Equivalent exposure

DE is the equivalent exposure for the working shift, or daily exposure... 

Equivalent exposure The exposure to a harmful product experienced by a worker. It is the sum of the exposure fraction of each component in a mixture. 

In capillary shear studies involving M. citrifolia, the extent of cell damage was found to increase with the prevailing level of shear stress (Fig. 2). Trials involving capillary tubes of different lengths yielded similar levels of viability loss at equivalent exposure times, indicating that the death rate is determined by the shear stress alone. 

Selected conditions and results are shown in Table 2 that are representative of the catalyst performance. Continuous testing of the Ni/Re catalyst compared favorably with the baseline data generated for this catalyst in the batch reactor screening. At 200°C, the overall activity of the catalyst appeared slightly higher in the continuous reactor, achieving 94% conversion at a weight hourly space velocity of 2.5hr 1 (g xylitol/g catalyst/h) and 200°C compared to 88% conversion at an equivalent exposure in the batch reactor of 2.1 hr"1 (g xylitol/g catalyst/h) achieved at the 4 hour sample at 200°C. 

The TEF approach normalizes exposures to common mechanism chemicals with different potencies to yield a total equivalent exposure (TEQ) to one of the chemicals, the index compound. TEFs are derived as the ratio of the POD of the index compound to that of each member in the group. The exposure to each chemical is then multiplied by the respective TEF value to express exposure in terms of the index compound. Summation of these values result in the total combined exposure (TEQ) expressed in terms of the index compound. 

Wilkinson et al. (2000) used the information in Table 10.2, chose compound IV as the index compound (TFF= 1), assigned TEF values to compounds I (0.05), II (0.01), and III (0.2) and calculated the total compound IV equivalent exposure (TEQ) to 0.042 mg/kg bw/day. When this TEQ was compared to the RfD of compound IV (0.05 mg/kg bw/day), a value of 0.84 was obtained, representing a kind of combined HQs that indicates that 84% of the risk cup was filled. This risk estimate will be the same regardless which compound is selected as the index compound, provided that the AF for each member in the group is the same (Table 10.2, scenario A). 

As long as radiation dose equivalent exposures are low, radiation damage is non-detectable. General effects of short-term radiation exposure are summarized in Table 17.5. The dose equivalents in Table 17.5 are listed in rems. These values are several orders of magnitude greater than what humans received in a year. Annual human exposure... 

TEOA triethanolamine. All activators were present in equimolar amounts and films received equivalent exposure (see note f). 

Manipulation of the A, FT, and />, values in Eq. (11) will naturally produce different values of B. Accordingly, if it is desirable that B be as low as possible, this may be accomplished in one of three ways (1) reducing the bioburden A of the bulk product, (2) increasing the equivalent exposure time FT, or (3) employing a micro-organism with a lower D value at the specified temperature. Since option 3 most likely is impossible, as the most resistant micro-organisms of a fixed D value must be used in sterilizer validation, one must either employ techniques to assure the lowest possible measurable microbial bioburden prior to sterilization or simply increase the sterilization cycle time. 

BCF values measured in fish exposed to both water and sediment were much lower than equivalent exposures to water only and ranged from 2,500 to 5,800 (Adams et al. 1986 Cook et al. 1991 Tsushimoto et al. 1982) (Table 5-3). Loonen et al. (1993) also reported that bioaccumulation of CDDs was reduced in the presence of sediment and that the effects of sediment increased with increasing hydrophobicity (degree of chlorination) of the congeners. BCFs were reduced by 15-82% for various CDD/CDF congeners, with the greatest reduction associated with OCDD. 

Ern is the equivalent exposure of an individual to a mixture which is defined as follows ... 

Some experiments show traces of acetone, methylene chloride, chloroform, benzene, and dioxane in the air. Only in one instance (chloroform) was a TLV exceeded. However, pump error may have caused this result. When many solvents or air contaminants coexist in the environment, a total or equivalent exposure must be calculated. The equivalent exposure reflects the contribution of each contaminant to the total exposure. In these studies this value was very low and can be noted in the next to last column of Table II. Solvents like benzene, chloroform, and dioxane are presently suspected carcinogens (j>) and laboratory instructors should replace these compounds with safe substitutes whenever possible. 

The erosion yields that are reported in the literature almost always come from exposures where the Kapton-equivalent exposure fluence was >10 atoms cm . These erosion yields represent the material removal process that occurs under steady-state erosion conditions. Mass loss mea surements on hydrocarbon materials that were deposited on quartz crystal microbalances have shown that there is an induction period, sometimes involving an initial mass gain, before the erosion yield of a polymer becomes linear with fluence. This linear, or steady-state, behavior is typically reached before a fluence of 10 atoms cm, so reported erosion yields are only sensitive to the surface chemistry that is occurring after the induction period. 

Extended-release (ER) divalproex (valproate semisodium) is not bioequivalent to delayed-release (DR) divalproex. In a randomized, crossover study in 36 healthy volunteers the bioequivalence of divalproex ER once a day and divalproex DR at 14% and 20% lower daily doses given twice a day were compared (122). The two formulations gave equivalent exposure (AUC) with lower peak and higher trough concentrations, that is less fluctuation during the dosage interval, with divalproex DR. 

In their seminal work, Heiz and coworkers used temperature-programmed reaction (TPR) on a model planar catalyst support (MgO) upon which size-selected Au (n= 1-20) clusters were deposited [6]. Approximately 20 oxygen molecules per Au atom were dosed on the surface at 90 K followed by an equivalent exposure of CO. 

In an alternate fuel fabrication technique, crushed or spherical fuel particles are vibratory-packed directly into the cladding tubes, thereby avoiding the problems of pellet production. The fabrication operations can be carried out automatically by remote operation at room temperature. Dust contamination is avoided, as well as radiation exposure of personnel. Irradiation tests of these fuel rods indicate improved performance over pellet fueled rods for equivalent exposures " . 

Figure 12-3 Thrombocytopenia in dogs given ABT-263, but not its inactive enantiomer, at equivalent exposures. Adapted by permission from Macmillan Publishers Ltd Cell Death and Differentiation, 14, 943-51, copyright (2007).

Provide confidence that the pharmacological model will predict efficacy in humans. If a drag is effective in therapeutic models using different species and these animals receive equivalent exposures (as measured by the maximum plasma concentration, Cmax, or area under the plasma concentration curve, AUC), then the clinician can choose a dose for trials with confidence. 

The exposure concentration was converted to a human equivalent exposure concentration (853 mg/m3) by multiplying by the ratio of the alveolar ventilation rate divided by the body weight of mice to the same parameters for humans. The human equivalent concentration was divided by an uncertainty factor of 300 (10 for interspecies variability, 3 for intraspecies variability, and 10 for the use of a LOAEL) to derive the MRL. 

Ghittori S. Imbriani M. Pezzagno G, et al. 1987. The urinary concentration of solvents as a biological indicator of exposure Proposal for the biological equivalent exposure limit for nine solvents. Am Ind Hyg Assoc J 48 786-790. 

Example 2.2 Oxidized copper 3" x 3" billets are being heated in an electrically heated furnace that has an average heat source temperature of 1600 F. The refractory area is five times the exposed metal area. The loading arrangement is such that the equivalent exposure to furnace radiation is only 6 in. of the 12" periphery of each billet. The billet weight is 34.9 Ib/ft of length. 

Nava (1971) suggested a definitive allergy to the vitamin B12 molecule or to a vitamin Bj2 protein complex. In his report, the hypersensitivity to vitamin Bj2 of 110 people was induced by occupational exposure to cyanocobalamin in 50 cases and by drug-equivalent exposure in 60 cases. He could exclude the possibility of... 

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