bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upper chromatic number of finite projective planes
Authors: Bacsó Gábor , Tuza Zsolt 
Published: September 2007

AbstractFor a finite projective plane $\Pi$, let $\bar {\chi} (\Pi)$ denote the maximum number of classes in a partition of the point set, such that each line has at least two points in the same partition class. We prove that the best possible general estimate in terms of the order of projective planes is $q^2-q-\Theta(\sqrt q)$, which is tight apart from a multiplicative constant in the third term ${\sqrt q}$:

As $q\to\infty, \bar {\chi}({\Pi}) \leq q^2-q-\sqrt q/2 +o(\sqrt q)$ holds for every projective plane $\Pi$ of order q.
If q is a square, then the Galois plane of order q satisfies $\bar{\chi}(PG(2,q))\geq q^2-q-2\sqrt q $.
Our results asymptotically solve a ten‐year‐old open problem in the coloring theory of mixed hypergraphs, where $\bar {\chi}(\Pi)$ is termed the upper chromatic number of $\Pi$. Further improvements on the upper bound (1) are presented for Galois planes and their subclasses. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 221–230, 2008
Importance of Ezh2 polycomb protein in tumorigenesis process interfering with the pathway of growth suppressive key elements
Authors: Tonini Tiziana , D'Andrilli Giuseppina , Fucito Alfredo , Gaspa Leonardo , Bagella Luigi 
Published: September 2007

AbstractAn understanding of the mechanisms that uncover the dynamic changes in the distribution of the chromatin modifying enzymes and regulatory proteins on their target loci could provide further insight into the phenomenon of malignant transformation. Based on the current available data, it seems more and more clear that an abnormal expression of Ezh2, a member of the Polycomb group (PcG) protein, may be involved in the tumorigenesis process, in addition, different studies identify Ezh2 as a potential marker that distinguish aggressive prostate and breast cancer from indolent one. Recent investigation show that ectopic expression of Ezh2 provides proliferative advantage to primary cells through interaction with the pathways of key elements that control cell growth arrest and differentiation, like members of the retinoblastoma (Rb) family. Here, we outline how these pathways converge and we review the recent advances on the molecular mechanisms that promote cell cycle progression through deregulation of Ezh2 protein level, providing novel links between cancer progression and chromatin remodeling machineries. J. Cell. Physiol. 214: 295–300, 2008. © 2007 Wiley‐Liss, Inc.
The Helicobacter pylori's protein VacA has direct effects on the regulation of cell cycle and apoptosis in gastric epithelial cells
Authors: Manente L. , Perna A. , Buommino E. , Altucci L. , Lucariello A. , Citro G. , Baldi A. , Iaquinto G. , Tufano M.A. , De Luca A. 
Published: September 2007

AbstractIn this study, we have evaluated the effects on cell cycle regulation of VacA alone and in combination with other two Helicobacter pylori proteins, cytotoxin‐associated protein (CagA) and HspB, using the human gastric epithelial cells (AGS). Our results indicate that VacA alone was able to inhibit the G1 to S progression of the cell cycle. The VacA capacity of inhibiting cell progression from G1 to S phase was also observed when cells were co‐transfected with CagA or HspB. Moreover, VacA over‐expression caused apoptosis in AGS cells through activation of caspase 8 and even more of caspase 9, thus indicating an involvement of both the receptor‐mediated and the mitochondrial pathways of apoptosis. Indeed, the two pathways probably can co‐operate to execute cell death with a prevalence of the mitochondrial pathways. Our data taken together provide additional information to further enhance our understanding of the molecular mechanism by which H. pylori proteins alter the growth status of human gastric epithelial cells. J. Cell. Physiol. 214: 582–587, 2008. © 2007 Wiley‐Liss, Inc.
In vitro activated human T lymphocytes very efficiently attach to allogenic multipotent mesenchymal stromal cells and transmigrate under them
Authors: Suva Domizio , Passweg Jakob , Arnaudeau Serge , Hoffmeyer Pierre , Kindler Vincent 
Published: September 2007

AbstractThe regulatory effect of human multipotent mesenchymal stromal cells (MSC) on allogenic T lymphocytes is extremely powerful and of important clinical relevance, but the mechanisms underlying this process are not fully elucidated. We report here that T lymphocytes activated with a sub‐mitogenic stimulus such as phytohemaglutinin alone (PHA), or with mitogenic stimuli such as PHA + interleukin‐2 (P‐IL2), or immobilized anti‐CD3 + anti‐CD28 mAb (a3‐28), tightly bound allogenic MSC and transmigrated within 4 h under them, where they remained for approximately 60 h. Allogenic MSC induced T cell proliferation in cultures containing sub‐mitogenic PHA concentrations, and inhibited the mitogenic effect of P‐IL2 or a3‐28. Anti‐γ‐IFN mAb or L‐tryptophan complementation partially restored proliferation in P‐IL2 and a3‐28 cultures, whereby γ‐IFN‐synthesizing CD3+ cells were detectable. MSC‐lymphocyte contact hindrance using transwells abrogated proliferation in PHA cultures, restored it integrally in P‐IL2 cultures, and partially in a3‐28 cultures. These data suggest that MSC‐induced T lymphocyte regulation results from the combination of various processes. Allogenic cell–cell contact, as demonstrated by the PHA co‐cultures is per se stimulatory, whereas γ‐IFN synthesized by activated T lymphocytes, which activates indolamine 2,3‐dioxygenase in MSC, and L‐tryptophan depletion, which is induced by this enzyme, are inhibitory. Transmigration is nevertheless pivotal for the establishment of the inhibition by these mediators because it targets lymphocytes under the stroma in small extracellular spaces surrounded by MSC, where L‐tryptophan is efficiently destroyed, leading to T lymphocyte proliferation arrest. In conclusion lymphocyte transmigration under allogenic MSC potentiates the inhibitory effect of soluble mediators generated by these cells. J. Cell. Physiol. 214: 588–594, 2008. © 2007 Wiley‐Liss, Inc.
Folinic acid attenuates methotrexate chemotherapy‐induced damages on bone growth mechanisms and pools of bone marrow stromal cells
Authors: Xian Cory J. , Cool Johanna C. , Scherer Michaela A. , Fan Chiaming , Foster Bruce K. 
Published: September 2007

AbstractChemotherapy often induces bone growth defects in pediatric cancer patients; yet the underlying cellular mechanisms remain unclear and currently no preventative treatments are available. Using an acute chemotherapy model in young rats with the commonly used antimetabolite methotrexate (MTX), this study investigated damaging effects of five once‐daily MTX injections and potential protective effects of supplementary treatment with antidote folinic acid (FA) on cellular activities in the tibial growth plate, metaphysis, and bone marrow. MTX suppressed proliferation and induced apoptosis of chondrocytes, and reduced collagen‐II expression and growth plate thickness. It reduced production of primary spongiosa bone, volume of secondary spongiosa bone, and proliferation of metaphyseal osteoblasts, preosteoblasts and bone marrow stromal cells, with the cellular activities being most severely damaged on day 9 and returning to or towards near normal levels by day 14. On the other hand, proliferation of marrow pericytes was increased early after MTX treatment and during repair. FA supplementation significantly suppressed chondrocyte apoptosis, preserved chondrocyte proliferation and expression of collagen‐II, and attenuated damaging effects on production of calcified cartilage and primary bone. The supplementation also significantly reduced MTX effects on proliferation of metaphyseal osteoblastic cells and of bone marrow stromal cells, and enhanced pericyte proliferation. These observations suggest that FA supplementation effectively attenuates MTX damage on cellular activities in producing calcified cartilage and primary trabecular bone and on pools of osteoblastic cells and marrow stromal cells, and that it enhances proliferation of mesenchymal progenitor cells during bone/bone marrow recovery. J. Cell. Physiol. 214: 777–785, 2008. © 2007 Wiley‐Liss, Inc.
Ore‐type condition for the existence of connected factors
Authors: Nam Yunsun 
Published: September 2007

AbstractIn this article, we obtain some Ore‐type sufficient conditions for a graph to have a connected factor with degree restrictions. Let α and k be positive integers with $\alpha \ge {{k + 1} \over{k - 1}}$ if ${{k}} \ge 2$ and $\alpha \ge 4$ if ${{k}}=1$. Let G be a connected graph with a spanning subgraph F, each component of which has order at least α. We show that if the degree sum of two nonadjacent vertices is greater than ${{2(\vert {G} \vert-\alpha-1)} \over {k+1}}$ then G has a connected subgraph in which F is contained and every vertex $v$ has degree at most ${\rm deg}_{{F}}(v)\,+\,{{k}}$. From the result, we derive that a graph G has a connected $[{{a}},{{b}}]$‐factor $({{b}}>{{a}})$ if the degree sum of two nonadjacent vertices is at least ${{2[(a+1)\vert{G}\vert-(a+2)]} \over {a + b}}$. © Wiley Periodicals, Inc. J. Graph Theory 56: 241–248, 2007
Modeling bone morphogenetic protein and bisphosphonate combination therapy in wild‐type and Nf1 haploinsufficient mice
Authors: Schindeler Aaron , Ramachandran Manoj , Godfrey Craig , Morse Alyson , McDonald Michelle , Mikulec Kathy , Little David G. 
Published: September 2007

AbstractRecombinant bone morphogenetic proteins (BMPs) show promise in treating the orthopedic complications associated with neurofibromatosis type 1 (NF1), such as congenital pseudarthrosis of the tibia. Minimal scientific information regarding the effects of BMP in the context of NF1 is available. As abnormalities in both bone formation and resorption have been documented in Nf1‐deficient mice, we hypothesized that inadequate BMP‐induced bone formation could be augmented by cotreatment with the bisphosphonate zoledronic acid (ZA). First, primary osteoblasts isolated from wild type (Nf1+/+) and Nf1‐deficient (Nf1+/−) mice were cultured in the presence and absence of BMP‐2. While Nf1+/− cells exhibited less osteogenic potential than Nf1+/+ cells, alkaline phosphatase expression and matrix mineralization for both genotypes were enhanced by BMP‐2 treatment. To model this response in vivo, 20 µg BMP‐2 was implanted intramuscularly into the quadriceps of mice to induce heterotopic bone. Radiographs revealed significantly less net bone formation in Nf1+/− mice compared to Nf1+/+ controls. To test the effect of an antiresorptive agent, mice were cotreated twice weekly from postoperative day 3 with 0.02 mg/kg ZA or with saline. ZA treatment led to a synergistic increase in the amount of heterotopic bone in both Nf1+/+ and Nf1+/− mice compared with saline controls, as measured by DEXA and histomorphometry. Thus, the anabolic deficiency noted in Nf1+/− mice is amenable to stimulation by BMP‐2, but mineralized tissue formation remains below that of Nf1+/+ controls. Bisphosphonate combination therapy is superior to BMP therapy alone in terms of net bone production in vivo in both wild‐type and Nf1‐deficient mice. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:65–74, 2008
Single‐cell gel electrophoresis: a tool for investigation of DNA protection or damage mediated by dietary antioxidants
Authors: Szeto Yim Tong 
Published: September 2007

AbstractOne method of assessing DNA damage is the comet assay, which was developed in 1988. The comet assay enables the detection of DNA strand breaks in individual cells. This test has also been used to study the in vitro and in vivo genotoxic or genoprotective effects of certain agents such as dietary antioxidants. This paper aims to consolidate the antioxidant and pro‐oxidant effects of a series of dietary agents which have been evaluated by comet assay. Copyright © 2007 Society of Chemical Industry
A linear‐time algorithm for the k‐fixed‐endpoint path cover problem on cographs
Authors: Asdre Katerina , Nikolopoulos Stavros D. 
Published: September 2007

AbstractIn this paper, we study a variant of the path cover problem, namely, the k‐fixed‐endpoint path cover problem. Given a graph G and a subset ${\cal T}$ of k vertices of V(G), a k‐fixed‐endpoint path cover of G with respect to ${\cal T}$ is a set of vertex‐disjoint paths ${\cal P}$ that covers the vertices of G such that the k vertices of ${\cal T}$ are all endpoints of the paths in ${\cal P}$. The k‐fixed‐endpoint path cover problem is to find a k‐fixed‐endpoint path cover of G of minimum cardinality; note that, if ${\cal T}$ is empty, that is, k = 0, the stated problem coincides with the classical path cover problem. We show that the k‐fixed‐endpoint path cover problem can be solved in linear time on the class of cographs. More precisely, we first establish a lower bound on the size of a minimum k‐fixed‐endpoint path cover of a cograph and prove structural properties for the paths of such a path cover. Then, based on these properties, we describe an algorithm which, for a cograph G on n vertices and m edges, computes a minimum k‐fixed‐endpoint path cover of G in linear time, that is, in O(n+m) time. The proposed algorithm is simple, requires linear space, and also enables us to solve some path cover related problems, such as the 1HP and 2HP, on cographs within the same time and space complexity. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(4), 231–240 2007
Approximability of the k‐server disconnection problem
Authors: Hong Sung‐Pil , Choi Byung‐Cheon 
Published: September 2007

AbstractConsider a network of k servers and their users. Each server provides a unique service that has a certain utility for each user. Now comes an attacker who wishes to destroy a set of network edges to maximize his net gain, namely the total disconnected utilities of the users minus the total edge‐destruction cost. This k‐server disconnection problem is NP‐hard and, furthermore, cannot be approximated within a polynomially computable factor of the optimum when k is part of the input. Even for any fixed k ≥ 2, there is a constant ϵ > 0 such that approximation of the problem within a factor 1/(1 + ϵ) of the optimum is NP‐hard. However, a (
${1\over 2}+{{1}\over {2^{k+1}-2}}$)‐approximation can be created in the time of O(2k) applications of a min‐cut algorithm. The main idea is to approximate the optimum with special solutions computable in polynomial time due to supermodularity. Therefore, when the the network has, as is usual in most cases, only a few servers, a 0.5‐approximation can be carried out in polynomial time. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(4), 273–282 2007
Synthesis of silicon‐bridged polythiophene derivatives and their applications to EL device materials
Authors: Ohshita Joji , Kimura Keisuke , Lee Kwang‐Hoi , Kunai Atsutaka , Kwak Young‐Woo , Son Eun‐Chul , Kunugi Yoshihito 
Published: September 2007

AbstractPalladium‐catalyzed oxidative homo‐coupling of 2,6‐bis(tributylstannyl)dithienosiloles with CuCl2 afforded poly(dithienosilole‐2,6‐diyl)s as novel polythiophene derivatives with intra‐chain silicon bridges, which exhibited red‐shifted UV absorption maxima by about 100 nm from those of the corresponding silole‐free polythiophenes. Alternate copolymers also were prepared by palladium‐catalyzed cross‐coupling reactions of 2,6‐dibromodithienosiloles with distannylthiophene or bithophene. These polymer films were applied to single and double‐layered organic electroluminescence devices. It was found that some of the resulting polymers exhibited electroluminescence properties and emitted red light in EL devices with the structure of ITO/polymer/Mg‐Ag. Introducing an electron‐transporting Alq3 layer between the polymer film and the Mg‐Ag cathode led to a remarkable improvement in the devices performance. An application of the copolymer to a field effect transistor was also studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4588–4596, 2007
Chapman rearrangement in the synthesis of aromatic polyamides
Authors: Burdukovskiy V. F. , Mognonov D. M. , Farion I. A. 
Published: September 2007

AbstractIt is established that N‐phenylsubstituted aromatic polyamides can be obtained via Chapman rearrangement of polybenzanyliminoesters synthesized by an interaction of bisphenols with imidoylchlorides. The rearrangements in melt or in film occur as a result of heating at 260–340 °C, and in a diphenyl ether solution rearrangement occurs at 240 °C. The resulting polymers are soluble in organic solvents and demonstrate high thermooxidative stability. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4656–4660, 2007
Alternating copolyfluorenevinyles with polynuclear aromatic moieties: Synthesis, photophysics, and electroluminescence
Authors: Mikroyannidis John A. , Fenenko Larysa , Yahiro Masayuki , Adachi Chihaya 
Published: September 2007

AbstractThree new copolymers, namely poly(fluorenevinylene‐alt‐naphthalenevinylene) (N), poly(fluorenevinylene‐alt‐anthracenevinylene) (A) and poly(fluorenevinylene‐alt‐pyrenevinylene) (P), were synthesized by Heck coupling of 9,9‐dihexyl‐2, 7‐divinylfluorene with a polynuclear aromatic dibromide. The 9,10‐disubstituted anthracene was obtained exclusively for A while N and P were obtained as a mixture of two isomers with predominant the 1,4‐disubstituted naphthalene and 1,8‐disubstituted pyrene, respectively. The polymers were soluble in common organic solvents and decomposed above 370 °C. Their glass transition temperature increased from 58 to 110 °C by increasing the number of the phenyl rings of the polynuclear aromatic moiety. Rather high‐efficiency blue and blue‐greenish photoluminescence (PL) of these copolymers in solution was largely decreased in their films, indicating the presence of concentration quenching in the solid state. The OLED using these polymers demonstrated green EL in the case of copolymers N and A, and red EL in the P derivative with ηEL = 0.26–0.31%. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4661–4670, 2007
A Diels‐Alder/retro Diels‐Alder strategy to synthesize polymers bearing maleimide side chains
Authors: Dispinar Tugba , Sanyal Rana , Sanyal Amitav 
Published: September 2007

AbstractPolymers containing thiol‐reactive maleimide groups on their side chains have been synthesized by utilization of a novel methacrylate monomer containing a masked maleimide. Diels‐Alder reaction between furan and maleimide was adapted for the protection of the reactive maleimide double bond prior to polymerization. AIBN initiated free radical polymerization was utilized for synthesis of copolymers containing masked maleimide groups. No unmasking of the maleimide group was evident under the polymerization conditions. The maleimide groups in the side chain of the polymers were unmasked into their reactive form by utilization of retro Diels‐Alder reaction. This cycloreversion was monitored by thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and 1H and 13C NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4545–4551, 2007
Luminescence properties and growth of pure and anthracene‐doped naphthalene crystals
Authors: Balamurugan N. , Arulchakkaravarthi A. , Ramasamy P. 
Published: September 2007

AbstractPure and anthracene‐doped naphthalene crystals of high quality with 20 mm diameter and 60 mm length have been grown by the self‐seeded vertical Bridgman method. The powder X‐ray diffraction studies and the Raman analysis show that the guest molecules appear as defects in the form of irregularly oriented molecules that do not significantly distort the monoclinic structure. The absorbance and fluorescence studies show high Stoke's shift for anthracene‐doped naphthalene crystals. From this we deduce that the exciting wavelength of the light (270 nm) is completely absorbed by the naphthalene, so that fluorescence from anthracene takes place as a result of energy transfer from naphthalene. The decay time observed for anthracene‐doped naphthalene is 27 ± 2 ns. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distribution of subgraphs of random regular graphs
Authors: Gao Zhicheng , Wormald N.C. 
Published: September 2007

AbstractWe obtain the asymptotic distribution of the number of copies of a fixed subgraph H in a random d‐regular graph, provided H is strictly balanced and d = d(n) is chosen so that the expected number of copies of H tends to infinity (but not too quickly), and the expected number of copies sharing edges with two other copies is bounded. The proof of asymptotic normality of the distribution uses a method of factorial moments for variables with unbounded means that was recently derived by the authors. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
On a universal best choice algorithm for partially ordered sets
Authors: Georgiou Nicholas , Kuchta Małgorzata , Morayne Michał , Niemiec Jarosław 
Published: September 2007

AbstractFor the only known universal best choice algorithm for partially ordered sets with known cardinality and unknown order (proposed by J. Preater) we improve the estimation of the lower bound of its chance of success from the hitherto known constant 1/8 to 1/4. We also show that this result is the best possible for this algorithm, i.e., the 1/4 bound cannot be further improved. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Large‐Scale Synthesis of Organophilic Zirconia Nanoparticles and their Application in Organic–Inorganic Nanocomposites for Efficient Volume Holography
Authors: Garnweitner Georg , Goldenberg Leonid M. , Sakhno Oksana V. , Antonietti Markus , Niederberger Markus , Stumpe Joachim 
Published: September 2007

AbstractWe present a multigram scale, one‐step nonaqueous synthesis route to monodisperse, highly crystalline ZrO2 nanoparticles. The nanoparticles can be stabilized in nonpolar solvents via a simple functionalization procedure using only minute amounts of organic stabilizers. Their great potential in materials applications is demonstrated by the fabrication of organic–inorganic nanocomposites that can be selectively photopolymerized to inscribe extremely effective and volume holographic gratings with the highest refractive index contrast (n1 of up to 0.024) achieved so far.
Experimentelle und numerische Untersuchungen von Knotenverbindungen für Tripods von Offshore‐Windenergieanlagen
Authors: Schaumann Peter , Keindorf Christian , Tomasch Frank 
Published: September 2007

AbstractIn dem Beitrag wird über Ergebnisse von experimentellen und numerischen Untersuchungen von Knotenverbindungen eines Tripods für Offshore‐Windenergieanlagen berichtet. Unter Annahme eines Referenzstandortes in der Ostsee (Kriegers Flak I) und einer Anlagengröße von 2 MW werden dazu repräsentative Berechnungen mit Hilfe von numerischen Modellen vorgestellt. Neben geschweißten Rohrknotenverbindungen werden auch Konstruktionsvarianten in Stahlguss analysiert und für die statischen und dynamischen Beanspruchungen dimensioniert. Im experimentellen Teil wird über die Durchführung und Auswertung von Ermüdungstests an Y‐Knoten mit und ohne Schweißnahtnachbehandlung berichtet. Dabei wird die Steigerung der Ermüdungsfestigkeit durch eine Nahtnachbehandlung mittels Ultrasonic Impact Treatment (UIT) bewertet. Die Versuchsergebnisse werden im Anschluss bei einer Neubewertung der Tripodknoten berücksichtigt.
Detaillösungen für ermüdungsbeanspruchte Tripod‐Gründungsstrukturen
Authors: Bergers Jennifer , Herion Stefan , Puthli Ram , Ummenhofer Thomas , Weich Imke 
Published: September 2007

AbstractIn diesem Aufsatz werden Untersuchungsergebnisse aus dem von der Forschungsvereinigung für Stahlanwendung e.V. finanzierten Projekt P633 – “Detaillösungen bei Ermüdungsfragen und dem Einsatz hochfester Stähle bei Türmen von Offshore‐Windenergieanlagen” vorgestellt. Neben allgemeinen Überlegungen und Versuchen zur Steigerung der Ermüdungsfestigkeit durch Einsatz von hochfesten Stählen in Kombination mit Schweißnahtnachbehandlungsverfahren, stand in diesem Projekt eine Strukturoptimierung eines Tripod‐Knotens im Vordergrund.