bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution of a conjecture of Tewes and Volkmann regarding extendable cycles in in‐tournaments
Authors: Meierling Dirk 
Published: April 2009

AbstractA directed cycle C of a digraph D is extendable if there exists a directed cycle C′ in D that contains all vertices of C and an additional one. In 1989, Hendry defined a digraph D to be cycle extendable if it contains a directed cycle and every non‐Hamiltonian directed cycle of D is extendable. Furthermore, D is fully cycle extendable if it is cycle extendable and every vertex of D belongs to a directed cycle of length three. In 2001, Tewes and Volkmann extended these definitions in considering only directed cycles whose length exceed a certain bound 3≤k<n: a digraph D is k ‐extendable if every directed cycle of length t, where k≤t<n, is extendable. Moreover, D is called fully k ‐extendable if D is k ‐extendable and every vertex of D belongs to a directed cycle of length k. An in‐tournament is an oriented graph such that the in‐neighborhood of every vertex induces a tournament. This class of digraphs which generalizes the class of tournaments was introduced by Bang‐Jensen, Huang and Prisner in 1993. Tewes and Volkmann showed that every connected in‐tournament D of order n with minimum degree δ≥1 is ($n- \lfloor {{4\delta+1} \over {3}} \rfloor$) ‐extendable. Furthermore, if D is a strongly connected in‐tournament of order n with minimum degree δ=2 or $\delta {>}{{8n-17}\over {31}}$, then D is fully ($n-\lfloor {{4\delta+1} \over {3}}\rfloor$) ‐extendable. In this article we shall see that if$3 \leq \delta \leq {{8n-17} \over {31}}$, every vertex of D belongs to a directed cycle of length $n-\lfloor {{4\delta+1} \over {3}}\rfloor$, which means that D is fully ($n-\lfloor {{4\delta+1} \over {3}}\rfloor$) ‐extendable. This confirms a conjecture of Tewes and Volkmann. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 82–92, 2010
Synthesis and bioactivity evaluation of 3‐hydroxy‐3‐(phenylethynyl)indol‐2‐one analogues
Authors: Chen Gang , Wang Ye , Gao Suo , He Hong‐Ping , Li Shun‐Lin , Zhang Jian‐Xin , Ding Jian , Hao Xiao‐Jiang 
Published: April 2009

Abstract
magnified imageA series of propargylic alcohol was synthesized by the addition of phenylacetylene to isatin and its N‐substituted derivatives for the first time. This reaction involves activation of zinc reagent via coordination with carbonyl substrates that behave “ligand like.” The bioactivities on protective effect on the apoptosis of PC12 cells induced by H2O2 and cytotoxicity against lung cancer A549 and P388 cell line of these compounds were investigated, and several compounds showed potent activities. J. Heterocyclic Chem., 46, 217 (2009).
A palladium catalyzed new synthesis of N,N‐dimethyl[1,8]‐naphthyridine‐2‐amines: Facile incorporation of N,N‐dimethylamino group from DMF in aqueous medium
Authors: Goswami Shyamaprosad , Das Nirmal Kumar 
Published: April 2009

Abstract
magnified imageHere we report Pd catalyzed synthesis of N,N‐dimethyl[1,8]naphthyridine‐2‐amines by facile incorporation of N(Me)2 group from DMF in moderate to good yield. J. Heterocyclic Chem., 46, 324 (2009).
Microwave‐assisted synthesis, metallation, and duff formylation of porphyrins
Authors: Yaseen Muhammad , Ali Mukhtar , NajeebUllah Muhammad , Ali Munawar Munawar , Khokhar Irshad 
Published: April 2009

Abstract
magnified imageMicrowave assisted synthesis, metallation, and β‐formylation of porphyrins is described. All synthetic reactions were carried out on inorganic polymer solid support using microwave energy. It is the first documented application of the Duff reaction in the field of porphyrins and metalloporphyrins. The overall process is simple, easy, and environment friendly. FTIR, UV–visible, elemental analysis, 1H NMR, and mass spectrometry were used to characterize the compounds. J. Heterocyclic Chem., 46, 251 (2009).
Gene expression during the oocyte‐to‐embryo transition in mammals
Authors: Evsikov Alexei V. , Marín de Evsikova Caralina 
Published: April 2009

AbstractThe seminal question in modern developmental biology is the origins of new life arising from the unification of sperm and egg. The roots of this question begin from 19th to 20th century embryologists studying fertilization and embryogenesis. Although the revolution of molecular biology has yielded significant insight into the complexity of this process, the overall orchestration of genes, molecules, and cells is still not fully formed. Early mammalian development, specifically the oocyte‐to‐embryo transition, is essentially under “maternal command” from factors deposited in the cytoplasm during oocyte growth, independent of de novo transcription from the nascent embryo. Many of the advances in understanding this developmental period occurred in tandem with application of new methods and techniques from molecular biology, from protein electrophoresis to sequencing and assemblies of whole genomes. From this bed of knowledge, it appears that precise control of mRNA translation is a key regulator coordinating the molecular and cellular events occurring during oocyte‐to‐embryo transition. Notably, oocyte transcriptomes share, yet retain some uniqueness, common genetic motifs among all chordates. The common genetic motifs typically define fundamental processes critical for cellular maintenance, whereas the unique genetic features may be a source of variation and a substrate for sexual selection, genetic drift, or gene flow. One purpose for this complex interplay among genes, proteins, and cells may allow for evolution to transform and act upon the underlying processes, at molecular, structural and organismal levels, to increase diversity, which is the ultimate goal of sexual reproduction. Mol. Reprod. Dev. 76: 805–818, 2009. © 2009 Wiley‐Liss, Inc.
Analytical solution to the transient phase of steady‐state free precession sequences
Authors: Ganter Carl 
Published: April 2009

AbstractThe transient phase of short–TR steady‐state free precession (SSFP) sequences exhibits an often striking complexity and is not only important for nonequilibrium applications (e.g., rapid T1–measurements), but can also cause severe artifacts in conventional imaging. In both cases, balanced SSFP sequences are practically (with regard to preparation efficiency) and conceptually (concerning the theoretical understanding of the decay) easier to handle their unbalanced counterparts, for which currently no theory is available. Based on a decomposition of coherence pathways into irreducible subpaths, an exact mathematical solution to the transient phase of unbalanced SSFP sequences is presented in this article, which also includes the known results for balanced SSFP and the steady state of arbitrary SSFP sequences as special cases. As an application, it is shown that the familiar Look–Locker expression for the accelerated magnetization recovery in RF‐spoiled sequences is only valid for T2 → 0. In addition to oscillatory perturbations, systematic deviations from the monoexponential decay are observed for T2 0 as a consequence of memory effects. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Consequence analysis to buildings from bursting cylindrical vessels
Authors: Ferradás Enrique González , Alonso Fernando Díaz , Pérez Juan Francisco Sánchez , Miñarro Marta Doval , Aznar Agustín Miñana , Gimeno José Ruiz 
Published: April 2009

AbstractDamage effects to buildings must be taken into account when performing consequence analysis, because people indoors can be affected by such damage. The objective of this article is to provide a methodology for estimating damage to buildings from the pressure wave produced by bursting cylindrical vessels, by combining characteristic overpressure‐impulse‐distance curves with PROBIT equations. This methodology allows the damage to be shown in the same diagram as the overpressure, impulse, and distance. Diagrams and equations are presented to determine minor damage to brick buildings of four or less floors (broken windows, displacement of doors and window frames, tile displacement, etc), major structural damage (cracks in walls, collapse of some walls), and collapse (the damage is so extensive that the building is partially or totally demolished). © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009
Atomic‐orbital‐symmetry based σ‐, π‐, and δ‐decomposition analysis of bond orders
Authors: Sizova Olga V. , Skripnikov Leonid V. , Sokolov Alexander Yu , Sizov Vladimir V. 
Published: April 2009

AbstractThe atomic‐orbital‐symmetry based (AOSB) scheme for the decomposition of Mayer and Wiberg bond orders into σ‐, π‐, and δ‐components is used to investigate different types of covalent bonds. Four series of compounds are studied: simple molecules with homonuclear bonds, inorganic molecules with polar heteronuclear bonds, [Ru(CN)5(XY)]q transition metal complexes with π‐acceptor ligands, and dimetal complexes with multiple metal–metal bonds. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Nephelauxetic effect revisited
Authors: Tchougréeff Andrei L. , Dronskowski Richard 
Published: April 2009

AbstractWe readdress the well‐known nephelauxetic effect in coordination compounds of transition metal ions and analyze its possible origins presented in the literature. The initial hypothesis was to ascribe the reduction of the effective Racah parameters B and C of the electron–electron interaction in the complexes as compared to their respective free ion values (which is the essence of the nephelauxetic effect) to the expansion of d‐orbitals in the complex because of their quantum mechanical mixing with the orbitals of the ligands leading to delocalization. This picture necessarily leads to a rigid positive correlation between the amount of the d‐shell splitting controlled by the same delocalization and the amount of the renormalization of the interaction parameters. In fact, such a rigid relation does not exist and the so‐called spectrochemical and nephelauxetic series of the ligands composed according to the aforementioned amounts do not coincide in many points. An alternative explanation based not on the delocalization, but on polarization of the ligands had been proposed at the same time as the delocalization based one. Realistic estimates had been obtained on this basis, but the scheme had never been implemented on the atomic scale, which is necessary to enable renormalization of the aforementioned interaction parameters as a “built‐in” function of quantum chemical software. The required atomic resolution formulation of the polarization‐based model of the nephelauxetic effect is constructed in this work, in which a relation of such an approach to the general problematics of the “next generation” of semiempirical methods of quantum chemistry is also discussed. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Theoretical mechanisms of the superoxide radical anion catalyzed by the copper‐zinc superoxide dismutase
Authors: Chen Dezhan , Wang Qingli , Zhang Honghong , Mi Shizhen , Wang Juliang , Zeng Qiang , Zhang Guiqiu 
Published: April 2009

AbstractThe disproportionation of superoxide radical anions catalyzed by copper‐zinc superoxide dismutase was investigated in detail using density functional theory. The structures of each stationary point and the transition states were located so that the reaction pathways were determined. The results indicate that the reactions proceed by two steps both for the oxidized process of superoxide radical anion and the reduced one. The rate for the determining step of the reaction (2) is in very good agreement with the experimental value. The solvation effect on the reaction was also discussed. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Quantitative assessment of the effect of basis set superposition error on the electron density of molecular complexes by means of quantum molecular similarity measures
Authors: Salvador Pedro , Fradera Xavier , Duran Miquel 
Published: April 2009

AbstractThe Chemical Hamiltonian Approach (CHA) method is applied to obtain Basis Set Superposition Error (BSSE)‐free molecular orbitals at the Hartree–Fock (HF) and Density Functional Theory (DFT) levels of theory. To assess qualitatively the effect of the BSSE on the first‐order electron density, we had previously applied Bader's analysis of the intermolecular critical points located on the electron density, as well as density difference maps for several hydrogen bonded complexes. In this work, Quantum Molecular Similarity Measures are probed as an alternative avenue to properly quantify the electronic relaxation due to the BSSE removal by means of distance indices between the uncorrected and corrected charge densities. It is shown that BSSE contamination is more important at the DFT level of theory, and in some cases, changes on the topology of the electron density are observed upon BSSE correction. Inclusion of diffuse functions have been found to dramatically decrease the BSSE effect in both geometry and electron density. The CHA method represents a good compromise to obtain accurate results with small basis sets. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Molecular interaction energies and optimal configuration of a cubane dimer
Authors: Nikolaev Alexander V. , Verberck Bart , Ionova Galina V. 
Published: April 2009

AbstractWe have studied the dependence of the binding energy of a cubane dimer on the mutual orientation of and the distance between the composing monomers employing the second‐order Møller–Plesset perturbation scheme (MP2) with the cc‐pVDZ molecular basis set. We have found that the MP2 contribution from the molecular correlations is responsible for the bound state of the cubane dimer, whereas the Hartree–Fock contribution remains anti‐bonding at all intermolecular distances. Starting with two molecules in the standard orientation and centers of mass at (0,0,0) and (0,0,d), respectively, the maximal binding energy is found at d = 5.125 Å and one of the monomers rotated by 45° about the z‐axis. This configuration implies that the hydrogen atoms belonging to different monomers tend to repel each other. The results are in agreement with experimental data on the optimal packing of cubane molecules in the solid state. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Convergence acceleration techniques for non‐Hermitian SCF problems
Authors: Salvador Pedro 
Published: April 2009

AbstractConventional convergence acceleration techniques for the SCF procedure like the direct inversion in the iterative subspace and the level‐shifting can not be applied in the general case of non‐Hermitian Fock operators. The commutator of the Fock matrix and the density matrix do not vanish upon convergence of non‐Hermitian SCF equations and hence the usual error vector choice is not applicable. In this work we describe in detail the implementation of these convergence acceleration techniques for the non‐Hermitian case. We focus in particular in the solution of the CHA‐SCF equations (arising from the application of the chemical Hamiltonian approach at the Hartree–Fock level of theory), but it can be generalized to any non‐Hermitian SCF problem. It is shown that a general commutation relationship combining the right and left eigenvectors of the Fock matrix is appropriate as error vector. In a similar fashion, level‐shifting techniques of the virtual orbitals can be easily implemented as well. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
International operations and sustainable development: Should national culture matter?
Authors: Vachon Stephan 
Published: April 2009

AbstractAs manufacturers around the world have seen an increasing number of opportunities to produce abroad and to source from low cost regions, they also have had to address growing pressure from non‐governmental organizations, consumer groups and even the population in general regarding sustainable development. This paper examines the conjuncture of these two trends by assessing the linkage between national culture and corporate sustainable development practices in 55 countries. The results suggest that two of Hofstede's national culture dimensions are linked to a higher degree of sustainable practices by corporations. In particular, a nation's high degree of individualism and uncertainty avoidance were both related to green corporatism, environmental innovation, fair labor practices and corporate social involvement. The results provide managers with another tool in making decisions about offshoring, global sourcing and international production expansion. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Bone Marrow Mononuclear Cells Have Neurovascular Tropism and Improve Diabetic Neuropathy
Authors: Kim Hyongbum , Park Jong-seon , Choi Yong Jin , Kim Mee-Ohk , Huh Yang Hoon , Kim Sung-Whan , Han Ji Woong , Lee JiYoon , Kim Sinae , Houge Mackenzie A. , Ii Masaaki , Yoon Young-sup 
Published: April 2009

Abstract
Bone marrow-derived mononuclear cells (BMNCs) have been shown to effectively treat ischemic cardiovascular diseases. Because diabetic neuropathy (DN) is causally associated with impaired angiogenesis and deficiency of angiogenic and neurotrophic factors in the nerves, we investigated whether DN can be ameliorated by local injection of BMNCs. Severe peripheral neuropathy, characterized by a significant decrease in the motor and sensory nerve conduction velocities (NCVs), developed 12 weeks after the induction of diabetes with streptozotocin in rats. The injection of BMNCs restored motor and sensory NCVs to normal levels and significantly improved vascular density and blood flow in diabetic nerves over 4 weeks. Fluorescent microscopic observation revealed that DiI-labeled BMNCs preferentially engrafted in sciatic nerves. Whole-mount fluorescent imaging and confocal microscopic evaluation demonstrated that many of the BMNCs localized following the course of the vasa nervorum in close proximity to blood vessels without incorporation into vasa nervorum as endothelial cells at a detectable level. Real-time reverse transcription-polymerase chain reaction analysis showed that the levels of angiogenic and neurotrophic factors were significantly increased in the nerves by BMNC injection. Local transplantation of BMNCs improved experimental DN by augmenting angiogenesis and increasing angiogenic and neurotrophic factors in peripheral nerves. These findings suggest that BMNC transplantation may represent a novel therapeutic option for treating DN.
Disclosure of potential conflicts of interest is found at the end of this article.
Zinc Finger Protein 191 (ZNF191/Zfp191) Is Necessary to Maintain Neural Cells As Cycling Progenitors
Authors: Khalfallah Olfa , Ravassard Philippe , Lagache Che Serguera , Fligny Cécile , Serre Angéline , Bayard Elisa , Faucon-Biguet Nicole , Mallet Jacques , Meloni Rolando , Nardelli Jeannette 
Published: April 2009

Abstract
The identification of the factors that allow better monitoring of stem cell renewal and differentiation is of paramount importance for the implementation of new regenerative therapies, especially with regard to the nervous and hematopoietic systems. In this article, we present new information on the function of zinc finger protein 191 (ZNF/Zfp191), a factor isolated in hematopoietic cell lines, within progenitors of the central nervous system (CNS). ZNF/Zfp191 has been found to be principally expressed in progenitors of the developing CNS of humans and mice. Such an overlap of the expression patterns in addition to the high homology of the protein in mammals suggested that ZNF/Zfp191 exerts a conserved function within such progenitors. Indeed, ZNF191 knockdown in human neural progenitors inhibits proliferation and leads to the exit of the cell cycle. Conversely, ZNF191 misexpression maintains progenitors in cycle and exerts negative control on the Notch pathway, which prevents them from differentiating. The present data, together with the fact that the inactivation of Zfp191 leads to embryonic lethality, confirm ZNF191 as an essential factor acting for the promotion of the cell cycle and thus maintenance in the progenitor stage. On the bases of expression data, such a function can be extended to progenitor cells of other tissues such as the hematopoietic system, which emphasizes the important issue of further understanding the molecular events controlled by ZNF/Zfp191.
Disclosure of potential conflicts of interest is found at the end of this article.
Prognostic Factors and Analysis of S100a4 Protein in Resected Pulmonary Metastases from Renal Cell Carcinoma
Authors: Bandiera Alessandro , Melloni Giulio , Freschi Massimo , Giovanardi Michele , Carretta Angelo , Borri Anna , Ciriaco Paola , Zannini Piero 
Published: April 2009

AbstractBackgroundThis study analyzes our experience with pulmonary resection for metastases from renal cell carcinoma. The goals were to search for factors influencing prognosis and to investigate the presence and the prognostic value of S100A4 protein in lung metastases and corresponding primary renal tumors.MethodsSixty‐five patients underwent surgical resection for renal and pulmonary lesions between 1992 and 2007. S100A4 protein expression was immunohistochemically examined in the peritumoral infiltrate of 64 lesions (32 metastases and the 32 corresponding primary carcinomas).ResultsOverall 3‐, 5‐, and 10‐year survival rates were 58, 46, and 25%, respectively. Univariate analysis revealed that surgical radicality (p = 0.0039) and stratification into groups according to the International Registry of Lung Metastases classification (p = 0.0137) were prognostic factors. Multivariate analysis confirmed that this classification was a significant prognostic factor (p = 0.01). All metastases and the corresponding primary carcinomas expressed S100A4 protein. Twenty‐one metastases (66%) had weak expression and 11 (34%) had strong expression. Twelve (37.5%) primary lesions had weak expression and 20 (62.5%) had strong expression. The 5‐year survival rate for patients with strong expression in primary carcinoma was 41%, significantly lower than that of patients with weak expression (78%; p = 0.05).ConclusionsPulmonary resection in metastatic renal cell carcinoma results in long‐term survival. Complete resection and stratification into groups according to the International Registry of Lung Metastases classification were prognostic factors. Overexpression of S100A4 protein in primary tumors was correlated with a poor prognosis. If confirmed in larger studies this finding could be used to schedule adjuvant treatments in patients undergoing nephrectomy for renal cell carcinoma.