1,033 research outputs found
The volume fraction of brain ventricles to total brain volume: a computed tomography stereological study
This study has been designed to estimate the volume fraction of the brain
ventricles volume to total brain volume and to correlate them with gender and
age in normal subjects. Cranial computed tomography (CT) images of 80 normally
evaluated subjects (five female and five male for each decade) were selected
from 1,073 CT examinations. The volumes of total brain, cerebral aqueduct,
fourth, third, and lateral ventricles and their ratios were estimated using
the Cavalieri method and volume fraction-stereological methods. The ratio of
total brain ventricle volume to total brain volume was comparable between
the two genders (p > 0.05, independent t test). Mean volume fraction of total
ventricle volume to total brain volume was found to be 1.21% in the first and
3.37% in the last decades. Mean volume fraction was found to increase significantly
with age (p < 0.01, r = 0.630, Pearson). In conclusion, the mean percentage
of total ventricle volume within the total brain volume was found to
be 2%. We demonstrated the volume fraction of total ventricle to total brain in
normal subjects. Total ventricle volume to total brain volume fractions can be
important tools in determining ventricle volumes, which denote variability in some
diseases (Alzheimer, schizophrenia, neurodegenerative disorders, etc.) and can
be estimated by stereological methods. (Folia Morphol 2010; 69, 4: 193-200
Differential cross section for neutron-proton bremsstrahlung
The neutron-proton bremsstrahlung process is known to be
sensitive to meson exchange currents in the nucleon-nucleon interaction. The
triply differential cross section for this reaction has been measured for the
first time at the Los Alamos Neutron Science Center, using an intense, pulsed
beam of up to 700 MeV neutrons to bombard a liquid hydrogen target. Scattered
neutrons were observed at six angles between 12 and 32, and the
recoil protons were observed in coincidence at 12, 20, and
28 on the opposite side of the beam. Measurement of the neutron and
proton energies at known angles allows full kinematic reconstruction of each
event. The data are compared with predictions of two theoretical calculations,
based on relativistic soft-photon and non-relativistic potential models.Comment: 5 pages, 3 figure
Synthesis of solid solutions of Cd1-xZnxS nanocrystals in the channels of mesostructured silica films
In this contribution, we introduce the use of metal ion (Cd(ii) and Zn(ii)) modified mesostructured silica as a reaction medium, to produce a solid solution of Cd1-xZnxS nanocrystals as a thin film. With this approach, a true liquid crystalline templating (TLCT) and liquid crystalline mesophase of transition metal salt oligo(ethylene oxide) non-ionic surfactant (((1 - x)[Cd(H2O)4](NO3)2 + x[Zn(H2O)6](NO3)2) CH 3(CH2)11(OCH2CH2) 10OH, (MLC)), systems were collectively used to synthesise mesostructured silica films. The film samples were reacted at room temperature (RT) in an H2S atmosphere to produce zinc blend Cd 1-xZnxS nanocrystals in the channels of mesostructured silica. The initial Zn(ii) and Cd(ii) ion concentrations in the reaction media determine the final composition and band gap of the Cd1-xZn xS nanocrystals. The growth process of the Cd1-xZn xS nanocrystals in the pores is influenced by the silica walls. If the walls are rigid (well polymerized, obtained by aging the samples before H2S treatment), then the Cd1-xZnxS nanoparticles are smaller in size and more uniform in size distribution. © The Royal Society of Chemistry 2006
The Charge Form Factor of the Neutron at Low Momentum Transfer from the Reaction
We report new measurements of the neutron charge form factor at low momentum
transfer using quasielastic electrodisintegration of the deuteron.
Longitudinally polarized electrons at an energy of 850 MeV were scattered from
an isotopically pure, highly polarized deuterium gas target. The scattered
electrons and coincident neutrons were measured by the Bates Large Acceptance
Spectrometer Toroid (BLAST) detector. The neutron form factor ratio
was extracted from the beam-target vector asymmetry
at four-momentum transfers , 0.20, 0.29 and 0.42
(GeV/c).Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let
Measurement of the proton electric to magnetic form factor ratio from \vec ^1H(\vec e, e'p)
We report the first precision measurement of the proton electric to magnetic
form factor ratio from spin-dependent elastic scattering of longitudinally
polarized electrons from a polarized hydrogen internal gas target. The
measurement was performed at the MIT-Bates South Hall Ring over a range of
four-momentum transfer squared from 0.15 to 0.65 (GeV/c).
Significantly improved results on the proton electric and magnetic form factors
are obtained in combination with previous cross-section data on elastic
electron-proton scattering in the same region.Comment: 4 pages, 2 figures, submitted to PR
Rheological Behaviour of an Insoluble Lemon Fibre as Affected by Stirring, Temperature, Time and Storage
The final
publication is available at link.springer.comIn this work, the effect the preparation method (two different stirring systems at two temperatures and times), fibre concentration (between 2% and 3%), temperature (between 10 °C and 50 °C) and storage time (between 24 h and 50 days at 5 °C) had on the flow properties of a suspension of dietary lemon fibre prepared with a 45° Brix sucrose solution were evaluated. This information will be helpful in order to discover the best possibilities of using fibre to increase the viscosity of certain kinds of products, depending on the processing, storage and consumption conditions. The obtained results indicate that all the aspects which contribute to increase component solubilisation and the interaction of the insoluble fraction with the aqueous phase when preparing the suspension, such as a decrease in particle size, a rise in temperature or a longer homogenization time, entail a higher apparent viscosity. Moreover, favoring the solubilisation in the preparation process leads to a more stable rheological behaviour of the suspension during storage. As expected, the apparent viscosity of suspensions was dependent on the shear rate, concentration and temperature. A thixotropic behaviour of fibre suspension was only observed at a very low shear rate (5 s -1). © 2010 Springer Science + Business Media, LLC.CĂłrdoba Sequeira, A.; Camacho Vidal, MM.; MartĂnez Navarrete, N. (2012). Rheological Behaviour of an Insoluble Lemon Fibre as Affected by Stirring, Temperature, Time and Storage. Food and Bioprocess Technology. 5(3):1083-1092. doi:10.1007/s11947-010-0478-2S1083109253Akdogan, H., & McHugh, T.-H. (2000). Flow characterization of peach products during extrusion. Food Engineering and Physical Properties, 65(3), 471â475.Alonso, M.-L., LarrodĂ©, O., & Zapico, J. (1995). Rheological behaviour of infant foods. Journal of Texture Studies, 26, 193â202.Duran, L., & Costell, E. (1982). Rheology of apricot puree: Characterization of flow. Journal of Texture Studies, 13, 43â58.Flint O (1996) MicroscopĂa de los alimentos. Manual de mĂ©todos prĂĄcticos utilizando la miscroscopĂa Ăłptica. Ed. Acribia S-A, Zaragoza, 28, 108â111Grigelmo-Miguel, N., Gorinstein, S., & MartĂn-Belloso, O. (1999a). Characterisation of peach dietary fiber concentrate as food ingredient. Food Chemistry, 65, 175â181.Grigelmo-Miguel, N., Ibarz-Ribas, A., & MartĂn-Belloso, O. (1999b). Rheology of peach dietary fibre suspensions. Journal of Food Engineering, 39, 91â99.Guerrero S-N & Alzamora S-M. (1998). Effect of pH, temperature and glucose addition on flow behaviour of fruit purĂ©es: II. Peach, papaya and mango purĂ©es. Journal of Food Engineering, 37, 77â101.Guillon, F., & Champ, M. (2000). Structural and physical properties of dietary fibres, and consequences of processing on human physiology. Food Research International, 33, 233â245.Hahn, S.-J., Ree, T., & Eyring, G.-H. (1959). Flow mechanism of thixotropic substances. Industrial and Engineering Chemistry Research, 51, 856â857.Jongaroontaprangsee, S., Tritrong, W., & Chokanaporn, W. (2007). Effects of drying temperature and particle size on hydration properties of dietary fiber powder from lime and cabbage by-products. International Journal of Food Properties, 10, 887â897.Lario, Y., Sendra, E., Garcıa-Perez, J., Fuentes, C., Sayas-Barbera, E., FernĂĄndez-LĂłpez, J., et al. (2004). Preparation of high dietary fiber powder from lemon juice by-products. Innovation of Food Science Emerging Technologies, 5, 113â117.Mahmoud M-I & Fugitt M (1996) Rheological properties of a calorically dense nutritional supplement as a function of nitrogen source and dietary fiber. In: IFT Annual Meeting. Book of Abstracts. 80A-26, 183Mizrahi, S. (1979). A review of the physicochemical approach to the analysis of the structural viscosity of fluid fruit products. Journal of Texture Studies, 10, 67â82.Paredes, M.-D.-C., Rao, M.-A., & Bourne, M.-C. (1998). Rheological characterization of salad dressings: 1. Steady shear, thixotropy and effect of temperature. Journal of Texture Studies, 19, 247â258.Raghavendra, S.-N., Ramachandra Swamy, S.-R., Rastogi, N.-K., Raghavarao, K.-S.-M.-S., Kumar, S., & Tharanathan, R.-N. (2006). Grinding characteristics and hydration properties of coconut residue: A source of dietary fiber. Journal of Food Engineering, 72, 281â286.Sakata, T., & Saito, M. (2007). Insoluble dietary fiber of wheat bran increased viscosity of pig whole cecal contents in vitro. Journal of Nutrition Science and Vitaminology, 53(4), 380â381.Saldaña, S., MartĂnez-Navarrete, N., & Chiralt, A. (2000). CaracterizaciĂłn ReolĂłgica de Alimentos de alta viscosidad. In P. Fito, A. Chiralt, A. AndrĂ©s, & N. MartĂnez-Navarrete (Eds.), Series de Ciencia e IngenierĂa de Alimentos. InvestigaciĂłn del postgrado del IAD-DTA. Vol I (p. 383). Valencia: Editorial de la Universidad PolitĂ©cnica de Valencia.Sangnark, A., & Noomhorm, A. (2003). Effect of particle sizes on functional properties of dietary fibre prepared from sugarcane bagasse. Food Chemistry, 80(2), 221â229
Polarised Quark Distributions in the Nucleon from Semi-Inclusive Spin Asymmetries
We present a measurement of semi-inclusive spin asymmetries for positively
and negatively charged hadrons from deep inelastic scattering of polarised
muons on polarised protons and deuterons in the range 1
GeV. Compared to our previous publication on this subject, with the new
data the statistical errors have been reduced by nearly a factor of two.
From these asymmetries and our inclusive spin asymmetries we determine the
polarised quark distributions of valence quarks and non-strange sea quarks at
=10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised
valence quark distribution, , is negative and the non-strange
sea distribution, , is consistent with zero over the measured
range of . We find for the first moments , and
, where we assumed
. We also determine for the first time the
second moments of the valence distributions .Comment: 17 page
Nanoscale potassium niobate crystal structure and phase transition
Nanoscale potassium niobate (KNbO3) powders of orthorhombic structure were synthesized using the sol-gel method. The heat-treatment temperature of the gels had a pronounced effect on KNbO3 particle size and morphology. Field emission scanning electron microscopy and transmission electron microscopy were used to determine particle size and morphology. The average KNbO3 grain size was estimated to be less than 100 nm, and transmission electron microscopy images indicated that KNbO3 particles had a brick-like morphology. Synchrotron X-ray diffraction was used to identify the room-temperature structures using Rietveld refinement. The ferroelectric orthorhombic phase was retained even for particles smaller than 50 nm. The orthorhombic to tetragonal and tetragonal to cubic phase transitions of nanocrystalline KNbO3 were investigated using temperature-dependent powder X-ray diffraction. Differential scanning calorimetry was used to examine the temperature dependence of KNbO3 phase transition. The Curie temperature and phase transition were independent of particle size, and Rietveld analyses showed increasing distortions with decreasing particle size
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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