A Microtube Viscometer with a Thermostat

The viscometer presented in this paper is suit-able for measuring the viscosity of liquids in micro-litre quantities. It consists of a micro-flow experimental system with a thermostat. Using the measurements of the flow rates and pressure drops of a liquid passing through a microtube, the liquid's viscosity can be calculated from on Hagen-Poiseuille theory. After calibration, the viscometer was used to measure viscosities of deionized water and ethyl alcohol at temperatures ranging from 0 to 40 "C. For both test liquids, the relative deviation of the measured values from those quoted in the literature (obtained using other viscometers) was less than 2.6o/o. The relative uncertainty of the experimental system was reduced to +-l.8% using the relative measuring method. Due to the micro-scale of the test section, only a micro-litre quantity of liquid is needed for a test, this is a potential advantage for measurement of bio-liquid viscosities.

Study on polymer micelles of hydrophobically modified ethyl hydroxyethyl cellulose using single-molecule force spectroscopy

Individual hydrophobically modified ethyl hydroxyethyl cellulose (HM-EHEC) molecules under different conditions were elongated using a new atomic force microscope (AFM) based technique-single-molecule force spectroscopy (SMFS). The critical concentration of HM-EHEC for micelle-like clusters at a solid/liquid interface was around 0.8 wt %, which is lower than that in solution. The different mechanical properties of HM-EHEC below and above the critical concentration were displayed on force-extension curves. Through a comparison with unmodified hydroxyethyl cellulose, substituent-induced effects on nanomechanical features of HM-EHEC were investigated. Because of hydrophobic interactions and cooperative binding with the polymer, surfactants such as sodium dodecyl sulfate (SDS) dramatically influence the elastic properties of HM-EHEC below the critical concentration, and further addition of SDS reduces the interactions between the hydrophobic groups and the surfactant.

Study of the effect of alcohol on single human red blood cells using near-infrared laser tweezers Raman spectroscopy

The effect of alcohol solution on single human red blood Cells (RBCs) was investigated using near-infrared laser tweezers Raman spectroscopy (LTRS). In our system, a low-power diode laser at 785 nm was applied for the trapping of a living cell and the excitation of its Raman spectrum. Such a design could simultaneously reduce the photo-damage to the cell and suppress the interference from the fluorescence on the Raman signal. The denaturation process of single RBCs in 20% alcohol solution was investigated by detecting the time evolution of the Raman spectra at the single-cell level. The vitality of RBCs was characterized by the Raman band at 752 cm(-1), which corresponds to the porphyrin breathing mode. We found that the intensity of this band decreased by 34.1% over a period of 25 min after the administration of alcohol. In a further study of the dependence of denaturation on alcohol concentration, we discovered that the decrease in the intensity of the 752 cm(-1) band became more rapid and more prominent as the alcohol concentration increased. The present LTRS technique may have several potential applications in cell biology and medicine, including probing dynamic cellular processes at the single cell level and diagnosing cell disorders in real time. Copyright (c) 2005 John Wiley T Sons, Ltd.

4-Benzyl-5-ethyl-2-(2-furylcarbonylmethylsulfanyl) pyrimidin-6(1H)-one

The title compound, C19H18N2O3S, shows favourable activity against HIV-1. The phenyl ring is twisted with respect to the pyrimidine ring by 61.56 (9)degrees. Intermolecular N-H center dot center dot center dot O and C-H center dot center dot center dot O

Waterborne exposure to fluorotelomer alcohol 6:2 FTOH alters plasma sex hormone and gene transcription in the hypothalamic-pituitary-gonadal (HPG) axis of zebrafish

Fluorotelomer alcohols (FTOHs) have shown estrogenic activity in vitro and in vivo, but the mechanism of this activity is not known. In this study, 18-week-old zebrafish (Danio rerio) were exposed to 0, 0.03, 0.3 and 3.0 mg/l 1H, 1H, 2H, 2H-perfluorooctan-1-ol (6:2 ETCH) for 7 days, and the effects on plasma sex hormone levels were measured followed by use of real-time PCR to examine selected gene expression in hypothalamic-pituitary-gonadal (HPG) axis and liver. Exposure to 6:2 FTOH significantly increased plasma estradiol (E2) and testosterone (T) levels in both males and females. Furthermore, the ratio of T/E2 was reduced in females while increased in males. In females, the increase of E2 was accompanied by up-regulated hepatic estrogenic receptor alpha (ER alpha) and vitellogenin (VTG1 and VTG3) expression. In males, the elevation of the T level is consistent with the up-regulation of cytochrome P450 c17 alpha-hydroxylase, 17, 20-lase (CYP17) and the down-regulation of cytochrome P450 aromatase A (CYP19A). The present study demonstrated that waterborne exposure to 6:2 FTOH alter plasma sex hormone levels and the ratio of T/E2, as well as the transcriptional profiles of some genes in the HPG axis and liver. The results suggested that FTOHs may disturb fish reproduction through endocrine disrupted activity. (C) 2009 Elsevier B.V. All rights reserved.

手性有机小分子路易斯碱催化剂的设计、合成及其在亚胺不对称还原中的应用

手性胺是合成天然产物和手性药物的重要中间体，亚胺的不对称催化还原是制备光学活性手性胺的最直接有效的方法之一。但是，由于C＝N双键的反应活性较弱以及容易发生E/Z异构等问题，亚胺的不对称催化还原具有很大的挑战性，既具有高对映选择性又具有宽广底物普适性的催化剂很少。 本文分别由手性脯氨酸、哌啶酸、哌嗪酸以及氨基醇出发，设计和合成了一系列结构新颖、合成简便、性能优良的酰胺类有机小分子路易斯碱催化剂，以廉价的三氯氢硅为氢源，用这些催化剂催化亚胺不对称还原，得到了非常优良的收率、对映选择性和前所未有的底物普适性。 文献研究认为，除N-甲酰基外，分子内含有芳香酰胺是能催化亚胺还原的有机小分子路易斯碱催化剂具有较高对映选择性的必要条件，我们研究发现N-甲酰脯氨酸非芳香酰胺类催化剂（包括结构简单的C2-对称型脯氨酰胺类催化剂），对N-芳基酮亚胺的还原可获得达86%的对映选择性，远高于同类芳香酰胺催化剂，证明N-甲酰非芳香酰胺类路易斯碱催化剂在亚胺还原中也能得到高的对映选择性。 在进一步研究中，我们以手性六元哌啶酸为模板，分别设计合成了N-甲酰哌啶酸芳香酰胺和N-甲酰哌啶酸非芳香酰胺两类催化剂，其中芳香酰胺催化剂（S）-N-（甲酰基）哌啶-2-酸-1-萘基酰胺（28）和非芳香酰胺催化剂（2S,1'S,2'S）-N-（甲酰基）-哌啶-2-酸（1',2'-二苯基-2'-乙酰氧基-乙基）酰胺（30）显示出非常优良的催化活性和对映选择性，对于N-芳基芳香酮亚胺的还原，无论是缺电子体系还是富电子体系，绝大部分都能得到很高的收率（达98%）和对映选择性（达96% ee)。特别值得一提的是30对一些脂肪族亚胺和α,β-不饱和亚胺的还原，虽然底物为E/Z混合物，也能得到很高的收率（达93%）和对映选择性（达95% ee)，这样的底物普适性在过渡金属催化体系中也是前所未有的。 现有的催化亚胺还原的高对映选择性催化体系大多仅适用于甲基酮亚胺底物，对位阻较大的非甲基酮亚胺很难获得好的结果。我们以L-哌嗪酸为模板设计和合成出的（S）-N-（甲酰基）-哌嗪-2-酸-4-对叔丁基苯磺酰基-苯基酰胺不但对N-芳基甲基酮亚胺有很好的对映选择性（达90% ee)，而且对于大位阻的N-芳基非甲基酮亚胺有更好的对映选择性（达97% ee)。该催化剂与30在底物普适性方面具有很好的互补性。 我们还设计了基于1,2-二苯基氨基醇为模板的新型N-甲酰路易斯碱有机小分子催化剂，首次发现结构简单的N-甲酰（1S,2R）二苯基氨基醇能较好的催化N-芳基酮亚胺，最高可以得到82%的对映选择性。 针对我们设计合成的结构新颖、性能优良的催化剂，我们对催化机理进行了探讨和解释，提出了几个假想的机理模型。 Catalytic enantioselective reduction of imines represents one of the most straightforward and efficient methods for the preparation of chiral amines, an important intermediate for the synthesis of natural products and chiral drugs. However, asymmetric reduction of imines remains a big challenge and highly enantioselective catalysts with a satisfactorily broad substrate scope remain elusive. Factors contributing to the difficulty of this transformation include the weak reactivity of the C=N bond and the existence of inseparable mixtures of E/Z isomers. Starting from chiral proline, pipecolinic acid, piperazine-2-carboxylic acid and 1,2-diphenyl amino alcohol, a series of structurally simple and easily prepared amides were developed as highly effective Lewis basic organocatalysts for the asymmetric reduction of imines with trichlorosilane as the reducing agent, which promoted the reduction of N-aryl imines with high yields and excellent enantioselectivities with an unprecedented substrate spectrum. In the literature, it has been believed that besides the N-formyl group, the existence of an arylamido group in the structure of Lewis basic organocatalysts is a prerequisite for obtaining high enantioselectivity in the catalytic reduction of imines. However, we found that the N-formyl-L-prolinamides bearing non-arylamido groups, including structurally simple C2-symmetric tetraamides, could also work as effective Lewis basic catalysts to promote the asymmetric reduction of ketimines with high enantioselectivities (up to 86% ee), which are even more enantioselective than the analogues with arylamido groups. In further studies, we developed novel N-formamides with arylamido groups and non-arylmido groups as Lewis basic catalysts using the commercially available L-pipecolinic acid as the template. The catalysts (S)-1-formyl-piperidine-2-carboxylic acid naphthylamide 28 and (2S,1'S,2'S)-acetic acid 2-[(1-formyl-piperidine-2-carbonyl) -amino]-1,2-diphenyl-ethyl ester 30 were found to promote the reduction of a broad range of N-aryl imines in high yields (up to 98%) and excellent ee values (up to 96%) under mild conditions. Furthermore, catalyst 30 also exhibited high enantioselectivities (up to 95% ee) for the challenging aliphatic ketimines and α,β-unsaturated imines despite that these imines exist as E/Z isomeric mixtures. The broad substrate spectrum of this catalyst is unprecedented in catalytic asymmetric imine reduction, including transition-metal-catalyzed hydrogenation processes. Many of the currently available highly enantioselective catalytic systems only tolerate methyl ketimines, which gave poor results for bulkier non-methyl ketimines. Starting from L-piperazine-2-carboxylic acid, we developed (S)-4-(4-tert- butylbenzenesulfonyl)-1-formyl-N-phenyl-piperazine-2-carboxamide as highly enantioselective Lewis basic catalysts for the hydrosilylation of both methyl ketimines and steric bulky non-methyl ketimines. Moreover, higher enantioselectivities were obtained for non-methyl ketimines than methyl ketimines under the catalysis of this catalyst. Thus, this catalyst system complements with 30 in terms of the substrate scope. We also found that easily accessible (1R,2S)-N-formyl-1,2-diphenyl- 2-aminoethanol worked as an effective Lewis basic catalyst in the enantioselective hydrosilylation of ketimines, affording high enantioselectivities (up to 82% ee) for a broad range of ketimines. To rationalize the high efficiencies of the structurally novel catalysts we developed, several catalytic models have been proposed.

一株放线菌发酵产物抗肿瘤活性的研究

本学位论文主要研究一株放线菌发酵产物的抗肿瘤活性。先对该株放线菌进行活化培养，然后进行大批量发酵，发酵液经过冷冻离心，对离心得到的沉淀和上清液用不同极性的有机溶剂进行萃取，得到六个浸膏样品。对六个样品进行初步抗肿瘤活性检测。 然后对活性浸膏进行分离纯化和活性跟踪。本论文主要进行了如下的工作： 1、对菌种进行活化培养，利用该菌株在280C，200r.min-1条件下进行发酵实验，发酵时间为72h,发酵总量为15L。发酵液经过离心得到上清液和沉淀两部分。 2、分别用石油醚、乙酸乙酯、正丁醇萃取沉淀和上清液，得到编号为1—6的六个浸膏样品，对六个浸膏样品进行初步的细胞毒性和抗HepG2肿瘤活性实验，得出结论为5号样品活性最高。在没有分离纯化的情况下GI50达到0.76µg/mL。 3、对5号样品进行TLC实验，找出能够较好分离5号样品中各组分的溶剂组合，最后得出在氯仿：甲醇=8：1时分离效果较好。然后利用氯仿：甲醇=8：1的溶剂组合作为洗脱剂对5号样品进行过硅胶柱分离纯化并进行活性跟踪分离。 4、对分离纯化后得到的样品进行活性跟踪和结构分析。分离后得到样品A，在其浓度为10µg/ml时，抗肿瘤实验细胞的生长率为73.5%。在浓度为1.0mg/ml时，抗单纯疱疹病毒率（HSVⅡ）为74.5%。结构分析得知其分子式最可能为C41H43N8O4. This dissertation studied about the anti-tumor activity of an actinomycete fermentation product. First, we cultured the actinomycete. Second, we fermented it in large quantities, and then centrifuged the fermentation fluid; the next step is that we extract sedimentation and supernatant in different polar organic solvents, in turn to obtained six samples, which were detected about anti-tumor activity. Last, we purified active sample and tracked activity of it. We carried out the following research work: 1. Activation, culture and screening of the actinomyces was carried on. We used the screening strain to carry on the fermentation when the conditions are 280C，200r.min-1,the fermentation time is 72h. Fermentation fluid volume is 15L.And we obtained sedimentation and supernatant after fermentation fluid was centrifuged. 2. We used Petroleum ether, ethyl acetate, n-butanol separately to extract sedimentation and supernatant, and obtained six samples that were numbered 1-6. From the preliminary cell toxicity and the anti-tumor（HepG2） bioactivity experiment, we found that No.5 sample has the highest activity in the samples; the GI50 was 0.76µg/ml which has not been purified. 3. We Carried on TLC experiment on the No.5 sample, found the solvent composition that can separate each component of the No.5 sample. At last, we found that when the proportions are tri-chloromethane: methyl alcohol = 8:1, the Separation result was the best, and then we used the Solvent composition which proportion are tri-chloromethane: methyl alcohol = 8:1 as eluant to Purify No.5 sample by silica gel column. 4. We tracked the activity of pure sample obtained from Purification and analyzed structure of these substances. We got a compound A after separation, and the cell growth rate was 73.5% when its concentration was 10µg/ml. The anti-virus（HSVⅡ） rate was 74.5% when its concentration was 1.0mg/ml. We analyzed the Structure of A, and informed its molecular formula that was the most likely for C41H43N8O4.