bluuebunny/crossref_metadata_2025 huggingface dataset:
Coda
Authors: Purslow Vicki T. , Cook Florence Christine
Published: May 2010

Technology and globalization have the potential to make higher education more affordable and accessible. In practice, however, rising costs limit educational access, and competition threatens the sustainability of many colleges and universities (Grummon, 2009). With the relevance of traditional curricula in question and the demand for alternate delivery methods expanding, many higher learning institutions face a challenge to reinvent themselves (Barnatt, 2008; Grummon, 2009; Lee, Brennan, & Green, 2009).

We asked four higher education leaders from demographically and structurally diverse institutions to address the question, “How will colleges and universities serve the global knowledge economy in the coming decades?” Our respondents represent perspectives from multiple educational paradigms—public and private, local and international, for‐profit and nonprofit, brick‐and‐mortar and online.

George Mihel, president of Sauk Valley Community College in Illinois, offers a position paper on the need to transform some of higher education’s deep‐rooted institutional traditions. George Miller, chancellor of American InterContinental University, teams with Caroline Molina‐Ray, a University of Phoenix faculty member, to address how higher education can foster both technological competency and critically reflexive thinking. Naana J. S. Opoku‐Agyemang, vice chancellor of the University of Cape Coast in Ghana, offers insight into the unique challenges and accomplishments of higher education in Africa. Finally, Vicki T. Purslow, associate dean of the College of Arts and Sciences at Southern Oregon University, and Christine Cook Florence, a higher education marketing consultant, present a commentary synthesizing the symposium contributions and issuing a call to action for higher education leaders. Together, these diverse perspectives offer a glimpse into the higher education of the future.</
Portal vein thrombosis and liver transplant survival benefit
Authors: Englesbe Michael J. , Schaubel Douglas E. , Cai Shijie , Guidinger Mary K. , Merion Robert M.
Published: May 2010

Portal vein thrombosis (PVT) complicates the liver transplant operation and potentially affects waiting list survival. The implications on calculations of survival benefit, which balance both waiting list and posttransplant survival effects of PVT, have not been determined. The objective of this study is to describe the effect of PVT on the survival benefit of liver transplantation. Using Scientific Registry of Transplant Recipients data on adult liver transplant candidates wait-listed between September 2001 and December 2007, Cox proportional hazard models were fitted to estimate the covariate-adjusted effect of PVT on transplant rate, waiting list survival, and posttransplant survival. We then used sequential stratification to estimate liver transplant survival benefit by cross-classifications defined by Model for End-Stage Liver Disease (MELD) score and PVT status. The prevalence of reported PVT among 22,291 liver transplant recipients was 4.02% (N = 897). PVT was not a predictor of waiting list mortality (hazard ratio = 0.90, P = 0.23) but was a predictor of posttransplant mortality (hazard ratio = 1.32, P = 0.02). Overall, transplant benefit was not significantly different for patients with PVT versus without PVT (P = 0.21), but there was a shift in the benefit curve. Specifically, the threshold for transplant benefit among patients without PVT was MELD score >11 compared to MELD score >13 for patients with PVT. PVT is associated with significantly higher posttransplant mortality but does not affect waiting list mortality. Among patients with low MELD score, PVT is associated with less transplant survival benefit. Clinicians should carefully consider the risks of liver transplantation in clinically stable patients who have PVT. Liver Transpl 16:999-1005, 2010. © 2010 AASLD.
Supramolecular Assembly of Designed α‐Helical Polypeptide‐Based Nanostructures and Luminescent Conjugated Polyelectrolytes
Authors: Wigenius Jens , Björk Per , Hamedi Mahiar , Aili Daniel
Published: May 2010

Designed polypeptides with controllable folding properties are utilized as supramolecular templates for fabrication of ordered nanoscale molecular and fibrous assemblies of LCPs. The properties of the LCPs as well as the three dimensional conformation of the polypeptide‐scaffold determine how the polymers are arranged in the supramolecular construct, which highly affects the properties of the hybrid material. The ability to control the polypeptide conformation and assembly into fibers provides a promising route for tuning the optical properties of LCPs and for fabrication of complex functional supramolecules with well defined structural properties.

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Characterization of Reversible Associations by Sedimentation Velocity with UltraScan
Authors: Demeler Borries , Brookes Emre , Wang Renjing , Schirf Virgil , Kim Chongwoo A.
Published: May 2010

We compare here the utility of sedimentation velocity (SV) to sedimentation equilibrium (SE) analysis for the characterization of reversible systems. Genetic algorithm optimization in UltraScan is used to optimize the model and to obtain solution properties of all components present in the system. We apply our method to synthetic and experimental data, and suggest limits for the accessible kinetic range. We conclude that equilibrium constants obtained from SV and SE analysis are equivalent, but that SV experiments provide better confidence for the Kd, can better account for the presence of contaminants and provide additional information including rate constants and shape parameters.

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Spectral theory and iterative methods for the Maxwell system in nonsmooth domains
Authors: Mitrea Irina , Ott Katharine
Published: May 2010

We study spectral properties of boundary integral operators which naturally arise in the study of the Maxwell system of equations in a Lipschitz domain Ω ⊆ ℝ3. By employing Rellich‐type identities we show that the spectrum of the magnetic dipole boundary integral operator (composed with an appropriate projection) acting on L2(∂Ω) lies in the exterior of a hyperbola whose shape depends only on the Lipschitz constant of Ω. These spectral theory results are then used to construct generalized Neumann series solutions for boundary value problems associated with the Maxwell system and to study their rates of convergence (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orientation and Dynamics of ZnO Nanorod Liquid Crystals in Electric Fields
Authors: Zorn Matthias , Tahir Muhammad Nawaz , Bergmann Björn , Tremel Wolfgang , Grigoriadis Chris , Floudas George , Zentel Rudolf
Published: May 2010

ZnO nanorod polymer hybrids (i.e., ZnO nanorods coated with a block copolymer with a short anchor block (dopamine) and a longer solubilizing block of polystyrene (PS)) form liquid crystalline (LC) phases if they are dispersed at high concentration e.g., in a PS oligomer matrix. Due to the high mobility of the low Tg‐matrix the nanorod polymer hybrids show a switching behavior under an applied AC electric field. Hence, the orientation of the nanorod mesogens can be changed from planar (parallel to the substrate) to homeotropic (perpendicular) in full analogy to the switching of low molecular liquid crystals in an electric field. Dielectric measurements show that such a switching is mainly due to the cooperative LC behavior, because the rods themselves exhibit only a very small effective dipole moment. The process can be investigated by polarizing microscopy. SEM images show the orientations of the individual nanorods, which correspond to the Fredericks transition well known for liquid crystals aligned in an electric field. This was the first time such a transition could be visualized by electron microscopy due to the large nanorod mesogens. The observation is interesting to orient nanorods perpendicular to an electrode and can help to improve optoelectronic devices.

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Conformational Properties of Polymer Mushrooms Under Spherical and Cylindrical Confinement
Authors: Wang Rong , Virnau Peter , Binder Kurt
Published: May 2010

A coarse grained model of a flexible macromolecule end‐grafted on the inside of a sphere or a cylinder under good solvent conditions is studied by Monte Carlo simulations. For cylindrical confinement, two regimes are found: when the cylinder radiusRexceeds the gyration radiusRgoof the polymer mushroom grafted to a planar surface, a simple scaling description holds. In the opposite case, a non‐monotonic crossover to a cigar‐like quasi‐one‐dimensional structure occurs, and the distributionPe(x) of the free chain end in thex‐direction along the cylinder axis becomes bimodal. Spherical confinement, on the other hand, causes a crossover from dilute to semidilute behavior of the structural properties.

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Fingertip replantation at or beyond the nail base in children
Authors: Shi Dehai , Qi Jian , Li Donghui , Zhu Lei , Jin Wentao , Cai Daozhang
Published: May 2010

Although success of digital replantations in children has been reported by many authors, the very distal fingertip replantation remains technically demanding. The aim of this article is to review our experience with fingertip replantations at or distal to the nail base in pediatric patients and evaluate the clinical outcomes. From October 2000 to May 2007, 12 pediatric fingertips amputated at or distal to the nail base were replanted. Only one artery was anastomosed for revascularization with or without nerve repair; vein drainage was provided by the controlled bleeding technique. Eleven of the 12 replants (91%) survived; one replant of crushed digit failed. An average of 26 month (range, 6 to 36 months) follow‐up revealed excellent restoration of finger motion and appearance. The regained static 2‐point discrimination (S2PD) sensation was from 3.2 to 5.0 mm (mean, 4.2 mm). Both the parents and the children were satisfied with the final results. In conclusion, fingertip replantation in children allows good functional and esthetical recovery and should be attempted if technically feasible. © 2010 Wiley‐Liss, Inc. Microsurgery 30:380–385, 2010.
Synchronous behaviors of CBP and acetylations of lysine 18 and lysine 23 on histone H3 during porcine oocyte first meiotic division
Authors: Xue Kai , Song Jiazhe , Wei Hengxi , Chen Li , Ma Yufang , Liu Shen , Li Yan , Dai Yunping , Zhao Yaofeng , Li Ning
Published: May 2010

As a transcriptional coactivator and acetyltransferase, CREB‐binding protein (CBP) is widely characterized due to its functions in cell proliferation and development. However, the activities of CBP in oocyte meiosis are not completely clear. Here we showed that the localization and expression of CBP changed regularly with the progression of porcine oocyte meiosis. The emergence of CBP in chromosomal domains is temporally coincident with the establishments of acetylated lysine 18 (AcH3/K18), lysine 23 (AcH3/K23) and dimethylated arginine 17 (dime‐H3/R17) of histone H3 at meiotic stages from germinal vesicle breakdown (GVBD) to metaphase I (MI). Both CBP expression and these three histone modifications persisted to telophase I (TI). When trichostatin A (TSA) was used to enhance histone acetylations in porcine oocytes, we found that hyperacetylations of H3K18 and H3K23 occurred at meiotic stage from GVBD to TI, together with advanced and enhanced expression of CBP in the nucleus. In addition, disturbance of CBP activity by treatment with 2‐Naphthol‐AS‐Ephosphate (KG‐501, a drug targeting the KIX domain of CBP that disrupts the formation of CBP functional complex) led to synchronous decreases of CBP expression, AcH3/K18 and AcH3/K23 in chromosomal domains during oocyte meiosis. Therefore, these results indicate that the synchronous changes of CBP expression, AcH3/K18 and AcH3/K23 occur during porcine oocyte meiosis. Mol. Reprod. Dev. 77: 605–614, 2010. © 2010 Wiley‐Liss, Inc.
Body weight, social competence, and cognitive functioning in survivors of childhood brain tumors
Authors: Schulte Fiona , Bartels Ute , Bouffet Eric , Janzen Laura , Hamilton Jill , Barrera Maru
Published: May 2010

Background

The purpose of the following article was to examine: (a) body mass index (BMI) in survivors of childhood brain tumors; (b) the association of BMI with social competence and cognitive functioning; and (c) congruency in reporting of survivors' social competence by the survivors, parents, and teachers.

Procedure

Fifty‐four survivors of childhood brain tumors (32 males) 8–18 years participated. BMI‐for‐age percentiles and BMI Z‐scores (SDS) were calculated and survivors were categorized as underweight, normal, overweight, or obese, using established criteria. Informants completed measures of social competence and internalizing behaviors. Survivors also completed a test of self‐perception and cognitive functioning (IQ).

Results

Survivors were more underweight (15% vs. 4%), and less overweight (17% vs. 31%) than population norms (χ2 = 38.62, P < 0.001). Parents perceived lower social competence in survivors that were underweight, had lower verbal IQ, and higher internalizing behaviors (P < 0.05). A significant interaction between BMI‐for‐age and IQ on self‐perception of close friendships suggested that survivors with lower weight and lower IQ perceived having fewer close friendships (P < 0.05). Congruency among the three informants was moderate.

Conclusions

Survivors of childhood brain tumors are at increased risk for underweight. Underweight status is related to lower parent reported social competence and survivors' self‐perception of fewer close friendships in the presence of low IQ. Pediatr Blood Cancer. 2010;55:532–539. © 2010 Wiley‐Liss, Inc.
Co‐ and post‐translational modifications of the 26S proteasome in yeast
Authors: Kikuchi Julia , Iwafune Yuko , Akiyama Tomoko , Okayama Akiko , Nakamura Hiroki , Arakawa Noriaki , Kimura Yayoi , Hirano Hisashi
Published: May 2010

The yeast (Saccharomyces cerevisiae) 26S proteasome consists of the 19S regulatory particle (19S RP) and 20S proteasome subunits. We detected comprehensively co‐ and post‐translational modifications of these subunits using proteomic techniques. First, using MS/MS, we investigated the N‐terminal modifications of three 19S RP subunits, Rpt1, Rpn13, and Rpn15, which had been unclear, and found that the N‐terminus of Rpt1 is not modified, whereas that of Rpn13 and Rpn15 is acetylated. Second, we identified a total of 33 Ser/Thr phosphorylation sites in 15 subunits of the proteasome. The data obtained by us and other groups reveal that the 26S proteasome contains at least 88 phospho‐amino acids including 63 pSer, 23 pThr, and 2 pTyr residues. Dephosphorylation treatment of the 19S RP with λ phosphatase resulted in a 30% decrease in ATPase activity, demonstrating that phosphorylation is involved in the regulation of ATPase activity in the proteasome. Third, we tried to detect glycosylated subunits of the 26S proteasome. However, we identified neither N‐ and O‐linked oligosaccharides nor O‐linked β‐N‐acetylglucosamine in the 19S RP and 20S proteasome subunits. To date, a total of 110 co‐ and post‐translational modifications, including Nα‐acetylation, Nα‐myristoylation, and phosphorylation, in the yeast 26S proteasome have been identified.
Protein interactions with the platelet integrin αIIb regulatory motif
Authors: Raab Markus , Daxecker Heide , Edwards Richard J. , Treumann Achim , Murphy Derek , Moran Niamh
Published: May 2010

Integrins are transmembrane proteins regulating cellular shape, mobility and the cell cycle. A highly conserved signature motif in the cytoplasmic tail of the integrin α‐subunit, KXGFFKR, plays a critical role in regulating integrin function. To date, six proteins have been identified that target this motif of the platelet‐specific integrin αIIbβ3. We employ peptide‐affinity chromatography followed‐up with LC‐MS/MS analysis as well as protein chips to identify new potential regulators of integrin function in platelets and put them into their biological context using information from protein:protein interaction (PPI) databases. Totally, 44 platelet proteins bind with high affinity to an immobilized LAMWKVGFFKR‐peptide. Of these, seven have been reported in the PPI literature as interactors with integrin α‐subunits. 68 recombinant human proteins expressed on the protein chip specifically bind with high affinity to biotin‐tagged α‐integrin cytoplasmic peptides. Two of these proteins are also identified in the peptide‐affinity experiments, one is also found in the PPI databases and a further one is present in the data to all three approaches. Finally, novel short linear interaction motifs are common to a number of proteins identified.
Top‐down analysis of recombinant histone H3 and its methylated analogs by ESI/FT‐ICR mass spectrometry
Authors: Han Jun , Borchers Christoph H.
Published: May 2010

Detailed characterization of the amino acid (aa) compositions of recombinant histone H3 (Xenopus laevis) and its Lys‐9 mono‐, di‐, and trimethylated isoforms was carried out by ESI/FT‐ICR‐MS. The measured molecular masses of these four proteins did not agree with those predicted from the published wild‐type histone H3 sequence. Using MS/MS with both collision‐activated dissociation and electron capture dissociation, three aa substitutions (Gly102Ala, Cys110Ala, and Gly111Ala) were unambiguously identified in each protein by protein database searching and de novo peptide tag sequencing. In addition, it was determined through accurate mass measurement and elemental composition generation that Lys‐9, to which the methyl groups are attached, is not in fact a lysine. Instead, it was identified as a chemical analog of lysine – aminoethylcysteine – in the methylated proteins. After incorporation of these three aa substitutions and the aminoethylcysteine into the protein sequences, the re‐calculated molecular masses of four proteins were completely consistent with the measured values within 1 ppm. This work demonstrates the power of top‐down MS for a detailed structural confirmation of recombinant proteins, even without prior information on aa substitutions or modifications.
Fatigue in stroke rehabilitation patients: a pilot study
Authors: Chestnut Thomas John
Published: May 2010

Background 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

The 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

The 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

The 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

Density 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

In 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

Molecular 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

The 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

The 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

In 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

Electronic 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

The 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

Aquatic 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

The 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

A 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

In 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

To 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

The 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.
Effects of Magnetic Field Direction on γ‐fiber Texture Evolution in Cold‐rolled Interstitial‐free Steel Sheet during Annealing
Authors: Wu Y. , He C.S. , Zhao X. , Zuo L.
Published: May 2010

The effects of magnetic field direction on γ‐fiber texture evolution in as‐annealed interstitial‐free (IF) steel sheet were investigated by means of X‐ray diffraction ODF analysis. Specimens cut from cold‐rolled IF steel sheets were placed at the center of a 12‐T magnetic field, tilted by different angles to the magnetic field direction respectively, and annealed at 750 °C for 30 min. The results show that altering the specimen orientation to the magnetic field direction during annealing does not change the final annealing textures. The average intensity of the γ‐fiber texture of specimens annealed under the magnetic field is higher compared to conventionally annealed specimens. The intensity of the main γ‐fiber texture components presents a similar periodic variation with respect to the specimen orientation to the magnetic field, i.e., it is weakened as the tilt angle increases from 0°, and subsequently strengthened to a maximum value at 45°, and then weakened again as the tilt angle continues to increase. When the magnetic field is applied in the direction perpendicular to the specimen's rolling plane, the intensity of the main γ‐fiber texture components of specimens annealed in the magnetic field is close to that of the specimen annealed without field. This phenomenon might be attributed to the demagnetic effect.
Globular Structure of M2 High Speed Steel by Thermomechanical Treatment in the Semisolid State
Authors: Amin‐Ahmadi B. , Aashuri H.
Published: May 2010

The globular structure of M2 high speed steel in the rolled ‐ annealed and as cast conditions was investigated in the semisolid state. Metallographic observations resulted in globular austenite particles that were surrounded by a liquid phase. Dissolution of various carbides in the austenite phase at semisolid temperatures led to grain boundary liquation and formation of near‐spherical solid grains in a liquid matrix. Therefore, at the semisolid state, the solid particles were free from carbides. MC‐ type and M6C‐ type eutectic carbides re‐ precipitated at the grain boundaries during cooling of the samples from the semisolid temperature. The variation of shape factor versus holding time and holding temperature was examined. A transition value for shape factor changes in high speed steels was achieved. The growth rate constants of the Ostwald ripening and the coalescence mechanisms were calculated by using the experimentally determined rate constant. It was observed that less liquid droplets were enclosed inside the solid particles compared with non‐ferrous alloys. Besides, it has been shown that at high solid fraction, the Ostwald ripening mechanism plays a prominent role in the coarsening phenomenon in comparison with the coalescence mechanism. Grains can rotate and arrange low misorientation with each other at high liquid contents, therefore low energetic grain boundaries form between these grains. These grain boundaries play an important role in the coalescence mechanism.
Integration of Blood Outgrowth Endothelial Cells in Dermal Fibroblast Sheets Promotes Full Thickness Wound Healing
Authors: Hendrickx Benoit , Verdonck Kristoff , Van den Berge Stefaan , Dickens Stijn , Eriksson Elof , Vranckx Jan Jeroen , Luttun Aernout
Published: May 2010

Vascularization is the cornerstone of wound healing. We introduced human blood outgrowth endothelial cells (hBOEC) in a self-assembled human dermal fibroblast sheet (hDFS), intended as a tissue-engineered dermal substitute with inherent vascular potential. hBOEC were functionally and molecularly different from early endothelial progenitor cells and human umbilical vein endothelial cells (HUVEC). hBOEC alone, unlike HUVEC, efficiently revascularized and re-oxygenated the wound bed, both by active incorporation into new vessels and by trophic stimulation of host angiogenesis in a dose-dependent manner. Furthermore, hBOEC alone, but not HUVEC, accelerated epithelial coverage and matrix organization of the wound bed. In addition, integration of hBOEC in hDFS not only further improved vascularization, epithelial coverage and matrix organization but also prevented excessive wound contraction. In vitro analyses with hBOEC, fibroblasts and keratinocytes revealed that these effects were both due to growth factor crosstalk and to short cutting hypoxia. Among multiple growth factors secreted by hBOEC, placental growth factor mediated at least in part the beneficial effects on keratinocyte migration and proliferation. Overall, this combined tissue engineering approach paves the way for clinical development of a fully autologous vascularized dermal substitute for patients with large skin defects that do not heal properly.
Induction of micronuclei on Greek hairdressers occupationally exposed to chemical mixtures
Authors: Vlastos Dimitris , Ntinopoulos Alexandros
Published: May 2010

Since the early 20th century, hairdressers (HD) have been exposed to a wide range of harmful chemical products. To determine the possible genetic damage to HD, as a result of their occupational exposure to combinations of different chemical factors, we applied the micronucleus assay on their peripheral blood lymphocytes cultures. The micronucleus assay was performed on blood samples from 20 Greek female HD and 20 control women, having no connection with the occupation, from the same area. In the results analysis, parameters included were age, smoking habits, and duration of occupational exposure. The results of our study showed a significant increase in HD micronuclei (MN) frequency, compared to the controls (13.4 ± 1.00 vs. 8.05 ± 0.65). The frequency of large‐size MN was significantly higher in the HD and presented potential correlation with the phenomenon of aneuploidy. A statistically significant difference in the frequency of MN between HD and controls who smoked was observed, while this was not the case with the non smoker groups. However, multiple regression analysis showed no significant correlation between smoking habits and MN frequency. The observed increase of the frequency of MN in HD is attributed to the long‐term occupational exposure of HD in combination with different chemical factors. Since in the literature there are very few similar studies, further combined studies are suggested on a larger number of HD from different countries, combining biological and molecular techniques, as well as chemical analytical methods of determining and tracing the chemical factors in both the occupational environment and their organisms. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.