Single organ, chemicals 428 / INDEX

Risk Index for Multiple Substances That Cause Stochastic Responses. The risk index for mixtures of substances that cause stochastic responses (radionuclides and chemicals) is based on an assumption of a linear, nonthreshold dose-response relationship. This risk index takes into account the stochastic risk in all organs or tissues, and it assumes that the risk in any organ is independent of risks in any other organs. Based on these conditions, and expressing the risk index for a single hazardous substance in terms of dose (see Equation 6.3), the risk index for mixtures of substances that cause stochastic responses, denoted by RIS, can be expressed as ... 

A substance is said to be chemically pure when it is made up of identical atoms and molecules. This means that the concept of purity can only apply to a single element or compound. As essential oils are made up of mixtures of organic compounds, they cannot be strictly chemically pure. Chemical purity and composition have to be related to an odour profile and be free from any contamination. Standard samples are used for reference when considering the purity of an essential oil, and the analytical techniques of GC-MS, refractive index and other methods previously described are applied. A standard sample or standard oil is a sample of a product that conforms to a specification for that product. It is kept for purposes of comparison with batch samples and used in quality evaluation. 

The conversion of chemical names and identihers into appropriate chemical structure representations offers the ideal path for chemists and organizations to mine chemical information. Because chemical names are not unique and a multitude of labels can map to a single chemical entity, the facile conversion of alphanumeric text identihers to a connection table representation enables superior data capture, representation, indexing, and mining. The industry s need to mine more information from both the historical corpus as well as new sources is obvious, and a number of researchers have initiated research into the domain of chemical identiher text mining and conversion. Multiple efforts have been made in the held of bioinformatics research,8 and, while interesting as a parallel, in this chapter we will focus the efforts to extract and convert identihers related to chemical entities rather than, for example, genes, enzymes, or proteins. 

The Ethyl Corp. (I, p. 173) has a Remington-Rand installation for indexing the properties of fuel and lubricant additives. Both chemical structure and additive properties are coded on a single card. The use of the selective sorter, which will permit sorting in 12 adjacent columns simultaneously, and well-organized prefiling of the cards have made this an extremely workable file without the... 

Examples of studies of specific adsorption are presented in Tables 4.1 (small cations), 4.2 (small anions), 4.4 (organic compounds). 4.5 (surfactants), and 4.6 (polymers). Studies presenting new experimental data are compiled together with discussions, interpretations and model calculations based on experimental results taken from other publications. The tables are sorted primarily by the chemical formula of the adsorbent, according to the rules outlined in the Introduction, and then by the adsorbate. The entries with a single adsorbate are followed by entries with multiple adsorbates (for the same adsorbent) sorted by the name or chemical formula of the first adsorbate, then of the second adsorbate, etc. Each Table is accompanied by an alphabetical index of adsorbates. 

Organizations such as the Chemical Abstacts Service and the BeUstein Institute that prepare indexes to the chemical literature must adopt a system for selecting unique names in order to avoid excessive cross referencing. Chemical Abstracts Service uses a system which groups together compounds derived from a single parent compound. Thus most index names are inverted (e.g.. Benzene, bromo rather than bromobenzene Acetic acid, sodium salt rather than sodium acetate). 

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