5,031 research outputs found

    Dispersion enhancement and damping by buoyancy driven flows in 2D networks of capillaries

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    The influence of a small relative density difference on the displacement of two miscible liquids is studied experimentally in transparent 2D networks of micro channels. Both stable displacements in which the denser fluid enters at the bottom of the cell and displaces the lighter one and unstable displacements in which the lighter fluid is injected at the bottom and displaces the denser one are realized. Except at the lowest mean flow velocity U, the average C(x,t)C(x,t) of the relative concentration satisfies a convection-dispersion equation. The dispersion coefficient is studied as function of the relative magnitude of fluid velocity and of the velocity of buoyancy driven fluid motion. A model is suggested and its applicability to previous results obtained in 3D media is discussed

    Conserved transcription factor binding sites of cancer markers derived from primary lung adenocarcinoma microarrays

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    Gene transcription in a set of 49 human primary lung adenocarcinomas and 9 normal lung tissue samples was examined using Affymetrix GeneChip technology. A total of 3442 genes, called the set M AD, were found to be either up- or down-regulated by at least 2-fold between the two phenotypes. Genes assigned to a particular gene ontology term were found, in many cases, to be significantly unevenly distributed between the genes in and outside M AD. Terms that were overrepresented in M AD included functions directly implicated in the cancer cell metabolism. Based on their functional roles and expression profiles, genes in M AD were grouped into likely co-regulated gene sets. Highly conserved sequences in the 5 kb region upstream of the genes in these sets were identified with the motif discovery tool, MoDEL. Potential oncogenic transcription factors and their corresponding binding sites were identified in these conserved regions using the TRANSFAC 8.3 database. Several of the transcription factors identified in this study have been shown elsewhere to be involved in oncogenic processes. This study searched beyond phenotypic gene expression profiles in cancer cells, in order to identify the more important regulatory transcription factors that caused these aberrations in gene expressio

    Social Forestry - Why and for Whom? a Comparison of Policies in Vietnam and Indonesia

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    Community forestry or social forestry (henceforth referred collectively as SF) programs have become new modes of forest management empowering local managers and hence, allowing integration of diverse local practices and support of local livelihoods. Implementation of these initiatives, however, face multiple challenges. State-prescribed community programs, for example, will remain isolated efforts if changes in the overall economic and social governance frameworks, including the devolution of rights to local users is lacking. Financial sustainability of these measures remains often uncertain and equity issues inherent to groups and communities formed for SF, can be exacerbated. In this article, we pose the question: Whose interests do SF policies serve? The effectiveness of SF would depend on the motivations and aims for a decentralization of forest governance to the community. In order to understand the underlying motivations behind the governments' push for SF, we examine national policies in Vietnam and Indonesia, changes in their policies over time and the shift in discourses influencing how SF has evolved. Vietnam and Indonesia are at different sides of the spectrum in democratic ambitions and forest abundance, and present an intriguing comparison in the recent regional push towards SF in Southeast Asia. We discuss the different interpretations of SF in these two countries and how SF programs are implemented. Our results show that governments, influenced by global discourse, are attempting to regulate SF through formal definitions and regulations. Communities on the other hand, might resist by adopting, adapting or rejecting formal schemes. In this tension, SF, in general adopted to serve the interest of local people, in practice SF has not fulfilled its promise

    Conserved transcription factor binding sites of cancer markers derived from primary lung adenocarcinoma microarrays

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    Gene transcription in a set of 49 human primary lung adenocarcinomas and 9 normal lung tissue samples was examined using Affymetrix GeneChip technology. A total of 3442 genes, called the set M(AD), were found to be either up- or down-regulated by at least 2-fold between the two phenotypes. Genes assigned to a particular gene ontology term were found, in many cases, to be significantly unevenly distributed between the genes in and outside M(AD). Terms that were overrepresented in M(AD) included functions directly implicated in the cancer cell metabolism. Based on their functional roles and expression profiles, genes in M(AD) were grouped into likely co-regulated gene sets. Highly conserved sequences in the 5 kb region upstream of the genes in these sets were identified with the motif discovery tool, MoDEL. Potential oncogenic transcription factors and their corresponding binding sites were identified in these conserved regions using the TRANSFAC 8.3 database. Several of the transcription factors identified in this study have been shown elsewhere to be involved in oncogenic processes. This study searched beyond phenotypic gene expression profiles in cancer cells, in order to identify the more important regulatory transcription factors that caused these aberrations in gene expression

    Stage-Specific Generation of Human Pluripotent Stem Cell Derived Lung Models to Measure CFTR Function

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    Human embryonic stem cells (ES) and induced pluripotent stem cells (iPSC) are powerful tools that have the potential to generate in vitro human lung epithelial cells. However, challenges in efficiency and reproducibility remain in utilizing the cells for therapy discovery platforms. Here, we optimize our previously published protocols to efficiently generate three developmental stages of the lung model (fetal lung epithelial progenitors, fLEP; immature airway epithelial spheroid, AES; air-liquid interface culture, ALI), and demonstrate its potential for cystic fibrosis (CF) drug discovery platforms. The stepwise approach directs differentiation from hPSC to definitive endoderm, anterior ventral foregut endoderm, and fetal lung progenitor cells. The article also describes the generation of immature airway epithelial spheroids in Matrigel with epithelial cells sorted by a magnetic-activated cell sorting system, and the generation of adult-like airway epithelia through air-liquid interface conditions. We demonstrate that this optimized procedure generates remarkably higher cystic fibrosis transmembrane conductance regulator (CFTR) expression and function than our previous method, and thus is uniquely suitable for CF research applications. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: hESC/hiPSC differentiation to fetal lung progenitors Basic Protocol 2: Formation of airway epithelial spheroids Alternate Protocol 1: Cryopreservation of airway epithelial spheroids Basic Protocol 3: Differentiation and maturation in air-liquid interface culture Alternate Protocol 2: Differentiation and maturation of epithelial progenitors from airway epithelial spheroids in ALI culture

    Saving lives beyond 2020: The next steps

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    Road safety analysis can be used to understand what has been successful in the past and what needs to be changed in order to be successful to reduce severe road trauma going forward and ultimately what\u27s needed to achieve zero. This chapter covers some of the tools used to retrospectively evaluate real-life benefits of road safety measures and methods used to predict the combined effects of interventions in a road safety action plan as well as to estimate if they are sufficient to achieve targets near-term and long-term. Included are also a brief overview of methods to develop boundary conditions on what constitutes a Safe System for different road users. Further to that, the chapter lists some arguments for the need of high-quality mass and in-depth data to ensure confidence in the results and conclusions from road safety analysis. Finally, a few key messages are summarized

    pEPito: a significantly improved non-viral episomal expression vector for mammalian cells

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    <p>Abstract</p> <p>Background</p> <p>The episomal replication of the prototype vector pEPI-1 depends on a transcription unit starting from the constitutively expressed <it>Cytomegalovirus </it>immediate early promoter (CMV-IEP) and directed into a 2000 bp long <it>matrix attachment region sequence </it>(MARS) derived from the human ÎČ-interferon gene. The original pEPI-1 vector contains two mammalian transcription units and a total of 305 CpG islands, which are located predominantly within the vector elements necessary for bacterial propagation and known to be counterproductive for persistent long-term transgene expression.</p> <p>Results</p> <p>Here, we report the development of a novel vector pEPito, which is derived from the pEPI-1 plasmid replicon but has considerably improved efficacy both <it>in vitro </it>and <it>in vivo</it>. The pEPito vector is significantly reduced in size, contains only one transcription unit and 60% less CpG motives in comparison to pEPI-1. It exhibits major advantages compared to the original pEPI-1 plasmid, including higher transgene expression levels and increased colony-forming efficiencies <it>in vitro</it>, as well as more persistent transgene expression profiles <it>in vivo</it>. The performance of pEPito-based vectors was further improved by replacing the CMV-IEP with the <it>human CMV enhancer/human elongation factor 1 alpha promoter </it>(hCMV/EF1P) element that is known to be less affected by epigenetic silencing events.</p> <p>Conclusions</p> <p>The novel vector pEPito can be considered suitable as an improved vector for biotechnological applications <it>in vitro </it>and for non-viral gene delivery <it>in vivo</it>.</p

    Flocked nasal swab versus nasopharyngeal aspirate for detection of respiratory tract viruses in immunocompromised adults: a matched comparative study

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    <p>Abstract</p> <p>Background</p> <p>Several studies have compared nasal swabs to the more invasive nasopharyngeal aspirate (NPA) for detection of respiratory viruses. Mostly, the comparisons have been performed on immunocompetent children with upper respiratory tract symptoms. The results range from a relatively poor sensitivity for the swabs to an even higher sensitivity than for the NPA. We aimed to investigate the sensitivity of a flocked nasal swab (fNS) on immunocompromised adults with febrile neutropenia.</p> <p>Methods</p> <p>During 16 months, adults with a hematological disorder presenting with febrile neutropenia were enrolled in the study. Paired samples of the fNS and NPA were collected in the outer part of the nasal cavity and the nasopharynx, respectively. The samples were analyzed regarding a panel of 15 respiratory viruses by means of quantitative polymerase chain reaction. Furthermore, as an indirect measure of cell yield by either method, the copy number of the human beta actin gene was also determined. Cohen's kappa was calculated as a measure of agreement of the results obtained from either method. Wilcoxon signed-rank test was used for comparison of cell yield.</p> <p>Results</p> <p>A total of 98 paired samples from a total of 89 patients were collected. Twenty of the pairs had virus detected in at least one of the specimens; 11 in both, 7 in NPA only, and 2 in fNS only. For the fNS, the overall sensitivity for any virus and for rhinovirus only was 65% and 78%, respectively. NPA was significantly superior to the fNS in collecting epithelial cells.</p> <p>Conclusion</p> <p>We found the overall sensitivity of 65% to be too low to replace NPA with this sampling technique in this patient category.</p

    Spin Flipping and Polarization Lifetimes of a 270 MeV Deuteron Beam

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    We recently studied the spin flipping of a 270 MeV vertically polarized deuteron beam stored in the IUCF Cooler Ring. We swept an rf solenoid’s frequency through an rf‐induced spin resonance and observed the effect on the beam’s vector and tensor polarizations. After optimizing the resonance crossing rate and setting the solenoid’s voltage to its maximum value, we obtained a spin‐flip efficiency of about 94 ± 1% for the vector polarization; we also observed a partial spin‐flip of the tensor polarization. We then used the rf‐induced resonance to measure the vector and tensor polarizations’ lifetimes at different distances from the resonance; the polarization lifetime ratio τvector/τtensor was about 1.9 ± 0.4. © 2003 American Institute of PhysicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87679/2/766_1.pd
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