bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Arterial Calcification in Adiponectin-Deficient Mice: Adiponectin Regulates Arterial Calcification
Authors: Luo Xiang-Hang , Zhao Li-Ling , Yuan Ling-Qing , Wang Min , Xie Hui , Liao Er-Yuan 
Published: March 2009

Abstract
Arterial calcification is common, but the mechanisms remain unclear. This study was undertaken to investigate the arterial calcification in adiponectin-deficient mice in vivo and the effects of adiponectin on cultured vascular smooth muscle cells in vitro. Alizarin red S staining was used to detect arterial calcification of adiponectin−/− mice. Alkaline phosphatase activity, osteocalcin secretion, and Runx2 protein expression were examined in cultured calcifying vascular smooth muscle cells (CVSMCs). The involved signal pathway was studied using a mitogen-activated protein kinase (MAPK) inhibitor and adiponectin receptor 1 (AdipoR1) siRNA. Adiponectin−/− mice developed slight arterial calcification after being fed with normal chow diet for 30 wk. Adenovirus-mediated supplement of adiponectin attenuated arterial calcification in these mice. On cultured CVSMCs, adiponectin inhibited ALP activity, osteocalcin secretion, Runx2 protein expression, and the formation of mineralized nodules. Adiponectin receptor 1 (AdipoR1) protein was detected in CVSMCs, and adiponectin activated p38 mitogen-activated protein kinase. Furthermore, inhibition of AdipoR1 expression or p38 activation reversed the effects of adiponectin on ALP activity. These results showed that adiponectin inhibited osteoblastic differentiation of CVSMCs through the AdipoR1/p38 signaling pathway. Our findings showed that adiponectin−/− mice developed arterial calcification, and this could be attributed to the loss of inhibitory action of adiponectin on osteoblastic differentiation of CVSMCs. It suggested that adiponectin plays a protective role against arterial calcification.
In-Service Embrittlement of the Pressure Vessel Welds at the Doel I And II Nuclear Power Plants
Authors: Gérard R , Fabry A , Van de Velde J , Puzzolante J-L , Verstrepen A , Van Ransbeeck T , Van Walle E 
Published: March 2009

In-service embrittlement of the welds at the Doel I and II pressure vessels displays an apparent “outlier” behaviour as compared to the predictions of US NRC Regulatory Guide 1.99 Rev.2. This issue is being addressed by a systematic R&D effort, supplementary to the mandatory surveillance programmes. The status of this effort is reviewed in this paper.
The anomalous trends can be outlined as follows. Extensive characterization of the chemical composition of representative test specimens reveals that these low nickel welds, although being nominally identical (same fabrication practice, heat treatment, microstructure,⋯), do feature an appreciable variability of their bulk copper content —covering a range of 0.13% to 0.35%. High copper Charpy-V weld specimens are however not available in the surveillance capsules. The variability could be identified only because the weld part of some HAZ (heat affected zone) Charpy-V specimens, as well as some tensile specimens, consist of the high copper melt. For the low copper contents, (0.13–0.18%), the 41 J Cv transition temperature shift, as obtained from seven capsules exposed in the neutron fluence range of 1 to 3.9 1019 n/cm2 (&gt;1 MeV), is rather constant, but significantly larger than predicted (by US NRC Regulatory Guide 1.99 rev.2).This has caused some concern on the upper bound shift to be adopted, given the possibility of higher copper content in the actual pressure vessel welds.
High copper samples were manufactured by applying the stud welding reconstitution technique to remnants of the HAZ specimens, and the results cannot be distinguished from the low copper data. Such insensitivity to copper,confirmed by tensile and hardness measurements, is at odds with current literature knowledge and with Regulatory guidelines. A further anomaly observed for this type of weld metal is an appreciable sensitivity to thermal ageing.
The surveillance results will be evaluated in accordance with the USNRC Regulatory guide-lines, and the embrittlement trends described above will be thoroughly evaluated from a micromechanical perspective, in the light of a high resolution microstructural investigation.
Multiple-Interval Mapping for Quantitative Trait Loci With a Spike in the Trait Distribution
Authors: Li Wenyun , Chen Zehua 
Published: March 2009

Abstract
For phenotypic distributions where many individuals share a common value—such as survival time following a pathogenic infection—a spike occurs at that common value. This spike affects quantitative trait loci (QTL) mapping methodologies and causes standard approaches to perform suboptimally. In this article, we develop a multiple-interval mapping (MIM) procedure based on mixture generalized linear models (GLIMs). An extended Bayesian information criterion (EBIC) is used for model selection. To demonstrate its utility, this new approach is compared to single-QTL models that appropriately handle the phenotypic distribution. The method is applied to data from Listeria infection as well as data from simulation studies. Compared to the single-QTL model, the findings demonstrate that the MIM procedure greatly improves the efficiency in terms of positive selection rate and false discovery rate. The method developed has been implemented using functions in R and is freely available to download and use.
Blue Light Induces Degradation of the Negative Regulator Phytochrome Interacting Factor 1 to Promote Photomorphogenic Development of Arabidopsis Seedlings
Authors: Castillon Alicia , Shen Hui , Huq Enamul 
Published: March 2009

AbstractPhytochrome interacting factors (PIFs) are nuclear basic helix-loop-helix (bHLH) transcription factors that negatively regulate photomorphogenesis both in the dark and in the light in Arabidopsis. The phytochrome (phy) family of photoreceptors induces the rapid phosphorylation and degradation of PIFs in response to both red and far-red light conditions to promote photomorphogenesis. Although phys have been shown to function under blue light conditions, the roles of PIFs under blue light have not been investigated in detail. Here we show that PIF1 negatively regulates photomorphogenesis at the seedling stage under blue light conditions. pif1 seedlings displayed more open cotyledons and slightly reduced hypocotyl length compared to wild type under diurnal (12 hr light/12 hr dark) blue light conditions. Double-mutant analyses demonstrated that pif1phyA, pif1phyB, pif1cry1, and pif1cry2 have enhanced cotyledon opening compared to the single photoreceptor mutants under diurnal blue light conditions. Blue light induced the rapid phosphorylation, polyubiquitination, and degradation of PIF1 through the ubi/26S proteasomal pathway. PIF1 interacted with phyA and phyB in a blue light-dependent manner, and the interactions with phys are necessary for the blue light-induced degradation of PIF1. phyA played a dominant role under pulses of blue light, while phyA, phyB, and phyD induced the degradation of PIF1 in an additive manner under prolonged continuous blue light conditions. Interestingly, the absence of cry1 and cry2 enhanced the degradation of PIF1 under blue light conditions. Taken together, these data suggest that PIF1 functions as a negative regulator of photomorphogenesis under blue light conditions and that blue light-activated phys induce the degradation of PIF1 through the ubi/26S proteasomal pathway to promote photomorphogenesis.
Mutations in Two Zinc-Cluster Proteins Activate Alternative Respiratory and Gluconeogenic Pathways and Restore Senescence in Long-Lived Respiratory Mutants ofPodospora anserina
Authors: Sellem Carole H , Bovier Elodie , Lorin Séverine , Sainsard-Chanet Annie 
Published: March 2009

AbstractIn Podospora anserina, inactivation of the respiratory chain results in a spectacular life-span extension. This inactivation is accompanied by the induction of the alternative oxidase. Although the functional value of this response is evident, the mechanism behind it is far from understood. By screening suppressors able to reduce the life-span extension of cytochrome-deficient mutants, we identified mutations in two zinc-cluster proteins, RSE2 and RSE3, which are conserved in other ascomycetes. These mutations led to the overexpression of the genes encoding the alternative oxidase and the gluconeogenic enzymes, fructose-1, 6 biphosphatase, and pyruvate carboxykinase. Both RSE2 and RSE3 are required for the expression of these genes. We also show that, even in the absence of a respiratory deficiency, the wild-type RSE2 and RSE3 transcription factors are involved in life-span control and their inactivation retards aging. These data are discussed with respect to aging, the regulation of the alternative oxidase, and carbon metabolism.
Work of Breathing and Different Levels of Volume-Targeted Ventilation
Authors: Patel Deena-Shefali , Sharma Atul , Prendergast Michael , Rafferty Gerrard F. , Greenough Anne 
Published: March 2009

OBJECTIVES. The objectives of this study were to determine the impact of different volume-targeted levels on the work of breathing and to investigate whether a level that reduced the work of breathing below that experienced during ventilatory support without volume targeting could be determined.
METHODS. The transdiaphragmatic pressure-time product, as an estimate of the work of breathing, was measured for 20 infants (median gestational age: 28 weeks) who were being weaned from respiratory support by using patient-triggered ventilation (either assist-control ventilation or synchronous intermittent mandatory ventilation). The transdiaphragmatic pressure-time product was measured first without volume targeting (baseline) and then at volume-targeted levels of 4, 5, and 6 mL/kg, delivered in random order. After each volume-targeted level, the infants were returned to baseline. Each step was maintained for 20 minutes.
RESULTS. The mean transdiaphragmatic pressure-time product was higher with volume targeting at 4 mL/kg in comparison with baseline, regardless of the patient-triggered mode. The transdiaphragmatic pressure-time product was higher at a volume-targeted level of 4 mL/kg in comparison with 5 mL/kg and at 5 mL/kg in comparison with 6 mL/kg. The mean work of breathing was below that at baseline only at a volume-targeted level of 6 mL/kg.
CONCLUSIONS. Low volume-targeted levels increase the work of breathing during volume-targeted ventilation. Our results suggest that, during weaning, a volume-targeted level of 6 mL/kg, rather than a lower level, could be used to avoid an increase in the work of breathing.
Thermal and Hydraulic Matrix-Fracture Interaction in Dual-Permeability Simulation
Authors: van Heel A. P. G. , Boerrigter P. M. , van Dorp J. J. 
Published: March 2009

Summary
The shape factor concept, originally introduced by Barenblatt in 1960, provides an elegant and powerful upscaling method for fractured reservoir simulation. The shape factor determines the fluid and heat transfer between matrix and fractures when there is a difference in pressure or temperature between matrix blocks and the surrounding fractures. An appropriate specification of the shape factor is therefore critical for accurate modeling.
Since its introduction, many different values for the shape factor have been proposed in the literature, among which the well-known Warren-Root and Kazemi shape factors. The aim of this paper is to show that the selection of the appropriate shape factor should not only depend on the “shape” and dimensions of matrix blocks, but should also take into consideration the character of the dominant underlying physical recovery mechanisms.
We will show that by taking into account the dominant physical recovery mechanism, the apparent discrepancies in the shape factor values reported in the literature can be overcome. We derive a general expression for the shape factor that not only captures existing shape factor expressions, but also allows extensions to recovery mechanisms requiring a dual permeability approach.
The paper is organized as follows. First, we briefly review the shape factors presented in the literature. We then derive the general expression for the (single-phase) matrix-fracture shape factor. Subsequently, we analytically derive a new shape factor that captures the transient in pressure/temperature diffusion processes. To compare and contrast the impact of the various shape factors, we consider three cases of increasing complexity. First, we consider pressure/temperature diffusion in a single 1D matrix block following a step change in the boundary conditions. Next, we consider isothermal gas/oil gravity drainage from a homogeneous stack. We compare fine-grid single-porosity simulations (in which the matrix is finely gridded and in which the fractures are explicitly represented) with coarse-grid dual-permeability simulations (in which the matrix-fracture interaction is modeled by shape factors). In the third step, we consider gas-oil gravity drainage of the same stack model, but now under steam injection. In this case, steam is injected at the top, and oil recovered from the base of the fracture system. Again, we compare fine-grid single-porosity simulations with coarse-grid dual-permeability simulations. We show that in this case, the constant (asymptotic) shape factor provides a good approximation to the heating of the stack. We will show, however, that with a constant (time-independent) shape factor, the initial fast heating of the matrix blocks cannot be captured. We show that the new transient shape factor, however, enables coarse-grid dual-permeability modeling of thermal recovery processes such that they reproduce fine-grid results.
Imaging Seismic Deformation Induced by Hydraulic Fracture Complexity
Authors: Maxwell S. C. , Waltman C. K. , Warpinski N. R. , Mayerhofer M. J. , Boroumand N. 
Published: March 2009

Summary
Microseismic mapping is extensively used in the Barnett Shale to map hydraulic fracture complexity associated with interactions of the stimulation with pre-existing fractures (fracs). Previous studies have indicated a fair correlation between the well performance and extent of the seismically active volume. However, in addition to this measure of the extent of the stimulated fracture network, the characteristics of this fracture network is also expected to impact the well performance. In particular, the fracture spacing is believed to be an important factor controlling the potential gas flow. In this paper, we use the density of the total seismic moment release (a robust measure of the microseism strength) as an indication of the seismic deformation that may correlate to the fracture density. The study uses a set of microseismic maps of hydraulic fracture stimulations, including cases in which the stimulated reservoir volume measured by the extent of the seismically active region poorly correlated with the well performance. Incorporating the seismic moment density to assess the fracture density with the network extent, an improved correlation with the well performance was observed.
New Trend in Oilfield Flow-Assurance Management: A Review of Thermal Insulating Fluids
Authors: Wang Xiaolan , Qu Qi , Javora Paul , Pearcy Rick 
Published: March 2009

Summary
Flow assurance has been one of the major considerations in deep-water completion design, in which undesired heat loss from production tubing contributes to the formation of gas hydrates and causes the deposition of paraffin and asphaltene materials. Traditionally, controlling annular heat loss has been achieved with the injection of steam, the application of silicate foam, the pressurization of the annulus with inert gas, the use of gelled oil as an insulating packer fluid, and the use of vacuum insulated tubing (VIT). Each of these applications, however, has drawbacks because of either its working mechanism or the higher cost associated with the technology.
To secure the insulation of the wellbore and to reduce heat transfer from the production tubing to the surrounding areas, various aqueous insulating fluid systems with superior thermal properties have been developed in recent years. Field applications of these fluids have demonstrated significant reduction in heat loss by reducing conduction and minimizing convection. These thermal insulating fluids have been implemented with great success in more than 75 deepwater riser and packer applications in the Gulf of Mexico (GOM) over the last several years. Case histories have demonstrated that installation of these water-based insulating fluids is an effective alternative to conventional insulation options and is becoming the preferred insulation method in many deep-water projects.
This paper will highlight the evolution of different insulating fluid systems and the field experience with each system. Proper testing methods relevant to oilfield flow assurance will be discussed and testing results for these fluids will be detailed. Field cases in the GOM will be summarized, and the effectiveness of these fluid systems will be demonstrated.
Lessons Learned From Energy Models: Iraq's South Rumaila Case Study
Authors: Kabir C. S , Al-Khayat N. I. , Choudhary M. K. 
Published: March 2009

Summary
Understanding reservoir behavior is the key to reservoir management. This study shows how energy modeling with rapid material-balance techniques, followed by numerical simulations with streamlines and finite-difference methods, aided understanding of reservoir-flow behavior. South Rumaila's long and elongated Zubair reservoir experiences uneven aquifer support from the western and eastern flanks. This uneven pressure support prompted injection in the weaker eastern flank to boost reservoir energy.
We learned that aquifer influx provided nearly 95% of the reservoir's energy in its 50-year producing life, with water injection contributing less than 5% of the total energy supply. The west-to-east aquifer energy support is approximately 29:1, indicating the dominance of aquifer support in the west. Streamline simulations with a 663,000-cell model corroborated many of the findings learned during the material-balance phase of this study. Cursory adjustments to aquifer properties led to acceptable match with pulse-neutron capture or PNC-derived-time-lapse oil/water contact (OWC) surfaces. This global-matching approach speeded up the history-matching exercise in that performance of most wells was reproduced, without resorting to local adjustments of the cell properties. The history-matched model showed that the top layers contained the attic oil owing to lack of perforations.
Lessons learned from this study include the idea that the material-balance work should precede any numerical flow-simulation study because it provides invaluable insights into reservoir-drive mechanisms and integrity of various input data, besides giving a rapid assessment of the reservoir's flow behavior. Credible material-balance work leaves very little room for adjustment of original hydrocarbons in place, which constitutes an excellent starting point for numerical models.
Improved Understanding of Reservoir Fluid Dynamics in the North Sea Snorre Field by Combining Tracers, 4D Seismic, and Production Data
Authors: Huseby O. , Andersen M. , Svorstøl I. , Dugstad Ø 
Published: March 2009

Summary
To obtain improved oil recovery (IOR), it is crucial to have a best-possible description of the reservoir and the reservoir dynamics. In addition to production data, information can be obtained from 4D seismic and from tracer monitoring. Interwell tracer testing (IWTT) has been established as a proven and efficient technology to obtain information on well-to-well communication, heterogeneities, and fluid dynamics. During such tests, chemical or radioactive tracers are used to label water or gas from specific wells. The tracers then are used to trace the fluids as they move through the reservoir together with the injection phase.
At first tracer breakthrough, IWTT yields immediate and unambiguous information on injector/producer communication. Nevertheless, IWTT is still underused in the petroleum industry, and data may not be used to their full capacity—most tracer data are used in a qualitative manner (Du and Guan 2005). To improve this situation, we combine tracer-data evaluation, 4D seismic, and available production data in an integrated process. The integration is demonstrated using data from the Snorre field in the North Sea. In addition to production data, extensive tracer data (dating back to 1993) and results from three seismic surveys acquired in 1983, 1997, and 2001 were considered.
Briefly this study shows that
Seismic and tracer data applied in combination can reduce the uncertainties in interpretations of the drainage patterns. Waterfronts interpreted independently by tracer response and seismic dimming compare well. Seismic brightening interpreted as gas accumulation is supported by the gas-tracer responses.
Fluid-Loss Control Improves Performance of Viscoelastic Surfactant Fluids
Authors: Huang Tianping , Crews James B. 
Published: March 2009

Summary
Viscoelastic surfactant (VES) fluids have been widely used as gravel-packing, frac-packing and fracturing fluids for more than a decade because the fluids exhibit excellent rheological properties and maintain low formation-damage characteristics compared with crosslinked-polymer fluids (Nehmer, 1988; Brown et al. 1996). Because of its non-wall-building property, VES fluid has much higher fluid leakoff into the reservoir matrix than wall-building polymer fluid. For frac-packing, this high-leakoff property has limited VES fluid's application to reservoirs with permeability of less than 400 md. Excessive fluid leakoff also significantly increases the cost of treatment.
This paper will introduce new technology for controlling the fluid loss of VES fluids to approximately 300°F. New fluid-loss control agents have been developed that, through chemisorption and surface-charge attraction, associate with VES micelles to produce a pseudo-filter-cake of viscous VES fluid that significantly reduces the rate of fluid loss. Use of this technology will reduce the VES fluid volume required for a given treatment by up to two-thirds and extends the permeability range of VES fluids to approximately 2000 md. The fluid-loss control agents are tiny particles that are used at relatively low concentrations. The tiny particles will be flowed back with the production fluid after VES micelles are broken by internal breakers. The rate of the pseudo-filter-cake cleanup is enhanced by use of internal VES breakers. The results of rheology, leak-off, and core flow tests will be presented for the VES fluid systems at temperatures 150°F and 250°F.