91 research outputs found

    Conjugation with L, L-diphenylalanine Self-Assemblies Enhances In Vitro Antitumor Activity of Phthalocyanine Photosensitizer

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    We present the synthesis and characterization of new peptide conjugates obtained by hierarchical co-assembly of L,L-diphenylalanine (FF) and zinc phthalocyanine complexes (ZnPc) in water. Self-assembly capabilities under defined conditions were investigated by scanning electron microscopy, and photophysical properties were evaluated using UV-Vis and fluorescence spectroscopy. AFM observations demonstrated that these ZnPcs form different highly ordered arrays on the crystalline faces of the FF microplates and that surface roughness significantly changes with the presence of differently substituted phthalocyanine units. XRD assays showed that the overall molecular packing of the conjugates is organized according to a hexagonal symmetry, with ZnPcs hosted in the interstices of the peptide phase. In vitro photodynamic studies were conducted on human breast cancer MCF-7 cells to investigate both cellular uptake and cytotoxicity. It was shown that FF self-assemblies are not toxicity and enhance accumulation of ZnPc in MCF-7 cells, improving apoptotic cell death upon irradiation. Our findings demonstrate enhancement of ZnPc antitumor efficiency by FF conjugates and a proof-of-concept for new photosensitizer carriers based on peptide conjugates

    Zygosity diagnosis in young twins by parental report

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    this paper is twofold. First, the validity of zygosity classification across childhood is examined in a large sample. One might expect the physical dissimilarity between dizygotic twins to become more obvious as they grow up. If so, the accuracy of classification is likely to improve with increasing age of the participants. A few studies have reported on this issue by evaluating the precision of zygosity diagnosis between samples varying in age, 8,19,23 and by test--retest estimatio

    Mechanisms Underlying Stage-1 TRPL Channel Translocation in Drosophila Photoreceptors

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    Background: TRP channels function as key mediators of sensory transduction and other cellular signaling pathways. In Drosophila, TRP and TRPL are the light-activated channels in photoreceptors. While TRP is statically localized in the signaling compartment of the cell (the rhabdomere), TRPL localization is regulated by light. TRPL channels translocate out of the rhabdomere in two distinct stages, returning to the rhabdomere with dark-incubation. Translocation of TRPL channels regulates their availability, and thereby the gain of the signal. Little, however, is known about the mechanisms underlying this trafficking of TRPL channels. Methodology/Principal Findings: We first examine the involvement of de novo protein synthesis in TRPL translocation. We feed flies cycloheximide, verify inhibition of protein synthesis, and test for TRPL translocation in photoreceptors. We find that protein synthesis is not involved in either stage of TRPL translocation out of the rhabdomere, but that re-localization to the rhabdomere from stage-1, but not stage-2, depends on protein synthesis. We also characterize an ex vivo eye preparation that is amenable to biochemical and genetic manipulation. We use this preparation to examine mechanisms of stage-1 TRPL translocation. We find that stage-1 translocation is: induced with ATP depletion, unaltered with perturbation of the actin cytoskeleton or inhibition of endocytosis, and slowed with increased membrane sterol content. Conclusions/Significance: Our results indicate that translocation of TRPL out of the rhabdomere is likely due to protei

    Heat treatment of cold-sprayed C355 Al for repair: microstructure and mechanical properties

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    Cold gas dynamic spraying of commercially pure aluminum is widely used for dimensional repair in the aerospace sector as it is capable of producing oxide-free deposits of hundreds of micrometer thickness with strong bonding to the substrate, based on adhesive pull-off tests, and often with enhanced hardness compared to the powder prior to spraying. There is significant interest in extending this application to structural, load-bearing repairs. Particularly, in the case of high-strength aluminum alloys, cold spray deposits can exhibit high levels of porosity and microcracks, leading to mechanical properties that are inadequate for most load-bearing applications. Here, heat treatment was investigated as a potential means of improving the properties of cold-sprayed coatings from Al alloy C355. Coatings produced with process conditions of 500 °C and 60 bar were heat-treated at 175, 200, 225, 250 °C for 4 h in air, and the evolution of the microstructure and microhardness was analyzed. Heat treatment at 225 and 250 °C revealed a decreased porosity (~ 0.14% and 0.02%, respectively) with the former yielding slightly reduced hardness (105 versus 130 HV0.05 as-sprayed). Compressive residual stress levels were approximately halved at all depths into the coating after heat treatment, and tensile testing showed an improvement in ductility

    Genetic Epidemiology of Attention Deficit Hyperactivity Disorder (ADHD Index) in Adults

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    Context: In contrast to the large number of studies in children, there is little information on the contribution of genetic factors to Attention Deficit Hyperactivity Disorder (ADHD) in adults. Objective: To estimate the heritability of ADHD in adults as assessed by the ADHD index scored from the CAARS (Conners’ Adult ADHD Rating Scales). Design: Phenotype data from over 12,000 adults (twins, siblings and parents) registered with the Netherlands Twin Register were analyzed using genetic structural equation modeling. Main outcome measures: Heritability estimates for ADHD from the twin-family study. Results: Heritability of ADHD in adults is estimated around 30 % in men and women. There is some evidence for assortative mating. All familial transmission is explained by genetic inheritance, there is no support for the hypothesis that cultural transmission from parents to offspring is important. Conclusion: Heritability for ADHD features in adults is present, but is substantially lower than it is in children

    The Rotterdam Study: objectives and design update

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    The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods

    Genetic and Environmental Causes of Variation in Trait Resilience in Young People

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    The aim of this multi-informant twin study was to determine the relative role of genetic and environmental factors in explaining variation in trait resilience in adolescents. Participants were consenting families (N = 2,638 twins in 1,394 families), from seven national cohorts (age 12–18 years, both sexes) of monozygotic and dizygotic twins reared together. Questionnaire data on the adolescents’ Ego-resilience (ER89) was collected from mothers, fathers and twins, and analysed by means of multivariate genetic modelling. Variance in trait resilience was best represented in an ADE common pathways model with sex limitation. Variance in the latent psychometric resilience factor was largely explained by additive genetic factors (77% in boys, 70% in girls), with the remaining variance (23 and 30%) attributable to non-shared environmental factors. Additive genetic sources explained more than 50% of the informant specific variation in mothers and fathers scores. In twins, additive and non-additive genetic factors together explained 40% and non-shared environmental factor the remaining 60% of variation. In the mothers’ scores, the additive genetic effect was larger for boys than for girls. The non-additive genetic factor found in the twins’ self ratings was larger in boys than in girls. The remaining sex differences in the specific factors were small. Trait resilience is largely genetically determined. Estimates based on several informants rather than single informants approaches are recommended

    The sleep EEG spectrum is a sexually dimorphic marker of general intelligence

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    The shape of the EEG spectrum in sleep relies on genetic and anatomical factors and forms an individual “EEG fingerprint”. Spectral components of EEG were shown to be connected to mental ability both in sleep and wakefulness. EEG sleep spindle correlates of intelligence, however, exhibit a sexual dimorphism, with a more pronounced association to intelligence in females than males. In a sample of 151 healthy individuals, we investigated how intelligence is related to spectral components of full-night sleep EEG, while controlling for the effects of age. A positive linear association between intelligence and REM anterior beta power was found in females but not males. Transient, spindle-like “REM beta tufts” are described in the EEG of healthy subjects, which may reflect the functioning of a recently described cingular-prefrontal emotion and motor regulation network. REM sleep frontal high delta power was a negative correlate of intelligence. NREM alpha and sigma spectral power correlations with intelligence did not unequivocally remain significant after multiple comparisons correction, but exhibited a similar sexual dimorphism. These results suggest that the neural oscillatory correlates of intelligence in sleep are sexually dimorphic, and they are not restricted to either sleep spindles or NREM sleep
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