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The odor detection threshold for phosgene is 0.4 ppm, four times the threshold limit value (time weighted average). Its high toxicity arises from the action of the phosgene on the −OH , −NH 2 and −SH groups of the proteins in pulmonary alveoli (the site of gas exchange), respectively forming ester, amide and thioester functional groups in ...
The OSHA definition is arguably broad enough to include oxygen-deficient circumstances in the absence of "airborne contaminants", as well as many other chemical, thermal, or pneumatic hazards to life or health (e.g., pure helium, super-cooled or super-heated air, hyperbaric or hypo-baric or submerged chambers, etc.).
Toxic: a chemical that has a median lethal concentration (LC 50) in air of more than 200 parts per million (ppm) but not more than 2,000 parts per million by volume of gas or vapor, or more than 2 milligrams per liter but not more than 20 milligrams per liter of mist, fume or dust, when administered by continuous inhalation for 1 hour (or less if death occurs within 1 hour) to albino rats ...
These tests can measure and compare a control threshold (or resting threshold) to a threshold produced by a change in the environment, by a preceding single impulse, an impulse train, or a subthreshold current. [9] Measuring changes in threshold can indicate changes in membrane potential, axonal properties, and/or the integrity of the myelin ...
Threshold Limit Values (TLVs), often determined by the American Conference of Governmental Industrial Hygienists (ACGHI), is a key component in determining the PEL. [11] [10] Other things that contribute to determining the PEL are toxicity and particle size. [10] PELs for chemicals are measured in mg/M 3 (milligrams per cubic meter). [2]
As an action potential (nerve impulse) travels down an axon there is a change in electric polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na +) and potassium- (K +)–gated ion channels open and close as the membrane reaches its threshold potential.
Phosgene reacts with water to form carbon dioxide and HCl, [77] and the carbonate salt neutralizes the resulting acid. [ 78 ] Suspected samples can be tested for phosgene using filter paper which when treated with 5% diphenylamine , 5% dimethylaminobenzaldehyde in ethanol , and then dried, turns yellow in the presence of phosgene vapour. [ 79 ]
Examples of graded potentials. Graded potentials are changes in membrane potential that vary according to the size of the stimulus, as opposed to being all-or-none.They include diverse potentials such as receptor potentials, electrotonic potentials, subthreshold membrane potential oscillations, slow-wave potential, pacemaker potentials, and synaptic potentials.