High-Pressure Iron-Sulfur Compound, Fe3S2, and Melting Relations in the Fe-FeS System

An iron-sulfur compound (Fe3S2) was synthesized at pressures greater than 14 gigapascals in the system Fe-FeS. The formation of Fe3S2 changed the melting relations from a simple binary eutectic system to a binary system with an intermediate compound that melted incongruently. The eutectic temperature in the system at 14 gigapascals was about 400°C lower than that extrapolated from Usselman's data, implying that previous thermal models of Fe-rich planetary cores could overestimate core temperature. If it is found in a meteorite, the Fe3S2 phase could also be used to infer the minimum size of a parent body.     

Polyostotic cystic bone lesions in a dog

The clinical, radiological, and pathological features of a polyostotic cystic bone lesion in a 9-month-old Doberman Pinscher are described. The patient was diagnosed as having nutritional secondary hyperparathyroidism at 6 weeks of age and after dietary correction it remained clinically normal until 9 months when there was sudden left hind-limb lameness due to a pathological fracture through a cystic lesion in the distal femur. Radiography revealed additional cystic structures in the metaphyses of the left radius, and left and right tibia. Pseudofractures were associated with two of the cystic lesions.
In some areas the cysts were crossed by trabeculae and in others there were bony ridges on the inner cystic wall. The cavities were lined with flesh-coloured fibrillar material which formed a lacy network extending into cavities. Histologically, multiple small cysts were present adjacent to the larger cavities noted radiographically. The secondary spongiosa and the metaphyseal periosteum were the major abnormal tissue sites. The small cysts appeared to arise in an oedematous and congested metaphyseal spongiosa. The cysts were accompanied by small foci of intense osteoclasis but unattended by compensatory bone production, and the consequent possibility of pseudofractures is an important clinical consideration. Earlier reports demonstrated that resolution of the lesions will follow surgical drainage and curettage of the cystic cavity. Of six cases of polyostotic cystic bone lesions observed in the dog, five were in the Doberman Pinscher breed.     

High-Pressure Framework Silicates

Recent syntheses of high-pressure alkali and alkaline earth silicates reveal a class of framework structures with corner-linked 4- and 6-coordinated silicon. These compounds possess the structural formula (A4-2x1+Bx2+)SimVI(SinIVO2(m+n)+2), where x, m, and n specify the amounts of alkaline earth, 6-coordinated silicon, and 4-coordinated silicon, respectively. Appropriate values of m and n yield a range of high-pressure structures, from fully 4-coordinated to fully 6-coordinated silicate frameworks. Recognition of this class of framework silicates leads to predictions of high-pressure structures as well as room-pressure isomorphs of high-pressure silicates.     

Induction of heat stress in beef cattle by feeding the ergots of Claviceps purpurea

Two groups of 4 Hereford steers were housed in a controlled environment room and exposed to simulated high summer temperatures. Both groups were fed a barley grain and hay diet ad libitum. The barley in one diet contained 0.5% w/w ergots of Claviceps purpurea. Within one week of feeding the ergot diet mean rectal temperature was significantly elevated (P less than 0.05) each afternoon (up to 41 degrees C) but returned to normal overnight. Elevated rectal temperature was accompanied by other signs of heat stress, reduced feed intake, body weight loss and depression or serum prolactin concentration. Symptoms disappeared within 1 week of ceasing to feed the ergot diet.