Prefrontal cortex and caudate nucleus in conditional associative learning: Dissociated effects of selective brain lesions in rats.

Rats with lesions to prefrontal cortex (PFC) or caudate nucleus (CN) were compared on tests of conditional associative learning (CAL) that placed varying demands on conditional rule learning and working-with-memory operations that are essential for response selection. Damage to either structure impaired performance, but the respective deficits resulted from disruption of different processes. CN lesions produced a consistent learning deficit that was thought to reflect a basic impairment in forming stimulus-response (S-R) associations. The behavior of PFC rats was more variable and depended on task requirements. When S-R learning or response selection was relatively easy, the PFC was not critical. However, when either component was made more difficult, thus requiring the contribution of strategic processes, PFC damage produced profound impairments. In addition to clarifying the roles of the PFC and CN in CAL, the results provide further evidence that multiple brain regions participate in relatively simple behavioral tasks and that their respective contributions can be dissociated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and biological activities of phenyl piperazine-based peptidomimetic growth hormone secretagogues

A new class of potent, orally active phenyl piperazine-based GH secretagogues have been discovered from attempts to mimic the arrangement of the phenyl substituent in the spiroindanyl piperidine and spiroindoline sulfonamide privileged structures of 4 and 1, respectively. The best of these compounds, 18 (EC50 = 2.8 nM) is nearly as potent as MK-0677 for releasing GH from rat pituitary cells.     

Optically pumped submillimeter gas lasers and the prospects for constructing space-qualifiable LO systems

An optically pumped submillimeter laser operating in the 500 μm (600 GHz) to 100 μm (3 THz) spectral range is the primary and, at present, the only available local oscillator (LO) source for laboratory and astronomical heterodyne applications for this wavelength region. A short review of the state-of-the-art of submillimeter lasers as LO sources, with an emphasis given to receiver systems designed for airborne heterodyne observations, will be presented. The characteristics and prospects for constructing a spacequalifiable laser LO system will also be given.     

Corrosion of Fe-10Al-Cr alloys by coal char

Corrosion of iron-base alloys at 982°C (1800°F) by coal char is observed and the phase morphologies are discussed. No sulfidation was observed at 50 hr exposure. After 100 hr internal aluminum-rich sulfides were observed along with thick outer scales of iron oxide. The species causing the hightemperature-induced corrosion are probably sulfides and sulfates, present in most coal chars. Possible mechanisms for the corrosion are also discussed.Department of Materials Science and Mineral Engineering.     

Mechanical properties of certain oriented crystalline polymers

The yield stress is a simple function of the deformation ratio in the direction of testing for specimens oriented by uniaxial or biaxial stretching or rolling. Unless the yield stress increases more rapidly than in proportion to the deformation ratio, there will be instability during tensile creep under high loads. The relative merit of various polymers differs for creep and stress relaxation. Fatigue and bend recovery are also related to the molecular structure.     

Non-Isothermal crystallization of isotactic polypropylene in dotriacontane. I: Effects of dilution,cooling rate,and nucleating agent addition on overall crystallization kinetics

The overall non-isothermal crystallization kinetics for nucleated and non-nucleated isotactic polypropylene (iPP) in dotriacontane systems was investigated. Adipic acid was used as the nucleating agent. Crystallization peak temperature was determined via differential scanning calorimetry as a function of the experimentally controlled variables iPP concentration, cooling rate, and nucleating agent concentration. The influence of these variables on crystallization mechanism and spherulitic structure as implied by the Ozawa and Ziabicki analyses was determined. The non-isothermal crystallization kinetics presented here are the first for iPP-diluent systems with and without nucleating agent.     

Inactivation of Giardia muris Using Ozone and Ozone-Hydrogen Peroxide

The disinfection effects of the ozone molecule alone and that of ozone decomposition products when inactivating Giardia muris cysts were investigated at bench-scale using two different ozone demand-free laboratory buffer systems. The first water was a 0.05 M phosphate buffer with hydrogen peroxide added at a 10:1 weight ratio. The second water was a 0.05 M phosphate – 0.01 M bicarbonate buffer which quickly scavenged radical species from ozone decomposition. The C3H/HeN mouse model was used to assess the infectivity of ozone treated cysts.

The phosphate-bicarbonate buffer system had significantly greater (P ≤ 0.05) inactivation of G. muris cysts than that observed in the phosphate buffer – peroxide system where ozone was completely decomposed in less than 120 s. Consequently, the design of ozone disinfection processes should maintain ozone residual for disinfection prior to the addition of hydrogen peroxide for the oxidation of other compounds.     

Polymer modification and synthesis using sulphenyl derivatives: 9. Addition of alkylsulphenyl chlorides to cis-1, 4-polybutadiene

Methanesulphenyl chloride and n-butanesulphenyl chloride add readily across the double bonds in cis-1,4-polybutadiene. The addition is highly regioselective so that long sequences of saturated units are formed. The products are very unstable, evolving hydrogen chloride on standing, but can be stabilized by replacing the labile chlorine atom with other nucleophiles in a phase transfer catalysed reaction.     

Sub-ambient cold-start emissions reduction using SwRI® PO x catalyst technology

This paper describes the application of SwRI’s cold-start PO _x catalyst technology to reduce cold-start hydrocarbon emissions from a US Tier 2 vehicle at −7 °C. A reduction in −7 °C (20 °F) cold-start hydrocarbons will help US Tier 2 vehicles meet the proposed EPA NMOG standards. Improvements in cold temperature hydrocarbon emissions would also be beneficial in many parts of Europe during the winter months. In this work, a total hydrocarbon reduction of 19% was realized at 24 °C, in line with previous results, but only up to 3% at −7 °C. Insufficient oxygen in the engine-out exhaust gas at −7 °C was determined to be the reason why the PO _x catalyst failed to significantly reduce HC emissions. Addition of supplemental oxygen to the exhaust during the cold-start, to simulate an adjustment in the engine calibration to less rich operation, resulted in a total hydrocarbon reduction of 18% with the PO _x catalysts in place, but no benefit when the PO _x catalysts were removed. Hence, the PO _x catalyst approach can be used to good effect, even under sub-ambient cold-start conditions.     

Feeding response of Ips paraconfusus to phloem and phloem metabolites of Heterobasidion annosum-inoculated ponderosa pine,Pinus ponderosa

In studies of feeding by the bark beetle, Ips paraconfusus, two pine stilbenes (pinosylvin and pinosylvin methyl ether), ferulic acid glucoside, and enantiomers of the four most common sugars present in ponderosa pine phloem (sucrose, glucose, fructose, and raffinose) did not stimulate or reduce male feeding when assayed on wet -cellulose with or without stimulatory phloem extractives present. When allowed to feed on wet -cellulose containing sequential extracts (hexane, methanol, and water) of ponderosa pine phloem, methanol and water extractives stimulated feeding, but hexane extractives did not. Males confined in wet -cellulose containing aqueous or organic extracts of culture broths derived from phloem tissue and containing the root pathogen, Heterobasidion annosum, ingested less substrate than beetles confined to control preparations. In an assay using logs from uninoculated ponderosa pines, the mean lengths of phloem in the digestive tracts increased as time spent feeding increased. Males confined to the phloem of basal logs cut from ponderosa pines artificially inoculated with H. annosum ingested significantly less phloem than beetles in logs cut from trees that were (combined) mock-inoculated or uninoculated and did not contain the pathogen. However, individual pathogen-containing treatments were not significantly different from uninoculated controls. It was concluded that altered feeding rates are not a major factor which may explain why diseased ponderosa pines are colonized by I. paraconfusus.