不同温度条件下溶剂循环溶解-析出提取杜仲胶

在杜仲树中杜仲胶以晶体微粒的形式存在,必需用溶剂提取或机械破坏植物组织来获取。虽然溶剂法的效率更高,但溶剂的消耗量大,污染环境严重。我们的研究发现,杜仲胶在热的石油醚中（约80℃）有很高的溶解度,冷却到40℃时有胶丝析出,当温度降到-20℃以下,杜仲胶几乎能较完全从石油醚中析出,回收的溶剂可继续用于下一次杜仲胶的提取,溶剂可循环使用。由于其他杂质仍以溶解态保留在溶剂中,回收的杜仲胶纯度高。此外,整个实验方法的溶剂损失少,对环境的污染小,制备方法简便。     

聚焦微波助脱除纤维素提取杜仲籽壳中杜仲胶

本研究采用聚焦微波提取法先脱除杜仲籽壳中的纤维素,再用溶剂提取杜仲胶。用实验因子设计优化了聚焦微波提取条件,从三个水平考察了四个因子,即微波辐照时间、碱液浓度、溶剂用量及微波功率对纤维素脱除效率的影响。脱除纤维素后的杜仲材料用石油醚为溶剂提取杜仲胶。结果表明:聚焦微波辐照脱除杜仲籽壳纤维素的优化条件为:辐照时间:20 min;氢氧化钠浓度:12.5%;溶剂用量:17.5 m L/g;微波功率:70%。与常规法碱提法提取杜仲胶相比,聚焦微波助提法提取率高,单次提取率达64.18%,提取时间短,一次提取需时小于3 h,而常规法约需30 h。两种方法所获产品纯度相差不大,显示了聚焦微波助提法提取杜仲胶的高效能。     

酶水解杜仲纤维素细胞壁及长丝杜仲胶的提取

绝大多数现有的杜仲胶提取方法都需要将杜仲皮和杜仲叶粉碎,降低了杜仲胶的弹性、韧性、抗拉强度.为了获得长丝杜仲胶,研究了纤维素酶对杜仲纤维素细胞壁水解、杜仲叶表面的角质层的去除以及长丝杜仲胶的提取.发现1%氢氧化钠在70 ℃条件下能除去杜仲叶表面阻挡纤维素酶作用的角质层,石油醚是一种十分理想的提取杜仲胶的溶剂.纤维素酶在pH为4时,50 ℃条件下能充分地水解纤维素细胞壁,提高了细胞的通透性,使得石油醚(60～90 ℃)可溶解出高聚合度的长丝杜仲胶,并且使杜仲胶的回收率由原来的2.5%提高了3%以上,拉伸强度也由粉碎样的0.02 MPa提高到60.5 MPa,断裂伸长率由～0%提高到24%,撕裂强度由0.5 kN/m提高到36 kN/m.活性碳能很好地回收石油醚中所溶解的脂溶性天然化学成分,提高了溶剂循环使用的溶解能力.     

乙酸预处理杜仲果壳提取杜仲胶

以盐酸为催化剂的条件下,乙酸预处理杜仲果壳,石油醚为溶剂索氏提取杜仲胶。考察乙酸浓度、预处理温度、预处理时间及催化剂的量对杜仲胶提取率的影响,并用傅里叶红外光谱仪(FT-IR)、热重分析仪(TG)对提取的杜仲胶进行表征。结果表明:乙酸预处理杜仲果壳不会破坏杜仲胶的结构,能有效提高杜仲胶的提取率。乙酸预处理杜仲果壳工艺条件:在固液比1∶12.5(g/m L)、催化剂盐酸用量0.35%(体积分数)条件下,用80%(体积分数)乙酸溶液在100℃下预处理3 h,石油醚索氏提取杜仲胶,杜仲胶提取率为15.17%。     

栽培方式对杜仲皮次生代谢物含量的影响

采用叶林和乔林两种栽培模式对杜仲定向培育,并分别对杜仲皮次生代谢物含量进行了测定.结果表明:在不同的栽培模式下,杜仲皮中次生代谢物的含量存在差异,杜仲醇和杜仲胶的含量,乔林皮高于叶林皮;京尼平甙酸、绿原酸、桃叶珊瑚甙的含量则是叶林皮高于乔林皮;总黄酮的含量随提取溶剂的不同而有高有低.对杜仲皮进行不同的预处理和选用不同的提取溶剂,能改变提取得率,但是,叶林皮与乔林皮次生代谢物含量变化趋势基本不变,说明栽培方式对杜仲皮次生代谢物有一定影响.     

真菌联合稀碱预处理杜仲叶提取杜仲胶的工艺研究

以杜仲干叶为原料,经稀碱和绿色木霉联合处理以除去杜仲表面覆盖的角质层,同时洗脱一些可溶性杂质,并且破坏杜仲叶的细胞壁与纤维结构,再以石油醚作为提取溶剂,得到粗胶再经丙酮浸洗获得杜仲精胶。用0.45%NaOH在75℃下除去杜仲叶表面的角质层,并且同时脱除一些可溶性活性成分(如:多糖、黄酮类、京尼平苷等),之后得杜仲叶干燥,利用绿色木霉去破坏杜仲叶的细胞壁与纤维结构,在85℃条件下以石油醚作为提取溶剂提取杜仲胶。最后,经测得未处理前杜仲叶中的杜仲胶的含量为1.78%,0.45%NaOH稀碱预处理后含量为3.16%,绿色木霉发酵后含量为4.36%。预处理前,有机溶剂一次提取率为0.73%,纯度为83.7%。稀碱与真菌联合预处理后一次提取率为2.85%,纯度为96.6%。本工艺以稀碱与绿色木霉共同作用,减少了有机溶剂的用量,与传统工艺相比,更加的绿色环保,安全有效,为杜仲胶的提取提供了科学有效的依据。     

采用滤袋技术快速测定杜仲叶片中杜仲胶含量

采用滤袋技术依据减重法原理测定了杜仲叶片中杜仲胶含量。通过正交设计比较了不同滤袋孔径、样品量和提取时间对提取效果的影响,并采用该方法比较了同一产地不同品种、同一品种不同产地的杜仲叶中胶含量的差异。结果表明,不同孔径的提取效果差异显著(F=3.685,p=0.043),样品量和提取时间对提取效果无显著影响。适宜的测定条件是样品量0.1 g、滤袋孔径25μm/10μm、提取时间60 min。滤袋法测得的‘华仲6号’胶含量为4.49%,传统碱煮法为3.64%。同一产地不同品种、同一品种不同产地的杜仲叶中胶含量差异极显著(F=92.689,P=0.001),其中郑州的‘华仲11号’含量最高,平均为7.00%,灵宝的‘华仲12号’含量最低,为4.28%。生产杜仲胶的原料应标明品种、产地以及树龄,这样有助于合理评估预期产量和生产成本。     

杜仲橡胶合成相关酶基因HMGR的克隆与表达分析

为解析HMGR基因在杜仲橡胶生物合成中的作用,本研究以杜仲良种华仲6号叶片和果皮为材料,参考杜仲基因组和转录组数据,克隆了杜仲HMGR基因,命名为Eu HMGR,全长1770 bp,编码590个氨基酸。实时荧光定量PCR测定结果显示,EuHMGR基因在果皮中的表达量于5月中旬达到最大值,而在叶片中的最大值出现在7月中旬。通过索氏提取测定相应时期果皮和叶片的含胶量表明,果皮中的含胶量从4月中旬到5月下旬迅速增加,而叶片中的含胶量一直平稳增长。分析不同发育时期果皮和叶片Eu HMGR基因表达量和含胶增长速率相关性发现,果皮Eu HMGR基因在不同发育时期的相对表达量和含胶增长速率呈显著正相关,而二者在叶片中无明显相关性。因此,推测Eu HMGR基因的表达与杜仲果皮中橡胶生物合成相关。     

水提取杜仲鲜皮活性成分工艺研究

以杜仲鲜皮作为原料,水为提取溶剂,采用单因素实验方法探讨料液比(1:5~1:60 g·mL~(-1))、提取时间(10~120 min)和提取温度(30~90℃)对杜仲皮总固形物得率及活性成分提取率的影响,并确定单因素实验最佳提取工艺为:料液比1:20,提取时间60 min,提取温度60℃。此条件下,总固形物得率为11.61%,其中活性成分绿原酸得率为0.073%,桃叶珊瑚苷得率为0.704%,京尼平苷得率为0.122%,松脂醇二葡萄糖苷得率为0.108%。水提取杜仲皮成分,方法简单,无环境污染和溶剂回收问题,本文为杜仲鲜皮活性成分提取和开发利用提供的实验依据。     

杜仲药用有效成分提取方法研究

为优选杜仲的提取工艺条件 ,本实验以杜仲提取液中氯原酸的含量和浸膏得率为指标 ,采用四因素三水平正交设计法 ,筛选影响杜仲提取工艺的因素 ,探索最优的提取工艺条件。实验证明合理的提取方法为 :12倍 6 0 %的乙醇回流 3次 ,每次 2小时 ;所得杜仲提取物中氯原酸含量为 8 72mg/g生药 ,浸膏得率为 2 0 6 8%。     

卵黄抗体的分离提取和纯化方法

卵黄抗体性能稳定,具有较强抵抗热酸、碱的能力,室温下可保持6个月的活性,4℃下放置几年活性不减,易于大规模生产等许多优点,卵黄免疫球蛋白的纯化方法 和哺乳动物的纯化方法 不同,包括有机物沉淀法,有机溶剂抽提法,天然胶法和水稀释法等粗提方法;凝胶过滤层析,离子交换层析和亲和层析等精细纯化方法。本文就卵黄抗体的分离和纯化方法的优缺点作一比较。     

Enhanced solvent extraction of polar lipids associated with rubber particles from Hevea brasiliensis

Biochemical studies of lipids bound to rubber particles have been complicated due to the solubility of polyisoprene chains in most extracting solvents and the rather delicate nature of polar lipids that are often denatured when traditional solvent extraction techniques are employed. In this paper, we describe a traditional technique and accompanying solvents that permit optimal extraction of rubber particle bound lipids. The technique, which is validated after characterizing the lipid extracts by elemental analysis, silica column adsorption and thin layer chromatography, appeared more suitable for extracting total lipids with optimal glycolipid and phospholipid contents. This technique is proposed as an alternative to traditional extraction methods used for solid natural rubber as it offers advantages with respect to ease of application, extract quality, extraction yields and reproducibility.     

Gas chromatography column as an ambient‐temperature volatile trap

Open‐tube volatile traps have largely been shunned in favor of solid adsorbent containing traps for the collection of volatile pheromones and attractants. Solid adsorbents require large solvent rinses and glass capillaries can be difficult to maneuver for the collection of volatiles from small or hard‐to‐reach odor sources. A gas chromatograph (GC) column (DB‐1), an open‐tube glass capillary, and a SuperQ^®‐containing capillary were compared for their collection efficiencies from rubber septa and live calling insects. All three traps captured similar ratios of test compounds from septa at airflows >10 ml per min. Eluting analytes from a packed adsorbent, SuperQ, required at least 30× more solvent than was required to collect all the pheromone from the open‐tube glass capillaries, and the GC column enjoyed an additional three‐fold reduced solvent volume compared to the glass capillary. Thus, analytes could be eluted from the GC‐column trap and directly analyzed on GC without solvent evaporation. We placed glass wool ‘plugs’ in both GC columns and glass capillaries and found no volatiles in these plugs, indicating that breakthrough did not occur during 1‐h collections at 25 ml per min. We demonstrate here that at ambient laboratory temperatures, a DB‐1 GC column effectively collects Oriental fruit moth sex pheromone volatiles from a rubber septum and live pheromone‐releasing moths. Release ratios of pheromone from rubber septa are consistent with earlier reports from static air systems, whereas the release ratio of the (Z)‐8‐dodecenyl alcohol (Z8‐12:OH) from female Grapholita molesta Busck (Lepidoptera: Tortricidae) differed from published results and is likely due to different collection methods or moth‐strain origin.     

The use of smoke acid as an alternative coagulating agent for natural rubber sheets' production

A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the rubber sheets obtained. This new method of rubber sheet preparation was introduced into Amazonian rainforest rubber tapper communities, which are actually producing in large scale. The physical-mechanical properties were similar among a large sheets made by different rubber tapper communities using this new method.     

Use of a Silicone Rubber (Clear Seal) as a Section Adhesive Resistant to Acid, Alkali and Heat

An optically clear silicone rubber adhesive is recommended for use in histochemical procedures in which detachment of tissue sections is likely. Procedure: Cut paraffin sections and float on a 45-50 C water bath; leave frozen sections on the microtome knife in the cryostat; spread the silicone rubber thinly and evenly over 2/3 of the slide (Clear Seal—General Electric, was used); pick up paraffin sections directly from the floatation water and frozen sections from the microtome knife with a warm slide; dry for 1.5 hr at 25 C; place paraffin sections in a 60 C oven for 0.5 hr, deparaffinize through xylene and hydrate through alcohols to water. Stain sections as desired, but avoid clearing agents before mounting after strong acid or alkaline treatment, and mount rapidly if a synthetic resin is used because of the solvent effect on the silicone rubber. Of the adhesives tried, silicone rubber is the only one capable of withstanding boiling 10% HCl for any period of time without detachment of sections.     

Rubber solvent: a clastogenic agent that fails to induce sister-chromatid exchanges.

Rubber solvent was tested for its ability to induce chromosome aberrations and sister-chromatid exchanges in human whole blood cultures. Following exposure to relatively low rubber solvent concentrations (0.0125% and greater) significant increases in the frequencies of chromatid gaps and breaks were observed. At higher rubber-solvent concentrations (0.05% and greater) there were also significant increases in the frequency of chromosome breaks. In contrast to the increase in chromosome aberrations following rubber-solvent exposure, rubber-solvent concentrations up to the toxic level failed to produce increases in the sister-chromatid exchange frequency.     

Crab shell chitin whisker reinforced natural rubber nanocomposites. 1. Processing and swelling behavior

Nanocomposite materials were obtained from a colloidal suspension of chitin whiskers as the reinforcing phase and latex of both unvulcanized and prevulcanized natural rubber as the matrix. The chitin whiskers, prepared by acid hydrolysis of chitin from crab shell, consisted of slender parallelepiped rods with an aspect ratio close to 16. After the two aqueous suspensions were mixed and strirred, solid composite films were obtained either by freeze-drying and hot-pressing or by casting and evaporating the preparations. The processing and swelling behavior of composite films were evaluated. It was concluded that the whiskers form a rigid network assumed to be governed by a percolation mechanism in the evaporated samples only. Comparatively, better resistance of evaporated samples than hot-pressed ones against swelling in an organic solvent medium is good evidence for the existence of a rigid chitin network. The values of diffusion coefficient, bound rubber content, and relative weight loss also supported the presence of a three-dimensional chitin network within the evaporated samples. The mechanical behavior of the composites gives additional insight and evidence for this fact (part 2).     

Negative Body Image Associated with Changes in the Visual Body Appearance Increases Pain Perception

Changing the visual body appearance by use of as virtual reality system, funny mirror, or binocular glasses has been reported to be helpful in rehabilitation of pain. However, there are interindividual differences in the analgesic effect of changing the visual body image. We hypothesized that a negative body image associated with changing the visual body appearance causes interindividual differences in the analgesic effect although the relationship between the visual body appearance and analgesic effect has not been clarified. We investigated whether a negative body image associated with changes in the visual body appearance increased pain. Twenty-five healthy individuals participated in this study. To evoke a negative body image, we applied the method of rubber hand illusion. We created an “injured rubber hand” to evoke unpleasantness associated with pain, a “hairy rubber hand” to evoke unpleasantness associated with embarrassment, and a “twisted rubber hand” to evoke unpleasantness associated with deviation from the concept of normality. We also created a “normal rubber hand” as a control. The pain threshold was measured while the participant observed the rubber hand using a device that measured pain caused by thermal stimuli. Body ownership experiences were elicited by observation of the injured rubber hand and hairy rubber hand as well as the normal rubber hand. Participants felt more unpleasantness by observing the injured rubber hand and hairy rubber hand than the normal rubber hand and twisted rubber hand (p<0.001). The pain threshold was lower under the injured rubber hand condition than with the other conditions (p<0.001). We conclude that a negative body appearance associated with pain can increase pain sensitivity.     

大针头垂直穿刺密封瓶时减少胶塞碎屑形成的方法

目的观察针尖斜面不同朝向垂直穿刺常用药物密封瓶胶塞碎屑的形成结果,以寻找减少胶塞碎屑形成的实用方法.方法取同一批号青霉素密封瓶592瓶,分别用左向法、右向法、上向法及下向法各穿刺148瓶次,观察各朝向穿刺胶塞碎屑的形成,将4种方法穿刺胶塞碎屑形成的结果构成比进行统计学处理.结果4种朝向穿刺胶塞以左向法穿刺胶塞碎屑形成率最低.结论相同条件下4种穿刺方法胶塞碎屑的形成机率以左向法最低,是一种安全、实用的方法.     

The use of soluble steroids within inflatable breast prostheses.

A cortisone derivative (Solumedrol, Upjohn) has been added to the saline used to fill inflatable breast prostheses. In the experimental laboratory this drug passed slowly through the silicone rubber bag into a surrounding solvent. Clinically, this use has been evaluated in 100 cases of augmentation mammaplasty, with no evidence of wound complications attributable to the steroid. The influence of significant capsule formation (or "hardness") was less than 5 percent in this series.