Delay effect

Toxicity. Sodium fluoroacetate is one of the most effective all-purpose rodenticides known (18). It is highly toxic to all species of rats tested and can be used either in water solution or in bait preparations. Its absence of objectionable taste and odor and its delayed effects lead to its excellent acceptance by rodents. It is nonvolatile, chemically stable, and not toxic or irritating to the unbroken skin of workers. Rats do not appear to develop any significant tolerance to this compound from nonlethal doses. However, it is extremely dangerous to humans, to common household pets, and to farm animals, and should only be used by experienced personnel. The rodent carcasses should be collected and destroyed since they remain poisonous for a long period of time to any animal that eats them. 

Hydrogen chloride is produced when PVC bums. A series of tests for the Federal Aviation Administration studied this issue. In those studies, test animals were able to survive exposures to hydrogen chloride reaching 10,000 ppm (190). More recent studies indicate less of a potential for delayed effects on lung function than expected (191). In a typical fire, hydrogen chloride levels rarely exceed 300 ppm, a fact confirmed by the Boston Fire Department and Harvard University (192). In hundreds of autopsies conducted on fire victims in the United States, not one death has been linked to the presence of PVC. 

Cover the control of substances classified as very toxic, toxic, harmful, coiTosive, sensitizing or imtant under the Chemicals (Hazard Information and Packaging for Supply) Regulations 1994 (as amended) and to substances which have MELs or OESs. Also other substances that have chronic or delayed effects and biological agents. Special provisions are included for carcinogens. 

A serious exposure may also result from a small, single dose over a short period of time and there is no immediate effect. This small dose may exceed t e threshold sensitivity of the individual causing a serious delayed effect. The classic exeimple of this is cancer. 

Doses from several small exposures over a pjcriod of time (chronic exposure) causing no immediate effect, may also result in a delayed effect. This cumulative effect may be serious or minor. 

Suhacute toxicity Rats/mice 2. 2 weeks Delayed effects, target organs... 

Subchronic study Rats/mice/dogs/rabbits 6 months Target organs, delayed effects... 

In the process of burning, toxic compds are formed, which may produce delayed effects on personnel exposed to the smoke (Ref 7, p 101) Triethylaluminum (TEA). A number of organo-metallic compds are spontaneously inflammable in air. Others, like organosodium and organo-potassium compds, are not only spontaneously inflammable in air but react violently with w and carbon dioxide (Ref 4, p 24)... 

George J, Andrade C, Joseph T. 1992. Delayed effects of acute oral and chronic inhalational exposure to methyl parathion on learning and memory in rats. Indian J Exp Biol 30 819-822. 

Antithyroid drugs have a delayed effect. After 2 to 4 weeks of therapy, adjust the dose if the TSH is not in the target range (0.5-2.5 milliunits/L). Once the patient is euthyroid, consider reducing the dose of antithyroid drug to avoid hypothyroidism. 

Consideration of Indirect and Delayed Effects (such as those from GHGs and CFCs). 

The time delay effect is canceled out, and this equation at the summing point is equivalent to a system without dead time (where the forward path is C = GCGE). With simple block diagram algebra, we can also show that the closed-loop characteristic polynomial with the Smith predictor... 

Addition of the dehydrated salt to acetic anhydride caused an exothermic reaction which accelerated to explosion. Presence of acetic acid (including that produced by hydrolysis of the anhydride by the hydrate water) has a delaying effect on the onset of violent reaction, which occurs where the proportion of anhydride to acid (after hydrolysis) exceeds 0.37 1, with an initial temperature above 35°C. Mixtures of dichromate (30 g) with anhydride-acid mixtures (70 g, to give ratios of 2 1, 1 1, 0.37 1) originally at 40°C accelerated out of control after 18, 43 and 120 min, to 160, 155 and 115°C, respectively. 

Flury and Zemik (1931) also reported no immediate or delayed effects in a human exposed at 6.25 ppm for 30-60 min. 

This material is hazardous through inhalation, skin absorption (high doses), penetration through broken skin, and ingestion. Delayed effects from exposure to high concentrations include disintegration of red blood cells. Symptoms include drowsiness, weakness, vomiting, respiratory distress, diarrhea, convulsions, shock, low body temperature, and death. 

This degree of lowering of brain inositol would not appear to be sufficiently near the Km of PI synthase to slow PI synthesis. It has also been observed that Li+ must be administered for many days before a therapeutic effect is seen. This suggests that delayed effects of Li+, such as regulation of enzymes, might better correlate with the clinical effect. While the inositol depletion hypothesis appears attractive in many respects, its validity remains to be demonstrated. A number of other biochemical sites of Li+ action have been reported [3,4], and it maybe that multiple actions of Li+ are necessary for its clinical effectiveness. 

Significant adverse effects of zinc on growth, survival, and reproduction occur in representative sensitive species of aquatic plants, protozoans, sponges, molluscs, crustaceans, echinoderms, fishes, and amphibians at nominal water concentrations between 10 and 25 pg Zn/L (Table 9.6). Latent effects of zinc intoxication after brief exposures are poorly documented. One study showed that sensitive species of freshwater crustaceans exposed to zinc concentrations as low as 150 pg/L for as little as 30 minutes had delayed effects that included increasing immobility for up to 172 hours after exposure (Brent and Herricks 1998). 

Chemical agents can cause immediate effects biological agents cause delayed effects. 

Type D Delayed effects (e.g., carcinogenicity, teratogenicity) Low incidence... 

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