bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ordered Pillar Array Structures of TiO2 by Nanoimprinting Using Anodic Porous Alumina as Molds
Authors: Yanagishita Takashi , Endo Takehide , Yamaguchi Yukiyasu , Nishio Kazuyuki , Masuda Hideki 
Published: February 2009

Abstract
Ordered pillar array structures of TiO2 were prepared by nanoimprinting process using ordered anodic porous alumina as a mold. The shape of the obtained pillars of TiO2 corresponded to that of the holes of anodic porous alumina used as a mold. The geometric structure of the TiO2 pillar array could be controlled by the condition of the formation of the anodic porous alumina molds.
Synthesis and Characterization of 2,3,7,8,12,13-Hexabromotruxene and Its Hexaaryl Derivatives
Authors: Lai Wen-Yong , He Qi-Yuan , Ma Zhun , Huang Wei 
Published: February 2009

Abstract
The first synthesis of 2,3,7,8,12,13-hexabromotruxene is reported. Its potential for further functionalization toward highly substituted conjugated materials is examined.
Controllable Fabrication of Multibranched TiO2 Nanotubes via a Two-step Anodization Method
Authors: Jin Zhen , Fei Guang Tao , Hu Xiao Ye , Xu Shao Hui , Zhang Li De 
Published: February 2009

Abstract
Multibranched TiO2 nanotubes have been controllably fabricated through a two-step anodization method. By tailoring the diameter ratio of the stem and branch accurate by multibranched, such as two-, three-, and four-branched, TiO2 nanotubes were obtained. The relationship of the diameter ratio and the branch number also has been discussed. This method provides a powerful approach to produce multibranched TiO2 nanotubes, which should have great potential application in future nanoscale systems.
On steady flows of incompressible fluids with implicit power-law-like rheology
Authors: Bulíček Miroslav , Gwiazda Piotr , Málek Josef , Świerczewska-Gwiazda Agnieszka 
Published: February 2009

AbstractWe consider steady flows of incompressible fluids with power-law-like rheology given by an implicit constitutive equation relating the Cauchy stress and the symmetric part of the velocity gradient in such a way that it leads to a maximal monotone (possibly multivalued) graph. Such a framework includes standard Navier–Stokes and power-law fluids, Bingham fluids, Herschel–Bulkley fluids, and shear-rate dependent fluids with discontinuous viscosities as special cases. We assume that the fluid adheres to the boundary.Using tools such as the Young measures, properties of spatially dependent maximal monotone operators and Lipschitz approximations of Sobolev functions, we are able to extend the results concerning large data existence of weak solutions to those values of the power-law index that are of importance from the point of view of engineering and physical applications.
A Collection of Ds Insertional Mutants Associated With Defects in Male Gametophyte Development and Function in Arabidopsis thaliana
Authors: Boavida Leonor C , Shuai Bin , Yu Hee-Ju , Pagnussat Gabriela C , Sundaresan Venkatesan , McCormick Sheila 
Published: February 2009

Abstract
Functional analyses of the Arabidopsis genome require analysis of the gametophytic generation, since ∼10% of the genes are expressed in the male gametophyte and ∼9% in the female gametophyte. Here we describe the genetic and molecular characterization of 67 Ds insertion lines that show reduced transmission through the male gametophyte. About half of these mutations are male gametophytic-specific mutations, while the others also affect female transmission. Genomic sequences flanking both sides of the Ds element were recovered for 39 lines; for 16 the Ds elements were inserted in or close to coding regions, while 7 were located in intergenic/unannotated regions of the genome. For the remaining 16 lines, chromosomal rearrangements such as translocations or deletions, ranging between 30 and 500 kb, were associated with the transposition event. The mutants were classified into five groups according to the developmental processes affected; these ranged from defects in early stages of gametogenesis to later defects affecting pollen germination, pollen tube growth, polarity or guidance, or pollen tube–embryo sac interactions or fertilization. The isolated mutants carry Ds insertions in genes with diverse biological functions and potentially specify new functions for several unannotated or unknown proteins.
The Impact of Sampling Schemes on the Site Frequency Spectrum in Nonequilibrium Subdivided Populations
Authors: Städler Thomas , Haubold Bernhard , Merino Carlos , Stephan Wolfgang , Pfaffelhuber Peter 
Published: February 2009

Abstract
Using coalescent simulations, we study the impact of three different sampling schemes on patterns of neutral diversity in structured populations. Specifically, we are interested in two summary statistics based on the site frequency spectrum as a function of migration rate, demographic history of the entire substructured population (including timing and magnitude of specieswide expansions), and the sampling scheme. Using simulations implementing both finite-island and two-dimensional stepping-stone spatial structure, we demonstrate strong effects of the sampling scheme on Tajima's D (DT) and Fu and Li's D (DFL) statistics, particularly under specieswide (range) expansions. Pooled samples yield average DT and DFL values that are generally intermediate between those of local and scattered samples. Local samples (and to a lesser extent, pooled samples) are influenced by local, rapid coalescence events in the underlying coalescent process. These processes result in lower proportions of external branch lengths and hence lower proportions of singletons, explaining our finding that the sampling scheme affects DFL more than it does DT. Under specieswide expansion scenarios, these effects of spatial sampling may persist up to very high levels of gene flow (Nm &gt; 25), implying that local samples cannot be regarded as being drawn from a panmictic population. Importantly, many data sets on humans, Drosophila, and plants contain signatures of specieswide expansions and effects of sampling scheme that are predicted by our simulation results. This suggests that validating the assumption of panmixia is crucial if robust demographic inferences are to be made from local or pooled samples. However, future studies should consider adopting a framework that explicitly accounts for the genealogical effects of population subdivision and empirical sampling schemes.
Sex-lethalFacilitates the Transition From Germline Stem Cell to Committed Daughter Cell in the Drosophila Ovary
Authors: Chau Johnnie , Kulnane Laura Shapiro , Salz Helen K 
Published: February 2009

AbstractIn Drosophila, the female-specific SEX-LETHAL (SXL) protein is required for oogenesis, but how Sxl interfaces with the genetic circuitry controlling oogenesis remains unknown. Here we use an allele of sans fille (snf) that specifically eliminates SXL protein in germ cells to carry out a detailed genetic and cell biological analysis of the resulting ovarian tumor phenotype. We find that tumor growth requires both Cyclin B and zero population growth, demonstrating that these mutant cells retain at least some of the essential growth-control mechanisms used by wild-type germ cells. Using a series of molecular markers, we establish that while the tumor often contains at least one apparently bona fide germline stem cell, the majority of cells exhibit an intermediate fate between a stem cell and its daughter cell fated to differentiate. In addition, snf tumors misexpress a select group of testis-enriched markers, which, remarkably, are also misexpressed in ovarian tumors that arise from the loss of bag of marbles (bam). Results of genetic epistasis experiments further reveal that bam's differentiation-promoting function depends on Sxl. Together these data demonstrate a novel role for Sxl in the lineage progression from stem cell to committed daughter cell and suggest a model in which Sxl partners with bam to facilitate this transition.
Heparin-Bonded Central Venous Catheters Do Not Reduce Thrombosis in Infants With Congenital Heart Disease: A Blinded Randomized, Controlled Trial
Authors: Anton Natalie , Cox Peter N. , Massicotte M. Patricia , Chait Peter , Yasui Yutaka , Dinyari P. Maria , Marzinotto Velma , Mitchell Lesley G. 
Published: February 2009

Background. Infants with congenital heart disease who require central venous lines are at increased risk of thrombosis. Heparin-bonded catheters provide protection from thrombotic events in some children. However, heparin-bonded catheters may not be as effective in infants ≤1 year old because of other potential risk factors (smaller vessel size, longer duration of catheter use). No studies have assessed the benefit of heparin-bonded catheters in such specific high-risk populations. The objective of this study was to assess the efficacy of heparin-bonded catheters for preventing thrombosis in infants aged ≤1 year with congenital heart disease.
Study Design. This study was designed as a randomized, controlled, blinded single-center trial. Infants ≤1 year old with congenital heart disease requiring a central venous line for clinical care were randomly assigned to receive either a heparin-bonded catheter or a standard non–heparin-bonded catheter. Catheters were visually indistinguishable. The primary outcome was incidences of both silent and clinically noticeable thrombosis confirmed by ultrasound. Ultrasounds were reviewed by a blinded central adjudication committee. Interim analysis was performed after enrollment of 97 patients.
Results. Eighty-seven patients were evaluable (41 of the patients were female). Thrombotic events occurred in 17 (42.5%) of 40 patients in the non–heparin-bonded catheter group and in 21 (44.7%) of 47 patients in the heparin-bonded catheters group. The study was stopped when the interim analysis showed convincing evidence for no difference between groups over the alternative hypothesis of 50% risk reduction.
Conclusions. Infants with congenital heart disease are at significant risk of both silent and clinically identified thrombosis. There seems to be no advantage in using heparin-bonded catheters in infants ≤1 year of age.
Correlation of Fluvial Rainbow Trout Spawning Life History with Severity of Infection by Myxobolus cerebralis in the Blackfoot River Basin, Montana
Authors: Pierce Ron , Podner Craig , Davidson Michael , Vincent E. Richard 
Published: February 2009

AbstractTo assess the exposure of Blackfoot River rainbow trout Oncorhynchus mykiss to the exotic parasite Myxobolus cerebralis, the causal agent of whirling disease, we investigated the spawning life histories of adult rainbow trout with respect to the distribution and severity of infection in spawning and early rearing areas in two distinct reaches of the Blackfoot River. Radiotelemetry confirmed that Blackfoot River rainbow trout express a fluvial life history and migrate from wintering sites within the Blackfoot River to spawning sites in the lower reaches of tributaries. Spawning peaked in late April, and fry emergence was estimated to occur within a narrow window of time in early July during the known period of high parasite exposure. However, the severity of infection varied between study reaches. Spawning of lower Blackfoot River rainbow trout was dispersed among the lowermost reaches of smaller, colder, higher‐gradient tributaries, most of which fell below our ability to detect infection. By contrast, a majority of the telemetered rainbow trout in the middle Blackfoot River spawned higher in the drainage and within a single, low‐gradient stream where fry emerged under infectious conditions. For fluvial rainbow trout, the risk of infection varies from the tributary to the subbasin scale and relates to the geographical arrangement and properties of the tributaries, the longitudinal relationship of the pathogen to spawning and early rearing areas, and the rate and timing of dispersing age‐0 fry to downstream parasite‐positive waters. Before the introduction of M. cerebralis, the middle Blackfoot River was identified as having recruitment limitations caused by winter mortality and anthropogenic activities. According to our results, riparian restoration and habitat enhancement with emphasis on migratory native fish within and upstream of the pathogen may buffer fish from the effects of the disease.
Nutrient Excretion Rates of Anadromous Alewives during Their Spawning Migration
Authors: Post David M. , Walters Annika W. 
Published: February 2009

AbstractExcretion is one of the processes through which anadromous fishes move marine‐derived nutrients into freshwater ecosystems, but no direct estimates of nutrient excretion rates by anadromous fish exist. We estimated the mass‐specific nutrient excretion rates of anadromous alewives Alosa pseudoharengus during their spring spawning migration into Bride Lake, Connecticut. Anadromous alewives excreted an average of 2.17 μg of phosphorus per gram of wet fish mass per hour and 24.71μg of nitrogen. The mean N:P ratio (by mass) of nutrient excretion was 11.7. Most of the nitrogen excreted was in the form of NH4+. Our results suggest that excretion by anadromous fish can affect local food webs and ecosystem function when ecosystems are relatively small and fish aggregate at high densities, such as at the peak of the spawning run.
Neoproterozoic microfossils from the northeastern margin of the East European Platform
Authors: Vorob'eva Nataliya G. , Sergeev Vladimir N. , Knoll Andrew H. 
Published: February 2009

The Kel'tminskaya-1 borehole, drilled along the northeastern margin of the East European Platform (EEP), reveals some 3,600 m of Neoproterozoic sedimentary rocks, mostly confined to the subsurface. The upper 1,000 m of the drilled section correlates with late Ediacaran Redkino and Kotlin successions on the EEP, whereas the lowermost 2,000 m can be related to pre-Sturtian (Upper Riphean) deposits in the Ural Mountains. In between lies the Vychegda Formation, a 600 m siliciclastic succession that has no counterpart in classic EEP stratigraphy.Vychegda microfossils can be separated into three assemblages. The upper part of the formation contains large, profusely ornamented acritarchs broadly comparable to those of the Ediacaran Complex Acanthomorph Palynoflora, including species of the generaAlicesphaeridium, Asterocapsoides, CavaspinaandTanariumconfined to Ediacaran-aged assemblages elsewhere. Diverse large acanthomorphs are known from Ediacaran strata around the world, but have not previously been recognized from the EEP, an absence attributed to a hiatus between the glacial Laplandian (>635 Ma) and Redkino (mostly <555 Ma) successions. The large acanthomorphic acritarchs record eukaryotic organisms with resting stages in their life cycles and likely include egg or diapause cysts of early animals. In contrast, the lower Vychegda assemblage, found in the basal 10 m of the succession, contains taxa typical of earlier Neoproterozoic successions. The middle assemblage contains only simple filaments and spheroidal acritarchs.The most parsimonious interpretation of Vychegda biostratigraphy is that pre-Marinoan rocks in the basal part of the formation are separated by a cryptic unconformity from early and middle Ediacaran deposits above. This interpretation is consistent with data from China and Australia, which indicate that the major paleontological transition to diverse ECAP assemblages took place within the Ediacaran Period and not in association with the preceding ice age. Vychegda acritarch assemblages thus contribute to a biostratigraphic model for the initial Ediacaran boundary.
Extrapolation of available acute and chronic toxicity test data to population-level effects for ecological risk management of chemicals
Authors: Lin Bin-Le , Meng Yaobin 
Published: February 2009

AbstractAn extrapolation approach is proposed using available acute (median lethal or effect concentration) and chronic (no-observed-effect concentration) toxicity test data at the organism level to derive a reference value contributing to the development of predicted-no-effect concentration on population persistence for population-level ecological risk assessment of chemicals. A matrix population model of wild medaka (Oryzias latipes) was employed as the tool to integrate the available organism-level toxicity test data on reproduction and survival into a finite population growth rate (λ) that provides information regarding the status of the population persistence. After demonstrating the approach using the acute and chronic toxicity test data of alcohol ethyxolate on fish to calculate the reference value defined as the concentration at λ = 1 (Cλ-1), the proposed approach was then evaluated by a comparison of the Cλ-1 value derived by the extrapolation approach to those Cλ-1 values calculated by two other approaches, in which different amounts of toxicity information contained in the same full life-cycle toxicity test data set on 4-nonylphenol were employed. It was concluded that this extrapolation approach is widely applicable and is promising for performing population-level ecological risk assessment on a more general basis that can support reasonable chemical management.
Pore-Scale Simulation of Dispersion in Porous Media
Authors: Garmeh Gholamreza , Johns Russell Taylor , Lake Larry W. 
Published: February 2009

Summary
Mixing of miscible gas with oil in a reservoir decreases the effective strength of the gas, which can adversely affect miscibility and recovery efficiency. The level of true mixing that occurs in a reservoir, however, is widely debated and often ignored in reservoir simulation in which very large grid blocks are used. Large grid blocks create artificially large mixing that can cause errors in predicted oil recovery.
This paper examines mixing that occurs in porous media by solving for single-phase flow in a connected network of pores. We differentiate between true mixing that can reduce the effective strength of a miscible gas or surfactant from apparent mixing caused by convective spreading. This work differs from network models in that we directly solve the Navier-Stokes equation and the convection-diffusion equation to determine the velocities and concentrations at any location within the pores. Flow in series and layered heterogeneous porous media are modeled through use of many grains in different arrangements. We consider slug, continuous, and partial injection as well as echo tests (single-well tracer tests) and transmission tests (interwell tracer tests). We match the concentrations from the pore-scale simulations to the analytical convection-dispersion solution that includes both transverse- and longitudinal-dispersion coefficients.
The results show that for flow in series and in layers, echo- and transmission-longitudinal dispersivities become equal and reach an asymptotic value if complete mixing over a cross section perpendicular to flow has occurred. In practice, the asymptotic value of dispersivity may never be reached, depending on pattern-scale heterogeneity and well spacing. Transverse-dispersion coefficients also are scale dependent, but they decrease with traveled distance. We further demonstrate that the classical Perkins-Johnston relationship between longitudinal-dispersion coefficient and fluid velocity is obtained. We conclude that echo dispersivities are reliable indicators of true mixing in porous media.
Accurate Corrosion Prediction Through an Integrated Approach
Authors: Bondos J. C. , Reddy R. V. , Pugh D. V. , Norman D. A. , Pacheco J. L. , Nelson J. L. 
Published: February 2009

Summary
The ability to optimize the use of carbon steel in corrosive service presents many economic advantages, including minimizing the use of expensive corrosion-resistant alloys (CRAs), reducing well count by enabling optimized large-bore completions, and eliminating unnecessary offshore pipelines and facilities. An integrated approach to corrosion modeling and testing can enable reliable extension of carbon steel application.
The integrated approach to predicting corrosion has five primary elements:
Rigorously establish the environmental conditions by conducting thermodynamic and compositional hydraulic analyses, and characterize how these conditions are expected to change over time. Identify and model the local environmental conditions and the types of corrosion that are expected to occur (e.g., weight loss, pitting, environmental cracking), including sensitivity and upset cases. Conduct realistic corrosion tests under the identified field conditions by simulating brine chemistry, dissolved acid gas concentrations, hydrocarbon effects, fluid shear stresses, and flow regimes in appropriate laboratory equipment. Specialized laboratory test apparatus, such as a large-diameter sour multiphase flow loop and large-volume high-pressure high-temperature autoclave test cells, has been designed and constructed to ensure proper replication of field conditions. Mathematically extrapolate the results of the laboratory tests to the field, enabling calculation of expected tubular life. Conduct life-cycle cost analysis.
This paper will describe how this integrated approach to predicting corrosion has been used to evaluate the use of carbon steel in oil and gas production environments. Emphasis will be placed on the prediction of pitting corrosion in H2S-containing environments.