bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Fully Implicit, Parallel, EOS Compositional Simulator to Model Asphaltene Precipitation in Petroleum Reservoirs
Authors: Fazelipour Waleed , Pope Gary A. , Sepehrnoori Kamy
Published: September 2008

A serious and complex problem in hydrocarbon recovery is the asphaltene precipitation since it affects all aspects of petroleum production, processing, and consequently transportation. It is very desireable to predict and simulate the asphaltene precipitation during upstream recovery processes from oil and gas reservoirs. Many models have been developed to predict the precipitation behavior of asphaltenes.

We present implementation of an asphaltene precipitation model into a fully implicit, 3D, parallel, multiphase, multicomponent, EOS compositional simulator called GPAS developed at the Center for Petroleum and Geosystems Engineering to model the phase behavior and simulate the dynamic aspects of the asphaltene precipitation problem that occurs in oil and gas reservoirs.

After studying many models for asphaltene precipitation available in the petroleum engineering literature, testing and utilizing various simulators (e.g. ECLIPSE, CMG, VIP) to simulate the problem under primary depletion, CO2 and water flooding scenarios, a particular thermodynamic approach was chosen to be implemented in the GPAS simulator. This model treats the precipitating asphaltene as a single component residing in a pure solid phase, while hydrocarbon phases are modeled with an EOS.

The primary goal of GPAS, currently under development, is to support realistic, high-resolution reservoir studies using millions of gridcells on massively parallel computers. Key features for this simulator include the ability to handle multiple physical models, multiple fault blocks, and flexible gridding.

With the incorporation of asphaltene simulation into GPAS, many equations in the original code were modified, added, and implemented including the phase equilibrium, volume constraint, and mass conservation equations. Multiphase flash calculations were developed to predict the onset point and the amount of asphaltene precipitation throughout the life of a reservoir. Since this phenomenon severely damages the physical properties of formation, models were also implemented to estimate the effects on porosity, relative permeability, and wettability. The fully implicit formulations of GPAS added a great deal to the complexity of the formulations.

Simulation results indicate that asphaltene precipitation reduces oil production. A key conclusion of the achivements is the capability to predict the detrimental effects of asphaltenes in reservoirs without the need for data generation from expensive downhole samples. This research also led to a more powerful reservoir simulator that can be used by E&P companies to predict asphaltene precipitation in reservoirs and help with the design of primary and secondary recovery processes on their desktops or clusters of computers to solve E&P challenges of the future.
Accurate Streamline Tracing on Three-Dimensional Tetrahedral and Hexahedral Grids
Authors: Matringe Sébastien F.
Published: September 2008

Modern reservoir simulation grids are geometrically complex (distorted or unstructured grids) and often populated with tensor permeabilities. The solution of the flow problem on these advanced grids requires accurate finite volume methods such as the multipoint flux approximation (MPFA) schemes. Existing streamline tracing algorithms do not preserve the accuracy of the MPFA solutions and therefore represent a source of errors for the streamline method.

Very recently, MPFA methods have been related to mixed finite element methods (MFEM) on 3D tetrahedral and hexahedral grids. This link equips MPFA with a new mathematical framework that we exploit to design a new streamline tracing method. Our approach was already used successfully in 2D and this paper presents the extension to 3D of the previous work by the authors.

In the new method, the velocity field is interpolated from the MPFA subfluxes using mixed finite element velocity shape functions. The streamlines are then integrated to arbitrary accuracy. The method is the natural extension of Pollock's (1988) tracing method for general tetrahedral or hexahedral grids. The new method presents two major advantages over the streamline tracing methods developed for MPFA by Prévost et al.1 and Hægland et al.2 First, our algorithm provides more accurate streamlines and second, the direct interpolation of the velocity from the MPFA subfluxes avoids the expensive flux postprocessing used by the other methods. After a detailed description of the theory and implementation of our streamline tracing method, we use challenging test cases to compare its accuracy and efficiency to other existing streamline tracing methods.
Constitution, Government and Democracy in Brazil
Authors: Couto Cláudio G. , Arantes Rogério B.
Published: September 2008

With the intention of contributing to the comparative studies about the impact that constitutions have on the ordinary democratic political process, this article analyses the profile of the Brazilian 1988 constitution based on its contents and discerning to what extent the constitutional text - as well as its constitutional provisions - comprises public policies. Our hypothesis is that a constitutional text that contains many public policies (like the Brazilian one) is more prone to become a target of changing initiatives. The Brazilian constitution of 1988 presents a high rate of constitutional amending, with 62 amendments in twenty years (3.1 amendments per year); most of them sponsored by the Executive branch, aiming at implementing public policies. Due to the fact that the post-1988 governmental platforms have abided a ``constituent agenda," the comprehension of the current Brazilian political dynamics (especially the relationship between branches of government) passes necessarily through the understanding of Brazilian constitutional features. Such analysis has been done by means of a ``Constitutional Analysis Methodology" (Metodologia de Análise Constitucional - MAC) developed by the authors, which allows for the interpretation of the meaning of the constitutional provisions as well as their measurement.
Unusual intragenomic and interspecific variability of Geobacillus 16S-23S rRNA internal transcribed spacers
Authors: Kuisiene Nomeda , Raugalas Juozas , Chitavichius Donaldas
Published: September 2008

The aim of this study was to evaluate the inter-and intraspecific as well as intragenomic variability of Geobacillus 16S–23S rRNA internal transcribed spacers without tRNA genes and to compare these sequences with sequences bearing tRNA genes. In this study the structural analysis was performed in a unique way because the length and the sequence of the structural blocks were adjusted to fit the structure of 16S–23S rRNA internal transcribed spacers of five different Geobacillus species. Our study demonstrated the mosaic-like structure of 16S–23S rRNA internal transcribed spacers in Geobacillus. Some characteristics of these spacers of geobacilli were not previously reported for other bacteria: unusually short conserved sequence in the 5′ end region, some identical conserved blocks in both 5′ and 3′ regions of 16S–23S rRNA internal transcribed spacers, the same sequence blocks in both 16S–23S and 23S–5S rRNA intergenic spacers. Our study demonstrated quite uniform arrangement of the sequence blocks in Geobacillus thermodenitrificans. This species diverged early in the phylogenetic tree of the genus Geobacillus. For the phylogenetically recent species Geobacillus kaustophilus and Geobacillus lituanicus the low inter-and intraspecific, but high intragenomic variability, as a consequence of recent phylogenetic events, was established.
Editor's Foreword
Authors: Iwama Kazuo
Published: September 2008

The scope of the topic "algorithms" has been eminently expanded over the past two decades.[...]
The Second Entropy: A Variational Principle for Time-dependent Systems
Authors: Attard Phil
Published: September 2008

The fundamental optimization principle for non-equilibrium thermodynamics is given. The second entropy is introduced as the quantity that is maximised to determine the optimum state of a non-equilibrium system. In contrast, the principles of maximum or minimum dissipation, which have previously been proposed by Onsager, Prigogine, and others as the variational principle for such systems, are shown to be incapable of fulfilling that rôle.
Qualitative Picture of Scaling in the Entropy Formalism
Authors: Behringer Hans
Published: September 2008

The properties of an infinite system at a continuous phase transition are characterised by non-trivial critical exponents. These non-trivial exponents are related to scaling relations of the thermodynamic potential. The scaling properties of the singular part of the specific entropy of infinite systems are deduced starting from the well-established scaling relations of the Gibbs free energy. Moreover, it turns out that the corrections to scaling are suppressed in the microcanonical ensemble compared to the corresponding corrections in the canonical ensemble.
Travel Motivations and Satisfaction: A Case of National Cultural Festival-Goers in Korea
Authors: Kim Kakyom
Published: September 2008

Information about motivation related to travel behavior allows marketers to better understand and predict individuals' decision making. This study identified underlying motivational factors of national cultural festival-goers in Korea and classified distinct travel groups attending
the festival. Factor analysis determined eight reliable motivational factors and cluster analysis suggested three heterogeneous travel groups. To validate the travel groups, analysis of variance (ANOVA) and discriminant analysis were performed, followed by the chi-square statistic. The findings
support that significant differences exist in the motivational factors, overall satisfaction levels, annual income, and duration of the visit across the three travel groups. Practical implications are discussed for festival marketers to promote cultural festival visits.
Community-Defined Cultural and Ecological Tourism Framework: Potential Applications in Romania's Orastie Zone
Authors: Sasidharan Vinod , Hall Marilyn E.
Published: September 2008

The intense tourism initiatives currently being implemented at the national level in Romania have the potential to rejuvenate the country's rural economies. Although the national goal to utilize tourism as an economic development strategy in rural areas is both viable and timely, it
is crucial for the Romanian government to adopt sustainable rural tourism practices incorporating local community-identified needs and viewpoints relating to tourism development. This article elucidates one such attempt at identifying the needs and concerns of a cross-section of community
stakeholders, from the Orastie region of Romania, regarding appropriate forms of tourism development in their community and surrounding areas. In early 2004, a series of community meetings and focus groups was held in Orastie, as part of an NGO-facilitated rural tourism consultation project
for the region. Although the local governments and community members of the area were highly enthusiastic regarding Orastie's tourism potential, no clear guidance for sustainable tourism development was available until a tourism planning framework was developed by the consultation team. From
this study, it may be inferred that, for successful sustainable rural tourism development to occur, it is vital for local governments to enhance local empowerment through involvement of community members in the tourism planning and decision-making process.
Population structure and genetic diversity of New World maize races assessed by DNA microsatellites
Authors: Vigouroux Yves , Glaubitz Jeffrey C. , Matsuoka Yoshihiro , Goodman Major M. , Sánchez G. Jesús , Doebley John
Published: September 2008

Because of the economic importance of maize and its scientific importance as a model system for studies of domestication, its evolutionary history is of general interest. We analyzed the population genetic structure of maize races by genotyping 964 individual plants, representing almost the entire set of ∼350 races native to the Americas, with 96 microsatellites. Using Bayesian clustering, we detected four main clusters consisting of highland Mexican, northern United States (US), tropical lowland, and Andean races. Phylogenetic analysis indicated that the southwestern US was an intermediary stepping stone between Mexico and the northern US. Furthermore, southeastern US races appear to be of mixed northern flint and tropical lowland ancestry, while lowland middle South American races are of mixed Andean and tropical lowland ancestry. Several cases of post‐Columbian movement of races were detected, most notably from the US to South America. Of the four main clusters, the highest genetic diversity occurs in highland Mexican races, while diversity is lowest in the Andes and northern US. Isolation by distance appears to be the main factor underlying the historical diversification of maize. We identify highland Mexico and the Andes as potential sources of genetic diversity underrepresented among elite lines used in maize breeding programs.
Plant species diversity and composition of wetlands within an upland forest
Authors: Flinn Kathryn M. , Lechowicz Martin J. , Waterway Marcia J.
Published: September 2008

Though often overlooked, small wetlands in an upland matrix can support diverse plant communities that increase both local and regional species richness. Here we characterize the full range of wetland vegetation within an upland forest landscape and compare the diversity and composition of different wetland plant communities. In an old‐growth forest reserve in southern Quebec, Canada, we sampled wet habitats including lakeshores, permanent and seasonal ponds, swamps, glades, and streamsides. We used clustering, indicator species analysis, and nonmetric multidimensional scaling ordination to identify and compare vegetation types. The wetlands contained 280 species of vascular plants, 45% of the reserve's flora, in only 1.1% of its area. Local diversity averaged 24 ± 0.7 species per 7 m2, much higher than in the surrounding upland forests. Plant communities sorted into five types, whose strongest indicator species wereOsmunda regalis, Glyceria striata, O. cinnamomea, Deparia acrostichoides, andMatteuccia struthiopteris, respectively. Both local species richness and compositional variation among sites differed among the vegetation types. By combining species representative of the region's major wetlands with species from the upland forest matrix, the plant assemblages of these wetlands make disproportionately important contributions to landscape‐level diversity.
Phylogenetics of neotropical Platymiscium (Leguminosae: Dalbergieae): systematics, divergence times, and biogeography inferred from nuclear ribosomal and plastid DNA sequence data
Authors: Saslis‐Lagoudakis Charilaos , Chase Mark W. , Robinson Daniel N. , Russell Stephen J. , Klitgaard Bente B.
Published: September 2008

Platymiscium is a neotropical legume genus of forest trees in the Pterocarpus clade of the pantropical “dalbergioid” clade. It comprises 19 species (29 taxa), distributed from Mexico to southern Brazil. This study presents a molecular phylogenetic analysis of Platymiscium and allies inferred from nuclear ribosomal (nrITS) and plastid (trnL, trnL‐F and matK) DNA sequence data using parsimony and Bayesian methods. Divergence times are estimated using a Bayesian method assuming a relaxed molecular clock (multidivtime). Within the Pterocarpus clade, new sister relationships are recovered: Pterocarpus + Etaballia, Inocarpus + Tipuana and Paramachaerium + Maraniona. Our results support monophyly of Platymiscium, which is resolved into three major clades, each with distinct geographic ranges and ecological preferences. Diversification in Platymiscium has been driven by habitat fragmentation, invasion of novel geographic regions, and ecological diversification, revealing general patterns of diversification in the neotropics. We hypothesize that Platymiscium arose in dry habitats of South America and radiated northward. The Amazon basin was invaded twice both within the last 5.6 My and Central America twice before the closure of the Isthmus of Panama. Divergence times of the P. pubescens complex, restricted to seasonally dry tropical forests of South America, support pre‐Pleistocene divergence in this biome.
Recent Applications of Conjugated Polyelectrolytes in Optoelectronic Devices
Authors: Hoven Corey V. , Garcia Andres , Bazan Guillermo C. , Nguyen Thuc‐Quyen
Published: September 2008

Conjugated polyelectrolytes comprise an electronically delocalized backbone with pendant groups bearing ionic functionalities. Important new developments regarding their use to improve charge injection from metallic electrodes into organic semiconductors, a key requirement in emissive devices, have recently appeared. This article provides an overview of recent studies concerning the basic properties of conjugated polyelectrolytes as a function of molecular structure, and of optoelectronic devices with conjugated polyelectrolytes as essential functional components. Processes where more insightful mechanistic understanding is needed and areas of opportunity are discussed.
Hollow Micro‐/Nanostructures: Synthesis and Applications
Authors: Lou Xiong Wen (David) , Archer Lynden A. , Yang Zichao
Published: September 2008

Hollow micro‐/nanostructures are of great interest in many current and emerging areas of technology. Perhaps the best‐known example of the former is the use of fly‐ash hollow particles generated from coal power plants as partial replacement for Portland cement, to produce concrete with enhanced strength and durability. This review is devoted to the progress made in the last decade in synthesis and applications of hollow micro‐/nanostructures. We present a comprehensive overview of synthetic strategies for hollow structures. These strategies are broadly categorized into four themes, which include well‐established approaches, such as conventional hard‐templating and soft‐templating methods, as well as newly emerging methods based on sacrificial templating and template‐free synthesis. Success in each has inspired multiple variations that continue to drive the rapid evolution of the field. The Review therefore focuses on the fundamentals of each process, pointing out advantages and disadvantages where appropriate. Strategies for generating more complex hollow structures, such as rattle‐type and nonspherical hollow structures, are also discussed. Applications of hollow structures in lithium batteries, catalysis and sensing, and biomedical applications are reviewed.
Type II autosomal recessive cutis laxa: Report of another patient and molecular studies concerning three candidate genes
Authors: Scherrer Daniel Zanetti , Alexandrino Fabiana , Cintra Maria Letícia , Sartorato Edi Lúcia , Steiner Carlos Eduardo
Published: September 2008

Cutis laxa is a rare disorder of connective tissue in which the skin sags excessively, giving the individual an aged appearance. In the present study we analyzed three unrelated families with type II autosomal recessive cutis laxa for mutations in three genes implicated in other forms of cutis laxa; LOX, FBLN4, and FBLN5 genes. Two individuals have been previously reported, and the third case is described in detail. No causative mutations were identified. © 2008 Wiley‐Liss, Inc.
The Matthew effect defined and tested for the 100 most prolific economists
Authors: Tol Richard S.J.
Published: September 2008

The Matthew effect has that recognition is bestowed on researchers of already high repute. If recognition is measured by citations, this means that often‐cited papers or authors are cited more often. I use the statistical theory of the growth of firms to test whether the fame of papers and authors indeed exhibits increasing returns to scale, and confirm this hypothesis for the 100 most prolific economists.
Influence of measurement errors and deviations from Tully‐Fisher relationship on multipole structure of bulk galaxy motion
Authors: Parnovsky S.L. , Parnowski A.S.
Published: September 2008

The velocity field of large‐scale non‐Hubble galaxy motion recovered from peculiar velocities of spiral galaxies is distorted due to measurement errors and deviations from Tully‐Fisher relationship. To figure out how this affects the multipole structure we use the Monte‐Carlo approach and simulate errors and deviations. We use the galaxies from the Revised Flat Galaxy Catalogue subsample and the generalized Tully‐Fisher relationship in the ‘H I line width–angular diameter’ version. The analysis of the multipole structure has shown that the dipole velocity component (bulk motion) is underestimated, and the characteristic values of the quadrupole component are overestimated. The directions of the quadrupole component's eigenvectors can be determined precisely enough. Typical deviation angles of bulk motion apices lie between 17 and 40.. The main input is caused by errors in the measurement of the angular diameter. The probability of the quadrupole component being incidental can be estimated at the 4 per cent level. For the octopole component, it can be estimated at the 7–10 per cent level. This is essentially higher than the estimations less than 1 per cent due to the Fisher test. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An interpretation of rapid changes in the magnetic field associated with solar flares
Authors: Oreshina I.V. , Somov B.V.
Published: September 2008

The energy source of a flare is the magnetic field in the corona. A topological model of the magnetic field is used here for interpreting the recently discovered drastic changes in magnetic field associated with solar flares. The following observational results are self‐consistently explained: (1) the transverse field strength decreases at outer part of active regions and increases significantly in their centers; (2) the center‐of‐mass positions of opposite magnetic polarities converge towards the magnetic neutral line just after flares onset; (3) the magnetic flux of active regions decreases steadily during the course of flares. For X‐class flares, almost 50% events show such changes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The main sequence from F to K stars of the solar neighbourhood in SDSS colours
Authors: Just A. , Jahreiß H.
Published: September 2008

For an understanding of Galactic stellar populations in the SDSS filter system well defined stellar samples are needed. The nearby stars provide a complete stellar sample representative for the thin disc population. We compare the filter transformations of different authors applied to the main sequence stars from F to K dwarfs to SDSS filter system and discuss the properties of the main sequence. The location of the mean main sequence in colour‐magnitude diagrams is very sensitive to systematic differences in the filter transformation. A comparison with fiducial sequences of star clusters observed in g ′, r ′, and i ′ show good agreement. Theoretical isochrones from Padua and from Dartmouth have still some problems, especially in the (r – i) colours. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The problem of phase mixed shear Alfvén waves in the solar corona revisited
Authors: Mocanu G. , Marcu A. , Ballai I. , Orza B.
Published: September 2008

The problem of phase mixing of shear Alfvén waves is revisited taking into account dissipative phenomena specific for the solar corona. In regions of space plasmas where the dynamics is controlled by the magnetic field, transport coefficients become anisotropic with transport mechanism having different behavior and magnitude depending on the orientation with respect to the ambient magnetic field. Taking into account realistic values for dissipative coefficients we obtain that the previous results derived in context of torsional Alfvén wave phase mixing are actually heavily underestimated so phase mixing cannot be used to explain the damping of torsional Alfvén waves and heating of open coronal structures. The presented results indicate that in order for phase mixing to still be a viable mechanism to explain heating or wave damping unrealistic assumptions have to be made. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐resolution observations of extremely bright penumbral grains
Authors: Denker C. , Tritschler A. , Deng N.
Published: September 2008

We observed a cluster of extremely bright penumbral grains located at the inner limb‐side penumbra of the leading sunspot in active region NOAA 10892. The penumbral grains in the cluster showed a typical peak intensity of 1.58 times the intensityI0of the granulation surrounding the sunspot. The brightest specimen even reached values of 1.8–2.0I0, thus, exceeding the temperatures of the brightest granules in the immediate surroundings of the sunspot. We find that the observed sample of extremely bright penumbral grains is an intermittent phenomenon, that disappears on time scales of hours. Horizontal flow maps indicating proper motions reveal that the cluster leaves a distinct imprint on the penumbral flow field. We find that the divergence line co‐located with the cluster is displaced from the middle penumbra closer towards the umbra and that the radial outflow velocities are significantly increased to speeds in excess of 2 km s–1. The extremely bright penumbral grains, which are located at the inner limb‐side penumbra, are also discernible in offband Hαimages down to Hα± 0.045 nm. We interpret the observations in the context of themoving flux tubemodel arguing that hotter than normal material is rapidly ascending along the inner footpoint of the embedded flux tube, i.e., the ascending hot material is the cause of the extremely bright penumbral grains. This study is based on speckle‐reconstructed broad‐band images taken at 600 nm and chromospheric Hαobservations obtained with two‐dimensional spectroscopy. All data were taken with adaptive optics under very good seeing conditions at the Dunn Solar Telescope, National Solar Observatory/Sacramento Peak, New Mexico on 2006 June 10. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrogen production by photoautotrophic sulfur‐deprived Chlamydomonas reinhardtii pre‐grown and incubated under high light
Authors: Tolstygina Irina V. , Antal Taras K. , Kosourov Sergey N. , Krendeleva Tatyana E. , Rubin Andrey B. , Tsygankov Anatoly A.
Published: September 2008

We have previously demonstrated that Chlamydomonas reinhardtii can produce hydrogen under strictly photoautotrophic conditions during sulfur deprivation [Tsygankov et al. (2006); Int J Hydrogen Energy 3:1574–1584]. The maximum hydrogen photoproduction was achieved by photoautotrophic cultures pre‐grown under a low light regime (25 µE m−2 s−1). We failed to establish sustained hydrogen production from cultures pre‐grown under high light (100 µE m−2 s−1). A new approach for sustained hydrogen production by these cultures is presented here. Assuming that stable and reproducible transition to anerobiosis as well as high starch accumulation are important for hydrogen production, the influence of light intensity and dissolved oxygen concentration during the oxygen evolving stage of sulfur deprivation were investigated in cultures pre‐grown under high light. Results showed that light higher than 175 µE m−2 s−1 during sulfur deprivation induced reproducible transition to anerobiosis, although the total amount of starch accumulation and hydrogen production were insignificant. The potential PSII activity measured in the presence of an artificial electron acceptor (DCBQ) and an inhibitor of electron transport (DBMIB) did not change in cultures pre‐grown under 20 µE m−2 s−1 and incubated under 150 µE m−2 s−1 during sulfur deprivation. In contrast, the potential PSII activity decreased in cultures pre‐grown under 100 µE m−2 s−1 and incubated under 420 µE m−2 s−1. This indicates that cultures grown under higher light experience irreversible inhibition of PSII in addition to reversible down regulation. High dissolved O2 content during the oxygen evolving stage of sulfur deprivation has a negative regulatory role on PSII activity. To increase hydrogen production by C. reinhardtii pre‐grown under 100 µE m−2 s−1, cultures were incubated under elevated PFD and decreased oxygen pressure during the oxygen evolving stage. These cultures reproducibly reached anaerobic stage, accumulated significant quantities of starch and produced significant quantities of H2. It was found that elevation of pH from 7.4 to 7.7 during the oxygen producing stage of sulfur deprivation led to a significant increase of accumulated starch. Thus, control of pH during sulfur deprivation is a possible way to further optimize hydrogen production by photoautotrophic cultures. Biotechnol. Bioeng. 2009;102: 1055–1061. © 2008 Wiley Periodicals, Inc.
Complete versus incomplete revascularization in patients with multivessel disease undergoing percutaneous coronary intervention with drug‐eluting stents
Authors: Tamburino Corrado , Angiolillo Dominick J. , Capranzano Piera , Dimopoulos Konstantinos , La Manna Alessio , Barbagallo Rossella , Tagliareni Francesco , Mangiafico Sarah , Guzman Luis A. , Galassi Alfredo R. , Bass Theodore A.
Published: September 2008

Objectives:

To investigate the long‐term prognostic implications of complete versus incomplete revascularization in multivessel coronary artery disease (MVD) patients undergoing percutaneous coronary intervention (PCI) with drug‐eluting stent (DES).

Background:

Coronary artery bypass grafting (CABG) in patients with MVD provides better outcomes when complete revascularization is achieved. There is a paucity of data on the outcomes of complete versus incomplete revascularization of MVD patients undergoing PCI, and currently there is no data available with DES.

Methods:

Patients with MVD undergoing PCI with DES (sirolimus‐ or paclitaxel‐eluting stent) were included. Comparisons of long‐term outcomes between completely versus incompletely revascularized patients were made. The primary outcome measure was the composite of cardiac death, nonfatal myocardial infarction (MI), or any revascularization. Secondary endpoints were the components of the composite endpoint.

Results:

A total of 508 patients were considered for this analysis: 212 (41.7%) and 296 (58.3%) had complete and incomplete revascularization, respectively. The median follow‐up was 27.0 (interquartile range: 23.0–37.1) months. After adjusting for baseline characteristics, the hazard ratio (HR, 95% confidence interval) for complete revascularization was 0.43 (0.29–0.63,P< 0.0001) for the primary composite endpoint. Complete revascularization was associated with better outcomes for components of the composite endpoint: 0.37 (0.15–0.92,P= 0.03) for cardiac death, 0.34 (0.16–0.75P= 0.008) for the composite of cardiac death or MI and 0.45 (0.29–0.69,P= 0.0003) for any repeat revascularization. This association was confirmed in a propensity‐matched population.

Conclusions:

Complete revascularization with DES of MVD patients is associated with lower rates of long‐term adverse events. © 2008 Wiley‐Liss, Inc.
Prevention and management of transcatheter balloon‐expandable aortic valve malposition
Authors: Ali Abdullah M. Al , Altwegg Lukas , Horlick Eric M. , Feindel Christopher , Thompson Christopher R. , Cheung Anson , Carere Ronald G. , Humphries Karin , Ye Jian , Masson Jean‐Bernard , Webb John G.
Published: September 2008

Objectives:

Early clinical outcomes in selected high‐risk patients undergoing catheter‐based aortic valve replacement (AVR) compare favorably with conventional surgical AVR. Improved understanding of the mechanisms of success and failure of transcatheter AVR will likely improve outcomes further. To this end, we examined our experience during the developmental phases of transcatheter AVR and describe the causes and management of prosthetic valve malposition.

Methods:

Transcatheter balloon‐expandable AVR was performed in 170 patients at two centers. Malposition was defined as prosthetic valve implantation in a location other than within the native valve. Patients were prospectively identified and followed as part of an ongoing database.

Results:

Valve malposition occurred in 9 of 170 patients (5.3%). Final position was supravalvular in eight of nine cases. In all cases, embolization to the ascending aorta occurred within a few cardiac cycles following deployment. Importantly, late embolization was not observed. In most cases, the prosthesis was uneventfully repositioned in the more distal aorta. Positioning was subvalvular in one patient (0.6%), resulting in a severe regurgitation with residual native valve stenosis. Implantation of a second transcatheter valve was attempted in six patients and was successful in all. Conventional AVR was performed in two patients, with early mortality in one. At late follow‐up (mean 412 days), seven of nine patients remain alive (78%) with a functioning prosthesis and relief of aortic stenosis.

Conclusions:

Malposition of current balloon‐expandable aortic valves is a largely preventable complication. An improved understanding of the procedure will likely minimize this possibility and mitigate the consequences should malposition occur. © 2008 Wiley‐Liss, Inc.
Single pediatric center experience with multiple device implantation for complex secundum atrial septal defects
Authors: Bramlet Matthew T. , Hoyer Mark H.
Published: September 2008

Objectives: We analyzed the efficacy and complications of placing multiple transcatheter devices to correct complex ASD in a primarily pediatric population. Background: Limited pediatric information exists regarding the safety and efficacy of using multiple devices for secundum atrial septal defects (ASD) when multiple defects are present. Methods: Cath lab, echo, and clinical data were reviewed for 238 patients who underwent device closure of secundum ASD from 2000 to 2007 at a single pediatric center. Of those requiring multiple devices (n = 15), residual shunting and complications were assessed. Results: 238 patients (mean age 12 yrs; 80% < 16 yrs) underwent transcatheter ASD closure. 34 (14%) had multiple ASD, but only 15 received multiple devices (2 devices in 14 and 3 devices in 1). The mean age and weight (12 yrs; 35 kg) represent a younger population than previously reported. Only 3 were > 15 yrs, with a median age of 10.8 yrs (range 2–31). There was no compromise or obstruction to surrounding structures, and no device embolization or erosion was noted. A tiny thrombus was observed on the right sided screw of one device with no clinical sequelae. One patient (age 31 yrs) died at home 30 days post procedure from cardiac tamponade. Autopsy revealed the 3 intact devices in stable position without evidence of erosion. Latest available echo follow‐up for the group revealed functional resolution of atrial level shunting in all patients. Conclusion: Multiple devices can safely and effectively be implanted in the pediatric population to close complex ASD. © 2008 Wiley‐Liss, Inc.
Slipping into trance
Authors: Kirsch Irving , Mazzoni Giuliana , Roberts Kathrine , Dienes Zoltan , Hallquist Michael N. , Williams John , Lynn Steven Jay
Published: September 2008

It has been hypothesized that highly hypnotizable people spontaneously slip into trance when given imaginative suggestions without prior induction of hypnosis. We tested this in two studies. In Study 1, we examined state reports from ten highly suggestible students following the administration of a suggestion for altered colour perception. The suggestion was administered twice, once with and once without prior induction of hypnosis. Students reported equivalent perceptual changes with and without the induction of hypnosis, but reported being in a hypnotic state only when a hypnotic induction had been administered. In Study 2, participants received either a hypnotic induction or specific suggestions to not slip into hypnosis. Even under these circumstances, subjective responding was equivalent in both conditions and behavioural responding was only slightly higher in the ‘hypnosis’ condition. These data disconfirm the slipping‐into‐hypnosis hypothesis. Copyright © 2008 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.
Sex‐specific expression of SOX9 during gonadogenesis in the amphibian Xenopus tropicalis
Authors: El Jamil Anwar , Kanhoush Rasha , Magre Solange , Boizet‐Bonhoure Brigitte , Penrad‐Mobayed May
Published: September 2008

To investigate the role of SOX9 gene in amphibian gonadogenesis, we analyzed its expression during male and female gonadogenesis in Xenopus tropicalis. The results showed that in both sexes SOX9 mRNA and protein were first detectable after metamorphosis when the gonads were well differentiated and remained present until the adult stage. In the testis, SOX9 expression was restricted to the nucleus of Sertoli‐like cells, similarly to what has been observed in other vertebrates suggesting a conserved role in vertebrate testicular differentiation. In the ovary, in sharp contrast with what has been observed in all vertebrates examined so far, the SOX9 protein was localized in the cytoplasm of previtellogenic oocytes before being translocated into the nucleus of vitellogenic oocytes suggesting an unexpected role during oogenesis. These results suggest that the SOX9 gene may not be a sex‐determining gene in X. tropicalis and may play different functions in testicular and ovarian differentiation. Developmental Dynamics 237:2996–3005, 2008. © 2008 Wiley‐Liss, Inc.
Development of lymphatic vessels in mouse embryonic and early postnatal hearts
Authors: Juszyński Michał , Ciszek Bogdan , Stachurska Emilia , Jabłońska Anna , Ratajska Anna
Published: September 2008

We aimed to study the spatiotemporal pattern of lymphatic system formation in the embryonic and early postnatal mouse hearts. The first sign of the development of lymphatics are Lyve‐1–positive cells located on the subepicardial area. Strands of Lyve‐1–positive cells occur first along the atrioventricular sulcus of the diaphragmatic surface and then along the great arteries. Lumenized tubules appear, arranged in rows or in a lattice. They are more conspicuous in dorsal atrioventricular junction, along the major venous and coronary artery branches and at the base of the aorta and the pulmonary trunk extending toward the heart apex. At later stages, some segments of the lymphatic vessels are partially surrounded by smooth muscle cells. Possible mechanisms of lymphangiogenesis are: addition of Lyve‐1–positive cells to the existing tubules, elongation of the lymphatic lattice, sprouting and coalescence of tubules. We discuss the existence of various subpopulations of endothelial cells among the Lyve‐1–positive cells. Developmental Dynamics 237:2973–2986, 2008. © 2008 Wiley‐Liss, Inc.
Thyroid hormone–up‐regulated hedgehog interacting protein is involved in larval‐to‐adult intestinal remodeling by regulating sonic hedgehog signaling pathway in Xenopus laevis
Authors: Hasebe Takashi , Kajita Mitsuko , Shi Yun‐Bo , Ishizuya‐Oka Atsuko
Published: September 2008

Sonic hedgehog (Shh) was previously shown to be involved in the larval‐to‐adult remodeling of the Xenopus laevis intestine. While Shh is transcriptionally regulated by thyroid hormone (TH), the posttranscriptional regulation of Shh signaling during intestinal remodeling is largely unknown. In the present study, we focused on a role of the pan‐hedgehog inhibitor, hedgehog interacting protein (Hip), in the spatiotemporal regulation of Shh signaling. Using real‐time reverse transcriptase‐polymerase chain reaction and in situ hybridization, we show that Hip expression is transiently up‐regulated during both natural and TH‐induced metamorphosis and that Hip mRNA is localized in the connective tissue adjacent to the adult epithelial primordia expressing Shh. Interestingly, the expression of bone morphogenetic protein‐4, a Shh target gene, is hardly detectable where Hip is strongly expressed. Finally, we demonstrate that Hip binds to the N‐terminal fragment of processed Shh in vivo, suggesting that Hip suppresses Shh signaling through sequestering Shh. Developmental Dynamics 237:3006–3015, 2008. © 2008 Wiley‐Liss, Inc.
Inhibition of mammalian muscle differentiation by regeneration blastema extract of Sternopygus macrurus
Authors: Kim Hyun‐Jung , Archer Eric , Escobedo Norma , Tapscott Stephen J. , Unguez Graciela A.
Published: September 2008

Tissue regeneration through stem cell activation and/or cell dedifferentiation is widely distributed across the animal kingdom. By comparison, regeneration in mammals is poor and this may reflect a limited dedifferentiation potential of mature cells. Because mammalian myotubes can dedifferentiate in the presence of newt blastema extract, the present study tested the dedifferentiation induction capability of the blastema from the teleost Sternopygus macrurus (SmBE). Our in vitro data showed that SmBE did not induce cell cycle reentry of myonuclei in myotubes. Instead, SmBE caused myotubes to detach and time‐lapse imaging analyses characterized the cellular events before their detachment. Furthermore, SmBE enhanced myoblast proliferation and reversibly inhibited their differentiation. These data suggest the presence of protein factors in SmBE that regulate mammalian muscle physiology and differentiation, but do not support the conservation of a dedifferentiation induction capability by the blastema of S. macrurus. Developmental Dynamics 237:2830–2843, 2008. © 2008 Wiley‐Liss, Inc.
Drosophila SIN3 is required at multiple stages of development
Authors: Sharma Vishal , Swaminathan Aishwarya , Bao Riyue , Pile Lori A.
Published: September 2008

SIN3 is a component of a histone deacetylase complex known to be important for transcription repression. While multiple isoforms of SIN3 have been reported, little is known about their relative expression or role in development. Using a combination of techniques, we have determined that SIN3 is expressed throughout the Drosophila life cycle. The pattern of expression for each individual isoform, however, is distinct. Knock down of all SIN3 expression reveals a requirement for this protein in embryonic and larval periods. Taken together, the data suggest that SIN3 is required for multiple developmental events during the Drosophila life cycle. Developmental Dynamics 237:3040–3050, 2008. © 2008 Wiley‐Liss, Inc.
Kinetic and mechanical analysis of live tube morphogenesis
Authors: Cheshire Alan M. , Kerman Bilal E. , Zipfel Warren R. , Spector Alexander A. , Andrew Deborah J.
Published: September 2008

Ribbon is a nuclear Broad Tramtrack Bric‐a‐brac (BTB) ‐domain protein required for morphogenesis of the salivary gland and trachea. We recently showed that ribbon mutants exhibit decreased Crumbs and Rab11‐coincident apical vesicles and increased apical Moesin activity and microvillar structure during tube elongation. To learn how these molecular and morphological changes affect the dynamics of tubulogenesis, we optimized an advanced two‐photon microscope to enable high‐resolution live imaging of the salivary gland and trachea. Live imaging revealed that ribbon mutant tissues exhibit slowed and incomplete lumenal morphogenesis, consistent with previously described apical defects. Because Moesin activity correlates with cortical stiffness, we hypothesize that ribbon mutants suffer from increased apical stiffness during morphogenesis. We develop this hypothesis through mechanical analysis, using the advantages of live imaging to construct computational elastic and analytical viscoelastic models of tube elongation, which suggest that ribbon mutant tubes exhibit three‐ to fivefold increased apical stiffness and twofold increased effective apical viscosity. Developmental Dynamics 237:2874–2888, 2008. © 2008 Wiley‐Liss, Inc.
Development of diverse lateral line patterns on the teleost caudal fin
Authors: Wada Hironori , Hamaguchi Satoshi , Sakaizumi Mitsuru
Published: September 2008

The lateral line is composed of mechanoreceptors, the neuromasts, which are distributed over the body surfaces of fish. We examine the development of neuromast patterns on the caudal fins of medaka and zebrafish. In medaka, the terminal neuromast is established just prior to the caudal fin formation. The terminal neuromast subsequently gives rise to a cluster of accessory neuromasts. In zebrafish, the terminal neuromasts vary in terms of both number and position, and they achieve their final positions relative to the caudal fin structures through migration. Subsequently, they give rise to four lines of accessory neuromasts that extend along the caudal fin. We show that developmental processes similar to those observed in medaka and zebrafish may account for a large variety of patterns in other teleost species. These results establish terminal neuromast patterning as a new model for the study of the developmental mechanisms underlying diverse lateral line patterns. Developmental Dynamics 237:2889–2902, 2008. © 2008 Wiley‐Liss, Inc.
Perplexing Pax: From puzzle to paradigm
Authors: Blake Judith A. , Thomas Meghan , Thompson Jennifer A. , White Robert , Ziman Melanie
Published: September 2008

Pax transcription factors are critical for the development of the central nervous system (CNS) where they have a biphasic role, initially dictating CNS regionalization, while later orchestrating differentiation of specific cell subtypes. While a plethora of expression, misexpression, and mutation studies lend support for this argument and clarify the importance of Pax genes in CNS development, less well understood, and more perplexing, is the continued Pax expression in the adult CNS. In this article we explore the mechanism of action of Pax genes in general, and while being cognizant of existing developmental data, we also draw evidence from (1) adult progenitor cells involved in regeneration and tissue maintenance, (2) specific expression patterns in fully differentiated adult cells, and (3) analysis of direct target genes functioning downstream of Pax proteins. From this, we present a more encompassing theory that Pax genes are key regulators of a cell's measured response to a dynamic environment. Developmental Dynamics 237:2791–2803, 2008. © 2008 Wiley‐Liss, Inc.
Development of the proepicardium in Xenopus laevis
Authors: Jahr Maike , Schlueter Jan , Brand Thomas , Männer Jörg
Published: September 2008

The proepicardium (PE) is an embryonic progenitor cell population, which provides the epicardium, the majority of the cardiac interstitium, the coronary vasculature and possibly some cardiomyocytes. Recent studies have documented (1) the presence of bilaterally paired PE anlagen in several vertebrates, and (2) species‐specific differences in the fate of the left and right PE anlagen. Here, we document PE development in Xenopus laevis (stages 37–46). The PE appears at stage 41 in the form of a cone‐shaped accumulation of mesothelial cells covering the pericardial surface of the right horn of the sinus venosus. No such structure appears on the left sinus horn. At the end of stage 41, the tip of the PE establishes a firm contact with the developing ventricle. A secondary tissue bridge is established facilitating the transfer of PE cells to the heart. During stages 41–46, this tissue bridge is visible in vivo through the transparent body wall. Corresponding to the morphological data, the PE marker gene Tbx18 is expressed only on the right sinus horn suggesting a right‐sided origin of the PE. Left–right lineage tracing has confirmed this idea. These results show that Xenopus PE development proceeds in a bilaterally asymmetric pattern as previously observed in chicks. We speculate that asymmetric PE development is controlled by signals from left–right signaling pathways and that the PE is an indicator for right‐sidedness in Xenopus embryos. Xenopus might be a good model to uncover the role of left–right signaling pathways in the control of asymmetric PE development. Developmental Dynamics 237:3088–3096, 2008. © 2008 Wiley‐Liss, Inc.