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21.
对口虾蛄小鄂腺的组成及各部分显微形态结构进行了研究。发现小颚腺由体腔囊、迷路和原肾管组成,无膀胱。体腔囊足细胞小,足状突起少;迷路细胞具有微绒毛且基底侧质膜内陷;原肾管细胞的微绒毛较短,数量少,但基底侧质膜内陷更深更宽。口虾蛄小颚腺相关的细胞结构虽较为原始,不很发达,但其基本生理能力应与日本沼虾的触角腺类似,即具排泄和渗透压调节功能。 相似文献
22.
Determination of chlorophenols in red wine using ionic liquid countercurrent chromatography as a new pretreatment method followed by high‐performance liquid chromatography 下载免费PDF全文
A countercurrent chromatography method for the enrichment and cleanup of chlorophenols from food samples was successfully established by using an ionic‐liquid‐modified two‐phase solvent system composed of dichloromethane containing 2% 1‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide and water. The column was firstly filled with the organic stationary phase, and then a large volume of sample was pumped into the column after it was equilibrated with pure water at the rotation speed. Finally, the trace amounts of chlorophenols extracted and enriched in the stationary phase were eluted out by an alkaline mobile phase and determined by high‐performance liquid chromatography. Under optimized conditions, the enrichment and cleanup of the chlorophenols can be fulfilled online with enrichment factors (34–65) and high recoveries (84.69–95.23%). The method has been applied to the determination of chlorophenols in real red wine samples with the limits of detection in the range of 1.89–4.21 μg/L. The present method is highly suitable for the pretreatment of large volume of aqueous sample for the determination of trace amounts of contaminants in food and environmental samples. 相似文献
23.
The self‐assembled (SA) molecular monolayers of a 3‐aminopropyltrimethoxysilane (3‐APTS) on a silicon (111) surface, and the effects of ultraviolet (UV) pre‐treatment for substrates on the assembling process have been studied using XPS and atomic force microscopy (AFM). The results show that the SA 3‐APTS molecules are bonded to the substrate surface in a nearly vertical orientation, with a thickness of the monolayer of about 0.8–1.5 nm. The SA molecular monolayers show a substantial degree of disorder in molecular packing, which are believed to result from the interactions of amine tails in the silane molecules used with surface functionalities of the substrates, and the oxygen‐containing species from the ambient. UV irradiation for silicon substrates prior to the self‐assembly reaction can enhance the assembly process and hence, significantly increase the coverage of the monolayer assembled for the substrates. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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利用模糊数学对学生物理实验进行综合评价 总被引:3,自引:2,他引:3
介绍了用模糊数学对学生物理实验进行综合评价的方法,避免了常规考试方法的许多弊端。 相似文献
26.
We synthesized Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu, the peptide contained in lactoferrin (Lf), to identify the angiotensin converting enzyme (ACE) inhibition. In an attempt to know the structure‐activity relationship of this peptide, we replaced Pro (the third amino acid residues from N‐terminal) or Val (the fourth amino acid residues from N‐terminal) with Ala (neutral amino acid), Glu (acidic amino acid) or Lys (basic amino acid) to produce six peptides. From the in vitro ACE inhibition (IC50) of these synthesized peptides, the original peptide (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu) showed higher ACE inhibition than the replaced six peptides. Thus, replacement of Pro at the third amino acid residues or Val at the fourth position with Ala, Glu or Lys revealed the ACE inhibition to be lower than the original form of Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu. Otherwise, we added one peptide at the C‐terminal of Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu and found both products with an addition of Val (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu‐Val) or Ile (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu‐Ile) showing a lower ACE inhibition than the original one. The ACE inhibitions produced by both replaced peptides were without significance. Also, deletion of the last peptide at the C‐terminal (Leu‐Arg‐Pro‐Val‐Ala‐Ala) failed to produce a marked change of ACE inhibition as compared to the original one. These results suggest that Pro and Val are essential in the peptide for inhibition of ACE activity. 相似文献
27.
本文对日本沼虾触角腺的形态学进行了初步研究 .日本沼虾的触角腺由体腔囊、迷路、原肾管和膀胱组成 .体腔囊细胞有许多足状突起 ,具有过滤功能 ;迷路占整个腺体的 4 / 5,其展开长度约 ( 10 0±10 ) cm;迷路细胞顶部具有发达的微绒毛、基部质膜内陷 .原肾管细胞的微绒毛短而不规则 ,基部质膜内陷却十分发达 ,原肾管的展开长度约 ( 4 0± 4 ) cm;膀胱细胞基部质膜也有内陷但无微绒毛 .上述结构是触角腺排泄功能和渗透压调节的重要基础 相似文献
28.
Nai Yun Ji Xiao Ming Li Lan Ping Ding Bin Gui Wang Institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate School of the Chinese Academy of Sciences Beijing China 《中国化学快报》2007,18(2):178-180
Two new aristolane sesquiterpenes, namely, aristolan-10-ol-9-one and aristolan-8-en-1-one, were isolated from the red alga Laurencia similis. Their structures were established on the basis of various NMR spectroscopic analyses, including 2D NMR techniques (1H-1H COSY, HMQC, HMBC, and NOESY) and HR-FAB-MS. 相似文献
29.
The crystal structure of 1,4,8,11,15,18,22,25‐octaethyloxyphthalocyaninatocopper was determined by X‐ray diffraction. The ring skeleton distortion is shown, which not only attributed to inter‐molecular steric congestion of substituents but also to the less overlap of the skeletons. 相似文献
30.