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  • Author: William J. Brown x
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Abstract

Ternary copper(II) complexes containing the dianion of 3-n-nonylcatechol and a number of bidentate nitrogen containing counter ligands have been prepared and characterized. It has been demonstrated that, in the presence of oxygen, the catecholato ligand undergoes intradiol ring cleavage in a fashion similar to that carried out by intradiol aromatic dioxygenases. The 3-n-nonylcatecholato ligand was chosen as an analog for the naturally occuring 3-pentadecylcatechols or "urushiols" which are the active allergens in plants such as poison ivy.

Abstract

Dioxygenase Model, Copper, Catechol The complex (3-n-nonylcatecholato)(1,10-phenanthroline)copper(II) reacts with molecular oxygen to give an isomeric mixture of 2-n-nonylmuconic acid and several secondary oxidation products. The catecholato ligand is oxidatively cleaved in an intradiol fashion reminescent of the reactions catalyzed by intradiol aromatic dioxygenases. The 1,10-phenanthroline ligand can be quantitatively recovered and is not oxidized. In addition to characterization of oxidation products, the kinetics of oxygen consumption have been analyzed. The rate law for oxygen uptake is -d[O2]/dt = k[O2] [copper]2 .

Abstract

A platinum-wound resistance furnace for the Buerger precession camera has been designed. Temperatures up to 1300°C can be attained. The crystal is mounted directly on a thermocouple attached to the goniometer head. The position of the crystal in the furnace affects inversely the cone angle of the emergent x-rays and the temperature gradient across the crystal; a compromise between these two must be made.

Abstract

Precession x-ray photographs showed that single crystals of MgSiO3 obtained from the Norton meteorite converted to proto-enstatite between 1050 ± 50°C and 1300°C (the upper limit of the apparatus). Diffractometer study of synthetic MgSiO3 showed that proto-enstatite forms up to about 1440°C.

Proto-enstatite, upon cooling from high temperature, converted into a variety of products ranging from twinned clino-enstatite through disordered structures to a product similar to ortho-enstatite, but with stacking faults. Rapid quenching produced clino-enstatite or disordered material closely related to it. Slow cooling through the range 800–1000°C sometimes produced partly disordered material similar to ortho-enstatite.

From consideration of these and earlier results by many investigators on both natural and synthetic enstatites, it is concluded that ortho-enstatite is the form stable below 1000°C while proto-enstatite is stable above this temperature, and that clino-enstatite and the disordered enstatites are metastable forms, occurring because they grow faster than ortho-enstatite.

Disordered enstatites similar to those produced by the cooling of protoenstatite have been found in the Norton County and Cumberland Falls meteorites. Twinned clino-enstatite was found in the Juvinas meteorite. The occurrence of such enstatites may give information on the temperature history of meteorites, though it is possible that shearing stress may cause similar structural disorder.

Abstract

Relationships between sprinting speed, body mass, and vertical jump kinetics were assessed in 243 male soccer athletes ranging from 10-19 years. Participants ran a maximal 36.6 meter sprint; times at 9.1 (10 y) and 36.6 m (40 y) were determined using an electronic timing system. Body mass was measured by means of an electronic scale and body composition using a 3-site skinfold measurement completed by a skilled technician. Countermovement vertical jumps were performed on a force platform - from this test peak force was measured and peak power and vertical jump height were calculated. It was determined that age (r=-0.59; p<0.01), body mass (r=-0.52; p<0.01), lean mass (r=-0.61; p<0.01), vertical jump height (r=-0.67; p<0.01), peak power (r=-0.64; p<0.01), and peak force (r=-0.56; p<0.01) were correlated with time at 9.1 meters. Time-to-complete a 36.6 meter sprint was correlated with age (r=-0.71; p<0.01), body mass (r=- 0.67; p<0.01), lean mass (r=-0.76; p<0.01), vertical jump height (r=-0.75; p<0.01), peak power (r=-0.78; p<0.01), and peak force (r=-0.69; p<0.01). These data indicate that soccer coaches desiring to improve speed in their athletes should devote substantive time to fitness programs that increase lean body mass and vertical force as well as power generating capabilities of their athletes. Additionally, vertical jump testing, with or without a force platform, may be a useful tool to screen soccer athletes for speed potential.