338 research outputs found

    A study of the relationship between auditory analysis and growth of language art skills

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    Thesis (M.A.)--Boston University, 1942. This item was digitized by the Internet Archive

    Native foods from Brazilian biodiversity as a source of bioactive compounds

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    AbstractThe interest in South American native plant species has been growing in recent years due to their health benefits. Brazil is one of the world's mega-diverse locations with over 40,000 different plant species representing 20% of the world's flora. The country was visited in the 19th century by European travelers and naturalists, who described the use of native plant species as food. In this study, data on 67 species was recovered from historical documents and bibliographies. Several of the recorded species show potential as functional food in laboratory studies. Other species are unknown or not yet submitted to any study, in order to verify their health benefits

    Excitatory amino acids and intracellular pH in motoneurons of the isolated frog spinal cord

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    Double-barrelled pH-sensitive micro-electrodes were used to measure changes of intracellular and extracellular pH in and around motoneurons of the isolated frog spinal cord during application of excitatory amino acids. It was found that N-methyl- -aspartate, quisqualate and kainate produced a concentration-dependent intracellular acidification. Extracellularly, triphasic pH changes (acid-alkaline-acid going pH transients) were observed during the action of these amino acids. The possible significance of such pH changes for the physiological and pathophysiological effects of excitatory amino acids are discussed

    Energy consumption and capacity utilization of galvanizing furnaces

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    An explicit equation leading to a method for improving furnace efficiency is presented. This equation is dimensionless and can be applied to furnaces of any size and fuel type for the purposes of comparison. The implications for current furnace design are discussed. Currently the technique most commonly used to reduce energy consumption in galvanizing furnaces is to increase burner turndown. This is shown by the analysis presented here actually to worsen the thermal efficiency of the furnace, particularly at low levels of capacity utilization. Galvanizing furnaces are different to many furnaces used within industry, as a quantity of material (in this case zinc) is kept molten within the furnace at all times, even outside production periods. The dimensionless analysis can, however, be applied to furnaces with the same operational function as a galvanizing furnace, such as some furnaces utilized within the glass industry. © IMechE 2004

    Microarray and pathway analysis reveals decreased CDC25A and increased CDC42 associated with slow growth of BCL2 overexpressing immortalized breast cell line

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    Bcl-2 is an anti-apoptotic protein that is frequently overex-pressed in cancer cells but its role in carcinogenesis is not clear. We are interested in how Bcl-2 expression affects non-cancerous breast cells and its role in the cell cycle. We prepared an MCF10A breast epithelial cell line that stably overexpressed Bcl-2. We analyzed the cells by flow cytometry after synchronization, and used cDNA microarrays with quantitative reverse-transcription PCR (qRTPCR) to determine differences in gene expression. The microarray data was subjected to two pathway analysis tools, parametric analysis of gene set enrichment (PAGE) and ingenuity pathway analysis (IPA), and western analysis was carried out to determine the correlation between mRNA and protein levels. The MCF10A/Bcl-2 cells exhibited a slow-growth phenotype compared to control MCF10A/Neo cells that we attributed to a slowing of the G1-S cell cycle transition. A total of 363 genes were differentially expressed by at least two-fold, 307 upregulated and 56 downregulated. PAGE identified 22 significantly changed gene sets. The highest ranked network of genes identified by IPA contained 24 genes. Genes that were chosen for further analysis were confirmed by qRT-PCR, however, the western analysis did not always confirm differential expression of the proteins. Downregulation of the phosphatase CDC25A could solely be responsible for the slow growth pheno-type in MCF10A/Bcl-2 cells. Increased levels of GTPase Cdc42 could be adding to this effect. PAGE and IPA are valuable tools for microarray analysis, but protein expression results do not always follow mRNA expression results. Originally published Cell Cycle, Vol. 7, No. 19, Oct. 200

    2s1/2 occupancies in 30Si, 31P, and 32S

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    Elastic electron scattering off Si-30 and P-31 was studied in an effective momentum-transfer range of 1.8-3.0 fm(-1). The form-factor data were analyzed together with existing data sets for these nuclei and for S-32 in a model-independent Fourier-Bessel expansion. For P-31 the M1 contribution was subtracted following an established parametrization. Results of Hartree-Fock (HF) calculations, performed for these three nuclei in a spherical basis and in an axially deformed basis, are compared to experiment. Occupancies have been determined which, when used in the spherical-basis HF calculations, lead to a good description of the elastic form-factor data. The deformed-basis calculations have been used to study the influence of the deformation on the calculated binding energies and ground-state charge densities. In all calculations the influence of using different effective nucleon-nucleon interactions was investigated. The resulting differences in 2s(1/2) in occupancy are combined with results from previous existing (e,e'p) experiments to yield ''absolute occupancies'' for the 2s(1/2) orbital. The deduced 2s(1/2) occupancies for Si-30 and S-32 are 0.24(4) and 1.35(19), respectively.Peer reviewe

    Competing electric and magnetic excitations in backward electron scattering from heavy deformed nuclei

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    Important E2E2 contributions to the (e,e)(e,e^{\prime}) cross sections of low-lying orbital M1M1 excitations are found in heavy deformed nuclei, arising from the small energy separation between the two excitations with IπK=2+1I^{\pi}K = 2^+1 and 1+1^+1, respectively. They are studied microscopically in QRPA using DWBA. The accompanying E2E2 response is negligible at small momentum transfer qq but contributes substantially to the cross sections measured at θ=165\theta = 165 ^{\circ} for 0.6<qeff<0.90.6 < q_{\rm eff} < 0.9 fm1^{-1} (40Ei7040 \le E_i \le 70 MeV) and leads to a very good agreement with experiment. The electric response is of longitudinal C2C2 type for θ175\theta \le 175 ^{\circ} but becomes almost purely transverse E2E2 for larger backward angles. The transverse E2E2 response remains comparable with the M1M1 response for qeff>1.2q_{\rm eff} > 1.2 fm1^{-1} (Ei>100E_i > 100 MeV) and even dominant for Ei>200E_i > 200 MeV. This happens even at large backward angles θ>175\theta > 175 ^{\circ}, where the M1M1 dominance is limited to the lower qq region.Comment: RevTeX, 19 pages, 8 figures included Accepted for publication in Phys Rev

    High-energy scissors mode

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    All the orbital M1 excitations, at both low and high energies, obtained from a rotationally invariant QRPA, represent the fragmented scissors mode. The high-energy M1 strength is almost purely orbital and resides in the region of the isovector giant quadrupole resonance. In heavy deformed nuclei the high-energy scissors mode is strongly fragmented between 17 and 25 MeV (with uncertainties arising from the poor knowledge of the isovector potential). The coherent scissors motion is hindered by the fragmentation and B(M1)<0.25  μN2B(M1) < 0.25 \; \mu^2_N for single transitions in this region. The (e,e)(e,e^{\prime}) cross sections for excitations above 17 MeV are one order of magnitude larger for E2 than for M1 excitations even at backward angles.Comment: 20 pages in RevTEX, 5 figures (uuencoded,put with 'figures') accepted for publication in Phys.Rev.
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