摘要:

A comparison was made between the weight and height increases of first school children illuminated under either ‘full‐spectrum’ or ‘cold white’ fluorescent tubes. 80 children distributed between four schools were observed during 1980/81 and the experiment was repeated the following year using a similar number of children. Although significant differences in height and weight gains were found between schools no differences attributable to either sex of children or lighting treatment were detected. The results of these experiments are discussed in terms of the findings and experimental design of previous workers.

ISSN:0360-1226    

DOI:10.1080/10934528509375215

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An extensively boiled supernatant2(S2) fraction from beef round steak contains two majorSalmonellaframeshift mutagens, designated as HPLC peaks A and B. These same mutagens arise, but in different proportions, when S2is boiled with creatine phosphate (CP), and they are produced in much greater quantities from a boiled mixture of S2+L‐tryptophan (Trp) + CP + FeSO4(S2*). A third mutagen, peak C, is also generated in the S2*mixture. Mutagen peaks A, B, and C were purified to homogeneity and shown by their absorption spectra, mass fragmentation patterns, and other data to be 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ), 3‐amino‐l‐methyl‐5H‐pyrido[4,3‐b]‐indole (Trp‐P‐2), and 3‐amino‐l,4‐dimethyl‐5H‐pyrido[4,3‐b]indole (Trp‐P‐1), respectively. This is the first demonstration that IQ, Trp‐P‐2, and Trp‐P‐1 can form under aqueous conditions at 100°C from reactions between low molecular wt precursors that are present in meat juice. Further simplification of and studies with the S2fraction of beef muscle should provide relevant information about the mechanisms of frameshift mutagen formation during the cooking of meats and fish.

ISSN:0360-1226    

DOI:10.1080/10934528509375216

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528509375217

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The interactions of alkyllead salts with avian eggs were studied bothin vitroandin vivo. During 74 h incubation in viable American kestrel (Sturnus vulgaris)eggs, trialkyl and dialkylleads (each at 50 ppb as Pb) rapidly traversed biological membranes within the eggs and were accumulated in the yolk and in the developing embryo. Since the chick resorbs the yolk just prior to hatching, it will be burdened with the majority of alkylleads present in the egg. During the experiment dialkylleads but not the trialkyllead homologs were extensively degraded.

ISSN:0360-1226    

DOI:10.1080/10934528509375218

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effects of acidity on the mortality of fish (golden shiners) was studied at pH 3.7, 4.5, 5.0, 7.0, and 7.8, under controlled laboratory conditions. Results showed at pH 3.7 all fish died rapidly. As the acidity decreased, the rate of loss of fish decreased. At pH 4.5 they lived about 3 weeks and they survived pH 5.0. Aluminum was added to freshwater tanks as Al2(SO4)3and the pHof the tank adjusted slowly as necessary to avoid localization of the acid. The tanks were then allowed to equilibrate and 20 fish placed in each tank. At pH 4.5 and 5.0 plus 100ppm aluminum, all fish died within a few hours. With total aluminum concentrations of 10 ppm and 100 ppm and pH 4.5 and pH 5.0 it appeared that the aluminum and the acid had a synergistic toxic effect.

ISSN:0360-1226    

DOI:10.1080/10934528509375219

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Studies examining the sorptive characteristics of lindane to representative soil samples from New Jersey's coastal plain aquifers were performed. The soil from the Cohansey aquifer is a sand containing a 4.4 percent organic fraction. The soil from the Potomac‐Raritan‐Magothy aquifer is a sandy loam with a 2.2 percent organic fraction. Equilibrium studies exhibited linear adsorption isotherms with an association constant of 0.013 1/g for the Cohansey solids and 0.011 1/g for the Potomac‐Raritan‐Magothy solids. Desorption data indicated a pronounced hysteresis, indicating that the sorption processes for these systems were not completely reversible. Both Freundlich(indicating complete desorption) and linear (indicating incomplete desorption) isotherms were fitted to the data.

ISSN:0360-1226    

DOI:10.1080/10934528509375220

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Recovery studies using water samples fortified with 30–350 ng/L of α‐, β‐γ‐,and δ‐hexachlorocyclohexane (HCH) isomers using the Kuderna‐Danish evaporators and modified Synder column were carried out. These studies consisted of extraction, concentration and analysis by two operators on five different mixed concentrations of the four isomers with five replicates on three different days. The mean % recoveries (± standard deviation) of 98.02 ± 7.27 for the α‐, 96.61+4.88 for the β‐, 96.59+5.72 for the γ‐and 73.89 ± 11.20 for the δ‐isomers were observed. The analysis of variance between concentrations for operator 1 shows that the F ratio is significant for the isomers α‐, γ‐(p < 0.05). However, in the case of operator 2, there were significant differences between concentrations only in the case of the α‐isomer. It has also been shown that there were significant differences in operator variability for the α‐, γ‐, and δ‐isomers and that operator 2 with minimum experience could obtain consistent recoveries with β‐γ‐and δ‐HCH isomers with greater than 95% confidence. Further, a method has been described for purifying recovered hexane solvent.

ISSN:0360-1226    

DOI:10.1080/10934528509375221

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A previously reported study by Kemp and Calabrese1indicated that ascorbic acid reduces the occurrence of copper acetate‐induced methemoglobin (METHB) formationin vitro.The present study was designed to evaluate these findings in anin vivoexposure of ascorbic acid (1 gm/day) for up to four weeks with anin vitrocopper acetate incubation stress at baseline (just prior to supplementation) and at two and four weeks after initiation of treatment. The results indicated that the ascorbic acid supplementation had no significant effect on the occurrence of copper acetate induced oxidant stress (i.e. METHB increase and GSH decrease). Possible explanations for this apparent descrepancy are provided.

ISSN:0360-1226    

DOI:10.1080/10934528509375222

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528509375214

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor