228 research outputs found
Stripping experiments in carbon foils with heavy ions in the energy range of 0.4-0.9 mev/a
We studied the properties of heavy ions stripped by carbon foils. Ni, I and Au ions of 0.4 - 0.9 MeV/A were used to bombard foils of 5 - 200 μg/cm 2. In these measurements the ions were detected in a Browne-Buechner spectrometer. We measured the angular straggling of the ions and the energy straggling. We looked for the behaviour of the foils under impact of large beam densities (several μAp/cm2 on an area of 1-2 mm2). We observed the thickness variations of the foils during bombardment in a vacuum of ∼ 10-6 and 10-7 torr. We looked for the evolution of the energy straggling during exposure and conclude that this parameter does not change in an important way. This means that neither thickening nor sputtering affects the homogeneity of the foil. Results on the lifetime of the bombarded foils are reported
The Burden of Trachoma in South Sudan: Assessing the Health Losses from a Condition of Graded Severity
Trachoma is an infectious disease that is endemic to the Republic of South Sudan. In the absence of appropriate treatment recurrent re-infection in an individual will lead to progressively severe states of trachoma, eventually leading to the loss of visual acuity and finally blindness. Here we distinguish between three separate states of disease: trachoma with normal vision, trachoma with low vision and trachoma with blindness. The first of these states, trachoma with normal vision, is the least severe and the impact of this state on a population has not been well investigated. Trachoma, even before any loss of vision, comes with a great deal of pain and social consequences, and thus disability. In this study we employ data from South Sudan and estimate the burden caused by trachoma with normal vision for the first time. In doing so, we also reveal the extent of the gaps in our knowledge surrounding the natural history of trachoma and highlight areas of research that require urgent attention
Lattice QCD Calculation of Hadron Scattering Lengths
Method of calculating hadron multi-point functions and disconnected quark
loop contributions which are not readily accessible through conventional
techniques is proposed. Results are reported for pion-pion, pion-nucleon and
nucleon-nucleon scattering lengths and the flavor singlet-non singlet meson
mass splitting estimated in quenched QCD.Comment: 6 pages. Contribution to Lattice '93. Latex file, style file
espcrc2.sty needed.(appended at the end) Figures are also included as epsf
file
Genome-wide compendium and functional assessment of in vivo heart enhancers
Whole-genome sequencing is identifying growing numbers of non-coding variants in human disease studies, but the lack of accurate functional annotations prevents their interpretation. We describe the genome-wide landscape of distant-acting enhancers active in the developing and adult human heart, an organ whose impairment is a predominant cause of mortality and morbidity. Using integrative analysis of >35 epigenomic data sets from mouse and human pre- and postnatal hearts we created a comprehensive reference of >80,000 putative human heart enhancers. To illustrate the importance of enhancers in the regulation of genes involved in heart disease, we deleted the mouse orthologs of two human enhancers near cardiac myosin genes. In both cases, we observe in vivo expression changes and cardiac phenotypes consistent with human heart disease. Our study provides a comprehensive catalogue of human heart enhancers for use in clinical whole-genome sequencing studies and highlights the importance of enhancers for cardiac function
Sensitivity to electricity – Temporal changes in Austria
<p>Abstract</p> <p>Background</p> <p>An increasing number of persons suffer from non-specific health symptoms such as headache, sleep disturbances, difficulties in concentrating and more. In lack of a medical explanation, more and more persons take refuge to the assumption that they were electromagnetic hypersensitive (EHS) and electromagnetic pollution causes their problems. The discussion whether electromagnetic fields (EMF) could cause such adverse health effects is still ongoing.</p> <p>Methods</p> <p>Based on the Austrian inhabitants a statistical cross-sample of the general population with regard to age, gender and federal state had been investigated to assess the actual situation and potential temporal changes in comparison with a former study of 1994. In a telephone survey a total number of 526 persons were included.</p> <p>Results</p> <p>This study showed an actual EHS prevalence of 3.5% compared with 2% estimated in 1994. About 70% of the sample believed that electromagnetic pollution could be a risk factor for health. More than 30% declared to at least some degree to be concerned about their well-being near mobile phone base stations or power lines. However, only 10% were actively looking for specific information. Media triggered EHS hypothesis in 24% of the cases.</p> <p>Conclusion</p> <p>The results show that concerns about EMF did not decrease with time in spite of scientific studies and health risk assessments concluding that a causal relationship of EMF below recommended reference levels and non-specific health symptoms would be implausible.</p
CXC receptor-4 mRNA silencing abrogates CXCL12-induced migration of colorectal cancer cells
<p>Abstract</p> <p>Background</p> <p>Interactions between CXCR4 and its ligand CXCL12 have been shown to be involved in cancer progression in colorectal cancer (CRC). We performed a comparative CXCL12/CXCR4 expression analysis and assessed the effect of external CXCL12 stimulation on migration of CRC cells without and with CXCR4 inhibition.</p> <p>Methods</p> <p>Expression of CXCL12/CXCR4 was assessed by quantitative real-time PCR, ELISA and immunohistochemistry in resection specimens of 50 CRC patients as well as in the corresponding normal tissues and in three human CRC cell lines with different metastatic potential (Caco-2, SW480 and HT-29). Migration assays were performed after stimulation with CXCL12 and CXCR4 was inhibited by siRNA and neutralizing antibodies.</p> <p>Results</p> <p>In CRC tissues CXCL12 was significantly down-regulated and CXCR4 was significantly up-regulated compared to the corresponding normal tissues. In cell lines CXCR4 was predominantly expressed in SW480 and less pronounced in HT-29 cells. CXCL12 was only detectable in Caco-2 cells. CXCL12 stimulation had no impact on Caco-2 cells but significantly increased migration of CXCR4 bearing SW480 and HT-29 cells. This effect was significantly abrogated by neutralizing anti-CXCR4 antibody as well as by CXCR4 siRNAs (P < 0.05).</p> <p>Conclusions</p> <p>CXCR4 expression was up-regulated in CRC and CXCL12 stimulation increased migration in CXCR4 bearing cell lines. Migration was inhibited by both neutralizing CXCR4 antibodies and CXCR4 siRNAs. Thus, the expression and functionality of CXCR4 might be associated with the metastatic potential of CRC cells and CXCL12/CXCR4 interactions might therefore constitute a promising target for specific treatment interventions.</p
Re-thinking residential mobility: Linking lives through time and space.
This is the final version of the article. It first appeared from SAGE via http://dx.doi.org/10.1177/0309132515575417While researchers are increasingly re-conceptualizing international migration, far less attention has been devoted to re-thinking short-distance residential mobility and immobility. In this paper we harness the life course approach to propose a new conceptual framework for residential mobility research. We contend that residential mobility and immobility should be re-conceptualized as relational practices that link lives through time and space while connecting people to structural conditions. Re-thinking and re-assessing residential mobility by exploiting new developments in longitudinal analysis will allow geographers to understand, critique and address pressing societal challenges.Rory Coulter’s work on this paper was partly supported by an Economic and Social Research Council grant [ES/L009498/1]. Maarten van Ham’s contribution was supported by funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013) / ERC Grant Agreement n. 615159 (ERC Consolidator Grant DEPRIVEDHOODS, Socio-spatial inequality, deprived neighbourhoods, and neighbourhood effects); and from the Marie Curie programme under the European Union’s Seventh Framework Programme (FP/2007–2013) / Career Integration Grant no. PCIG10-GA-2011-303728 (CIG Grant NBHCHOICE, Neighbourhood choice, neighbourhood sorting, and neighbourhood effects). Allan Findlay’s work was supported by an Economic and Social Research Council grant [ES/K007394/1]
Dissection of the Role of PfEMP1 and ICAM-1 in the Sensing of Plasmodium falciparum-Infected Erythrocytes by Natural Killer Cells
BACKGROUND: Host innate immunity contributes to malaria clinical outcome by providing protective inflammatory cytokines such as interferon-γ, and by shaping the adaptive immune response. Plasmodium falciparum (Pf) is the etiologic agent of the most severe forms of human malaria. Natural Killer (NK) cells are lymphocytes of the innate immune system that are the first effectors to produce interferon-γ in response to Pf. However, the molecular bases of Pf-NK cell recognition events are unknown. Our study focuses on the role of Pf erythrocyte membrane protein 1 (PfEMP1), a major Pf virulence factor. PfEMP1 is expressed on parasitized-erythrocytes and participates to vascular obstruction through the binding to several host receptors. PfEMP1 is also a pivotal target for host antibody response to Pf infection. METHODOLOGY/PRINCIPAL FINDINGS: Using genetically-engineered parasite mutant strains, a human genetic deficiency, and blocking antibodies, we identified two receptor-ligand pairs involved in two uncoupled events occurring during the sensing of Pf infection by NK cells. First, PfEMP1 interaction with one of its host receptor, chondroitin sulfate A, mediates the cytoadhesion of Pf-infected erythrocytes to human NK cell lines, but is not required for primary NK cell activation. Second, intercellular adhesion molecule-1 (ICAM-1), another host receptor for PfEMP1, is mandatory for NK cell interferon-γ response. In this case, ICAM-1 acts via its engagement with its host ligand, LFA-1, and not with PfEMP1, consistent with the obligatory cross-talk of NK cells with macrophages for their production of interferon-γ. CONCLUSION/SIGNIFICANCE: PfEMP1-independent but ICAM-1/LFA-1-dependent events occurring during NK cell activation by Pf highlight the fundamental role of cellular cooperation during innate immune response to malaria
Genome-wide fetalization of enhancer architecture in heart disease
Heart disease is associated with re-expression of key transcription factors normally active only during prenatal development of the heart. However, the impact of this reactivation on the regulatory landscape in heart disease is unclear. Here, we use RNA-seq and ChIP-seq targeting a histone modification associated with active transcriptional enhancers to generate genome-wide enhancer maps from left ventricle tissue from up to 26 healthy controls, 18 individuals with idiopathic dilated cardiomyopathy (DCM), and five fetal hearts. Healthy individuals have a highly reproducible epigenomic landscape, consisting of more than 33,000 predicted heart enhancers. In contrast, we observe reproducible disease-associated changes in activity at 6,850 predicted heart enhancers. Combined analysis of adult and fetal samples reveals that the heart disease epigenome and transcriptome both acquire fetal-like characteristics, with 3,400 individual enhancers sharing fetal regulatory properties. We also provide a comprehensive data resource (http://heart.lbl.gov) for the mechanistic exploration of DCM etiology
Comparative Structural Analysis of Human DEAD-Box RNA Helicases
DEAD-box RNA helicases play various, often critical, roles in all processes where RNAs are involved. Members of this family of proteins are linked to human disease, including cancer and viral infections. DEAD-box proteins contain two conserved domains that both contribute to RNA and ATP binding. Despite recent advances the molecular details of how these enzymes convert chemical energy into RNA remodeling is unknown. We present crystal structures of the isolated DEAD-domains of human DDX2A/eIF4A1, DDX2B/eIF4A2, DDX5, DDX10/DBP4, DDX18/myc-regulated DEAD-box protein, DDX20, DDX47, DDX52/ROK1, and DDX53/CAGE, and of the helicase domains of DDX25 and DDX41. Together with prior knowledge this enables a family-wide comparative structural analysis. We propose a general mechanism for opening of the RNA binding site. This analysis also provides insights into the diversity of DExD/H- proteins, with implications for understanding the functions of individual family members
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