98 research outputs found
Threshold-Free Population Analysis Identifies Larger DRG Neurons to Respond Stronger to NGF Stimulation
Sensory neurons in dorsal root ganglia (DRG) are highly heterogeneous in terms of cell size, protein expression, and signaling activity. To analyze their heterogeneity, threshold-based methods are commonly used, which often yield highly variable results due to the subjectivity of the individual investigator. In this work, we introduce a threshold-free analysis approach for sparse and highly heterogeneous datasets obtained from cultures of sensory neurons. This approach is based on population estimates and completely free of investigator-set parameters. With a quantitative automated microscope we measured the signaling state of single DRG neurons by immunofluorescently labeling phosphorylated, i.e., activated Erk1/2. The population density of sensory neurons with and without pain-sensitizing nerve growth factor (NGF) treatment was estimated using a kernel density estimator (KDE). By subtraction of both densities and integration of the positive part, a robust estimate for the size of the responsive subpopulations was obtained. To assure sufficiently large datasets, we determined the number of cells required for reliable estimates using a bootstrapping approach. The proposed methods were employed to analyze response kinetics and response amplitude of DRG neurons after NGF stimulation. We thereby determined the portion of NGF responsive cells on a true population basis. The analysis of the dose dependent NGF response unraveled a biphasic behavior, while the study of its time dependence showed a rapid response, which approached a steady state after less than five minutes. Analyzing two parameter correlations, we found that not only the number of responsive small-sized neurons exceeds the number of responsive large-sized neurons—which is commonly reported and could be explained by the excess of small-sized cells—but also the probability that small-sized cells respond to NGF is higher. In contrast, medium-sized and large-sized neurons showed a larger response amplitude in their mean Erk1/2 activity
Correlation of RET somatic mutations with clinicopathological features in sporadic medullary thyroid carcinomas
Screening of REarranged during Transfection (RET) gene mutations has been carried out in different series of sporadic medullary thyroid carcinomas (MTC). RET-positive tumours seem to be associated to a worse clinical outcome. However, the correlation between the type of RET mutation and the patients' clinicopathological data has not been evaluated yet
Predição do índice de conforto térmico em edificíos de escritório na Alemanha
Ladrões internacionais indicam quais são as exigências sobre conforto térmico que devem ser alcançadas em espaços de escritório. Elas se baseiam em um modelo desenvolvido pelo Prof. Paul Ole Fanger, no Centre for Indoor Environment and Energy, na Dinamarca. Hoje, quarenta anos de pesquisa mostram uma evolução desses indicadores. Este trabalho consiste no desenvolvimento de uma ferramenta para avaliar o conforto térmico em espaços de trabalho de edifícios de escritório. A metodologia baseia-se em medições e questionários realizados no local. Para o estudo de campo utiliza-se uma unidade móvel equipada com sensores e um questionário pelos quais se obtêm respostas dos usuários sobre a qualidade térmica do ambiente de trabalho. Levantam-se as condições térmicas de trinta edifícios de escritório na Alemanha com diferentes sistemas de climatização. A correlação entre os dados objetivos e subjetivos permite desenvolver uma fórmula que calcula o nível de insatisfação térmica em um ambiente determinado, em função de aspectos locais. Para os edifícios estudados, a temperatura de conforto é 23,3 ºC e o percentual mínimo de usuários insatisfeitos é de 7%, sendo 2,3 K (Kelvin) menor que o modelo de Fanger, o que é significativo no balanço energético dos edifícios localizados em um clima da Europa central
Measurement of the differential and total cross sections of the γd→K0Λ(p) reaction within the resonance region
We report the first measurement of differential and total cross sections for
the reaction, using data from the CLAS detector
at the Thomas Jefferson National Accelerator Facility. Data collected during
two separate experimental runs were studied with photon-energy coverage 0.8 -
3.6 GeV and 0.5 - 2.6 GeV, respectively. The two measurements are consistent
giving confidence in the method and determination of systematic uncertainties.
The cross sections are compared with predictions from the KAON-MAID theoretical
model (without kaon exchange), which deviate from the data at higher W and at
forward kaon angles. These data, along with previously published cross sections
for photoproduction, provide essential constraints on the
nucleon resonance spectrum. A first partial wave analysis has been performed
that describes the data without the introduction of new resonances.Comment: 18 pages, 16 figures and data tabl
Determination of the proton spin structure functions for 0.05 < Q(2) < 5GeV(2) using CLAS
International audienceWe present the results of our final analysis of the full data set of g1p(Q2), the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000–2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets (NH315 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries A1p and A2p and spin structure functions g1p and g2p over a wide kinematic range (0.05 GeV2<Q2< 5 GeV2 and 1.08 GeV <W< 3 GeV) and calculated moments of g1p. We compare our final results with various theoretical models and expectations, as well as with parametrizations of the world data. Our data, with their precision and dense kinematic coverage, are able to constrain fits of polarized parton distributions, test pQCD predictions for quark polarizations at large x, offer a better understanding of quark-hadron duality, and provide more precise values of higher twist matrix elements in the framework of the operator product expansion
Photon beam asymmetry Sigma for eta and eta ' photoproduction from the proton
Measurements of the linearly-polarized photon beam asymmetry for
photoproduction from the proton of and mesons are
reported. A linearly-polarized tagged photon beam produced by coherent
bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF
Large Acceptance Spectrometer. Results are presented for the reaction for incident photon energies from 1.070 to 1.876 GeV, and from
1.516 to 1.836 GeV for the reaction. For , the data reported here considerably extend the range of
measurements to higher energies, and are consistent with the few previously
published measurements for this observable near threshold. For , the results obtained are consistent with the few previously
published measurements for this observable near threshold, but also greatly
expand the incident photon energy coverage for that reaction. Initial analysis
of the data reported here with the Bonn-Gatchina model strengthens the evidence
for four nucleon resonances -- the , ,
and resonances -- which presently lack the
"four-star" status in the current Particle Data Group compilation, providing
examples of how these new measurements help refine models of the
photoproduction process.Comment: 10 pages, 3 figure
Semi-inclusive pi(0) target and beam-target asymmetries from 6 GeV electron scattering with CLAS
We present precision measurements of the target and beam-target spin
asymmetries from neutral pion electroproduction in deep-inelastic scattering
(DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We
scattered 6-GeV, longitudinally polarized electrons off longitudinally
polarized protons in a cryogenic NH target, and extracted double and
single target spin asymmetries for in
multidimensional bins in four-momentum transfer ( GeV),
Bjorken- (), hadron energy fraction (), transverse
pion momentum ( GeV), and azimuthal angle between the
lepton scattering and hadron production planes. We extracted asymmetries as a
function of both and , which provide access to transverse-momentum
distributions of longitudinally polarized quarks. The double spin asymmetries
depend weakly on . The moments are zero within
uncertainties, which is consistent with the expected suppression of the Collins
fragmentation function. The observed moments suggest that quark
gluon correlations are significant at large .Comment: 18 preprint pages, 3 figure
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