354 research outputs found

    Event related potentials reveal that increasing perceptual load leads to increased responses for target stimuli and decreased responses for irrelevant stimuli

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    This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.Peer reviewedPublisher PD

    Poly (glycerol adipate) (PGA), an enzymatically synthesized functionalizable polyester and versatile drug delivery carrier : A literature update

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    The enzymatically synthesized poly (glycerol adipate) (PGA) has demonstrated all the desirable key properties required from a performing biomaterial to be considered a versatile "polymeric-tool" in the broad field of drug delivery. The step-growth polymerization pathway catalyzed by lipase generates a highly functionalizable platform while avoiding tedious steps of protection and deprotection. Synthesis requires only minor purification steps and uses cheap and readily available reagents. The final polymeric material is biodegradable, biocompatible and intrinsically amphiphilic, with a good propensity to self-assemble into nanoparticles (NPs). The free hydroxyl group lends itself to a variety of chemical derivatizations via simple reaction pathways which alter its physico-chemical properties with a possibility to generate an endless number of possible active macromolecules. The present work aims to summarize the available literature about PGA synthesis, architecture alterations, chemical modifications and its application in drug and gene delivery as a versatile carrier. Following on from this, the evolution of the concept of enzymatically-degradable PGA-drug conjugation has been explored, reporting recent examples in the literature.Peer reviewedFinal Published versio

    A novel non-Fermi-liquid state in the iron-pnictide FeCrAs

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    We report transport and thermodynamic properties of stoichiometric single crystals of the hexagonal iron-pnictide FeCrAs. The in-plane resistivity shows an unusual "non-metallic" dependence on temperature T, rising continuously with decreasing T from ~ 800 K to below 100 mK. The c-axis resistivity is similar, except for a sharp drop upon entry into an antiferromagnetic state at T_N 125 K. Below 10 K the resistivity follows a non-Fermi-liquid power law, rho(T) = rho_0 - AT^x with x<1, while the specific heat shows Fermi liquid behaviour with a large Sommerfeld coefficient, gamma ~ 30 mJ/mol K^2. The high temperature properties are reminiscent of those of the parent compounds of the new layered iron-pnictide superconductors, however the T -> 0 properties suggest a new class of non-Fermi liquid.Comment: 6 pages, 4 figure

    From soft harmonic phonons to fast relaxational dynamics in CH3_{3}NH3_{3}PbBr3_{3}

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    The lead-halide perovskites, including CH3_{3}NH3_{3}PbBr3_{3}, are components in cost effective, highly efficient photovoltaics, where the interactions of the molecular cations with the inorganic framework are suggested to influence the electronic and ferroelectric properties. CH3_{3}NH3_{3}PbBr3_{3} undergoes a series of structural transitions associated with orientational order of the CH3_{3}NH3_{3} (MA) molecular cation and tilting of the PbBr3_{3} host framework. We apply high-resolution neutron scattering to study the soft harmonic phonons associated with these transitions, and find a strong coupling between the PbBr3_{3} framework and the quasistatic CH3_{3}NH3_{3} dynamics at low energy transfers. At higher energy transfers, we observe a PbBr6_{6} octahedra soft mode driving a transition at 150 K from bound molecular excitations at low temperatures to relatively fast relaxational excitations that extend up to \sim 50-100 meV. We suggest that these temporally overdamped dynamics enables possible indirect band gap processes in these materials that are related to the enhanced photovoltaic properties.Comment: (main text - 5 pages, 4 figures; supplementary information - 3 pages, 3 figures

    Task cues lead to item-level backward inhibition with univalent stimuli and responses

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    Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.Peer reviewedPostprin

    Direct relation between the low-energy spin excitations and superconductivity of overdoped high-TcT_c superconductors

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    The dynamic spin susceptibility, χ(ω)\chi''(\omega), has been measured over the energy range of 2ω102 \leq \omega \leq 10 meV for overdoped La2x_{2-x}Srx_{x}CuO4_{4}. Incommensurate (IC) spin excitations are observed at 8 K for all superconducting samples for 0.25x0.280.25 \leq x \leq 0.28 with χ\chi'' peaking at 6\sim 6 meV. The IC peaks at 6 meV become smaller in intensity with increasing xx and, finally, become unobservable for a sample with x=0.30x=0.30 which has no bulk superconductivity. The maximum χ\chi'' decreases linearly with TcT_c(onset) in the overdoped region, implying a direct cooperative relation between the spin fluctuations and the superconductivity.Comment: 4 pages, 4 figure

    Bread and roses, shelter and community : psychological sense of community for single mothers in housing

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    vi, 61 leaves : ill. ; 28 cm.Includes bibliographical references (leaves 53-61).The relationship between empowerment and sense of community was explored by investigating how they are related to the degree of self-management and problem-solving available in different forms of housing. One hundred and one single mothers from public housing, co-op housing, and private rental units completed the Sense of Community Index (SCI) the Personal Power (PP) Scale, and the Masculinity Scale of the Bem Sex Role Inventory. Analysis of covariance indicated sense of community was significantly higher for co-op residents even when education levels, age, income, length of residency, expected length of residency and level of participation in neighbourhood organizations were controlled statistically. Implications for development of housing forms that facilitate sense of community are discussed

    Prediction of whole-body fat percentage and visceral adipose tissue mass from five anthropometric variables

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    Background The conventional measurement of obesity utilises the body mass index (BMI) criterion. Although there are benefits to this method, there is concern that not all individuals at risk of obesity-associated medical conditions are being identified. Whole-body fat percentage (%FM), and specifically visceral adipose tissue (VAT) mass, are correlated with and potentially implicated in disease trajectories, but are not fully accounted for through BMI evaluation. The aims of this study were (a) to compare five anthropometric predictors of %FM and VAT mass, and (b) to explore new cut-points for the best of these predictors to improve the characterisation of obesity. Methods BMI, waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and waist/height0.5 (WHT.5R) were measured and calculated for 81 adults (40 women, 41 men; mean (SD) age: 38.4 (17.5) years; 94% Caucasian). Total body dual energy X-ray absorptiometry with Corescan (GE Lunar iDXA, Encore version 15.0) was also performed to quantify %FM and VAT mass. Linear regression analysis, stratified by sex, was applied to predict both %FM and VAT mass for each anthropometric variable. Within each sex, we used information theoretic methods (Akaike Information Criterion; AIC) to compare models. For the best anthropometric predictor, we derived tentative cut-points for classifying individuals as obese (>25% FM for men or >35% FM for women, or > highest tertile for VAT mass). Results The best predictor of both %FM and VAT mass in men and women was WHtR. Derived cut-points for predicting whole body obesity were 0.53 in men and 0.54 in women. The cut-point for predicting visceral obesity was 0.59 in both sexes. Conclusions In the absence of more objective measures of central obesity and adiposity, WHtR is a suitable proxy measure in both women and men. The proposed DXA-%FM and VAT mass cut-offs require validation in larger studies, but offer potential for improvement of obesity characterisation and the identification of individuals who would most benefit from therapeutic intervention

    Techniques in Analytic Lamb Shift Calculations

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    Quantum electrodynamics has been the first theory to emerge from the ideas of regularization and renormalization, and the coupling of the fermions to the virtual excitations of the electromagnetic field. Today, bound-state quantum electrodynamics provides us with accurate theoretical predictions for the transition energies relevant to simple atomic systems, and steady theoretical progress relies on advances in calculational techniques, as well as numerical algorithms. In this brief review, we discuss one particular aspect connected with the recent progress: the evaluation of relativistic corrections to the one-loop bound-state self-energy in a hydrogenlike ion of low nuclear charge number, for excited non-S states, up to the order of alpha (Zalpha)^6 in units of the electron mass. A few details of calculations formerly reported in the literature are discussed, and results for 6F, 7F, 6G and 7G states are given.Comment: 16 pages, LaTe
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