bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced synaptic activity precedes synaptic stripping in vagal motoneurons after axotomy
Authors: Yamada Jun , Hayashi Yoshinori , Jinno Shozo , Wu Zhou , Inoue Kazuhide , Kohsaka Shinichi , Nakanishi Hiroshi 
Published: May 2008

AbstractActivated microglia, which spread on the motor neurons following nerve injury, engage in the displacement of detached afferent synaptic boutons from the surface of regenerating motor neurons. This phenomenon is known as “synaptic stripping.” The present study attempted to examine whether changes in the synaptic inputs after motor nerve injury correlated with the microglial attachment to the dorsal motor neurons of the vagus (DMV). DMV neurons in Wistar rats could survive after nerve injury, whereas most of injured DMV neurons in the C57BL/6 mice died. At 2 days after nerve injury, a significant decrease was observed in the frequencies of both spontaneous and miniature EPSCs and IPSCs recorded from DMV neurons in the slice preparation but not from the mechanically dissociated neurons in the Wistar rats. At this stage, no direct apposition of microglia on the injured neurons was observed. High‐K+ stimulation restored their frequencies to control levels. Furthermore, PPADS and DPCPX, antagonists of P2 and adenosine receptors, respectively, also stimulated the recovery of their frequencies. In contrast, no significant change was detected in the spontaneous EPSCs frequency recorded from the severely injured DMV neurons in the slice preparation of the C57BL/6 mice. These observations strongly suggest that presynaptic inhibition through glia‐derived ATP and adenosine, thus precedes synaptic stripping in regenerating DMV neurons following nerve injury. © 2008 Wiley‐Liss, Inc.
Hypoxia selects for androgen independent LNCaP cells with a more malignant geno‐ and phenotype
Authors: Butterworth Karl T. , McCarthy Helen O. , Devlin Andrea , Ming Louise , Robson Tracy , McKeown Stephanie R. , Worthington Jenny 
Published: May 2008

AbstractHypoxia confers resistance to common cancer therapies, however, it has also has been shown to result in genetic alterations which may allow a survival advantage and increase the tumorigenic properties of cancer cells. Additionally, it may exert a selection pressure, allowing expansion of tumor cells with a more aggressive phenotype. To further assess the role of hypoxia in malignant progression in prostate cancer we exposed human androgen dependent prostate cancer cells (LNCaP) to cycles of chronic hypoxia and isolated a subline, LNCaP‐H1. This article describes the partial characterization of this cell line. The LNCaP‐H1 subline showed altered growth characteristics and exhibited androgen independent growth both in vitro and in vivo. Furthermore, these cells were resistant to mitochondrial‐mediated apoptosis, probably since the endogenous levels of Bax was lower and Bcl‐2 higher than in the parental LNCaP cells. Microarray analysis revealed that a complex array of pathways had differential gene expression between the 2 cell lines, with LNCaP‐H1 cells exhibiting a genetic profile which suggests that they may be more likely metastasize to distant organs, especially bone. This was supported by an in vitro invasion assay, and an in vivo metastasis study. This study shows that hypoxia can select for androgen independent prostate cancer cells which have a survival advantage and are more likely to invade and metastasize. © 2008 Wiley‐Liss, Inc.
P53 mutations in stromal fibroblasts sensitize tumors against chemotherapy
Authors: Lafkas Daniel , Trimis George , Papavassiliou Athanasios G. , Kiaris Hippokratis 
Published: May 2008

AbstractThe efficacy of chemotherapy is usually viewed as the outcome of cancer‐cell‐autonomous processes while the contribution of stroma is being overseen. Here we show that p53 mutations in stromal fibroblasts, a genetic lesion that is detectable in primary breast, prostate and probably other cancers, while they accelerate tumorigenesis they also sensitize tumours against conventional chemotherapy by doxorubicin and cis‐platinum. The mechanism by which p53 of stromal fibroblasts affects the response of a tumour against chemotherapy is likely to involve the induction of senescence in the fibroblasts which in turns results in the production of growth factors acting onto the cancer cells by paracrine mechanisms. Our findings identify stromal fibroblasts as important modulators of the efficacy of anticancer therapy. © 2008 Wiley‐Liss, Inc.
Vitamin E and cancer: An insight into the anticancer activities of vitamin E isomers and analogs
Authors: Constantinou Constantina , Papas Andreas , Constantinou Andreas I. 
Published: May 2008

AbstractCurrent observations in the literature suggest that vitamin E may be a suitable candidate for the adjuvant treatment of cancer. Even though historically most research focused on α‐tocopherol, more recent evidence suggests that the other isomers of vitamin E (β‐, γ‐ and δ‐tocopherols and α‐, β‐, γ‐ and δ‐tocotrienols) differ in their proapoptotic potencies. The main focus of this communication is the current understanding of the molecular mechanisms regulated by vitamin E isomers and their analogs during the induction of apoptosis. This review highlights that the mitochondria are the major target for the induction of apoptosis by vitamin E isomers and analogs and that the various signaling pathways regulated by these agents are likely to contribute towards maximizing the intrinsic pathway of apoptosis triggered initially by the mitochondria. Overall, the presentation of recent studies from the literature in this communication allows the drawing of the following important conclusions: (i) no direct link exists between the antioxidant activity of each isomer/derivative and proapoptotic potency, (ii) tocotrienols are more effective proapoptotic agents than tocopherols, (iii) synthetic modifications of the naturally occurring compounds may improve their apoptotic potency and (iv) vitamin E isomers and derivatives regulate caspase‐independent pathways of apoptosis. The latter combined with the evidence presented in this review regarding the additive or synergistic anticarcinogenic effects obtained when vitamin E analogs are used in combination with other cancer chemotherapeutic agents, supports further research to design the most promising vitamin E derivatives and clinically test them in adjuvant chemotherapeutic treatments. © 2008 Wiley‐Liss, Inc.
Fabrication and characterization of functionally graded nano‐micro porous titanium surface by anodizing
Authors: Kim Hyun‐Seung , Yang Yunzhi , Koh Jeong‐Tae , Lee Kyung‐Ku , Lee Doh‐Jae , Lee Kwang‐Min , Park Sang‐Won 
Published: May 2008

AbstractThe purpose of this study was to fabricate and characterize nanotubular structure on machined titanium (MA) and resorbable blast media (RBM) treated titanium by anodizing. The anodized MA and RBM were characterized with scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, energy disperse spectra, X‐ray photoelectron spectra, and nano‐indentation and scratch test. Highly ordered nanotubular layers of individually 100 nm in diameter and 500 nm in length approximately were formed regardless of the substrates. The nanotubular layers consisted mainly of amorphous TiO2 with trace fluorine. The nanotubular surfaces on both the substrates significantly reduced water contact angles and elastic modulus compared with those prior to anodizing. The anodizing treatment significantly increased the surface roughness of the smooth MA, but significantly decreased the surface roughness of the roughened RBM. The critical delamination forces of the nanotubular layer were not obtained due to the limitation of surface roughness. The anodized RBM consisted of a nano‐micro porous graded structure, or a nanotubular amorphous fluoride containing TiO2 layer on top of micro‐roughened titanium surface, which is expected to significantly improve the surface area that can be used to deliver drugs and growth factors and alleviate the interfacial elastic modulus mismatch as to enhance osseointegration when compared with conventional dental and orthopedic implant devices with smooth or acid etched surface. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Modification of the CHARMM force field for DMPC lipid bilayer
Authors: Högberg Carl‐Johan , Nikitin Alexei M. , Lyubartsev Alexander P. 
Published: May 2008

AbstractThe CHARMM force field for DMPC lipids was modified in order to improve agreement with experiment for a number of important properties of hydrated lipid bilayer. The modification consists in introduction of a scaling factor 0.83 for 1–4 electrostatic interactions (between atoms separated by three covalent bonds), which provides correct transgauche ratio in the alkane tails, and recalculation of the headgroup charges on the basis of HF/6‐311(d,p) ab‐initio computations. Both rigid TIP3P and flexible SPC water models were used with the new lipid model, showing similar results. The new model in a 75 ns simulation has shown a correct value of the area per lipid at zero surface tension, as well as good agreement with the experiment for the electron density, structure factor, and order parameters, including those in the headgroup part of lipids. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008
A new upper bound for the bipartite Ramsey problem
Authors: Conlon David 
Published: May 2008

AbstractWe consider the following question: how large does n have to be to guarantee that in any two‐coloring of the edges of the complete graph Kn,n there is a monochromatic Kk,k? In the late 1970s, Irving showed that it was sufficient, for k large, that n ≥ 2k − 1 (k − 1) − 1. Here we improve upon this bound, showing that it is sufficient to take

where the log is taken to the base 2. © 2008 Wiley Periodicals, Inc. J Graph Theory 58: 351–356, 2008
Inequalities for the first‐fit chromatic number
Authors: Füredi Zoltán , Gyárfás András , Sárközy Gábor N. , Selkow Stanley 
Published: May 2008

AbstractThe First‐Fit (or Grundy) chromatic number of G, written as χFF(G), is defined as the maximum number of classes in an ordered partition of V(G) into independent sets so that each vertex has a neighbor in each set earlier than its own. The well‐known Nordhaus‐‐Gaddum inequality states that the sum of the ordinary chromatic numbers of an n‐vertex graph and its complement is at most n + 1. Zaker suggested finding the analogous inequality for the First‐Fit chromatic number. We show for n ≥ 10 that ⌊(5n + 2)/4⌋ is an upper bound, and this is sharp. We extend the problem for multicolorings as well and prove asymptotic results for infinitely many cases. We also show that the smallest order of C4‐free bipartite graphs with χFF(G) = k is asymptotically 2k2 (the upper bound answers a problem of Zaker [9]). © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 75–88, 2008
Identification of degradation mechanisms in coatings for supercritical steam applications
Authors: Durham R. N. , Singheiser L. , Quadakkers W. J. 
Published: May 2008

AbstractThe development and qualification of coatings for materials used in modern steam power plants stems from the increased demand for higher efficiency, and hence higher operating temperatures. Within the EU funded project ‘SUPERCOAT’, several coatings, both overlay and diffusion type, were investigated. Seven different coatings are presented in this work. They included two commercially available HVOF coatings (Ni–20Cr and Ni–50Cr), an aluminium‐based slurry coating (IPCOTE), together with two further variations of this slurry coating containing sputter‐coated inter‐layers. An overlay slurry coating consisting of silica particles embedded in a matrix of alumina and chromia was also examined. The final coating to be investigated was a pack‐aluminised sample of P92.All the coating systems examined showed superior oxidation resistance compared to the 9%Cr steel substrate (P91 or P92) in extended exposures to a steam environment at 650 °C. However, in service component lifetime will be limited by degradation of the coating, therefore it is essential that the mechanisms controlling this behaviour are understood. This paper reviews several degradation mechanisms that have been observed during long‐term exposure of these coatings. The mechanisms that have been observed include depletion of active alloying elements, diffusion of aluminium into the substrate from the coating, formation of Kirkendall porosity and mechanical failure of the coatings. Examples of each of these mechanisms will be presented. Possible processing routes to avoid these degradation mechanisms will also be discussed.
Influence of Molecular Structure and Stereochemistry of the 1,4‐Cyclohexylene Ring on Thermal and Mechanical Behavior of Poly(butylene 1,4‐cyclohexanedicarboxylate)
Authors: Berti Corrado , Celli Annamaria , Marchese Paola , Marianucci Elisabetta , Barbiroli Giancarlo , Di Credico Francesco 
Published: May 2008

AbstractPoly(butylene 1,4‐cyclohexanedicarboxylate), an aliphatic polyester with favorable properties, such as resistance to weather and potential biodegradability, has been synthesized with different cis/trans ratio of the 1,4‐cyclohexylene ring. The samples show high degradation temperatures, independent of the stereochemistry of the aliphatic ring. Instead, glass transition temperature, crystallization and melting behavior are strongly influenced by the cis/trans ratio. The trans isomer, more rigid and symmetric than the cis, favors higher transition temperatures and crystallizability. The DMTA spectra present two secondary relaxations, attributed to the (CH2) unit and aliphatic ring motions, which can be beneficial for improving impact resistance properties. The physical properties are compared with those of PBT and PCCD.magnified image
Prevalence of cholinesterase inhibitors in subjects with dementia in Europe
Authors: Pariente Antoine , Helmer Catherine , Merliere Yvon , Moore Nicholas , Fourrier‐Réglat Annie , Dartigues Jean‐Francois 
Published: May 2008

AbstractPurposeTo evaluate the prevalence of cholinesterase inhibitor (ChI) treatment in subjects with dementia in European countries.MethodsWe studied the prevalence of treatment in subjects with dementia among European countries in 2004 (Belgium, France, Germany, Italy, the Netherlands, Poland, Portugal, Spain and the United Kingdom) by using estimates of prevalence of dementia and of ChI treatments according to sales and reimbursement data.ResultsIn 2004, estimated prevalence of ChI use among subjects with dementia ranged from 3.0% in the Netherlands to 20.3% in France. It was 17.5% in Spain, 6.7% in the UK and 5.9% in Italy. Donepezil was used by more than 60% of patients using a single ChI and represented almost 50% of reimbursements for patients that had used at least two different ChIs during the year. Galantamine and rivastigmine were respectively used by 22 and 18% of subjects using a single drug and 27 and 23% of reimbursements for patients that had used at least two different ChIs. Nevertheless, different patterns of use were found for individual countries.ConclusionsPrevalence of treatment by ChIs among subjects with dementia remains weak and varies greatly across Europe. Differences in reimbursement rates and health policies could partly explain these variations, as ChIs could have failed to convince health authorities because the outcomes considered for trials are not used by clinicians in their everyday practice. If donepezil was highly predominant across countries, variations in rivastigmine and galantamine importance could reflect local market specificities. Copyright © 2008 John Wiley & Sons, Ltd.
Hydrolysis of aliphatic naphthalene diimides: effect of charge placement in the side chains
Authors: Kim Michelle B. , Dixon Dabney W. 
Published: May 2008

AbstractWater‐soluble naphthalene diimides (NDIs) have found uses in a wide variety of applications including as electron acceptors in electron transfer reactions and as molecules that undergo spontaneous organization in aqueous solution. Many studies have looked at their interaction with nucleic acids including work with DNA duplexes, triplexes, quadruplexes, hairpins, and DNA–RNA heteroduplexes. In many of these interactions the NDIs serve as threading intercalators. Herein we describe the reversible hydroxide‐catalyzed hydrolysis of NDIs bearing aliphatic side chains, with ring opening first to the monoimide and then to the diamide. Examples with N‐methylpyrrolidinium groups placed two (1) and three (5) atoms from the central core were studied. The Ka values for the first and second hydrolyses for 1 were 2.5 ± 0.2 × 105 and 2.0 ± 0.1 × 102 M−1, respectively; for 5 they were 1.4 ± 0.1 × 105 and 44 ± 2 M−1, respectively. NDI 1 hydrolyzed 6.8 times faster than 5. The rates for the first and second ring opening of 1 in 100 mM hydroxide measured by stopped‐flow were 17.0 ± 0.2 and 0.53 ± 0.01 s−1, respectively. Capillary electrophoresis in borate buffer showed separation of the diimide and monoimide with the former eluting first. Nuclear magnetic resonance (NMR) showed both the syn and anti isomers of the diamide species. Overall, the rate of hydrolysis of the NDI is increased when the cationic charge is moved closer to the NDI core. Copyright © 2008 John Wiley & Sons, Ltd.
Kinetics study of a Diels‐Alder reaction in mixtures of an ionic liquid with molecular solvents
Authors: Harifi‐Mood Ali Reza , Habibi‐Yangjeh Aziz , Gholami Mohammad Reza 
Published: May 2008

AbstractThe second‐order rate constants for cycloaddition reaction of cyclopentadiene with naphthoquinone were determined spectrophotometrically in various compositions of 1‐(1‐butyl)‐3‐methylimidazolium terafluoroborate ([bmim]BF4) with water and methanol at 25 °C. Rate constants of the reaction in pure solvents are in the order of water > [bmim]BF4 > methanol. Rate constants of the reaction decrease sharply with mole fraction of the ionic liquid in aqueous solutions and increase slightly to a maximum in alcoholic mixtures. Multi‐parameter correlation of logk2 versus solute–solvent interaction parameters demonstrated that solvophobicity parameter (Sp), hydrogen‐bond donor acidity (α) and hydrogen‐bond acceptor basicity (β) of media are the main factors influencing the reaction rate constant. The proposed three‐parameter model shows that the reaction rate constant increases with Sp, α and β parameters. Copyright © 2008 John Wiley & Sons, Ltd.
Locally Resolving Measurements of PSD, Particle Concentration and Particle Velocity by Means of TFS with Dual Beams
Authors: Guo Xiaoai , Riebel Ulrich 
Published: May 2008

AbstractTransmission fluctuation spectrometry with spatial correlation (TFS‐SC) is based on transmitting two beams of radiation through a flowing suspension, whereby the distance of the beam centers is varied. Thus, the spatial correlation of the transmission fluctuations of the two beams is determined as a function of the beam distance.By numerical modeling, the transition functions of the correlation are found as a function of beam distance, beam diameters, particle diameter and beam intersection angle.Experimentally determined spatial correlation spectra can be inverted to obtain the particle concentration and particle size distribution by using the theoretical transition functions for mono‐sized particles. In addition, time correlations can be used to extract information on particle velocity. Some experimental results obtained by TFS‐SC are presented and discussed. This method appears promising for application in the local resolving of measurements of PSD, particle concentration and particle velocity in two‐phase flows, both in the laboratory and in process control.
Nanocrystallites obtained through the pyrosol method
Authors: Dinu E. , Andronescu E. , Ghitulica C. D. , Siebert E. , Djurado E. , Dessemond L. 
Published: May 2008

AbstractThe decrease of particles size from micrometric to the nanometric scale is allowing the development of new materials, with dramatically improved properties. The pyrolysis of aerosols is a very interesting method of production for reactive nanopowders. In this study, the influence of various synthesis parameters on the crystallinity and the composition of calcium phosphate powders were investigated. Firstly, the influence of the chemical nature of the calcium precursor was studied, by using two types of water‐soluble calcium salts: CaCl2·2H2O and Ca(NO3)2. Secondly, the effect of the pyrolysis temperature, in the 600–1000 °C interval was studied. Whatever the temperature of pyrolysis of the aerosol, the apatite structure is recognizable, if the precursor used for the calcium oxide is calcium chloride. If the powders are elaborated starting from calcium nitrate, the only phase identified is β‐calcium phosphate. The synthesized powders have spherical morphology, are highly porous and dimensionally in the nanometric range. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prerequisites of nanocavities for single artificial atom laser
Authors: Nomura M. , Iwamoto S. , Arakawa Y. 
Published: May 2008

AbstractPrerequisites of nanocavities for single quantum dot laser have been theoretically studied by a fully quantum‐mechanical treatment. Numerical simulations are performed by solving master equations for single four‐level electronic system and single cavity electric field mode. Experimentally obtained parameters are used in the simulations to predict prerequisites of the cavity quality factor Q and allowable range of the relative position control of the cavity and a target quantum dot. In the case of a photonic crystal defect nanocavity with a modal volume of 0.04 μm3, the required Q for lasing is 65,000 assuming the atom‐field coupling strength g = 40 GHz. The dephasing effect is also taken into account in the simulation. The results indicate that the dephasing effect can be negligible when the transverse relaxation time is longer than ∼ 100 ps. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selective growth of InP on localized areas of silicon (100) substrate by molecular beam epitaxy
Authors: Araki K. , Seo J. U. , Hasegawa S. , Asahi H. 
Published: May 2008

AbstractTo use III‐V compound semiconductors as channel materials in the future advanced MISFETs with high performance, it is important to acheive the growth of III‐V‐on‐Insulator structures on Si substrates. As a first step to accomplish this, we propose the selective formation of InP only on localized areas of Si (100) substrate by molecular beam epitaxy (MBE). It was found that InP was selectively grown only on bare Si window areas, while not grown on native silicon oxide areas at elevated substrtate temperatures (500°C). It was also found that by decreasing the window size (0.7×0.7 μm2) only single grain of InP was grown on each bare Si window area. This indicates that the selective MBE growth of InP on Si substrate is possible. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interplay of impurity segregation and lattice mismatch in molecular beam epitaxy of III′–III″–V compounds plus dopant: application to the InGaAs:Sn nanoheterolayer growth
Authors: Chikalova‐Luzina O. 
Published: May 2008

AbstractA thermodynamic model for molecular beam epitaxy of quaternary solid alloys III′–III″–V plus dopant is developed on a practical example of In1x Gax As:Sn/GaAs heterolayer growth. In the frame of the model, the interplay of surface segregation and strain during epitaxy is analyzed. It is shown Sn atoms, being segregated during the growth in the In–stabilized conditions, act as an efficient surfactant, and Sn doping may be used to improve the surface morphology of strained nanoheterolayers. It is found that high doping level and the low growth temperatures are favourable for achieving a smooth morphology. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)