Multiple chemical sensitivity reactions

In addition to the proteins discussed above, a large number of reactive chemicals used in industry can cause asthma and rhinitis. Hypersensitivity pneumonias have also been described. Isocyanates and acid anhydrides are industrial chemicals that cause occupational asthma. Acid anhydrides, such as phthalic anhydride, seem to cause mainly type I reactions, whereas the IgE-mediated mechanism explains only a part of the sensitizations to isocyanates. Several mechanisms have been suggested, but despite intensive research no models have been generally accepted. The situation is even more obscure for other sensitizing chemicals therefore, the term specific chemical hypersensitivity is often used for chemical allergies. This term should not be confused with multiple chemical sensitivity (MCS) syndrome, which is a controversial term referring to hypersusceptibility to very low levels of environmental chemicals. ... 

What is MCS MCS stands for multiple chemical sensitivity. People who suffer from this condition get sick from all sorts of everyday (synthetic) chemical substances and/or scents. Many cannot lead normal lives because these substances are found almost everywhere. These chemically sensitive people get sick from chemical substances, even low doses to which healthy people do not display any noticeable reaction and might not even know are there. 

In many cases, multiple chemical sensitivity symptoms result from classical conditioning. An initial exposure causes emotional reactions during or after the exposure odor acts as a future trigger or conditioned stimulus for symptoms. Symptoms result from autonomic hyperactivity from fear of exposure (Amundsen et al. 1996 Bolla-Wilson et al. 1988 Schottenfeld 1987 Shusterman and Dager 1991). 

The affliction of environmental illness, otherwise known as multiple chemical sensitivity (mcs), rendered the ordinary spaces of late capitalist life uninhabitable. brings together diverse individualized experiences of multiple symptoms that sufferers typically link to mild exposures of many unrelated chemicals. Like sick building syndrome, MCS is a phenomenon with a multiplicitous nature. Because individualized reactions are difficult, if not impossible, to objectify with conventional biomedical techniques and because they are elicited by low, subtoxic, supposedly safe levels of common, unrelated chemicals, the very existence of mcs was highly controversial in the late twentieth century, and it remains so. mcs does not conform to the biomedical logics already available for categorizing bodily states, nor does it conform to biomedical expectations of what a body is supposed to be able to do. 

As illustrated by the examples above, the possibility of removing the generated heat from the reaction zone decreases with an increase in reactor size. As proven above, it can happen that the temperature of the reaction mixture in a full-scale reactor becomes higher than in the laboratory flask reactor. If multiple chemical reactions of distinctly different temperature sensitivities take place, differences in yields and selectivities between small and large reactors will be observed. This has a large influence on safety also. The laboratory reactor might still show satisfactory performance, while the industrial reactor might even explode. 

Although the inhibition-based biosensors are sensitive, they are poor in selectivity and are rather slow and tedious since the analysis involves multiple steps of reaction such as measuring initial enzyme activity, incubation with inhibitor, measurement of residual activity, and regeneration and washing. Biosensors based on direct pesticide hydrolysis are more straightforward. The OPH hydrolyzes ester in a number of organophospho-rus pesticides (OPPs) and insecticides (e.g. paraoxon, parathion, coumaphos, diazinon) and chemical warfare agents (e.g. sarin) [53], For example, OP parathion hydrolyzes by the OPH to form p-nitrophenol, which can be measured by anodic oxidation. Rainina... 

The reactivity of size-selected transition-metal cluster ions has been studied witli various types of mass spectrometric teclmiques [1 ]. Fourier-transfonn ion cyclotron resonance (FT-ICR) is a particularly powerful teclmique in which a cluster ion can be stored and cooled before experimentation. Thus, multiple reaction steps can be followed in FT-ICR, in addition to its high sensitivity and mass resolution. Many chemical reaction studies of transition-metal clusters witli simple reactants and hydrocarbons have been carried out using FT-ICR [49, 58]. 

T cells control these learned responses and decide which tools to use in the reaction. Sometimes they choose several different tools at once, and multiple reactions ensue, such as when a person becomes sensitized to penicillin and has not only anaphylaxis but hemolytic anemia and serum sickness. There are different types of T cells, and they communicate either directly with other cells or by chemical messages called cytokines. The pattern of cytokines released is one way T cells have of determining which kind of response will occur. They are broadly called Thl andTh2 responses, with Thl mostly responding to infections and Th2 often producing allergy or asthma. 

A number of new resist materials which provide very high sensitivities have been developed in recent years [1-3]. In general, these systems owe their high sensitivity to the achievement of chemical amplification, a process which ensures that each photoevent is used in a multiplicative fashion to generate a cascade of successive reactions. Examples of such systems include the electron-beam induced [4] ringopening polymerization of oxacyclobutanes, the acid-catalyzed thermolysis of polymer side-chains [5-6] or the acid-catalyzed thermolytic fragmentation of polymer main-chains [7], Other important examples of the chemical amplification process are found in resist systems based on the free-radical photocrosslinking of acrylated polyols [8]. 

Dry sodium hydride is available from Aldrich Chemical Company, Inc., as a fine powder. In multiple runs, it is most convenient to weigh the bulk reagent into 100-g (one reaction) lots. Extreme care should be used in handling this moisture-sensitive, flammable solid. 

The reaction of water sensitive compounds with alumina surfaces is complicated not only by the multiplicity of the surface hydroxyl groups but also by the Lewis acid centers which can give a strong physical adsorption of the compound without chemical reaction. 

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