bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation, characterization, and effect of fluorescent pseudomonads on micropropagated sugarcane
Authors: Mehnaz Samina , Weselowski Brian , Aftab Faheem , Zahid Sadaf , Lazarovits George , Iqbal Javed
Published: November 2009

In this study, we report on the isolation, identification, and characterization of seven fluorescent pseudomonads isolated from the roots, shoots, and rhizosphere soil of sugarcane and their impacts on the growth of sugarcane plantlets. 16S rRNA gene sequence of five isolates showed close homology with Pseudomonas putida , one with Pseudomonas graminis , and one with Pseudomonas fluorescens . Physiological and biochemical characterizations were determined using API50CH and QTS24 identification kits. The isolates were also subjected to tests for various known growth promoting properties including production of indole acetic acid, the ability to fix nitrogen via the presence of the nifH gene, and ability to solubilize phosphate. Biological control potential was determined from agar diffusion assays of HCN production and production of antifungal compounds against local isolates of Colletotrichum falcatum (that induces red-rot disease of sugarcane). Direct plant growth promoting effects were tested on sugarcane plantlets in tissue culture under gnotobiotic conditions. All seven isolates provided significant increases in fresh and dry masses but only five strains increased shoot height.
Identification of secreted and surface proteins from Enterococcus faecalis
Authors: Benachour Abdellah , Morin Thierry , Hébert Laurent , Budin-Verneuil Aurélie , Le Jeune André , Auffray Yanick , Pichereau Vianney
Published: November 2009

Secreted and surface proteins of bacteria are key molecules that interface the cell with the environment. Some of them, corresponding to virulence factors, have already been described for Enterococcus faecalis , the predominant species involved in enterococcal nosocomial infections. In a global proteomic approach, the identification of the most abundant secreted and surface-associated proteins of E. faecalis JH2-2 strain was carried out. These proteins were separated by gel electrophoresis or directly subjected to in vivo trypsinolysis and then analyzed by liquid chromatography – electrospray ion trap tandem mass spectrometry. Putative functions were assigned by homology to the translated genomic database of E. faecalis. A total of 44 proteins were identified, eight secreted proteins from the supernatant culture and 38 cell surface proteins from two-dimensional gel electrophoresis and in vivo trypsinolysis among which two are common to the two groups. Their sequences analysis revealed that 35 of the 44 proteins harbour characteristic features (signal peptide or transmembrane domains) consistent with an extracellular localization. This study may be considered as an important step to encourage proteomic-based investigations of E. faecalis cell surface associated proteins that could lead to the discovery of virulence factors and to the development of new therapeutic tools.
Plasmid transfer systems in the rhizobia
Authors: Ding Hao , Hynes Michael F.
Published: November 2009

Rhizobia are agriculturally important bacteria that can form nitrogen-fixing nodules on the roots of leguminous plants. Agricultural application of rhizobial inoculants can play an important role in increasing leguminous crop yields. In temperate rhizobia, genes involved in nodulation and nitrogen fixation are usually located on one or more large plasmids (pSyms) or on symbiotic islands. In addition, other large plasmids of rhizobia carry genes that are beneficial for survival and competition of rhizobia in the rhizosphere. Conjugative transfer of these large plasmids thus plays an important role in the evolution of rhizobia. Therefore, understanding the mechanism of conjugative transfer of large rhizobial plasmids provides foundations for maintaining, monitoring, and predicting the behaviour of these plasmids during field release events. In this minireview, we summarize two types of known rhizobial conjugative plasmids, including quorum sensing regulated plasmids and RctA-repressed plasmids. We provide evidence for the existence of a third type of conjugative plasmid, including pRleVF39c in Rhizobium leguminosarum bv. viciae strain VF39SM, and we provide a comparison of the different types of conjugation genes found in members of the rhizobia that have had their genomes sequenced so far.
Relationships between bacterial diversity, microbial biomass, and litter quality in soils under different plant covers in northern Rio de Janeiro State, Brazil
Authors: Ndaw S. M. , Gama-Rodrigues A. C. , Gama-Rodrigues E. F. , Sales K. R.N. , Rosado A. S.
Published: November 2009

Microbial populations are primarily responsible for the decomposition of organic residues, the nutrients cycle, and the flow of energy inside of soil. The present study was undertaken to link soil microbiological and soil biochemical parameters with soil- and litter-quality conditions in the surface layer from 5 sites differing in plant cover, in stand age, and in land-use history. The aim was to see how strongly these differences affect the soil microbial attributes and to identify how microbiological processes and structures can be influenced by soil and litter quality. Soil and litter samples were collected from 5 sites according to different land use: preserved forest, nonpreserved forest, secondary forest, pasture, and eucalyptus plantation. Soil and litter microbial biomass and activity were analysed and DNA was extracted from soil. The DNA concentrations and soil microbial C and N correlated positively and significantly, suggesting that these are decisive nutrients for microbial growth and time required for microbial biomass renewal. The litter microbial biomass represented a source of C and N higher than soil microbial biomass and can be an important layer to contribute to tropical soil with low C and N availability. The litter quality influenced the litter and soil microbial biomass and activity and the soil bacterial diversity. The chemical and nutritional quality of the litter influenced the structure and microbial community composition in the eucalyptus plantation.
Identification of antifungal antibiotics ofBacillusspecies isolated from different microhabitats using polymerase chain reaction and MALDI-TOF mass spectrometry
Authors: Athukorala Sarangi N.P. , Fernando W. G. Dilantha , Rashid Khalid. Y.
Published: November 2009

Although many Bacillus species are known to be good antibiotic producers capable of acting as biocontrol agents, the underlying antimicrobial mechanisms are often poorly understood. In this study, 21 Bacillus strains, demonstrating over 50% mycelial inhibition against Sclerotinia sclerotiorum as well as significant control in plant assays, were examined for the presence of antibiotic biosynthetic genes. Primers specific for bacillomycin D, iturin A, surfactin, mycosubtilin, fengycin, and zwittermicin A were used to amplify biosynthetic genes from these bacteria using PCR. The majority of strains harbored surfactin (21/21) and iturin A (20/21) biosynthetic genes. Three strains ( Bacillus subtilis 3057, Bacillus amyloliquefaciens BS6, and Bacillus mycoides 4079) were positive for bacillomycin D, whereas 4 strains (B. subtilis H-08-02, B. subtilis 3057, B. amyloliquefaciens BS6, and B. mycoides 4079) showed the presence of the fengycin biosynthetic gene. The zwittermicin A gene was detected in B. mycoides S, Bacillus thuringiensis BS8, and B. amyloliquefaciens BS6. Sequence analysis of purified PCR products revealed homology with corresponding genes from other Bacillus sp. in the GenBank database. Production of particular antibiotics in strains BS6, H-08-02, 3057, and 4079 was confirmed through matrix-assisted laser desorption ionization – time of flight – mass spectroscopy (MALDI-TOF-MS). This study revealed the equivalent capability of different Bacillus strains from various microhabitats to produce the above-mentioned antibiotics and highlights the possibility of using some strains as potential biocontrol agents under different microhabitats distant from their original habitat. Furthermore, it will enable researchers to develop rational strategies for the application of the antagonists and their metabolites within an agroecosystem. To the best of our knowledge, this is the first report of a B. mycoides strain that carries biosynthetic genes and produces fengycin and surfactin.
Contribution of cysteine residue to the properties of Listeria monocytogenes listeriolysin O
Authors: Stachowiak Radosław , Wiśniewski Jarosław , Osińska Olga , Bielecki Jacek
Published: November 2009

Listeriolysin (LLO) is the key virulence factor critical for Listeria monocytogenes pathogenesis. Listerial cytolysin belongs to the family of cholesterol-dependent cytolysins (CDCs), a group of pore-forming toxins produced by related gram-positive bacteria. Most CDCs contain a cysteine residue in the conserved undecapeptide — a sequence that is highly preserved among this group of proteins. Substitutions of cysteine do not always lead to loss of hemolytic activity, questioning the purpose of such strong conservation of this amino acid in the sequence of CDC. The properties of 3 L. monocytogenes strains, a wild type and 2 mutants expressing modified LLO within the cysteine residue, were analyzed in this work. The first of these mutants producing a toxin with cysteine to alanine substitution showed similar features to the wild type except that a thiol-reducing agent was not necessary for hemolytic activity. Another strain secreting LLO containing serine instead of cysteine exhibited strikingly different properties than the wild type. Modified toxin is independent of the reducing reagents, less stable, and shows accelerated kinetics of cytolysis in comparison with the unchanged protein. However, both mutant strains are less invasive in the cell culture model showing the important role of cysteine in L. monocytogenes virulence.
Responses of 2 epiphytic yeasts to foliar infection by Rhizoctonia solani or mechanical wounding on the phylloplane of tall fescue
Authors: Nix Shannon , Burpee Leon L. , Buck James W.
Published: November 2009

A growth-chamber experiment was conducted to determine how foliar disease or wounding affects the ability of 2 phylloplane yeasts ( Rhodotorula glutinis and Cryptococcus laurentii ) to colonize leaves of tall fescue ( Festuca arundinacea ). Yeasts were applied separately and together onto healthy leaves, leaves infected with Rhizoctonia solani (diseased), and mechanically bruised (wounded) leaves. In all 3 trials, the leaf disturbance treatment significantly affected the abundance of yeast on the phylloplane of tall fescue. Yeast abundance on the diseased or wounded leaves was significantly greater than on the nontreated, healthy leaves. In 2 of the 3 trials, the yeast species applied also had a significant affect on yeast abundance. Typically, R. glutinis was significantly more abundant than C. laurentii when applied individually, but not significantly greater than the total yeast colony-forming units of the co-inoculated treatment. When the 2 yeasts were co-inoculated onto the leaves, R. glutinis comprised 89.7%, 75.4%, and 67.6% of the recovered yeast colony-forming units on healthy, diseased, and wounded leaves, respectfully. Our data suggest that these 2 species of yeasts will differentially colonize compromised leaf tissue with disease or wounds favoring populations of R. glutinis over C. laurentii.
Contribution of ClpE to virulence ofStreptococcus pneumoniae
Authors: Zhang Qun , Xu Song-Xiao , Wang Hong , Xu Wen-Chun , Zhang Xue-Mei , Wu Kai-Feng , Liu Lan , Yin Yi-Bing
Published: November 2009

The ATP-dependent caseinolytic proteases (Clp) play a fundamental role in stress tolerance and virulence in many pathogenic bacteria. Although ClpE of Streptococcus pneumoniae is required for growth at high temperatures, little is known about the role of ClpE in pathogenesis. In this study, we observed that the virulence of the clpE mutant of S. pneumoniae strain D39 was strongly reduced in a mouse intraperitoneal infection model. The clpE mutant also showed substantially reduced adherence to the human lung epithelial carcinoma A549 cell line and human umbilical-vein-derived endothelial cells. The underlying mechanism of virulence attenuation induced by the mutation of clpE was further investigated with real-time RT–PCR and 2-dimensional protein gel analysis. The results indicate that ClpE affects pneumococcal pathogenesis by modulating the expression of some important virulence determinants and metabolism-related factors in S. pneumoniae.
High molecular weight FGF-2 promotes postconditioning-like cardioprotection linked to activation of the protein kinase C isoforms Akt and p70 S6 kinaseThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba.
Authors: Jiang Zhi-Sheng , Wen Ge-Bo , Tang Zhi-Han , Srisakuldee Wattamon , Fandrich Robert R. , Kardami Elissavet
Published: November 2009

Fibroblast growth factor 2 (FGF-2) is a multifunctional protein translated as high and low molecular weight isoforms (hi- and lo-FGF-2, respectively). Although the postconditioning cardioprotective effect of lo-FGF-2 (18 kDa) has been documented, hi-FGF-2 is less well studied. We used an isolated perfused rat heart model of ischemia–reperfusion to study the effects of postischemic (during reperfusion) administration of hi-FGF-2 on recovery of contractile function and tissue salvage, as indicated by decreased cytosolic cytochrome c levels. Compared with the vehicle-treated group, hi-FGF-2-treated hearts had significantly improved recovery of systolic pressure, developed pressure, rates of contraction and relaxation, and coronary flow, as well as decreased relative levels of cytosolic cytochrome c. The effects of hi-FGF-2 on functional recovery and cytosolic cytochrome c were indistinguishable from those induced by lo-FGF-2. Both hi- and lo-FGF-2 upregulated relative levels of phosphorylated (activated) Akt and p70 S6 kinase, and they both promoted translocation of α, ε, and ζ isoforms of protein kinase C (PKC) to the particulate fraction of reperfused hearts. The magnitude of the effect on PKCζ and p70 S6 kinases, however, was significantly more potent in the hi-FGF-2 than in the lo-FGF-2 group. We conclude that acute postischemic cardioprotection by hi- or lo-FGF-2 is isoform nonspecific and likely to be mediated by PKC and Akt. Nevertheless, isoform-specific functions are suggested by the augmented sensitivity of p70 S6 and PKCζ to hi-FGF-2.
N-methyl-d-aspartate-evoked adenosine and inosine release from neurons requires extracellular calciumThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba.
Authors: Zamzow Christina R. , Bose Ratna , Parkinson Fiona E.
Published: November 2009

The nucleoside adenosine (ADO) is a neuromodulator in brain. ADO and its metabolite inosine (INO) have been shown to increase cell viability in stroke models. During ischemia, extracellular levels of both ADO and INO are increased. In this study, we treated rat cortical neurons with N-methyl-d-aspartate (NMDA) to initiate excitotoxicity and then investigated the mechanisms of ADO and INO release. NMDA induced a significant increase in ADO and INO production. The effect of NMDA receptor antagonists on NMDA-evoked ADO and INO release was examined. MK-801 (1 µmol/L), a potent antagonist that lacks receptor subunit selectivity, completely blocked evoked release of both ADO and INO. Memantine (10 µmol/L), a lower affinity antagonist that also lacks subunit selectivity, blocked INO, but not ADO, release. Ifenprodil (10 µmol/L), an inhibitor selective for NMDA receptors containing the NR2Bsubunit, completely blocked evoked ADO and INO release. NVP-AAM077 (NVP, 0.4 µmol/L), an inhibitor selective for NMDA receptors containing the NR2Asubunit, did not significantly block evoked release of either ADO or INO. Removal of extracellular Ca2+abolished NMDA-evoked release of both ADO and INO. BAPTA (25 µmol/L), which chelates intracellular Ca2+, had no significant effect on either ADO or INO release unless extracellular Ca2+was also removed. Inhibitors of Ca2+/calmodulin-dependent protein kinase II (CaMKII) prevented NMDA-evoked ADO and INO release and decreased nucleoside transporter function. These data indicate that NMDA-evoked ADO and INO release is dependent on subunit composition of NMDA receptors. As well, NMDA-evoked ADO and INO release requires nucleoside transporters and extracellular Ca2+and is enhanced by activation of CaMKII.
Cyanobacterial toxins and liver diseaseThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba.
Authors: Labine M.A. , Minuk G.Y.
Published: November 2009

Blue-green algae, also known as cyanobacteria, produce a variety of toxins, some of which have been implicated in the pathogenesis of severe and potentially life-threatening diseases in humans. As the growth of cyanobacteria within freshwater lakes increases worldwide, it is important to review our present understanding of their toxicity and potential carcinogenicity to gain insight into how these organisms impact human health. This review addresses each of these topics, with special emphasis given to cyanobacterial hepatotoxins within freshwater environments.
Islet tameness: escape behavior and refuge use in populations of the Balearic lizard (Podarcis lilfordi) exposed to differing predation pressure
Authors: Cooper, Jr. William E. , Hawlena Dror , Pérez-Mellado Valentín
Published: November 2009

Prey often exhibit reduced escape behavior on islands where predators are absent or scarce. Models of escape and refuge use predict that prey from populations having lower predation pressure have shortened flight initiation distance (FID; distance between a predator and a prey when escape begins), reduced distance fled and tendency to enter refuge, and shortened hiding time before emerging from refuge. By ourselves simulating approaching predators, we tested these predictions for two populations of the Balearic lizard, Podarcis lilfordi (Müller, 1927), on the islets of Rei (higher predation pressure) and Aire (lower) adjacent to Menorca. FID, distance fled, and hiding time were shorter and probability of entering refuge was lower on Aire than on Rei, confirming all predictions. All effect sizes were large, indicating major differences in antipredatory behavior between islets. These findings are consistent with data for other lizards on FID and limited data on distance fled and refuge entry. The effect of predation pressure on hiding time is a novel finding. Our results and those of previous studies suggest that relaxation of predation pressure leads to reduced natural selection for maintenance of antipredatory behavior at all stages of predator–prey interactions over a relatively short time span.
Age-specific growth, survival, and population dynamics of female Australian fur seals
Authors: Gibbens J. , Arnould J.P.Y.
Published: November 2009

Postsealing population recovery rates of fur seals and sea lions have differed markedly, perhaps owing to habitat type. Australian fur seals ( Arctocephalus pusillus doriferus Wood Jones, 1925) employ a benthic foraging mode similar to sea lions, and have exhibited similarly slow population recovery. Nonetheless, the population doubled in recent decades, suggesting a recent change in demographic rates. In the present study, the frequency and size of known-age females (n = 297) were used to create body growth and survivorship models. These were compared with models obtained in the 1970s before the recent population increase. Body growth, which is relatively rapid in comparison to other fur seal species, remains unchanged since the 1970s, suggesting that density-dependent effects are absent despite the population increases. Adult survival rates (weighted mean: 0.885) have increased greatly since the 1970s and are the likely mechanism of the recent increases. Total population abundance was estimated to be 4.5 times that of pups. Australian fur seals display high survivorship, rapid body growth, low fecundity, and low population growth rates; all are characteristics typical of benthic foraging sea lions rather than other fur seals.
QUANTITATIVE MEASURE FOR COMMUNITY DETECTION IN WEIGHTED NETWORKS
Authors: YANG SHUZHONG , LUO SIWEI
Published: November 2009

Detecting communities in weighted networks is becoming a challenging and interesting work. In this paper, a novel quantitative measure called weighted normalized modularity density is proposed and optimized to detect communities in weighted networks. Both theoretical certifications on simple schematic examples and numerical experiments on a suit of simulated networks and real-world networks show that the proposed quantitative measure not only improves the resolution limit in optimizing weighted modularity, but also avoids the emergence of negative communities in optimizing weighted modularity density.
ELECTRONIC STRUCTURE AND OPTICAL ABSORPTION OF N-DOPED ZnO
Authors: GUO MEILI , ZHANG X. D.
Published: November 2009

The plane-wave pseudopotential method, based on density functional theory (DFT), has been used to calculate the electronic and optical properties of pure ZnO and N-doped ZnO . The results of density of states (DOS) indicate that the band gap of N-doped ZnO decreases due to the increase of p states in the valence band. Meanwhile, the results of the imaginary part of dielectric function ε2(ω) reveal that the optical transition between O 2p states in the highest valence band and Zn 4s states in the lowest conduction band shifts to the low energy range due to N doping. The optical band gap of ZnO decreases from 3.2 to 2.2 eV after N doping.
INVESTIGATION OF THE BANDWIDTH OF GaAs/AlGaAs QUANTUM WELL INFRARED PHOTODETECTOR
Authors: KONG LING-MIN , ZHANG JIAN , CHENG XING-KUI , ZHANG CUN-XI , WANG RUI
Published: November 2009

A GaAs / AlGaAs multi-quantum well (MQW) structure has been grown by solid source molecular beam epitaxy (MBE) and fabricated to detectors. A spectral response curve of the detector with full width at half maximum (FWHM) = 3.78 μm and peak wavelength = 9.73 μm has been obtained at a bias of E = 3 × 103 Vcm -1 at T = 77 K. We study the bandwidth of the GaAs / AlGaAs quantum well infrared photodetector (QWIP) by using effective mass approximation. It is found that the transmissivity of the electron through the potential barrier reaches its maximum value (T = 1) on the condition of resonance transmission in a multi-quantum well structure, if the energy state is defined as a conduction state when the transmissivity of electron through the potential barrier on which is bigger than 1/2, then, a series of separated conduction microbands were formed above the barriers which consist of conduction states. Under the influence of an external electric field, the conduction microbands stagger periodically among the quantum wells to form a Wannier–Stark ladder. When optical excitation occurs, electrons not only vertically transit from Fermi level EF in a quantum well to conduction microbands above the well, but also obliquely transit to the conduction microbands above the neighboring well, and the formed photocurrent peaks overlap together; consequently, the bandwidth of the photoresponsive spectrum is improved. The calculated bandwidth of the photocurrent spectrum agrees well with the measured one in our experiment.
DECOHERENCE OF THE TRIANGULAR BOUND POTENTIAL QUANTUM DOT QUBIT
Authors: SUN JIA-KUI , LI HONG-JUAN , XIAO JING-LIN
Published: November 2009

We study the eigenenergies and the eigenfunctions of the ground and the first excited states of an electron, which is strongly coupled to the LO-phonon in a quantum dot with triangular bound potential by using the Pekar variational method. This system may be used as a two-level qubit. Our numerical results indicate that the decoherence rate will decrease with increasing the confinement length of the quantum dot (QD) and decrease with increasing electron-LO-phonon coupling constant. The influences of the polar angle on the decoherence rate are dominant when the coupling constant increases, while the effects of the polar angle on that are strong when the confinement length increases. Meanwhile, the decoherence rate varies periodically with respect to the polar angle.
MIXED-ORDER KINETICS MODEL FOR OPTICALLY STIMULATED LUMINESCENCE
Authors: KITIS G. , FURETTA C. , PAGONIS V.
Published: November 2009

The theory of mixed-order kinetics is well-established for the description of single thermoluminescence (TL) glow-peaks. The main advantage of mixed-order kinetics relative to the more widely used general-order kinetic theory is that the former is physically meaningful whereas the latter is entirely empirical. In the case of optically stimulated luminescence (OSL) either non-first-order or second-order kinetics are studied using the empirical general-order kinetics theory. In the present work, expressions for mixed-order kinetics are derived for OSL curves. A peak shape parameter for linear modulation OSL is developed and special mixed-order expressions are derived for use in the computerized OSL curve deconvolution analysis.
EXPERIMENTAL VERIFICATION OF A FOUR-DIMENSIONAL CHUA'S SYSTEM AND ITS FRACTIONAL ORDER CHAOTIC ATTRACTORS
Authors: LIU LING , LIU CHONGXIN , ZHANG YANBIN
Published: November 2009

This paper introduces a modified Chua's system which is a smooth four-dimensional continuous-time autonomous chaotic system with a cubic nonlinearity. Some dynamical behaviors of this 4-D Chua's system are further investigated by means of Poincaré mapping, parameter phase portraits, equilibrium points, bifurcations and calculated Lyapunov exponents. Moreover, using RC-opamp and analog multiplier we describe a simple electronic circuit for hardware implementation of the 4-D Chua's system which differ from previously reported Chua's circuits. Various attractors of experimental results from this chaotic oscillator are in good agreement with theoretical analysis. In particular, based on the approximation theory of fractional-order operator, a relevant analog circuit diagram of this fractional-order modified Chua's system is designed with α = 0.9. Observation results demonstrate that chaos exists indeed in this fractional-order modified Chua's system with an order as low as 3.6. This fractional-order oscillation circuit, for the first time in the literature, realizes high-dimensional Chua's chaotic system.
AUTOMATED BIFURCATION ANALYSIS FOR NONLINEAR ELLIPTIC PARTIAL DIFFERENCE EQUATIONS ON GRAPHS
Authors: NEUBERGER JOHN M. , SIEBEN NÁNDOR , SWIFT JAMES W.
Published: November 2009

We seek solutions u ∈ ℝn to the semilinear elliptic partial difference equation -Lu + fs(u) = 0, where L is the matrix corresponding to the Laplacian operator on a graph G and fs is a one-parameter family of nonlinear functions. This article combines the ideas introduced by the authors in two papers: (a) Nonlinear elliptic partial difference equations on graphs (J. Experimental Mathematics, 2006), which introduces analytical and numerical techniques for solving such equations, and (b) Symmetry and automated branch following for a semilinear elliptic PDE on a fractal region (SIAM J. Dynamical Systems, 2006), wherein we present some of our recent advances concerning symmetry, bifurcation and automation for PDE.

We apply the symmetry analysis found in the SIAM paper to arbitrary graphs in order to obtain better initial guesses for Newton's method, create informative graphics, and better understand the role of symmetry in the underlying variational structure. We use two modified implementations of the gradient Newton–Galerkin algorithm (GNGA, Neuberger and Swift) to follow bifurcation branches in a robust way. By handling difficulties that arise when encountering accidental degeneracies and higher-dimensional critical eigenspaces, we can find many solutions of many symmetry types to the discrete nonlinear system. We present a selection of experimental results which demonstrate our algorithm's capability to automatically generate bifurcation diagrams and solution graphics starting with only an edgelist of a graph. We highlight interesting symmetry and variational phenomena.
CONDUCTIVITY OF THE SELF-SIMILAR LORENTZ CHANNEL
Authors: BARRA FELIPE , GILBERT THOMAS , REYES SEBASTIAN
Published: November 2009

The self-similar Lorentz billiard channel is a spatially extended deterministic dynamical system which consists of an infinite one-dimensional sequence of cells whose sizes increase monotonously according to their indices. This special geometry induces a drift of particles flowing from the small to the large scales. In this article we further explore the dynamical and statistical properties of this billiard. We derive from the ensemble average of the velocity a conductivity formula previously obtained by invoking the equality between phase-space contraction rate and the phenomenological entropy production rate. This formula is valid close to equilibrium. We also review other transport and ergodic properties of this billiard.
HYSTERESIS AND VORTICES DYNAMICS IN A TURBULENT FLOW
Authors: BURGUETE JAVIER , DE LA TORRE ALBERTO
Published: November 2009

Recent results about the slow dynamics present in a fully developed turbulent flow are reported. In a previous paper [de la Torre & Burguete, 2007] we showed that the mean velocity field in a turbulent flow bifurcates subcritically breaking some symmetries of the problem and becomes time-dependent because of equatorial vortices moving with a precession movement. This subcriticality produces a bistable regime, whose main characteristics were successfully reproduced using a three-well potential model with additive noise. In this paper we present the characterization of the hysteresis region, not previously observed, in this bifurcation. This hysteresis appears only for an extremely small range of parameters.
VARIATIONAL PRINCIPLES IN IMAGE PROCESSING AND THE REGULARIZATION OF ORIENTATION FIELDS
Authors: CISTERNAS JAIME , GÁLVEZ MARCELO , STIELTJES BRAM , LAUN FREDERIK B.
Published: November 2009

Variational principles and partial differential equations have proved to be fundamental elements in the mathematical modeling of extended systems in physics and engineering. Of particular interest are the equations that arise from a free energy functional. Recently variational principles have begun to be used in Image Processing to perform basic tasks such as denoising, debluring, etc. Great improvements can be achieved by selecting the most appropriate form for the functional.

In this article we show how these ideas can be applied not just to scalar fields (i.e. grayscale images) but also to curved manifolds such as the space of orientations. This work is motivated by the denoising of images acquired with Magnetic Resonance scanners using diffusion-sensitized magnetic gradients.
SHAPE AND SIZE EFFECTS IN LOCALIZED HEXAGONAL PATTERNS
Authors: ESCAFF DANIEL , DESCALZI ORAZIO
Published: November 2009

We study the process of localization of a hexagonal pattern in a uniform background, specifically, the role played by the shape and size of the domain where the hexagonal pattern is confined. We base our analysis on a numerical study of a Swift–Hohenberg type equation (which exhibits coexistence between hexagons and a uniform state), and in a scale expansion to estimate the stress undergoing by the interface (the curve that separates the hexagonal phase from the uniform one). Our scaling approach supplies us a good physical picture of what we observe numerically.
AMPLITUDE EQUATION FOR STATIONARY CONVECTION IN A ROTATING BINARY FERROFLUID
Authors: LAROZE D. , MARTINEZ-MARDONES J. , PÉREZ L. M. , RAMESHWAR Y.
Published: November 2009

We report both theoretical and numerical results on convection for a binary magnetic mixture under rotation. We focus on the stationary convection for idealized boundary conditions. We obtain explicit expressions of convective thresholds in terms of the control parameters of the system. Close to bifurcation, the coefficients of the corresponding amplitude equation are determined analytically. The effect of the magnetophoresis and Kelvin force are emphasized and, finally, the nature of the bifurcation is discussed.
DYNAMICS OF AN INTERFACE CONNECTING A STRIPE PATTERN AND A UNIFORM STATE: AMENDED NEWELL–WHITEHEAD–SEGEL EQUATION
Authors: ROJAS RENÉ G. , ELÍAS RICARDO G. , CLERC MARCEL G.
Published: November 2009

The dynamics of an interface connecting a stationary stripe pattern with a homogeneous state is studied. The conventional approach which describes this interface, Newell–Whitehead–Segel amplitude equation, does not account for the rich dynamics exhibited by these interfaces. By amending this amplitude equation with a nonresonate term, we can describe this interface and its dynamics in a unified manner. This model exhibits a rich and complex transversal dynamics at the interface, including front propagations, transversal patterns, locking phenomenon, and transversal localized structures.
Convolutions with the Continuous Primitive Integral
Authors: Talvila Erik
Published: November 2009

If F is a continuous function on the real line and f = F′ is its distributional derivative, then the continuous primitive integral of distribution f is . This integral contains the Lebesgue, Henstock‐Kurzweil, and wide Denjoy integrals. Under
the Alexiewicz norm, the space of integrable distributions is a Banach space. We define the
convolution for f an integrable distribution and g a function of bounded variation or an L1 function. Usual properties of convolutions are shown to hold: commutativity, associativity, commutation with translation. For g of bounded variation,
f∗g is uniformly continuous and we have the estimate ∥f∗g∥∞ ≤ ∥f∥∥g∥ℬ𝒱, where ∥f∥ = supI|∫If| is the Alexiewicz norm. This supremum is taken over all intervals
I ⊂ ℝ. When g ∈ L1, the estimate is ∥f∗g∥ ≤ ∥f∥∥g∥1. There are results on differentiation and integration of convolutions. A type of Fubini theorem is proved for the continuous primitive integral.
Intra-Articular Osteotomy for Distal Humerus Malunion
Authors: Marti René K. , Doornberg Job
Published: November 2009

Intra-articular osteotomy is considered in the rare case of malunion after a fracture of the distal humerus to restore humeral alignment and gain a functional arc of elbow motion. Traumatic and iatrogenic disruption of the limited blood flow to the distal end of the humerus resulting in avascular necrosis of capitellum or trochlea is a major pitfall of the this technically challenging procedure. Two cases are presented which illustrate the potential problems of intra-articular osteotomy for malunion of the distal humerus.
Throughput of Type II HARQ‐OFDM/TDM Using MMSE‐FDE in a Multipath Channel
Authors: Gacanin Haris , Adachi Fumiyuki
Published: November 2009

In type II hybrid ARQ (HARQ) schemes, the uncoded information bits are transmitted first, while the error correction parity bits are sent upon request. Consequently, frequency diversity cannot be exploited during the first transmission. In this paper, we present the use of OFDM/TDM with MMSE‐FDE and type II HARQ to increase throughput of OFDM due to frequency diversity gain.
Strong Convergence Theorems for Infinitely Nonexpansive Mappings in Hilbert Space
Authors: Chen Yi-An
Published: November 2009

We introduce a modified Ishikawa iterative process for approximating a fixed point of two infinitely nonexpansive self-mappings by using the hybrid method in a Hilbert space and prove that the modified Ishikawa iterative sequence converges strongly to a common fixed point of two infinitely nonexpansive self-mappings.
Common Fixed Points for Multimaps in Metric Spaces
Authors: Espínola Rafa , Hussain Nawab
Published: November 2009

We discuss the existence of common fixed points in uniformly convex metric spaces for single-valued pointwise asymptotically nonexpansive or nonexpansive mappings and multivalued nonexpansive, "Equation missing"-nonexpansive, or "Equation missing"-semicontinuous maps under different conditions of commutativity.
In Pursuit of the Least Luminous Galaxies
Authors: Willman Beth
Published: November 2009

The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter. Their resolved stellar populations also facilitate detailed studies of their history and mass content. To fully exploit this potential requires a well‐defined census of virtually invisible galaxies to the faintest possible limits and to the largest possible distances. I review the past and present impacts of survey astronomy on the census of Milky Way dwarf galaxy companions and discuss the future of finding ultra‐faint dwarf galaxies around the Milky Way and beyond in wide‐field survey data.
A Hybrid Projection Algorithm for Finding Solutions of Mixed Equilibrium Problem and Variational Inequality Problem
Authors: Cianciaruso Filomena , Marino Giuseppe , Muglia Luigi , Yao Yonghong
Published: November 2009

We propose a modified hybrid projection algorithm to approximate a common fixed point of a "Equation missing"-strict pseudocontraction and of two sequences of nonexpansive mappings. We prove a strong convergence theorem of the proposed method and we obtain, as a particular case, approximation of solutions of systems of two equilibrium problems.
Drug Resistance in Visceral Leishmaniasis
Authors: Maltezou Helena C.
Published: November 2009

Visceral leishmaniasis remains a public health problem worldwide. This illness was included by the World Health Organization in the list of neglected tropical diseases targeted for elimination by 2015. The widespread emergence of resistance to pentavalent antimonials in India where half cases occur globally and the unavailability of a vaccine in clinical use constitute major obstacles in achieving this goal. The last decade new antileishmanials became available, including the oral agent miltefosine. However, in poor endemic countries their wide use was curtailed because of the high costs, and also due to concerns of toxicity and emergence of resistance. Various mechanisms of antileishmanial resistance were identified recently in field isolates. Their elucidation will boost the design of new drugs and the molecular surveillance of resistance. Combination regimens should be evaluated in large trials. Overall, the development of antileishmanials has been generally slow; new drugs are needed. In order to control visceral leishmaniasis worldwide, treatment advances should become affordable in the poorest countries, where they are needed most.
The Alkylphospholipid Perifosine Induces Apoptosis and p21-Mediated Cell Cycle Arrest in Medulloblastoma
Authors: Kumar Anil , Fillmore Helen L. , Kadian Renu , Broaddus William C. , Tye Gary W. , Van Meter Timothy E.
Published: November 2009

Medulloblastoma is the most common malignant cancer of the central nervous system in children. AKT kinases are part of a survival pathway that has been found to be significantly elevated in medulloblastoma. This pathway is a point of convergence for many growth factors and controls cellular processes that are critical for tumor cell survival and proliferation. The alkyl-phospholipid perifosine [octadecyl-(1,1-dimethyl-4-piperidylio) phosphate] is a small molecule inhibitor in clinical trials in peripheral cancers which acts as a competitive inhibitor of AKT kinases. Medulloblastoma cell cultures were used to study the effects of perifosine response in preclinical studies in vitro. Perifosine treatment led to the rapid induction of cell death in medulloblastoma cell lines, with pronounced suppression of phosphorylated AKT in a time-dependent and concentration-dependent manner. LD50 concentrations were established using viability assays for perifosine, cisplatin, and etoposide. LD50 treatment of medulloblastoma cells with perifosine led to the cleavage of caspase 9, caspase 7, caspase 3, and poly-ADP ribosylation protein, although caspase 8 was not detectable. Combination single-dose treatment regimens of perifosine with sublethal doses of etoposide or irradiation showed a greater than additive effect in medulloblastoma cells. Lower perifosine concentrations induced cell cycle arrest at the G1 and G2 cell cycle checkpoints, accompanied by increased expression of the cell cycle inhibitor p21cip1/waf1. Treatment with p21 small interfering RNA prevented perifosine-induced cell cycle arrest. These findings indicate that perifosine, either alone or in combination with other chemotherapeutic drugs, might be an effective therapeutic agent for the treatment of medulloblastoma. (Mol Cancer Res 2009;7(11):1813–21)
Second Allogeneic Stem Cell Transplantation in Myeloid Malignancies
Authors: Hartwig Maite , Ocheni Sunday , Asenova Svetlana , Wiedemann Bettina , Zabelina Tatjana , Ayuk Francis , Kabisch Hartmut , Erttmann Rudolf , Kröger Nicolaus , Zander Axel Rolf , Bacher Ulrike
Published: November 2009

For patients with myeloid malignancies who relapse after allogeneic stem cell transplantation (allo-SCT), one salvage option is a second SCT. We retrospectively analyzed outcomes of the second allo-SCT in 25 patients who received at least 2 allografts from related/unrelated donors due to relapse of acute myeloid leukemia, myelodysplastic syndrome or myelofibrosis after the first SCT. A minority of the acute myeloid leukemia/myelodysplastic syndrome patients had reached complete hematological remission before the second SCT (6/25, 24%). Reduced conditioning strategies were performed in the majority (n = 23). Complete remission was achieved in all 21 cases with available data after the second SCT, but relapse was seen in 11/25 patients (44%). After a median follow-up of 18 months (range 6–47), 8/25 patients (32%) were still alive, and of those, 6 (24%) were in stable remission. In 9 cases mortality was associated to relapse and in 8 cases to transplant-related causes (treatment-related mortality; 8/25, 32%). In conclusion, a second SCT offers the chance of stable remission for some patients relapsing with a myeloid malignancy after a first allo-SCT, although high treatment-related mortality and relapse rates remain a problem. Efforts should concentrate on an optimization of conditioning strategies, immunosuppression and post-transplant surveillance for this specific situation.
Reference Values for Doppler Parameters of the Fetal Anterior Cerebral Artery throughout Gestation
Authors: Benavides-Serralde J.A. , Hernández-Andrade E. , Figueroa-Diesel H. , Oros D. , Feria L.A. , Scheier M. , Figueras F. , Gratacós E.
Published: November 2009

Aim: To construct normal reference values for Doppler parameters in 2 anatomical segments of the fetal anterior cerebral artery (ACA) throughout pregnancy. Methods: The ACA was evaluated in 373 normally growing fetuses from 20 to 40 weeks of gestation. The first segment of the ACA (ACA-S1) was recorded just after its origin from the internal carotid artery in the same plane as the middle cerebral artery (MCA). The second segment (ACA-S2) was recorded distal to the outlet of the anterior communicating artery. Results: The ACA pulsatility index (PI) behaved similarly in both segments, with a constant increase until 28 weeks followed by a decrease until the end of pregnancy [ACA-S1 PI = 3.49 – 0.37 × gestational age (GA) – (0.0063 × GA2), SD = 0.6 – 0.061 × GA – (0.001 × GA2); ACA-S2 PI = 1.54 – 0.22 × GA – (0.0037 × GA2), SD = 0.206 + (0.0037 × GA)]. Peak systolic velocities in both segments showed a constant increase from 20 to 40 weeks of gestation. No significant differences were found between the 2 segments with regard to any Doppler parameter. However, the angle of insonation and the time spent on examination were significantly lower and reproducibility was better for ACA-S1. Conclusion: Despite showing similar Doppler values, ACA-S1 has a higher reliability than ACA-S2 and can be recorded in the same anatomical projection as the MCA.
Omental Fat Receptor Interacting Protein 140 mRNA Expression in Women with Polycystic Ovary Syndrome
Authors: Seow Kok-Min , Tsai Yieh-Loong , Juan Chi-Chang , Huang Lee-Wen , Hwang Jiann-Loung , Ho Low-Tone
Published: November 2009

Background: Receptor interacting protein 140 (RIP140) is a co-repressor and essential for oocytes released by the ovary during ovulation. The aim of the study is to investigate adipose mRNA expression of RIP140 in women with polycystic ovary syndrome (PCOS) before and 3 months after laparoscopic ovarian electrocauterization (LOE). Methods: Adipose tissues obtained from 15 women with PCOS before and after LOE were analyzed. Ten lean, age- and BMI-matched non-PCOS women served as controls. Gene expression of RIP140 was quantified by reverse transcriptase-polymerase chain reaction. Results: The overall spontaneous ovulation rate was 73.3% in PCOS after the LOE procedure. However, no difference was found in the expression of RIP140 between women with PCOS before LOE and controls or between PCOS before and after LOE. No difference was found in RIP140 expression between obese and lean women with PCOS, or between obese PCOS and lean controls. Further, there was no correlation between RIP140 and fasting or 2-hour glucose or insulin, homeostasis model insulin resistance index (HOMAIR), and fasting glucose-to-insulin ratio (G0/I0) in women with PCOS. Conclusion: RIP140 gene does not play any pivotal role in the process of ovulation, insulin resistance or fat accumulation in women with PCOS.
Preventing Restenosis after Implantation of Bare Stents with Oral Rapamycin: A Randomized Angiographic and Intravascular Ultrasound Study with a 5-Year Clinical Follow-Up
Authors: Cernigliaro Carmelo , Sansa Mara , Vitrella Giancarlo , Verde Alessandro , Bongo Angelo Sante , Giuliani Luigi , Novelli Eugenio
Published: November 2009

Objectives: To establish the efficacy of oral rapamycin at a dose of 2 mg for 1 month at reducing the 6-month restenosis rate after the implantation of bare metal stents. Methods: A prospective, 1:1 randomized, single-blind, placebo-controlled study was conducted in 108 consecutive patients assigned immediately after stent implantation to oral rapamycin (4 mg loading dose followed by 2 mg daily for 30 days) or a placebo. Results: Rapamycin was maintained in 98% of patients. Angiographic in-stent binary restenosis was 14.3% in the rapamycin group versus 32.1% in the placebo group, with a relative risk (RR) of 0.45 (95% CI 0.24–0.84, p = 0.015). The rapamycin blood concentration at 15 days correlated with binary restenosis (p = 0.044). The volume obstructions found by intravascular ultrasound for the rapamycin and the placebo groups were 18.1±10.7 and 27.1±15.7% (p = 0.002), respectively. Major adverse cardiac events at a 5-year follow-up were 31.5% for the rapamycin group and 50.0% for the placebo group (RR 0.63, 95% CI 0.39–1.01, p = 0.078). Conclusions: Oral rapamycin significantly reduces the incidence of restenosis at follow-up compared to a placebo.We believe these findings deserve further testing in larger trials.