Changes in Δ5- and Δ7-sterols during germination and seedling development ofCucurbita maximaduring germination and seedling development ofCucurbita maxima

While seeds ofCucurbita maxima contain both Δ⁵- and Δ⁷-sterols, the former, which have been described earlier, now have been found to disappear during germination. This suggests that a function exists for the Δ⁵-compounds only in the early part of the life cycle ofC. maxima, unlike most of the other higher plants studied. In contrast to the Δ⁵-sterols, the level of Δ⁷-sterols increased during germination as well as during seedling development and maturation. The period of transition between germination and seedling development appeared to be of special importance in terms of sterol changes. This period represented a surge of sterol biosynthesis with an ontogenetic shift in sterol composition from approximately equal amounts of 24α- and 24β-ethyl stereochemistry to a predominance of the former. The sterol composition of the mature plants included only about 5% of the 24β-ethylsterols. The configurational relationships were demonstrated by high resolution¹H-NMR. The sterols of the mature plants were: 25(27)-dehydrochondrillasterol, 24β-ethyl-25(27)-dehydrolathosterol, avenasterol, spinasterol, 22-dihydrospinasterol and 24ξ-methyllathosterol. Based on the changes which occurred in the relative amounts of the Δ⁷-sterols, it did not appear that the Δ⁵-components were being converted to their Δ⁷-analogs. A portion of this work was presented at the meeting of the American Oil Chemists' Society in May, 1985 in Philadelphia.     

Non-contact flood discharge measurements using an X-band pulse radar (I) theory

This article describes a non-contact method for measuring surface velocity and discharge in a natural channel. The X-band pulse (9.36 GHz) radar, developed by the Applied Physics Laboratory of the University of Washington, was used to scan instantaneously the lateral distribution of surface velocity across a river section, according to Bragg scattering from short waves produced by turbulent boils on the surface of the river. Based on the assumption that the vertical velocity distribution follows a universal power or logarithmic law, the discharges were estimated.     

On the use of confidence levels in risk management

A framework for incorporating uncertainty in risk management is developed and applied to two aspects of decision making: meeting standards or safety goals, and cost-benefit criteria. The framework is applied to several case studies including toxic chemicals in water, failure of civil engineering structures and nuclear power plants. The framework proposes that decisions be based on a level of confidence, in addition to comparing best estimate or point values with standards and goals.     

Behavioural research in telematics.

Discusses telematics, a new field of behavioral research in Canada that has grown with the technical developments in which computers and telecommunications have been combined. Three domains of behavioral research reflect relationships between humans and the technology and use the evidence and methods of different areas of psychology: (1) interface studies address perception and performance questions, (2) dialog studies focus on cognitive processes, and (3) impact studies investigate social relations and how institutions and individuals are affected by telematics. Studies conducted during the past 5 yrs by the Behavioural Research and Evaluation division of the Department of Communications, Government of Canada, are described in each of these 3 domains. Behavioral research in telematics is expected to be an increasingly important activity in which psychologists may play an active part as the technology disseminates. (French abstract) (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dealkylation of various 14-alkylsterols by the nematodeCaenorhabditis elegans

The metabolism of 4 dietary 24-alkylsterols was investigated in the free-living nematodeCaenorhabditis elegans. The major unesterified sterols ofC. elegans in media supplemented with either campesterol, 22-dihydrobrassicasterol or stigmasterol included cholesta-5,7-dienol, cholesterol, cholest-7-enol, and 4α-methylcholest-8(14)-enol. Dietary stigmastanol yielded cholest-7-enol, cholestanol, cholest-8(14)-enol, and 4α-methylcholest-8(14)-enol as major unesterified sterols. Esterified sterols comprised less than 22% of the total sterol. Removal of a C-24 ethyl substituent of sterols was neither hindered by the presence of a Δ²²-bond in the sterol side chain nor was it depedent on unsaturation in ring B of the steroid nucleus.C. elegans reduced a Δ²²-bond during its metabolism of stigmasterol; it did not introduce a Δ²²-bond during stigmastanol metabolism.C. elegans was capable of removing a C-24 methyl substituent regardless of its stereochemical orientation. Metabolic processes involving the steroid ring system of cholesterol (C-7 dehydrogenation, Δ⁵-bond, 4α-methylation, Δ⁸⁽¹⁴⁾-isomerization inC. elegans were not hindered by the presence of a 24-methyl group; various 24-methylsterol metabolites from campesterol were detected, mostly 24-methylcholesta-5,7-dienol. In contrast, no 24-ethylsterol metabolites from the dietary ethylsterols were found. More dietary 24-methylsterol remained unmetabolized than did dietary 24-ethylsterol. A 24α-ethyl group and a 24β-methyl group were dealkylated to a greater extent byC. elegans than was a 24α-methyl group, perhaps reflecting the substrate specificity of the dealkylation enzyme system, or suggesting different enzymes altogether.     

Pollution-prevention analysis and the quenching of steels

With the goal of improving process efficiency and reducing risk, this article describes a pollution-prevention analysis technique that can be applied to most secondary steel heat-treating operations involving quenching. Costs, risk assessments, and pollution-prevention options are discussed, as are the effects of quenching on two subsequent processes—parts cleaning and tempering. In contrast to many process comparisons, the issues of worker exposure, material safety and toxicity, liability, waste reduction, reclamation, and disposal are emphasized.     

Influence of regular aerobic exercise on psychological health: A randomized, controlled trial of healthy middle-aged adults.

Evaluated 120 healthy, sedentary, middle-aged adults randomly assigned to either a 6-mo home-based aerobic exercise training program or to an assessment-only control condition. Adherence across the 6-mo period by the exercise group was demonstrated by self-report and heart rate microprocessor methods to exceed 75%. A 14-item Likert rating scale was used to measure a variety of psychological variables. Significant between-groups differences favoring the exercise group were found on scale items closely associated with actual physical changes that occurred with exercise (satisfaction with shape/appearance, perceived fitness). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evacuated-tube directional-radiating cooling system

A new type of radiative cooling system is described. The radiator makes use of nonimaging optics and evacuated-tube technology to radiate significant amounts of heat to the 3 K environment of outer space. The nonimaging optics are used to direct the radiation overhead, through the most transparent part of the 8–13 μm atmospheric window. The required optical concentration is small, and relatively simple mirror geometries are possible. The evacuated-tube technology is used to attain storage temperatures at or below the freezing point, even when dewpoint temperatures are well above the freezing point.