621 research outputs found

    A Search for New Physics with the BEACON Mission

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    The primary objective of the Beyond Einstein Advanced Coherent Optical Network (BEACON) mission is a search for new physics beyond general relativity by measuring the curvature of relativistic space-time around Earth. This curvature is characterized by the Eddington parameter \gamma -- the most fundamental relativistic gravity parameter and a direct measure for the presence of new physical interactions. BEACON will achieve an accuracy of 1 x 10^{-9} in measuring the parameter \gamma, thereby going a factor of 30,000 beyond the present best result involving the Cassini spacecraft. Secondary mission objectives include: (i) a direct measurement of the "frame-dragging" and geodetic precessions in the Earth's rotational gravitomagnetic field, to 0.05% and 0.03% accuracy correspondingly, (ii) first measurement of gravity's non-linear effects on light and corresponding 2nd order spatial metric's effects to 0.01% accuracy. BEACON will lead to robust advances in tests of fundamental physics -- this mission could discover a violation or extension of general relativity and/or reveal the presence of an additional long range interaction in physics. BEACON will provide crucial information to separate modern scalar-tensor theories of gravity from general relativity, probe possible ways for gravity quantization, and test modern theories of cosmological evolution.Comment: 8 pages, 2 figures, 2 table

    Sex-dependent influence of endogenous estrogen in pulmonary hypertension

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    Rationale: The incidence of pulmonary arterial hypertension (PAH) is greater in women suggesting estrogens may play a role in the disease pathogenesis. Experimentally, in males exogenously administered estrogen can protect against PH; however in models that display female susceptibility estrogens may play a causative role. Objectives: To clarify the influence of endogenous estrogen and gender in PH and assess the therapeutic potential of a clinically available aromatase inhibitor. Methods: We interrogated the effect of reduced endogenous estrogen in males and females using the aromatase inhibitor, anastrozole, in two models of PH; the hypoxic mouse and Sugen 5416/hypoxic rat. We also determined the effects of gender on pulmonary expression of aromatase in these models and in lungs from PAH patients. Results: Anastrozole attenuated PH in both models studied, but only in females. To verify this effect was due to reduced estrogenic activity we confirmed that in hypoxic mice inhibition of estrogen receptor alpha also has a therapeutic effect specifically in females. Female rodent lung displays increased aromatase and decreased BMPR2 and Id1 expression compared to male. Anastrozole treatment reversed the impaired BMPR2 pathway in females. Increased aromatase expression was also detected in female human pulmonary artery smooth muscle cells compared to male. Conclusions: The unique phenotype of female pulmonary arteries facilitates the therapeutic effects of anastrozole in experimental PH confirming a role for endogenous estrogen in the disease pathogenesis in females and suggests aromatase inhibitors may have therapeutic potential

    Clinical Determinants and Prognostic Implications of Renin and Aldosterone in Patients with Symptomatic Heart Failure

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    Aims Activation of the renin-angiotensin-aldosterone system plays an important role in the pathophysiology of heart failure (HF) and has been associated with poor prognosis. There are limited data on the associations of renin and aldosterone levels with clinical profiles, treatment response, and study outcomes in patients with HF. Methods and results We analysed 2,039 patients with available baseline renin and aldosterone levels in BIOSTAT-CHF (a systems BIOlogy study to Tailored Treatment in Chronic Heart Failure). The primary outcome was the composite of all-cause mortality or HF hospitalization. We also investigated changes in renin and aldosterone levels after administration of mineralocorticoid receptor antagonists (MRAs) in a subset of the EPHESUS trial and in an acute HF cohort (PORTO). In BIOSTAT-CHF study, median renin and aldosterone levels were 85.3 (percentile(25-75) = 28-247) mu IU/mL and 9.4 (percentile(25-75) = 4.4-19.8) ng/dL, respectively. Prior HF admission, lower blood pressure, sodium, poorer renal function, and MRA treatment were associated with higher renin and aldosterone. Higher renin was associated with an increased rate of the primary outcome [highest vs. lowest renin tertile: adjusted-HR (95% CI) = 1.47 (1.16-1.86), P = 0.002], whereas higher aldosterone was not [highest vs. lowest aldosterone tertile: adjusted-HR (95% CI) = 1.16 (0.93-1.44), P = 0.19]. Renin and/or aldosterone did not improve the BIOSTAT-CHF prognostic models. The rise in aldosterone with the use of MRAs was observed in EPHESUS and PORTO studies. Conclusions Circulating levels of renin and aldosterone were associated with both the disease severity and use of MRAs. By reflecting both the disease and its treatments, the prognostic discrimination of these biomarkers was poor. Our data suggest that the "point" measurement of renin and aldosterone in HF is of limited clinical utility

    Molecular and all solid DFT studies of the magnetic and chemical bonding properties within KM[Cr(CN)6_6] (M = V, Ni) complexes

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    A study at both the molecular and extended solid level in the framework DFT is carried out for KM[Cr(CN)6_6] (M = V, Ni). From molecular calculations, the exchange parameters J are obtained, pointing to the expected magnetic ground states, i.e., antiferromagnetic for M = V with J = -296.5 cm1^{-1} and ferromagnetic for M = Ni with J = +40.5 cm1^{-1}. From solid state computations the same ground states and J magnitudes are confirmed from energy differences. Furthermore an analysis of the site projected density of states and of the chemical bonding is developed in which the cyanide ion linkage is analyzed addressing some isomerism aspects.Comment: new results, 5 tables, 7 fig

    The Vaginal Microbiome: Disease, Genetics and the Environment

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    The vagina is an interactive interface between the host and the environment. Its surface is covered by a protective epithelium colonized by bacteria and other microorganisms. The ectocervix is nonsterile, whereas the endocervix and the upper genital tract are assumed to be sterile in healthy women. Therefore, the cervix serves a pivotal role as a gatekeeper to protect the upper genital tract from microbial invasion and subsequent reproductive pathology. Microorganisms that cross this barrier can cause preterm labor, pelvic inflammatory disease, and other gynecologic and reproductive disorders. Homeostasis of the microbiome in the vagina and ectocervix plays a paramount role in reproductive health. Depending on its composition, the microbiome may protect the vagina from infectious or non-infectious diseases, or it may enhance its susceptibility to them. Because of the nature of this organ, and the fact that it is continuously colonized by bacteria from birth to death, it is virtually certain that this rich environment evolved in concert with its microbial flora. Specific interactions dictated by the genetics of both the host and microbes are likely responsible for maintaining both the environment and the microbiome. However, the genetic basis of these interactions in both the host and the bacterial colonizers is currently unknown. _Lactobacillus_ species are associated with vaginal health, but the role of these species in the maintenance of health is not yet well defined. Similarly, other species, including those representing minor components of the overall flora, undoubtedly influence the ability of potential pathogens to thrive and cause disease. Gross alterations in the vaginal microbiome are frequently observed in women with bacterial vaginosis, but the exact etiology of this disorder is still unknown. There are also implications for vaginal flora in non-infectious conditions such as pregnancy, pre-term labor and birth, and possibly fertility and other aspects of women’s health. Conversely, the role of environmental factors in the maintenance of a healthy vaginal microbiome is largely unknown. To explore these issues, we have proposed to address the following questions:

*1.	Do the genes of the host contribute to the composition of the vaginal microbiome?* We hypothesize that genes of both host and bacteria have important impacts on the vaginal microbiome. We are addressing this question by examining the vaginal microbiomes of mono- and dizygotic twin pairs selected from the over 170,000 twin pairs in the Mid-Atlantic Twin Registry (MATR). Subsequent studies, beyond the scope of the current project, may investigate which host genes impact the microbial flora and how they do so.
*2.	What changes in the microbiome are associated with common non-infectious pathological states of the host?* We hypothesize that altered physiological (e.g., pregnancy) and pathologic (e.g., immune suppression) conditions, or environmental exposures (e.g., antibiotics) predictably alter the vaginal microbiome. Conversely, certain vaginal microbiome characteristics are thought to contribute to a woman’s risk for outcomes such as preterm delivery. We are addressing this question by recruiting study participants from the ~40,000 annual clinical visits to women’s clinics of the VCU Health System.
*3.	What changes in the vaginal microbiome are associated with relevant infectious diseases and conditions?* We hypothesize that susceptibility to infectious disease (e.g. HPV, _Chlamydia_ infection, vaginitis, vaginosis, etc.) is impacted by the vaginal microbiome. In turn, these infectious conditions clearly can affect the ability of other bacteria to colonize and cause pathology. Again, we are exploring these issues by recruiting participants from visitors to women’s clinics in the VCU Health System.

Three kinds of sequence data are generated in this project: i) rDNA sequences from vaginal microbes; ii) whole metagenome shotgun sequences from vaginal samples; and iii) whole genome shotgun sequences of bacterial clones selected from vaginal samples. The study includes samples from three vaginal sites: mid-vaginal, cervical, and introital. The data sets also include buccal and perianal samples from all twin participants. Samples from these additional sites are used to test the hypothesis of a per continuum spread of bacteria in relation to vaginal health. An extended set of clinical metadata associated with these sequences are deposited with dbGAP. We have currently collected over 4,400 samples from ~100 twins and over 450 clinical participants. We have analyzed and deposited data for 480 rDNA samples, eight whole metagenome shotgun samples, and over 50 complete bacterial genomes. These data are available to accredited investigators according to NIH and Human Microbiome Project (HMP) guidelines. The bacterial clones are deposited in the Biodefense and Emerging Infections Research Resources Repository ("http://www.beiresources.org/":http://www.beiresources.org/). 

In addition to the extensive sequence data obtained in this study, we are collecting metadata associated with each of the study participants. Thus, participants are asked to complete an extensive health history questionnaire at the time samples are collected. Selected clinical data associated with the visit are also obtained, and relevant information is collected from the medical records when available. This data is maintained securely in a HIPAA-compliant data system as required by VCU’s Institutional Review Board (IRB). The preponderance of these data (i.e., that judged appropriate by NIH staff and VCU’s IRB are deposited at dbGAP ("http://www.ncbi.nlm.nih.gov/gap":http://www.ncbi.nlm.nih.gov/gap). Selected fields of this data have been identified by NIH staff as ‘too sensitive’ and are not available in dbGAP. Individuals requiring access to these data fields are asked to contact the PI of this project or NIH Program Staff. 
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    The truth about metagenomics: quantifying and counteracting bias in 16S rRNA studies

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    Background Characterizing microbial communities via next-generation sequencing is subject to a number of pitfalls involving sample processing. The observed community composition can be a severe distortion of the quantities of bacteria actually present in the microbiome, hampering analysis and threatening the validity of conclusions from metagenomic studies. We introduce an experimental protocol using mock communities for quantifying and characterizing bias introduced in the sample processing pipeline. We used 80 bacterial mock communities comprised of prescribed proportions of cells from seven vaginally-relevant bacterial strains to assess the bias introduced in the sample processing pipeline. We created two additional sets of 80 mock communities by mixing prescribed quantities of DNA and PCR product to quantify the relative contribution to bias of (1) DNA extraction, (2) PCR amplification, and (3) sequencing and taxonomic classification for particular choices of protocols for each step. We developed models to predict the “true” composition of environmental samples based on the observed proportions, and applied them to a set of clinical vaginal samples from a single subject during four visits. Results We observed that using different DNA extraction kits can produce dramatically different results but bias is introduced regardless of the choice of kit. We observed error rates from bias of over 85% in some samples, while technical variation was very low at less than 5% for most bacteria. The effects of DNA extraction and PCR amplification for our protocols were much larger than those due to sequencing and classification. The processing steps affected different bacteria in different ways, resulting in amplified and suppressed observed proportions of a community. When predictive models were applied to clinical samples from a subject, the predicted microbiome profiles were better reflections of the physiology and diagnosis of the subject at the visits than the observed community compositions. Conclusions Bias in 16S studies due to DNA extraction and PCR amplification will continue to require attention despite further advances in sequencing technology. Analysis of mock communities can help assess bias and facilitate the interpretation of results from environmental samples

    Absence of influence of gender and BMPR2 mutation type on clinical phenotypes of pulmonary arterial hypertension

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    <p>Abstract</p> <p>Background</p> <p>Previous studies indicate that patients with pulmonary arterial hypertension (PAH) carrying a mutation in the bone morphogenetic protein receptor type 2 (<it>BMPR2</it>) gene, develop the disease 10 years earlier than non-carriers, and have a more severe hemodynamic compromise at diagnosis. A recent report has suggested that this may only be the case for females and that patients with missense mutations in <it>BMPR2 </it>gene have more severe disease than patients with truncating mutations.</p> <p>Methods</p> <p>We reviewed data from all patients with PAH considered as idiopathic and patients with a family history of PAH, who underwent genetic counselling in the French PAH network between January, 1<sup>st </sup>2004 and April, 1<sup>st </sup>2010. We compared clinical, functional, and hemodynamic characteristics between carriers and non-carriers of a <it>BMPR2 </it>mutation, according to gender or <it>BMPR2 </it>mutation type.</p> <p>Results</p> <p>PAH patients carrying a <it>BMPR2 </it>mutation (n = 115) were significantly younger at diagnosis than non-carriers (n = 267) (35.8 ± 15.4 and 47.5 ± 16.2 respectively, p < 0.0001). The presence of a <it>BMPR2 </it>mutation was associated with a younger age at diagnosis in females (36.4 ± 14.9 in <it>BMPR2 </it>mutation carriers and 47.4 ± 15.8 in non-carriers, p < 0.0001), and males (34.6 ± 16.8 in <it>BMPR2 </it>mutation carriers and 47.8 ± 17.1 in non-carriers, p < 0.0001). <it>BMPR2 </it>mutation carriers had a more severe hemodynamic compromise at diagnosis, but this was not influenced by gender. No differences in survival and time to death or lung transplantation were found in male and female PAH patients carrying a <it>BMPR2 </it>mutation. No differences were observed in clinical outcomes according to the type of <it>BMPR2 </it>mutations (missense, truncating, large rearrangement or splice defect).</p> <p>Conclusion</p> <p>When compared to non-carriers, <it>BMPR2 </it>mutation carriers from the French PAH network are younger at diagnosis and present with a more severe hemodynamic compromise, irrespective of gender. Moreover, <it>BMPR2 </it>mutation type had no influence on clinical phenotypes in our patient population.</p

    First events from the CNGS neutrino beam detected in the OPERA experiment

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    The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in appearance mode, through the study of nu_mu to nu_tau oscillations. The apparatus consists of a lead/emulsion-film target complemented by electronic detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam (CNGS) 730 km away from the neutrino source. In August 2006 a first run with CNGS neutrinos was successfully conducted. A first sample of neutrino events was collected, statistically consistent with the integrated beam intensity. After a brief description of the beam and of the various sub-detectors, we report on the achievement of this milestone, presenting the first data and some analysis results.Comment: Submitted to the New Journal of Physic
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