Toxicity assay for deoxynivalenol using Caenorhabditis elegans

The progeny production and development rates of the nematode Caenorhabditis elegans when treated with deoxynivalenol (DON) were examined. Both purified DON and a crude extract from Fusarium graminearum cultured on rice were tested on C. elegans wild-type (Bristol N2) and a mutant strain (AU1). Significant effects (Tukey-HSD, p<0.05) on brood size and the rate of larval development from egg to adulthood were observed. Both N2 and AU1 strains showed lower rates of development and smaller brood sizes when exposed to purified DON at concentrations of 500 and 1000 μg ml(-1) When they were exposed to crude extract containing 250 μg ml(-1) DON, the inhibition of egg hatching and a greatly reduced development rate were observed. The results suggest that selection of a more sensitive C. elegans mutant strain could be used as a suitable animal model for conducting DON toxicity assays.     

Railgun performance with a two-stage light-gas gun injector

Results obtained with the HELEOS (hypervelocity experimental launcher for equation of state) railgun, which uses a two-stage light-gas gun (2SLGG) as an injector, are presented. The high-velocity 2SLGG injector preaccelerates projectiles up to ~7 km/s. The high injection velocity reduces the exposure duration of the railgun barrel to the passing high temperature plasma armature, thereby reducing the ablation and subsequent armature growth. The 2SLGG also provides a column of cool, high-pressure hydrogen gas to insulate the rails behind the projectile, thereby eliminating restrike. A means to form an armature behind the injected projectile has been developed. In preliminary tests, the third-stage railgun has successfully increased the projectile velocity by 1.35 km/s. Extensive diagnostics have been used to determine the behavior of the armature and track the launcher's performance. Insome cases, velocity increases in the railgun section have been achieved, which are in close agreement with theoretical predictions, whereas in other experiments deviations from theoretical have been observed. The reasons for and implications of these results are addressed. Recent tests are reported     

Studies on rumen metabolism. VII. Effect of lipids (in vitro) on the digestion of grass fibre and cellulose

Production of propionate from grass fibre, by rumen micro-organisms, in closed systems increased and acetate decreased over 48–72 h incubation periods when lipid was added. Similar effects of lipid on [¹⁴C] propionate and [¹⁴] Cacetate production were obtained when [¹⁴C] cellulose was added to the substrate as a marker. Total volatile fatty acid (VFA) or total [¹⁴C] VFA production from grass fibre was not affected significantly by lipid. Cod liver oil was more effective than either linseed oil or peanut oil in producing these effects. Glycerol liberated from lipid by lipolytic activity would seem to favour acetate formation, rather than propionate formation. When grass fibre was fermented in an artificial micro-rumen for 24 h, addition of oil stimulated the production of total VFA's largely due to significant increases in acetate. Relative rates of formation of the individual short chain fatty acids did not change over a 24 h period. On the other hand, less total [¹⁴C] VFA was produced from [¹⁴C] cellulose in the dialysate of the artificial micro-rumen when oil was added. The specific activities of the individual VFA's were higher without oil but maximum specific activities were obtained slightly earlier when oil was added.     

Does oral zinc aid the healing of chronic leg ulcers? A systematic literature review

OBJECTIVE: To determine whether oral zinc sulfate is an effective treatment for promoting healing of venous or arterial leg ulcers. DATA SOURCES: The search strategy of the Cochrane Wounds Group was used. This includes searches of electronic databases, conference proceedings, relevant bibliographies, and hand searching of journals. STUDY SELECTION: Studies were included if they were randomized controlled trials of oral zinc sulfate in the treatment of chronic venous or arterial ulcers with objective measures of healing. Six of the 10 studies initially identified were included in the review. DATA EXTRACTION: The trial method, participants, interventions, outcomes, baseline comparability, adequate reporting of withdrawals, and blinding of assessment were extracted by 2 reviewers independently. DATA SYNTHESIS: No trial showed a statistically significant benefit of zinc sulfate for healing leg ulcers. There is limited evidence to suggest that zinc might increase healing in individuals with a low serum zinc level, but more evidence is needed. CONCLUSIONS: There is no evidence of benefit from the general use of zinc sulfate in patients with chronic leg ulcers. There is a need for further research to see if oral zinc sulfate is beneficial in the treatment of patients with leg ulcers who have a low serum zinc level. If it is demonstrated to be beneficial, further trials are required to establish dose and duration of treatment.     

Hydrogen insertion compounds of UO3

Hydrogen-insertion compounds, H_xUO₃, of two polymorphs of UO₃ have been prepared. Unit-cell dimensions have been determined by Guinier powder X-ray analysis and are compared with those of the parent oxide. Infra-red spectra of these phases are also presented and discussed.     

Studies on rumen metabolism. V.—formation of branched long chain fatty acids in cultures of rumen bacteria

When mixed rumen bacteria were incubated with isobutyrate-1-¹⁴C, the ¹⁴C-label was incorporated into branched long chain fatty acids with both odd and even numbers of carbon atoms. Tracer studies showed that the ¹⁴C-label from DL-valine-4-¹⁴C was incorporated into branched long chain fatty acids and also into straight chain fatty acids with odd numbers of carbon atoms. In addition, labelled isobutyrate and propionate were synthesised from valine and probably represent intermediates in the synthesis of the branched and straight chain fatty acids respectively.     

Positional distribution of fatty acids in the triglycerides of bovine milk fat with elevated levels of linoleic acid

A stereospecific distribution of fatty acids in bovine milk fat containing 15.5% linoleic acid has been compared with the distribution in bovine milk fat containing a normal level (1.8%) of linoleic acid. The positional distribution was obtained by the separate analysis of milk fat triglycerides of high, medium, and low molecular weight. The order of preference for linoleic acid in the high molecular weight triglycerides was position 3>position 2 >position 1. There was an accompanying altered distribution of myristic acid and palmitic acid in favor of position 1 at the expense of position 3. However, the proportions of myristic acid and palmitic acid in position 2, relative to positions 1 and 3 were identifical in the high molecular weight fractions of the two milk fats. The distribution of linoleic acid in the medium molecular weight triglycrides of linoleic-rich milk fat was position 1=position 2>position 3. This resulted in a change in the distribution of 18 carbon monounsaturated fatty acids in favor of position 2 at the expense of position 1, but the distribution of myristic acid and palmitic acid was virtually unaltered. The distribution of linoleic acid in the low molecular weight triglycerides was position 2>position 1>position 3. The amounts of myristic acid and palmitic acid in position 2 and of palmitic acid in position 1 decreased in the low molecular weight triglycerides of the milk fat containing elevated levels of linoleic acid. Changes in the distribution of fatty acids which were observed in the separate analysis of the high, medium, and low molecular weight triglycerides were not apparent when comparing the distribution in the total milk fats. For example, the distribution of myristic acid and palmitic acid appeared to be unchanged, while the distribution of 18 carbon monounsaturated fatty acids was slightly altered in favor of positions 2 and 3. Moreover, linoleic acid showed an almost equal preference for the three positions of the glycerol moiety in milk fat containing elevated levels of this fatty acid with some concentration at position 2.     

Influence of elevated levels of linoleic acid on the thermal properties of bovine milk fat

The thermal properties of bovine milk fat containing 15.5% linoleic acid have been compared with those of milk fat containing a normal level (1.8%) of linoleic acid in order to examine the influence of altered triglyceride (TG) composition on their physical characteristics. The total TGs of 18∶2-rich milk fat melted over the range −38 to 30 C compared with the range −33 to 34 C for control milk fat. Polymorphism exhibited by the high mol wt TGs of control milk fat was absent in the same fraction of 18∶2-rich milk fat. Similarly, the complex melting thermogram of the low mol wt TGs of control milk fat and its obvious polymorphic behavior contrasted with the single broad melting peak of the low mol wt TGs of 18∶2-rich milk fat. This solid miscibility in the 18∶2-rich milk fat could be a consequence of the lower proportion of saturated TGs or the presence of high proportions of diene and triene TGs containing 18∶2 instead of monoene and diene TGs containing 18∶1.