Attenuation chemical

Grammatopoulos, T.N., Morris, K., Bachar, C., Moore, S., Andres, R., and Weyhenmeyer, J.A. 2004. Angiotensin II attenuates chemical hypoxia-induced caspase-3 activation in primary cortical neuronal cultures. Brain Res. Bull. 62 297-303. 

By focusing on customer-driven development, American Aerogel has successfully commercialized a form of aerogel materials. Aerocore, a black organic monohthic open cellular rigid foam, can be produced with a wide range of properties and sizes. It can be used as a thermal insulator, acoustic attenuator, chemical support media, electrical conductor, and mechanical shock absorber. 

Illman, Walter, and Pedro Alvarez. Performance Assessment of Bioremediation and Natural Attenuation. Critical Reviews in Environmental Science and Technology 39, no. 4 (April, 2009) 209-270. Reviews state-of-art performance assessment methods and discusses future research directions in bioremediation, natural attenuation, chemical fingerprinting, and molecular biological tools. 

Pervushin K, Riek R, Wider G and Wuthrich K 1997 Attenuated T relaxation by mutual cancellation of dipole-dipole coupling and chemical shift anisotropy indicates an avenue to NMR structures of very... 

In absorption spectroscopy a beam of electromagnetic radiation passes through a sample. Much of the radiation is transmitted without a loss in intensity. At selected frequencies, however, the radiation s intensity is attenuated. This process of attenuation is called absorption. Two general requirements must be met if an analyte is to absorb electromagnetic radiation. The first requirement is that there must be a mechanism by which the radiation s electric field or magnetic field interacts with the analyte. For ultraviolet and visible radiation, this interaction involves the electronic energy of valence electrons. A chemical bond s vibrational energy is altered by the absorbance of infrared radiation. A more detailed treatment of this interaction, and its importance in deter-... 

There are many iadustrial appHcations for radioisotopes. A simple example is the determination of the thickness of some item that is being formed, or of the density of a flow stream ia a chemical process, by measuting the attenuation of or y-radiation as it passes through the material. Another... 

M. W. AT2rs1, Attenuated Total Reflectance Spectroscopy of Polymers Theory and Practice, American Chemical Society, Washington, D.C., 1996. 

Ex situ bioremediation may use various biological wastewater treatment processes, soil piles, or land appHcation. With in situ bioremediation, the basic process is the same microbes, soil, and water working together as a bioreactor. Where the in situ techniques differ are in how contaminants and microbes are brought in contact and how oxygen, nutrients, and other chemical supplements ate distributed in the soil—water—air matrix. Typical in situ bioremediation techniques include natural or intrinsic attenuation, air sparging, and bioventing. 

Inherent safety Inventory reduction Fewer chemicals inventoried or fewer in process vessels. Chemical substitution Substitute a less hazardous chemical for one more hazardous. Fr ocess attenuation Use lower temperatures and pressures. 

Storage and receiving are activities that can greatly contribute to a safe and economic operation. It is here that quality control can be achieved at minimal cost. Label verification and other quality assurance measures can increase the confidence level that the correct chemicals have arrived, thereby potentially circumventing the use of wrong chemicals. Wrongly shipped chemicals can be returned to the manufacturer with minimal or no cost to the batch operation owner. As with all processes and activities it is of great importance to apply the principles of inherent safety, in particular the minimization and attenuation principles (CCPS G- 41). 

The most common monitoring of particulate matter is for light attenuation (opacity). Less frequently used methods exist for monitoring mass concentration, size distribution, and chemical composition. 

Moderate means using materials under less hazardous conditions, also called attenuation. Moderation of conditions can be accomplished by strategies which are either physical (lower temperatures, dilution) or chemical (development of a reaction chemistry which operates at less severe conditions). 

The proportion of ionized and unionized forms of a chemical compound can be readily calculated according to the above equation. It can be easily seen that pK is also a pH value at which 50% of the compound exists in ionized form. The ionization of weak acids increases as the pH increases, whereas the ionization of weak bases increases when the pH decreases. As the proportion of an ionized chemical increases, the diffusion of the chemical through the biological membranes is greatly impaired, and this attenuates toxicokinetic processes. For example, the common drug acetosalicylic acid (aspirin), a weak acid, is readily absorbed from the stomach because most of its dose is in an unionized form at the acidic pH of the stomach. 

A number of chemical compounds are potent sensitizers that can lead to serious immunological reactions. Immunotoxicology explores interactions between chemical compounds and the immune system. Chemicals can amplify, attenuate, or otherwise modify immunological reactions subsequent to exposure. - ... 

Methyl chloride, determination by x-ray absorptiometry, 84 Mica, attenuation of x-rays by, 45 Microanalysis, use of x-rays in histo-chemical and eytochemical, 296-305... 

While electron or ion beam techniques can only be applied under ultra-high vacuum, optical techniques have no specific requirements concerning sample environment and are generally easier to use. The surface information which can be obtained is, however, quite different and mostly does not contain direct chemical information. While with infra-red attenuated total reflection spectroscopy (IR-ATR) a deep surface area with a typical depth of some micrometers is investigated, other techniques like phase-measurement interference microscopy (PMIM) have, due to interference effects, a much better surface sensitivity. PMIM is a very quick technique for surface roughness and homogeneity inspection with subnanometer resolution. 

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