Alcohol expectancies and reactivity to alcohol-related and affective cues.

Recent conceptualizations of alcohol expectancies relate cognitive schemas to their neurobiological underpinnings; cue reactivity paradigms lend themselves well to testing this broadened conceptual framework. In the present study, we examined the relationship between self-reported alcohol expectancies and responses to alcohol-related and affective picture cues among fifty-five young adults. In addition to traditional subjective and psychophysiological indices of cue reactivity, the startle eyeblink reflex was obtained during picture cue presentations to address both attention-arousal (early probes) and affective-motivational (late probes) aspects of cue processing. Analyses indicated that participants reporting greater positive, arousing, and social alcohol expectancies rated alcohol cues as more pleasant, arousing, and craving-inducing. In addition, participants displayed inhibited startle reactivity to late alcohol cue probes, indicative of an appetitive reaction. Finally, startle responding to early probes indicated that participants with greater alcohol expectancies displayed blunted attention to negative affect cues. Findings are discussed in terms of the utility of the startle reflex and cue reactivity paradigms for clarifying the relationship between alcohol expectancies and motivated attention to salient cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of dopants on alumina grain boundary sliding: implications for creep inhibition

We investigate by means of periodic density functional theory the mechanism of grain boundary sliding along the α-alumina Σ11 tilt grain boundary. We identify minimum and maximum energy structures along a preferential sliding pathway for the pure grain boundary, as well as for grain boundaries doped with a series of early transition metals, as well as barium, gadolinium, and neodymium. We predict that the segregation of those dopants results in a considerable increase in the grain boundary sliding barrier. Grain boundary sliding occurs by a series of bond breaking and forming across the grain boundary. Our results suggest that the presence of large cations inhibits the regeneration of bonds during sliding, which results in a decrease in total number of bonds across the grain boundary interface, thereby raising the barrier to sliding. Trends in predicted grain boundary sliding energies are in good agreement with recently measured creep activation energies in polycrystalline alumina, lending further credence to the notion that grain boundary sliding plays a dominant role in alumina creep.     

HIPed Tailored Hollandite Waste Forms for the Immobilization of Radioactive Cs and Sr

Hot isostatically pressed tailored hollandite waste forms were used to demonstrate the immobilization of Cs and Sr are separable from spent nuclear fuel, as well as Ba and Rb. Four hollandite formulations were investigated, two samples with ∼12 wt% waste loading (on an oxide basis) and two with ∼18 wt% waste loading. Two of the samples were Al-substituted and the other two contained Mg. The hollandite in the Al-substituted samples contained all the waste cations, as designed, but this was not the case in the Mg-substituted samples. The hollandite in the Mg-substituted samples did not contain all the waste cations, with ∼50% of the Sr forming SrTiO₃ as a secondary phase. This resulted in waste forms that were not as durable, with respect to Cs, as their Al counterparts. The formation of SrTiO₃ had little effect on the Sr release rates and was not detrimental to the Mg-substituted hollandite waste form. For the Al-substituted samples, the MCC-1 normalized release rates were <0.06 g·(m²·day)⁻¹ at 0–28 days for all elements, while the Cs release rates remained at 2.0 g·(m²·day)⁻¹ at 0–28 days for the Mg-substituted samples.     

Particulate matter chemical component concentrations and sources in settings of household solid fuel use

Particulate matter (PM) air pollution derives from combustion and non‐combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high‐income urban settings, which likely differ from the low‐ and middle‐income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real‐world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m^?3, 74.0 μg m^?3, and 155 ng m^?3, respectively. Solid fuel combustion explained 29%‐48% of principal component/factor analysis variance and 41%‐87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning.     

Efficient synchronisation signal for the switched satellite

An efficient synchronisation signal for the s.d.m.a./s.s-t.d.m.a. satellite is described, which achieves accurate synchronisation in one round-trip time, thus eliminating the need for repeated transmissions of synchronisation bursts. An added feature is the direct measurement of variations in path-length time delay, which may be used to track satellite motion.     

Dynamic mechanical properties of some polyurethane-acrylic copolymer interpenetrating polymer networks

Dynamic mechanical properties have been investigated for interpenetrating-network systems based on polyol-cured polyurethanes (PU) and 2 to 1 n-butyl acrylate-n-butyl methacrylate (Ac) networks. The systems were formed simultaneously (SIN) from all of the precursors and reactants for both networks in the same vessel, and sequentially (SIPN) by swelling a precured PU with the reactants that will form the Ac network. If the Ac network is formed after gelation of the PU, the IPNs are transparent and appear to have single T (tan δ_max) between those of the homonetworks; visible-phase separation occurs if the Ac is intentionally polymerized prior to PU gelation. Damping curves were lower and broader and the T (tan δ_max) and rubber moduli were higher for the SIN than for the SIPN systems. Up to 65 percent Ac, the T (tan δ_max) data for both SIN and SIPN fit the Gordon-Taylor equation if a T (tan δ_max) for the Ac homonetwork 7°C higher than observed is used, suggesting a higher crosslink density for the Ac network under these conditions. The differences in properties of the SIN and SIPN are assumed to be dependent on sample homogeneity and upon the presence of a tin catalyst in the SIN preparation. This can result in limited Ac-network formation and consequent phase separation before PU gelation has occurred, and the catalyst may also increase the extent of interaction, such as grafting or hydrogen-bond formation between the networks.     

Echium oil is better than rapeseed oil in improving the response of barramundi to a disease challenge

Pathogen infection stimulates the fatty acid (FA) metabolism and the production of pro-inflammatory derivatives of FA. Barramundi, Lates calcarifer, was fed on a diet rich in preformed long-chain (?C₂₀) polyunsaturated fatty acids (LC-PUFA) from fish oil (FO), to compare with diets containing high levels of C₁₈ precursors for LC-PUFA – stearidonic (SDA) and γ-linolenic acid (GLA) – from Echium plantagineum (EO), or rapeseed oil (RO) rich in α-linolenic acid (ALA), but a poor source of LC-PUFA and their precursors. After 6 weeks, when growth rates were similar amongst the dietary treatments, a sub-lethal dose of Streptococcus iniae was administered to half of the fish, while the other half were maintained unchallenged and were pair-fed with the infected fish. Under a disease challenge situation, the tissue FA depots depleted at 3 days post-infection (DPI) and were then restored to their previous concentrations at 7 DPI. During the infection period, EO fish had a higher content of n3 and n6 PUFA in their tissues, higher n3:n6 PUFA ratio and reduced levels of the eicosanoids, TXB₂ and 6-keto-PGF_1α, in their plasma compared with RO fish. Fish fed on FO and EO had a longer lasting and enduring response in their FA and eicosanoid concentrations, following a week of bacterial infection, compared with those fed on RO. EO, containing SDA and GLA and with a comparatively higher n3:n6 PUFA ratio, proved more effective than RO in compensating for immunity stress.     

Effect of barrier width on performance of long wavelengthGaInAs/InP multi-quantum-well lasers

It is demonstrated that lasing thresholds in GaInAs/InP MQW lasers under electrical injection are sensitive to the InP barrier thickness and that reducing the barrier width contributes significantly to achieving low-threshold, room temperature operation. In contrast, lasing thresholds under optical pumping show a relative insensitivity to the barrier width. The authors show that this behaviour is consistent with preferential hole capture in the leading wells     

Pattern formation in chick feather development: distribution of beta 1-integrin in normal and scaleless embryos

We have examined the immunolocalization of beta 1-integrin during feather development in the spino-lumbar tract of the backskin from normal and scaleless chick embryos. beta 1-integrin appears during early feather development in three distinct phases which correspond to important developmental events. The first phase (5-5 1/2 days of incubation; Hamburger and Hamilton [H.H.] stage 27) represents the period prior to the formation of dermis. During this phase, beta 1-integrin antiserum labels mesenchymal cells located in the central region of the spino-lumbar tract where the initiation site for feather development is located. The second phase (5 1/2-7 1/2 days of incubation; H.H. stages 28-32) corresponds to the period during which dermis is formed. The cells that make up the dermis are readily distinguished by their lack of beta 1-integrin immunostaining. The third phase (7 1/2-10 days of incubation; H.H. stages 33-36) begins with the sudden appearance of beta 1-integrin in the central and lateral regions of the dermis. The pattern of beta 1-integrin immunostaining in scaleless backskin becomes different from that of normal backskin during this phase. In normal backskin the dermal condensations of feather germs are not labeled with the beta 1-integrin antiserum. This produces a heterogeneous immunostaining pattern very similar to the pattern seen for Type I collagen (Mauger et al. [1982] Dev. Biol. 94:93-105). In contrast, homogeneous immunostaining is observed in the dermis of scaleless backskin. The initial time of appearance, manner of appearance, and pattern of integrin expression in the third phase suggest that beta 1-integrin may be involved in the stabilization of the feather pattern. We also observed the appearance of beta 1-integrin on the epidermal basal cells during the time of feather follicle formation. The beta 1-integrin antiserum reacts strongly with the baso-lateral surfaces of normal basal cells, yet the basal surfaces of the scaleless basal cells are unstained. This lack of immunostaining along the basal surfaces of the scaleless basal cells may relate to the abnormal adhesion between the epidermis and dermis in scaleless backskin.     

Attentional effects of single dose triazolam

1. While the effects of benzodiazepines on human memory have been extensively studied little is known about the effects of these agents on attentional processes. The authors studied the effects of a single dose of triazolam on selective visual-spatial attention using a double blind, placebo controlled design. 2. In each of 2 sessions 12 normal volunteers ingested either 0.25 mg of triazolam or placebo. Attentional performance was evaluated using two versions of the covert orienting paradigm which measured automatic (exogenous) and controlled (endogenous) aspects of attentional orienting, respectively. 3. Triazolam selectively modified performance on automatic orienting to exogenous cues. Specifically, triazolam increased the facilitation of target detection seen at shorter (150 msec) SOA's. This may indicate an increase in facilitation and a reduction in inhibition or a slowing of the time course of the biphasic attentional effect normally resulting from exogenous cuing. 4. These results indicate the importance of using experimental paradigms which effectively dissociate endogenous and exogenous mechanisms of spatial orienting in studies evaluating the effects of pharmacological agents on visual-spatial attention.