Age-related changes in the metabolism of cholesterol in rat liver microsomes

The effects of aging on the hepatic metabolism of cholesterol were studied in 1-, 6- and 24-month-old male Sprague-Dawley rats. Microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, which regulates cholesterol biosynthesis, decreased from 835±144 (SEM) pmol/min/mg protein in the youngest group to 219±34 and 205±53 pmol/min/mg protein (p<0.001) in the 6- and 24-month-old groups, respectively. Cholesterol 7α-hydroxylase activity, which governs bile acid synthesis, was gradually reduced from 70±14 pmol/min/mg protein in the 1-month-old group to 32±7 and 16±3 pmol/min/mg protein (p<0.05) in the 6- and 24-month-old groups, respectively. Acyl coenzyme A:cholesterol acyltransferase activity, which catalyzes the esterification of cholesterol, averaged 431±47 and 452 ±48 pmol/min/mg protein in the 1- and 6-month-old groups, respectively, and was increased to 585±55 pmol/min/mg protein (p<0.05) in the 24-month-old group. The level of total cholesterol showed an age-related increase from 1.56±0.16 mg/g liver in the 1-month-old group to 1.70±0.15 and 2.20±0.19 mg/g liver (p<0.05) in the 6- and 24-month-old groups, respectively. The increase was mainly caused by an accumulation of esterified cholesterol. We conclude that a marked decrease in HMG-CoA reductase occurs between 1 and 6 months of age; thereafter the enzyme activity stays unchanged. The activity of cholesterol 7α-hydroxylase decreases progressively and drastically with age, whereas the capacity for esterifying cholesterol increases slightly. We speculate that the reduced conversion of cholesterol to bile acids may be one explanation of the age-related increase of plasma cholesterol seen in rats.     

Reaktion von Hydroperoxiden mit Radikalen

2,4,6-Tri-tert.-butyl-phenoxyl was reacted with tert.-butyl hydroperoxide (BHPO), cumene hydroperoxide (CHPO) and tri-phenylmethyl hydroperoxide (TPMHPO). Main reaction products are 2,4,6-tri-tert.-butyl phenol and substituted 4-cyclo-hexadienoneperoxides. Only by reacting TPMHPO a 2-cyclohexadienoneperoxide was isolated but by reacting BHPO and CHPO 3,5-di-tert.-butyl-o-quinone, isobutene and tert.-butanol or dimethylphenylcarbinole, resp., were formed. The products show the phenoxyradical attacking the peroxidic H-atom and a combination of formed peroxyradicals with phenoxyradicals. ESR-measurements demonstrate a first order radical decay, the reaction rate varies linear with hydroperoxide concentration. Hexaphenylethane (triphenylmethyl) reacts with BHPO under formation of triphenylmethylcarbinole, benzophenone, p-tert.-butoxy-triphenyl methane and little triphenylmethane. From these reaction products is to conclude that this radical attacks predominantly the peroxidic oxygen-oxygen bond.     

Bruchmechanische Überprüfung der Integrität des Primärkühlmittel-Eintrittsstutzens eines Druckwasser-Reaktordruckbehälters unter Zugrundelegung eines Kühlmittelverlust-Störfalles

Sicherheitstechnische Beurteilung eines Primärkühlmittel-Eintrittsstutzens mit Oberflächenrissen bei Eintritt eines Kühlmittelverlust-Störfalles. Voraussagen über kritische Rißgrößen während der Einspeisung von Kühlwasser. Bruchmechanische Berechnung unter Zugrundelegung des wahren Spannungsprofils sowie eines kontinuierlichen Umfangsrisses. Berücksichtigung der Bruchzähigkeit K_1c des Werkstoffes entsprechend dem Temperaturgradienten über die Wanddicke. Ermittlung von K_l-Faktoren mit Hilfe eines Computerprogrammes für verschiedene Stutzenquerschnitte in Abhängigkeit von der Rißtiefe und mit den für bestimmte Zeitintervalle erhaltenen Spannungsprofilen. Vergleich des Verlaufs der K-Faktoren mit dem Verlauf der Bruchzähigkeit.     

Rißwachstumsverhalten der austenitischen Stähle X 6 CrNi 18 11 und X 6 CrNiMo 1713 unter den Beanspruchungsbedingungen in natriumgekühlten Brutreaktoren

Mathematische Beschreibung des Rißwachstumsverhaltens der Stähle X 6 CrNi 18 11 mit rd. 0,06% C, 18% Cr und 11% Ni sowie X 6 CrNiMo17 13 mit rd. 0,06% C, 17% Cr, 2,5% Mo und 13% Ni an Luft bei Temperaturen bis 646°C und Lastspielfrequenzen von 8,3·10^?-2 bis 4 · 10³ Lastspielen/min. Einfluß von Carbidausscheidungen. Vergleich der Wirkung thermischer und schneller Neutronen. Frequenzabhängigkeit der Rißausbreitungsgeschwindigkeit. Verzögerte Rißausbreitung in der Umgebung von Schweißnähten. Rißwachstum unter Vakuum und in flüssigem Natrium zwischen 427 und 538°C.     

Linguistic intergroup bias: Differential expectancies or in-group protection?

The linguistic intergroup bias describes the tendency to communicate positive in-group and negative out-group behaviors more abstractly than negative in-group and positive out-group behaviors. This article investigated whether this bias is driven by differential expectancies or by in-group protective motives. In Exp 1, northern and southern Italian participants (N?=?151) described positive and negative behaviors of northern or southern protagonists that were either congruent or incongruent with stereotypic expectancies. Regardless of valence, expectancy-congruent behaviors were described more abstractly than incongruent ones. Exp 2 (N?=?40) showed that language is used in an equally biased fashion for individuals as previously demonstrated for groups. Exp 3 (N?=?192) induced expectancies experimentally and found greater abstraction for expectancy-congruent behaviors regardless of valence. All experiments confirmed the differential expectancy approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Einfluβ der hochtemperaturthermomechanischen Behandlung (HTMB) auf das Ausscheidungsverhalten und die mechanischen Eigenschaften des Martensits im unteren Anlaβtemperaturbereich

Untersuchung des Ausscheidungsverhaltens von hochtemperaturthermomechanisch und konventionell wärmebehandelten Stählen. Ermittlung von Korrelationen zwischen Ausscheidungsparametern und mechanischen Kenngröβen bei einachsiger Zugverformung in Abhängigkeit von der vorangegangenen Behandlung. Deutung der strukturellen Ursachen der Duktilitätssteigerung des niedrigangelassenen hochfesten Martensits durch HTMB.     

Experimental zones: two cases of exploring frames of participation in a dialogic museum

Abstract

A matter of concern for dialogic institutions such as museums is the struggle to find appropriate ways of integrating social media and digital technologies into dialogues with visitors. This paper addresses how co-creation and experimental methods may be applied in a situated, natural environment, exploring how these technologies may be shaped to support museum visitor relations. The concept ‘experimental zone’ is suggested as a format for a collaborative design space where digital media-based dialogues are explored in line with professional practices. This concept is discussed in relation to two design experiments undertaken in collaboration with the Norwegian Museum of Science and Technology.     

Matters of becoming,experimental zones for making museums public with social media

Making things public challenges existing matters of concern and, in design, may also be about changing them. This paper advances the concept of translation from early ANT literature and explores it in order to support co-designing for making things public. We elaborate on how translations may be understood as moves and transformations of practices and objects that require both time and learning. We discuss how translations may include the emerging, situated, fluid, enacted, experiential and the material, and suggest co-design to rethink translation as a temporal process of learning and ‘becoming’. Our aim is to demonstrate a mutual theoretical influence between ANT and co-design. Our conceptual reflection is based on a museum design case where museum staff and the authors explore new communicational modes of social media. The project established a longitudinal ‘experimental zone’ as space and time for design in the everyday practice of the museum. The paper reflects upon the value of ANT as a framework for rethinking the design–use divide using concepts of learning and translations to bring awareness of co-design as temporal, fluid and emerging processes of becoming.