Studying examiners reports

Kister et al. [213] have concluded from examining reported cases of cross-flow channeling related to poor sieve tray column performance that under specific conditions the cross-flow channeling does occur. See Figure 8-142 [213] for diagram of the postulated vapor flow across a tray. It is known to occur for valve trays and bubble cap trays. This condition has not been studied very much in the open literature however, several investigators including myself have observed in industrial practice the... 

The self-reactions of 2-carboalkoxy-2-propyl radicals (8-10) have been examined.89 Ia> 104 The results of these studies are reported in Table 5.3. Combination is slightly favored over disproportionation. The value of kjkw for 8 was found to be essentially independent of temperature. 

Arakawa Wada (1993) dosed rats with mono-methyltin trichloride or dimethyltin dichloride for 10 days at 5 mg/kg body weight per day and reported no effects on thymus weight this is the only study examining immunotoxic end-points for the methyltins. 

Photolysis studies of methyl parathion have been reported. A study examining the photodegradation of methyl parathion in river and seawater at variable temperatures showed the half-lives to be 11 and 34 days, respectively (Lartiges and Garrigues 1995). During photolysis in natural water 50% of the... 

Two sets of data involving multiple substitution at nonequivalent sites have been examined. The sets studied are reported in Table XLV (sets 45-51, 45-52). Results of the correlations are set forth in Table XLVI. Significant correlations were obtained for both sets of data. 

Renal Effects. Hemorrhage of the medullary layer of the kidneys was observed in an early report of three fatal cases of acute oral poisoning with endosulfan (Terziev et al. 1974). More recent studies have reported acute renal failure after ingestion of endosulfan as a major contributing cause of death in two individuals in both cases, postmortem examination showed extensive tubular necrosis (Blanco-Coronado et al. 1992 Lo et al. 1995). Neither case discussed the possible mechanism of endosulfan-induced acute renal failure, but in one case, the authors of the report indicate that the renal lesions may relate to sepsis and shock (Blanco-Coronado et al. 1992). Ingested doses were not determined in any of these cases, and it is not totally clear that the effects observed at autopsy were a direct result of endosulfan exposure, although based on results from acute animal studies, it seems likely. 

A technique utilizing genetically modified bacteria to report the presence of particular compounds in soil has also been developed (37). These bacteria respond to the presence of specific compounds in their environment by producing ice-nucleation proteins that enter into cell membranes, enabling cells to be detected by means of a droplet freezing assay. The presence of trytophan in 1-10 i molar concentrations has been detected using reporter bacteria in a study examining loss of amino acids from roots of Avena barbata into soil (38). 

No studies were located regarding interactions with other substances in humans or animals after exposure to diisopropyl methylphosphonate. However, the potential for multiple chemical interactions does exist. Diisopropyl methylphosphonate has been identified in the RMA in the presence of many other chemicals (such as endrin, dieldrin, dicyclopentadiene, bicycloheptdiene, diethyl benzene, and diethyl disulfide). The nervous system is a target of many of these compounds found at the RMA, including diisopropyl methylphosphonate. Therefore, there is potential for interaction, and studies examining multiple exposures would be useful in predicting risk to humans. Workers at the RMA reported skin irritation after dermal exposure to diisopropyl methylphosphonate at concentrations around 11.3 ppm in water. However, several other chemicals were also in the area (NIOSH 1981). Therefore, it is not clear if diisopropyl methylphosphonate contributed to the effects. 

Immunotoxicity. The data in humans are limited to a few studies of immune function in lead workers and a study of firearm instructors. In both type of studies, inhalation is assumed to be the primary route of exposure. One study reported significant suppression of IgA levels (Ewers et al. 1982). Another study indicated that serum immunoglobulin levels were not significantly altered (Alomran and Shleamoon 1988). Another large study examined several parameters of immune function (serum immunoglobulins, PHA response, and natural killer cell activity) and found no differences in exposed workers and controls (Kimber et al. 1986b). The study of firearm instructors found functional impairment of cell-mediated immunity in subjects with PbB levels >25 pg/dL (Fischbein et al. 1993). A recent study that evaluated a... 

Cr3+ and Cr6+ are the most stable oxidation states of chromium, but with the only difference that while +3 oxidation state is cationic where as the +6 oxdation state is oxoanionic. However, the other oxidation states of +1, +2, +4 and +5 are also known for chromium, especially in aqueous solution at different pH. Inter-conversion of these oxidation states too is very frequent. With this view, an attempt is made here to examine the effect of ultrasound on the inter-convertibility of chromium among various oxidation states in aqueous solutions. The details of this study is reported in the literature [36]. 

The hypothesis of the role of HA in wakefulness stems from the observation that administration of the classical antihistamines (i.e. H3 receptor antagonists) induced sedation. These first-generation antihistamines, used to treat inflammatory reactions, could cross the blood-brain barrier and block the central Hi receptor (White Rumbold, 1988). The first study examining the effect of antihistamines on sleep-wakefulness in cats reported an increase in NREM sleep and a decrease in REM sleep (Jewett, 1968). Similar results were also obtained in dogs (Wauquier et ah, 1981) and humans (Risberg et ah, 1975 Bassano Caille, 1979 Nicholson et ah, 1985 Adam Oswald, 1986). Intraventricular application of HA in the anesthetized rat caused a dose-dependent decrease in the duration of narcosis, whereas intraventricular application of HA in conscious... 

To further explore possible mechanisms of carbon-carbon bond formation, we have examined the reaction of Cp2Fe2(C0K with LiAlHi, (LAH). This reaction yields hydrocarbon products up to butane.— The results of this study are reported herein. 

A number of studies in humans show that PUFAs can generate significant immunomodulatory effects. Generally, these studies have utilized considerably lower amounts of fish oil to treat subjects than found in most animal studies. Numerous clinical trials have examined the effects of fish oil on rheumatoid arthritis and many have reported statistically significant benefits such as decreased morning stiffness and numbers of tender joints [57]. Several other studies have reported that PUFAs can provide therapeutic benefits for patients with IgA nephropathy, the most common primary human glomerulonephritis... 

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