Chemical class, definition

Reducing agents present similar problems. They react with a broad spectrum of chemical classes, and the reactions can be exothermic and violent. Reducing agents are, by definition, highly oxidizable and may react with air or moisture in the air. Common reducing agents include ... 

Lead exposure Not a substitute for effective abatement of lead exposure. Neutropenia Mild to moderate neutropenia has been observed in some patients receiving succimer. While a causal relationship to succimer has not been definitely established, neutropenia has been reported with other drugs in the same chemical class. Obtain a complete blood count with white blood cell differential and direct platelet counts prior to and weekly during treatment. Withhold or discontinue therapy if the absolute neutrophil count (ANC) is below 1200/mcL and follow the patient closely to document recovery of the ANC to above 1500/mcL or to the patient s baseline neutrophil count. There is limited experience with reexposure in patients who have developed neutropenia. Therefore, rechallenge such patients only if the benefit of succimer therapy clearly outweighs the potential risk of another episode of... 

Related to the Schedule 1 family of alkyl/cyclo-alkyl alkylphosphonofluoridates, are three important classes of compounds. These are the dialkyl/dicyclo-alkyl alkylphosphonates, the alkyl/cycloalkyl alkylphosphonates and the methyl alkyl/cycloalkyl alkylphosphonates, all belonging to the Schedule 2.B.4 chemicals. Per definition, Schedule 2.B.4 represents the largest number of chemicals of CWC interest. The first class consists of known impurities of nerve agents, the second class consists of the primarily formed hydrolysis products of nerve agents, and the third class, the corresponding methyl esters-DMMP (dimethyl methylphosphonate) and DIMP (diisopropyl methylphosphonate) (see Table 1) are... 

The main strength of the Snyder scheme is for the classification of solvent selectivity. We have seen from table 2.8 that solvents that are chemically similar yield similar selectivity parameters. This type of classification can be made on the basis of structural information alone. However, the Snyder scheme goes one step further, in that it classifies different chemical classes into a single selectivity group. From the definition equations (2.14 through 2.17) we see that the three selectivity parameters are correlated by the equation... 

Generally, it will save time to locate subclasses through patent numbers obtained from Chemical Abstracts, rather than via the index to the manual and the class definitions. This is in part due to the complexity of many of the definitions, which tend to be more confusing than clarifying until one has become thoroughly familiar with the method and style of presentation. 

Humic substances are those organic compounds found in the environment that cannot be classified as any other chemical class of compounds (e.g., polysaccharides, proteins, etc.). They are traditionally defined according to their solubilities. Fulvic acids are those organic materials that are soluble in water at all pH values. Humic acids are those materials that are insoluble at acidic pH values (pH < 2) but are soluble at higher pH values. Humin is the fraction of natural organic materials that is insoluble in water at all pH values. These definitions reflect the traditional methods for separating the different fractions from the original mixture. 

The two populations of 5-HT receptors that have been definitely linked to depression are the 5-HT, and the 5-HT receptors. Numerous 5-HT, antagonists are available and belong to a multitude of chemical classes structure-activity relationships are well beyond the scope of this chapter and several reviews are available (e.g., 151,210,211). 5-HT, receptors consist of three families 5-HT , S-HTgB, and 5-HT . An important issue at this time is which one (or more) of these subpopulations is most involved in depression. This question remains to be answered. Another issue is that 5-HT receptors have been linked to cardiac valvulopathy (212). Hence, future development of 5-HT, ligands might wish to avoid agents with high affinity for 5-HT receptors. 

Analyte or non-analyte specific (Can be chemical class specific) Non-qualitative to semi-qualitative, non-definitive (unconfirmed) identification. Non-definitive quantitation no confidence limits. 

The most commonly used diuretics are invariably classified by their respective chemical class, mechanism of action, site of action, or effects on the urine contents. Nevertheless, these drugs normally exert their action rather widely with regard to their prevailing efficacy as well as their definite site of action located within the nephron. The real efficacy of a diuretic is often measured by its ability to enhance the rate of excretion of Na ions filtered usually at the glomerulus i.e., the filtered load of sodimn) and hence, must not be misunderstood with the potency, that is the actual amount of the diuretic essentially needed to cause a specific diuretic response. In other words, the efficacy of a diuretic is invariably estimated in portion by the site of action of the diuretic. 

The following are only examples. Not all members of the above classes may be or may become shock sensitive. Likewise, some chemicals in classes not listed above may be or may become shock sensitive. Currently there is no available methodology that would allow DOE to create a thorough definition or an exhaustive list of shock sensitive or potentially shock sensitive chemicals. Additional lists of chemicals or chemical classes of shock sensitive chemicals have been published (2, 4, 5, 12, 15, 23). 

Material Safety Data Sheets, which are now required to be provided by distributors and manufacturers of commercial chemicals, give detailed information on the characteristics of all commonly sold laboratory chemicals. The definitions of explosive, flammable, combustible, and various healthhazards are consistent with those provided by OSHA in CFR 29, Parts Table 3.2 Exemption Limits for a Few Critical Classes of Materials Representing Health Hazards For a Class 4, Hazardous Use Occupancy... 

The observation that features enriched in sets of active compounds irrespective of potency enables retrieval of highly potent compounds also supports the usage of feature weights extracted from NBM to identify compound-class characteristic molecular features. So far, we have discussed only activity classes, but any way to group molecules can be used to identify features that preferentially occur in desired groups of compounds. Other examples of compound class definition include ADME characteristics [24], toxicity [21 ], clinical ADRs [35], or chemical... 

The first part of this paper discusses factors that govern the multiplexing capability of TN-LCD, and introduces some definitions of figure of merit. For various chemical classes of LCs such as Schiff s base, esters, biphenyls, azoxy and cyclohexanes, their physical properties and their relationship to display performance are discussed. We classify those LCs into three categories, Ng (weakly positive dielectric anisotropy nematic LC) and Nj +Np (binary mixed system of negative and positive dielectric anisotropy nematic LC). An evaluation of each class is given. 

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