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We reanalyze deep-inelastic scattering data of the BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We also perform the fits of high-statistic deep-inelastic scattering data of the BCDMS, SLAC, ...
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We reanalyze deep-inelastic scattering data of the BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We also perform the fits of high-statistic deep-inelastic scattering data of the BCDMS, SLAC, NM, and BFP Collaborations taking the data separately and in a combined way and find good agreement between these analyses. We extract the Values of both the QCD coupling constant alpha(s)(M-Z(2)) up to the NLO level and of the power corrections to the structure function F-2. The fits of the combined data for the nousinglet part of the structure function F-2 predict the coupling constant value sigma(s)(M-Z(2)) = 0.1174 +/- 0.0007 (stat.) +/- 0.0019 (syst.) +/- 0.0010 (norm.) (or QCD parameter Delta(5)/MS = 204 +/- 25 (total experimental error) MeV). The fits of the combined data for both the nonsinglet part ills and the singlet part lead to the values alpha(s)(M-Z(2)) 0.1177 +/- 0.0007 (stat.) +/- 0.0021 (syst.) +/- 0.0009 (norm.) (or QCD parameter Lambda(5)/MS = (208 +/- 27 (total experimental error) MeV). The above values are in very good X-Is agreement with each other. We estimate theoretical uncertainties for alpha(s)(M-Z(2)) at +0.0047 and -0.0057 from fits of the combined data when complete singlet and nonsinglet Q(2) evolution is taken into account. (c) 2005 Pleiades Publishing, Inc.
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We review the double asymptotic scaling phenomenon for the structure functions of the deep-inelastic scattering process. We present an analytical parameterization of the contributions from the twist-two operators of the Wilson ope...
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We review the double asymptotic scaling phenomenon for the structure functions of the deep-inelastic scattering process. We present an analytical parameterization of the contributions from the twist-two operators of the Wilson operator product expansion and power suppressed terms. Higher twist corrections to F-2 at small x are studied for the case of a flat initial condition for the twist-two QCD evolution in the next-to-leading order approximation. Higher twist terms are estimated using two different approaches: one motivated by BFKL and the other motivated by the renormalon formalism. The results of the latter approach are in very good agreement with deep inelastic scattering data from HERA.
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Rice bran protein concentrates prepared from superfine, fine and coarse cultivars were assessed for their physicochemical, structural, functional properties and digestibility. The protein concentrates differed in structural, therm...
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Rice bran protein concentrates prepared from superfine, fine and coarse cultivars were assessed for their physicochemical, structural, functional properties and digestibility. The protein concentrates differed in structural, thermal and functional properties. Rice bran protein concentrate of fine cultivar (F-RBPC) had relatively more beta-sheets (42.81%) and less alpha-helix (15.03%) and beta-turns (21.98%) than that of superfine (SF-RBPC) and coarse (C-RBPC) cultivars. Thermal denaturation temperature (T-d) was similar for all cultivars, whereas enthalpy of denaturation (Delta H) was high for F-RBPC. Essential and uncharged polar amino acids were the highest in F-RBPC and the lowest in C-RBPC. SF-RBPC had higher digestibility in comparison to F-RBPC and C-RBPC. Surface hydrophobicity, protein solubility and foaming capacity were greatest for F-RBPC. Whereas, SF-RBPC exhibited better foaming stability and emulsion activity and C-RBPC displayed more stable emulsion. Principal component analysis revealed that T-d and Delta H were positively correlated with beta-sheets content. Foaming capacity and protein solubility were related positively with surface hydrophobicity and negatively charged or uncharged polar amino acids. Emulsion properties were negatively correlated with hydrophobicity. In vitro digestibility of protein was negatively correlated to the ratio of Arginine to Lysine. (C) 2018 Elsevier B.V. All rights reserved.
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Cellular studies indicate that endocannabinoid type-1 retrograde signaling plays a major role in synaptic plasticity. Disruption of these processes by delta-9-tetrahydrocannabinol (THC) could produce alterations either in structur...
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Cellular studies indicate that endocannabinoid type-1 retrograde signaling plays a major role in synaptic plasticity. Disruption of these processes by delta-9-tetrahydrocannabinol (THC) could produce alterations either in structural and functional brain connectivity or in their association in cannabis (CB) users. Graph theoretic structural and functional networks were generated with diffusion tensor imaging and resting-state functional imaging in 37 current CB users and 31 healthy non-users. The primary outcome measures were coupling between structural and functional connectivity, global network characteristics, association between the coupling and network properties, and measures of rich-club organization. Structural-functional (SC-FC) coupling was globally preserved showing a positive association in current CB users. However, the users had disrupted associations between SC-FC coupling and network topological characteristics, most perturbed for shorter connections implying region-specific disruption by CB use. Rich-club analysis revealed impaired SC-FC coupling in the hippocampus and caudate of users. This study provides evidence of the abnormal SC-FC association in CB users. The effect was predominant in shorter connections of the brain network, suggesting that the impact of CB use or predispositional factors may be most apparent in local interconnections. Notably, the hippocampus and caudate specifically showed aberrant structural and functional coupling. These structures have high CB1 receptor density and may also be associated with changes in learning and habit formation that occur with chronic cannabis use.
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The gene yfdU from Escherichia coli encodes a putative oxalyl coenzyme A decarboxylase, a thiamine diphosphate-dependent enzyme that is potentially involved in the degradation of oxalate. The enzyme has been purified to homogeneit...
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The gene yfdU from Escherichia coli encodes a putative oxalyl coenzyme A decarboxylase, a thiamine diphosphate-dependent enzyme that is potentially involved in the degradation of oxalate. The enzyme has been purified to homogeneity. The kinetic constants for conversion of the substrate oxalyl coenzyme A by the enzyme in the absence and presence of the inhibitor coenzyme A, as well as in the absence and presence of the activator adenosine 5'-diphosphate, were determined using a novel continuous optical assay. The effects of these ligands on the solution and crystal structure of the enzyme were studied using small-angle X-ray scattering and X-ray crystal diffraction. Analyses of the obtained crystal structures of the enzyme in complex with the cofactor thiamine diphosphate, the activator adenosine 5'-diphosphate and the inhibitor acetyl coenzyme A, as well as the corresponding solution scattering patterns, allow comparison of the oligomer structures of the enzyme complexes under various experimental conditions, and provide insights into the architecture of substrate and effector binding sites.
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The determination of structural models of the various stable states of an ion channel is a key step toward the characterization of its conformational dynamics. In the case of nicotinic-type receptors, different structures have bee...
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The determination of structural models of the various stable states of an ion channel is a key step toward the characterization of its conformational dynamics. In the case of nicotinic-type receptors, different structures have been solved but, thus far, these different models have been obtained from different members of the super-family. In the case of the bacterial member ELIC, a cysteamine-gated channel from Erwinia chrisanthemi, a structural model of the protein in the absence of activating ligand (and thus, conceivably corresponding to the closed state of this channel) has been previously generated. In this article, electrophysiological characterization of ELIC mutants allowed;us to identify pore mutations that slow down the time course of desensitization to the extent that the channel seems not to desensitize at all for the duration of the agonist applications (>20 min). Thus, it seems reasonable to conclude that the probability of ELIC occupying the closed state is much lower for the ligand-bound mutants than for the unliganded wild-type channel. To gain insight into the conformation adopted by ELIC under these conditions, we solved the crystal structures of two of these mutants in the presence of a concentration of cysteamine that elicits an intra-cluster open probability of >0.9. Curiously, the obtained structural models turned out to be nearly indistinguishable from the model of the wild-type channel in the absence of bound agonist. Overall, our findings bring to light the limited power of functional studies in intact membranes when it comes to inferring the functional state of a channel in a crystal, at least in the case of the nicotinic-receptor superfamily.
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BACKGROUND: Recently, much attention has focused on the biological properties of fungal polysaccharides. Polysaccharides extracted from Phellinus baumii Pilat are reported to have antitumor and immunostimulatory properties, as wel...
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BACKGROUND: Recently, much attention has focused on the biological properties of fungal polysaccharides. Polysaccharides extracted from Phellinus baumii Pilat are reported to have antitumor and immunostimulatory properties, as well as anti-mutagenicity activity, hypoglycemic and free radical scavenging properties. In this paper, we report the chemical and structural characterization of a novel neutral polysaccharide isolated from the fruiting bodies of P. baumii Pilat.RESULTS: PBF4, a purified polysaccharide, was isolated from the fruiting bodies of P. baumii Pilat, and was shown to be composed of L-fucose and D-glucose in a ratio of 1:4. It was found to be a fucoglucan consisting of a alpha-(1 -> 4)-D-glucopyranose backbone with some insertions of alpha-(1 -> 2)-L-Fucp residues. It also contained a minor beta-(1 -> 4,6)-linked D-glucopyranosyl and beta-glycosidically linked nonreducing-end D-glucopyranosyl residues.CONCLUSION: Our results add a new polysaccharide to those already described for different fungal groups. This kind of polysaccharide is useful for further study of the structure-function relationships and mechanism responsible for its biological activities. (C) 2008 Society of Chemical Industry
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We examine the recent COMPASS data on the spin structure function g (1) singlet. We show that it is rather difficult to use the data in the present form in order to draw conclusions on the initial parton densities. However, our te...
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We examine the recent COMPASS data on the spin structure function g (1) singlet. We show that it is rather difficult to use the data in the present form in order to draw conclusions on the initial parton densities. However, our tentative estimate is that the data better agree with positive than with negative initial gluon densities.
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Two-dimensional nets may be used to generate the stoichiometry and structure of single-layer and double-layer sheet-silicate minerals. Many sheet-silicate minerals are based on the 3-connected plane nets 6(3), 4.8(2), (4.6.8)(2)(6...
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Two-dimensional nets may be used to generate the stoichiometry and structure of single-layer and double-layer sheet-silicate minerals. Many sheet-silicate minerals are based on the 3-connected plane nets 6(3), 4.8(2), (4.6.8)(2)(6.8(2))(1) and (5(2).8)(1)(5.8(2))(1), and some more complicated nets, e.g. (5.6.7)(4)(5.7(2))(1)(6(2).7)(1), (4.12(2))(2) (4(2).12)(1), (5(2).8)(1)(5.6(2))(1)(5.6.8)(2)(6(2).8)(1), have one or two representative structures. Many complicated sheet-silicate minerals are based on sheets of 2-, 3- and 4-connected tetrahedra that may be developed from 3- and 4-connected plane nets by a series of oikodomeic operations on 3-or 4-connected nets that change the topology of the parent net. There are three classes of oikodomeic operations: (1) insertion of 2- and 3-connected vertices into 3- and 4-connected plane nets; (2,3) replication of single-layer sheets by topological mirror or two-fold-rotation operators, and condensation of the resulting two single-layer sheets to form double-layer sheets. The topological aspects of these sheet structures may be described by functions that express stoichiometry in terms of tetrahedron connectivities (formula-generating functions) and functions that associate these formula-generating functions with specific two-dimensional nets. Using these functions, we may generate formulae and structural arrangements of single-layer and double-layer silicate structures with specific local and long-range topological features.
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Clostridial neurotoxins possess discrete structural domains with distinct pharmacological properties. Aspects of neurotoxin function with therapeutic potential include specific neuronal binding, intracellular (cytosolic) delivery ...
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Clostridial neurotoxins possess discrete structural domains with distinct pharmacological properties. Aspects of neurotoxin function with therapeutic potential include specific neuronal binding, intracellular (cytosolic) delivery of biologically active protein and inhibition of SNARE-mediated secretion. Understanding the structure function relationship of the neurotoxin protein enables the creation of recombinant proteins incorporating select domains of the neurotoxins to produce novel proteins with therapeutic potential in a range of clinical applications.
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