bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid changes in shear stress induce dissociation of a Gαq/11–platelet endothelial cell adhesion molecule‐1 complex
Authors: Otte Laura A. , Bell Kelly S. , Loufrani Laurent , Yeh Jiunn‐Chern , Melchior Benoît , Dao Diep N. , Stevens Hazel Y. , White Charles R. , Frangos John A.
Published: March 2009

It has been recently shown that endothelial platelet endothelial cell adhesion molecule‐1 (PECAM‐1) expression is pro‐atherogenic. PECAM‐1 is involved in sensing rapid changes in fluid shear stress but the mechanisms for activating signalling complexes at the endothelial cell junction have yet to be elucidated. Additional studies suggest the activation of membrane‐bound G proteins Gαq/11 also mediate flow‐induced responses. Here, we investigated whether PECAM‐1 and Gαq/11 could act in unison to rapidly respond to fluid shear stress. With immunohistochemistry, we observed a co‐localization of Gαq/11 and PECAM‐1 at the cell–cell junction in the atheroprotected section of mouse aortae. In contrast, Gαq/11 was absent from junctions in atheroprone areas as well as in all arterial sections of PECAM‐1 knockout mice. In primary human endothelial cells, temporal gradients in shear stress led to a rapid dissociation of the Gαq/11–PECAM‐1 complex within 30 s and a partial relocalization of the Gαq/11 staining to perinuclear areas within 150 min, whereas transitioning fluid flow devoid of temporal gradients did not disrupt the complex. Inhibition of G protein activation eliminated temporal gradient flow‐induced Gαq/11–PECAM‐1 dissociation. These results allow us to conclude that Gαq/11–PECAM‐1 forms a mechanosensitive complex and its localization suggests the Gαq/11–PECAM‐1 complex is a critical mediator of vascular diseases.
Numerical
and Analytical Modeling of Unbonded Flexible
Risers
Authors: Bahtui A. , Bahai H. , Alfano G.
Published: March 2009

This paper presents an analytical formulation and a finite element analysis of the behavior of multilayer unbonded flexible risers. The finite element model accurately incorporates all the fine details of the riser that were previously considered to be important but too difficult to simulate due to the significant associated computational cost. All layers of the riser are separately modeled, and contact interaction between layers has been accounted for. The model includes geometric nonlinearity as well as frictional effects. The analysis considers the main modes of flexible riser loading, which include internal and external pressures, axial tension, torsion, and bending. Computations were performed by employing a fully explicit time integration scheme on a parallel 16-processor cluster of computers. Consistency of simulation results was demonstrated by comparison with those of the analytical model of an identical structure. The close agreement gives confidence in both approaches.
Analysis of Submarine Pipeline Scour Using Large-Eddy Simulation of Dense Particle-Liquid Flows
Authors: Zamankhan Piroz
Published: March 2009

Using large-eddy simulation technique for dense particle-fluid flows, the current-induced scour is predicted for both the mono- and bidispersed systems below a horizontal submarine pipeline exposed to unidirectional flow. The simulations are four-way coupled, which implies that both solid-liquid and solid-solid interactions are taken into account. Particles are assumed to behave as viscoelastic solids during interactions with their neighboring particles, and their motion are predicted by a Lagrangian method. The interparticle normal and tangential contact forces between particles are calculated using a generalized Hertzian model. The other forces on a particle that are taken into account include gravitational pressure gradient force accounting for the acceleration of the displaced liquid, the drag force resulting from velocity difference with the surrounding liquid, and the Magnus and Saffman lift forces. The predicted scour profiles for monodispersed system are found to compare favorably with the laboratory observations. For the bidispersed system, a seepage flow underneath the pipe (which is a major factor to cause the onset of scour below the pipeline) is found to be weakened using an appropriate size for the sand bed. This fiffnding highlights the importance of the bed particle size distribution on the onset of scour below the pipelines.
Effects of MRI acquisition parameter variations and protocol heterogeneity on the results of texture analysis and pattern discrimination: An application‐oriented study
Authors: Mayerhoefer Marius E. , Szomolanyi Pavol , Jirak Daniel , Materka Andrzej , Trattnig Siegfried
Published: March 2009

MRI texture features are generally considered to be sensitive to variations in signal‐to‐noise ratio and spatial resolution, which represents an obstacle for the widespread clinical application of texture‐based pattern discrimination with MRI. This study investigates the sensitivity of texture features of different categories (co‐occurrence matrix, run‐length matrix, absolute gradient, autoregressive model, and wavelet transform) to variations in the number of acquisitions (NAs), repetition time (TR), echo time (TE), and sampling bandwidth (SBW) at different spatial resolutions. Special emphasis was placed on the influence of MRI protocol heterogeneity and implications for the results of pattern discrimination. Experiments were performed using two polystyrene spheres and agar gel phantoms with different nodular patterns. T2‐weighted multislice multiecho images were obtained using a 3.0 T scanner equipped with a microimaging gradient insert coil. Linear discriminant analysis and k nearest neighbor classification were used for texture‐based pattern discrimination. Results show that texture features of all categories are increasingly sensitive to acquisition parameter variations with increasing spatial resolution. Nevertheless, as long as the spatial resolution is sufficiently high, variations in NA, TR, TE, and SBW have little effect on the results of pattern discrimination. Texture features derived from the co‐occurrence matrix are superior to features of other categories because they enable discrimination of different patterns close to the resolution limits for the smallest structures of physical texture even for datasets that are heterogeneous with regard to different acquisition parameters, including spatial resolution.
Curved crystal x‐ray optics for monochromatic imaging with a clinical source
Authors: Bingölbali Ayhan , MacDonald C. A.
Published: March 2009

Monochromatic x‐ray imaging has been shown to increase contrast and reduce dose relative to conventional broadband imaging. However, clinical sources with very narrow energy bandwidth tend to have limited intensity and field of view. In this study, focused fan beam monochromatic radiation was obtained using doubly curved monochromator crystals. While these optics have been in use for microanalysis at synchrotron facilities for some time, this work is the first investigation of the potential application of curved crystal optics to clinical sources for medical imaging. The optics could be used with a variety of clinical sources for monochromatic slot scan imaging. The intensity was assessed and the resolution of the focused beam was measured using a knife‐edge technique. A simulation model was developed and comparisons to the measured resolution were performed to verify the accuracy of the simulation to predict resolution for different conventional sources. A simple geometrical calculation was also developed. The measured, simulated, and calculated resolutions agreed well. Adequate resolution and intensity for mammography were predicted for appropriate source/optic combinations.
Thermal modeling for pulsed radiofrequency ablation: Analytical study based on hyperbolic heat conduction
Authors: López Molina Juan A. , Rivera María J. , Trujillo Macarena , Berjano Enrique J.
Published: March 2009

The objectives of this study were to model the temperature progress of a pulsed radiofrequency (RF) power during RF heating of biological tissue, and to employ the hyperbolic heat transfer equation (HHTE), which takes the thermal wave behavior into account, and compare the results to those obtained using the heat transfer equation based on Fourier theory (FHTE). A theoretical model was built based on an active spherical electrode completely embedded in the biological tissue, after which HHTE and FHTE were analytically solved. We found three typical waveforms for the temperature progress depending on the relations between the dimensionless duration of the RF pulseand the expression, withas the dimensionless thermal relaxation time of the tissue andas the dimensionless position. In the case of a unique RF pulse, the temperature at any location was the result of the overlapping of two different heat sources delayed for a duration(each heat source being produced by a RF pulse of limitless duration). The most remarkable feature in the HHTE analytical solution was the presence of temperature peaks traveling through the medium at a finite speed. These peaks not only occurred during the RF power switch‐on period but also during switch off. Finally, a physical explanation for these temperature peaks is proposed based on the interaction of forward and reverse thermal waves. All‐purpose analytical solutions for FHTE and HHTE were obtained during pulsed RF heating of biological tissues, which could be used for any value of pulsing frequency and duty cycle.
Optimization of the acquisition geometry in digital tomosynthesis of the breast
Authors: Sechopoulos Ioannis , Ghetti Caterina
Published: March 2009

Digital tomosynthesis of the breast continues to be intensively studied as an adjunct or replacement of conventional mammography. Although many of the acquisition parameters found in tomosynthesis imaging are also found in conventional mammography and therefore most of the traditional values from mammography have been used in the former, two acquisition geometry parameters, the angular range covered during acquisition and the number of projections per projection set, are applicable only to tomosynthesis. Therefore, in the preclinical and clinical studies reported on tomosynthesis of the breast, a wide variety of values have been used for these two parameters. In this study, 63 different combinations of angular range and number of projections were evaluated using computer simulation methods to characterize how these two parameters affect reconstruction quality and to find which of these combinations maximize it. For this, a computer simulation of a digital tomosynthesis system that included empirically determined system response characteristics was developed and used to generate 9450 different breast tissue volume reconstructions. These reconstructions were analyzed objectively using metrics for in‐plane lesion visibility and vertical resolution in the form of the contrast‐to‐noise ratio and artifact spread function (ASF). It was found that although maximizing the angular range covered does always increase the vertical resolution in tomosynthesis, increasing the number of projections in the acquisition set beyond a relatively low threshold does not further improve the vertical resolution. This threshold value for the minimal number of projections needed to minimize the ASF was found to vary proportionally with angular range. For example, for a 60° angular range, the threshold number of projections was found to be 13. Given the clear inverse relationship between the number of projections and in‐plane reconstruction quality under a limited total glandular dose condition, the optimum acquisition geometry in tomosynthesis imaging of the breast is that which maximizes the angular range while maintaining the number of projections close to the threshold values found. Finally, of the 63 acquisition geometries studied, the one that resulted in the highest quality reconstruction, considering both in‐plane quality and vertical resolution, consisted of the acquisition of 13 projections over a 60° angular range.
Dosimetric evaluation of sucrose and granulated cane sugar in the therapeutic dose range
Authors: Davidson Melanie T. M. , Jordan Kevin J.
Published: March 2009

Granulated cane sugar has been used as a dosimetric material to report dose in high dose accidental irradiations. The purpose of this study was to assess whether clinical dosimetry is also plausible with such a commonly available material. The behavior of cane sugar was explored with respect to therapeutically relevant radiation quantities (dose, dose rate) and qualities (energy, radiation type) as well as under different temperature conditions. The stability of the signal postirradiation was also measured. Absorbed dose was measured by spectrophotometric readout of a ferrous ammonium sulfate xylenol orange (FX)‐sugar solution in 10 cm path length cells. A visible color change was produced as a function of dose when the irradiated sugar samples were dissolved in FX solution (10% dilution by mass). A comparison of the optical absorbance spectra and dose response of cane sugar with analytical grade sucrose was done to establish a benchmark standard from which subsequent dosimetry measurements can be validated. The response of the sugar dosimeter read at 590 nm was found to be linear over the dose range of 100–2000 cGy, independent of energy (6–18 MV) and of the average dose rate (100–500 cGy/min). The readout of sugar samples irradiated with mixed photon and electron fields was also shown to be independent of radiation type (photons and electrons). Sugar temperature during irradiation did not affect dose estimates, making it a promising dosimeter for in vivo dosimetry, particularly in cases where the dosimeter must remain in contact with the patient for an extended period of time. Sugar can be used as an integrating dosimeter, since it exhibits no fractionation effects. Granulated cane sugar is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.
Integron Mobilization Unit as a Source of Mobility of Antibiotic Resistance Genes
Authors: Poirel Laurent , Carrër Amélie , Pitout Johann D. , Nordmann Patrice
Published: March 2009

Antibiotic resistance genes are spread mostly through plasmids, integrons (as a form of gene cassettes), and transposons in gram-negative bacteria. We describe here a novel genetic structure, named the integron mobilization unit (IMU), that has characteristics similar to those of miniature inverted transposable elements (MITEs). Two IMUs (288 bp each) were identified from a carbapenem-resistant
Enterobacter cloacae
isolate that formed a composite structure encompassing a defective class 1 integron containing the carbapenem resistance gene
bla
GES-5
. This ß-lactamase gene was located on a 7-kb IncQ-type plasmid named pCHE-A, which was sequenced completely. The plasmid pCHE-A was not self conjugative but was mobilizable, and it was successfully transferred from
E. cloacae
to
Pseudomonas aeruginosa
. The in silico analysis of the extremities of the IMU elements identified similarities with those of insertion sequence IS
Sod9
from
Shewanella oneidensis
MR-1. The mobilization of the IMU composite structure was accomplished by using the transposase activity of IS
Sod9
that was provided in
trans
. This is the first identification of MITE-type structures as a source of gene mobilization, implicating here a clinically relevant antibiotic resistance gene.
Antibiotic Susceptibility of
Waddlia chondrophila
in
Acanthamoeba castellanii
Amoebae
Authors: Goy Geneviève , Greub Gilbert
Published: March 2009

Waddlia chondrophila
is an emerging cause of miscarriage in bovines and humans. Given the strict intracellular growth of this
Chlamydia
-like organism, its antibiotic susceptibility was tested by amoebal coculture, cell culture, and real-time PCR.
W. chondrophila
was susceptible to doxycycline and azithromycin but resistant to β-lactams and fluoroquinolones.
Analysis of Cell Membrane Characteristics of In Vitro-Selected Daptomycin-Resistant Strains of Methicillin-Resistant
Staphylococcus aureus
Authors: Mishra Nagendra N. , Yang Soo-Jin , Sawa Ayumi , Rubio Aileen , Nast Cynthia C. , Yeaman Michael R. , Bayer Arnold S.
Published: March 2009

Our previous studies of clinical daptomycin-resistant (Dap
r
)
Staphylococcus aureus
strains suggested that resistance is linked to the perturbations of several key cell membrane (CM) characteristics, including the CM order (fluidity), phospholipid content and asymmetry, and relative surface charge. In the present study, we examined the CM profiles of a well-known methicillin-resistant
Staphylococcus aureus
(MRSA) strain (MW2) after in vitro selection for DAP resistance by a 20-day serial passage in sublethal concentrations of DAP. Compared to levels for the parental strain, Dap
r
strains exhibited (i) decreased CM fluidity, (ii) the increased synthesis of total lysyl-phosphatidylglycerol (LPG), (iii) the increased flipping of LPG to the CM outer bilayer, and (iv) the increased expression of
mprF
, the gene responsible for the latter two phenotypes. In addition, we found that the expression of the
dlt
operon, which also increases positive surface charge, was enhanced in the Dap
r
mutants. These phenotypic and genotypic changes correlated with reduced DAP surface binding, mirroring observations made in clinical Dap
r
isolates. In this strain, serial exposure to DAP induced an increase in vancomycin MICs into the vancomycin-intermediate
S. aureus
(VISA) range (4 μg/ml) in parallel with increasing DAP MICs. Also, this Dap
r
strain exhibited significantly thicker cell walls than the parental strain, potentially correlating with the coevolution of the VISA phenotype and implicating cell wall structure and/or function in the Dap
r
phenotype. Importantly, despite the overexpression of
mprF
and
dlt
, the relative net positive surface charge was decreased in the Dap
r
mutants, suggesting that other factors contribute to the surface charge alterations and that a simple charge repulsion mechanism could not entirely explain the Dap
r
phenotype in these strains.
Role of p38 and Early Growth Response Factor 1 in the Macrophage Response to Group B Streptococcus
Authors: Kenzel Sybille , Santos-Sierra Sandra , Deshmukh Sachin D. , Moeller Inga , Ergin Bilge , Fitzgerald Katherine A. , Lien Egil , Akira Shizuo , Golenbock Douglas T. , Henneke Philipp
Published: March 2009

Group B streptococcus (GBS), the most frequent single isolate in neonatal sepsis and meningitis, potently activates inflammatory macrophage genes via myeloid differentiation antigen 88 (MyD88). However, events parallel to and downstream of MyD88 that instruct the macrophage response are incompletely understood. In this study, we found that only MyD88, not the Toll-like receptor (TLR) adapter proteins MAL/TIRAP, TRIF, and TRAM, essentially mediates the cytokine (tumor necrosis factor [TNF] and interleukin-6) and chemokine (RANTES) responses to whole GBS organisms, although MAL, TRIF, and TRAM have been shown to mediate the responses to substructures in other gram-positive and gram-negative bacteria. GBS-induced, MyD88-dependent phosphorylation of the mitogen-activated protein kinase p38 activated the transcription factor AP-1 and early growth response factor 1 (Egr-1) but not NF-κB. Furthermore, phosphorylation of Ets-like molecule 1 (Elk-1) was mediated by p38. However, in contrast to Egr-1 and AP-1, Elk-1 was dispensable for transcriptional activation of TNF by GBS organisms. Studies of macrophages from Elk-1-deficient mice revealed that Elk-1 was furthermore nonessential for the TNF responses to purified TLR2 and TLR4 agonists, which was in notable contrast to what was revealed in studies employing in vitro expression systems. In conclusion, MyD88, p38, and Egr-1, but not Elk-1, essentially mediate the inflammatory cytokine response to GBS organisms.
Differentiation of three closely related Japanese oak species and detection of interspecific hybrids using AFLP markers
Authors: Matsumoto Asako , Kawahara Takayuki , Kanazashi Ayako , Yoshimaru Hiroshi , Takahashi Makoto , Tsumura Yoshihiko
Published: March 2009

Three white-oak species ( Quercus crispula Blume, Quercus dentata Thunb., and Quercus serrata Thunb.) are native, widely distributed, and prominent species in the temperate deciduous forests of Japan. They are closely related to each other and overlapping morphological variation in some traits is observed, although they differ from each other in appearance. To distinguish these species genetically, we carried out clustering analysis based on Bayesian approach by AFLP markers using morphologically typical trees. Although no completely species-specific markers were obtained, these species could be distinguished and their genetic relationships were evaluated based on differences in frequencies of 66 polymorphic markers, including four that were almost completely species-specific. We also attempted to characterize putative interspecific hybrids between Q. crispula and Q. dentata sampled in a mixed stand. Two programs, HINDEX and STRUCTURE, were successfully used to detect several hybrid individuals without any prior information about their morphological traits. However, STRUCTURE and HINDEX gave conflicting indications regarding the admixture levels in some individuals.
Yielding and Flow of Sand in Triaxial Compression: Part I
Authors: Poorooshasb H B , Holubec I , Sherbourne A N
Published: March 2009

A theoretical and experimental study of the nature of deformation of a sand sample when tested in the triaxial apparatus is presented. The medium is shown to be elastic-strain hardening plastic but does not conform to certain rules usually adopted in the classical theory of plasticity. Experimental verification of an earlier suggestion by Poorooshasb (1961) leads to a proof of the existence of a potential function, known as the plastic potential, of the form Ψ(σ, e) the parameters σ representing the stress and e the voids ratio. The plastic potential curves defined by Ψ = constant, e = constant, trace a family of geometrically similar curves when plotted in a stress space. The yield loci, on the other hand, are found to be independent of voids ratio and are only functions of the ratio of the second invariant of the stress deviation tensor to the first invariant of the stress tensor. It is noted, therefore, that the plastic potential and yield surface are not coincidental. This defies the normality condition and in this respect the medium's behaviour appears to deviate from that of a classical plastic body. Although the scope of the study is limited, being applicable only to stress conditions provided in a triaxial compression test, extensions are made to incorporate stress and strain in their more general form. This is done to stimulate further research on the subject, although a fair amount of evidence is available to support, qualitatively at least, the validity of the propositions made. The paper is concluded by presenting the flow rule for the medium and discussing the application of the theory presented to the solution of equilibrium and eigenvalue problems involving stress and deformation.
Influence of leaf wetness, temperature, and rain on poplar leaf rust epidemics
Authors: Hamelin Richard C. , Shain Louis , Thielges Bart A.
Published: March 2009

Severe epidemics of poplar leaf rust, caused by Melampsoramedusae Thüm. f.sp. deltoidae, developed on eastern cottonwood, Populusdeltoides Bartr., in 1988 and 1989 in a mixed clonal plantation and in a natural stand in western Kentucky despite precipitation deficits and high maximum temperatures during the exponential phase of the epidemic. Minimum temperatures during that period, however, were within the range reported to be optimal for uredospore germination (15–21 °C). Average duration of leaf wetness for the entire epidemic was 10.6 h in 1988, and 11.2 and 11.7 h in 1989 in the natural stand and the plantation, respectively. Maximum infection of artificially inoculated detached leaves of eastern cottonwood occurred after 8 h of continuous leaf wetness. These results suggest that rain deficit and high maximum temperatures are not limiting factors for poplar leaf rust epidemics when night conditions frequently offer optimal temperature and leaf wetness for infection.
Croissance en hauteur de l'épinette noire: région de Lebel-sur-Quévillon et de Dolbeau au Québec
Authors: Zarnovican Richard
Published: March 2009

Height growth of black spruce was studied from stem analysis in 72 circular plots of 0.1 ha located in the Lebel-sur-Quévillon and Dolbeau regions, province of Quebec. Tree age analysis showed that only 52 of these plots were evenly aged; therefore, only these were retained in the present study. Mean age determined at diameter at breast height was as variable as mean total age. The comparison of Plonski's and Vézina and Linteau's parameterized site-index curves suggested that Plonski's model is more suitable for asymptotic growth of black spruce. The comparison of parameterized average height curves from 52 plots with Plonski's curves indicated that black spruce height growth in these regions is not uniform; four different growing forms corresponding to temporal structures can be distinguished. These growing forms can have asymptotic or linear curves; these can coincide with or cut across the Plonski's site-class curves, according to the increase or decrease in height growth with age. Finally, the growing forms are also found by parameters of Korf's growth function, by height increments, and by ages at which height increment is highest.
Spatial extent of impact of red alder on soil chemistry of adjacent conifer stands
Authors: Rhoades Charles C. , Binkley Dan
Published: March 2009

We examined patterns in soil N availability and pH along transects extending from mixed stands of conifers (mostly Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco)) and red alder (Alnusrubra Bong.) to pure conifer stands at two locations. At the relatively infertile Wind River site, increased N availability was apparent for about 8–12 m downslope of the alder–conifer stand, but no effect was apparent upslope. At the fertile Cascade Head site, no trend was apparent in N availability across the stand boundaries, but soil pH in the conifer stand was depressed for about 5 m from the alder–conifer stand. Overall, the effects of alder on soil chemistry appeared limited to a distance of less than half the height of the trees.
HYBRID CHAPLYGIN GAS
Authors: ZHANG HONGSHENG , ZHU ZONG-HONG , YANG LIHUA
Published: March 2009

Hybrid Chaplygin gas model is put forward, in which the gases play the role of dark energy. For this model the coincidence problem is greatly alleviated. The effective equation of state of the dark energy may cross the phantom divide w = -1. Furthermore, the crossing behavior is decoupled from any gravity theories. In the present model, w < -1 is only a transient behavior. There is a de Sitter attractor in the future infinity. Hence, the big rip singularity, which often afflicts the models with matter whose effective equation of state less than -1, naturally disappears. There exist stable scaling solutions, both at the early universe and the late universe. We discuss the perturbation growth of this model. We find that the index is consistent with observations.
DEEP-ELASTIC pp SCATTERING AT LHC FROM LOW-x GLUONS
Authors: ISLAM M. M. , KAŠPAR J. , LUDDY R. J.
Published: March 2009

Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum transfer range 4 GeV 2 ≲ |t| ≲ 10 GeV 2 is planned to be measured by the TOTEM group. We study this process in a model where the deep-elastic scattering is due to a single hard collision of a valence quark from one proton with a valence quark from the other proton. The hard collision originates from the low-x gluon cloud around one valence quark interacting with that of the other. The low-x gluon cloud can be identified as color glass condensate and has size ≃0.3 F. Our prediction is that pp dσ/dt in the large |t| region decreases smoothly as momentum transfer increases. This is in contrast to the prediction of pp dσ/dt with visible oscillations and smaller cross sections by a large number of other models.
PRETREATMENT METHOD RESEARCH OF NEAR-INFRARED SPECTRA IN BLOOD COMPONENT NON-INVASIVE MEASUREMENT
Authors: LI LI NA , ZHANG GUANG JUN , LI QING BO
Published: March 2009

Blood component non-invasive measurement based on near-infrared (NIR) spectroscopy has become a favorite topic in the field of biomedicine. However, the various noises from instrument measurement and the varying background from absorption of other components (except target analyte) in blood are the main causes, which influenced the prediction accuracy of multivariable calibration. Thinking of backgrounds and noises are always found in high-scale approximation and low-scale detail coefficients. It is possible to identify them by wavelet transform (WT), which has multi-resolution trait and can break spectral signals into different frequency components retaining the same resolution as the original signal. Meanwhile, associating with a criterion of uninformative variable elimination (UVE), it is better to eliminate backgrounds and noises simultaneously and visually. Basic principle and application technology of this pretreatment method, wavelet transform with UVE criterion, were presented in this paper. Three experimental near-infrared spectra data sets, including aqueous solution with four components data sets, plasma data sets, body oral glucose tolerance test (OGTT) data sets, which, including glucose (the target analyte in this study), have all been used in this paper as examples to explain this pretreatment method. The effect of selected wavelength bands in the pretreatment process were discussed, and then the adaptability of different pretreatment method for the uncertainty complex NIR spectra model in blood component non-invasive measurements were also analyzed. This research indicates that the pretreatment methods of wavelet transform with UVE criterion can be used to eliminate varying backgrounds and noises for experimental NIR spectra data directly. Under the spectra area of 1100 to 1700 nm, utilizing this pretreatment method is helpful for us to get a more simple and higher precision multivariable calibration for blood glucose non-invasive measurement. Furthermore, by comparing with some other pretreatment methods, the results imply that the method applied in this study has more adaptability for the complex NIR spectra model. This study gives us another path for improving the blood component non-invasive measurement technique based on NIR spectroscopy.
SYMBOLIC APPROACHES FOR FINDING CONTROL STRATEGIES IN BOOLEAN NETWORKS
Authors: LANGMEAD CHRISTOPHER JAMES , JHA SUMIT KUMAR
Published: March 2009

We present an exact algorithm, based on techniques from the field of Model Checking, for finding control policies for Boolean Networks (BN) with control nodes. Given a BN, a set of starting states, I, a set of goal states, F, and a target time, t, our algorithm automatically finds a sequence of control signals that deterministically drives the BN from I to F at, or before time t, or else guarantees that no such policy exists. Despite recent hardness-results for finding control policies for BNs, we show that, in practice, our algorithm runs in seconds to minutes on over 13,400 BNs of varying sizes and topologies, including a BN model of embryogenesis in Drosophila melanogaster with 15,360 Boolean variables. We then extend our method to automatically identify a set of Boolean transfer functions that reproduce the qualitative behavior of gene regulatory networks. Specifically, we automatically learn a BN model of D. melanogaster embryogenesis in 5.3 seconds, from a space containing 6.9 × 1010possible models.
SERVICE ORIENTED TECHNOLOGY MANAGEMENT TO IMPROVE ORGANIZATIONAL AGILITY
Authors: DEMIRKAN HALUK , GOUL MICHAEL
Published: March 2009

The service orientation — coupled with dynamic choreography of business processes, service oriented architectures and service oriented infrastructures — is a developing structure that carries with it the potential to improve agility in today's complex business environments. But because of the newness of the concept and the limited number of large-scale organizations ready or willing to be "early adopters," it is difficult to predict the organizational and technical impacts, understand the critical issues, or perform rigorous research on services computing. So, how should a company begin assessing the real impacts of these service orientation paradigm shifts? In this article, we established an integrated assessment process for creating an organizational roadmap to realize visions of how to deliver reliable, scalable enterprise processes built upon services-computing.
CONVERGENCE AND INNOVATION IN TELECOMMUNICATION SERVICES: AN ASSESSMENT FROM THE PERSPECTIVE OF THE COMPLEMENTARY ASSETS AND DYNAMIC CAPABILITIES THEORIES
Authors: CUNHA AMERICO BRIGIDO
Published: March 2009

Most of the telecommunications service providers, TSPs, are running their businesses based on few profitable services from the eighties, despite the fact that new network technologies have already been disposed of the organization infrastructures to provide new convergent services. The introduction of new telecommunications services seems to lag behind the rate of technological innovations in network equipment and the devices of end users. Consequently, this paper investigates whether or not the internal resources configuration of the Brazilian TSPs is affecting their capacity for services innovation. Based on an evaluation of the critical assets to telecommunications services innovation, this paper concludes with a discussion about TSP organization boundaries and outsourcing strategies.
Multiple Defects in Intracellular Calcium Cycling in Whole Failing Rat Heart
Authors: Wasserstrom J. Andrew , Sharma Rohan , Kapur Sunil , Kelly James E. , Kadish Alan H. , Balke C. William , Aistrup Gary L.
Published: March 2009

Background—

A number of defects in excitation-contraction coupling have been identified in failing mammalian hearts. The goal of this study was to measure the defects in intracellular Ca
2+
cycling in left ventricular epicardial myocytes of the whole heart in an animal model of congestive heart failure (CHF).

Methods and Results—

Intracellular Ca
2+
transients were measured using confocal microscopy in whole rat hearts from age-matched Wistar-Kyoto control rats and spontaneously hypertensive rats at ≈23 months of age. Basal Ca
2+
transients in myocytes in spontaneously hypertensive rats were smaller in amplitude and longer in duration than Wistar-Kyoto control rats. There was also greater variability in transient characteristics associated with duration between myocytes of CHF than Wistar-Kyoto controls. Approximately 21% of CHF myocytes demonstrated spontaneous Ca
2+
waves compared with very little of this activity in Wistar-Kyoto control rats. A separate population of spontaneously hypertensive rat myocytes showed Ca
2+
waves that were triggered during pacing and were absent at rest (triggered waves). Rapid pacing protocols caused Ca
2+
alternans to develop at slower heart rates in CHF.

Conclusions—

Epicardial cells demonstrate both serious defects and greater cell-to-cell variability in Ca
2+
cycling in CHF. The defects in Ca
2+
cycling include both spontaneous and triggered waves of Ca
2+
release, which promote triggered activity. The slowing of Ca
2+
repriming in the sarcoplasmic reticulum is probably responsible for the increased vulnerability to Ca
2+
alternans in CHF. Our results suggest that defective Ca
2+
cycling could contribute both to reduced cardiac output in CHF and to the establishment of repolarization gradients, thus creating the substrate for reentrant arrhythmias.
Abciximab in Patients With Acute ST-Segment–Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention After Clopidogrel Loading
Authors: Mehilli Julinda , Kastrati Adnan , Schulz Stefanie , Früngel Stefan , Nekolla Stephan G. , Moshage Werner , Dotzer Franz , Huber Kurt , Pache Jürgen , Dirschinger Josef , Seyfarth Melchior , Martinoff Stefan , Schwaiger Markus , Schömig Albert
Published: March 2009

Background—

The glycoprotein IIb/IIIa receptor inhibitor abciximab has improved the efficacy of primary percutaneous coronary interventions in patients with acute myocardial infarction. However, it is not known whether abciximab remains beneficial after adequate clopidogrel loading in patients with acute ST-segment–elevation myocardial infarction.

Methods and Results—

A total of 800 patients with acute ST-segment–elevation myocardial infarction within 24 hours from symptom onset, all treated with 600 mg clopidogrel, were randomly assigned in a double-blind fashion to receive either abciximab (n=401) or placebo (n=399) in the intensive care unit before being sent to the catheterization laboratory. The primary end point, infarct size measured by single-photon emission computed tomography with technetium-99m sestamibi before hospital discharge, was 15.7±17.2% (mean±SD) of the left ventricle in the abciximab group and 16.6±18.6% of the left ventricle in the placebo group (
P
=0.47). At 30 days, the composite of death, recurrent myocardial infarction, stroke, or urgent revascularization of the infarct-related artery was observed in 20 patients in the abciximab group (5.0%) and 15 patients in the placebo group (3.8%) (relative risk, 1.3; 95% CI, 0.7 to 2.6;
P
=0.40). Major bleeding complications were observed in 7 patients in each group (1.8%).

Conclusion—

Upstream administration of abciximab is not associated with a reduction in infarct size in patients presenting with acute myocardial infarction within 24 hours of symptom onset and receiving 600 mg clopidogrel.
Four Blood Pressure Indexes and the Risk of Stroke and Myocardial Infarction in Japanese Men and Women
Authors: Miura Katsuyuki , Nakagawa Hideaki , Ohashi Yasuo , Harada Akiko , Taguri Masataka , Kushiro Toshio , Takahashi Atsuhiko , Nishinaga Masanori , Soejima Hirofumi , Ueshima Hirotsugu
Published: March 2009

Background—

Information has been sparse on the comparison of 4 blood pressure (BP) indexes (systolic BP [SBP], diastolic BP, pulse pressure, and mean BP [MBP]) in relation to long-term incidence of stroke and myocardial infarction, particularly in middle-aged and older Asians.

Methods and Results—

The Japan Arteriosclerosis Longitudinal Study Group conducted a meta-analysis of 16 cohort studies in Japan. A total of 48 224 men and women 40 to 89 years of age participated at baseline, and 1231 stroke events and 220 myocardial infarction events occurred during an average 8.4-year follow-up. Multivariate-adjusted hazard ratios with a 1-SD higher value for each BP index were determined by Poisson regression. Analyses were also done in 4 age-sex groups. All 4 BP indexes were significantly related to all stroke risk. Stroke risk was most strongly related to MBP and SBP in both sexes and most weakly related to pulse pressure. Both stroke subtypes, ischemic and hemorrhagic, were most strongly related to MBP and SBP in both sexes. In addition, in men and women 70 to 89 years of age, MBP or SBP showed the strongest relation to all stroke risk. Myocardial infarction risk was most strongly related to SBP or MBP in both sexes. For any end points in any age-sex groups, pulse pressure was not the strongest predictor.

Conclusions—

The long-term incident risk of stroke and myocardial infarction associated with high BP in East Asian populations should be assessed mainly on the basis of SBP. MBP also may be an important predictor, but pulse pressure is a less important predictor for cardiovascular disease risk.
Effects of Recent Environmental Changes on Global Seismicity and Volcanism
Authors: Podolskiy Evgeny A.
Published: March 2009

A covariation of recent global environmental changes and seismicity on Earth is demonstrated. Presently, rising concern about anthropogenic activities and their consequences on the cryosphere and environment have always overlooked changes related to future tectonic activity. Possible factors affecting an increase in the number of earthquakes and volcanic eruptions are reviewed and discussed.
Exploring the Transient Behavior of Z–R Relationships: Implications for Radar Rainfall Estimation
Authors: Prat Olivier P. , Barros Ana P.
Published: March 2009

The objective of this study is to characterize the signature of dynamical microphysical processes on reflectivity–rainfall (Z–R) relationships used for radar rainfall estimation. For this purpose, a bin model with explicit microphysics was used to perform a sensitivity analysis of the shape parameters of the drop size distribution (DSD) as a function of time and rainfall regime. Simulations show that coalescence is the dominant microphysical process for low to moderate rain intensity regimes (R < 20 mm h−1) and that the rain rate in this regime is strongly dependent on the spectral properties of the DSD (i.e., the shape). The time to equilibrium for light rainfall is at least twice as long as in the case of heavy rainfall (1 h for stratiform vis-à-vis 30 min for thunderstorms). For high-intensity rainfall (R > 20 mm h−1), collision–breakup dynamics dominate the evolution of the raindrop spectra. The time-dependent Z–R relationships produced by the model converge to a universal Z–R relationship for heavy intensity rainfall (A = 1257; b ∼ 1) centered on the region of Z–R space defined by the ensemble of over 100 empirical Z–R relationships. Given the intrinsically transient nature of the DSD for light rainfall, it is proposed that the vertical raindrop spectra and corresponding rain rates should be modeled explicitly by a microphysical model. A demonstration using a multicolumn simulation of a Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) overpass over Darwin for a stratiform event during the Tropical Warm Pool–International Cloud Experiment (TWP-ICE) is presented.
Evaluation of Planetary Boundary Layer Parameterizations in Tropical Cyclones by Comparison of In Situ Observations and High-Resolution Simulations of Hurricane Isabel (2003). Part I: Initialization, Maximum Winds, and the Outer-Core Boundary Layer
Authors: Nolan David S. , Zhang Jun A. , Stern Daniel P.
Published: March 2009

In this study, the first of two parts, the planetary boundary layer (PBL) depicted in high-resolution Weather Research and Forecast Model (WRF) simulations of Hurricane Isabel (2003) is studied and evaluated by direct comparisons with in situ data obtained during the Coupled Boundary Layer and Air–Sea Transfer Experiment (CBLAST). In particular, two boundary layer schemes are evaluated: the Yonsei University (YSU) parameterization and the Mellor–Yamada–Janjić (MYJ) parameterization. Investigation of these schemes is useful since they are available for use with WRF, are both widely used, and are based on entirely different methods for simulating the PBL.

In this first part, the model domains and initialization are described. For additional realism of the low-level thermodynamic environment, a simple mixed layer ocean model is used to simulate ocean cooling. The YSU and MYJ schemes are discussed, along with some modifications. Standard measures of the accuracy of the hurricane simulations, such as track, maximum surface wind speed, and minimum surface pressure are described for a variety of parameter choices and for the two parameterizations. The effects on track and intensity of increased horizontal and vertical resolutions are also shown. A modification of the original YSU and MYJ schemes to have ocean roughness lengths more in agreement with recent studies considerably improves the results of both schemes. Instantaneous wind maxima on the innermost grid with 1.33-km resolution are shown to be an accurate representation of the simulated 1-min sustained winds.

The simulated boundary layers are evaluated by direct comparison of the PBL as simulated and as observed by in situ data from the CBLAST experiment in the “outer core” region of the storm. The two PBL schemes and their modified counterparts reproduce the observed PBL remarkably well. Comparisons are also made to the observed vertical fluxes of momentum, heat, and moisture.

In Part II, the detailed comparisons of the intensities and structures of the simulated and observed inner-core boundary layers are presented, and the reasons for the differences are discussed.
A More Sophisticated Merton
Authors: Kincaid Harold
Published: March 2009

An alternative account of Merton to that provided by Turner is sketched. It shows strong similarities to some quite plausible contemporary understandings of science in general. Given this reading, it would seem that Merton did not drastically change his position nor does it suffer from the ambiguities that Turner describes.
Youth Assets and Delayed Coitarche Across Developmental Age Groups
Authors: Aspy Cheryl B. , Vesely Sara K. , Tolma Eleni L. , Oman Roy F. , Rodine Sharon , Marshall LaDonna , Fluhr Janene
Published: March 2009

Cross-sectional studies suggest that assets are associated with youth abstinence, but whether these relationships are constant across developmental age groups has not been shown. Data for this study were obtained from two independent datasets collected across a 2-year period using in-person, in-home interviews of youth (52% female; 44% Caucasian, 23% Hispanic, 23% African-American, 10% other) and their parents (N = 2163 youth/parent pairs). Eighty-eight percent of teens aged 12-14 and 58% of teens aged 15-17 reported no sexual intercourse. Individual logistic regression models for assets and abstinence found 5 youth assets with significant adjusted odds ratios for both age groups: Non-Parental Adult Role models; Family Communication; Use of Time (Religion); Responsible Choices; and Peer Role Models. Community Involvement was associated with abstinence for young teens only and Aspirations for the Future and Good Health Practices only for middle teens. These findings can inform policies and programs targeting youth sexual decision-making.