New Bioactive Oxylipins Formed by Non-Enzymatic Free-Radical-Catalyzed Pathways: the Phytoprostanes

In animals and plants, fatty acids with at least three double bonds can be oxidized to prostaglandin-like compounds via enzymatic and non-enzymatic pathways. The most common fatty acid precursor in mammals is arachidonic acid (C20:4) (AA) which can be converted through the cyclooxygenase pathway to a series of prostaglandins (PG). Non-enzymatic cyclization of arachidonate yields a series of isoprostanes (IsoP) which comprises all PG (minor compounds) as well as PG isomers that cannot be formed enzymatically. In contrast, in plants, α-linolenic acid (C18:3) (ALA) is the most common substrate for the allene oxide synthase pathway leading to the jasmonate (JA) family of lipid mediators. Non-enzymatic oxidation of linolenate leads to a series of C18-IsoPs termed dinor IsoP or phytoprostanes (PP). PP structurally resemble JA but cannot be formed enzymatically. We will give an overview of the biological activity of the different classes of PP and also discuss their analytical applications and the strategies developed so far for the total synthesis of PP, depending on the synthetic approaches according to the targets and which key steps serve to access the natural products.     

Woodlands equipment maintenance: An analysis of mechanical labor energy expenditure

The accident frequency rate of forestry field mechanics is eight times the industry average. A contributing factor is physical fatigue caused by energy-demanding tasks, difficult working positions, and hostile environmental conditions.

the heart rate/oxygen uptake method was used to determine human energy expenditure levels for eight specific maintenance activities. Eight work positions were also identified, and their energy expenditure levels were recorded.

Mean daily shift-level energy expenditures were found to be in excess of 10,000 kJ, equivalent to a continuous average output above 20.0 kJ per minute. The most energy-demanding task was removing engine protection plates. The most energy-demanding position was standing, with the body bent forward at the waist, over some obstacle.

It is concluded that maintenance mechanics routinely work at 33% of their predicted maximal oxygen uptake level, a value that is considered to be at the top of the acceptable range for physically active male workers. At this level, the potential for an accident situation is high.     

Computational aspects of the workload distribution in the MMPP/GI/1queue

We show how the analysis of Markov modulated rate processes can be used to address the problem of computing the distribution of W, the stationary workload in the MMPP/GI/1 queue. Using the results of papers by Anick et al. (1982); Mitra (1988); and Elwalid et al. (1991), we present the decomposition properties of the Laplace transform of W and efficient computational algorithms for computing its distribution. The techniques are also applied to compute the bounds on the distribution of W developed by Liu et al. (see JACM, vol.44, no.2, p.366-94, 1997). Numerical results illustrating the usefulness of the methods are given for the case of the superposition of independent, nonidentical sources     

HPLC analysis of quaternary ammonium surfactants with the evaporative light scattering detector

A normal-phase high-pressure liquid chromatography technique has been elaborated for the separation of quaternary ammonium surfactants. The separation was achieved on a bonded polyphenol silica gel column with gradient elution and evaporative light-scattering (ELS) detection. The proposed method has been applied to the quantitative determination of low levels of monoalkyltrimethylammonium and trialkylmethylammonium chlorides in dialkyldimethylammonium chloride.     

Le pouvoir conjugal et l'évitement des conflits chez les hommes.

Three hypotheses have been advanced to explain sex differences in withdraw behavior during conflictual marital interactions: the greater physiological reactivity of men during conflict situations, the differential socialization of men and women, and the differential power assigned to men and women. The main objective of this study was to examine the hypothesis that marital power is a good predictor of husbands' withdrawal. 132 couples completed a series of questionnaires, including the Marital Adjustment Test, a communication questionnaire, and 2 measures of marital power. Results show that marital adjustment predicted 44% of husbands' withdrawal, while marital power did not account for a significant proportion of the variance. These results are discussed in the light of the suggested hypotheses accounting for the differences in husbands and wives behavior during marital conflict. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural study by 1H NMR of the first adducts of the telomerization of methylmethacrylate with thiophenol

The stereoselectivity of the different steps (addition step and transfer step) of the radical telomerization of methylmethacrylate with thiophenol has been determined by preparing and analyzing the first adducts by ¹H NMR analysis.     

Understanding the copper of the Statue of Liberty

Pierre-Eugène Secrétan, a French copper industrialist, donated the copper sheets for the construction of the skin of the Statue of Liberty when it was built in 1875–1876. It can be inferred from the history of Secrétan's activities that the sheets were rolled in his plant of Sérifontaine. The impurities found in two samples obtained from the U.S. National Park Service show that different qualities of copper were used. They indicate, by taking also into account the commercial relations of Secrétan, that the copper may possibly have come from Spanish or South/North American ore.     

Measurement of the longitudinal and transverse diffusion of single electrons drifting in gases

The transit time of single drifting electrons has been measured in several gases, over distances ranging from 5 cm up to 80 cm. The longitudinal diffusion coefficient is deduced from the fluctuations of this transit time. The transverse diffusion has been measured directly by scanning the electron impact density at the end of the drift zone. The effect of a longitudinal magnetic field has also been studied.