响应面法优化红花籽粕5-羟色胺衍生物提取工艺

利用单因素实验及响应面法优化红花籽粕5-羟色胺衍生物的提取工艺。通过单因素试验考察提取溶剂、原料粒度、提取时间、提取温度、液料比对红花籽粕5-羟色胺衍生物提取得率的影响,确定各因素的适宜水平。在此基础上,以5-羟色胺衍生物提取得率为响应值进行Box-Behnken中心组合试验设计,并建立二次回归方程,得到红花籽粕5-羟色胺衍生物的最佳提取工艺条件:提取溶剂为无水乙醇、原料粒度为32目、提取时间为2.4 h、提取温度为89℃、液料比为19∶1,此条件下,红花籽粕5-羟色胺衍生物的提取得率可达0.34%。     

盾叶薯蓣中薯蓣皂甙元提取新工艺的研究

为研究新工艺提取盾叶薯蓣薯蓣中薯蓣皂甙元的最佳实验指标,以薯蓣皂甙元得率为评价参数,采用6因素5水平的正交实验,用分光光度法对25种提取方法所得到的薯蓣皂甙元进行比较分析。结果表明,硫酸浓度对薯蓣皂甙元提取的影响最大,在实验室条件下,可采用20g样品加甲醇回流提取4h,回流速度为10min／次,用2．5mol／L的硫酸水解6h,120号溶剂汽油回流提取2h,回流速度为15min／次,能清洁快速提取盾叶薯蓣中的薯蓣皂甙元。     

动态连续逆流提取绞股蓝皂苷的研究

本文在中试条件下,通过单因素试验和正交试验考察不同因素对绞股蓝皂苷提取得率的影响,从而探讨动态连续逆流提取绞股蓝皂苷的最佳工艺。结果表明:动态连续逆流提取绞股蓝皂苷最佳条件为:提取溶剂温度为80℃,料液比为1∶35(g/mL),提取时间为50 min。在此条件下,绞股蓝提取物平均提取得率为33.95%,皂苷得率为8.9%;动态连续逆流提取绞股蓝皂苷具有生产连续性好、皂苷提取得率高、产品纯度高等优点。     

马齿苋多糖微波提取条件的优化

本文对微波辅助法提取马齿苋多糖的工艺进行了研究,分析了提取温度、提取时间、料液比对马齿苋多糖得率的影响,确定了微波辅助提取马齿苋多糖的最佳工艺条件为60℃,料液比1 g/30 mL,提取10min。在此条件下的多糖得率为13.87%。     

香樟果皮花色苷提取工艺优化及抗氧化研究

为了优化香樟果皮花色苷的最佳提取工艺条件,用乙醇作为提取溶剂,选取提取时间、提取温度、提取剂浓度、料液比、pH五因素,采用Box-Behnken建立三因素三水平模型,用响应面法优化各因素及其相互作用的最佳组合,用Design-Expert 8.0设计回归正交实验;同时用水杨酸比色法和DPPH法,测定了香樟果皮花色苷的抗氧化能力,并比较了不同放置时间对香樟果花色苷稳定性的影响。结果表明:香樟果花色苷最佳提取工艺的回归方程为Y=58.64+2.27A+12.78B+10.18C-14.01A2-11.00B2-7.56C2,R2=0.9796,模型拟合程度良好,在该试验范围内,模型能够准确反映花色苷的提取结果;最佳工艺参数分别为pH1.0、料液比1∶15、乙醇浓度78.59%、提取温度77.14℃、提取时间42.48min,在此条件下香樟果花色苷的得率为67.99mg·100g-1;在一定浓度范围内,香樟果皮花色苷清除羟自由基率和总抗氧化能力均与浓度成正线性相关,回归方程分别为y=0.3388x+13.485(R2=0.9856),y=0.0275x+0.0221,(R2=0.9966)。利用响应面法确定的最佳工艺条件合理,可用于香樟果皮花色苷的提取,同时香樟果花色苷具有良好的抗氧化活性,为天然色素的开发利用提供一定指导意义。     

红花桑寄生枝叶总黄酮提取工艺

以Al(NO3)3显色法于510nm测定红花桑寄生枝叶提取液的吸光度,聚酰胺提纯,以芦丁为标准计算含量,正交实验方法探讨以乙醇为溶剂提取该类化合物的最佳工艺条件,结果表明,桑寄生叶最佳提取条件是溶剂为70％乙醇、料液比1：35、80℃条件下提取3h;桑寄生枝的最佳提取条件是溶剂为50％乙醇、料液比1：15、80℃条件下提取3h,在对应条件下桑寄生总黄酮平均得率叶为9.47%,枝为5.25%。     

山葡萄籽中原花青素的提取

研究了提取溶剂、温度、时间、料液比4个因素对山葡萄籽中原花青素得率的影响.确定最佳提取工艺以70%丙酮为提取剂,在60℃条件下,提取120 min,料液比为17,原花青素的得率为2.31%     

正交设计优选贯叶连翘中总黄酮提取工艺

本文采用正交设计实验,对影响贯叶连翘总黄酮提取工艺的因素进行了系统考察。结果发现,以总黄酮得率作为考察指标,影响贯叶连翘总黄酮提取的主次因素为:溶媒种类>提取时间>提取次数>溶剂用量,其中溶媒种类、提取时间、提取次数均对总黄酮的提取有显著性影响;贯叶连翘中总黄酮的最佳提取工艺条件为:用10倍量80%乙醇提取3次,每次1h。建立了以UV法测定贯叶连翘中总黄酮的含量方法。     

山葡萄籽中原花青素的提取

研究了提取溶剂、温度、时间、料液比4个因素对山葡萄籽中原花青素得率的影响。确定最佳提取工艺：以70％丙酮为提取荆,在60℃条件下,提取120min,料液比为1：7,原花青素的得率为2．31％     

酶法提取银杏黄酮类化合物研究

本文研究了纤维素酶酶解法提取银杏总黄酮工艺。与传统的乙醇提取工艺相比,银杏总黄酮得率提高了18．92％。实验确定了最佳提取条件：酶浓度0．40mg／mL,酶作用时间120min,酶解温度50℃,酶解介质pH值为4．5,乙醇浓度70％,提取温度70℃。     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Feeding the vertebrate retina from the Cambrian to the Tertiary

The retina of the vertebrate eye is metabolically active and requires nutritive support. During the last 540 million years it has evolved into forms as complicated and nutritionally demanding as those found in avian or primate eyes. Diffusion from the choroid is generally able to supply the metabolic needs of thin retinae. However, when the thickness exceeds the limits of diffusion, structures are needed to supplement the vascular supply from the choroid. These supplemental nutritive devices include the choroidal gland, the falciform process and preretinal vascular plexus of fish, the conus papillaris of lizards, the pecten oculi of birds, the intraretinal vessels of mammals and a few novel systems that remain difficult to classify. These vascular systems are among the most variable features of the vertebrate eye. Here, we review classical and recent findings regarding such retinal nutrition systems, propose a three category classification for them based on histologic origins and speculate on the evolutionary forces which drove their development.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan