bluuebunny/crossref_metadata_2025 huggingface dataset:
C3P0 MODEL FOR CHARMED MESONS DECAY
Authors: DA SILVA D. T. , DE QUADROS J. N. , DA SILVA M. L. L. , VASCONCELLOS C. A. Z. , HADJIMICHEF D.
Published: August 2010

The successful mapping technique, Fock–Tani formalism, has produced a corrected 3P0 model ( C 3P0 model), which retains the basic aspects of the 3P0 predictions with the inclusion of bound-state corrections. The model is applied for charmed mesons decay. The amplitude and its respective decay rates are evaluated.
RADIAL OSCILLATIONS OF COLOR SUPERCONDUCTING QUARK STARS
Authors: VASQUEZ FLORES C. , LUGONES G.
Published: August 2010

In this work, we investigate the effect of color superconductivity in adiabatic radial oscillations of stars consisting of quark matter. We calculate the equilibrium configurations by integrating the Tolman–Oppenheimer–Volkoff equations of relativistic stellar structure and then we integrate the equations of relativistic radial oscillations to determine the oscillation modes.
RESULTS FROM THE TELESCOPE ARRAY EXPERIMENT
Authors:   For the Telescope Array Collaboration, SAGAWA H.
Published: August 2010

The Telescope Array (TA) is the largest hybrid detector in the northern hemisphere, which consists of an array of surface detectors (SD) and fluorescence detectors (FD), to explore the origin of ultra-high energy cosmic rays (UHECR) by measuring energy, arrival direction, mass composition, and other characteristics of UHECRs. Here we present the status and preliminary results based on the first data set of the experiment.
EVOLUTION OF SUPERMASSIVE BLACK HOLES FROM COSMOLOGICAL SIMULATIONS
Authors: FILLOUX C. , DURIER F. , PACHECO J. A. F. , SILK J.
Published: August 2010

The correlations between the mass of supermassive black holes and the properties of their host galaxies are investigated through cosmological simulations. Black holes grow from seeds of 100 M⊙ are inserted into density peaks presented in the redshift range 12–15. Seeds grow essentially by accreting matter from a nuclear disk and also by coalescences resulting from merger episodes. At z = 0, our simulations reproduce the black hole mass function and the correlations of the black hole mass, both with stellar velocity dispersion and host dark halo mass. Moreover, the evolution of the black hole mass density derived from the present simulations agrees with that derived from the bolometric luminosity of quasars, indicating that the average accretion history of seeds is adequately reproduced. However, our simulations are unable to form black holes with masses above 109 M⊙ at z ~ 6, whose existence is inferred from the bright quasars detected by the Sloan survey in this redshift range.
ON THE CONFINED–DECONFINED PHASE TRANSITION IN NUCLEAR MATTER AND NEUTRON STARS
Authors: BURIGO L. N. , BODMANN B. E. J. , JACOBSEN R. B. , VASCONCELLOS C. A. Z. , FERNÁNDEZ F.
Published: August 2010

In this work we focus our study on the transition from hadron to deconfined quark matter, and we shall assume that the phase transition is first-order with two independent components, which are related to the local conservation of baryon number and the global conservation of electric charge. Relativistic effective theories are employed to describe the hadron and quark phase. Two different hadronic models are adopted: an adjustable model and the well known Boguta–Bodmer model. Deconfined phase is described employing the MIT bag model. Previous studies showed that the choice of the hadronic model as well as its parameters (including nucleon effective mass and hyperonic coupling schemes) have influence on phase transition properties. Our aim is to analyze if such results on phase transition play an important role on the modeling of neutron stars. To carry out such analysis, the Tolman–Oppenheimer–Volkoff equations are employed to determine the maximum mass for each combination of hadronic model and parameters.
NON-LOCAL CHIRAL QUARK MODELS WITH POLYAKOV LOOP AT FINITE TEMPERATURE AND CHEMICAL POTENTIAL
Authors: CONTRERA G. A. , ORSARIA M. , SCOCCOLA N. N.
Published: August 2010

We analyze the chiral restoration and deconfinement transitions in the framework of a non-local chiral quark model which includes terms leading to the quark wave function renormalization, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. Non-local interactions are described by considering both a set of exponential form factors, and a set of form factors obtained from a fit to the mass and renormalization functions obtained in lattice calculations.
FIXED-POINT INTERACTIONS AND RENORMALIZATION GROUP INVARIANCE IN THE TWO-NUCLEON SYSTEM
Authors: TIMÓTEO V. S. , SZPIGEL S. , DURÃES F. O.
Published: August 2010

We study the fixed-point interactions and the renormalization group invariance for an effective nucleon–nucleon (NN) interaction in the leading-order (LO) chiral effective field theory (ChEFT) renormalized within the framework of the subtracted kernel method (SKM) approach. By solving a nonrelativistic Callan–Symanzik (NRCS) equation we show how the driving term evolves with the subtraction scale to keep the T-matrix invariant. We calculate the fixed-point interaction from the driving term and compare the results obtained with and without its evolution through the NRCS equation.
GENERATING ANISOTROPIC FLUIDS FROM VACUUM ERNST EQUATIONS
Authors: VIAGGIU STEFANO
Published: August 2010

Starting with any stationary axisymmetric vacuum metric, we build anisotropic fluids. With the help of the Ernst method, the basic equations are derived together with the expression for the energy–momentum tensor and with the equation of state compatible with the field equations. The method is presented by using different coordinate systems: the cylindrical coordinates ρ, z and the oblate spheroidal ones. A class of interior solutions matching with stationary axisymmetric asymptotically flat vacuum solutions is found in oblate spheroidal coordinates. The solutions presented satisfy the three energy conditions.
AGEGRAPHIC DARK ENERGY MODEL IN THE NON-FLAT UNIVERSE: STATEFINDER DIAGNOSTIC AND w–w′ ANALYSIS
Authors: MALEKJANI M. , KHODAM-MOHAMMADI A.
Published: August 2010

We study the interacting agegraphic dark energy (ADE) model in the non-flat universe by means of the statefinder diagnostic and an w–w′ analysis. First, the evolution of EoS parameter (wd) and deceleration parameter (q) are calculated in terms of scale-factor for interacting ADE models in the non-flat universe. The dependency of wd on the ADE model parameters n and α in different spatial curvatures is investigated. We show that the evolution of q is dependent on the type of spatial curvature, besides dependening on parameters n and α. The accelerated expansion takes place sooner in the open universe and latter in the closed universe as compared with the flat universe. Then, we plot the evolutionary trajectories of the interacting ADE models for different values of the parameters n and α, as well as for different contributions of spatial curvature, in the plane of statefinder parameters. In addition to the statefinder, we also investigate the ADE model in the non-flat universe with w–w′ analysis.
TUBE FORMULAS FOR GRAPH-DIRECTED FRACTALS
Authors: DEMÍR BÜNYAMIN , DENÍZ ALI , KOÇAK ŞAHIN , ÜREYEN A. ERSIN
Published: August 2010

Lapidus and Pearse proved recently an interesting formula about the volume of tubular neighborhoods of fractal sprays, including the self-similar fractals. We consider the graph-directed fractals in the sense of graph self-similarity of Mauldin-Williams within this framework of Lapidus-Pearse. Extending the notion of complex dimensions to the graph-directed fractals we compute the volumes of tubular neighborhoods of their associated tilings and give a simplified and pointwise proof of a version of Lapidus-Pearse formula, which can be applied to both self-similar and graph-directed fractals.
MULTIRESOLUTION CONTROL OF CURVES AND SURFACES WITH A SELF-SIMILAR MODEL
Authors: HNAIDI HOUSSAM , GUÉRIN ERIC , AKKOUCHE SAMIR
Published: August 2010

This paper presents two self-similar models that allow the control of curves and surfaces. The first model is based on IFS (Iterated Function Systems) theory and the second on subdivision curve and surface theory. Both of these methods employ the detail concept as in the wavelet transform, and allow the multiresolution control of objects with control points at any resolution level.

In the first model, the detail is inserted independently of control points, requiring it to be rotated when applying deformations. In contrast, the second method describes details relative to control points, allowing free control point deformations.

Modeling examples of curves and surfaces are presented, showing manipulation facilities of the models.
MONOFRACTAL AND MULTIFRACTAL SCALING ANALYSIS OF pH TIME SERIES FROM DONGTING LAKE INLET AND OUTLET
Authors: HUANG ZHENG-WEN , LIU CHUN-QIONG , SHI KAI , ZHANG BIN
Published: August 2010

The water pH series from Dongting Lake Inlet and Outlet in China are analyzed by detrended fluctuation analysis (DFA), spectral analysis and multifractal methods. The results show that these pH series are characterized by long-term memory, 1/f noise and multifractal scaling, and these characteristics have obvious difference between the Lake Inlet and Outlet. The comparison results show that monofractal (DFA exponent) and multifractal (Δα, Δf, B) parameters can be quantitative dynamical indexes reflecting the capability of anti-acidification of Dongting Lake. Furthermore, we investigate the frequency-size distribution of pH series from Dongting Lake Inlet and Outlet. Our findings suggest that water pH is an example of a self-organized criticality (SOC) process. Based on concept of self-organized ctiticality, we analysis the cause that different scale-free power-law behavior between pH series from Dongting Lake Inlet and Outlet. This work can be helpful to improvement of modeling of lake water quality.
ARNOLD TONGUES AND FEIGENBAUM EXPONENTS OF THE RATIONAL MAPPING FOR Q-STATE POTTS MODEL ON RECURSIVE LATTICE: Q < 2
Authors: ANANIKYAN L. N. , ANANIKIAN N. S. , CHAKHMAKHCHYAN L. A.
Published: August 2010

We considered Q-state Potts model on Bethe lattice in presence of external magnetic field for Q < 2 by means of recursion relation technique. This allows to study the phase transition mechanism in terms of the obtained one dimensional rational mapping. The convergence of Feigenabaum α and δ exponents for the aforementioned mapping is investigated for the period doubling and three cyclic window. We regarded the Lyapunov exponent as an order parameter for the characterization of the model and discussed its dependence on temperature and magnetic field. Arnold tongues analogs with winding numbers w = 1/2, w = 2/4 and w = 1/3 (in the three cyclic window) are constructed for Q < 2. The critical temperatures of the model are discussed and their dependence on Q is investigated. We also proposed an approximate method for constructing Arnold tongues via Feigenbaum δ exponent.
A NEW FAST TECHNIQUE FOR FINGERPRINT IDENTIFICATION WITH FRACTAL AND CHAOS GAME THEORY
Authors: JAMPOUR MAHDI , YAGHOOBI MAHDI , ASHOURZADEH MARYAM , SOLEIMANI ADEL
Published: August 2010

Fingerprints are one of the simplest and most reliable human biometric features for identification. Geometry of the fingerprint is fractal and we can classify a fingerprint database with fractal dimension, but one can't identify a fingerprint with fractal dimension uniquely. In this paper we present a new approach for identifying fingerprint uniquely; for this purpose a new fractal is initially made from a fingerprint by using Fractal theory and Chaos Game theory. While making the new fractal, five parameters that can be used in identification process can be achieved. Finally a fractal is made for each fingerprint, and then by analyzing the new fractal and parameters obtained by Chaos Game, fingerprint identification can be performed. We called this method Fingerprint Fractal Identification System (FFIS). The presented method besides having features of fractals such as stability against turning, magnifying, deleting a part of image, etc. also has a desirable speed.
SEMISIMPLE TORSION IN GROUPS OF FINITE MORLEY RANK
Authors: BURDGES JEFFREY , CHERLIN GREGORY
Published: August 2010

We prove several results about groups of finite Morley rank without unipotent p-torsion: p-torsion always occurs inside tori, Sylow p-subgroups are conjugate, and p is not the minimal prime divisor of our approximation to the "Weyl group". These results are quickly finding extensive applications within the classification project.
ON LINEARLY ORDERED STRUCTURES OF FINITE RANK
Authors: ONSHUUS ALF , STEINHORN CHARLES
Published: August 2010

O-minimal structures have long been thought to occupy the base of a hierarchy of ordered structures, in analogy with the role that strongly minimal structures play with respect to stable theories. This is the first in an anticipated series of papers whose aim is the development of model theory for ordered structures of rank greater than one. A class of ordered structures to which a notion of finite rank can be assigned, the decomposable structures, is introduced here. These include all ordered structures definable (as subsets of n-tuples of the universe) in o-minimal structures. The principal result in this paper, Theorem 5.1, asserts roughly that a decomposable structure [Formula: see text] can be partitioned into finitely many definable subsets such that on each set the restriction of < is a "twisted lexicographic" order. As a consequence (Corollary 5.1), for all n and linear orders ≺ definable on a subset X ⊆ Mnin an o-minimal structure [Formula: see text], there is a definable partition of X such that the restriction of ≺ to each set in the partition is "lexicographic".
ON ASYMPTOTICALLY OPTIMAL TOWERS OVER QUADRATIC FIELDS RELATED TO GAUSS HYPERGEOMETRIC FUNCTIONS
Authors: HASEGAWA TAKEHIRO
Published: August 2010

We define two asymptotically optimal towers over quadratic fields, and give the explicit descriptions of the ramification loci and the sets of places splitting completely, which relate to the elliptic modular curves X0(4n) and X0(3n), respectively. Moreover, in the last section, we determine completely the modularity of a tower given by Maharaj and Wulftange in [18].
A FINITENESS PROPERTY FOR PREPERIODIC POINTS OF CHEBYSHEV POLYNOMIALS
Authors: IH SU-ION , TUCKER THOMAS J.
Published: August 2010

Let K be a number field with algebraic closure [Formula: see text], let S be a finite set of places of K containing the Archimedean places, and let φ be a Chebyshev polynomial. We prove that if [Formula: see text] is not preperiodic, then there are only finitely many preperiodic points [Formula: see text] which are S-integral with respect to α.
QUADRATIC RECURRENCES WITH A POSITIVE DENSITY OF PRIME DIVISORS
Authors: GOTTESMAN RICHARD , TANG KWOKFUNG
Published: August 2010

For f(x) ∈ ℤ[x] and a ∈ ℤ, we let fn(x) be the nth iterate of f(x), P(f, a) = {p prime : p|fn(a) for some n}, and D(P(f, a)) denote the natural density of P(f, a) within the set of primes. A conjecture of Jones [5] indicates that D(P(f, a)) = 0 for most quadratic f. In this paper, we find an exceptional family of (f, a) such that D(P(f, a)) > 0 by considering ft(x) = (x + t)2 - 2 - t and at = ft(0) for t ∈ ℤ. We prove that if t is not of the form ±M2 ± 2 or ±2M2 ± 2, then D(P(ft, at)) = ⅓. We also determine D(P(ft, at)) in some cases when the density is not equal to ⅓. Our results suggest a connection between the arithmetic dynamics of the conjugates of x2 and the conjugates of x2 - 2.
ON THE FIELD INTERSECTION PROBLEM OF SOLVABLE QUINTIC GENERIC POLYNOMIALS
Authors: HOSHI AKINARI , MIYAKE KATSUYA
Published: August 2010

We study a general method of the field intersection problem of generic polynomials over an arbitrary field k via formal Tschirnhausen transformation. In the case of solvable quintic, we give an explicit answer to the problem by using multi-resolvent polynomials.
EICHLER COHOMOLOGY FOR GENERALIZED MODULAR FORMS II
Authors: KNOPP MARVIN , RAJI WISSAM
Published: August 2010

We derive further results on Eichler cohomology of generalized modular forms of arbitrary real weight.
新加坡早期的潮州人与福建人：
Authors: 颜清湟
Published: August 2010

透过权力结构和权力关系的比较研究，新加坡早期华人社会的朦胧图景将得以廓清。本文选择比较潮州人和福建人这两个最大的华人方言群，企图解释华人社会的内部张力。首先检阅这两个社群的形成与结构，然后评析他们如何组织和运作。本文确认了三种权力：社会权力、非正式政治权力、强制权力。社会权力在权力结构里非常重要。社会权力的掌控取决于对方言和宗亲会馆的控制，而这种控制的基础在于经济权力。早期潮州社群的权力关系并不均衡，由某个单一强势家族控制，而早期福建社群的权力关系则比较开放和平衡，但也更为复杂。
Reduced baroreflex sensitivity and pulmonary dysfunction in alcoholic cirrhosis: effect of hyperoxia
Authors: Møller Søren , Iversen Jens S. , Krag Aleksander , Bie Peter , Kjær Andreas , Bendtsen Flemming
Published: August 2010

Patients with cirrhosis exhibit impaired regulation of the arterial blood pressure, reduced baroreflex sensitivity (BRS), and prolonged QT interval. In addition, a considerable number of patients have a pulmonary dysfunction with hypoxemia, impaired lung diffusing capacity (DlCO), and presence of hepatopulmonary syndrome (HPS). BRS is reduced at exposure to chronic hypoxia such as during sojourn in high altitudes. In this study, we assessed the relation of BRS to pulmonary dysfunction and cardiovascular characteristics and the effects of hyperoxia. Forty-three patients with cirrhosis and 12 healthy matched controls underwent hemodynamic and pulmonary investigations. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. A 100% oxygen test was performed with the assessment of arterial oxygen tensions (PaO2) and alveolar-arterial oxygen gradient. Baseline BRS was significantly reduced in the cirrhotic patients compared with the controls (4.7 ± 0.8 vs. 10.3 ± 2.0 ms/mmHg; P < 0.001). The frequency-corrected QT interval was significantly prolonged in the cirrhotic patients ( P < 0.05). There was no significant difference in BRS according to presence of HPS, PaO2, DlCO, or Child-Turcotte score, but BRS correlated with metabolic and hemodynamic characteristics. After 100% oxygen inhalation, BRS and the QT interval remained unchanged in the cirrhotic patients. In conclusion, BRS is significantly reduced in patients with cirrhosis compared with controls, but it is unrelated to the degree of pulmonary dysfunction and portal hypertension. Acute hyperoxia does not significantly revert the low BRS or the prolonged QT interval in cirrhosis.
Human-derived probiotic Lactobacillus reuteri strains differentially reduce intestinal inflammation
Authors: Liu Yuying , Fatheree Nicole Y. , Mangalat Nisha , Rhoads Jon Marc
Published: August 2010

Lactobacillus reuteri ( L. reuteri ) is a probiotic that inhibits the severity of enteric infections and modulates the immune system. Human-derived L. reuteri strains DSM17938, ATCC PTA4659, ATCC PTA 5289, and ATCC PTA 6475 have demonstrated strain-specific immunomodulation in cultured monocytoid cells, but information about how these strains affect inflammation in intestinal epithelium is limited. We determined the effects of the four different L. reuteri strains on lipopolysaccharide (LPS)-induced inflammation in small intestinal epithelial cells and in the ileum of newborn rats. IPEC-J2 cells (derived from the jejunal epithelium of a neonatal piglet) and IEC-6 cells (derived from the rat crypt) were treated with L. reuteri . Newborn rat pups were gavaged cow milk formula supplemented with L. reuteri strains in the presence or absence of LPS. Protein and mRNA levels of cytokines and histological changes were measured. We demonstrate that even though one L. reuteri strain (DSM 17938) did not inhibit LPS-induced IL-8 production in cultured intestinal cells, all strains significantly reduced intestinal mucosal levels of KC/GRO (∼IL-8) and IFN-γ when newborn rat pups were fed formula containing LPS ± L. reuteri . Intestinal histological damage produced by LPS plus cow milk formula was also significantly reduced by all four strains. Cow milk formula feeding (without LPS) produced mild gut inflammation, evidenced by elevated mucosal IFN-γ and IL-13 levels, a process that could be suppressed by strain 17938. Other cytokines and chemokines were variably affected by the different strains, and there was no toxic effect of L. reuteri on intestinal cells or mucosa. In conclusion, L. reuteri strains differentially modulate LPS-induced inflammation. Probiotic interactions with both epithelial and nonepithelial cells in vivo must be instrumental in modulating intrinsic anti-inflammatory effects in the intestine. We suggest that the terms anti- and proinflammatory be used only to describe the effects of a probiotic in the living host.
Apical sodium-dependent bile acid transporter upregulation is associated with necrotizing enterocolitis
Authors: Halpern Melissa D. , Weitkamp Jörn-Hendrik , Mount Patrick Sarah K. , Dobrenen Holly J. , Khailova Ludmila , Correa Hernan , Dvorak Bohuslav
Published: August 2010

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of premature infants. Previously, we showed that luminal bile acids (BAs) are increased and correlated with disease development and that the apical sodium-dependent BA transporter (ASBT), which transports BAs from the ileal lumen into enterocytes, is upregulated in rats with NEC. We hypothesized that intraenterocyte, rather than luminal, BAs are associated with NEC and that upregulation of ASBT may be a mechanism by which this occurs. Neonatal rats with or without the ASBT inhibitor SC-435, mice in which ASBT was knocked out, and mice that overproduce BAs were subjected to the NEC protocol. Disease development, ASBT, and the farnesoid X receptor protein, along with luminal and intraenterocyte BA levels, were assessed. In addition, ileal sections from premature infants with and without NEC were examined for ASBT via immunohistology and real-time PCR. When BAs were not transported into enterocytes (rats given SC-435 and ASBT knockout mice), severity and incidence of NEC were reduced. In contrast, in mice that overproduce BAs, ASBT was elevated, intraenterocyte BAs were increased, and disease development was increased. ASBT staining was more intense on the apical membrane of ileal enterocytes from premature infants with NEC than premature infants with non-NEC diagnoses. In addition, ASBT mRNA levels were significantly higher in infants with NEC. These data show that accumulation of intraenterocyte BAs contributes to disease development, elevated ASBT increases disease severity in experimental models of NEC, and ASBT is elevated in human NEC. These data confirm that BAs and upregulation of ASBT play a crucial role in NEC pathogenesis and suggest that inhibition of ASBT could be utilized as a therapeutic modality against this disease.
Regional differences of the effects of acetylcholine in the human gastric circular muscle
Authors: Sinn Dong Hyun , Min Byung-Hoon , Ko Eun-ju , Lee Ji Yeon , Kim Jae J. , Rhee Jong Chul , Kim Sung , Ward Sean M. , Rhee Poong-Lyul
Published: August 2010

The motor functions of the stomach have traditionally been regarded to have regional differences. However, to date there have been only a few data investigating whether such regional differences in motor function exist in the human stomach. The aims of the present study were to examine the spontaneous activity and responses to acetylcholine in the anatomically defined regions of human stomach. Human gastric circular muscle tissues from fundus, corpus, and antrum were obtained from 25 patients (14 men, 11 women with a mean age of 55.2 yr; 36–74 yr) undergoing gastrectomy for gastric cancers. Isometric force measurements were performed by using muscle strips from the different regions of the human stomach under basal conditions and in response to the exogenous application of acetylcholine. Spontaneous phasic contractions were observed in all human gastric smooth muscles. However, the responses to acetylcholine displayed regional differences. In the gastric antrum, there was a dose-dependent increase in the peak contraction, contractile frequency, and amplitude of contraction after acetylcholine exposure (up to 1 μM). However, there was no significant change in the basal tone. In the corpus and fundus, acetylcholine induced a dose-dependent increase in the peak contraction and basal tone. However, there was no significant change in the contractile frequency or amplitude of contraction. In conclusion, the response of human gastric circular muscle to acetylcholine displayed regional differences between the antrum and the corpus and fundus. This finding suggested the presence of distinct functional regions in human stomach.
Quantitative assessment of lung microstructure in healthy mice using an MR-based 3He lung morphometry technique
Authors: Osmanagic E. , Sukstanskii A. L. , Quirk J. D. , Woods J. C. , Pierce R. A. , Conradi M. S. , Weibel E. R. , Yablonskiy D. A.
Published: August 2010

The recently developed technique of lung morphometry using hyperpolarized 3He diffusion magnetic resonance (MR) (Yablonskiy DA, Sukstanskii AL, Woods JC, Gierada DS, Quirk JD, Hogg JC, Cooper JD, Conradi MS. J Appl Physiol 107: 1258–1265, 2009) permits in vivo study of lung microstructure at the alveolar level. Originally proposed for human lungs, it also has the potential to study small animals. The technique relies on theoretical developments in the area of gas diffusion in lungs linking the diffusion attenuated MR signal to the lung microstructure. To adapt this technique to small animals, certain modifications in MR protocol and data analysis are required, reflecting the smaller size of mouse alveoli and acinar airways. This is the subject of the present paper. Herein, we established empirical relationships relating diffusion measurements to geometrical parameters of lung acinar airways with dimensions typical for mice and rats by using simulations of diffusion in the airways. We have also adjusted the MR protocol to acquire data with much shorter diffusion times compared with humans to accommodate the substantially smaller acinar airway length. We apply this technique to study mouse lungs ex vivo. Our MR-based measurements yield mean values of lung surface-to-volume ratio of 670 cm−1, alveolar density of 3,200 per mm3, alveolar depth of 55 μm, and mean chord length of 62 μm, all consistent with published data obtained histologically in mice by unbiased methods. The proposed technique can be used for in vivo experiments, opening a door for longitudinal studies of lung morphometry in mice and other small animals.
SCH 602539, a Protease-Activated Receptor-1 Antagonist, Inhibits Thrombosis Alone and in Combination With Cangrelor in a Folts Model of Arterial Thrombosis in Cynomolgus Monkeys
Authors: Chintala Madhu , Strony John , Yang Bo , Kurowski Stan , Li Qiu
Published: August 2010

Objective—

To determine the antithrombotic effects of SCH 602539, an analog of the selective protease-activated receptor (PAR)-1 antagonist vorapaxar (formerly SCH 530348) currently in advanced clinical development, and the P2Y
12
ADP receptor antagonist cangrelor, alone and in combination.

Methods and Results—

Multiple platelet activation pathways contribute to thrombosis. The effects of SCH 602539 and cangrelor alone and in combination on cyclic flow reductions were evaluated in a Folts model of thrombosis in cynomolgus monkeys. The effects of these treatments on ex vivo platelet aggregation and coagulation parameters were also monitored. Dose-dependent inhibition of cyclic flow reductions was observed after treatment with SCH 602539 alone and cangrelor alone (
P
<0.05 versus vehicle for the 2 highest concentrations of each agent). The combination of SCH 602539 and cangrelor was associated with synergistic antithrombotic effects (
P
<0.05 versus vehicle for all combinations tested). The 2 highest doses of SCH 602539 inhibited platelet aggregation in response to PAR-1–selective high-affinity thrombin receptor agonist peptide by greater than 80% but did not affect platelet aggregation induced by other agonists; also, they did not affect any coagulation parameters.

Conclusion—

The combined inhibition of the PAR-1 and the P2Y
12
ADP platelet activation pathways had synergistic antithrombotic and antiplatelet effects. The addition of a PAR-1 antagonist to a P2Y
12
ADP receptor antagonist may provide incremental clinical benefits in patients with atherothrombotic disease, both in short- and long-term settings. These hypotheses need to be tested clinically.
The Risk of Deep Venous Thrombosis Associated With Injectable Depot–Medroxyprogesterone Acetate Contraceptives or a Levonorgestrel Intrauterine Device
Authors: van Hylckama Vlieg Astrid , Helmerhorst Frans M. , Rosendaal Frits R.
Published: August 2010

Objective—

To assess the risk of venous thrombosis associated with nonoral contraceptives (ie, injectable depot–medroxyprogesterone acetate contraceptives, hormone [levonorgestrel]–releasing intrauterine devices, a contraceptive patch, or a contraceptive implant).

Methods and Results—

Analyses were performed in the Multiple Environmental and Genetic Assessment study, a large case-control study on risk factors for venous thrombosis. For the current analyses, we selected premenopausal women, aged 18 to 50 years, who were not pregnant nor within 4 weeks postpartum and were not using oral contraceptives; 446 patients and 1146 controls were included. Injectable depot–medroxyprogesterone acetate contraceptives were associated with a 3.6-fold (95% CI, 1.8- to 7.1-fold) increased risk of venous thrombosis compared with nonusers of hormonal contraceptives. The use of a levonorgestrel intrauterine device was not associated with an increased risk (odds ratio, 0.3; 95% CI, 0.1 to 1.1). Unfortunately, the few women using a contraceptive patch or an implant prevented a reliable estimate of the risk of thrombosis.

Conclusion—

The risk of venous thrombosis was increased for injectable depot–medroxyprogesterone acetate contraceptive users, while we were able to reliably exclude an increased risk associated with levonorgestrel intrauterine device use. Therefore, the latter seems to be the safest option regarding the risk of venous thrombosis.
Predictors of Incident Heart Failure in a Large Insured Population
Authors: Goyal Abhinav , Norton Catherine R. , Thomas Tracy N. , Davis Robert L. , Butler Javed , Ashok Varun , Zhao Liping , Vaccarino Viola , Wilson Peter W.F.
Published: August 2010

Background—

Studies on the incidence and predictors of heart failure (HF) are often restricted to elderly persons or identify only inpatient cases.

Methods and Results—

We determined the incidence and predictors of new HF diagnosed in either outpatient or inpatient settings, among 359 947 women and men (age ≥18 years) insured by Kaiser Permanente Georgia at any time during calendar years 2000 to 2005. Subjects were free of HF at baseline, and incident HF was identified with ICD-9 codes (1 inpatient or 2 outpatient HF visits). We developed multivariable Cox models to assess the association of antecedent factors (coronary heart disease, hypertension, diabetes mellitus, atrial fibrillation, and valvular heart disease) with incident HF. Separate models were created for each sex and for newly diagnosed HF in outpatient or inpatient settings. There were 4001 incident HF cases (50% women and 48% in subjects <65 years old), during 1 015 794 person-years of follow-up. The incidence rate of HF was greater in men than in women (4.24 versus 3.68 per 1000 person-years) but was stable across the study interval in both sexes. Two thirds of incident HF cases from this population occurred in outpatients. These 5 antecedent factors and age yielded excellent discrimination for incident HF in both outpatients and inpatients and in both sexes (C >0.85 in all models).

Conclusions—

Common modifiable risk factors accurately discriminate women and men at risk for HF diagnosed in either outpatient or inpatient settings. Approximately two thirds of new HF cases in our insured population were diagnosed in outpatients; more research is needed to characterize these subjects and their prognosis.
Disruption of Protein Arginine
N
-Methyltransferase 2 Regulates Leptin Signaling and Produces Leanness In Vivo Through Loss of STAT3 Methylation
Authors: Iwasaki Hiroaki , Kovacic Jason C. , Olive Michelle , Beers Jeanette K. , Yoshimoto Takanobu , Crook Martin F. , Tonelli Leonardo H. , Nabel Elizabeth G.
Published: August 2010

Rationale:

Arginine methylation by protein
N
-arginine methyltransferases (PRMTs) is an important posttranslational modification in the regulation of protein signaling. PRMT2 contains a highly conserved catalytic Ado-Met binding domain, but the enzymatic function of PRMT2 with respect to methylation is unknown. The JAK-STAT pathway is proposed to be regulated through direct arginine methylation of STAT transcription factors, and STAT3 signaling is known to be required for leptin regulation of energy balance.

Objective:

To identify the potential role of STAT3 arginine methylation by PRMT2 in the regulation of leptin signaling and energy homeostasis.

Methods and Results:

We identified that
PRMT2
−/−
mice are hypophagic, lean, and have significantly reduced serum leptin levels. This lean phenotype is accompanied by resistance to food-dependent obesity and an increased sensitivity to exogenous leptin administration. PRMT2 colocalizes with STAT3 in hypothalamic nuclei, where it binds and methylates STAT3 through its Ado-Met binding domain. In vitro studies further clarified that the Ado-Met binding domain of PRMT2 induces STAT3 methylation at the Arg31 residue. Absence of PRMT2 results in decreased methylation and prolonged tyrosine phosphorylation of hypothalamic STAT3, which was associated with increased expression of hypothalamic proopiomelanocortin following leptin stimulation.

Conclusions:

These data elucidate a molecular pathway that directly links arginine methylation of STAT3 by PRMT2 to the regulation of leptin signaling, suggesting a potential role for PRMT2 antagonism in the treatment of obesity and obesity-related syndromes.
Optimizing Stroke Clinical Trial Design
Authors: Taylor Alexis , Castle Amanda , Merino José G. , Hsia Amie , Kidwell Chelsea S. , Warach Steven
Published: August 2010

Background and Purpose—

Clinical trial planning and site selection require an accurate estimate of the number of eligible patients at each site. In this study, we developed a tool to calculate the proportion of patients who would meet a specific trial’s age, baseline severity, and time to treatment inclusion criteria.

Methods—

From a sample of 1322 consecutive patients with acute ischemic cerebrovascular syndromes, we developed regression curves relating the proportion of patients within each range of the 3 variables. We used half the patients to develop the model and the other half to validate it by comparing predicted vs actual proportions who met the criteria for 4 current stroke trials.

Results—

The predicted proportion of patients meeting inclusion criteria ranged from 6% to 28% among the different trials. The proportion of trial-eligible patients predicted from the first half of the data were within 0.4% to 1.4% of the actual proportion of eligible patients. This proportion increased logarithmically with National Institutes of Health Stroke Scale score and time from onset; lowering the baseline limits of the National Institutes of Health Stroke Scale score and extending the treatment window would have the greatest impact on the proportion of patients eligible for a stroke trial.

Conclusions—

This model helps estimate the proportion of stroke patients eligible for a study based on different upper and lower limits for age, stroke severity, and time to treatment, and it may be a useful tool in clinical trial planning.
Association Between Human Immunodeficiency Virus Infection and Stiffness of the Common Carotid Artery
Authors: Seaberg Eric C. , Benning Lorie , Sharrett A. Richey , Lazar Jason M. , Hodis Howard N. , Mack Wendy J. , Siedner Mark J. , Phair John P. , Kingsley Lawrence A. , Kaplan Robert C.
Published: August 2010

Background and Purpose—

Individuals with human immunodeficiency virus (HIV) who use highly active antiretroviral therapy (HAART) may have an increased risk for cardiovascular-related events, although the underlying mechanism remains unclear. We tested the hypothesis that carotid arterial stiffness was higher among persons using HAART compared to HAART-naïve and HIV-uninfected persons.

Methods—

Between 2004 and 2006, we performed high-resolution B-mode ultrasound on 2789 HIV-infected and HIV-uninfected participants of the Women’s Interagency HIV Study (1865 women) and the Multicenter AIDS Cohort Study (924 men) and determined carotid arterial distensibility, which is a direct measure of carotid arterial stiffness. We used generalized estimating equations to evaluate the association between distensibility and HIV infection, CD4
+
cell count, and exposure to HAART adjusted for demographic, behavioral, and clinical characteristics.

Results—

In multivariable analysis, distensibility was 4.3% lower (95% confidence interval, −7.4% to −1.1%) among HIV-infected vs uninfected participants. Among HIV-infected participants with <200 CD4
+
cells, distensibility was 10.5% lower (95% confidence interval, −14.5% to −6.2%) than that among HIV-uninfected participants, and this effect did not differ significantly by cohort or race. Concurrent HAART use was independently associated with lower distensibility among Multicenter AIDS Cohort Study participants but not among Women’s Interagency HIV Study participants.

Conclusions—

Our finding that advanced HIV-related immunosuppression was associated with increased carotid arterial stiffness independent from the effects of traditional atherosclerosis risk factors suggests that the etiologic mechanism underlying reports of an increased cardiovascular disease risk among HIV-infected individuals might involve HIV-related immunosuppression leading to vascular dysfunction and arterial stiffening.
Correlation of Echocardiographic Findings With Cerebral Infarction in Elderly Adults
Authors: McAreavey Dorothea , Vidal Jean-Sébastien , Aspelund Thor , Owens David S. , Hughes Timothy , Garcia Melissa , Sigurdsson Sigurdur , Bjornsdottir Halldora , Harris Tamara B. , Gudnason Vilmundur , Launer Lenore J. , Plehn Jonathan F.
Published: August 2010

Background and Purpose—

Chronic effects of hypertension may be observed in multiple end organs. Previous reports suggest that cardiovascular morphological features can mirror cerebral infarction. In this cross-sectional analysis of elderly subjects, we investigated the relationship of a comprehensive set of echocardiographic measures with cerebral infarction detected by MRI.

Methods—

We compared echocardiographically determined left ventricular (LV) mass, left atrial volume, aortic root diameter, mitral annular calcification, and measures of diastolic function with cerebral infarction determined by MRI using logistic regression in a random sample drawn from the Age Gene/Environment Susceptibility-Reykjavik Study cohort. The model was first adjusted for age and gender, and then for age, gender, and vascular risk factors.

Results—

Among 692 subjects aged 75 (standard deviation, 6) years, 28% had at least 1 cerebral infarct. When adjusted for age and gender, the presence of cerebral infarction was modestly related to LV mass (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.00–1.02) and left atrial volume (OR, 1.03; 95% CI, 1.01–1.05), as well as the lowest quartile of early-to-late pulsed Doppler velocity ratio (early-to-late pulsed Doppler velocity ratio <0.75; OR, 1.87; 95% CI, 1.22–2.87). The latter relation remained significant after adjustment for vascular risk factors and LV ejection fraction (OR, 1.82; 95% CI, 1.16–2.86).

Conclusion—

Of all echocardiographic parameters, LV filling abnormality as indicated by low early-to-late pulsed Doppler velocity ratio displayed the strongest association with cerebral infarction and this relationship was independent of vascular risk factors. This simple marker of cerebral infarction may be useful when evaluating older patients.
How Much Would Performing Diffusion-Weighted Imaging for All Transient Ischemic Attacks Increase MRI Utilization?
Authors: Adeoye Opeolu , Heitsch Laura , Moomaw Charles J. , Alwell Kathleen , Khoury Jane , Woo Daniel , Flaherty Matthew L. , Ferioli Simona , Khatri Pooja , Broderick Joseph P. , Kissela Brett M. , Kleindorfer Dawn
Published: August 2010

Objectives—

The American Heart Association recently redefined TIA to exclude patients with infarction on neuroimaging. Given its advantages, MRI/diffusion-weighted imaging (DWI) was recommended as the preferred imaging modality. We determined how frequently MRI/DWI was performed for TIA and ascertained the proportion of clinically defined TIA patients who had ischemic lesions on DWI in our community in 2005.

Methods—

All clinically defined TIA cases among residents of a 5-county region around Cincinnati who presented to emergency departments were identified during 2005. Demographics and medical history, whether MRI/DWI was performed, and DWI findings were recorded. Generalized estimating equations were used to compare groups to account for the design of the study and multiple events per patient.

Results—

Of 834 TIA events in 799 patients, 323 events (40%) had MRI/DWI performed. Patients who had MRI/DWI were younger (mean, 66 vs 70 years;
P
=0.03), had less severe prestroke disability (baseline modified Rankin Scale score, 0; 44% vs 34%;
P
=0.02), were less likely to have previous stroke or TIA (42% vs 56%;
P
=0.002), and were less likely to have atrial fibrillation (10% vs 16%;
P
=0.01). Of the 323 events with DWI, 51 (15%) had evidence of acute infarction. Patients with positive DWI were older (75 vs 64 years;
P
=0.0001) and more likely to have atrial fibrillation (21% vs 7%;
P
=0.002).

Conclusion—

Performing MRI/DWI on all clinically defined TIA patients in our community would reveal more cases of actual infarction but would more than double current use. Future studies should assess whether MRI/DWI is warranted for all TIA patients.
Stroke Monitoring on a National Level
Authors: Meretoja Atte , Roine Risto O. , Kaste Markku , Linna Miika , Juntunen Merja , Erilä Terttu , Hillbom Matti , Marttila Reijo , Rissanen Aimo , Sivenius Juhani , Häkkinen Unto
Published: August 2010

Background and Purpose—

Stroke databases are established to systematically evaluate both the treatment and outcome of stroke patients and the structure and processes of stroke services. Comprehensive data collection on this common disease is resource-intensive, and national stroke databases often include only patients from selected hospitals. Here we describe an alternative national stroke database.

Methods—

We established a nationwide stroke database with multiple administrative registry linkages at the individual-patient level. Information on comorbidities; treatments before, during, and after stroke; living status; recurrences; case fatality; and costs were collected for each hospital-treated stroke patient.

Results—

The current database includes 94 316 patients with incident stroke between January 1999 and December 2007, with follow-up until December 2008. Annually, 10 500 new patients are being added. One-year recurrence was 13% and case fatality was 27% during the study period. In 2007, 86% of patients survived 1 month and 77% were living at home at 3 months, but the proportion treated in stroke centers (62%) or with nationally recommended secondary preventive medication after ischemic stroke (49%) was still suboptimal.

Conclusions—

In comparison with other national stroke databases, our method enables higher coverage and more thorough follow-up of patients. Information on long-term recurrences, case fatality, or costs is not often included in national stroke databases. Our database has low maintenance costs, but it lacks detailed data on in-hospital processes. Use of national administrative data, where such linkage is possible, saves resources, achieves high rates of long-term follow-up, and allows for comprehensive monitoring of the burden of the disease.
Accurate Quantification of Seasonal Rainfall and Associated Climate–Wildfire Relationships
Authors: Slocum Matthew G. , Platt William J. , Beckage Brian , Orzell Steve L. , Taylor Wayne
Published: August 2010

Wildfires are often governed by rapid changes in seasonal rainfall. Therefore, measuring seasonal rainfall on a temporally finescale should facilitate the prediction of wildfire regimes. To explore this hypothesis, daily rainfall data over a 58-yr period (1950–2007) in south-central Florida were transformed into cumulative rainfall anomalies (CRAs). This transformation allowed precise estimation of onset dates and durations of the dry and wet seasons, as well as a number of other variables characterizing seasonal rainfall. These variables were compared with parameters that describe ENSO and a wildfire regime in the region (at the Avon Park Air Force Range). Onset dates and durations were found to be highly variable among years, with standard deviations ranging from 27 to 41 days. Rainfall during the two seasons was distinctive, with the dry season having half as much as the wet season despite being nearly 2 times as long. The precise quantification of seasonal rainfall led to strong statistical models describing linkages between climate and wildfires: a multiple-regression technique relating the area burned with the seasonal rainfall characteristics had an of 0.61, and a similar analysis examining the number of wildfires had an of 0.56. Moreover, the CRA approach was effective in outlining how seasonal rainfall was associated with ENSO, particularly during the strongest and most unusual events (e.g., El Niño of 1997/98). Overall, the results presented here show that using CRAs helped to define the linkages among seasonality, ENSO, and wildfires in south-central Florida, and they suggest that this approach can be used in other fire-prone ecosystems.
A Higher-Order Ray Approximation Applied to Orographic Gravity Waves: Gaussian Beam Approximation
Authors: Pulido Manuel , Rodas Claudio
Published: August 2010

Ray techniques are a promising tool for developing orographic gravity wave drag schemes. However, the modeling of the propagation of orographic waves using standard ray theory in realistic background wind conditions usually encounters several regions, called caustics, where the first-order ray approximation breaks down. In this work the authors develop a higher-order approximation than standard ray theory, named the Gaussian beam approximation, for orographic gravity waves in a background wind that depends on height. The analytical results show that this formulation is free of the singularities that arise in ray theory. Orographic gravity waves that propagate in a background wind that turns with height—the same conditions as in the work of Shutts—are examined under the Gaussian beam approximation. The evolution of the amplitude is well defined in this approximation even at caustics and at the forcing level. When comparing results from the Gaussian beam approximation with high-resolution numerical simulations that compute the exact solution, there is good agreement of the amplitude and phase fields. Realistic orography is represented by means of a superposition of multiple Gaussians in wavenumber space that fit the spectrum of the orography. The technique appears to give a good representation of the disturbances generated by flow over realistic orography.