Uptake of aflatoxin B1 by plastic materials

Zusammenfassung Aflatoxin wird von einigen gebräuchlichen Kunststoffen innerhalb kurzer Zeit in verhältnismässig grosser Menge absorbiert. Die vorliegenden Ergebnisse erlauben es, analytische Fehler bei Verwendung ungeeigneten Materials zur Zirkulation oder Filtration von Aflatoxinlösungen zu vermeiden.

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This is contribution No. 660 of the Euratom Biology Division.     

无机功能晶体材料的结晶过程研究

功能晶体材料作为光、声、电等转换的重要介质,已经被广泛应用于能源、信息、航空航天等高新技术领域,是目前国际材料科学与工程学科发展的热点和前沿课题.结晶过程是制备功能材料的核心环节,结晶习性直接影响材料的光、电、磁、催化等功能特性.在无机材料的结晶过程中,晶体组成在微观上经历了从自由态离子到结晶态固体的相变过程.可以借助晶体组成离子的电负性及基团微观对称性的变化,研究结晶过程中聚集体的形成和结构演变规律.利用分子振动光谱能够从分子尺度上揭示非线性光学晶体材料在水溶液结晶过程中结晶学结构的形成过程,克服了传统原位观测手段中缺乏对非长程有序结构的确定.利用结晶生长的化学键合理论从热力学和动力学两个方面指导大块晶体的生长实践,合理调控晶体的生长表/界面热力学和动力学.将结晶生长的化学键合理论应用到大尺寸晶体提拉生长参数的设计和优化,成功搭建了大尺寸晶体智能生长系统,并成功生长了φ2″蓝宝石晶体、φ3″YAG晶体和φ4″铌酸锂晶体.     

Shifting ontologies, changing classifications: plant materials from 1700 to 1830

This paper studies European chemists’ shifting ontologies of materials by comparing the ways in which they classified materials. The focus is on plant materials, their different identities, and the changing ways chemists sorted out and ordered plant materials in the eighteenth and early nineteenth centuries. The main goals of the paper are to follow the development of plant materials from ordinary, everyday materials and commodities in the early eighteenth century to purified carbon compounds and organic substances familiar only to experts in the 1830s, and to reconstruct chemists’ ways of classifying these objects in different practical and intellectual contexts.The study of changes in European chemists’ ways of classifying plant materials over more than a century brings to the foreground a trajectory of ontological shifts that is ‘punctuated’ in the 1750s, the 1790s, and the 1830s. Early eighteenth-century plant materials, which were commodities of the apothecary trade and other arts and crafts, were elevated epistemically as compound components or ‘proximate principles’ of plants in the 1750s, reduced to organic compounds in the 1790s, and replaced by carbon compounds in the 1830s. The last, third transformation of the epistemic constitution of materials and the mode of their classification was accompanied by a deep transformation of the material culture of plant chemistry. After the late 1830s, many of the eighteenth-century vegetable commodities disappeared from chemists’ agenda or were split into different substances individuated and identified in new ways. Coal tar products, and new organic artefacts containing chlorine or bromine, entered the chemical laboratory in the 1820s and became fused with the purified rest of the previous plant and animal substances. The material objects of the new culture of organic chemistry became detached from the materials applied in the extant arts and crafts. It was only in the late 1850s, with the rise of the synthetic dye industry, that a great number of these laboratory substances became involved in industrial production.     

A cautionary note on pentacyanoammonioferrate use for determining L-canavanine occurrence in biological materials

Summary Caution must be taken in the prevelant use of the pentacyanoammonioferrate reagent for the detection of L-canavanine in biological materias. This reagent reacts with L-histidine at neutral pH to form a pentacyanoammonioferate-histidine complex that is mistaken readily for its canavanine-containing counterpart.This work was supported by a grant from the National Science Foundation (PCM-78-20167). This is publication number 81-7-199 of the Kentucky Agriculatural Experiment Station, Lexington     

Changes in the degree of orientation of bone materials with age in the human femur

Résumé On a étudié les photographies de diffraction des rayons X de 20 spécimens d'os fémoral d'individus âgés de 6 jours à 76 ans. On a pris des photographies des quadrants postérieurs et antérieurs. Les résultats indiquent que les crystaux d'apatite de l'os d'un enfant nouveau-né étaient orientés au hasard, à l'inverse de ceux d'un adulte.     

Changes in the histochemical nature of neurosecretory materials during axonal transport in the CrabParagrapsus gaimardii

Résumé Dans le système neurosécréteur du pédoncule oculaire et les organes péricardiques du crabeParagrapsus gaimardii, la direction du processus de modification du produit de neurosécrétion durant le cheminement axonal semble Être de sens opposé à celle qu'on observe chez les insectes et les grenouilles.     

Microbial influence on the sorption of137Cs onto materials relevant to the geological disposal of radioactive waste

Summary A major concern in the geological containment of radioactive wastes is the speed of movement of radionuclides from the repository, after their eventual leaching and release, into the geosphere and finally into the biosphere. Radionuclide sorption onto the host rock is an important retarding mechanism. Experimental evidence shows that the presence of microbes in this environment influences the sorption capabilities of the host rock. Their presence can decrease the amount of retardation of¹³⁷Cs, a common radionuclide in radioactive waste, by the solid phase. Sorption methods and data analysis procedures are presented and the implications for radioactive waste disposal assessments are discussed.     

The oral route for the bio-assay of aldosterone-like materials in the rat: Relative potency of aldosterone and chloro-cortisol

Résumé On démontre que chez le rat, l'administration orale de l'aldostérone et substances similaires pour essai biologique est pratiquable et sûre, bien que moins sensible que l'administration parentérale. Par inférence, il est suggéré que cette méthode est utilisable pour l'évaluation des antagonistes de l'aldostérone.A l'inverse de leur efficacité relative par voie parentérale, l'aldostérone est par voie orale moins actif chez le rat que l'acétate de 9-chlorocortisol pour produire l'abaissement du rapport Na⁺/K⁺.