The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
Tee L. Guidotti - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen sulfide intoxication
Handbook of Clinical Neurology, 2015Co-Authors: Tee L. GuidottiAbstract:Hydrogen sulfide (H2S) is a hazard primarily in the oil and gas industry, agriculture, sewage and animal waste handling, construction (asphalt operations and disturbing marshy terrain), and other settings where organic material decomposes under reducing conditions, and in geothermal operations. It is an insoluble gas, heavier than air, with a very low odor threshold and high toxicity, driven by concentration more than duration of exposure. Toxicity presents in a unique, reliable, and characteristic toxidrome consisting, in ascending order of exposure, of mucosal irritation, especially of the eye ("gas eye"), Olfactory paralysis (not to be confused with Olfactory Fatigue), sudden but reversible loss of consciousness ("knockdown"), pulmonary edema (with an unusually favorable prognosis), and death (probably with apnea contributing). The risk of chronic neurcognitive changes is controversial, with the best evidence at high exposure levels and after knockdowns, which are frequently accompanied by head injury or oxygen deprivation. Treatment cannot be initiated promptly in the prehospital phase, and currently rests primarily on supportive care, hyperbaric oxygen, and nitrite administration. The mechanism of action for sublethal neurotoxicity and knockdown is clearly not inhibition of cytochrome oxidase c, as generally assumed, although this may play a role in overwhelming exposures. High levels of endogenous sulfide are found in the brain, presumably relating to the function of hydrogen sulfide as a gaseous neurotransmitter and immunomodulator. Prevention requires control of exposure and rigorous training to stop doomed rescue attempts attempted without self-contained breathing apparatus, especially in confined spaces, and in sudden release in the oil and gas sector, which result in multiple avoidable deaths.
Phil Reed - One of the best experts on this subject based on the ideXlab platform.
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Serial position effects in recognition memory for odors.
Journal of experimental psychology. Learning memory and cognition, 2000Co-Authors: Phil ReedAbstract:Five experiments examined recognition memory for sequentially presented odors. Participants were presented with a sequence of odors and then had to identify an odor from the list in a test probe containing 2 odors. All experiments demonstrated enhanced recognition of odors presented at the start and end of a series, compared with those presented in the middle of the series when a 3-s retention interval between list termination and test was used. In Experiments 2 and 3, when a 30-s or 60-s retention interval was used, participants performed at slightly lower levels, although the serial position function was similar to that obtained with the 3-s retention interval. These results were noted with a 5-item (Experiments 1 and 4), 7-item (Experiment 2), 6-item (Experiment 3), and 4-item (Experiment 5) list of odors. As the number of test trials increased, recognition performance decreased, indicating a strong role for Olfactory Fatigue or interference in these procedures. A verbal suppression task, used in Experiments 4 and 5, had little influence on serial-position-based performance.
Kathryn Hodder - One of the best experts on this subject based on the ideXlab platform.
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Serial position effects in recognition memory for odors: A reexamination
Memory & Cognition, 2005Co-Authors: Christopher Miles, Kathryn HodderAbstract:Seven experiments examined recognition memory for sequentially presented odors. Following Reed (2000), participants were presented with a sequence of odors and then required to identify an odor from the sequence in a test probe comprising 2 odors. The pattern of results obtained by Reed (2000, although statistically marginal) demonstrated enhanced recognition for odors presented at the start (primacy) and end (recency) of the sequence: a result that we failed to replicate in any of the experiments reported here. Experiments 1 and 3 were designed to replicate Reed (2000), employing five-item and seven-item sequences, respectively, and each demonstrated significant recency, with evidence of primacy in Experiment 3 only. Experiment 2 replicated Experiment 1, with reduced interstimulus intervals, and produced a null effect of serial position. The ease with which the odors could be verbally labeled was manipulated in Experiments 4 and 5. Nameable odors produced a null effect of serial position (Experiment 4), and hard-to-name odors produced a pronounced recency effect (Experiment 5); nevertheless, overall rates of recognition were remarkably similar for the two experiments at around 70%. Articulatory suppression reduced recognition accuracy (Experiment 6), but recency was again present in the absence of primacy. Odor recognition performance was immune to the effects of an interleaved odor (Experiment 7), and, again, both primacy and recency effects were absent. There was no evidence of Olfactory Fatigue: Recognition accuracy improved across trials (Experiment 1). It is argued that the results of the experiments reported here are generally consistent with that body of work employing hard-to-name visual stimuli, where recency is obtained in the absence of primacy when the retention interval is short.
Christopher Miles - One of the best experts on this subject based on the ideXlab platform.
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Serial position effects in recognition memory for odors: A reexamination
Memory & Cognition, 2005Co-Authors: Christopher Miles, Kathryn HodderAbstract:Seven experiments examined recognition memory for sequentially presented odors. Following Reed (2000), participants were presented with a sequence of odors and then required to identify an odor from the sequence in a test probe comprising 2 odors. The pattern of results obtained by Reed (2000, although statistically marginal) demonstrated enhanced recognition for odors presented at the start (primacy) and end (recency) of the sequence: a result that we failed to replicate in any of the experiments reported here. Experiments 1 and 3 were designed to replicate Reed (2000), employing five-item and seven-item sequences, respectively, and each demonstrated significant recency, with evidence of primacy in Experiment 3 only. Experiment 2 replicated Experiment 1, with reduced interstimulus intervals, and produced a null effect of serial position. The ease with which the odors could be verbally labeled was manipulated in Experiments 4 and 5. Nameable odors produced a null effect of serial position (Experiment 4), and hard-to-name odors produced a pronounced recency effect (Experiment 5); nevertheless, overall rates of recognition were remarkably similar for the two experiments at around 70%. Articulatory suppression reduced recognition accuracy (Experiment 6), but recency was again present in the absence of primacy. Odor recognition performance was immune to the effects of an interleaved odor (Experiment 7), and, again, both primacy and recency effects were absent. There was no evidence of Olfactory Fatigue: Recognition accuracy improved across trials (Experiment 1). It is argued that the results of the experiments reported here are generally consistent with that body of work employing hard-to-name visual stimuli, where recency is obtained in the absence of primacy when the retention interval is short.
Dong Hyun Kim - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen sulfide intoxication with dilated cardiomyopathy.
Journal of occupational health, 2009Co-Authors: Eui-cheol Lee, Jun Kwan, Jong Han Leem, Shin-goo Park, Hwan-cheol Kim, Dong-hoon Lee, Jeong Hoon Kim, Dong Hyun KimAbstract:Hydrogen sulfide (H 2 S) is a colorless, heavier-than-air, inflammable, highly toxic irritant and chemical asphyxiant gas, which has a characteristic rotten-egg odor that is detectable at concentrations as low as 0.5 ppb, but this warning property may be lost in 2 to 15 min at concentrations over 100 ppm through Olfactory Fatigue . Hydrogen sulfide is generated naturally by decaying sulfur-containing proteins and is released from sewage sludge, liquid manure, sulfur hot springs, and natural gas. It is also a by-product of many industrial processes, including petroleum refining, sewage disposal, mining, wood pulp processing, rayon manufacturing, manure processing, sugar-beet processing, fish processing and hot-asphalt paving . Hydrogen sulfide is especially risky in confined spaces such as fishing-ship holders, manure pits, and sewers. In the United States, 52 deaths related to hydrogen sulfide were reported from 1993 to 1999 in various industries. The toxic mechanism of hydrogen sulfide comprises inactivating cytochrome oxidase in mitochondria and then preventing the cellular metabolism of oxygen. Via this mechanism, hydrogen sulfide can induce hypoxic brain damage and hypoxic cardiac damage as well as mucosal irritation and pulmonary edema. Nevertheless, few cases of cardiac damage following hydrogen sulfide exposure have been reported. We here report a case of dilated cardiomyopathy after hydrogen sulfide inhalation in a sewer worker, the first case report of dilated cardiomyopathy caused by hydrogen sulfide. Case Presentation
