A convenient thin layer chromatographic method for the detection of cyclochlorotine and simatoxin,toxins fromPenicillium islandicum Sopp

Summary A rapid, convenient TLC method is described for detection of cyclochlorotine, a carcinogen produced by the commonly found storage moldPenicillium islandicum Sopp. This method has also led to the isolation of a new toxic metabolite, simatoxin.Acknowledgment. This work was supported by Food and Drug Administration, Washington, D.C. (Contract No. FDA-223-74-2209).     

An improved method for estimating the activity of a mouse with the photoswitch

A new method for estimating the activity of a mouse by means of the photoswitch is contrived. This device can follow the activity with high fidelity and notable sensitivity, as compared with the conventional method.     

基于均匀设计法的有限元网格划分与精度提高

本文首次运用均匀设计法的理论到有限元网格划分与精度提高领域,借助MATLAB程序计算,可以得出网格划分的关键点。运用二次开发的理念,在有限元网格划分时进行二次优化。具体思路是在求解同一个工程问题时,分别用均匀设计的方法计算得出结果（应力最优点）,再与有限元方法计算得出结果（应力梯度）比较,应力变化图如果吻合,可以在有限元划分网格时使用MATLAB优化的关键点来加密网格。因为结果相等说明均匀设计得到的优化点等价于变化梯度大的点,加密梯度变化大的点当然精度更高。后面的计算结果证明均匀设计法相对自适应网格划分时的优越性,为全部单元都加密时带来结果失真的问题提供了一种有效的解决方法。     

An improved method for estimating the activity of a mouse with the photoswitch

Summary A new method for estimating the activity of a mouse by means of the photoswitch is contrived. This device can follow the activity with high fidelity and notable sensitivity, as compared with the conventional method.     

Localization of sound producing animals using the arrival time differences of their signals at an array of microphones

Summary This method provides a reliable means to determine distance between vocalizing individuals and their locations through a prolonged period of time without disturbance to the communication process by the presence of an observer. The accuracy of this method was tested by varying the arrival time differences on the microphone grid for known locations in a random fashion. This test shows that a vocalizing animal within an area of 4 ha surrounding the microphone array can be localized with an accuracy of ±1 m. The accuracy decreases with the distance from the central area and as a function of the geometry of the array. The location of an individual can be determined based on 5 vocalizations given in sequence.Acknowledgment. This research was supported by funds granted to Irene Magyar from the Chapman Fund, The American Museum of Natural History and Sigma Xi, Grants in Aid of Research.     

A convenient thin layer chromatographic method for the detection of cyclochlorotine and simatoxin, toxins from Penicillium islandicum Sopp

A rapid, convenient TLC method is described for detection of cyclochlorotine, a carcinogen produced by the commonly found storage mold Penicillium islandicum Sopp. This method has also led to the isolation of a new toxic metabolite, simatoxin.     

悬索桥几何非线性及主缆受力分析

利用离散、节点平衡求解、系统平衡协调迭代的方法求得具有确定长度的缆索在荷载作用下的曲线形式,详细分析了缆索在荷载作用下的挠度及变形。然后将悬索桥分为两大子结构,即主缆柔性结构,及加劲梁、塔柱等劲性结构。在两大子结构间的耦合点建立平衡方程,进行直接迭代求解。文中并对目前较为常用的结构几何非线性求解法进行了深入的探讨。通过算例证明本文方法不仅计算简单,迭代自由度少,而且计算结果完全可以与精确解媲美,完全克服了非线性方程求解中解的飘移现象。     

A new approach to preparation and purification of colostrokinin from bovine colostrum

Summary A simple and rapid method is reported for preparation and partial purification of colostrokinin from bovine colostral whey. The active substance obtained at the described stage of purification appears to be a basic polypeptide of low molecular weight. This peptide proved to be undestroyed by pepsin, only partially by trypsin and completely by papain.Acknowledgment. This research was partially supported by the Italian Ministry of Health.     

Preparation of lymphocytes from small volumes of peripheral mouse blood

Summary A method was developed which allowed for the isolation of lymphocytes (95% of leukocytes in the final suspensions) from small volumes of peripheral mouse blood (38% recovery). The method proved of value for studies of murine lymphocytes which required biochemical analysis of samples from individual animals on a serial basis.This work was supported in part by a University College Faculty Research Grant.     

改进的等斜率灰色聚类法在地面水质量评价中的应用与分析

为了更好地将等斜率灰色聚类法应用于地表水质评价,提出了改进的等斜率灰色聚类法——灰色聚类样点排序法,并通过实例的计算比较,讨论灰色聚类样点排序法再权重处理过程的可行性。可以得出灰色聚类样点排序法能兼顾到：1）各测点地实测污染浓度都在级别标准范围内较有规律的变化,各污染物的标准之间差异不太大;2）污染物分布的离散度太大,各标准值之间差别也太大这两种情况。     

Le Dosage Spectrométrique du Mercure dans l'Air vers 1930

In the 1930s, atomic absorption spectroscopy replaced chemical methods for determining the amount of mercury in atmospheric air. The overall state of chemical analysis was favourable: physical instruments were moving into the chemical laboratory. This new method emerged from work in quantitative physics, and it met a need arising from the risk encountered by those who handled mercury. The new spectrometer, which originally functioned as a detector, also made precise and rapid quantitative determinations possible. This in turn encouraged industrialists to take out patents and make commercial use of the method after various improvements. This method is considered to be the ancestor of modern atomic absorption spectroscopy, which developed independently after 1960. The method developed in the 1930s could only be used for gaseous mercury, and it was not generalized as a method for quantifying other elements. The determination of mercury in air by atomic absorption spectroscopy was the first application of this technique; indeed, it was the only example of a specific use of atomic absorption. It was also part of the instrumental revolution.     

Purification of RNA from animal cells using diethyl-pyrocarbonate

Summary Extraction of RNA from animal cells by a method using diethyl-pyrocarbonate yielded 50–60% of the total RNA. RNA purified by a hot phenol-SDS method from adenovirus 2 infected cells showed about 9% homology with adenovirus DNA, and RNA purified by diethyl-pyrocarbonate-SDS showed over 7% hybridization. Profiles of RNA prepared by both methods were identical when studied by polyacrylamide gel electrophoresis.Acknowledgment. This investigation was supported by U.S. Public Health Services research grant No. 5R01-CA10724-03 from the National Cancer Institute.     

Rapid temperature programmed gas-liquid chromatography of volatile fatty acids (C1−C7) for the identification of anaerobic bacteria

Summary A gas liquid chromatography method for the separation of 10 volatile fatty acids (C₁–C₇ and isomers) has been improved by using oven temperature programmed conditions. In our conditions, the proprietary stationary phase SP 1220 introduced by Supelco Inc., gave sharp separation of volatile fatty acids in less than 8 min. This method was suitable for analyses with both thermal conductivity and flame ionization detectors.     

A new continuous optical assay for isocitrate lyase

Summary A new continuous optical assay method for isocitrate lyase is reported. This is a coupled assay which requires lactate dehydrogenase as an ancillary enzyme. The method yields linear data up to 0.12 units/ml. The assay is also suitable for crude extracts.Acknowledgment. This research was supported by grants of the Italian Ministero della Pubblica Istruzione.     

Underdetermination and decomposition in Kepler's Astronomia Nova

This paper examines the underdetermination between the Ptolemaic, Copernican, and the Tychonic theories of planetary motions and its attempted resolution by Kepler. I argue that past philosophical analyses of the problem of the planetary motions have not adequately grasped a method through which the underdetermination might have been resolved. This method involves a procedure of what I characterize as decomposition and identification. I show that this procedure is used by Kepler in the first half of the Astronomia Nova, where he ultimately claims to have refuted the Ptolemaic theory, thus partially overcoming the underdetermination. Finally, I compare this method with other views of scientific inference such as bootstrapping.     

Hydrogen production for ballooning during the French Revolution: An early example of chemical process development

When hydrogen-filled balloons were used for military purposes during the French Revolution, the method used to produce the hydrogen lifting gas was the passing of steam over incandescent iron. This paper describes the way this method was developed from the laboratory-scale experiments first performed by Lavoisier to regular field operation where balloons with a volume of 12,500 cubic feet were filled from specially designed reactors. The method was ultimately abandoned, but its development and demise provide a valuable case study of early science-based technology.     

Demonstration of cobalt in histological sections using ion microanalysis by high mass resolution : application to the study of experimental chronic epilepsy in the rat]

Cobalt is specifically detected in ion microanalysis by high mass resolution. This method allows detection of the remaining cobalt in histological sections of Rat's cortex, after treatment by topic application of cobalt powder and demonstrates a diffusion of the metal into the epileptic area.     

The accuracy of extrapolation methods; an automatic box–jenkins package sift

Hill and Woodworth (1980) proposed an algorithm suitable for identifying Box–Jenkins models automatically without reliance on the investigator. This paper first reviews the method. It is then used on the 111 series analysed by Anderson in the Makridakis forecasting competition. The results show that the automatic method of Hill and Woodworth is comparable in terms of accuracy to the full Box–Jenkins identification procedure.     

Tailored substrates for studies of attached cell culture

Substrates for studies of the interactions of attached cells with extracellular matrix components are often prepared by allowing a protein to adsorb from solution onto a glass or polystyrene substrate. This method is simple and effective for many studies, but it can fail in cases that require rigorous control over the structure and composition of adsorbed protein. Self-assembled monolayers formed by the spontaneous ordering of terminally functionalized alkanethiols onto a gold substrate are a class of well-ordered substrates and provide a convenient method for tailoring substrates with ligands, proteins and other groups. Methods that can pattern the monolayers provide a general strategy to create substrates that control the size, shape and spacing of attached cells. This review illustrates recent work that has used these methods of surface chemistry to create tailored substrates for studies in cell biology. Received 14 November 1997; received after revision 10 March 1998; accepted 10 March 1998     

Electrochemical synthesis of cysteinyldopas

Summary A fast and inexpensive method for the synthesis of mon- and dicysteinyldopas is described. Dopa is oxidized by electrochemical techniques, and cysteine is then added to give cysteinyldopas.Acknowledgment. This investigation has been supported by grants from the Swedish Cancer Society (project 626-B80-08XB and 626-B80-08P).