艺有利于藤茶资源的综合开发利用.     

米邦塔仙人掌胶多糖化学组成的检测

目的研究米邦塔仙人掌胶多糖的物理及化学性质。方法采用水提—醇沉法提取米邦塔仙人掌中的胶多糖,用气相色谱分析其单糖的组成及摩尔比,测定胶多糖的总糖含量及糖醛酸含量,分析其紫外及红外光谱。结果其多糖的单糖组成为:鼠李糖、岩藻糖、阿拉伯糖、木糖、甘露糖、葡萄糖、半乳糖、葡萄糖醛酸及半乳糖醛酸,其物质的量比为13.49∶1∶61.83∶26.37∶3.49∶6.70∶66.76∶6.68∶29.81。米邦塔仙人掌的总糖含量为91.10%,糖醛酸含量为18.78%。紫外光谱表明该多糖可能含有糖蛋白,红外光谱表明其具有多糖特征吸收。结论米邦塔仙人掌多糖是一种主要由阿拉伯糖和半乳糖组成,并含有少量的鼠李糖、木糖和半乳糖醛酸以及微量的甘露糖、葡萄糖、岩藻糖和葡萄糖醛酸的胶性多糖,其糖含量测定为91.10%,可能含有少量糖蛋白。     

水浸法提取刺梨中多糖

为了简化刺梨多糖的提取工艺,达到节能、省时、方便的目的,用水提法提取刺梨多糖,探讨乙醇质量分数、提取温度、加热时间和料液比对多糖提取率的影响.采用正交实验优化工艺,以多糖提取率为评价指标,用蒽酮硫酸法测定多糖含量.水提法的最佳工艺条件为温度75 ℃,时间1 h,料液比1∶40,乙醇质量分数0%.在此条件下刺梨多糖的得率为4.7%.     

山药多糖的提取测定研究

目的 研究山药中多糖的提取工艺.方法 采用水浸法从鲜山药中提取多糖,通过单因素试验研究料液比、提取温度、提取时间对粗多糖提取量的影响.结果 优化工艺条件为料液比为1 g:9 mL,提取温度为70℃,浸提时间为3 h,此时多糖提取量可达0.905%.结论 采用水提法提取多糖量比文献所述增加了近2.7倍.     

响应面法优化窄叶鲜卑花叶片多糖提取工艺

为优化窄叶鲜卑花多糖提取工艺,在单因素试验的基础上,以窄叶鲜卑花叶片多糖得率为响应值(Y),以料液比(A)、提取温度(B)、提取时间(C)、超声功率(D)为4个自变量进行响应面法试验。结果表明:窄叶鲜卑花叶片多糖最佳提取工艺料液比为1∶16 g/m L,提取温度为62℃,提取时间为132 min,超声功率为64%。此工艺提取窄叶鲜卑花多糖得率预测值为21. 25%,实测多糖得率为21. 47%,与预测值的误差为0. 22%。因此,通过响应面法得到的工艺参数具有较高的准确度与实用性。     

青海豌豆多糖提取工艺的研究

以青海豌豆为原料,采用正交试验法对豆渣中水溶性豌豆多糖的提取工艺进行研究.结果表明,豌豆多糖提取的最佳条件为提取温度80℃,固液比1∶10,提取时间4.5h×3.在最佳提取工艺条件下,豌豆多糖的提取率为48.67%.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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