259 research outputs found

    Electroactive nanoporous metal oxides and chalcogenides by chemical design

    Get PDF
    The archetypal silica- and aluminosilicate-based zeolite-type materials are renowned for wide-ranging applications in heterogeneous catalysis, gas-separation and ion-exchange. Their compositional space can be expanded to include nanoporous metal chalcogenides, exemplified by germanium and tin sulfides and selenides. By comparison with the properties of bulk metal dichalcogenides and their 2D derivatives, these open-framework analogues may be viewed as three-dimensional semiconductors filled with nanometer voids. Applications exist in a range of molecule size and shape discriminating devices. However, what is the electronic structure of nanoporous metal chalcogenides? Herein, materials modeling is used to describe the properties of a homologous series of nanoporous metal chalcogenides denoted np-MX2, where M = Si, Ge, Sn, Pb, and X = O, S, Se, Te, with Sodalite, LTA and aluminum chromium phosphate-1 structure types. Depending on the choice of metal and anion their properties can be tuned from insulators to semiconductors to metals with additional modification achieved through doping, solid solutions, and inclusion (with fullerene, quantum dots, and hole transport materials). These systems form the basis of a new branch of semiconductor nanochemistry in three dimensions

    cGMP Recombinant FIX for IV and Oral Hemophilia B Therapy

    Get PDF
    Three specific aims are proposed: Specific Aim # 1. Process engineer and scale-up the recovery and purification of transgenic recombinant human Factor IX. The University of Nebraska-Lincoln Biological Process Development Facility will complete process development and scale-up, and produce clinical grade materials for preclinical studies. The endpoint is a proposed final product specification to help facilitate transfer to current Good Manufacturing Practices compliant production of clinical grade material to support an Investigational New Drug filing with the United States Food and Drug Administration (FDA) leading to clinical trials. Specific Aim #2. Characterize and formulate transgenic recombinant human Factor IX for intravenous dosage, and evaluate in a hemophilia B dog model. These activities are directed toward characterization of the product important to assure the provision of safe and reproducibly effective hemostasis. The results of these investigations will help support an IND filing with the FDA. Specific Aim # 3. Develop an oral dosage form of transgenic recombinant human Factor IX, and evaluate in hemophilia B mice and dog models. Oral administration of coagulation therapy will obviate the invasiveness, discomfort, potential for opportunistic infection, and complications of storage and supplies that accompany intravenous administration. Oral dosage forms of Factor IX will thus greatly increase the proportion of the patient population that can be treated. There is also published evidence suggesting that oral administration may reduce the potential for complicating immune responses to replacement therapy, especially in patients with severe hemophilia

    Complex systems and applied linguistics

    Get PDF
    This book introduces and develops the potential of complex systems as a metaphor or supra-theory for systems in applied linguistics. Change and heterogeneity are central to complex systems theory and to the resonances that we find between complex systems and applied linguistics systems. The book explores these resonances and what happens when complex systems theory is used to make sense of central areas of applied linguistic concerns: language, language learning, discourse and the language classroom. Principles of complex systems theory are explained, drawing on work that has been most developed in the biological sciences and that is being extended into the social sciences, developmental psychology and other applied disciplines. These principles importantly include descriptions of change over time (system dynamics) that work for all levels and scales: movement from temporary and relative stability through adaptive behaviours and self-organisation to the emergence of new patterns that are not amenable to reductive explanations. Seeing applied systems as complex, adaptive and dynamic opens up new conceptualisations of properties and activities, enables new questions about how people use, learn and teach languages, and demands new ways of investigating behaviour and development

    Demand-side financing for maternal and newborn health: what do we know about factors that affect implementation of cash transfers and voucher programmes?

    Get PDF
    BackgroundDemand-side financing (DSF) interventions, including cash transfers and vouchers, have been introduced to promote maternal and newborn health in a range of low- and middle-income countries. These interventions vary in design but have typically been used to increase health service utilisation by offsetting some financial costs for users, or increasing household income and incentivising 'healthy behaviours'. This article documents experiences and implementation factors associated with use of DSF in maternal and newborn health.MethodsA secondary analysis (using an adapted Supporting the Use of Research Evidence framework - SURE) was performed on studies that had previously been identified in a systematic review of evidence on DSF interventions in maternal and newborn health.ResultsThe article draws on findings from 49 quantitative and 49 qualitative studies. The studies give insights on difficulties with exclusion of migrants, young and multiparous women, with demands for informal fees at facilities, and with challenges maintaining quality of care under increasing demand. Schemes experienced difficulties if communities faced long distances to reach participating facilities and poor access to transport, and where there was inadequate health infrastructure and human resources, shortages of medicines and problems with corruption. Studies that documented improved care-seeking indicated the importance of adequate programme scope (in terms of programme eligibility, size and timing of payments and voucher entitlements) to address the issue of concern, concurrent investments in supply-side capacity to sustain and/or improve quality of care, and awareness generation using community-based workers, leaders and women's groups. ConclusionsEvaluations spanning more than 15 years of implementation of DSF programmes reveal a complex picture of experiences that reflect the importance of financial and other social, geographical and health systems factors as barriers to accessing care. Careful design of DSF programmes as part of broader maternal and newborn health initiatives would need to take into account these barriers, the behaviours of staff and the quality of care in health facilities. Research is still needed on the policy context for DSF schemes in order to understand how they become sustainable and where they fit, or do not fit, with plans to achieve equitable universal health coverage

    Kaposi's Sarcoma Associated Herpes Virus (KSHV) Induced COX-2: A Key Factor in Latency, Inflammation, Angiogenesis, Cell Survival and Invasion

    Get PDF
    Kaposi's sarcoma (KS), an enigmatic endothelial cell vascular neoplasm, is characterized by the proliferation of spindle shaped endothelial cells, inflammatory cytokines (ICs), growth factors (GFs) and angiogenic factors. KSHV is etiologically linked to KS and expresses its latent genes in KS lesion endothelial cells. Primary infection of human micro vascular endothelial cells (HMVEC-d) results in the establishment of latent infection and reprogramming of host genes, and cyclooxygenase-2 (COX-2) is one of the highly up-regulated genes. Our previous study suggested a role for COX-2 in the establishment and maintenance of KSHV latency. Here, we examined the role of COX-2 in the induction of ICs, GFs, angiogenesis and invasive events occurring during KSHV de novo infection of endothelial cells. A significant amount of COX-2 was detected in KS tissue sections. Telomerase-immortalized human umbilical vein endothelial cells supporting KSHV stable latency (TIVE-LTC) expressed elevated levels of functional COX-2 and microsomal PGE2 synthase (m-PGES), and secreted the predominant eicosanoid inflammatory metabolite PGE2. Infected HMVEC-d and TIVE-LTC cells secreted a variety of ICs, GFs, angiogenic factors and matrix metalloproteinases (MMPs), which were significantly abrogated by COX-2 inhibition either by chemical inhibitors or by siRNA. The ability of these factors to induce tube formation of uninfected endothelial cells was also inhibited. PGE2, secreted early during KSHV infection, profoundly increased the adhesion of uninfected endothelial cells to fibronectin by activating the small G protein Rac1. COX-2 inhibition considerably reduced KSHV latent ORF73 gene expression and survival of TIVE-LTC cells. Collectively, these studies underscore the pivotal role of KSHV induced COX-2/PGE2 in creating KS lesion like microenvironment during de novo infection. Since COX-2 plays multiple roles in KSHV latent gene expression, which themselves are powerful mediators of cytokine induction, anti-apoptosis, cell survival and viral genome maintainence, effective inhibition of COX-2 via well-characterized clinically approved COX-2 inhibitors could potentially be used in treatment to control latent KSHV infection and ameliorate KS

    Mutant-IDH1-dependent chromatin state reprogramming, reversibility, and persistence

    Get PDF
    Mutations in IDH1 and IDH2 (encoding isocitrate dehydrogenase 1 and 2) drive the development of gliomas and other human malignancies. Mutant IDH1 induces epigenetic changes that promote tumorigenesis, but the scale and reversibility of these changes are unknown. Here, using human astrocyte and glioma tumorsphere systems, we generate a large-scale atlas of mutant-IDH1-induced epigenomic reprogramming. We characterize the reversibility of the alterations in DNA methylation, the histone landscape, and transcriptional reprogramming that occur following IDH1 mutation. We discover genome-wide coordinate changes in the localization and intensity of multiple histone marks and chromatin states. Mutant IDH1 establishes a CD24+ population with a proliferative advantage and stem-like transcriptional features. Strikingly, prolonged exposure to mutant IDH1 results in irreversible genomic and epigenetic alterations. Together, these observations provide unprecedented high-resolution molecular portraits of mutant-IDH1-dependent epigenomic reprogramming. These findings have substantial implications for understanding of mutant IDH function and for optimizing therapeutic approaches to targeting IDH-mutant tumors
    • …
    corecore