bluuebunny/crossref_metadata_2025 huggingface dataset:
NHERFs, NEP, MAGUKs, and more: Interactions that regulate PTEN
Authors: Bonifant Challice L. , Kim Jung‐Sik , Waldman Todd
Published: September 2007

This year marks the 10th anniversary of the discovery of the PTEN/MMAC1/TEP1 tumor suppressor gene (hereafter referred to as PTEN), one of the most commonly mutated genes in cancer. PTEN encodes a lipid phosphatase that dephosphorylates phosphoinositide‐3,4,5‐triphosphate (PIP3), thereby counteracting mitogenic signaling pathways driven by phosphoinositol‐3‐kinases (PI3K). By opposing PI3K signaling, PTEN inhibits the activation of the critical PI3K effector proteins Akt1‐3 (also known as protein kinase B or PKB). Given its central role in antagonizing PI3K signaling, one might expect that like PI3K, the activity of the PTEN protein would be highly regulated by numerous protein/protein interactions. However, surprisingly little is known about such interactions. This fact, combined with the generally accepted notion that phosphatases are less exquisitely regulated than kinases, has led to the idea that PTEN may function in a relatively unregulated fashion. Here we review the identities and proposed functions of known PTEN‐interacting proteins, and point out avenues of investigation that we hope may be fruitful in identifying important new mechanisms of PTEN regulation in mammalian cells. J. Cell. Biochem. 102: 878–885, 2007. © 2007 Wiley‐Liss, Inc.
Nuclear architecture: Is it important for genome function and can we prove it?
Authors: Mateos‐Langerak Julio , Goetze Sandra , Leonhardt Heinrich , Cremer Thomas , van Driel Roel , Lanctôt Christian
Published: September 2007

Gene regulation in higher eukaryotes has been shown to involve regulatory sites, such as promoters and enhancers which act at the level of individual genes, and mechanisms which control the functional state of gene clusters. A fundamental question is whether additional levels of genome control exist. Nuclear organization and large‐scale chromatin structure may constitute such a level and play an important role in the cell‐type specific orchestration of the expression of thousands of genes in eukaryotic cells. Numerous observations indicate a tight correlation between genome activity and nuclear and large‐scale chromatin structure. However, causal relationships are rare. Here we explore how these might be uncovered. J. Cell. Biochem. 102: 1067–1075, 2007. © 2007 Wiley‐Liss, Inc.
Upper chromatic number of finite projective planes
Authors: Bacsó Gábor , Tuza Zsolt
Published: September 2007

For 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

An 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

In 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

The 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

Chemotherapy 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

In 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

Recombinant 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

One 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

In 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

Consider 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

Palladium‐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

It 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

Three 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

Polymers 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

Pure 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

We 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

For 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

We 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

In 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

In 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.
Tragstruktur und Installation der Offshore‐Windenergieanlage Repower 5M
Authors: Seidel Marc
Published: September 2007

Im Sommer 2006 wurde in Schottland erstmals eine 5‐Megawatt‐Offshore‐Windenergieanlage (WEA) vom Typ REpower 5M in 45 m Wassertiefe errichtet. Die Tiefe des Wassers und weitere Standortbedingungen, die sich durch hohe Wellenbelastung und ungünstige Bodenverhältnisse auszeichnen, erforderten innovative Ansätze für die Tragstruktur und die Installation der REpower 5M. In diesem Beitrag wird über Entwurf, Fertigung und Montage der Jacket‐Strukturen für diese Windenergieanlage berichtet. Außerdem wird eine neuartige Montagemethode für die WEA beschrieben, bei der von einem Schwimmkran gearbeitet wurde. Die gewonnenen Erkenntnisse schaffen Grundlagen für die Errichtung größerer Stückzahlen von 5‐MW‐Windenergieanlagen in bislang nicht erschlossenen Wassertiefen größer als 20 m.
Alterations in IGF-I affect elderly: role of physical activity
Authors: Moran Sagiv , Chen Yamin , Ruthie Amir , Nir Yenon
Published: September 2007

The growth hormone–insulin-like growth factor I (IGF-I) axis is an important physiological regulator muscle for development. Although there is evidence that aging muscle retains the ability to synthesize IGF-I, there is also evidence that aging may be associated with attenuation of the ability of exercise to induce an isoform of IGF-I that promotes satellite cell proliferation. However, it is clear that overexpression of IGF-I in the muscle can protect against age-related sarcopenia. Strength training appears to be the intervention of choice for the prevention and treatment of sarcopenia. IGF-I has been implicated in the loss of the muscle with age, and IGF-I expression levels change as a consequence of strength training in older adults. However, it seems that advancing age, rather than declining serum levels of IGF-I, appears to be a major determinant of life-time changes in body composition in women and men. We concluded that resistive exercise is a significant determinant of muscle mass and function. Elevated levels of IGF-I have been found in physically active compared to sedentary individuals. Recent work suggests that IGF-I as a mediator plays an important role in muscle hypertrophy and angiogenesis, both of which characterize the anabolic adaptation of muscles to exercise.
The Paneitz equation in hyperbolic space
Authors: Ould Ahmedou Mohameden , Grunau Hans-Christoph , Reichel Wolfgang
Published: September 2007

The Paneitz operator is a fourth order differential operator which arises in conformal geometry and satisfies a certain covariance property. Associated to it is a fourth order curvature – the
Q
-curvature.

We prove the existence of a continuum of conformal radially symmetric complete metrics in hyperbolic space

\mathbb{H}^{n}

,

n > 4

, all having the same constant
Q
-curvature.

Moreover, similar results can be shown also for suitable non-constant prescribed
Q
-curvature functions.
Neuroprotective effects of (−)‐epigallocatechin‐3‐gallate (EGCG) on paraquat‐induced apoptosis in PC12 cells
Authors: Hou Rong‐Rong , Chen Jian‐Zong , Chen Hong , Kang Xiao‐Gang , Li Min‐Ge , Wang Bai‐Ren
Published: September 2007

Green tea, owing to its beneficial effect on health, is becoming more and more popular worldwide. (−)‐Epigallocatechin‐3‐gallate (EGCG), the main ingredient of green tea polyphenols, is a known protective effect on injured neurons in neurodegenerative disease, such as Alzheimer's disease and Parkinson's disease. Paraquat (PQ) is a widely used herbicide that possesses a similar structure to MPP+ and is toxic to mesencephalic dopaminergic neurons. In the present study, PQ‐injured PC12 cells were chosen as an in vitro cell model of Parkinson's disease and the neuroprotective effects of EGCG were investigated. The results showed that EGCG attenuated apoptosis of PC12 cells induced by PQ. The possible mechanism may be associated with maintaining mitochondrial membrane potential, inhibiting caspase‐3 activity and downregulating the expression of pro‐apoptotic protein Smac in cytosol. The present study supports the notion that EGCG could be used as a neuroprotective agent for treatment of neurodegenerative diseases.
Novel anti‐apoptotic effect of Bcl‐2: Prevention of polyamine depletion‐induced cell death
Authors: Holst C. Martina , Johansson Veronica M. , Alm Kersti , Oredsson Stina M.
Published: September 2007

The spermine analogue N1,N11‐diethylnorspermine (DENSPM) efficiently depletes the polyamine pools in the breast cancer cell line L56Br‐C1 and induces apoptotic cell death via the mitochondrial pathway. In this study, we have over‐expressed the anti‐apoptotic protein Bcl‐2 in L56Br‐C1 cells and investigated the effect of DENSPM treatment. DENSPM‐induced cell death was significantly reduced in Bcl‐2 over‐expressing cells. Bcl‐2 over‐expression reduced DENSPM‐induced release of the pro‐apoptotic proteins AIF, cytochrome c, and Smac/DIABLO from the mitochondria. Bcl‐2 over‐expression reduced the DENSPM‐induced activation of caspase‐3. Bcl‐2 over‐expression also prevented DENSPM‐induced Bax cleavage and reduction of Bcl‐XL and survivin levels. The DENSPM‐induced activation of the polyamine catabolic enzyme spermidine/spermine N1‐acetyltransferase was reduced by Bcl‐2 over‐expression, partly preventing polyamine depletion. Thus, Bcl‐2 over‐expression prevented a number of DENSPM‐induced apoptotic effects.
The relationship between impulsivity and Internet addiction in a sample of Chinese adolescents
Authors: Cao Fenglin , Su Linyan , Liu TieQiao , Gao Xueping
Published: September 2007

Objective

Previous studies regarding internet addiction have investigated associated psychological variables such as shyness, loneliness, self-consciousness, anxiety, depression and interpersonal relations. Few studies about the relationship between internet Addiction and impulsivity have been done. This study aimed to assess whether internet addiction is related to impulsivity among Chinese adolescents.

Method

This study was performed in two stages. We screened for the presence of internet Addiction among 2620 high school students(age ranging from 12 years to 18 years) from four high schools of Changsha City using Diagnostic Questionnaire for internet Addiction (YDQ). According to the modified YDQ criteria by Beard, 64 students were diagnosed as internet addiction. Excluding current psychiatric comorbidity, 50 students who were diagnosed as internet Addiction (mean age, 14.8 ± 1.4 years) and 50 normal students in internet usage(mean age, 14.5 ± 1.8 years) were included in a case control study. The two groups were assessed using Barratt Impulsiveness Scale 11 (BIS-11) and behavioral measure of impulsivity (GoStop Impulsivity Paradigm).

Results

Sixty-four students met the modified YDQ criteria by Beard, of whom 14 students suffered from comorbid psychiatric disorders, especially comorbid ADHD. The internet Addiction group had significantly higher scores on the BIS-11 subscales of Attentional key, Motor key, and Total scores than the control group (P < 0.05). The internet Addiction group scored higher than the control group on the failure to inhibit responses of GoStop Impulsivity Paradigm (P < 0.05). There was a significant positive correlation between YDQ scores and BIS-11subscales and the number of failure to inhibit responses of GoStop Impulsivity Paradigm.

Conclusion

This study suggests that adolescents with internet addiction exhibit more impulsivity than controls and have various comorbid psychiatric disorders, which could be associated with the psychopathology of internet addiction.
SNAP‐23 is not essential for constitutive exocytosis in HeLa cells
Authors: Okayama Miki , Arakawa Toshiya , Mizoguchi Itaru , Tajima Yoshifumi , Takuma Taishin
Published: September 2007

We applied the small interfering RNA (siRNA) technique and over‐expression of a dominant‐negative mutant to evaluate the role of SNAP‐23, a non‐neuronal isoform of SNAP‐25, in constitutive exocytosis from HeLa cells. Although the protein level of SNAP‐23 was reduced to less than 10% of the control value by siRNA directed against SNAP‐23, exocytosis of SEAP (secreted alkaline phosphatase) was normal. Double knockdown of SNAP‐23 and syntaxin‐4 also failed to inhibit the secretion. Furthermore, over‐expression of δC8‐SNAP‐23, a dominant‐negative mutant of SNAP‐23, did not abrogate SEAP secretion. These results suggest that SNAP‐23 is not essential for constitutive exocytosis of SEAP.
Induction of lipid peroxidation and decrease of antioxidant defenses in symptomatic and asymptomatic patients with X‐linked adrenoleukodystrophy
Authors: Deon Marion , Sitta Angela , Barschak Alethea G. , Coelho Daniela M. , Pigatto Maiara , Schmitt Graziela O. , Jardim Laura B. , Giugliani Roberto , Wajner Moacir , Vargas Carmen R.
Published: September 2007

Patients affected by X‐linked adrenoleukodystrophy (X‐ALD) present a progressive brain and peripheral demyelination and adrenal cortex insufficiency, associated with accumulation of the very long chain fatty acids (VLCFA) hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0) in different tissues and biological fluids. X‐ALD is characterized by heterogeneous clinical phenotypes. Seven clinical variants have been described for this genetic disorder, being the childhood cerebral form (CCER), adrenomyeloneuropathy (AMN) and asymptomatic the most common clinical forms. In a previous work, we showed evidence that oxidative stress is involved in the pathophysiology of X‐ALD symptomatic patients. In the present study, we compared oxidative stress parameters, namely thiobarbituric acid reactive substances (TBA‐RS) and total antioxidant status (TAS), in plasma from patients with CCER, AMN and in asymptomatic X‐ALD patients. It was observed that symptomatic and asymptomatic X‐ALD patients presented a significant increase of plasma TBA‐RS measurement, indicating a stimulation of lipid peroxidation. Furthermore, lipid peroxidation was higher in AMN, as compared to CCER and asymptomatic patients. We also observed that the total antioxidant defenses (TAS) were decreased in symptomatic but not in asymptomatic X‐ALD patients. Therefore, it may be presumed that asymptomatic patients seem to be protected against oxidative stress because of their normal antioxidant defenses and that other factors besides oxidative damage may be responsible for the severity of the symptoms in X‐ALD and need to be investigated.
Variation in harvest index of modern spring barley, oat and wheat cultivars adapted to northern growing conditions
Authors: PELTONEN-SAINIO P. , MUURINEN S. , RAJALA A. , JAUHIAINEN L.
Published: September 2007

Increased harvest index (HI) has been one of the principal factors contributing to genetic yield improvements in spring barley (Hordeum vulgareL.), oat (Avena sativaL.) and wheat (Triticum aestivumL.) cultivars. Although high HI demonstrates high-yielding ability when cultivars are compared, it can also indicate challenges to yield formation when comparisons are made across differing growing conditions. The present study was designed to investigate variation in HI among modern cereal cultivars relative to that brought about by a northern environment, to assess whether HI still explains the majority of the differences in grain yield when only modern cereal cultivars are compared, and to monitor key traits contributing to HI. Stability of HI was also investigated with reference to the role of tillers. Twelve experiments (3 years, two locations, two nitrogen fertilizer regimes) were carried out in southern Finland to evaluate 12 two-row spring barley, 10 six-row barley, 10 oat and 11 wheat cultivars. In addition to HI, days to heading and maturity, length of grain filling period, grain yield, test weight and 13 traits characterizing plant stand structure were measured and analysed with principal component analysis (PCA) to detect traits associated with HI and those contributing to stability of HI. Although only modern cereals were studied, differences among cultivars were significant both in mean HI and stability of HI, and HI was associated with short plant stature in all modern cereal species. Also, single grain weight was associated with HI in all species. Differences between, but not within, species in HI were partly attributable to differences in tiller performance. Grain yield was associated closely with HI except in two-row barley. It may be possible to further increase HI of wheat, as it still was relatively low. High HI did, however, not indicate the degree of success in yield determination when environments are compared.
URBAN–RURAL CONTRASTS IN EXPLANATORY MODELS AND TREATMENT-SEEKING BEHAVIOURS FOR STROKE IN TANZANIA
Authors: MSHANA G. , HAMPSHIRE K. , PANTER-BRICK C. , WALKER R. ,   THE TANZANIAN STROKE INCIDENCE PROJECT TEAM
Published: September 2007

Stroke is an emerging problem in sub-Saharan Africa, about which little is known since most research to date has been based on retrospective, hospital-based studies. This anthropological work, designed to complement a large community-based project on stroke incidence, focuses on local understandings and treatment-seeking behaviours in urban (Dar-es-Salaam) and rural (Hai) areas of Tanzania. Semi-structured interviews (n=80) were conducted with 20 stroke patients, 20 relatives of stroke patients, ten traditional healers, and 30 other local residents. In contrast to common expectations, and literature that finds witchcraft beliefs to be most common in rural areas, stroke in urban Dar was widely believed to emanate from supernatural causes (demons and witchcraft), while in rural Hai, explanations drew mostly on ‘natural’ causes (hypertension, fatty foods, stress). These different beliefs and explanatory models fed into treatment-seeking behaviours. The first option in Hai was hospital treatment, while in Dar-es-Salaam, where belief in demons led to hospital avoidance, it was traditional healers. In both sites, multiple treatment options (serially or simultaneously) were the norm. Analysis of patient and carer narratives suggested that causation beliefs outweighed other factors, such as cost and distance, in shaping effective treatment. Three policy implications are drawn. First, as other studies have also shown, it is important to engage with, rather than dismiss, local explanations and interpretations of stroke. Stroke awareness messages need to take into account the geographical and belief systems differences. Developing an understanding of explanatory models that recognizes that local beliefs arise from dynamic processes of social interaction will be critical to designing effective interventions. Second, there is a clear role for multiple healing systems with possibility of cross-reference in the case of a chronic, disabling condition like stroke, since biomedical treatment cannot offer a ‘quick fix’ while traditional healers can help people come to terms with their condition. Third, issues of communication between health services and their patients are particularly critical.
Toxoplasma gondiiinduces changes in intracellular calcium in macrophages
Authors: MASEK K. S. , ZHU P. , FREEDMAN B. D. , HUNTER C. A.
Published: September 2007

Toxoplasma gondiiis an obligate intracellular parasite that interacts with calcium storage organelles and induces calcium-dependent signalling in macrophages. This study was performed to determine whetherToxoplasmainduces changes in intracellular calcium in these cells. Ratiometric imaging of live, Fura-2 loaded macrophages challenged withT. gondiirevealed robust elevations in intracellular calcium. These elevations were late in onset, beginning 15–20 min after addition of parasites and occurred in up to 20% of macrophages in an imaging field. Further characterization of these events revealed that they follow from challenge with liveT. gondii, but not heat-killed parasites or solubleToxoplasmaantigen (STAg). Parasite-induced calcium elevations derived from extracellular sources, and were independent of host recognition factors MyD88 and CCR5. These findings indicate thatToxoplasma gondiialters calcium homeostasis in macrophages and this activity is independent of known pathways involved in the innate recognition of this organism.
Molecular evidence of prevalent dual piroplasma infections in North American raccoons (Procyon lotor)
Authors: BIRKENHEUER A. J. , MARR H. S. , HLADIO N. , ACTON A. E.
Published: September 2007

Based on 18S rRNA sequence analyses 2 distinct genotypes of piroplasms have been described in raccoons. One genotype resides in the Babesia sensu stricto clade and the other in the Babesia microti-like clade. Since these organisms appear morphologically indistinguishable, it is unclear which strain is responsible for the majority of the infections in raccoons. In order to overcome these limitations we performed a molecular survey of raccoons using polymerase chain reaction assays specific for each genotype. We tested blood samples from 41 wild raccoons trapped in eastern North Carolina using PCR assays and found that 95% (39/41) had detectable piroplasm DNA. Ninety percent (37/41) of the samples contained Babesia sensu stricto DNA and 83% (34/41) samples contained Babesia microti-like DNA. DNA from both genotypes was present in 76% (31/41) samples suggesting a very high rate of co-infections. The presence of dual piroplasma infections in carnivores appears to be an uncommon finding. This study highlights the need for molecular assays for the accurate identification of piroplasma. Further studies are indicated to investigate the ability of these parasites to infect domestic animals as well as their zoonotic potential.
The rising impact of mathematical modelling in epidemiology: antibiotic resistance research as a case study
Authors: TEMIME L. , HEJBLUM G. , SETBON M. , VALLERON A. J.
Published: September 2007

Mathematical modelling of infectious diseases has gradually become part of public health decision-making in recent years. However, the developing status of modelling in epidemiology and its relationship with other relevant scientific approaches have never been assessed quantitatively. Herein, using antibiotic resistance as a case study, 60 published models were analysed. Their interactions with other scientific fields are reported and their citation impact evaluated, as well as temporal trends. The yearly number of antibiotic resistance modelling publications increased significantly between 1990 and 2006. This rise cannot be explained by the surge of interest in resistance phenomena alone. Moreover, modelling articles are, on average, among the most frequently cited third of articles from the journal in which they were published. The results of this analysis, which might be applicable to other emerging public health problems, demonstrate the growing interest in mathematical modelling approaches to evaluate antibiotic resistance.
The impact of climate on Japanese encephalitis
Authors: HSU S. M. , YEN A. M. F. , CHEN T. H. H.
Published: September 2007

The aim of this study was to assess the change of seasonal pattern of Japanese encephalitis (JE) cases in the post-vaccination period and to elucidate whether the lagged climate variables (precipitation and temperature) were associated with occurrence of JE after adjustment for seasonal pattern, time trend, geographic areas, pig density, vaccination coverage rate for humans, and time dependence of time-series numbers of JE cases. A total of 287 confirmed JE cases between 1991 and 2005 were collected, together with monthly data on socio-ecological archival data including climate, pig density and vaccination. A time-series generalized autoregressive Poisson regression model was used to achieve the objectives. The rate of JE increased from 1998 onwards. The seasonal pattern on occurrence of JE cases clustered between May and August during the period from 1991 to 2005 in Taiwan. In each geographic area, monitoring temperature and precipitation, two possible proxy variables for mosquito density, in conjunction with seasonal factors and pig density is of assistance in forecasting JE epidemics.
Generalised and abdominal obesity and risk of diabetes, hypertension and hypertension–diabetes co-morbidity in England
Authors: Hirani Vasant , Zaninotto Paola , Primatesta Paola
Published: September 2007

Objectives

To look at trends in generalised (body mass index (BMI) ≥30 kg m–2) and abdominal (waist circumference (WC) >102 cm in men, >88 cm in women) obesity among adults between 1993 and 2003, and to evaluate their association with diabetes, hypertension and hypertension–diabetes co-morbidity (HDC) in England.

Design

Analyses of nationally representative cross-sectional population surveys, the Health Survey for England (HSE).

Subjects

Non-institutionalised men and women aged ≥35 years.

Measurements

Interviewer-administered questionnaire (sociodemographic information, risk factors, doctor-diagnosed diabetes), measurements of height and weight to calculate BMI. WC and blood pressure measurements were taken by trained nurses.

Results

Generalised obesity increased among men from 15.8% in 1993 to 26.3% in 2003, and among women from 19.3% to 25.8%. Abdominal obesity also increased in both sexes (men: 26.2% in 1993 to 39.0% in 2003; women: 32.4% to 47.0%). In 1994, 1998 and 2003, generalised and abdominal obesity were independently associated with risk of hypertension, diabetes and HDC. The odds of diabetes associated with generalised obesity in 1994, 1998 and 2003 were 1.62, 2.26 and 2.62, respectively, in women and 1.24, 1.82 and 2.10, respectively, in men. Similar differences were observed for hypertension and HDC. Men and women with abdominal obesity also showed a higher risk for diabetes, hypertension and HDC than those with a normal WC.

Conclusions

If current trends in obesity continue then the risk of related morbidities may also increase. This will impact on cardiovascular disease morbidity and mortality, with cost implications for the health service. Therefore there is an urgent need to control the epidemic of obesity.