bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prudhoe Bay Well P2-15 Surface Casing Failure
Authors: Anders J. , Cismoski D. , Daniel R. , Dube A. , Engel H. , Hughes A. , Norene T. , Hamilton R. , Mohr W. 
Published: September 2008

Summary
While pre-heating the surface casing landing mandrel in preparation of welding to repair a leak on Prudhoe Bay well P2-15, the wellhead suddenly and unexpectedly moved downward approximately 18 inches. This failure resulted in an injury and required a rig workover to repair the well.
The wellhead was cut below the surface casing landing mandrel and sent to a company specializing in metallurgical analysis to determine the cause of movement. A section of the surface casing was identified with reduced wall thickness due to drilling wear. As heat was applied to raise the wellhead to welding temperature, the reduced wall thickness section of the surface casing experienced a temperature increase greater than the design pre-heat temperature. This thin-walled section of the casing began losing tensile strength, eventually resulting in the surface casing collapsing inward and allowing the wellhead to rapidly subside.
This paper discusses the causes of the failure and presents recommendations to prevent future failures of this type.
Thermodynamics of Compact Downhole Turbo Generators
Authors: Fernandez V. John , Ghosh Parthasarathi , James Darryl 
Published: September 2008

Abstract
A turbine assembly for downhole use is being developed for use in drill pipe and annular locations in the well that require small power generation devices. Such devices are required in high speed data transmission drilling strings currently being introduced in the industry. Discrete array of sensor banks mounted on the wired drill string require a local power source that directs electric energy to tools located in a particular sensored section of the well being drilled.
The thermodynamics of the compact generators is typically cyrocooling with reverse Brayton cycle expansion, liquefying in bulk gases such as helium. The high efficiency compared to membrane separation makes this method of helium distillation suitable for diverse uses such as NMR equipment and superconducting conductors.
This paper details the thermodynamics of a high-efficiency cycle power generation system for such drill strings the development of components in the system used to arrive at the target efficiency levels defined by the generation cycle. The lessons learnt from the cryogenic compact turboexpanders, which include mixed radial inlets and axial discharge configurations are illustrated in the development of this turbine generator for downhole drilling use. Additionally, supercomputer simulations on structural and fluid mechanics conditions downhole are used are used to understand, in detail, the system and component level thermodynamics of the turbo-generator.
The conclusions of this thermodynamic cycle development work is that a small profile, side-mounted power source can be development for use in drilling applications, particularly where the center bore of the drill string is required to be a clear pathway. The small profile of this solution enables completion strings used in intelligent fields to be powered, in addition, where the side-mounted power source is readily integrated into small cross-sections.
3D GIS as an Integrated Framework for Drilling Site Location Optimization
Authors: Ershaghi Milad A. 
Published: September 2008

Abstract
Given a table of 30,000 coordinate pairs representing the geographic locations of potential sites for new wells to be drilled and a repository of lease, platform, pipeline, directional survey, production, and chronostratigraphic data spanning the Gulf of Mexico region, we demonstrate how a 3D GIS can be used as an integrating technology to facilitate determination of the optimal well location.
Previous studies have highlighted the user interface, data management, 2D analytical, and surface visualization capabilities of GIS technology as it applies to E&P workflows, but have not addressed the same technology's programmatic customization, 3D analytical, and subsurface visualization capabilities. This is due in part to the fact that the range of features and capabilities found in tools that ship with the GIS product are adequate for most GIS users' needs, and the justification to explore the software's programmatic capabilities is frequently unmet. Furthermore, 3D technology is relatively new, tools supporting visualization and analysis based on 3D technology are in limited availability, and 3D has traditionally been regarded as a non-vital feature of information visualization rather than a dimension of data upon which analytical processes can be improved.
Through custom code written that programmatically exercises the GIS software's engine via an API, we demonstrate how vector geometry representations of features can be persisted into a geospatial database, 3D computational geometry interfaces can be used to derive new vector datasets from this data, geostatistical interpolation techniques can used to construct probability surfaces from these derivative datasets, and a set of optimal locations can be determined through an integrated analysis of this data. We discuss how the entire process can be automated to dynamically respond to changes in input data, the results of analyses can be visualized in 3D, and visual patterns found in data can be leveraged to correlate between fields on a regional scale and guide future exploration efforts.
This paper is significant in that it presents the 3D analytical capabilities of GIS software as it applies to E&P workflows, provides examples of customizations, and encourages exploration of 3D GIS as a technology for making better integrated decisions.
Multiple Mixing-Cell Method for MMP Calculations
Authors: Ahmadi Kaveh , Johns Russell T. 
Published: September 2008

Abstract
The minimum miscibility pressure (MMP) is a key parameter governing the displacement efficiency of gas floods. There are several methods to determine the MMP, but the most accurate methods are slim-tube experiments, analytical methods, and numerical simulation/cell-to-cell methods. Slim-tube experiments are important to perform because they use actual crude oil, but they are costly and time consuming. Analytical methods that use the method of characteristics (MOC) are very fast and help to understand the structure of gas floods. MOC, however, relies on finding the unique and correct set of key tie lines in the displacements, which can be difficult. Slim-tube simulation methods and their simplified cell-to-cell derivatives can be slow and their MMP estimates clouded by dispersion.
This paper presents a simple and accurate multiple mixing cell method for MMP calculations that corrects for dispersion, and is substantially faster than simulation methods. Unlike previous "mixing cell" methods, our cell-to-cell mixing model uses a variable number of cells, and is independent of gas-oil ratio, volume of the cells, excess oil volumes, and the amount of gas injected. The new method relies on robust P-T flash calculations using any cubic equation-of-state (EOS). The calculations begin with only two cells and perform additional cell-to-cell contacts between resulting equilibrium phase compositions based on equilibrium gas moving ahead of the equilibrium liquid phase. We show for a variety of oil and gas compositions that all key tie lines can be found to the desired accuracy, and that they are nearly identical to those found using analytical MOC methods. Our approach, however, is more accurate and robust than those from MOC because we do not make approximations regarding shocks along nontie-line paths, and the unique set of key tie lines converge automatically.
The MMP using our mixing cell method is estimated from four or five pressure calculations based on a power-law extrapolation of the smallest tie line to zero length. Our multiple mixing cell method can calculate either the MMP or the minimum miscibility for enrichment (MME) independent of the number of components in the gas or oil. Our approach further supports the notion that the MMP is independent of fractional flow since we obtain the same key tie lines independent of how much fluid is moved from one cell to another.
Diabetes, Abdominal Adiposity, and Atherogenic Dyslipoproteinemia in Women Compared With Men
Authors: Williams Ken , Tchernof Andre , Hunt Kelly J. , Wagenknecht Lynne E. , Haffner Steven M. , Sniderman Allan D. 
Published: September 2008

OBJECTIVE—To understand why atherogenic risk differs more between diabetic and nondiabetic women than between diabetic and nondiabetic men.
RESEARCH DESIGN AND METHODS AND RESULTS—Measures of cardiovascular risk, body composition, and serum hormones from the baseline examinations of the Insulin Resistance Atherosclerosis Study on 524 nondiabetic women, 258 diabetic women, 421 nondiabetic men, and 220 diabetic men were compared to detect greater adverse differences in women than in men. Systolic blood pressure; apolipoprotein B (apoB); total cholesterol; apoB–to–apoA-I ratio; non-HDL cholesterol; LDL particle count, small LDL, and intermediate-density lipoprotein by nuclear magnetic resonance; and C-reactive protein exhibited significant diabetes-sex interaction (P &lt; 0.05). ApoB exhibited the most significant interaction (P = 0.0005). Age- and ethnicity-adjusted apoB means were lower in nondiabetic women than nondiabetic men (102.4 vs. 106.8 mg/dl, P &lt; 0.05) but higher in diabetes (115.7 vs. 110.2 mg/dl, P &lt; 0.01). Plotted against BMI, waist circumference was 6% higher and hip circumference 10% lower in diabetic than nondiabetic women (both P &lt; 0.05), whereas the circumference measures did not differ conspicuously between diabetic and nondiabetic men.
CONCLUSIONS—In diabetic women, an elevated level of atherogenic particles, as manifested by apoB and LDL particle count, which may result from abdominal adiposity, represents a major treatable cardiovascular risk factor.
Virulence Potential of Staphylococcus aureus Strains Isolated From Diabetic Foot Ulcers
Authors: Sotto Albert , Lina Gérard , Richard Jean-Louis , Combescure Christophe , Bourg Gisèle , Vidal Laure , Jourdan Nathalie , Etienne Jérôme , Lavigne Jean-Philippe 
Published: September 2008

OBJECTIVE—The purpose of this study was to assess the virulence potential of Staphylococcus aureus strains isolated from diabetic foot ulcers and to discriminate noninfected from infected ulcers.
RESEARCH DESIGN AND METHODS—Diabetic patients hospitalized in a diabetic foot department with a foot ulcer were prospectively enrolled if they had been free of antibiotic treatment over the previous 6 months. At admission, ulcers were classified as infected or noninfected on the basis of clinical examination, according to the International Working Group on the Diabetic Foot system. Only patients carrying S. aureus as the sole pathogen were included. In individuals with a grade 1 ulcer, a second bacterial specimen was obtained 1 month later. Using virulence genotyping markers, clonality tools, and an in vivo Caenorhabditis elegans model, we correlated the virulence of 132 S. aureus strains with grade, time of collection, and ulcer outcome.
RESULTS—Among virulence genes, the most relevant combination derived from the logistic regression was the association of cap8, sea, sei, lukE, and hlgv (area under the curve 0.958). These markers were useful to distinguish noninfected (grade 1) from infected (grades 2–4) ulcers and to predict wound status at the follow-up. With use of the nematode model, S. aureus strains isolated from grade 1 ulcers were found to be significantly less virulent than strains from ulcers at or above grade 2 (P &lt; 0.001).
CONCLUSIONS—This study highlights the coexistence of two S. aureus populations on diabetic foot ulcers. A combination of five genes that may help distinguish colonized grade 1 from infected grade ≥2 wounds, predict ulcer outcome, and contribute to more appropriate use of antibiotics was discovered.
Sociodemographic Correlates of the Increasing Trend in Prevalence of Gestational Diabetes Mellitus in a Large Population of Women Between 1995 and 2005
Authors: Anna Vibeke , van der Ploeg Hidde P. , Cheung N. Wah , Huxley Rachel R. , Bauman Adrian E. 
Published: September 2008

OBJECTIVE—Gestational diabetes mellitus (GDM) is an increasingly prevalent risk factor for the development of type 2 diabetes in the mother and is responsible for morbidity in the child. To better identify women at risk of developing GDM we examined sociodemographic correlates and changes in the prevalence of GDM among all births between 1995 and 2005 in Australia's largest state.
RESEARCH DESIGN AND METHODS—A computerized database of all births (n = 956,738) between 1995 and 2005 in New South Wales, Australia, was used in a multivariate logistic regression that examined the association between sociodemographic characteristics and the occurrence of GDM.
RESULTS—Between 1995 and 2005, the prevalence of GDM increased by 45%, from 3.0 to 4.4%. Women born in South Asia had the highest adjusted odds ratio (OR) of any region (4.33 [95% CI 4.12–4.55]) relative to women born in Australia. Women living in the three lowest socioeconomic quartiles had higher adjusted ORs for GDM relative to women in the highest quartile (1.54 [1.50–1.59], 1.74 [1.69–1.8], and 1.65 [1.60–1.70] for decreasing socioeconomic status quartiles). Increasing age was strongly associated with GDM, with women aged &gt;40 years having an adjusted OR of 6.13 (95% CI 5.79–6.49) relative to women in their early 20s. Parity was associated with a small reduced risk. There was no association between smoking and GDM.
CONCLUSIONS—Maternal age, socioeconomic position, and ethnicity are important correlates of GDM. Future culturally specific interventions should target prevention of GDM in these high-risk groups.
Predicting 6-Year Mortality Risk in Patients With Type 2 Diabetes
Authors: Wells Brian J. , Jain Anil , Arrigain Susana , Yu Changhong , Rosenkrans Wayne A. , Kattan Michael W. 
Published: September 2008

OBJECTIVE—The objective of this study was to create a tool that predicts the risk of mortality in patients with type 2 diabetes.RESEARCH DESIGN AND METHODS—This study was based on a cohort of 33,067 patients with type 2 diabetes identified in the Cleveland Clinic electronic health record (EHR) who were initially prescribed a single oral hypoglycemic agent between 1998 and 2006. Mortality was determined in the EHR and the Social Security Death Index. A Cox proportional hazards regression model was created using medication class and 20 other predictor variables chosen for their association with mortality. A prediction tool was created using the Cox model coefficients. The tool was internally validated using repeated, random subsets of the cohort, which were not used to create the prediction model.RESULTS—Follow-up in the cohort ranged from 1 day to 8.2 years (median 28.6 months), and 3,661 deaths were observed. The prediction tool had a concordance index (i.e., c statistic) of 0.752.CONCLUSIONS—We successfully created a tool that accurately predicts mortality risk in patients with type 2 diabetes. The incorporation of medications into mortality predictions in patients with type 2 diabetes should improve treatment decisions.
Additive Interaction of Hyperglycemia and Albuminuria on Risk of Ischemic Stroke in Type 2 Diabetes
Authors: Yang Xilin , Ko Gary T.C. , So Wing Yee , Ma Ronald C.W. , Kong Alice P.S. , Lam Christopher W.K. , Ho Chung Shun , Chow Chun-Chung , Tong Peter C.Y. , Chan Juliana C.N. 
Published: September 2008

OBJECTIVE—The study aims to test whether biological interaction between hyperglycemia and albuminuria can explain the inconsistent findings from epidemiological studies and clinical trials about effects of hyperglycemia on stroke in type 2 diabetes.
RESEARCH DESIGN AND METHODS—A total of 6,445 Hong Kong Chinese patients with type 2 diabetes and free of stroke at enrollment were followed up for a median of 5.37 years. Spline Cox proportional hazard regression was used to obtain hazard ratio curves, which were used to identify cutoff points of A1C and spot urinary albumin–to–creatinine ratio for increased ischemic stroke risk. The identified cutoff point of A1C was used to check biological interaction between A1C and albuminuria (micro- and macroalbuminuria). The biological interaction was estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index.
RESULTS—During the follow-up period, 4.45% (n = 287) of patients developed ischemic stroke. A1C was associated with increased hazard ratios of ischemic stroke in a near-linear manner except for two points—6.2 and 8.0%—where the slope between these two points accelerated. For A1C values &lt;6.2%, the presence of micro/macroalbuminuria did not confer additional risk, while significant biological interaction between A1C and micro/macroalbuminuria for values ≥6.2% was observed (RERI 0.92, 95% CI 0.16–1.68, and AP 0.40, 0.01–0.78).
CONCLUSIONS—A1C ≥6.2% and micro/macroalbuminuria interact to markedly increase the ischemic stroke risk, which explains a large proportion of risk in patients with type 2 diabetes harboring both risk factors.
Plasma Adiponectin Does Not Correlate With Insulin Resistance and Cardiometabolic Variables in Nondiabetic Asian Indian Teenagers
Authors: Snehalatha Chamukuttan , Yamuna Annasami , Ramachandran Ambady 
Published: September 2008

OBJECTIVE—The objectives of this study were to determine age- and sex-specific concentrations of adiponectin in Asian Indian teenagers and adults and to assess whether its blood levels correlated with insulin resistance and other cardiometabolic parameters.
RESEARCH DESIGN AND METHODS—We studied 196 teenagers (94 boys, 102 girls) 12–18 years of age, selected from a cohort of 2,640 individuals from a cross-sectional school-based survey in Chennai, India. For comparison, adiponectin and plasma insulin were measured in 84 healthy adults. Correlation of adiponectin with plasma levels of insulin, proinsulin, insulin resistance, anthropometry, and family history of diabetes were studied.
RESULTS—Adiponectin showed a sex dimorphism, with girls having higher values (in μg/ml) (10.3 ± 5.0) than boys (8.4 ± 3.5) (P &lt; 0.0001), and it showed a positive correlation with HDL cholesterol in boys only and not with other lipid parameters, insulin resistance, proinsulin, anthropometry, and family history of diabetes. In the adults, adiponectin correlated with fasting glucose and inversely with triglycerides.
CONCLUSIONS—In Asian Indian adults and teenagers, adiponectin did not correlate directly with measures of insulin sensitivity, overweight, and other cardiometabolic variables. This was at variance with several reports in other populations showing an inverse association of adiponectin with insulin resistance, proinsulin, and BMI, suggesting ethnic differences in the relationship of adiponectin with insulin sensitivity. The role of adiponectin in relation to action of insulin needs more detailed studies in Asian Indians.
High Blood Pressure Before and During Early Pregnancy Is Associated With an Increased Risk of Gestational Diabetes Mellitus
Authors: Hedderson Monique M. , Ferrara Assiamira 
Published: September 2008

OBJECTIVE—While women with prior gestational diabetes mellitus (GDM) are more likely to display features of the metabolic syndrome, including hypertension, in the years after delivery, it is unclear whether these components are also present before pregnancy. We examined the relationship between blood pressure (BP) measured before and during early pregnancy (&lt;20 weeks) and the risk of GDM in a nested case-control study.
RESEARCH DESIGN AND METHODS—Case (n = 381) and control (n = 942) subjects were selected from a cohort of women delivering between 1996 and 1998 and screened for GDM between 24 and 28 weeks’ gestation. GDM was defined by the National Diabetes Data Group criteria. BP and covariates data were obtained by review of the medical records. Women were categorized according to BP levels recommended by the American Heart Association outside of pregnancy: &lt;120/80 mmHg (normal), 120–139/80–89 mmHg (prehypertension), and ≥140 and/or ≥90 mmHg or use of antihypertensive medications (hypertension).
RESULTS—During early pregnancy, women with prehypertension had a small increased risk of GDM (odds ratio [OR] 1.56 [95% CI 1.16–2.10]), and women with hypertension had a twofold increased risk of GDM (2.04 [1.14–3.65]) compared with women with normal BP after adjusting for age, race/ethnicity, gestational week of BP, BMI, and parity. Similar results were seen among the subset of women with BP levels measured before pregnancy (1.44 [0.95–2.19] for prehypertension and 2.01 [1.01–3.99] for hypertension).
CONCLUSIONS—Clinicians should be aware that women presenting with hypertension may warrant early screening or intervention to prevent GDM.
Cognitively impaired older adults exhibit comparable difficulties on naturalistic and laboratory prospective memory tasks
Authors: Will Christine M. , Rendell Peter G. , Ozgis Sesil , Pierson Jane M. , Ong Ben , Henry Julie D. 
Published: September 2008

AbstractProspective memory, or remembering future intentions, is critical for independent living for all ages, but especially older adults. Previous laboratory research has found that cognitively impaired older adults may have particular difficulties with prospective memory, but previous studies have not examined whether these difficulties occur in everyday life. In normal ageing, a dissociation between settings has been observed, with older adults selectively impaired in laboratory (but not naturalistic) contexts. Consequently, in the present study 15 cognitively impaired older adults were compared to demographically matched controls on laboratory and naturalistic measures of prospective memory. The results indicated that the cognitively impaired group performed more poorly on both measures, with the magnitude of the deficit comparable across setting. These results indicate that for older adults who present with cognitive impairment prospective memory deficits observed in laboratory settings may be a valid indicator of difficulties experienced executing delayed intentions in everyday life. Copyright © 2008 John Wiley & Sons, Ltd.