A model of nucleolar structure and behaviour

Zusammenfassung Ein mathematisches Modell wird beschrieben, wobei der Nukleolus als offenes System die fibrilläre RNS und die Ribonukleoproteingranula als Komplexstruktur aufgefasst werden. Die Formeln verwenden: Kerndurchmesser, Geschwindigkeit der Bildung von fibrillärer RNS, Moleküllänge, Halbwertszeit ihres Zerfalls sowie die Dichte der Ribonukleoproteingranula.     

甜橙油水乳系相转型温度(PIT)的研究

乳化体系的稳定性决定着乳系的货架寿命,用相转型温度(PIT)表征乳系的稳定性较为全面。本文以甜橙油—水体系为例,研究了乳化剂种类(吐温60、阿拉伯胶、低酯果胶)、浓度、水相pH值对于上述乳系PIT值的影响,分析了PIT值和贮存稳定性的关系。     

外推法消除实验系统误差的研究

对于某些实验，可用图像外推法消除系统误差。     

安络小皮伞(Marasmius androsaceus)Mun141菌株的选育

作者采用分离、纯化和诱变等方法，运用液体发酵，筛选出安络小皮伞（Ｍａｒｓｍｉｕｓａｎｄｒｏｓａｃｅｕｓ）Ｍｕｎ１４１高产菌株经３０ｔ发酵罐放大试验，结果显示，平均氯仿提取物含量为１２．３８％（标准差±４５．３８），较原菌株（ＭａＡ）提高５０．２４％，且性能稳定．同时，筛选出适宜Ｍｕｎ１４１生长的７＃固面培养基．Ｍｕｎ１４１菌株在７＃固体培养基上，菌丝萌发早，生长速度快，粗壮浓密，色泽纯正，其生长量高出原１＃固面培养基５－７％     

CsNiCl_3的热膨胀分析

本文使用哈密顿矩阵，计算出ＣｓＮｉＣｌ３的能级和ｇ因子随温度的变化，分析出Ｎｉ２＋－Ｃｌ－键长从５Ｋ～３００Ｋ的热膨胀，得到线性热膨胀为：δＲ＝Ｒ（３００Ｋ）－Ｒ（５Ｋ）＝２×１０－２和线性热膨胀系数：α＝１ＲｄＲｄＴ＝２．７３×１０－５Ｋ－１．     

一类两机器 no-wait 流水作业总完工时间问题

在两机器 no-wait 流水作业问题中,每个工件在加工前有一调整时间,加工完之后有一移走时间,同一工件的调整和移走是可以重叠的,但加工时间不能重叠,同时任一工件在第二台机器上的加工必须紧接在它在第一台机器上的加工之后进行,本文以总完工时间为目标函数,讨论问题最优解中工件排列应满足的条件;其次讨论当工件的三种时间满足一定条件时最优时间表的求法;最后为问题设计了一个近似算法.     

Dihydropyridine BAY-K-8644 activates chromaffin cell calcium channels

Douglas and Rubin suggested that "the role of acetylcholine as a transmitter at the adrenal medulla is to cause some brief change in medullary cells which allows Ca ions to penetrate them and trigger the catecholamine ejection process". The Ca2+-channel blocking agents, verapamil, nifedipine and nitrendipine, have been used widely to investigate the properties of slow Ca2+ channels in a variety of tissues, including the adrenomedullary chromaffin cell. Recently, small modifications to the nifedipine molecule produced a derivative, BAY-K-8644 (methyl-1,4-dihydro-2, 6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5-carboxylate), that in contrast to the Ca2+-channel blocking agents, stimulated cardiac and vascular smooth muscle contractility. We have tested whether this compound behaves as a Ca2+-channel activator at the chromaffin cell membrane as shown by Schramm et al. in smooth muscle cells. The experiments described here strongly suggest that it does so.     

The isolation and structure of 13,18-dehydroglaucarubinone,a new antineoplastic quassinoid fromSimarouba amara

Summary An investigation of the Guyana plantSimarouba amara Aubl. (Simaroubaceae) for antineoplastic quassinoids led to isolation and structural determination of the new quassinoids 2-acetylglaucarubine (1a) and 13,18-dehydroglaucarubinone (2). The previously known 2-acetylglaucarubinone (3a) and glaucarubinone (3b) were also obtained. The new quassinoid2 was found significantly to inhibit growth of the murine lymphocytic leukemia P388.Antineoplastic agents 59. For part 58 refer to M. T. Edgar, G.R. Pettit and T.H. Smith, J. org. Chem., in preparation.Acknowledgments. We wish to thank Mr B. Septe for providing the¹³C-NMR-data. Dr Jean H. Schmidt and Miss Linda M. Lange for assistance with biological studies.—G.R. Pettit is grateful to the National Cancer Institute (performed pursuant to contract No. N01-67048 with the Division of Cancer Treatment, NCI, National Institutes of Health, Dept. of Health, Education and Welfare), Public Health Services Research grant No. CA 16049-03 from the National Cancer Institute, the Fannie E. Rippel Foundation, Talley Industries, and the Phoenix Coca-Cola Bottling Co., for partial support of this investigation.