摘要:

Kinetics studies on the interaction between lead dioxide and methylcobalamin indicate a pattern of two parallel first‐order reactions with rate constants of 1.02 x 10‐3s‐1and 5.33 x 10‐5s‐1. The relative importance of the two reaction pathways seems to depend on the available surface of lead dioxide. Acetone, methane and methanol form as the principal gaseous products. Traces of tetramethyllead form, and substantial quantities of lead dissolve in the aqueous layer. The product distribution is consistent with a mechanism involving formation and decomposition of methyllead triacetate. Other insoluble metal oxides also follow this pattern in their reaction with methylcobalamin.

ISSN:0360-1226    

DOI:10.1080/10934528309375116

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A total of 216 male Sprague‐Dawley rats were used. Animals were injected IP every 3 days for 29 days for a total of 9 injections with 0, 1.0 or 2.5 mg Cd/kg body wt. Total cumulative doses were 0, 9.0 or 22.5 mg Cd/kg body wt. Twenty‐four hrs after the last Cd injection (day 30), each animal was subjected to an acute sublethal total‐body exposure of 0, 362 or 543 rads of gamma (60Co) irradiation at a dose rate of 304 rads/min. Eight rats from each of the 9 groups were sacrificed by cardiac exsanguination on post‐irradiation day 1, 7 or 21.

ISSN:0360-1226    

DOI:10.1080/10934528309375117

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A joint research program was initiated in 1979 to investigate the potential avian repellency and toxicity of 55 selected insect repellents originating from or related to naturally occurring chemicals. Seven of the chemicals or extracts tested exhibited avian repellency and two of these were considered to be moderately active, with R50’s (analogous to LD50) of 0.237 (trans‐asarone) and 0.240% (safrole). None of the 55 chemicals or extracts exhibited acute oral toxicity at 100 mg/kg or less to the red‐winged blackbird (Agelaius phoeniceus).

ISSN:0360-1226    

DOI:10.1080/10934528309375118

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Carcinogenicity of the fungicide fenaminosulf (p‐dimethylami‐nobenzenediazosodium sulfonate) and one of its bacterial metabolite, dimethyl‐p‐phenylenediamine (DMPDA) was evaluated in rats. Over a 17 month period, rats fed with 250 mg of the compounds per kg of feed (in the presence or absence of nitrite) did not develop tumors. Phenols were detected in the urine and faeces of rats receiving either fenaminosulf or DMPDA suggesting possible detoxification of these compounds. These compounds being positive in mutagenicity screening tests in the bacteria, in the light of our present studies it is suggested that testing potential carcinogens in experimental animals is a pre‐requisite before arriving at definitive conclusions on the carcinogenicity of chemicals.

ISSN:0360-1226    

DOI:10.1080/10934528309375119

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Aqueous extracts of peat‐like sediments from Lake Starvation, Hillsborough County, Florida, inhibit the growth ofHydrilla verticillatain laboratory systems. The extracts were obtained by autoclaving sediment in water, and it may be that this process degrades the sediment. Evidence is presented that the total organic content of the extract obtained is not substantially different from solutions obtained at much lower temperatures. Therefore, the use of autoclaving in the preparation of sediment extract would appear to produce a material similar to that possibly produced in the environments of selected lakes.

ISSN:0360-1226    

DOI:10.1080/10934528309375120

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The selective removal of some C10olefinic terpenes from hydrocarbon mixtures was investigated since direct gas chromatographic analysis of mixtures of these compounds is hampered by severe peak overlaps. A HgSO4‐H2SO4precolumn stripper was used to efficiently strip several C10olefinic terpenes from complex mixtures of other hydrocarbons. This procedure permits investigators to identify and measure terpenes accurately both in rural forested areas and in urban areas.

ISSN:0360-1226    

DOI:10.1080/10934528309375121

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

During 1978–80 a survey was conducted to ascertain the prevalence ofSalmonellain raccoons (Procyon lotor)in Indiana. The animals were live‐trapped and their feces and mesenteric lymph nodes cultured for salmonellae. Of the total 106 raccoons examined, 43 salmonellae isolations were made from 33 animals (33.1%). The mesenteric lymph nodes from 8 of 20 raccoons which were necropsied contained salmonellae. Twelve serotypes were identified. Two harbored 3 serotypes, while 7 others were colonized with 2 serotypes. Urban origin raccoons were 30.8%Salmonellapositive, while 34.7% of the rural raccoons yielded the pathogens. Among the adults, 29.6% were positive and 33.3% of the immature animals harbored salmonellae. The most frequently isolated organism wasS. typhimurium(35%) and its variant, Copenhagen. The antibiograms of theSalmonellaisolates were ascertained using 12 antimicrobials. Resistance to common antimicrobials used in veterinary practice was minimal.

ISSN:0360-1226    

DOI:10.1080/10934528309375122

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Data from the analyses of reference samples often must be used to determine the quality of the data being produced by laboratories that routinely make chemical analyses of environmental samples. When a laboratory analyzes many reference samples, binomial distributions can be used in evaluating laboratory performance. The number of standard deviations (that is, the difference between the reported value and most probable value divided by the theoretical standard deviation) is calculated for each analysis. Individual values exceeding two standard deviations are considered unacceptable, and a binomial distribution is used to determine if overall performance is satisfactory or unsatisfactory. Similarly, analytical bias is examined by applying a binomial distribution to the number of positive and negative standard deviations.

ISSN:0360-1226    

DOI:10.1080/10934528309375123

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Effect of short‐term exposure to 5 ppm of nitrogen dioxide (NO2) for 3 consecutive days on endogenous rat heart, serum and liver lactate dehydrogenase (LDH) was studied in male rats maintained on water or on10%ethanol solution as the sole drinking fluid for 10 days preceding and during NO2exposure. Animals were pair‐fed. Measurements of hepatic alcohol and aldehyde dehydrogenase were also made. Exposure to NO2had little effect on body or liver weights from corresponding controls maintained on water. Ethanol intake increased liver weight in controls and in NO2‐treated rats. Endogenous heart LDH was significantly increased by the NO2exposure compared to water drinking controls. Ethanol intake negated this effect on LDH in NO2‐exposed animals. Kinetic studies on NO2‐mediated action on heart LDH indicate higher Vmaxand apparent Kmvalues in NO2‐treated rats than in the corresponding controls, compared to normal values in NO2‐exposed ethanol drinking rats and their respective controls. No changes occurred in serum or in liver LDH or in hepatic ethanol and acetaldehyde metabolizing enzymes studied as a function of the NO2exposure or the ethanol drinking. The results suggest that specific alteration of heart LDH without concomitant changes in serum LDH may reflect an early indication of cardiac injury by NO2exposure.

ISSN:0360-1226    

DOI:10.1080/10934528309375124

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This research evaluated the treatability of a pentachlorophenol wastewater (PCPWW) from a wood‐preserving plant. The treatment efficiencies of a naturally occurring microbial system, a commercially available “mutant”; or specialized population, and a combination of the two, while undergoing acclimation to full‐strength PCPWW in 21 days were studied. TOC and COD removals averaged less than 35 percent. The decay rates (k‐rates) for the three biological test systems were significantly lower than those typically associated with domestic wastewater. No significant differences were observed in treatment efficiencies measured as TOC and COD.

ISSN:0360-1226    

DOI:10.1080/10934528309375125

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor