Materials: unidirectional solidification of cast iron

The segregation of sulfur in liquid cast iron was studied under conditions of microgravity on Spacelab 1. A rod of cast iron containing carbon, silicon, sulfur, and phosphorus was unidirectionally solidified at four different rates. The influence of sulfur on the graphite structure and the stability of an aluminum oxide skin deposited on the surface of the specimen were investigated.     

Do bacteria-sized marine eukaryotes consume significant bacterial production?

Up to 60 percent of the total marine primary production (or about one-fourth of the total global carbon dioxide fixation) passes through the free-living bacterioplankton. Grazing by bacteriovores is probably the predominant fate of the bacteria, although data are scarce. Evidence is presented that previously uncharacterized, small eukaryotes that are able to pass even 0.6-micrometer filters may be responsible for a large fraction (more than 50 percent) of the total grazing in coastal waters. These organisms have not yet been observed microscopically.     

Influence of site and variety on starch,hemicellulose and cellulose composition of wheats and their digestibilities by adult cockerels

1. It has been shown that both the variety of wheat and the environment under which growth took place influenced the quantities of starch and cell wall carbohydrate contents of wheat.

2. The different varieties of wheat investigated contained different proportions of water‐soluble to water‐insoluble hemicelluloses.

3. By comparison of the arabinose to xylose ratios it was concluded that water‐soluble and insoluble arabinoxylans of wheat were branched to the same degree.

4. Starch from six wheat varieties grown in the U.K. was very well digested by adult cockerels and true metabolisable energy values of the wheats were high.

5. Small amounts of cell wall carbohydrates were digested by adult cockerels.     

Effects of evisceration and storage temperature on changes in meat quality of traditional farm‐fresh Turkeys

1. Conditions affecting the keeping quality of traditional farm‐fresh turkeys were investigated.

2. Storage of uneviscerated Wrolstad turkeys at 4 °C for 10 days caused no statistically significant changes in meat flavour or texture.

3. During further storage at —2 °C, however, there was a slight but significant change in flavour, which became more marked with time in birds which had been eviscerated after the initial period at 4 °C.

4. Both eviscerated and uneviscerated birds became slightly tougher during storage.

5. Initial holding at 4 °C increased the numbers of psychrotrophic bacteria on the skin by about 10³ but subsequent changes at — 2 °C were slight for uneviscerated birds.

6. Eviscerated carcases had higher counts than uneviscerated birds after storage at — 2 °C and, although ‘off’ odours were not detected, spoilage appeared to be imminent at the end of the 20‐d period.     

A toxic dipeptide from the defense glands of the colorado beetle

The Colorado beetle is protected against predators by the secretions of defensive glands located on the pronotum and the elytra. The single major compound of the secretion was identified as gamma-L-glutamyl-L-2-amino-3(Z),5-hexadienoic acid by spectroscopic and chemical methods. This compound, which contains a nonprotein beta,gamma- unsaturated amino acid, is toxic to ants (Myrmica rubra) at a concentration 10(-2) molar, which is less than its estimated concentration in the secretion (1.8 x 10(-1) molar).