701 research outputs found
Successional blooms of alkenone-producing haptophytes in Lake George, North Dakota: Implications for continental paleoclimate reconstructions
Method validation of nanoparticle tracking analysis to measure pulmonary nanoparticle content: the size distribution in exhaled breath condensate depends on occupational exposure
A particle exposure assessment based on the dose deposited in the lungs would be the gold standard for the evaluation of any resulting health effects. Measuring particles in exhaled breath condensate (EBC)-a matrix containing water and airway lining fluid-could help to evaluate particle retention in the lungs. This study aimed to (1) validate a nanoparticle tracking analysis (NTA) method for determining the particle number concentration and their hydrodynamic size distribution in EBC, and (2) apply this method to EBC collected from workers exposed to soapstone (n = 55) or quartz dust (n = 12) and controls (n = 11). A standard latex bead solution was used to determine the linear range, limit of detection (LOD), repeatability (coefficient of variation, CV), and bias in spiked EBC. An LM10 NanoSight instrument with NTA version 3.1 software was used for measurement. RTubes(Âź) were used for field collection of EBC. The repeatability obtained for a D50 size distribution in EBC showed less than 8% variability, with a bias <7%. The particle concentration was linear in the range â€2.5 Ă 10(8) particles ml(-1) with a LOD of 4 Ă 10(6) particles ml(-1). A recovery of 117 ± 20% at 6.2 Ă 10(7) particles ml(-1) was obtained with a CV <10% and a bias <20%. EBC from workers exposed to quartz, who experienced the largest exposure to silica particles, consistently exhibited a statistically significant (p < 0.01) higher concentration of particles in their EBC, with a size distribution shift towards larger values than the other groups. Results showed that the NTA technique performed well for characterizing the size distribution and concentrations of particles in EBC. The technique needs to be corroborated with a larger population of workers
Characterization of human mesenchymal stem cells from Ewing sarcoma patients. Pathogenetic implications
Ewing Sarcoma (EWS) is a mesenchymal-derived tumor that generally arises in bone and soft tissue. Intensive research regarding the pathogenesis of EWS has been insufficient to pinpoint the early events of Ewing sarcomagenesis. However, the Mesenchymal Stem Cell (MSC) is currently accepted as the most probable cell of origin
Interface Scaling in the Contact Process
Scaling properties of an interface representation of the critical contact
process are studied in dimensions 1 - 3. Simulations confirm the scaling
relation beta_W = 1 - theta between the interface-width growth exponent beta_W
and the exponent theta governing the decay of the order parameter. A scaling
property of the height distribution, which serves as the basis for this
relation, is also verified. The height-height correlation function shows clear
signs of anomalous scaling, in accord with Lopez' analysis [Phys. Rev. Lett.
83, 4594 (1999)], but no evidence of multiscaling.Comment: 10 pages, 9 figure
ESMO Clinical Research Observatory (ECRO): improving the efficiency of clinical research through rationalisation of bureaucracy
During the last years, there has been a dramatic increase in the administrative and bureaucratic burden associated with cli
Efeito da aplicação de silicato de cĂĄlcio em Brachiaria rizantha cv. Marandu sobre a população de ninfas do percevejo castanho das raĂzes Scaptocoris carvalhoi Becker, 1967, caracterĂsticas quĂmicas do solo, planta e produção de matĂ©ria seca
Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method
This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within of the
true values and the fractional energy resolution is . The value of the ratio
obtained for the electromagnetic compartment of the combined calorimeter is
and agrees with the prediction that for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM
Comparative study of sustained-release lipid microparticles and solid dispersions containing ibuprofen
SELECTION OF EUCALYPTUS CLONES AND ADJUSTMENT OF POTASSIUM DOSES FOR EXTENDED DROUGHT IN BAHIA SAVANNA
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