bluuebunny/crossref_metadata_2025 huggingface dataset:
Anterior chamber depth and iridocorneal angle in healthy White subjects: effects of age, gender and refraction
Authors: Rüfer Florian , Schröder Anke , Klettner Alexa , Frimpong‐Boateng Adjoa , Roider Johann B , Erb Carl
Published: June 2009

Acta Ophthalmol. 2010: 88: 885–890

Purpose:  Prior to phakic intraocular lens implantation, it is important to obtain precise knowledge of the anterior chamber depth (ACD). Accurate topographic evaluation of the iridocorneal angle is helpful in estimating risk for angle‐closure glaucoma. This study investigated the use of the Orbscan II system to measure ACD and the iridocorneal angle in healthy subjects and assessed the influences of age, gender and spherical equivalent on these parameters.

Methods:  The Orbscan II system was used to determine the ACD and iridocorneal angle in eight different positions in 390 healthy White subjects with a mean age of 41 ± 16 years (range 10–80 years). The sample included 242 male and 148 female subjects. The influences of age, gender and spherical equivalent were assessed using multiple regression analysis.

Results:  Mean ACD was 2.87 ± 0.04 mm in male subjects and 2.81 ± 0.37 mm in female subjects. The explanatory variables relevant to the ACD were age (partial regression coefficient B = − 0.0115, p < 0.0001), spherical equivalent (B = − 0.0562, p < 0.0001) and gender (B = 0.0996, p = 0.0036). The mean iridocorneal angle (MIA) was 30.7 ± 2.0 ° in male and 31.6 ± 2.1 ° in female subjects. The variables relevant to the MIA were gender (B = − 0.865, p < 0.0001), age (B = − 0.017, p = 0.0007) and spherical equivalent (B = − 0.121, p = 0.001). The superior iridocorneal angle displayed the strongest negative correlation with age, whereas the temporal angle exhibited the least correlation with age.

Conclusions:  The decline in ACD appears to be linear with age, amounting to a mean of 0.58 mm over 50 years. This may become clinically relevant in the use of phakic intraocular lenses. In addition, the angle is more severely constricted in the superior quadrant than in the temporal quadrant.
Astragalus ansinii sp. nov. (Fabaceae) from Turkey, and a contribution to the sectional taxonomy
Authors: Uzun Alper , Terzioğlu Salih , Palabaş‐Uzun Seyran , Coşkunçelebi Kamil
Published: June 2009

Astragalus ansinii A. Uzun, Terzioğlu & S. Palabaş‐Uzun, a new species from northeast Anatolia is described and illustrated. It belongs to Astragalus sect. Hypoglottis Bunge, but the characters in combination do not match completely with this section because the legumes, leaves and calyces are glabrous. This local endemic is known from two adjacent localities with several individuals. Astragalus ansinii is morphologically most similar to A. viridissimus but differs mainly by indumentum, numbers of pairs of leaflets and seed shape together with metric data related to calyx, standard and peduncle. Nuclear ITS was analysed in both species and was found to be highly similar. In addition, the seed morphology, distribution, conservation status and ecology of both species are discussed.
Biogeographical patterns of soil bacterial communities
Authors: Dequiedt Samuel , Thioulouse Jean , Jolivet Claudy , Saby Nicolas P.A. , Lelievre Mélanie , Maron Pierre‐Alain , Martin Manuel P. , Prévost‐Bouré Nicolas Chemidlin , Toutain Benoit , Arrouays Dominique , Lemanceau Philippe , Ranjard Lionel
Published: June 2009

This study provides the first maps of variations in bacterial community structure on a broad scale based on genotyping of DNA extracts from 593 soils from four different regions of France (North, Brittany, South‐East and Landes). Soils were obtained from the soil library of RMQS (‘Réseau de Mesures de la Qualité des Sols’ = French soil quality monitoring network). The relevance of a biogeographic approach for studying bacterial communities was demonstrated by the great variability in community structure and specific geographical patterns within and between the four regions. The data indicated that the distribution of bacterial community composition might be more related to local factors such as soil type and land cover than to more global factors such as climatic and geomorphologic characteristics. Furthermore, the regional pools of biodiversity could be ordered: South‐East ≥ North > Brittany > Landes, according to the observed regional variability of the bacterial communities, which could be helpful for improving land use in accordance with soil biodiversity management.
A survey of TonB‐dependent receptors in fluorescent pseudomonads
Authors: Cornelis Pierre , Bodilis Josselin
Published: June 2009

For bacteria with an aerobic lifestyle, iron is in the oxidized Fe3+ form, hence poorly soluble. The solution is the synthesis and excretion of siderophores with a high affinity for iron. These ferrisiderophores are recognized by TonB‐dependent outer membrane receptors in Gram‐negative bacteria. Haem is also a source of iron and is captured via TonB‐dependent receptors as well. In many cases bacterial genomes encode genes for receptors for siderophores produced by other microorganisms (xenosiderophores). Pseudomonads are known for their high adaptive capacity and it is therefore not surprising to find a relatively large number of genes encoding these receptors. In this study we analysed the genomes of three fluorescent pseudomonads available in the Pseudomonas genome database (http://www.pseudomonas.com; P. aeruginosa, P. putida, P. syringae) in order to extract the genes coding for TonB‐dependent receptors. As expected we observed differences between species for the number of receptors. We also report differences within species, suggesting the acquisition of some genes via horizontal gene transfer, including those coding for the ferripyoverdine receptors. We also report cases where duplications of receptor genes are observed and the presence of ‘receptor islands’. Our study strongly supports the notion of ‘core’ and ‘accessory’ TonB‐dependent receptors within each species, with the ferripyoverdine receptors belonging to the last category.
Evaluation of a modified thrombelastography assay initiated with recombinant human tissue factor in clinically healthy horses
Authors: Leclere Mathilde , Lavoie Jean‐Pierre , Dunn Marilyn , Bédard Christian
Published: June 2009

Background: Thrombelastography (TEG) is used to evaluate the viscoelastic properties of blood during clotting and provides a global assessment of hemostasis and clot lysis. TEG analysis initiated with recombinant human tissue factor (TF) has not been evaluated in clinically healthy horses.

Objectives: The purpose of this study was to determine whether TEG results are affected by the time elapsed between sampling and analysis (storage time) of equine blood samples and to establish a preliminary equine reference interval for a modified TEG assay, using recombinant human TF to initiate coagulation.

Methods: Citrated blood samples were obtained from 20 clinically healthy adult horses. Thirteen samples were stored for 30, 60, and 120 minutes at room temperature before TEG analysis. Coagulation was initiated by adding 20 μL of CaCl2 to 330 μL of blood and 10 μL of diluted recombinant TF for a final dilution of 1:3600. Reaction (R) and clotting (K) times, angle (α), and maximum amplitude (MA) were compared between time points. A preliminary reference interval (minimum–maximum values) was determined using data from all 20 horses after 30 minutes of sample storage.

Results: There was a significant effect of storage time on R, K, and α but not MA. Reference intervals were: R, 3.65–6.4 minutes; K, 1.8–5.45 minutes; α, 33.4–66.2°; MA, 41.2–64.1 mm; lysis at 30 minutes post‐MA (LY30), <2.75%; and lysis at 60 minutes post‐MA (LY60), 1.55–9.5%.

Conclusions: TEG can be performed on equine citrated blood samples using recombinant human TF to activate clot formation. TEG parameters were significantly affected by storage time, suggesting an incomplete inhibition of coagulation in citrated blood.
Design, optimization, and application of a conventional PCR assay with an internal control for detection of ‘CandidatusMycoplasma turicensis’ 16S rDNA in domestic cats from Brazil
Authors: Santos Andrea P. , Messick Joanne B. , Biondo Alexander W. , Oliveira Simone T. , Pedralli Viviane , Lasta Camila S. , Lacerda Luciana A. , Esteves Vanessa S. , Hofmann‐Lehmann Regina , Willi Barbara , González Félix H. D.
Published: June 2009

Background:‘CandidatusMycoplasma turicensis’ (CMtc) is a hemotrophic bacterial species that can, alone or in combination, induce anemia in cats. The diagnostic test of choice for hemoplasma infections is PCR. Conventional PCR assays have been developed for the detection ofMycoplasma haemofelis(Mhf) and ‘CandidatusM. haemominutum’ (CMhm) but not forCMtc. Although real‐time PCR assays have been reported for all of the feline hemoplasmas, the expense of necessary instrumentation precludes its use in Brazil and many other countries.

Objectives:The goals of this study were to develop and optimize a conventional PCR assay to diagnoseCMtc using an internal control to detect false‐negative results, and to evaluate the occurrence ofCMtc infection in domestic cats from Brazil.

Methods:Species‐specific primers were designed and a PCR assay was developed for the detection ofCMtc 16S rDNA in cat blood. Sensitivity was determined by serial 10‐fold dilutions of plasmid and DNA extracted from blood from an experimentally infected cat. EDTA blood samples from 373 cats were collected. DNA was extracted using a silica‐based protocol and tested using the PCR assay.

Results:Primer concentration, annealing temperature, and MgCl2concentration were optimized in the presence and absence of the internal control. Two samples negative for the internal control were excluded. Of the remaining 371 samples (117 healthy and 254 unhealthy cats), 17 (4.6%) were positive forCMtc.

Conclusion:These results demonstrate the utility of an optimized PCR assay to detectCMtc in feline blood samples. We also report for the first time the prevalence ofCMtc infection in domestic cats in Brazil.
Serum thyroxine concentrations in clinically healthy pet guinea pigs (Cavia porcellus)
Authors: Müller Kerstin , Müller Elisabeth , Klein Ruth , Brunnberg Leo
Published: June 2009

Background:Guinea pigs (Cavia porcellus) are often presented as patients in veterinary practice. Nevertheless, only limited information is available about endocrine diseases or thyroxine reference values for the species.

Objective:The aim of this study was to determine serum thyroxine concentrations in a well‐defined population of clinically healthy pet guinea pigs.

Methods:Between October 2007 and July 2008, serum samples were collected from 40 clinically healthy guinea pigs of different sexes, ages, and breeds that were presented to our clinic for a general health check or for castration. Pregnant females were excluded from the study. Thyroxine concentration was measured using a chemiluminescence test (Immulite 2000 Canine Total T4).

Results:Thyroxine concentrations ranged from 14.2 to 66.9 nmol/L (1.1–5.2 μg/dL) with a median value of 27.0 nmol/L (2.1 μg/dL). Females (n=16) had significantly (P=.039; Mann–WhitneyU‐test) lower thyroxine values than castrated males (n=8), whereas no differences were found between females and intact males (n=16) or between intact and castrated males. No significant correlation was found between thyroxine concentration and age.

Conclusion:This is the first report of serum thyroxine reference values for a well‐defined population of healthy pet guinea pigs as measured by a chemiluminescence assay. The results were higher than those previously reported for this species and emphasize the importance of using appropriate reference intervals for the diagnosis of hyperthyroidism.
Differential cell counts in canine cytocentrifuged bronchoalveolar lavage fluid: a study on reliable enumeration of each cell type
Authors: De Lorenzi Davide , Masserdotti Carlo , Bertoncello Diana , Tranquillo Vito
Published: June 2009

Background:Bronchoalveolar lavage (BAL) allows cell recovery from the lower respiratory tract; differential cell counts of BAL fluid gives important information in the assessment of various bronchial and pulmonary diseases. To the best of our knowledge no study has investigated the relation between the number of cells counted and the reproducibility of BAL fluid differential cell counts.

Objective:The purpose of this study was to investigate using statistical methods how many cells should be counted in cytocentrifuged BAL fluid preparations in order to obtain a reliable enumeration of each cell type.

Methods:BAL fluid samples from dogs with suspected bronchopulmonary disease were obtained during fiberoptic bronchoscopy with a standardized protocol. Differential cell counts were performed on May–Grünwald–Giemsa‐stained cytocentrifuged preparations by 2 independent observers. Reproducibility for the enumeration of each cell type was expressed as the intraclass correlation coefficient. We considered a threshold level of ≥0.90 to be high and a threshold level of ≥0.85 to be adequate.

Results:Forty BAL fluid samples were included in the study. For neutrophils, alveolar macrophages, and eosinophils high reproducibility was reached by counting 200 cells; adequate reproducibility was reached for lymphocytes and bronchial epithelial cells by counting 500 cells.

Conclusions:A 500‐cell differential count is required for all types of cells to be quantified with adequate reproducibility in canine cytocentrifuged BAL fluid samples.
Effects of in vitro hemodilution of canine blood on platelet function analysis using the PFA‐100
Authors: Clancey Noel , Burton Shelley , Horney Barbara , MacKenzie Allan , Nicastro Andrea , Côté Etienne
Published: June 2009

Background:The platelet function analyzer (PFA)‐100 is a point‐of‐care instrument previously evaluated in humans and dogs. In both species, artificially prolonged platelet closure time (CT) occurs with anemia. Reliability of the analyzer in dogs becomes a concern when the HCT is between 0.25 and 0.35 L/L.

Objective:The objective of this study was to further define the level of HCT at which CT is prolonged, using in vitro diluted canine blood.

Methods:Citrated whole blood samples were collected from 22 healthy dogs. Initial HCT was determined and autologous platelet‐rich plasma was added to samples to achieve HCTs of 0.33, 0.30, and 0.27 L/L. CT was determined in duplicate on the PFA‐100 using collagen/adenosine‐5′‐diphosphate cartridges.

Results:Compared with the initial CT in samples with HCT 0.39–0.54 L/L (CT mean±SD=57.8±5.75 seconds), significantly prolonged CTs were found in hemodiluted samples with HCT 0.33 L/L (61.1±4.64 seconds), 0.30 L/L (64.3±6.79 seconds), and 0.27 L/L (70.8±7.90 seconds) (P=0.029; repeated measures ANOVA).

Conclusion:Although statistical differences were found, further studies are needed to determine the clinical significance of the mild prolongation in CT associated with mild anemia. Until then, dogs with HCTs slightly <0.35 L/L should be evaluated cautiously for platelet dysfunction using the PFA‐100.
ASYMPTOTIC NORMALIZATION COEFFICIENTS FOR 7Be(p, γ)8B FROM RMF CALCULATION
Authors: WANG CHENGBIN , DONG TIEKUANG , ZHU Z. Y. , REN ZHONGZHOU
Published: June 2009

The asymptotic normalization coefficient (ANC) method is used to determine the cross sections of peripheral reactions at astrophysical energies because of existence of the Coulomb barriers. In this paper, we address an estimation of the ANC of 8 B with its single particle wavefunction obtained within the framework of relativistic mean field (RMF) theory. We test the force parameters used in the RMF theory by comparing the calculated structure properties of A = 7–9 drip-line nuclei with experimental results. Utilizing the corrected bound wavefunction of 8 B , the ANC [Formula: see text] is obtained and that indicates the S17(0) is 18.07 eV b. Additionally, we find that the root-mean-square (rms) radius for the loosely bound proton in 8 B is 3.98 fm. This confirms that 8 B has a proton halo structure.
GEODESIC STRUCTURE OF THE SCHWARZSCHILD BLACK HOLE IN RAINBOW GRAVITY
Authors: LEIVA CARLOS , SAAVEDRA JOEL , VILLANUEVA JOSÉ
Published: June 2009

In this paper we study the geodesic structure of the Schwarzschild black hole in rainbow gravity analyzing the behavior of null and time-like geodesic. We find that the structure of the geodesics essentially does not change when the semiclassical effects are included. However, we can distinguish different scenarios if we take into account the effects of rainbow gravity. Depending on the type of rainbow functions under consideration, inertial and external observers see very different situations in radial and non-radial motion of a test particle.
AN ASYMMETRIC FAMILY OF COSMIC STRINGS
Authors: SÁTIRO CAIO , DE M. CARVALHO A. M. , MORAES FERNANDO
Published: June 2009

Inspired by condensed matter physics we propose a new, asymmetric, family of cosmic strings. These strings present a conical curvature singularity plus a surrounding region of alternating positive and negative curvature as the azimuthal angle is changed. Their sources include both positive and negative mass density regions.
DIELECTRIC BRANES IN NONTRIVIAL BACKGROUNDS
Authors: ILLAN IGNACIO ALVAREZ
Published: June 2009

We present a procedure to evaluate the action for dielectric branes in nontrivial backgrounds. These backgrounds must be capable to be taken into a Kaluza–Klein form, with some nonzero wrapping factor. We derive the way this wrapping factor is gauged away. Examples of this are AdS5 × S5 and AdS3 × S3 × T4, where we perform the construction of different stable systems, which stability relies in its dielectric character.
ON THE ROLE OF LOW-ENERGY CP VIOLATION IN LEPTOGENESIS
Authors: BLANCHET STEVE , PÉREZ PAVEL FILEVIEZ
Published: June 2009

The link between low-energy CP violation and leptogenesis became more accessible with the understanding of flavor effects. However, a definite well-motivated model where such a link occurs was still lacking. Adjoint SU(5) is a simple grand unified theory where neutrino masses are generated through the Type I and Type III seesaw mechanisms, and the lepton asymmetry is generated by the fermionic triplet responsible for the Type III seesaw. We focus exclusively on the case of inverted hierarchy for neutrinos, and we show that successful flavored leptogenesis in this theory strongly points towards low-energy CP violation. Moreover, since the range of allowed masses for the triplet is very restricted, we find that the discovery at the LHC of new states present in the theory, together with proton decay and unification of gauge couplings, can conspire to provide a hint in favor of leptogenesis.
A QUANTUM GOLDMAN BRACKET FOR LOOPS ON SURFACES
Authors: NELSON J. E. , PICKEN R. F.
Published: June 2009

In the context of (2+1)–dimensional gravity, we use holonomies of constant connections which generate a q–deformed representation of the fundamental group to derive signed area phases which relate the quantum matrices assigned to homotopic loops. We use these features to determine a quantum Goldman bracket (commutator) for intersecting loops on surfaces, and discuss the resulting quantum geometry.
TYPE I SUPERSTRING THEORY IN THE FORM OF OPEN TYPE IIB ONE WITH APPROPRIATE CHOICE OF BOUNDARY CONDITIONS
Authors: NIKOLIĆ BOJAN , SAZDOVIĆ BRANISLAV
Published: June 2009

We improve relation between type IIB and type I superstring theory. In fact we obtain type I theory as type IIB on the solution of appropriately chosen boundary conditions. We find that type I theory, which is symmetric under world-sheet parity transformation Ω : σ → - σ, beside Ω even fields of the type IIB theory, contains squares of Ω odd fields.
TOTAL SPACE OF ABELIAN GERBES
Authors: SZAMOTULSKI MARCIN , MARCINIAK DOROTA
Published: June 2009

We present a generalization of the construction of a principal G-bundle from a one Čech cocycle to the case of higher abelian gerbes. We prove that the sheaf of local sections of the associated bundle to a higher abelian gerbe is isomorphic to the sheaf of sections of the gerbe itself. Our main result states that equivalence classes of higher abelian gerbes are in bijection with isomorphism classes of the corresponding bundles. We also present topological characterization of those bundles. In the last section, we show that the usual notion of Ehresmann connection leads to the gerbe connection for higher ℂ*-gerbes.
LINE ELEMENT IN QUANTUM GRAVITY: THE EXAMPLE OF DSR AND NONCOMMUTATIVE GEOMETRY
Authors: MARTINETTI PIERRE
Published: June 2009

We question the notion of line element in some quantum spaces that are expected to play a role in quantum gravity, namely noncommutative deformations of Minkowski spaces. We recall how the implementation of the Leibniz rule forbids to see some of the infinitesimal deformed Poincaré transformations as good candidates for Noether symmetries. Then we recall the more fundamental view on the line element proposed in noncommutative geometry, and re-interprete at this light some previous results on Connes' distance formula.
CONTROLLING THE QUANTUM ROTOR WITH A TIME-DEPENDENT MAGNETIC FLUX
Authors: SCHMIDT ALEXANDRE G. M. , MARTINS BRUNO N.
Published: June 2009

We study the possibility of controlling a quantum rotor interacting with a time-dependent external field, namely, using a continuous or a piecewise continuous (bang-bang control) magnetic flux. Using the exact eigenfunctions we show how to steer a wave-packet constructed as a superposition of these eigenstates. In the first case we show how to steer a Gaussian wave-packet (GWP) to two other positions: one of them which would not be realized if the evolution were free, and the second is the one where wave-packet revival takes place. In the piecewise approach we implement a kind of tracking control, i.e. before steering it to the final target we achieve another given GWP.
SYNCHRONIZATION OF NEURAL NETWORKS OF NEUTRAL TYPE WITH STOCHASTIC PERTURBATION
Authors: PARK JU H. , KWON O. M.
Published: June 2009

In this letter, the problem of feedback controller design to achieve synchronization for neural network of neutral type with stochastic perturbation is considered. Based on Lyapunov method and LMI (linear matrix inequality) framework, the goal of this letter is to derive an existence criterion of the controller for the synchronization between master and response networks.
STATISTICAL INTERPRETATION ON THE BROWNIAN STEPS OF KINESIN AND ITS PERFORMANCE CHARACTERISTICS
Authors: ZHANG YUE , CHEN JINCAN
Published: June 2009

Kinesin is a stepping motor that moves along microtubules in discrete steps of 8 nm and there may exist three events in kinesin movement, i.e. the forward step, the backward step and the detachment. On the basis of the data obtained in the advanced experiments and the assumption that the rates of the three stochastic reaction events are Boltzmann type, the mechanical kinetic and thermodynamic properties of the kinesin motor are investigated through a statistical method. The mean dwell time, velocity, run length, power and efficiency of the motor are calculated theoretically. The effects of the temperature and load on the performance of the motor are discussed. It is found that the temperature dependent relations of both the mean run length and the efficiency ηM are not simply linear. The results are in good agreement with those obtained in previous experimental researches.
APPLICATIONS OF THE LIE ALGEBRA gl(2)
Authors: ZHANG YUFENG , TAM HONWAH
Published: June 2009

With the help of a subalgebra of the Lie algebra gl (2) (still denoted by gl (2)), a non-isospectral evolution-equation hierarchy is obtained, whose reduction is similar to that given by Li. Employing the Lie algebra gl (2) again, we work out nonlinear evolution equations with exponential terms and produce their Bäcklund Transformation as well as some exact solutions.
THE SECOND-ORDER KdV EQUATION AND ITS SOLITON-LIKE SOLUTION
Authors: LEE CHUN-TE , LIU JINN-LIANG , LEE CHUN-CHE , KANG YAW-HONG
Published: June 2009

This paper presents both the theoretical and numerical explanations for the existence of a two-soliton solution for a second-order Korteweg-de Vries (KdV) equation. Our results show that there exists "quasi-soliton" solutions for the equation in which solitary waves almost retain their identities in a suitable physical regime after they interact, and bear a close resemblance to the pure KdV solitons.
SYNTHESIS AND ROOM TEMPERATURE FERROMAGNETIC PROPERTY OF COBALT DOPED ZINC OXIDE
Authors: WEN FENGYU
Published: June 2009

Nanocrystalline Co -doped ZnO ( Zn 1-x Co x O , x = 0.00, 0.05) powders have been successfully prepared by a microwave-assisted combustion method using Zn ( NO 3)2·6 H 2 O and Co ( NO 3)2·6 H 2 O as starting materials and urea as fuel. The as-prepared products were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). It was found that the combustion process took only a few minutes to obtain Zn 1-x Co x O powders. The field dependence of magnetization measurement at room temperature for the as-prepared Zn 0.95 Co 0.05 O powders exhibited the obvious ferromagnetic behavior.
CONTROLLING LIU SYSTEM WITH DIFFERENT METHODS
Authors: WANG MINGJUN , WANG XINGYUAN
Published: June 2009

In this paper, two different kinds of methods are adopted to control Liu system — feedback method and nonfeedback method. On the one hand, direct feedback and adaptive time-delayed feedback are taken as examples for the study of feedback control. In the direct feedback method, Liu system can be stabilized at one equilibrium point or a limit cycle surrounding its equilibrium. In the adaptive time-delayed feedback method, feedback coefficient and delay time can be adjusted adaptively to stabilize Liu system at its original unstable periodic orbit. On the other hand, periodic parametric perturbation is used to control chaos in Liu system as a typical nonfeedback method. By changing the frequency of the perturbation signal, Liu system can be guided to not only periodic motion but also hyperchaos. Numerical simulations show the effectiveness of our methods.
PHOTOLUMINESCENCE OF NON-CRYSTALLINE ALUMINA NANOWIRES SYNTHESIZED BY DIRECT ANODIZATION OF ALUMINUM
Authors: SARKAR JAYA , KHAN GOBINDA GOPAL , BASUMALLICK A.
Published: June 2009

Alumina nanowires have been synthesized by a simple electrochemical route, by tailoring the anodization process of aluminum. Two-stage anodization of pure aluminum foils were carried out in 0.3 M oxalic acid electrolyte by maintaining a constant current density of 250 A/m2 and suitably controlling the other anodization parameters: anodization voltage, bath temperature and anodization time. The fabricated alumina nanowires were investigated by field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Moreover, the X-ray diffraction (XRD) study on the prepared nanowires shows that they are non-crystalline in nature. The photoluminescence (PL) spectra of alumina nanowires exhibit two stable emission bands at 438 and 581 nm. The blue luminescence behavior of the alumina nanowires are attributed to the oxygen-deficient defect centers. PL study of alumina nanowires shows that they have potential applications in light emission devices.
Environmental Regulations and Economic Activity: Influence on Market Structure
Authors: Millimet Daniel L. , Roy Santanu , Sengupta Aditi
Published: June 2009

We survey recent developments in the theoretical and empirical literature on the economic effects of environmental regulation on various aspects of market structure including entry, exit, and size distribution of firms and market concentration.
On Dichotomous Behavior of Variational Difference Equations and Applications
Authors: Sasu Bogdan
Published: June 2009

We give new and very general characterizations for uniform exponential dichotomy of variational difference equations in terms of the admissibility of pairs of sequence spaces over ℕ with respect to an associated control system. We establish in the variational case the connections between the admissibility of certain pairs of sequence spaces over ℕ and the admissibility of the corresponding pairs of sequence spaces over ℤ. We apply our results to the study of the existence of exponential dichotomy of linear skew‐product flows.
A General Discrete Time Model of Population Dynamics in the Presence of an Infection
Authors: Izzo Giuseppe , Muroya Yoshiaki , Vecchio Antonia
Published: June 2009

We present a set of difference equations which generalizes that proposed in the work of G. Izzo and A. Vecchio (2007) and represents the discrete counterpart of a larger class of continuous model concerning the dynamics of an infection in an organism or in a host population. The limiting behavior of this new discrete model is studied and a threshold parameter playing the role of the basic reproduction number is derived.
On Some Generalized Ky Fan Minimax Inequalities
Authors: Luo Xianqiang
Published: June 2009

Some generalized Ky Fan minimax inequalities for vector-valued mappings are established by applying the classical Browder fixed point theorem and the Kakutani-Fan-Glicksberg fixed point theorem.
Numerical Estimation of Torsional Dynamic Coefficients of a Hydraulic Turbine
Authors: Karlsson Martin , Nilsson Håkan , Aidanpää Jan-Olov
Published: June 2009

The rotordynamic behavior of a hydraulic turbine is influenced by fluid‐rotor interactions at the
turbine runner. In this paper computational fluid dynamics (CFDs) are used to numerically predict
the torsional dynamic coefficients due to added polar inertia, damping, and stiffness of a Kaplan
turbine runner. The simulations are carried out for three operating conditions, one at about 35%
load, one at about 60% load (near best efficiency), and one at about 70% load.
The runner rotational speed is perturbed with a sinusoidal function with different frequencies in
order to estimate the coefficients of added polar inertia and damping. It is shown that the added
coefficients are dependent of the load and the oscillation frequency of the runner. This affect the
system′s eigenfrequencies and damping. The eigenfrequency is reduced with up to 65% compared
to the eigenfrequency of the mechanical system without the fluid interaction. The contribution to
the damping ratio varies between 30–80% depending on the load. Hence, it is important to consider
these added coefficients while carrying out dynamic analysis of the mechanical system.
Fractional Evolution Equations Governed by Coercive Differential Operators
Authors: Li Fu-Bo , Li Miao , Zheng Quan
Published: June 2009

This paper is concerned with evolution equations of fractional order Dαu(t) = Au(t); u(0) = u0, u′(0) = 0, where A is a differential operator corresponding to a coercive polynomial taking values in a sector of angle less than π and 1 < α < 2. We show that such equations are well posed in the sense that there always exists an α‐times resolvent family for the operator A.
Bulk Behavior of Ball Milled AA2124 Nanostructured Powders Reinforced with TiC
Authors: Salem Hanadi G. , El-Eskandarany Sherif , Kandil Amr , Abdul Fattah Hassan
Published: June 2009

In the current research work, a top‐down approach was employed for the refinement of a micron scale AA2124 alloy powder 40 μm in average size using high‐energy ball milling up to 60 hours. The produced nanopowders were investigated compared to the micron gas atomized powder both in the monolithic and the reinforced composite states. 1 μm powder of TiC with internal structure <100 nm was used for the reinforcement of the 2124‐Al matrices. Milling time of 36 hours produced a <100 nm nanopowders with internal structure size <20 nm. The nanopowder monolithic consolidates exhibited compressive strength of 388 MPa compared to 313 MPa for micronpowder one. Addition of TiC nanostructured powder to the nanopowder consolidated matrix resulted in increase of 130% in compressive strength compared to that produced for the microscale one. Nanopowder of Alalloys produced by mechanical milling reinforced with 10 wt% TiC is recommended for products suitable for high wear and erosion resistance applications. Peak aging increased the hardness and compressive strength of the as compacted micronpowder matrices by an average of 188% and 123%, while increased that of the nanopowder matrices by an average of 110% and 117%, respectively.
The Track of Brain Activity during the Observation of TV Commercials with the High‐Resolution EEG Technology
Authors: Astolfi Laura , Vecchiato Giovanni , De Vico Fallani Fabrizio , Salinari Serenella , Cincotti Febo , Aloise Fabio , Mattia Donatella , Marciani Maria Grazia , Bianchi Luigi , Soranzo Ramon , Babiloni Fabio
Published: June 2009

We estimate cortical activity in normal subjects during the observation of TV commercials inserted within a movie by using high‐resolution EEG techniques. The brain activity was evaluated in both time and frequency domains by solving the associate inverse problem of EEG with the use of realistic head models. In particular, we recover statistically significant information about cortical areas engaged by particular scenes inserted within the TV commercial proposed with respect to the brain activity estimated while watching a documentary. Results obtained in the population investigated suggest that the statistically significant brain activity during the observation of the TV commercial was mainly concentrated in frontoparietal cortical areas, roughly coincident with the Brodmann areas 8, 9, and 7, in the analyzed population.
Total Stability in Nonlinear Discrete Volterra Equations with Unbounded Delay
Authors: Choi Sung Kyu , Goo Yoon Hoe , Im Dong Man , Koo Namjip
Published: June 2009

We study the total stability in nonlinear discrete Volterra equations with unbounded delay, as a discrete analogue of the results for integrodifferential equations by Y. Hamaya (1990).
Hypotheses on the Role of Transforming Growth Factor-β in the Onset and Progression of Hepatocellular Carcinoma
Authors: Dooley Steven , Weng Honglei , Mertens Peter R.
Published: June 2009

Hepatocellular carcinomas (HCCs) constitute a therapeutic challenge with mostly unfavorable outcome. This may reflect our incomplete understanding of disease pathogenesis, e.g. the elucidation of tumorigenic signaling pathways. Knowledge gathered hitherto focuses on genetic alterations that result in the loss of tumor suppressor functions as well as amplification and mutation of cancer genes. Further evidence points to a decisive role of cytostatic and apoptotic functions mediated on hepatocytes by transforming growth factor (TGF)-β. These effects are critical for the control of liver mass with loss of TGF-β activities resulting in hyperproliferative disorders and cancer. This concept is based on studies that describe a bipartite role of TGF-β with tumor suppressor functions at early stages of liver damage and regeneration, whereas during cancer progression TGF-β may turn from a tumor suppressor to a tumor promoter that exacerbates invasive and metastatic behavior. Consequently and most importantly, the oncogenic potential of recent therapeutic approaches against profibrogenic TGF-β effects needs to be carefully delineated and a cancer therapy with specific targets disrupting the TGF-β signaling cascade may be envisioned. In line with this concept, we and others found overexpression of TGF-β antagonist Smad7 in the majority of HCC samples, providing a mechanism for hepatocytes to escape TGF-β-dependent growth control in the process of cancerogenesis.
Hepatocellular Carcinoma: Pathology and Liver Biopsy
Authors: Kalinski Thomas , Roessner Albert
Published: June 2009

Hepatocellular carcinoma (HCC) is the most frequent malignant tumor of the liver. The diagnosis of HCC depends on the measurement of serum α-fetoprotein levels and imaging techniques. Liver biopsy is recommended in uncertain cases. We review the morphological characteristics of HCC and their differential diagnoses including other liver tumors and metastases. We further specify problems and pitfalls in the differential diagnosis and discuss limitations of liver biopsies in the diagnosis of HCC.
Transabdominal Ultrasound with Echoenhancement by Contrast Media in the Diagnosis of Hepatocellular Carcinoma
Authors: Schacherer Doris , Girlich Christiane , Jung Michael E. , Wiest Reiner , Schölmerich Juergen
Published: June 2009

According to the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD), ultrasound (US) is the recommended tool for surveillance of patients at risk of developing hepatocellular carcinoma (HCC). Larger HCCs can be diagnosed with a high accuracy by conventional US. However, the differentiation of smaller malignant lesions in cirrhotic livers can be improved by contrast-enhanced ultrasound (CEUS). Second-generation contrast agents consisting of microbubbles enable us to visualize specific tumor vascularization patterns. With CEUS, it is not only possible to detect and characterize HCC nodules, but to control the effects of ablation techniques of HCC as well, evaluating the former lesion with respect to complete necrosis or residual viable tumor. Limitations of CEUS are its inability to characterize lesions distant to the applicator. Moreover, so far the use of contrast agents in US did not result in increased sensitivity in the detection of small HCCs (<1 cm). Thus, there is currently no indication to use contrast agents to increase the detection rate of HCC in patients undergoing US surveillance.
Imaging of Hepatocellular Carcinoma by Computed Tomography and Magnetic Resonance Imaging: State of the Art
Authors: Zech Christoph J. , Reiser Maximilian F. , Herrmann Karin A.
Published: June 2009

Hepatocellular carcinoma (HCC) is a very frequent tumor worldwide. Its incidence is linked to the distribution of liver cirrhosis and viral hepatitis, which are the main risk factors for the development of HCC. For the evaluation of the cirrhotic liver and for the diagnosis of HCC, multidetector computed tomography (MDCT) proved to be a robust and reliable tool. In MDCT the diagnosis of HCC can be made based on neovascularization with increased arterial and decreased portal venous supply. With modern magnetic resonance imaging (MRI), spatial resolution and robustness increased dramatically. Beside the evaluation of neovascularization by means of gadolinium-enhanced early dynamic MRI, the main advantages of MRI are additional information on tissue composition and liver-specific function. With diffusion-weighted imaging or plain T1- and T2-weighted sequences, different tissue elements like fat, hemorrhage, glycogen, edema and cellular density can be evaluated. Liver-specific contrast agents give insight into the Kupffer cell density or the hepatocellular function. The integration of all these parts into the MR examination allows for a very high detection rate for overt HCC nowadays, although very small HCCs are still a challenge. Moreover, insight into the different stages of hepatocarcinogenesis can be possible with MRI. Despite its limited availability in some countries, it has to be rendered to be the modality of choice for the distinct evaluation of the cirrhotic liver.
HCC Diagnosis with Liver-Specific MRI – Close to Histopathology
Authors: Bartolozzi Carlo , Battaglia Valentina , Bozzi Elena
Published: June 2009

Thanks to the sensible and continuous improvements achieved, magnetic resonance imaging (MRI) can nowadays be considered the most accurate modality to image the liver. Moreover, the technique is the only one able to provide at the same time information about intracellular and vascular changes occurring in parenchymas. For these reasons, MRI plays a major role in the surveillance and follow-up of patients with cirrhosis. If a baseline MR study investigates the progressive alteration of lesion architecture, grading, stromal component, as well as intracellular content of fat, glycogen, or metal ions, thus leading to a frequent confident diagnosis of lesion nature, a dynamic study provides additional information about lesion vascular enhancement, which may represent the only clue for the differential diagnosis between premalignant and malignant lesions. In addition, the introduction of hepatobiliary contrast agents has further implemented the diagnostic confidence of the technique, permitting to explore the so-called grey area in which significant histological changes are already present without an evident arterial supply of the nodule. Although in the evaluation of liver pathologies MRI is mainly applied in the study of cirrhosis, the technique also plays a fundamental role in the assessment of other primitive liver malignancies, such as fibrolamellar carcinoma or cholangiocarcinoma. In these cases in particular, MRI is required to pose a differential diagnosis with other liver malignancies (such as metastases), and, once the nature of the neoplasm is assessed, to give an accurate locoregional staging.
Clinical Staging of Hepatocellular Carcinoma
Authors: Meier Volker , Ramadori Giuliano
Published: June 2009

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. The resistance of HCC to existing treatments and the lack of biomarkers for early detection make it one of most hard-to-treat cancers. Surgical tumor resection, including liver transplantation, remains the only curative modality for HCC. Several clinical prognostic models have been developed for the staging of patients with HCC, but there is no general consensus which is the most reliable. There are restrictions in the use of these prognostic scores, because most scores were not validated in different countries and the HCCs differ in their biological behavior. A further problem is the heterogeneity of patients with HCC (with or without cirrhosis, compensated or decompensated cirrhosis and treated or nontreated patients); many studies combine patients with and without cirrhosis and patients with compensated and decompensated cirrhosis. The clinical efficiency of these scores is therefore limited to patients with HCC. Nowadays, DNA microarray technology has revolutionized the understanding of the molecular basis of HCC; therefore, many studies aimed to discover biomarkers for cancer staging, for prediction of recurrence, for prognosis, and for treatment selection. Most of the studies are too small for the development of predictors and at the moment microarray technology is too expensive for daily clinical use. Therefore, DNA microarray technology is at the moment not an established method in the prediction of the prognosis of patients with HCC. Future prognostic studies should include different predictors and should be performed in selected patient populations to determine whether specific prognostic indicators are more relevant at different stages of liver disease.
Treatment of Hepatocellular Carcinoma by Radioembolization Using 90Y Microspheres
Authors: Sangro Bruno , Bilbao Jose I. , Iñarrairaegui Mercedes , Rodriguez Macarena , Garrastachu Puy , Martinez-Cuesta Antonio
Published: June 2009

The use of external beam radiation therapy for primary treatment of hepatocellular carcinoma (HCC) has been limited by the low radiation tolerance of the non-tumoral liver. However, technical advances allowing partial liver volume external irradiation have resulted in consistently high response rates. Internal radiation therapy, also called 90Y radioembolization (90Y-RE), consists in delivering implantable microspheres labeled with 90Y into the arteries that feed liver tumors in order to provide a high dose of radiation to tumor nodules irrespective of their number, size and location, while preserving the non-tumoral liver tissue from receiving a harmful level of radiation. Among patients with HCC, 90Y-RE is used for those that have a preserved liver function and unresectable tumors that cannot be treated with percutaneous ablation. Although 90Y-RE is by and large well tolerated, it may produce relevant toxic effects as a result of radiation of non-target organs including cholecystitis, gastrointestinal ulceration, pneumonitis, and most importantly, liver toxicity. A significant effect on tumor growth in the treated lesions is consistently observed with disease control rates in excess of 80%. Also, 90Y-RE may allow downstaging large or multiple lesions to radical treatments with curative intent. When compared with the survival of HCC patients in advanced stage either not treated or treated with ineffective systemic agents, survival after 90Y-RE is encouraging and warrants future clinical trials. Clinical research in combining the cytotoxic effect of 90Y with the cytostatic mechanism of targeted therapies is currently in progress and will provide valuable safety and toxicity data that may translate into improved clinical outcome and overall survival.
Image-Guided Interstitial High-Dose-Rate Brachytherapy in Hepatocellular Carcinoma
Authors: Mohnike Konrad , Wieners Gero , Pech Maciej , Seidensticker Max , Rühl Ricarda , Lopez-Haenninen Enrique , Ricke Jens
Published: June 2009

New interventional options especially for patients with HCC and BCLC scores B and C give rise to disputes about the optimal therapeutic management. CT-guided brachytherapy complements established interventional techniques like RFA and TACE since it may also be used successfully in tumors much greater than 5 cm in diameter. In addition, unlike thermal ablation, the brachytherapy technique may be applied in tumors located nearby risk structures such as liver hilum or gallbladder and it is independent of cooling effects such as through large blood vessels or strong tumor perfusion. Depending on tumor size, geometry and visibility, MRI or CT guidance may be used. 15 Gy minimal target dose can be applied safely in a single or – in case of very large tumors – a sequential approach targeting different tumor portions. Local recurrence rates will be very low, and the rate of complications is moderate despite the fact that most patients present with underlying cirrhosis and related comorbidities. Preliminary data suggest a positive impact on overall survival. Randomized controlled trials are on their way to assess combination schemes with systemic treatments such as sorafenib.
Systemic Therapies in Hepatocellular Carcinoma
Authors: Wörns Marcus Alexander , Weinmann Arndt , Schuchmann Marcus , Galle Peter Robert
Published: June 2009

Hepatocellular carcinoma (HCC) is one of the most common and lethal malignant tumors worldwide in the human population. Due to late diagnosis and/or advanced underlying liver cirrhosis, only limited treatment options with marginal clinical benefit are available in up to 70% of patients. During the last decades, no effective conventional cytotoxic systemic therapy was available contributing to the dismal prognosis in patients with advanced disease. However, a better knowledge of molecular hepatocarcinogenesis provides today the opportunity for targeted therapy. Positive data from the pivotal phase III SHARP trial assessing the efficacy and safety of the multikinase inhibitor sorafenib broadened the horizon for patients with advanced disease. After years of therapeutic nihilism, sorafenib was the first agent to demonstrate a statistically significant improvement in overall survival for patients with advanced HCC. This article reviews the historical perspective of systemic therapy in HCC and provides a brief overview of molecular hepatocarcinogenesis and potential targets in HCC. Most promising molecular targeted agents tested within clinical trials in advanced HCC are summarized, with a special attention to sorafenib, sunitinib, bevacizumab, and erlotinib.