Diet and high density lipoproteins

The acute and subacute effects of different diets on serum high density lipoprotein (HDL) cholesterol concentration and/or HDL composition are described. In obese normolipemic, hypercholesterolemic (type II) and hypertriglyceridemic (type IV) patients, low HDL cholesterol values remained low during total starvation for 2 weeks. Prudent diets in patients with type II and IV hyperlipoproteinemia had no significant effects on HDL cholesterol within 3 weeks, whereas in normal individuals, a high carbohydrate diet given for 10 days caused significant decreases in HDL cholesterol with concomitant increases in HDL triglycerides as compared to a high-fat diet. The HDL triglyceride fatty acid composition changed in healthy volunteers during the day, depending on the type of ingested fat. The data demonstrate the possibility of acute manipulations of HDL in normal patients and the difficulties of normalizing low HDL cholesterol levels in patients by dietary means. Additional information on the function of HDL is desirable before the therapeutic manipulation of HDL cholesterol or other constituents of HDL can be evaluated regarding their effectiveness in the prevention of ischemic vascular disease. Presented at the AOCS 69th annual meeting, May 1978, St. Louis, MO.     

Assessing the Influence of Power Pools on Emission Constrained Economic Dispatch

Power pools are formal groups of utilities that exchange electricity in order to reduce production costs. The purpose of this paper is to present a framework which assesses the impacts of different types of pooling arrangements on production costs and emissions. The framework is based on a set of economic dispatch models which simulate how different types of pools approach short-term energy exchanges. The models include constraints on emissions, system demand, spinning reserve and unit output. By varying the constraint set, trade-offs between costs and emissions across different types of pools can be quantified. To demonstrate the value of this approach, an illustrative calculation is presented for an existing pool.     

Regulation of phosphoenolpyruvate carboxykinase and fatty acid synthetase in brown fat of suckling rats

Infant rats were injected with prednisolone (0.5-5 mg/100 g wt). This caused phosphoenolpyruvate carboxykinase (PEPCK) activity to rise in liver and to decrease in brown fat. Fatty acid synthetase (FAS) activity remained unchanged in liver but increased in brown fat. A single injection of prednisolone caused hepatic PEPCK activity to remain elevated for at least 7 days. Brown fat FAS also remained high for that period. However, brown fat PEPK activity returned to normal on the third day after the injection. A single injection of prednisolone or cortisone to 5-day-old rats caused a transient elevation of the blood level of insulin and a prolonged decrease in that of growth hormone. No effect on the level of glucagon was noted. Injections of insulin had effects similar to those of prednisolone, i.e. a rise in hepatic and a fall in brown fat PEPCK. Using antibodies prepared to hepatic PEPCK it was shown that the observed changes were due to changes in the rate of synthesis of the enzyme. Using actinomycin D indirect evidence was obtained that changes in FAS activity of brown fat were also due to changes in the synthetic rate.     

Plastic zones in Fe-3Si steel double-cantilever-beam specimens

Plastic zones generated in double-cantilever-beam specimens of an Fe-3Si steel are revealed by etching. Zones corresponding to relative stress intensity levels in the range 0.4 (in.)<K/_Y< 0.8(in.), beam height to length ratios H/W = 0.125 and 0.35, and conditions approaching plane strain are examined. The fürthest extent of the zones, p 0.13 (K/_Y)², is about half that previously observed in plates loaded in tension to comparable K-levels. The results are consistent with previous, measurements by Clark and lend support to Wilson's calculations. At high stress levels, when the zone size to beam height ratio /H 0.09, the zone begins to tilt backwards and undergoes a transition from a crack- to a beam-zone. Implications of this transition with respect to the minimum beam height requirement are examined.

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Zusammenfassung In Doppelkamileverproben aus Fe-3 Si-Stahl gebildete plastische Zonen werden durch Ätzen sichtbar gemacht. Zonen welche einem relativen Spannungsintensitätsniveau im Bereich von 0,4,(in.)<K/_Y< 0,8,(in.) entsprechen, Höhen zu Längen-Verhältnisse H/W = 0,125 und 0,35 sowie Bedingungen, welche sich der planen Verformung annähern, werden untersucht.Die größte Ausbreitung dieser Zonen, 0,13 (K/_Y)² erreicht nur die Hälfte derer die früher in Blechen beobachtet worden waren, welche bei gleichen K-Werten Zugspannungen ausgesetzt wurden. Diese Ergebnisse sind in guter Übereinstimmung mit den schon von Clark durchgeführten Messungen und bekräftigen die Berechnungen von Wilson.Bei hohem Spannungsniveau, wo das Verhältnis /H 0,09 ist, beginnt die Zone sich nach rückwärts zu beugen und sich vom Rissbereich ins Innere des Trägers zu verschieben. Die sich hieraus ergebende Folgerung für die erforderliche minimale Trägerhöhe wird untersucht.

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Résumé Les zones de déformation plastique qui se développent dans des éprouvettes en forme de double poutre cantilever d'acier Fe-3Si ont été mises en évidence par attaque chimique. On envisage les zones correspondant aux conditions suivantes: niveaux relatifs de l'intensité de contraintes compris dans la fourchette: 0,4(in)<K/y<0,8(in) et rapports hauteur/longueur de poutre H/W = 0,125 et 0,350. On examine les conditions voisines de l'état plan de déformation. L'épanouissement le plus large des zones, exprimé par 0,13 (K/_Y)², est la moitié de celui que l'on a observé précédemment dans le cas de tôles sollicitées en traction à des niveaux K comparables.Ces résultats sont compatibles avec les mesures qu'a obtenues Clark, et confirment les calculs de Wilson. Sous contraintes élevées, lorsque le rapport de la dimension de la zone plastifiée à la hauteur de la poutre /H 0,09, cette zone commence à se cambrer vers l'arrière et passe de la fissure au corps même de la poutre.On examine les implications que comporte cette transition sur les hauteurs minimum de poutres à observer.

     

Crack arrest in steels

This paper examines 3 theories that have been used to characterize the arrest capabilities of steels and structures: (1) The static analysis, arrest toughness ($\text{K}{}_{\mathrm{Ia}}$) theory; (2) The dynamically loaded/stationary crack toughness ($\text{K}{}_{\mathrm{Id}}$) theory, and (3) The dynamic analysis, propagating crack energy or toughness ($\text{R}{}_{\mathrm{ID}}$ or $\text{K}{}_{\mathrm{ID}}$) theory. These three concepts are examined in the light of measurements of unstable fracture and crack arrest in wedge-loaded DCB test pieces together with a fully dynamic analysis of the experiments.     

Effect of horn flies on vanilmandelic acid excretion of dairy cattle.

This study measured a physiological effect of known horn fly (Haematoba irritans L.) population densities on dairy cattle. Urinary excretion of the catecholamine metabolite, 3-methoxy-4-hydroxy mandelic acid, was an indicator of physiological response to the parasites. Six lactating Holstein cows were acclimated to the test room prior to a 3-wk control at 21 C. Animals were then exposed to approximately 500 horn flies per cow per day for 4 wk. On days 1 and 21 of exposure, two urine samples were obtained from each cow. Mean urinary values for cows were 13.3 +/- 3.1 mug/100 ml in the control period and 18.9 +/- 3.4 mug/100 ml during fly exposure. We believe that increased vanilmandelic acid reflects an increase in standing time and nervous activity associated with the physical disturbance due to the biting of the flies.