Exposure, defined

Time scaling may not be applicable to halogenated hydrocarbons as blood concentrations of these chemicals do not increase as exposure time is increased beyond 5-10 min (Bakshi et al. 1998). In the Utell et al. (1997) study with human volunteers exposed to HCFC-141b, the relationship between exposure concentration and blood level was linear and reached equilibrium at 250 ppm within 145 min. Graphical representation of the exposure time-blood concentration indicated that at the higher concentrations, equilibrium was approached at 225 min, and at 55 min concentrations were within 80% of the 225 min concentration. Furthermore, the circulating HCFC-141b concentration, rather than duration of exposure, defines whether or not a cardiac response will occur. 

Strictly, natural exposure can be carried out for any of the environmental agents. For example, if the product is to spend its life in water at 70 °C then exposure to water at 70 °C can be considered natural ageing. Exposure to water at 80 °C could be called natural ageing at worst possible conditions or with a safety factor. Natural exposure defined in this way is carried out by adapting the standard laboratory methods for air ageing and exposure to liquids as there are no specific natural exposure standards. 

Numerous pollutants are discharged directly into the atmosphere by human industry, where winds may transport them to Earth s most remote corners. It is important, however, to note that industry is not the sole source of contaminants individuals also contribute to this problem through the use of household pesticides and fertilizers, improper disposal of hazardous materials (e.g., used motor oil, paints, cleaning products), and even by driving the family car. Consequently, sites with one predominant contaminant are a rarity complex mixtures and subsequent exposures define the real world. 

If the COH-3 is restricted to that normally obtained with commercially available AZ351 developer at various normally used dilutions (. 05-.25 molar in OH" concentration), it is possible to make a linear approximation to the data obtained by Hinsberg for the conditions of exposure defined by Hinsberg and a dissolution rate equation for exposed resist ... 

A large body of literature on health effects of lead exposure and faetors that influence lead toxicity has been published sinee the 1978 OSHA standard was established. Most recently, the US National Toxicology Program (NTP) released a monograph on the health effects of low-level lead exposure, defined by the NTP as BLLs of under 10 gg/dL and in some eases under 5 gg/dL. The... 

Tielemans E, Schneider T, Goede H, Tischer M, van Henunen JJ, Warren N, Van Tongeren M, Cherrie J (2008) Ctmceptual model for inhalation exposure defining modifying factms. Arm Occup... 

Exposure. Exposure defines contact of a hazard with a specific set of conditions. For physical hazards, exposure defines the conditions under which the hazard will be expressed. For example, methanol must be exposed to temperatures at or above the flash point of 52°F (11°C) in order to express the hazard of flammability. 

A spreadsheet was developed to collect data from the field. To estimate the daily personal noise exposure defined in accordance with the gathered information, a characterization of the productive process regarding the distribution of the different work stations/task, was made. For that purpose, an interval time of exposure was assigned. 

Dominican and African American (Washington Heights, Central Harlem, and South Bronx) (Perera et al., 2012) 6-7 years CBCL High PAH exposure, defined as greater than the median exposure from personal air monitoring, or detectable and higher maternal and cord adducts, was associated with symptoms of Anxious/ Depressed and Attention Problems (P < 0.05)... 

Ain pollution (qv), lecognized in the National Ambient Aii Quality Standards (NAAQS) as being chaiactetized by a time—dosage lelationship, is defined as the presence in the atmosphere (or ambient ain) of one or more contaminants of such quantity and duration as may be injutious to human, plants, or animal life, property, or conduct of business (1,2). Thus, ain pollutants may be rendered less harmhil by reducing the concentration of contaminants, the exposure time, or both. 

Conclusion. The quantitative measurements, their interpretation, the calculated statistics, and the exposure criteria all come together to arrive at a conclusion to be drawn with a known chance of being wrong. The data and their interpretation give the extent of the conclusion. The exposure criteria, its origin and basis, define the impact of a conclusion that conditions are unsafe. 

It is difficult to define the normal range of iodine intake in humans, and despite efforts to provide iodine supplementation in many geographic areas of the world, endemic iodine deficiency and attendant goiter remain a world health problem (147). Exposure to excess iodine may sometimes lead to the development of thyroid disease. This unusual type of iodide-induced goiter has been found, for example, in 10% of the population of a Japanese island where fishermen and their families consume large quantities of an iodine-rich seaweed and have an iodine intake as high as 200 mg/d (148). 

Safety Standards. Protection from laser beams involves not allowing laser radiation at a level higher than a maximum permissible exposure level to strike the human body. Maximum permissible exposure levels for both eyes and skin have been defined (55—57). One of the most common safety measures is the use of protective eyewear. Manufacturers of laser safety eyewear commonly specify the attenuation at various laser wavelengths. Under some conditions safety eyewear has been known to shatter or to be burned through (58), and it is not adequate to protect a wearer staring directly into the beam. 

Several additional terms related to the absorption of x-radiation require definition energy of a x-ray photon is properly represented in joules but more conveniently reported in eV fluence is the sum of the energy in a unit area intensity or flux is the fluence per unit time and the exposure is a measure of the number of ions produced in a mass of gas. The unit of exposure in medicine is the Rn ntgen, R, defined as the quantity of radiation required to produce 2.58 x C/kg of air. The absorbed dose for a tissue is a measure of energy dissipated per unit mass. The measure of absorbed dose most... 

Olfactory receptors have been a subject of great interest (9). Much that has been postulated was done by analogy to the sense of sight in which there are a limited number of receptor types and, as a consequence, only three primary colors. Thus attempts have been made to recognize primary odors that can combine to produce all of the odors that can be perceived. Evidence for this includes rough correlations of odors with chemical stmctural types and the existence in some individuals having specific anosmias. Cross-adaptation studies, in which exposure to one odorant temporarily reduces the perception of a chemically related one, also fit into this hypothetical framework. Implicit in this theory is the idea that there is a small number of well-defined odor receptors, so that eventually the shape and charge distribution of a specific receptor can be learned and the kinds of molecular stmctures for a specified odor can be deduced. 

Lightfastness is measured by exposing pigmented film to an artificial or natural, eg, Florida exposure, light for a predetermined time. It is a relative term where the color of a sample exposed to a known light source is compared to its original color values. To make it meaningful, aH conditions of the exposure have to be weH defined. 

A chemical microsensor can be defined as an extremely small device that detects components in gases or Hquids (52—55). Ideally, such a sensor generates a response which either varies with the nature or concentration of the material or is reversible for repeated cycles of exposure. Of the many types of microsensors that have been described (56), three are the most prominent the chemiresistor, the bulk-wave piezoelectric quartz crystal sensor, and the surface acoustic wave (saw) device (57). 

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