838 research outputs found

    Characterization of nebulized buparvaquone nanosuspensions - effect of nebulization technology

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    The poorly soluble drug buparvaquone is proposed as an alternative treatment of Pneumocystis carinii pneumonia (PCP) lung infections. Physically stable nanosuspensions were formulated in order to deliver the drug at the site of infection using nebulization. The aerosolization characteristics of two buparvaquone nanosuspensions were determined with commercial jet and ultrasonic nebulizer devices. Aerosol droplet size distribution was determined with laser diffractometry (LD). Nebulization of the nanosuspensions and dispersion media surfactant solutions produced aerosol droplets diameters in the range from 3 to 5 mu m for Respi-jet Kendall, Pari Turbo Boy system and Multisonic nebulizers and particles around 9-10 mm with Omron U1. Fractions of the nanosuspensions from the nebulizer reservoir and of aerosol produced were collected to investigate changes in the size of the drug nanocrystals influenced by the nebulization technology. Comparisons were performed measuring the drug nanocrystals with photon correlation spectroscopy (PCS) and LD of the samples. Drug particle aggregates were detected in the fractions of aerosol collected from jet nebulizers. Nebulizer technology ( jet vs. ultrasonic) showed influence on the stability of the drug particle size distribution of buparvaquone nanocrystals during the nebulization time evaluated

    Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Blood lead has been associated with an elevated risk of miscarriage. The plasmatic fraction of lead represents the toxicologically active fraction of lead. Women with a tendency to have a higher plasma/whole blood Pb ratio could tend towards an elevated risk of miscarriage due to a higher plasma Pb for a given whole blood Pb and would consequently have a history of spontaneous abortion.</p> <p>Methods</p> <p>We studied 207 pregnant Mexico City residents during the 1<sup>st </sup>trimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.</p> <p>Results</p> <p>The mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 μg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.</p> <p>Conclusion</p> <p>Women with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.</p

    An Overview of the 2014 ALMA Long Baseline Campaign

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    A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to ~15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from September to late November 2014, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at ~350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy.Comment: 11 pages, 7 figures, 2 tables; accepted for publication in the Astrophysical Journal Letters; this version with small changes to affiliation

    DNA Methylation-Independent Reversion of Gemcitabine Resistance by Hydralazine in Cervical Cancer Cells

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    BACKGROUND: Down regulation of genes coding for nucleoside transporters and drug metabolism responsible for uptake and metabolic activation of the nucleoside gemcitabine is related with acquired tumor resistance against this agent. Hydralazine has been shown to reverse doxorubicin resistance in a model of breast cancer. Here we wanted to investigate whether epigenetic mechanisms are responsible for acquiring resistance to gemcitabine and if hydralazine could restore gemcitabine sensitivity in cervical cancer cells. METHODOLOGY/PRINCIPAL FINDINGS: The cervical cancer cell line CaLo cell line was cultured in the presence of increasing concentrations of gemcitabine. Down-regulation of hENT1 & dCK genes was observed in the resistant cells (CaLoGR) which was not associated with promoter methylation. Treatment with hydralazine reversed gemcitabine resistance and led to hENT1 and dCK gene reactivation in a DNA promoter methylation-independent manner. No changes in HDAC total activity nor in H3 and H4 acetylation at these promoters were observed. ChIP analysis showed H3K9m2 at hENT1 and dCK gene promoters which correlated with hyper-expression of G9A histone methyltransferase at RNA and protein level in the resistant cells. Hydralazine inhibited G9A methyltransferase activity in vitro and depletion of the G9A gene by iRNA restored gemcitabine sensitivity. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that acquired gemcitabine resistance is associated with DNA promoter methylation-independent hENT1 and dCK gene down-regulation and hyper-expression of G9A methyltransferase. Hydralazine reverts gemcitabine resistance in cervical cancer cells via inhibition of G9A histone methyltransferase

    High voltage calibration method for the CMS RPC detector

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    The Resistive Plate Chambers (RPC) are used for muon triggers in the CMS experiment. To calibrate the high voltage working-points (WP) and identify degraded detectors due to radiation or chemical damage, a high voltage scan has been performed using 2017 data from pp collisions at a center-of-mass energy of 13 TeV. In this paper, we present the calibration method and the latest results obtained for the 2017 data. A comparison with all scans taken since 2011 is considered to investigate the stability of the detector performance in time

    CMSRPC efficiency measurement using the tag-and-probe method

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    We measure the efficiency of CMS Resistive Plate Chamber (RPC) detectors in proton-proton collisions at the centre-of-mass energy of 13 TeV using the tag-and-probe method. A muon from a Z(0) boson decay is selected as a probe of efficiency measurement, reconstructed using the CMS inner tracker and the rest of CMS muon systems. The overall efficiency of CMS RPC chambers during the 2016-2017 collision runs is measured to be more than 96% for the nominal RPC chambers

    Search for resonances in the mass spectrum of muon pairs produced in association with b quark jets in proton-proton collisions at root 8 and 13 TeV

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    A search for resonances in the mass range 12-70 GeV produced in association with a b quark jet and a second jet, and decaying to a muon pair, is reported. The analysis is based on data from proton-proton collisions at center-of-mass energies of 8 and 13 TeV, collected with the CMS detector at the LHC and corresponding to integrated luminosities of 19.7 and 35.9 fb(-1), respectively. The search is carried out in two mutually exclusive event categories. Events in the first category are required to have a b quark jet in the central region (|| 2.4) and at least one jet in the forward region (|| > 2.4). Events in the second category are required to have two jets in the central region, at least one of which is identified as a b quark jet, no jets in the forward region, and low missing transverse momentum. An excess of events above the background near a dimuon mass of 28 GeV is observed in the 8 TeV data, corresponding to local significances of 4.2 and 2.9 standard deviations for the first and second event categories, respectively. A similar analysis conducted with the 13 TeV data results in a mild excess over the background in the first event category corresponding to a local significance of 2.0 standard deviations, while the second category results in a 1.4 standard deviation deficit. The fiducial cross section measurements and 95% confidence level upper limits on those for a resonance consistent with the 8 TeV excess are provided at both collision energies

    Search for excited leptons in ℓℓγ final states in proton-proton collisions at s√=13 TeV

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    A search has been performed for heavy resonances decaying to ZZ or ZW in 2l2q final states, with two charged leptons (l = e, mu) produced by the decay of a Z boson, and two quarks produced by the decay of a W or Z boson. The analysis is sensitive to resonances with masses in the range from 400 to 4500 GeV. Two categories are defined based on the merged or resolved reconstruction of the hadronically decaying vector boson, optimized for high- and low-mass resonances, respectively. The search is based on data collected during 2016 by the CMS experiment at the LHC in proton-proton collisions with a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). No excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-1 and spin-2 resonances are derived as a function of the resonance mass, and exclusion limits on the production of W' bosons and bulk graviton particles are calculated in the framework of the heavy vector triplet model and warped extra dimensions, respectively.A search has been performed for heavy resonances decaying to ZZ or ZW in 2l2q final states, with two charged leptons (l = e, mu) produced by the decay of a Z boson, and two quarks produced by the decay of a W or Z boson. The analysis is sensitive to resonances with masses in the range from 400 to 4500 GeV. Two categories are defined based on the merged or resolved reconstruction of the hadronically decaying vector boson, optimized for high- and low-mass resonances, respectively. The search is based on data collected during 2016 by the CMS experiment at the LHC in proton-proton collisions with a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). No excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-1 and spin-2 resonances are derived as a function of the resonance mass, and exclusion limits on the production of W' bosons and bulk graviton particles are calculated in the framework of the heavy vector triplet model and warped extra dimensions, respectively.A search is presented for excited electrons and muons in final states at the LHC. The search is based on a data sample corresponding to an integrated luminosity of 35.9 fb(-1) of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector in 2016. This is the first search for excited leptons at = 13 TeV. The observation is consistent with the standard model background prediction, and the most stringent exclusion limits to date are set on the excited lepton mass and the compositeness scale, at 95% confidence level. Excited electrons and muons are excluded for masses below 3.9 and 3.8 TeV, respectively, under the assumption that the excited lepton mass equals the compositeness scale. The best observed limit on the compositeness scale is obtained with an excited lepton mass of around 1.0 TeV, excluding values below 25 TeV for both excited electrons and muons.Peer reviewe

    Measurement of exclusive Upsilon photoproduction from protons in pPb collisions at root sNN=5.02 Tev

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    An Erratum to this article was published on 20 April 2022: https://doi.org/10.1140/epjc/s10052-022-10276-2The exclusive photoproduction of (nS) meson states from protons, (nS) p (with n = 1, 2, 3), is studied in ultraperipheral pPb collisions at a centre-of-mass energy per nucleon pair of The measurement is performed using the decay mode, with data collected by the CMS experiment corresponding to an integrated luminosity of 32.6 nb(-1). Differential cross sections as functions of the nS) transverse momentum squared and rapidity y, are presented. The 1S) photoproduction cross section is extracted in the rapidity range < 2.2, which corresponds to photon-proton centre-of-mass energies in the range 91 W < 826 GeV. The data are compared to theoretical predictions based on perturbative quantum chromodynamics and to previous measurements.Peer reviewe
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