Device Applications of Side-Chain Ferroelectric Liquid Crystalline Polymer Films

Side-chain ferroelectric liquid crystalline polymers are currently used in a number of applications, including displays and electrical sensors. Comparisons with existing technologies and materials indicate that relative to ceramics, such polymers have lower figures of merit but offer greater durability in sensor applications.     

Molecular and neuronal substrate for the selective attenuation of anxiety

Benzodiazepine tranquilizers are used in the treatment of anxiety disorders. To identify the molecular and neuronal target mediating the anxiolytic action of benzodiazepines, we generated and analyzed two mouse lines in which the alpha2 or alpha3 GABAA (gamma-aminobutyric acid type A) receptors, respectively, were rendered insensitive to diazepam by a knock-in point mutation. The anxiolytic action of diazepam was absent in mice with the alpha2(H101R) point mutation but present in mice with the alpha3(H126R) point mutation. These findings indicate that the anxiolytic effect of benzodiazepine drugs is mediated by alpha2 GABAA receptors, which are largely expressed in the limbic system, but not by alpha3 GABAA receptors, which predominate in the reticular activating system.     

Functional links between Aβ toxicity, endocytic trafficking, and Alzheimer's disease risk factors in yeast

Aβ (beta-amyloid peptide) is an important contributor to Alzheimer's disease (AD). We modeled Aβ toxicity in yeast by directing the peptide to the secretory pathway. A genome-wide screen for toxicity modifiers identified the yeast homolog of phosphatidylinositol binding clathrin assembly protein (PICALM) and other endocytic factors connected to AD whose relationship to Aβ was previously unknown. The factors identified in yeast modified Aβ toxicity in glutamatergic neurons of Caenorhabditis elegans and in primary rat cortical neurons. In yeast, Aβ impaired the endocytic trafficking of a plasma membrane receptor, which was ameliorated by endocytic pathway factors identified in the yeast screen. Thus, links between Aβ, endocytosis, and human AD risk factors can be ascertained with yeast as a model system.     

A review of the economic and ecological constraints on animal draft cultivation in sub-Saharan Africa

With a limited number of cash cropping areas, sub-Saharan Africa has the lowest level of mechanization including animal-driven implements and use of tractors. In this paper previous research is reviewed to evaluate the economic and ecological constraints to animal draft cultivation.

Results of past studies have shown that the animal-drawn plow is only profitable at higher intensities of farming induced by population growth and better market access. Utilization and use of animal-driven implements will, however, be low in areas characterized by light soils (arid zones) or areas prone to erosion, or with a short growing season.

Other constraints on the profitable use of animal draft are farmers' characteristics and policy factors. Farm and family size, the farmer's experience and types of equipment are shown to play important roles. One factor often ignored is the opportunity cost of labor and capital during off-farm activities. Utilization of animal traction implies tending costs. If, however, the cost of maintaining the animal outside the peak season reduces off-farm income opportunities, farmers are not likely to make a profitable use of the plow. Other opportunities available to the farmer (e.g. beef production when beef prices are high) are likely to have a negative impact on utilization of oxen cultivation. Rural-urban dualism which characterizes African agriculture owing to low agricultural productivity and high wages in cities, is likely to be an important constraint.     

Conversion of α-pinene to α-pinene oxide by rat liver and the bark beetle Dendroctonus terebrans microsomal fractions

The metabolism of α-pinene, a major monoterpene in Pinus spp. in the United States, has been examined utilizing microsomal fractions from larval and adult Dendroctonus terebrans and rat liver. Under hydroxylating conditions, both insect and rat liver microsomes convert α-pinene into α-pinene oxide and several other undentified products. α-Pinene oxide was identified by mass spectrometry. α-Pinene is an inducer of cytochrome P-450 in rat liver microsomes and its effect on the pattern of α-pinene metabolism is very similar to β-naphthoflavone. No increase in cytochrome P-450 was observed when insects were treated with α-pinene; however, the quantity of α-pinene metabolic products was increased by α-pinene pretreatment. The role of cytochrome P-450 linked reactions in the production of insect pheromones via the α-pinene epoxide intermediate is discussed.