277 research outputs found
Tailoring of Polarizing Agents in the bTurea Series for Cross-Effect Dynamic Nuclear Polarization in Aqueous Media
Hsp56 protein and mRNA distribution in normal and stressed P.lividus embryos
It was previously demonstrated that Paracentrotus lividus Hsp56 mitochondrial chaperonin is con-
stitutively expressed during development, that it increases after heat-shock and cadmium treatment, and that it
has a speci\ufb01c territorial distribution, both in normal and heat-shocked embryos, as shown by immunolocalization
experiments. In this work, we analyzed by Western blot the territorial distribution of the protein in plutei exposed
to heat-shock or sublethal cadmium concentrations, and we found that Hsp56 increases in both ectodermal and en-
dodermal cells. Moreover, by \u201cin situ\u201d hybridization, we looked at Hsp56 mRNA during normal development and
under stress conditions. We found that the territorial distribution of the messenger changes during development
and that its amount is steadily increased in stressed embryos. Finally, by T1 RNase assay, we identi\ufb01ed a cytoplasmic
factor that binds to the region of Hsp56 messenger containing the 5\u2019UT
Intracellular calcium accumulation and responsiveness to progesterone in capacitating human spermatozoa.
Polarization Asymmetry In The Photodisintegration Of The Deuteron
The reaction ²(γ,p)n has been studied using a monochromatic and polarized gamma ray beam at energies E(γ)=19.8, 29.0, 38.6, and 60.8 MeV. The beam of an intensity ∼4×10⁵ γ/sec was obtained by Compton back scattering of mode-locked laser light off electron bunches in the Adone storage ring. Photoneutron yields were measured at nine neutron angles thetan≃15, 30, 45, 60, 90, 120, 135, 150, and 165 deg in the center of mass (c.m.) for E(γ)=19.8, 29.0, and 38.6 MeV, and at thetan≃30, 60, 90, 120, and 150 deg c.m. for E(γ)=60.8 MeV. The polarization independent component Iₒ(theta) of the differential cross section and the polarization dependent component PI₁(theta) were deduced and the angular distribution of the azimuthal asymmetry factor Σ(theta)=I₁(theta)/Iₒ(theta) was obtained. An extensive comparison with theory has been carried out and the inclusion of corrections due to meson exchange currents and to Δ-isobar configurations have been shown to be mandatory at energies E(γ)≳40 MeV. Theoretical and experimental implications of intermediate energy deuteron photo- disintegration studies are discussed in some detail
Assessment of nutritional status and bone health in neurologically impaired children: a challenge in pediatric clinical practice
NTRODUCTION: neurologically impaired children frequently experience nutritional disorders and bone health complications. Our aim was firstly to analyze a method to interpret bone mineral density (BMD) accurately in neurologically impaired children. Secondly, to determine its relationship with the nutritional status and micronutrient levels in order to identify which factors are associated with low BMD. METHODS: a observational multicenter study was conducted in children with moderate-to-severe neurological impairment. Data collected included: medical records, anthropometric measures, hematologic and biochemical evaluation. BMD was measured with Dual-energy X-ray absorptiometry and z-scores were calculated adjusting for sex and chronological age. Secondly, BMD z-scores were calculated applying height age (age at which the child's height would be in 2nd percentile) instead of chronological age. RESULTS: fifty-two children were included (aged 4-16 years). Seventeen patients (32.7%) received feeding by gastrostomy tube. Height and BMI z-score were below 2SD in 64% and 31% of patients respectively, with normal mid upper arm circumference and skinfold thickness measurements. Low vitamin-D levels were found in 42% of cases. 50% of patients evidenced low BMD when calculated for chronological age, whereas only 34.5% showed BMD z-score <-2 when calculated for height age. No correlation was observed between BMD and vitamin-D levels, weight and height z-scores or age when BMD was calculated applying height age. CONCLUSIONS: the prevalence of low BMD is high in neurologically impaired children, and it is probably multifactorial. In these children, we suggest adjusting BMD for height age, in order not to over diagnose low BMD
The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system
We describe the electromagnetic calorimeter built for the GRAAL apparatus at
the ESRF. Its monitoring system is presented in detail. Results from tests and
the performance obtained during the first GRAAL experiments are given. The
energy calibration accuracy and stability reached is a small fraction of the
intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method
Deuteron photo-disintegration with polarised photons in the energy range 30 - 50 MeV
The reaction d(\vec\gamma,np) has been studied using the tagged and polarised
LADON gamma ray beam at an energy 30 - 50 MeV to investigate the existence of
narrow dibaryonic resonances recently suggested from the experimental
measurements in a different laboratory. The beam was obtained by Compton
back-scattering of laser light on the electrons of the storage ring ADONE.
Photo-neutron yields were measured at five neutron angle \vartheta_n = 22,
55.5, 90, 125 and 157 degrees in the center of mass system.Our results do not
support the existence of such resonances.Comment: 16 pages, Latex, 22 figures, 1 table. Nucl. Phys. A to appea
Enhanced Intersystem Crossing and Transient Electron Spin Polarization in a Photoexcited Pentacene-Trityl Radical
Limits on light-speed anisotropies from Compton scattering of high-energy electrons
The possibility of anisotropies in the speed of light relative to the
limiting speed of electrons is considered. The absence of sidereal variations
in the energy of Compton-edge photons at the ESRF's GRAAL facility constrains
such anisotropies representing the first non-threshold collision-kinematics
study of Lorentz violation. When interpreted within the minimal Standard-Model
Extension, this result yields the two-sided limit of 1.6 x 10^{-14} at 95%
confidence level on a combination of the parity-violating photon and electron
coefficients kappa_{o+} and c. This new constraint provides an improvement over
previous bounds by one order of magnitude.Comment: 4 pages, 4 figure
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