373 research outputs found

    Iron deficiency reduces synapse formation in the Drosophila clock circuit

    Get PDF
    Iron serves as a critical cofactor for proteins involved in a host of biological processes. In most animals, dietary iron is absorbed in enterocytes and then disseminated for use in other tissues in the body. The brain is particularly dependent on iron. Altered iron status correlates with disorders ranging from cognitive dysfunction to disruptions in circadian activity. The exact role iron plays in producing these neurological defects, however, remains unclear. Invertebrates provide an attractive model to study the effects of iron on neuronal development since many of the genes involved in iron metabolism are conserved, and the organisms are amenable to genetic and cytological techniques. We have examined synapse growth specifically under conditions of iron deficiency in the Drosophila circadian clock circuit. We show that projections of the small ventrolateral clock neurons to the protocerebrum of the adult Drosophila brain are significantly reduced upon chelation of iron from the diet. This growth defect persists even when iron is restored to the diet. Genetic neuronal knockdown of ferritin 1 or ferritin 2, critical components of iron storage and transport, does not affect synapse growth in these cells. Together, these data indicate that dietary iron is necessary for central brain synapse formation in the fly and further validate the use of this model to study the function of iron homeostasis on brain development

    Study of the microstructure resulting from brazed aluminium materials used in heat exchangers

    Get PDF
    Re-solidification of AA4343 cladding after brazing as well as the related precipitation in the modified AA3003 core material have been investigated. Analysis of the re-solidified material showed that partial dissolution of the core alloy occurs in both the brazing joints and away of them. Far from the brazing joints, the dissolution is, however, limited and diffusion of silicon from the liquid into the core material leads to solid-state precipitation in the so-called “band of dense precipitates” (BDP). On the contrary, the dissolution is enhanced in the brazing joint to such an extent that no BDP could be observed. The intermetallic phases present in the resolidified areas as well as in the core material have been analyzed and found to be mainly cubic alpha-Al(Mn,Fe)Si. These results were then compared to predictions made with available phase diagram information

    Natural Host Genetic Resistance to Lentiviral CNS Disease: A Neuroprotective MHC Class I Allele in SIV-Infected Macaques

    Get PDF
    Human immunodeficiency virus (HIV) infection frequently causes neurologic disease even with anti-retroviral treatment. Although associations between MHC class I alleles and acquired immunodeficiency syndrome (AIDS) have been reported, the role MHC class I alleles play in restricting development of HIV-induced organ-specific diseases, including neurologic disease, has not been characterized. This study examined the relationship between expression of the MHC class I allele Mane-A*10 and development of lentiviral-induced central nervous system (CNS) disease using a well-characterized simian immunodeficiency (SIV)/pigtailed macaque model. The risk of developing CNS disease (SIV encephalitis) was 2.5 times higher for animals that did not express the MHC class I allele Mane-A*10 (P = 0.002; RR = 2.5). Animals expressing the Mane-A*10 allele had significantly lower amounts of activated macrophages, SIV RNA, and neuronal dysfunction in the CNS than Mane-A*10 negative animals (P<0.001). Mane-A*10 positive animals with the highest CNS viral burdens contained SIV gag escape mutants at the Mane-A*10-restricted KP9 epitope in the CNS whereas wild type KP9 sequences dominated in the brain of Mane-A*10 negative animals with comparable CNS viral burdens. These concordant findings demonstrate that particular MHC class I alleles play major neuroprotective roles in lentiviral-induced CNS disease

    DURABILITY OF MASS TIMBER STRUCTURES: A REVIEW OF THE BIOLOGICAL RISKS

    Get PDF
    Mass timber structures have the potential to change wooden construction on a global scale. Numerous mass timber high-rise buildings are in planning, under development or already built and their performance will alter how architects and engineers view wood as a material. To date, the discussion of material durability and biodegradation in these structures has been limited. While all materials can be degraded by wetting, the potential for biodegradation of wood in a mass timber building requires special consideration. Identifying and eliminating the conditions that might lead to this degradation will be critical for ensuring proper performance of wood in these structures. This article reviews and contrasts potential sources of biodegradation that exist for traditional wood construction with those in mass timber construction and identifies methods for limiting the degradation risk. Finally, future research needs are outlined

    Assessing Autism in Deaf/Hard-of-Hearing Youths: Interdisciplinary Teams, COVID Considerations, and Future Directions

    Get PDF
    Autism spectrum disorders are more prevalent in children who are Deaf or Hard of Hearing (D/HH) than in the general population. This potential for diagnostic overlap underscores the importance of understanding the best approaches for assessing autism spectrum disorder in D/HH youths. Despite the recognition of clinical significance, youths who are D/HH are often identified as autistic later than individuals with normal hearing, which results in delayed access to appropriate early intervention services. Three primary barriers to early identification include behavioral phenotypic overlap, a lack of “gold-standard” screening and diagnostic tools for this population, and limited access to qualified clinicians. In the current article, we seek to address these barriers to prompt an appropriate identification of autism by providing recommendations for autism assessment in children who are D/HH from an interdisciplinary hearing and development clinic, including virtual service delivery during COVID-19. Strengths, gaps, and future directions for implementation are addressed

    Coordinated Regulation of SIV Replication and Immune Responses in the CNS

    Get PDF
    Central nervous system (CNS) invasion during acute-stage HIV-infection has been demonstrated in a small number of individuals, but there is no evidence of neurological impairment at this stage and virus infection in brain appears to be controlled until late-stage disease. Using our reproducible SIV macaque model to examine the earliest stages of infection in the CNS, we identified immune responses that differentially regulate inflammation and virus replication in the brain compared to the peripheral blood and lymphoid tissues. SIV replication in brain macrophages and in brain of SIV-infected macaques was detected at 4 days post-inoculation (p.i.). This was accompanied by upregulation of innate immune responses, including IFNβ, IFNβ-induced gene MxA mRNA, and TNFα. Additionally, IL-10, the chemokine CCL2, and activation markers in macrophages, endothelial cells, and astrocytes were all increased in the brain at four days p.i. We observed synchronous control of virus replication, cytokine mRNA levels and inflammatory markers (MHC Class II, CD68 and GFAP) by 14 days p.i.; however, control failure was followed by development of CNS lesions in the brain. SIV infection was accompanied by induction of the dominant-negative isoform of C/EBPβ, which regulates SIV, CCL2, and IL6 transcription, as well as inflammatory responses in macrophages and astrocytes. This synchronous response in the CNS is in part due to the effect of the C/EBPβ on virus replication and cytokine expression in macrophage-lineage cells in contrast to CD4+ lymphocytes in peripheral blood and lymphoid tissues. Thus, we have identified a crucial period in the brain when virus replication and inflammation are controlled. As in HIV-infected individuals, though, this control is not sustained in the brain. Our results suggest that intervention with antiretroviral drugs or anti-inflammatory therapeutics with CNS penetration would sustain early control. These studies further suggest that interventions should target HIV-infected individuals with increased CCL2 levels or HIV RNA in the CNS

    Cunws/rgo Based Transparent Conducting Electrodes As A Replacement Of Ito In Opto-electric Devices

    Get PDF
    Transparent electrodes that conduct electrical current and allow light to pass through are widely used as the essential component in various opto-electric devices such as light emitting diodes, solar cells, photodectectors and touch screens. Currently, Indium Tin oxide (ITO) is the best, commercially available transparent conducting electrode (TCE). However, ITO is too expensive owing high cost on indium. Furthermore ITO thin films are too brittle to be used in flexible devices. To fulfill the demand of TCEs for wide range of applications, high performance ITO alternatives are required. Herein we demonstrate an approach for the successful, solution based synthesis of high aspect ratio copper nanowires, which were later combined with reduced graphene oxide (rGO), in order to produce smooth thin film TCEs on both glass and flexible substrate. Structure and component characterization for these electrodes was carried out through Four Probe, Spectrophotometer, Scanning electron Microscope (SEM), Transmission Electron Microscope (TEM) and Atomic Field Microscopy (AFM). In addition to the morphological and electrical characterization, these samples were also tested for their durability by carrying out experiments that involved exposure to various environmental conditions and electrode bending. Our fabricated transparent electrodes exhibited high performance with a transmittance of 91.6% and a sheet resistance of 9 O/sq. Furthermore, the electrodes showed no notable loss in performance during the durability testing experiments. Such results make them as replacement for indium tin oxide as a transparent electrode and presents a great opportunity to accelerate the mass development of devices like high efficiency hybrid silicon photovoltaics via simple and rapid soluble processes.qscienc

    Copper nanowires and Graphene nano-composite based electrodes with high transparency and conductivity

    Get PDF
    Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.In this paper, we present ITO-free hybrid transparent conducting electrodes that are based on bilayers of reduced Graphene Oxide (rGO) and Copper Nanowires (CuNWs). The unique structural features of these in-house fabricated electrodes allowed for superior performance with an optical transmittance of 84% and sheet resistance of 21.7 Ω/sq obtained, showing their potential of becoming a replacement for ITO based electrodes. The fabricated hybrid electrodes exhibited extreme stability when subjected to various environmental and durability tests. Adoption of such high performance TCEs, will lead to simple, versatile and cost effective solutions for next generation optoelectronics industry.cf201

    Gendered self-views across 62 countries: A test of competing models

    Get PDF
    Social role theory posits that binary gender gaps in agency and communion should be larger in less egalitarian countries, reflecting these countries’ more pronounced sex-based power divisions. Conversely, evolutionary and self-construal theorists suggest that gender gaps in agency and communion should be larger in more egalitarian countries, reflecting the greater autonomy support and flexible self-construction processes present in these countries. Using data from 62 countries (N = 28,640), we examine binary gender gaps in agentic and communal self-views as a function of country-level objective gender equality (the Global Gender Gap Index) and subjective distributions of social power (the Power Distance Index). Findings show that in more egalitarian countries, gender gaps in agency are smaller and gender gaps in communality are larger. These patterns are driven primarily by cross-country differences in men’s self-views and by the Power Distance Index (PDI) more robustly than the Global Gender Gap Index (GGGI). We consider possible causes and implications of these findings.info:eu-repo/semantics/acceptedVersio

    Evaluation of PD 404,182 as an Anti-HIV and Anti-Herpes Simplex Virus Microbicide

    Get PDF
    PD 404,182 (PD) is a synthetic compound that was found to compromise HIV integrity via interaction with a nonenvelope protein viral structural component (A. M. Chamoun et al., Antimicrob. Agents Chemother. 56:672–681, 2012). The present study evaluates the potential of PD as an anti-HIV microbicide and establishes PD's virucidal activity toward another pathogen, herpes simplex virus (HSV). We show that the anti-HIV-1 50% inhibitory concentration (IC(50)) of PD, when diluted in seminal plasma, is ∼1 μM, similar to the IC(50) determined in cell culture growth medium, and that PD retains full anti-HIV-1 activity after incubation in cervical fluid at 37°C for at least 24 h. In addition, PD is nontoxic toward vaginal commensal Lactobacillus species (50% cytotoxic concentration [CC(50)], >300 μM), freshly activated human peripheral blood mononuclear cells (CC(50), ∼200 μM), and primary CD4(+) T cells, macrophages, and dendritic cells (CC(50), >300 μM). PD also exhibited high stability in pH-adjusted Dulbecco's phosphate-buffered saline with little to no activity loss after 8 weeks at pH 4 and 42°C, indicating suitability for formulation for transportation and storage in developing countries. Finally, for the first time, we show that PD inactivates herpes simplex virus 1 (HSV-1) and HSV-2 at submicromolar concentrations. Due to the prevalence of HSV infection, the ability of PD to inactivate HSV may provide an additional incentive for use as a microbicide. The ability of PD to inactivate both HIV-1 and HSV, combined with its low toxicity and high stability, warrants additional studies for the evaluation of PD's microbicidal candidacy in animals and humans
    corecore