bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fatigue in stroke rehabilitation patients: a pilot study
Authors: Chestnut Thomas John 
Published: May 2010

AbstractBackground and Purpose. Stroke is the leading cause of adult disability. Rehabilitation is a vital component of post‐stroke care with two‐thirds of survivors requiring rehabilitation. Fatigue is a common issue affecting stroke patients and is a barrier to rehabilitation causing inefficient care provision and potential limitation to patient recovery. No study to date has investigated whether the experience of fatigue is different between the two main causes of ischemic stroke: small‐vessel (SVD) and large‐vessel disease (LVD). The aim of the present study is to complete a pilot study to inform the feasibility, design, magnitude of difference in experience of fatigue, and sample size for a definitive study to evaluate differences in fatigue between these two groups of stroke patients. The experimental hypothesis is that participants with LVD experience a significantly greater level of fatigue than those with SVD as assessed by the Fatigue Severity Scale (FSS). Methods. The study used a cohort observational design. Thirteen participants were recruited over a two‐month period from King's College Hospital. Participants were visited on average at the start of the second week of rehabilitation to complete the FSS. An independent t‐test and ANCOVA were performed. For all statistical analyses, a significance level of p < 0.05 was used. Results. The study demonstrated a trend towards LVD participants reporting higher fatigue scores than SVD participants, even when controlling for age, with gender having no confounding effect. Conclusions. Fatigue is common amongst ischemic stroke rehabilitation participants with 85% of the combined sample experiencing fatigue at the start of the second week. The results demonstrate a trend towards LVD participants experiencing greater fatigue. While the results were non‐significant, the study demonstrates a feasible methodology which could help lay the groundwork for future research. Copyright © 2010 John Wiley & Sons, Ltd.
Evidence for specific subunit distribution and interactions in the quaternary structure of α‐crystallin
Authors: Morris Amie M. , Aquilina J. Andrew 
Published: May 2010

AbstractThe quaternary structure of α‐crystallin is dynamic, a property which has thwarted crystallographic efforts towards structural characterization. In this study, we have used collision‐induced dissociation mass spectrometry to examine the architecture of the polydisperse assemblies of α‐crystallin. For total α‐crystallin isolated directly from fetal calf lens using size‐based chromatography, the αB‐crystallin subunit was found to be preferentially dissociated from the oligomers, despite being significantly less abundant overall than the αA‐crystallin subunits. Furthermore, upon mixing molar equivalents of purified αA‐ and αB‐crystallin, the levels of their dissociation were found to decrease and increase, respectively, with time. Interestingly though, dissociation of subunits from the αA‐ and αB‐crystallin homo‐oligomers was comparable, indicating that strength of the αA:αA, and αB:αB subunit interactions are similar. Taken together, these data suggest that the differences in the number of subunit contacts in the mixed assemblies give rise to the disproportionate dissociation of αB‐crystallin subunits. Limited proteolysis mass spectrometry was also used to examine changes in protease accessibility during subunit exchange. The C‐terminus of αA‐crystallin was more susceptible to proteolytic attack in homo‐oligomers than that of αB‐crystallin. As subunit exchange proceeded, proteolysis of the αA‐crystallin C‐terminus increased, indicating that in the hetero‐oligomeric form this tertiary motif is more exposed to solvent. These data were used to propose a refined arrangement for the interactions of the α‐crystallin domains and C‐terminal extensions of subunits within the α‐crystallin assembly. In particular, we propose that the palindromic IPI motif of αB‐crystallin gives rise to two orientations of the C‐terminus. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Antiprotozoal activity of drimane and coloratane sesquiterpenes towards Trypanosoma brucei rhodesiense and Plasmodium falciparum in vitro
Authors: Wube Abraham Abebe , Bucar Franz , Gibbons Simon , Asres Kaleab , Rattray Lauren , Croft Simon L. 
Published: May 2010

AbstractThe extracts and 12 sesquiterpenes obtained from the East African medicinal plant Warburgia ugandensis Sprague (Canellaceae) were assessed for their antiplasmodial activity against the chloroquine‐sensitive (3D7) and chloroquine‐resistant (K1) strains of Plasmodium falciparum and antitrypanosomal activity against Trypanosoma brucei rhodesiense. The dichloromethane extract displayed strong antiplasmodial and antitrypanosomal activities with IC50 values of 8.10 and 1.10 µg/mL against K1 strain of the malaria parasite and STlB900 strain of T. b. rhodesiense, respectively. Among the compounds evaluated for inhibition of trypomastigotes, both drimane and coloratane sesquiterpenes possessing aldehyde groups at positions 8 and 9 were found to show most antitrypanosomal activity with IC50 values in the range 0.56–6.4 µM. The antiplasmodial assays also revealed that the six coloratane and six drimane sesquiterpenes isolated from this extract exhibited significant antitrypanosomal activity with IC50 values ranged from 0.45 to ?114 µM. Among the compounds tested against the malarial parasite P. falciparum 11?‐hydroxymuzigadiolide (3) was most active with an IC50 value of 6.40 µM. Copyright © 2010 John Wiley & Sons, Ltd.
The hydrogen atom in a semi‐infinite space with an elliptical cone boundary
Authors: Méndez‐Fragoso R. , Ley‐Koo E. 
Published: May 2010

AbstractThe Schrödinger equation for the Hydrogen atom in spheroconal coordinates admits factorizable solutions, due to the fact that the Hamiltonian, the square of the angular momentum, and a linear combination of the squares of the Cartesian components of the angular momentum form a complete set of commuting operators. The linear combination defines the geometry of a family of elliptical cones, each one of which may serve as a confining boundary for the Hydrogen atom allowing the construction of its exact eigenfunctions expressed as the products of radial Laguerre polynomial functions and quasi‐periodic Lamé spheroconal harmonic functions in the elliptical cone coordinates. The boundary condition, requiring the vanishing of the wave function at the confining elliptical cone, introduces noninteger values of the angular momentum quantum label, as well as the breaking of the parity symmetry. Numerical results of the energy spectra, electric dipole moment, and pressure distribution of the Hydrogen atom are reported for different shapes and positions of the confining boundary. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical study on the reactions of Nb and Nb+ with CO2 in gas phase
Authors: Han De‐Man , Dai Guo‐Liang , Chen Hao , Wang Yong , Zhong Ai‐Guo , Lin Cai‐Ping , Chen Dan 
Published: May 2010

AbstractDensity functional theory calculations have been performed to explore the potential energy surfaces of CO bond activation in CO2 molecule by gas‐phase Nb atom and Nb+ cation for better understanding the reaction mechanism of second‐row metal with CO2. The minimum‐energy reaction path is found to involve the spin inversion in the different reaction steps. This potential energy curve‐crossing dramatically affects the reaction energetic. The present results show that the mechanism is insertion‐elimination mechanism along the CO bond activation reaction. All theoretical results not only support the existing conclusions inferred from early experiment but also complement the pathway and mechanism for this reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Calculating electron binding energies for quadratic fermion Hamiltonian by virtue of the IEO method
Authors: Fan Hong‐Yi , Yuan Hong‐Chun , Chen Jun‐hua 
Published: May 2010

AbstractIn this work, we discuss how to use the invariant eigen‐operator (IEO) method to derive the electron binding energies for the quadratic fermion Hamiltonian. We find that the task of solving the energy gap of fermion Hamiltonian can be ascribed to simply solving a standard eigenvalue problem of a numerical matrix, which is determined by the parameters of the given Hamiltonian. The IEO method provides us with a new approach for solving quadratic Hamiltonians in a more convenient and concise way. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Hydrogen bond cooperativity in dimers of hydroxamic acids
Authors: Kaur Damanjit , Kohli Ruchi 
Published: May 2010

AbstractMolecular orbital calculations are performed on various dimeric forms of four tautomers each of thioformohydroxamic acid and formohydroxamic acid. The analysis of stabilization energies associated with the dimerization and their correlation to proton affinities and deprotonation enthalpies of different potential sites present in the molecules indicate that the highest stabilization results when the most basic, site of the molecule acts as hydrogen bond acceptor but combination of the most acidic and the most basic site does not result in the largest stabilization when dimerization occurs. The presence of hydrogen bond cooperativity is indicated and the reasons for the observed cooperativity are explored in this study. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
On Randić indices of trees, unicyclic graphs, and bicyclic graphs
Authors: Du Zhibin , Zhou Bo 
Published: May 2010

AbstractThe Randić (connectivity) index is one of the most successful molecular descriptors in structure‐property and structure‐activity relationships studies. We determine the n‐vertex trees with the third for n ≥ 7, the fourth for n ≥ 10, the fifth and the sixth for n ≥ 11 maximum Randić indices, unicyclic graphs with the third for n ≥ 5, the fourth for n ≥ 7, and the fifth for n ≥ 8 maximum Randić indices, and bicyclic graphs with the second and the third for n ≥ 7, the fourth and the fifth for n ≥ 9 maximum Randić indices. We also determine the n‐vertex tree(s) for n ≥ 6 with the fifth minimum Randić index, unicyclic graphs for n ≥ 5 with the second, the third and the fourth minimum Randić indices, and bicyclic graph(s) for n ≥ 5 with the second minimum Randić index. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical investigation of molecular interactions in dioxane and water using hydrogen bonding model and density functional method
Authors: Chaudhari Ajay , Naganathappa Mahadevappa , Shinde M.N. , Kumbharkhane A. C. 
Published: May 2010

AbstractThe molecular interactions between water and dioxane are studied using hydrogen bonding model and density functional method. The average number of hydrogen bonds obtained using hydrogen bonding model is maximum at 0.83 mole fraction of water in dioxane. This concentration corresponds to five water molecules and a dioxane molecule in a complex [Mashimo et al., J Chem Phys 1992, 96, 6358; Kanse et al., J Ind Chem Soc 2007, 83, 168]. The values of dielectric constant for the mixture obtained by hydrogen bonding model are in excellent agreement with the experimental values. Density functional theory calculations show that the most stable conformer of dioxane–5H2O hydrogen bonded complex has six short hydrogen bonds. Number of hydrogen bonds from density functional calculations and hydrogen bonding model are in excellent agreement at 0.83 mole fraction of water. In this hydrogen bonded complex five water molecules bridging the two oxygen atoms of dioxane molecule and thus is a cyclic structure, which is also in agreement with the experiment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Substituent and solvent effects on the structural bioactivity and anticancer characteristic of catechin as a bioactive constituent of green tea
Authors: Monajjemi M. , Khosravi M. , Honarparvar B. , Mollaamin F. 
Published: May 2010

AbstractIn this study, quantum chemical calculations using density functional theory and 6‐311G (d) basis set have been applied to analyze the substituent effect on the electronic structural properties including thermochemical parameters as well as anticancer characteristics of catechin as a bioactive constituent of green tea. It has been found out that different substituents with two kinds of electron donating and electron withdrawing groups including NO2, NH2, Cl, OCH3, and CH3leaded to different structural stabilities. The catechin with chloro substituents has been referred to the most stable catechin derivatives based on the minimum energy of investigated compounds. In this study, the calculated values have been compared in gas phase and different solvent media with a wide range of solvent dielectrics using the self‐consistent reaction field method with polarizable continuum model. Relative interaction energies between solute and solvent as well as dipole moment values have been analyzed. The results of solvent effect study revealed that the formation of hydrogen bonds accounts for the stabilization of catechin. These calculated data were found to be a logical way in predicting the relative stability of catechin derivatives and can be useful for drug design of anticancer drugs and would open a new door for the researchers who are interested in natural products. The results presented in this article will be helpful to improve existing model and will open up a whole new arena of study to understand the anticancer characteristic of these antioxidant drugs derived from natural products against the photosensitizing DNA damage induce by catechin extracts and enable a much clearer understanding of how anticancer drugs mediate their effects on the specific spot. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Fluorescence and phosphorescence of acetone in neat liquid and aqueous solution studied by QM/MM and PCM approaches
Authors: Aidas Kęstutis , Mikkelsen Kurt V. , Mennucci Benedetta , Kongsted Jacob 
Published: May 2010

AbstractElectronic singlet and triplet nπ* absorption and emission energies of acetone in vacuum, neat liquid and aqueous solution have been calculated. Electronic states of acetone in solution have been modelled using combined molecular dynamics‐quantum mechanics/molecular mechanics techniques and the polarizable continuum model. In addition, we have compared density functional theory based results to corresponding coupled cluster singles and doubles predictions. Theoretical results have also been compared to experimental data. In general, we have obtained a good description of solvent effects on the absorption energies. However, modelling of excited states explicitly is still a challenge for the applied approaches, as the solvent shifts of the singlet nπ* emission have been considerably underestimated and also the solvent shift related to the Stokes shifts of fluorescence was predicted to have incorrect sign compared to available experimental data. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The localized electrons detector as an ab initio representation of molecular structures
Authors: Bohórquez Hugo J. , Matta Chérif F. , Boyd Russell J. 
Published: May 2010

AbstractThe local single particle momentum is proposed as a localized‐electrons detector (LED) that provides a direct three‐dimensional representation of bonding interactions in molecules. It is given exclusively in terms of the electron density and its gradient. We show that the graphical representation of bonding interactions given by LED is consistent with the local curvatures of the electron density as given by the eigenvalues of the Hessian matrix, according to a local symmetry classification of the critical points here introduced. LED consistently complements the topological analysis of the electron density given by the quantum theory of atoms in molecules, by providing a graphical representation of the symmetry of the bonding interactions in molecular systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2418–2425, 2010
Physical constraints on the distribution of macrophytes linked with flow and sediment dynamics in British rivers
Authors: O'Hare J. M. , O'Hare M. T. , Gurnell A. M. , Dunbar M. J. , Scarlett P. M. , Laizé C. 
Published: May 2010

AbstractAquatic vegetation plays a role in engineering river channels by altering patterns of flow velocity, sediment dynamics and, consequently, development and turnover of habitats. This could potentially aid in the rehabilitation of over‐widened, straightened channels, and, less desirably, reduce channel conveyance and contribute to flooding problems. Therefore, it is important to understand the environmental conditions in which in‐stream and marginal vegetation can reach sufficient abundance for these engineering roles to have a significant impact on the physical environment.Macrophyte and environmental data from 1653 river reaches across Great Britain were collated. Specific stream power (SSP) was calculated to represent hydrological disturbance and a median bed calibre index and percentage sand and finer sediment were used to characterize substrate size, since stream energy and sediment properties are two major physical controls on aquatic vegetation. Correlation and Principal Component Analysis (PCA) revealed subtly different physical habitat ‘preferences’ between species of contrasting morphology. Correlations of additional environmental data with SSP indicated that this physical disturbance variable also reflects gradients in stress variables describing nutrient availability and latitude and so is a useful integrator of a number of important pressures on plant survival.A conceptual model was produced which indicates ranges of SSP which may determine the significance of aquatic macrophytes in channel engineering processes. This model could contribute to predicting the potential for macrophyte growth within a given reach thus indicating its capacity for self‐restoration or the likelihood of weed problems. Copyright © 2010 John Wiley & Sons, Ltd.
Value creation, competition, and performance in buyer‐supplier relationships
Authors: Chatain Olivier 
Published: May 2010

AbstractThe value‐based approach to strategy argues that a firm's ability to capture value depends on the extent of its added value. In this paper, I empirically test the link between added value and value capture using a longitudinal dataset of United Kingdom law firm performance, capabilities, and client relationships. In this setting, competitors relevant for defining a firm's added value are those that share a client with the firm. Further, within a client relationship, value creation, and hence added value, can be decomposed in two parts: product‐line capability and client‐specific scope economies. I find that added value, measured at the level of each buyer‐supplier relationship, is a driver of relationship stability and supplier profitability. This suggests that suppliers with similar capabilities might enjoy different economic returns depending on the composition of their set of relevant competitors. These findings shed light on the conditions under which firms can appropriate returns from their capabilities. They indicate that concepts from cooperative games can be fruitfully applied to empirical studies of firm performance and to the elaboration of insights from the resource‐based view of the firm. Copyright © 2010 John Wiley & Sons, Ltd.
Breakup of Gas Bubbles Rising in Molten Metals
Authors: Wichterle K. 
Published: May 2010

AbstractA theory on the breakup of rising bubbles is developed on the basis of long‐term experiments with bubbles rising in different liquids. The probability of bubble breakup is expressed in terms of half‐life as a dimensionless function of the bubble volume and liquid properties. The results are applied to develop a mathematical model of bubbles rising in a column of high density liquid under a low external pressure. The model predicts that in typical steelmaking equipment the size of bubbles approaching the liquid level depends mostly on the external pressure and it is quite independent of the original size of the bubbles.
Interaction Parameter e for Carbon‐saturated Liquid Iron between 1623 and 1723 K
Authors: Kashiwaya Y. , Hasegawa M. , Niitani H. , Kakinuma T. , Iwase M. 
Published: May 2010

AbstractIn order to derive the values of the interaction parameter, $e_O^C$, in carbon‐saturated {Fe‐C} liquid alloys, as defined below;

an electrochemical technique incorporating zirconia solid electrolyte was applied for the direct measurements of the Henrian activities of oxygen, hO, between 1623 and 1723 K, while the concentrations of oxygen and carbon in pct by weight, [%O] and [%C]Sat, respectively, were determined by using a conventional LECO analyzer. The results can be summarized as
A Comparison of a Two‐Dimensional and a Three‐Dimensional Method for Inclusion Determinations in Tool Steel
Authors: Doostmohammadi H. , Karasev A. , Jönsson P.G. 
Published: May 2010

AbstractTo produce clean commercial tool steel the non‐metallic inclusions characteristics have to be known, since they influence the mechanical properties of steel. In this work, inclusion characteristics in steel samples from plant trials were studied. The samples were collected in the steel plant according the two following methods: (a) 2D investigations of inclusions by a cross sectional method and (b) 3D investigations of inclusions collected on a film filter after electrolytic extraction. More specifically, the chemical composition, morphology, number and size distribution of inclusions in tool steel samples taken from ladle during melt treatment were determined by both methods. In both methods SEM equipped with EDS was used for compositional analysis of inclusions. In addition, in the cross sectional method an automated detection program called ‘INCAFeature’ was used to collect more statistics of non‐metallic inclusions. The composition of inclusions larger than 5 µm was found to contain 49% CaO based on the results from both methods. However, for smaller inclusions it was found that the accuracy of the 2D method was less than that of the 3D method due to the influence of the metal matrix on the results. In addition, it was found that a critical inclusion size of 4 µm could be defined for the 3D method, above which the standard deviation in composition determination was very low.
On Phase Equilibria in Duplex Stainless Steels
Authors: Wessman S. , Pettersson R. , Hertzman S. 
Published: May 2010

AbstractThe equilibrium conditions of four duplex stainless steels; Fe‐23Cr‐4.5Ni‐0.1N, Fe‐22Cr‐5.5Ni‐3Mo‐0.17N, Fe‐25Cr‐7Ni‐4Mo‐0.27N and Fe‐25Cr‐7Ni‐4Mo‐1W‐1.5Cu‐0.27N were studied in the temperature region from 700 to 1000 °C. Phase compositions were determined with SEM EDS and the phase fractions using image analysis on backscattered SEM images. The results showed that below 1000 °C the steels develop an inverse duplex structure with austenite and sigma phase, of which the former is the matrix phase. With decreasing temperature, the microstructure will be more and more complex and finely dispersed. The ferrite is, for the higher alloyed steels, only stable above 1000 °C and at lower temperatures disappears in favour of intermetallic phases. The major intermetallic phase is sigma phase with small amounts of chi phase, the latter primarily in high Mo and W grades. Nitrides, not a focus in this investigation, were present as rounded particles and acicular precipitates at lower temperatures. The results were compared to theoretical predictions using the TCFE5 and TCFE6 databases.