绞股蓝总皂甙提取方法的比较研究

目的：探讨绞股蓝总皂甙最佳的提取方法。方法：首先选用水、80％甲醇、75％乙醇和氯仿等作为溶剂提取绞股蓝总皂甙,从中选择出2种较优试剂,再以回流提取法、索氏提取法、超声波法等提取方法对绞股蓝的总皂甙进行提取,从而选出一种优良的提取方法。并且采用分光光度法测定了绞股蓝总皂甙的含量。结果：研究表明,75％乙醇为绞股蓝总皂甙提取的最佳溶剂,乙醇回流提取法为最优方法。结论：以75％乙醇为提取溶剂的回流提取法是一种高效、简便、节能的绞股蓝总皂甙的提取方法。     

竹节参总皂苷不同提取工艺的比较研究

目的:通过比较竹节参总皂苷不同提取工艺以优选竹节参总皂苷稳定、可靠的提取工艺,以期为民族中药竹节参的现代化开发利用奠定实验基础.方法:以提取物中竹节参总皂苷含量和齐墩果酸含量以及提取物抗氧化能力作为考察指标,比较60％乙醇回流提取法、水提醇沉法、泡沫分离法、水饱和正丁醇超声提取法、60％乙醇超声提取法等提取工艺,希望为竹节参总皂苷提取工艺的选择提供参考.结果:60％乙醇超声提取法所得竹节参总皂苷提取率、齐墩果酸转移率相对较高,分别达到99.31％和33.59％,且提取物体外抗氧化活性相对较高达到71.30 U/g.结论:60％乙醇超声提取法具有提取时间短,稳定性好,有效成分转移率高,提取成本较低,可广泛应用于大型工业化生产等优点,为竹节参总皂苷的较优提取工艺.     

不同方法提取组培百里香精油质量及成分的比较分析

采用水蒸气蒸馏法、有机溶剂萃取法、CO2超临界萃取法3种提取方法提取组培百里香精油,比较分析精油得率、精油化学成分以及相对含量,以期得出最佳提取方法。结果表明：水蒸气蒸馏法提取的百里香精油得率为O．21％,主要化学成分为：百里酚（36．53％）、间伞花烃（14．13％）、松油烯（8．09％）和石竹烯（4．14％）;有机溶剂萃取法提取的精油得率为0．19％,主要化学成分为：1,2-苯二甲酸-单-2-乙基己基酯（55．23％）、百里酚（873％）、松油烯（5．23％）;CO2超临界萃取法提取的精油得率为0．27％,主要化学成分为：百里酚（26．68％）、3-苯基-2-丙烯酸-甲酯（21．55％）、间伞花烃（9．69％）。从精油得率、精油质量以及精油主要化学成分综合比较3种方法,水蒸气蒸馏法是提取百里香精油的最佳方法。     

负压空化法提取五倍子单宁酸的响应面法优化

本文将负压空化提取与响应曲面设计相结合的方法应用于五倍子单宁酸的提取中,利用中心组合(Box-Behnken)实验设计原理研究了提取温度、液固比、提取时间3个自变量对响应值单宁酸提取得率的影响.结果表明,负压法提取五倍子单宁的最佳工艺条件为:提取温度55℃、液固比24∶1 (mL∶g)、提取时间30 min,在此条件下单宁酸提取率为66.56％,与模型预测值(67.353％)相对误差为1.18％＜5％,证明响应面回归方程的预测值与试验值之间具有较高的拟合度.     

丹参提取工艺的实验研究

以丹参酮ⅡＡ、原儿茶醛为指标成分,采用正交试验法对丹参的提取工艺进行优选。结果表明,丹参的最优提取工艺为６倍量８０％酒精回流提取２次,每次２小时,再以６倍量６０％酒精回流提取１小时。     

绿豆皮中黄酮类化合物提取工艺

研究了绿豆总黄酮的提取工艺。通过对固液比、乙醇体积分数、提取温度与提取时间的单因素实验确定水平点,设计4因素3水平实验,选用L9（3^4）正交表,优选绿豆总黄酮的最佳提取工艺为固液比1：50,φ（乙醇）为40％,提取温度70℃,提取时间120min。在此基础上得到绿豆皮中总黄酮的提取量为27．57mg／g,且5次平行的相对标准偏差为0．75％,总黄酮的平均回收率达97．5％。     

水产废弃物胶原蛋白的提取

以水产废弃物为原料,利用酶法提取有价值的胶原蛋白。以胃蛋白酶为胶原蛋白提取用酶,鱼鳍和鱼鳞作为提取的原料,提取工艺为原料粉碎、脱钙、提取、纯化。鱼鳞和鱼鳍的胶原蛋白提取率分别达8．1％和6．6％。该方法对提高水产废弃物的综合利用具有重要的意义。     

麻栎叶黄酮的提取及其抗氧化活性研究

在单因素试验的基础上,对麻栎叶黄酮提取工艺进行优化,并研究了麻栎叶黄酮类化合物的抗氧化活性.结果显示,麻栎叶黄酮提取的最佳工艺是以60％乙醇为提取剂,提取物固液比1∶20,提取温度60℃,提取次数2次,微波功率640W、微波时间2 min,提取时间60 min,黄酮提取率为6.06 mg/g,回收率为96.5％.麻栎叶黄酮类化合物对自由基DPPH·、·OH以及亚硝酸盐的清除率分别达到97.7％、97.6％和94.4％.试验结果表明提取工艺合理,黄酮提取率高,麻栎叶黄酮提取液具有很好的抗氧化活性.     

千年桐种子油提取工艺研究及其主要脂肪酸成分分析

本文以氯仿、石油醚和正己烷-异丙醇(3:2,v/v)三种不同溶剂对千年桐种子油进行提取,比较了不同溶剂对种子出油率的影响,结果表明以氯仿为溶剂时出油率最高,达到了35％;并考查了提取时间和提取溶剂体积对出油率的影响.最终优化的提取工艺为:以氯仿为溶剂,液料比为12:1(v/w),提取时间6h,出油率达到了37％.提取的种子油经转酯化后,GC-MS分析其主要脂肪酸组分,结果表明千年桐种子油中总脂肪酸占总油酯的90.55％,其中棕榈酸3.87％,硬脂酸4.11％,亚油酸12.15％,油酸13.31％,亚麻酸12.09％,共轭亚麻酸51.20％和EPA(二十碳五烯酸)3.30％.千年桐种子油中富含不饱和脂肪酸,是一种良好的干性油.     

‘鸭梨’果心多酚氧化酶提取方法的优化

以‘鸭梨’为供试材料,通过设定不同实验条件,分析影响果心多酚氧化酶（polyphenoloxidase,PPO）提取效率的部分因素,以期找到提取‘鸭梨’果心多酚氧化酶的最适条件。结果表明：磷酸盐提取缓冲液的pH≥7．0,提取缓冲液中分别含有0．2％TritonX-100、1％SDS、6％-8％PVP、2％PVPP以及每克果心鲜样中加入2mg抗坏血酸时均能高效提取‘鸭梨’果心PP0。     

Effect of recombinant growth hormone on expression of growth hormone receptor, insulin-like growth factor mRNA and serum level of leptin in growing pigs

Growth hormone (GH) plays an important role in regulation of animal growth, metabolism and lactation[1]. Numerous studies have shown that exogenous somatotropin (ST) can increase average daily weight gain, improve feed efficiency, stimulate protein deposition and muscle growth and decrease lipid accretion rate[1]. The original somatomedin hypothesis suggested that the effect of GH on postnatal growth was mediated by insulin-like growth hormone factor 1 (IGF-I) which was thought to be deriv…     

Effect of recombinant growth hormone on expression of growth hormone receptor,insulin-like growth factor mRNA and serum level of leptin in growing pigs

Sixteen Large White × Landrace castrated male pigs were allotted into treatment and control group. The treatment group was injected intramuscularly with recombinant porcine growth hormone (rpGH, 4 mg d⁻¹) and the control group with vehicle for 28 days. Animals were slaughtered 4 h after final injection for liver, longissimus dorsi (LD) muscle and blood sampling. Serum concentration of insulin-like growth factor 1 (IGF-I) and leptin were determined by RIA. The total RNA was extracted from tissues to measure the abundance of growth hormone receptor (GHR), IGF-I mRNA by RT-PCR with 18S rRNA internal standard. Results showed that rpGH enhanced the average daily weight gain by 26.1% (P < 0.05), the serum IGF-I concentration by 70.94% (P < 0.01), decreased serum leptin by 34.8% (P < 0.01). The relative abundance of GHR and IGF-I mRNA in liver were increased by 24.45% (P < 0.05) and 45.30% (P < 0.01), respectively, but no difference of GHR (P > 0.05) and IGF-I mRNA (P > 0.05) in LD between GH treated and control group was found. These results suggest that rpGH can up-regulate hepatic GHR and IGF-I gene expression and improve animal growth. However the effect of rpGH on GHR and IGF-I gene expression are tissue-specific.     

两种不同方法制备的黑木耳多糖性质比较

本研究以黑木耳子实体为材料,对比了壳聚糖絮凝法制备的絮凝多糖HJD-1和传统水提醇沉法制备的醇沉多糖HJD-2的表观结构、α-葡萄糖甘酶抑制活性以及体外抑制肿瘤细胞增殖的活性。结果表明：（1）壳聚糖絮凝法制备粗多糖得率均值为4.76%,是醇沉法的2.17倍;醇沉法制备多糖的损失率为33.87%,是絮凝法的1.36倍;（2）絮凝多糖HJD-1和醇沉多糖HJD-2的表观评估及复溶性结果分析显示：絮凝多糖HJD-1为亮白色透明晶体,色泽均匀,颗粒规整;醇沉多糖HJD-2为棕褐色,颗粒状,有砂质感,前者相较后者的复溶性更好;（3）对α-葡萄糖甘酶抑制活性以及体外抗肿瘤能力结果分析表明：在相同浓度下,壳聚糖絮凝法制备黑木耳多糖对α-葡萄糖苷酶活性的抑制效果优于醇提法;絮凝多糖HJD-1对HepG2细胞的增殖抑制作用强于醇沉多糖HJD-2。     

A method for the fractionation of the high-mobility-group non-histone chromosomal proteins

A method is given for the preparation of four non-histone chromosomal proteins, one of which, protein 14, hitherto has not been isolated. The method also enables the preparation of histone H1 in gram quantities. The four non-histone chromosomal proteins so prepared are all polar molecules over 50% of each being composed of acidic and basic amino acids. It is also shown that protein 14 can be prepared from calf thymus without prior isolation of chromatin.     

Optimized recirculation survival of mouse carrier erythrocytes.

Carrier mouse erythrocytes prepared by a hypotonic dialysis technique and reinjected into mice have a 24 hour survival of approximately 50%. Twenty-four hour survival can be improved substantially to 74% by removing the more fragile erythrocytes by a hypotonic wash treatment. The mean cell volume of the carriers prepared by this modification is significantly (p less than 0.01) different from cells prepared by the standard method with a isotonic wash treatment. Carriers prepared by the hypotonic treatment wash modification exhibit a different 50% hemolytic value (15% difference) from isotonically prepared carriers, and normal erythrocytes. Carrier-erythrocytes removed from mice 24 hour post-injection exhibit an osmotic profile that is independent of the treatment. Carriers were also prepared by another modification of the encapsulation procedure and held in a permeable state overnight before resealing and annealing. Carriers prepared in this manner showed a much lower 24 hour survival (13%).     

Autoradiographic Differentiation of Free, Bound, Pure, and Impure Thymidine-3H

Intestinal tissue from animals injected with tritium-labeled thymidine were examined by two autoradiographic methods. Conventional autoradiograms using fixed, solvent-dehydrated, paraffin-embedded tissues, and wet mounted, were compared with an autoradiographic method designed for localizing diffusible substances utilizing dry-mounted, freeze-dried frozen sections. The autoradiograms prepared by conventional methods show more than 95% of the activity located over the nucleus while, autoradiograms of intestinal tissue from the same animal prepared by the freeze-dried method shows only 88% of the activity over the nucleus. Animals injected with impure thymidine-³H, containing self-radiolysis decomposition products due to storage, led to significant alteration in the autoradiographic pattern, particularly those prepared by the freeze-dried method which show only 52% of the activity over the nucleus. Thus, conventional treatment of tissue extracted free unincorporated thymidine, metabolic products of thymidine-³H, and impurities of thymidine-³H. However, autoradiograms prepared by the dry-mounted freeze-dried method retained all the label.     

Stable isotope dilution high-performance liquid chromatography-electrospray ionization mass spectrometry method for endogenous 2- and 4-hydroxyestrones in human urine

A sensitive, precise and accurate stable isotope dilution high-performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for measuring endogenous 2- and 4-hydroxyestrones, the main catechol estrogens in human urine. Compared to the published methods using gas chromatography-mass spectrometry, this approach simplifies sample preparation and increases the throughput of analysis. The unique part of our method is the use of a simple and rapid derivatization step that forms a hydrazone at the C-17 carbonyl group of catechol estrogens. This derivatization step has greatly enhanced method sensitivity as well as HPLC separability of 2- and 4-hydroxyestrones. Standard curves were linear over a 100-fold calibration range with correlation coefficients for the linear regression curves typically greater than 0.996. The lower limit of quantitation for each catechol estrogen is 1 ng per 10-ml urine sample, with an accuracy of 97-99% and overall precision, including the hydrolysis, extraction and derivatization steps, of 1-3% for samples prepared concurrently and 2-11% for samples prepared in several batches. This method is adequate for measuring the low endogenous levels of catechol estrogens in urine from postmenopausal women.     

A rapid centrifugation method for the isolation of polymorphonuclear leucocytes from human blood

A rapid one-step gradient centrifugation method to prepare PMN leucocytes has been worked out by which a 98--99% pure, washed granulocyte suspension of 98% viability can be obtained in 30--40 minutes. The cells prepared by this method displayed higher NBT reduction upon ingesting the same soluble DNA-anti DNA complexes than those prepared by the dextran sedimentation method.     

Metal‐Oxide‐Free Methylammonium Lead Iodide Perovskite‐Based Solar Cells: the Influence of Organic Charge Transport Layers

Metal‐oxide‐free methylammonium lead iodide perovskite‐based solar cells are prepared using a dual‐source thermal evaporation method. This method leads to high quality reproducible films with large crystal domain sizes allowing for an in depth study of the effect of perovskite film thickness and the nature of the electron and hole blocking layers on the device performance. The power conversion efficiency increases from 4.7% for a device with only an organic electron blocking layer to almost 15% when an organic hole blocking layer is also employed. In addition to the in depth study on small area cells, larger area cells (approx. 1 cm^?2) are prepared and exhibit efficiencies in excess of 10%.