Simple theoretical criterion of chemical carcinogenicity—a refutation

Summary The quasi-valence number criterion for chemical carcinogenicity has been shown, through several examples, to be untenable.     

Simple theoretical criterion of chemical carcinogenicity - a refutation.

The quasi-valence number criterion for chemical carcinogenicity has been shown, through several examples, to be untenable.     

A simple theoretical criterion of chemical carcinogenicity?

The simple theoretical criterion for chemical carcinogenicity based on the 'average quasi-valence number' is discussed and shown to be inappropriate as a reliable indicator of carcinogenicity of any organic compound.     

Theoretical prediction of carcinogenicity: quasi-quantification by quasi-valence.

We have shown the recently proposed method for prediction of carcinogenicity by "average quasi-valence number" to be neither a good predictor of carcinogenicity, nor of non-carcinogenicity.     

Correlation between the carcinogenicity of organic substances and their spectral characteristics

Summary A correlation between the carcinogenicity of organic substances and their UV-absorption characteristics has been established. It is found that chemical carcinogens have absorption maxima in the wavelength region of 206–248 nm. On the basis of revealed correlation, a mechanism of chemical carcinogenesis is proposed.     

Relation between carcinogenicity and metabolic reduction of 4-nitroquinoline 1-oxide derivatives

Zusammenfassung Untersuchungen über eventuelle Zusammenhänge zwischen der Karzinogenität gewisser Nitrochinolinderivate und deren Fähigkeit, enzymatisch zu Hydroxylaminverbindungen reduziert zu werden.     

Model systems demonstrating the volatile mutagenicity and carcinogenicity of sodium nitrite in rats

Volatile mutagens derived from sodium nitrite buffered at various pH values or in the presence of human feces were detected using Ames Salmonella tester strain TA 1535 on petrie plates inverted over samples. Volatile mutagenicity increased as the pH decreased and was primarily a function of the nitrous acid produced from sodium nitrite and hydrogen ions. Sodium nitrite administered intracecally to 3 Wistar rats through surgically implanted cannula caused tumors (fibrosarcoma: 1/3 and squamous cell, 2/3). The possible role of nitrite-derived mutagens in GI cancer is discussed.     

Model systems demonstrating the volatile mutagenicity and carcinogenicity of sodium nitrite in rats

Summary Volatile mutagens derived from sodium nitrite buffered at various pH values or in the presence of human feces were detected using AmesSalmonella tester strain TA 1535 on petrie plates inverted over samples. Volatile mutagenicity increased as the pH decreased and was primarily a function of the nitrous acid produced from sodium nitrite and hydrogen ions. Sodium nitrite administered intracecally to 3 Wistar rats through surgically implanted cannula caused tumors (fibrosarcoma: 1/3 and squamous cell, 2/3). The possible role of nitrite-derived mutagens in GI cancer is discussed.The authors are grateful to Dr A. Carl MacDonald of the Dept. of Surgery, Dalhousie University for his advice and encouragement in this project.This work was supported by the National Cancer Institute of Canada.     

Information as a quantitative criterion of biospheric evolution

Zusammenfassung Theodoridis undStark ¹ haben vorgeschlagen, dass der Informationsinhalt der Biosphäre ein objektives Kriterium des Evolutionsfortschritts schafft. In dieser Aufzeichnung prüfe ich diesen Informationsbegriff nach und schliesse daraus: 1. dass ein zuständiges Mass noch nicht vorhanden ist; 2. dass die Informationsbeweise in der genetischen Evolution irreführend sein mögen; und 3. dass wir vorerst die folgenden Parameter zu bestimmen und zu messen versuchen sollten: die Gesamtinformationen der Biosphär; die mindeste Obergrenze der Eingangsinformationen, die für jede besondere Lage der Biosphäre unentbehrlich ist; und die überholte Informationenmenge in dem Genom der einzelnen verschiedenen Spezies.     

On the association between lysogeny and carcinogenicity in nitroquinolines and related compounds

Zusammenfassung In einer Serie von 16 Nitroquinolinen und verwandten Substanzen wurde eine gute Übereinstimmung zwischen Phageninduktion inEscherichia coli C-600 und Karzinogenese nachgewiesen.

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Supported by grants No. C-6516 and FR-05526 from the National Cancer Institute and Contract NO. PH 86-66-169 from the Division of Air Pollution, U.S.P.H.S. We thank Dr.Y. Kawazoe of the National Cancer Center Research Institute, Tokyo, for his generous gift of the compounds tested.     

混凝土材料非线性多轴动态强度准则

将广义非线性强度理论的4个材料参数转化为混凝土材料的基本强度参数,通过混凝土材料的基本强度特性,分析了4个材料参数的变化规律与取值范围.基于S准则建立了混凝土材料4个基本强度参数的率效应表达式,建立了混凝土材料的非线性多轴动态强度准则,分析了动态强度参数的率效应规律,结果表明,混凝土材料的强度特性随着应变率的提高,逐渐向金属材料的强度特性过渡,在应变率从-3~3,应变率对混凝土动态强度的影响较大,并且动强度不是随着应变率的提高无限增大的,而是存在动强度峰值.通过与3组双轴压-压和2组双轴拉-压动态加载时混凝土材料试验结果的比较,表明非线性多轴动态强度准则可较好地描述混凝土材料双轴动强度规律.在同一应变率下,可较好地描述强度的非线性特性;不同应变率下,动强度面互不相交,即应变率效应与多轴应力状态对强度规律不存在耦合影响.     

A choice-semantical approach to theoretical truth

A central topic in the logic of science concerns the proper semantic analysis of theoretical sentences, that is sentences containing theoretical terms. In this paper, we present a novel choice-semantical account of theoretical truth based on the epsilon-term definition of theoretical terms. Specifically, we develop two ways of specifying the truth conditions of theoretical statements in a choice functional semantics, each giving rise to a corresponding logic of such statements. In order to investigate the inferential strength of these logical systems, we provide a translation of each truth definition into a modal definition of theoretical truth. Based on this, we show that the stronger notion of choice-semantical truth captures more adequately our informal semantic understanding of scientific statements.     

Minimum entropy production as a design criterion for breathing

Résumé La production d'entropie associée à la respiration est calculée en fonction d'une ventilation variable. En suite, pour le cas d'un métabolism donné, on évalue la ventilation qui minimise la production d'entropie due au mélange des gaz respirés et à la dissipation d'énergie associée à l'acte respiratoire. Cette ventilation optimum s'accorde avec celle observée pour des taux de métabolismes inférieurs à la consommation de 2 l d'oxygène par min.     

Scepticism,relativism and the argument from the criterion

This article explores the relationship between epistemic relativism and Pyrrhonian scepticism. It is argued that a fundamental argument for contemporary epistemic relativism derives from the Pyrrhonian problem of the criterion. Pyrrhonian scepticism is compared and contrasted with Cartesian scepticism about the external world and Humean scepticism about induction. Epistemic relativism is characterized as relativism due to the variation of epistemic norms, and is contrasted with other forms of cognitive relativism, such as truth relativism, conceptual relativism and ontological relativism. An argument from the Pyrrhonian problem of the criterion to epistemic relativism is presented, and is contrasted with three other arguments for epistemic relativism. It is argued that the argument from the criterion is the most fundamental argument for epistemic relativism. Finally, it is noted how the argument of the present paper fits with the author’s previous suggestion that a particularist response to the Pyrrhonian sceptic may be combined with a naturalistic view of epistemic warrant to meet the challenge of epistemic relativism.