bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of antioxidative properties of Allium species growing wild in Italy
Authors: Nencini Cristina , Cavallo Federica , Capasso Anna , Franchi Gian Gabriele , Giorgio Giorgi , Micheli Lucia 
Published: May 2007

AbstractThe genus Allium (Alliaceae) is an important dietary source of antioxidant phytochemical products. The antioxidant activity of some Allium species is well known but no information is available on the in vitro antioxidant activities of Italian Allium species growing wild. The aim of this study was to examine the in vitro antioxidant activity of aqueous extracts of different parts belonging to three Allium species growing wild, endemic to Italian flora: Allium neapolitanum Cyr., Allium subhirsutum L. and Allium roseum L., compared with the in vitro antioxidant activity of aqueous extracts of bulbs and leaves of the greatly studied garlic (Allium sativum L.). The antioxidant potential of extracts was evaluated using two different spectrophotometric assays: the DPPH test and FRAP assay. Furthermore the polyphenolic content was determined in all Allium species. The flowers of species growing wild showed the higher antioxidant power. Interesting results were shown even by the leaves, while the antioxidant capacity of the bulbs was lower. A correlation between the phenolic contents and the antioxidant activity was discovered. The differences in antioxidant capacity reflect the variability in the Allium species and the parts of the plant used and that the bulb of Allium sativum did not show higher antioxidant power. Copyright © 2007 John Wiley & Sons, Ltd.
Acanthopanax senticosus inhibits nitric oxide production in murine macrophages In Vitro and In Vivo
Authors: Lin Qiu‐Ye , Jin Li‐Ji , Ma Yong‐Sheng , Shi Ming , Xu Yong‐Ping 
Published: May 2007

AbstractExcess nitric oxide (NO) production has been implicated in inflammatory diseases. The present study investigated the inhibitory effect of the stem bark extract of Acanthopanax senticosus (A. senticosus) on NO production in murine macrophages in vitro and in vivo. In vitro exposure of RAW264.7 cells to 1, 10, 50, 100, 250, 500 and 1000 µg/mL of A. senticosus extract significantly suppressed NO production induced by lipopolysaccharide (LPS) and interferon gamma (IFN‐γ) in a dose‐dependent manner. In vitro exposure of mouse resident peritoneal macrophages to 1, 10, 100 and 1000 µg/mL of A. senticosus extract significantly suppressed NO production induced by LPS and IFN‐γ in a dose‐dependent manner. In vivo administration of A. senticosus extract (50, 100 and 200 mg/kg) to KM mice dose‐dependently inhibited LPS and IFN‐γ induced production of NO in isolated mouse peritoneal macrophages ex vivo. Exposure to A. senticosus extract had no effect on cell viability and systemic toxicity. The results demonstrated that the stem bark extract of A. senticosus extract inhibits NO production in murine macrophages in vitro and in vivo. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of effects of the herbal preparation circulat on gene expression levels in cultured human fibroblasts
Authors: Antoshechkin A. , Olalde J. , Magarici M. , Muhammad A. , Salom A. , Suarez J. , Amendola F. 
Published: May 2007

AbstractCirculat is a systemic standardized plant extract formulation that was developed for the prevention of severe manifestations of type 2 diabetes such as necrotic damage of the plantar foot. With the aim of revealing the molecular mechanisms underlying Circulat's biological activity, the effects of Circulat treatment on gene expression levels were examined in the cultured human fibroblast cell line MRC‐5 using Affymetrix oligonucleotide microarrays. The analysis identified 187 genes, the expression levels of which underwent significant changes upon Circulat treatment. These include four genes (IL6, HMGA1, SLC19A2 and C4A) that have been implicated previously in the development of diabetes. A large proportion of the identified genes are involved in energy metabolism, protein synthesis, glucose metabolism and signaling pathways. Synergistic action of the Circulat components has also been revealed. Prospective applications of microarray analysis in phytopharmacology are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Hypochlorous acid scavenging capacity of garlic
Authors: Pedraza‐Chaverrí José , Arriaga‐Noblecía Gabriela , Medina‐Campos Omar Noel 
Published: May 2007

AbstractThe ability of the following aqueous garlic extracts to scavenge hypochlorous acid (HOCl) was studied: (a) unheated extract of raw garlic (RG), (b) heated extract of raw garlic (HRG), (c) extract of boiled garlic cloves (BG) and (d) extract of microwave‐treated garlic cloves (MG). The HOCl scavenging activity was evaluated following changes in the absorption spectrum of catalase (370–450 nm). RG, HRG and BG scavenged HOCl in a concentration‐dependent way: the IC50 (mg/mL) values for RG, HRG and BG were 0.339 ± 0.028, 0.632 ± 0.030 and 0.690 ± 0.031, respectively. The HOCl scavenging ability of garlic was significantly decreased when garlic cloves or the extract of raw garlic were heated (BG and HRG, respectively); this scavenging ability was eliminated when garlic was subjected to microwave heating (MG). The IC50 value for the reference compound, ascorbic acid, was 0.500 ± 0.049 mg/mL. In summary, raw garlic concentration‐dependently scavenged HOCl; this ability was eliminated in extracts of microwave‐treated garlic cloves but not in heated extracts of raw garlic or extracts of boiled garlic cloves. Copyright © 2007 John Wiley & Sons, Ltd.
The electronic structure of molybdenum (II) clusters with chelate ligands
Authors: Yusha Sergei N. , Projavkin Alexander A. , Dementyev Ilia A. , Kozin Andrei O. , Korolkov Dmitry V. 
Published: May 2007

AbstractThe electronic structures of divalent molybdenum binuclear clusters with chelate ligands [Mo2(O2CH)4], [Mo2(O2CCH3)4], [Mo2(O2CCF3)4], [Mo2(O2CCFH2)4], [Mo2(O2CCOOH)4], and [Mo2(SO4)4]4− are calculated and interpreted using theory of density functional; one‐electron redox reactions and addition reactions for these clusters are modeled. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The influence of molecular structure on the change of the arrhenius factor of gas‐phase elimination of nitric acid from nitroalkanes
Authors: Shamsutdinov A. F. , Shamsutdinov T. F. , Chachkov D. V. , Shamov A. G. , Khrapkovskii G. M. 
Published: May 2007

AbstractThe Arrhenius factor of gas‐phase elimination of nitric acid from nitrocompounds was estimated. Asymmetric internal rotation was taken into account. To this end, an appropriate mathematical apparatus was developed. The geometry, transition state, rotation barriers and vibration frequencies were found by the density functional theory method B3LYP/6‐31G(d) by means Gaussian 98 program. The influence of the molecular structure on the Arrhenius factor was considered. The reaction barriers were estimated theoretically. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Atomic structure under external confinements: Effect of plasma
Authors: Sil A. N. , Bhattacharyya S. , Mukherjee P. K. 
Published: May 2007

AbstractExtensive nonrelativistic studies have been performed on the spectral properties of confined atomic systems under a charge neutral background. The effect of confinement on the spectral properties due to the neutral background has been analyzed using plasma model, which, for weak coupling case, can be obtained from the standard Debye screening model, and for strong coupling case, can be envisaged by ion sphere (IS) model. Further consideration has been given for estimating the effect due to spatially confined plasma, which is obtained by imposing finite boundary conditions on the wave functions. Several atomic, ionic, and exotic systems have been considered for our exclusive study. The structural properties like the ground and excited state energies, oscillator strengths, and transition probabilities for low lying excitations and spectral line shifts have been estimated for hydrogen‐ and helium‐like ions under different plasma coupling strengths. The system approaches towards gradual instability with increase of the plasma coupling strength. A gradual reduction of the ionization potential is observed and the number of bound states become finite. The behavior of ionization potentials, excitation energies, polarizabilities, oscillator strengths, and transition probabilities with respect to increased plasma strength have been found to be interesting. Our findings are in good agreement with limited experimental observations using laser produced plasmas. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Non–Born–Oppenheimer calculations of the ground state of H3
Authors: Cafiero Mauricio , Adamowicz Ludwik 
Published: May 2007

AbstractWe present quantum–mechanical calculations for the ground state of the H3 system performed without the Born‐Oppenehimer approximation. In the calculations we use explicitly correlated Gaussian basis functions that explicitly depend on all of the interparticle distances. These basis functions allow us to achieve high accuracy while explicitly describing nucleus–nucleus, nucleus–electron, and electron–electron correlation effects. Gaussian basis sets ranging in size from 85 to 950 functions have been optimized using a gradient‐based procedure. The issue of defining and extracting the H3 molecular structure based on the non‐BO wave function is also discussed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Quantum chemical simulation of cytochrome P450 catalyzed aromatic oxidation: Metabolism, toxicity, and biodegradation of benzene derivatives
Authors: D'Yachkov P. N. , Kharchevnikova N. V. , Dmitriev A. V. , Kuznetsov A. V. , Poroikov V. V. 
Published: May 2007

AbstractThe dependences of biological oxidation and toxicity of the mono‐ and multi‐substituted benzene derivatives on the nature of substituents are studied using an oxenoid model and the quantum chemical calculations. According to this model, the P450 enzyme breaks the dioxygen molecules and generates the active atomic oxygen species (oxens); these species readily react with substrates. Using MO LCAO MNDO approach, we calculated the differences ΔE of the total energies of aromatic compounds and corresponding arene oxides containing tetrahedrally coordinated carbon atoms. We obtained that the ΔE values determine the positions of the enzyme mediated oxidation, rate of substrate biotransformation, and toxicity of the benzene derivatives. In addition to the “dynamic” reactivity index ΔE related to the enzyme‐mediated substrate biotransformation, we calculated many standard “static” reactivity indices, corresponding to the substrate molecules in the starting equilibrium geometry (the energies of the occupied and unoccupied MOs, the effective atomic charges, the free valence indices, and the superdelocalizabilities). The arene oxide stability ΔE parameter is shown to be the most adequate characteristic of both the biological oxidation process and toxicity of benzenes. The ΔE parameters were also used successfully to describe the features of di‐ and tri‐chlorinated biphenyls bacterial metabolism. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Xα‐DVM study of properties of active sites of hemoglobin upon substitution of Fe by other 3d‐metal atoms
Authors: Yuryeva Elmira I. 
Published: May 2007

AbstractThe aim of this study is to investigate changes in functional properties of active sites of deoxyhemoglobin upon substitution of Fe by the other 3d‐metal atoms. Relationships between parameters of electronic structure, chemical binding, and temperatures of structure stability loss of active sites of α‐ and β‐subunits of deoxyhemoglobin are estimated using the Xα‐DV method. It is shown that the calculation technique of the temperature Tm of structure stability loss of active sites of deoxyhemoglobin based on the thermodynamic uncertainty relation gives a reasonable interpretation of the maximal possible temperature for a human body living. Temperatures of structure stability loss are higher for Cr, Mn atoms (89, 42 °C) and lower for Co, Ni, Cu, Zn (40, 37, 33, 29 °C) in comparison with Fe (41 °C). Thus the calculations performed show that the temperature of structure stability loss is controlled both by the type of the 3d atom carrying oxygen and small structural differences in active sites of α‐ and β‐subunits of deoxyhemoglobin. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The strong chromatic number of a graph
Authors: Alon Noga 
Published: May 2007

AbstractIt is shown that there is an absolute constant c with the following property: For any two graphs G1 = (V, E1) and G2 = (V, E2) on the same set of vertices, where G1 has maximum degree at most d and G2 is a vertex disjoint union of cliques of size cd each, the chromatic number of the graph G = (V, E1 U E2) is precisely cd. The proof is based on probabilistic arguments.
Gap‐Free Set Partitions
Authors: Goh William M. Y. , Schmutz Eric 
Published: May 2007

AbstractA set partition is called “gap‐free” if its block sizes form an interval. In other words, there is at least one block of each size between the smallest and largest block sizes. Let B(n) and G(n), respectively, denote the number of partitions and the number of gap‐free partitions of the set [n]. We prove thatmagnified image
Excluding Induced Subgraphs III: A General Asymptotic
Authors: Prömel H. J. , Steger A. 
Published: May 2007

AbstractIn this article we study asymptotic properties of the class of graphs not containing a fixed graph H as an induced subgraph. In particular we show that the number Forbn★(H) of such graphs on n vertices is essentially determined by the number of subgraphs of a single graph. This implies thatmagnified imageWhere t(H) is a graph‐theoretic parameter generalizing the chromatic number and the clique covering number. This result complements a theorem of Erdös, Frankl, and Rödl [2] who showed that the number Forbn(H) of graphs on n vertices which do not contain H as a weak subgraph is given bymagnified image
Probabilities of Sentences about Very Sparse Random Graphs
Authors: Lynch James F. 
Published: May 2007

AbstractWe consider random graphs with edge probability βn−α, where n is the number of vertices of the graph, β > 0 is fixed, and α = 1 or α = (l + 1) /l for some fixed positive integer l. We prove that for every first‐order sentence, the probability that the sentence is true for the random graph has an asymptotic limit.
The Evolution of Random Subgraphs of the Cube
Authors: Bollobás B. , Kohayakawa Y. , Łuczak T. 
Published: May 2007

Abstract be a random Qn”‐process, that is let Q0 be the empty spanning subgraph of the cube Qn and, for 1 ⩽ t ⩽ M = nN/2 = n2n−1, let the graph Qt be obtained from Qt−1 by the random addition of an edge of Qn not present in Qt−1. When t is about N/2, a typical Qt undergoes a certain “phase transition'': the component structure changes in a sudden and surprising way. Let t = (1 + ϵ) N/2 where ϵ is independent of n. Then all the components of a typical Qt have o(N) vertices if ϵ < 0, while if ϵ > 0 then, as proved by Ajtai, Komlós, and Szemerédi, a typical Qt has a “giant” component with at least α(ϵ)N vertices, where α(ϵ) > 0. In this note we give essentially best possible results concerning the emergence of this giant component close to the time of phase transition. Our results imply that if η > 0 is fixed and t ⩽ (1 − n−η) N/2, then all components of a typical Qt have at most nβ(η) vertices, where β(η) > 0. More importantly, if 60(log n)3/n ⩽ ϵ = ϵn = o(1), then the largest component of a typical Qt has about 2ϵN vertices, while the second largest component has order O(nϵ−2). Loosely put, the evolution of a typical Qn process is such that shortly after time N/2 the appearance of each new edge results in the giant component acquiring 4 new vertices.
Volumes Spanned by Random Points in the Hypercube
Authors: Dyer M. E. , Füredi Z. , McDiarmid C. 
Published: May 2007

AbstractConsider the hypercube [0, 1]n in Rn. This has 2n vertices and volume 1. Pick N = N(n) vertices independently at random, form their convex hull, and let Vn be its expected volume. How large should N(n) be to pick up significant volume? Let k=2/√≈1.213, and let ϵ > 0. We shall show that, as n→∞, Vn→0 if N(n)⩽(k−ϵ)n →1 if N(n) ⩾ (k + ϵ)n. A similar result holds for sampling uniformly from within the hypercube, with constant .
The Forwarding Indices of Random Graphs
Authors: Fernandez de la Vega W. , Gordones L. Marquez 
Published: May 2007

AbstractA routing R of a graph G is a set of n(n − 1) elementary paths R(u, v) specified for all ordered pairs (u, v) of vertices of G. The vertex‐forwarding index ξ(G) of G, is defined bymagnified imageWhere ξ(G, R) is the maximum number of paths of the routing R passing through any vertex of G and the minimum is taken over all the routings of G. Let Gp denote the random graph on n vertices with edge probability p and let m = np. It is proved among other things that, under natural growth conditions on the function p = p(n), the ratiomagnified imageTends to 1 in probability as n tends to infinity.
Almost all cubic graphs are Hamiltonian
Authors: Robinson R. W. , Wormald N. C. 
Published: May 2007

AbstractIn a previous article the authors showed that at least 98.4% of large labelled cubic graphs are hamiltonian. In the present article, this is improved to 100% in the limit by asymptotic analysis of the variance of the number of Hamilton cycles with respect to populations of cubic graphs with fixed numbers of short odd cycles.
Probabilistic construction of proportional graphs
Authors: Janson Svante , Spencer Joel 
Published: May 2007

AbstractProportional graphs are constructed for any rational p ϵ (0, 1) by a probabilistic method: it is shown that a certain random graph may with positive probability be adjusted so as to become proportional. The construction uses a novel type of random graph, where the number of edges is fixed but, nevertheless, the edges appear independently in rather large sets of possible edges.
On the Travelling Salesperson Problem in Many Dimensions
Authors: Rhee Wansoo T. 
Published: May 2007

AbstractConsider d ⩾ 2, and m points X1, …, Xm that are independent uniformly distributed in [0, 1]d. It is well known that the length Tm of the shortest tour through X1, …, Xm satisfies limm→∞ E(Tm)/m1−1/d = β(d) for a certain number β(d). We show that for some numerical constant K,

.
Chain Lengths in Certain Random Directed Graphs
Authors: Newman Charles M. 
Published: May 2007

AbstractWe study the random directed graph with vertex set {1, …, n} in which the directed edges (i, j) occur independently with probability cn/n for i<j and probability zero for i ⩽ j. Let Mn (resp., Ln) denote the length of the longest path (resp., longest path starting from vertex 1). When cn is bounded away from 0 and ∞ as n→∞, the asymptotic behavior of Mn was analyzed in previous work of the author and J. E. Cohen. Here, all restrictions on cn are eliminated and the asymptotic behavior of Ln is also obtained. In particular, if cn/ln(n)→∞ while cn/n→0, then both Mn/cn and Ln/cn are shown to converge in probability to the constant e.
Refined Approximations for the Ewens Sampling Formula
Authors: Barbour A. D. 
Published: May 2007

AbstractThe Ewens sampling formula is a family of probability distributions over the space of cycle types of permutations ofnobjects, indexed by a real parameter θ. In the case θ = 1, where the distribution reduces to that induced by the uniform distribution on all permutations, the joint distributions of the numbers of cycles of lengths less thanb = o(n)is extremely well approximated by a product of Poisson distributions, having mean 1/jfor cycle lengthj: the error is super‐exponentially small withnb−1. For θ ≠ 1. the analogous approximation, with means adjusted to θ/j, is good, but with error only linear inn−1b. In this article, it is shown that, by choosing the means of the Poisson distributions more carefully, an error quadratic inn−1bcan be achieved, and that essentially nothing better is possible.
1‐Pancyclic Hamilton Cycles in Random Graphs
Authors: Cooper C. 
Published: May 2007

AbstractWe consider a generalization of the pancyclic property. A graph G is defined to be 1‐pancyclic if there is some Hamilton cycle H in G such that we can find a cycle Cs of length s (3 ⩽ s ⩽ n − 1) using only the edges of H and one other edge es. We show that the threshold for Gn,p to be Hamiltonian, is the threshold for the 1‐pancyclic property.
Simple Constructions of Almost k‐wise Independent Random Variables
Authors: Alon Noga , Goldreich Oded , Håstad Johan , Peralta René 
Published: May 2007

AbstractWe present three alternative simple constructions of small probability spaces onnbits for which anykbits are almost independent. The number of bits used to specify a point in the sample space is (2 +o(1)) (log logn+k/2 + logk+ log 1/ϵ), where ϵ is the statistical difference between the distribution induced on anykbit locations and the uniform distribution. This is asymptotically comparable to the construction recently presented by Naor and Naor (our size bound is better as long as ϵ < 1/(klogn)). An additional advantage of our constructions is their simplicity.
Generalized Digital Trees and Their Difference—Differential Equations
Authors: Flajolet Philippe , Richmond Bruce 
Published: May 2007

AbstractConsider a tree partitioning process in which n elements are split into b at the root of a tree (b a design parameter), the rest going recursively into two subtrees with a binomial probability distribution. This extends some familiar tree data structures of computer science like the digital trie and the digital search tree. The exponential generating function for the expected size of the tree satisfies a difference–differential equation of order b,magnified imageThe solution involves going to ordinary (rather than exponential) generating functions, analyzing singularities by means of Mellin transforms and contour integration. The method is of some general interest since a large number of related problems on digital structures can be treated in this way via singularity analysis of ordinary generating functions.
Limit Theorems for Combinatorial Structures via Discrete Process Approximations
Authors: Arratia Richard , Tavaré Simon 
Published: May 2007

AbstractDiscrete functional limit theorems, which give independent process approximations for the joint distribution of the component structure of combinatorial objects such as permutations and mappings, have recently become available. In this article, we demonstrate the power of these theorems to provide elementary proofs of a variety of new and old limit theorems, including results previously proved by complicated analytical methods. Among the examples we treat are Brownian motion limit theorems for the cycle counts of a random permutation or the component counts of a random mapping, a Poisson limit law for the core of a random mapping, a generalization of the Erdös–Turán Law for the log‐order of a random permutation and the smallest component size of a random permutation, approximations to the joint laws of the smallest cycle sizes of a random mapping, and a limit distribution for the difference between the total number of cycles and the number of distinct cycle sizes in a random permutation.
The Variance of Level Numbers in Certain Families of Trees
Authors: Gutjahr W. J. 
Published: May 2007

AbstractFor the families of t‐ary trees and planted plane trees, the variance of the level numbers (i.e., the depths of specified endnodes) is determined. We apply different types of techniques, such as singularity analysis (Kirschenhofer's diagonalization method) or a probabilistic approach using weak convergence and uniform integrability. In the case of binary trees, an exact variance formula for finite tree size is established; in the other cases, asymptotic equivalents are derived. Also some results on higher moments are presented.