bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implementing the national invasive cervical cancer audit: correlation between local and regional classification
Authors: Moss E L , Askew S , Jones P W , Redman C W E , Pearmain P 
Published: January 2011

Objective To determine the accuracy of information recorded regionally and locally on the screening classification of cervical cancer cases using the national invasive cervical cancer audit categories. Methods Comparison of the audit categorization of all cervical cancer cases diagnosed at the University Hospital of North Staffordshire (UHNS) between January 2003 and December 2006 with the classification assigned by the West Midlands Cervical Screening Quality Assurance Reference Centre (WMQARC). Results Eighty-seven cases of cervical cancer were diagnosed during the three-year study period. There was agreement between the UHNS and WMQARC classification of cases in 52 cases (59.7%), moderate agreement κ = 0.51 (95% CI 0.39–0.63). The greatest disparity was seen in the classification of lapsed attenders, with nine of the 26 cases categorized as ‘lapsed’ by the UHNS being assigned to the ‘lost to follow-up’ category by WMQARC. Three cases were deemed unclassifiable by WMQARC using the national classification since the women were over the age of 70 years but had previously been enrolled in the screening programme, and currently there is no national category for these women. Conclusions Accurate and consistent classification of invasive cervical cancer cases is essential in order to obtain useful information on the efficiency of the national screening programme at a local, regional and national level. The use of a national algorithm would provide reassurance that all data used in the national evaluation of the NHS Cervical Screening Programme are consistent, meaning that robust conclusions could then be drawn from the data.
Women's preferences for the delivery of the National Health Service Breast Screening Programme: a cross-sectional survey
Authors: Linsell Louise , Forbes Lindsay J L , Patnick Julietta , Wardle Jane , Austoker Joan , Ramirez Amanda J 
Published: January 2011

Objective To elicit women's preferences for delivery of the National Health Service (NHS) Breast Screening Programme. Design Interview survey. Setting Private households in the UK. Population Five hundred and ninety-seven women aged 45–75 interviewed as part of the National Statistics Omnibus Survey, December 2008 and January 2009. Outcomes Preferred setting (hospital or community) and preferred type of screening unit (mobile or permanent). Rated importance of distance, time, convenience and cost of travelling to a screening unit. Results Forty per cent of women did not mind whether the screening unit was based in a community or hospital setting, and 52% did not mind whether the unit was permanent or mobile. Among those who expressed a preference, 59% preferred a hospital to a community setting, and 62% preferred a permanent to a mobile unit. Many women (63%) said distance to a breast screening unit was an important factor, as was time to travel (58%). Among those with access to a car, 80% regarded the availability of parking as important, but only 40% regarded the cost of car travel as important. Among women with no access to a car, there was a similar pattern for ease of public transport (76%) and cost of public transport (48%). Conclusions Many women were unconcerned about the type and setting of breast screening units. Among those who were concerned, most preferred hospital over community settings and permanent over mobile units, but nonetheless most women said time and distance were important. Well-situated units with advanced publicity about public transport links and parking facilities may encourage greater uptake.
A randomized double-blind crossover trial to investigate the efficacy of screening for adult hypothyroidism
Authors: Abu-Helalah M , Law M R , Bestwick J P , Monson J P , Wald N J 
Published: January 2011

Objective To assess the value of population screening for adult hypothyroidism. Setting Healthy people attending for a general health assessment. Methods A thyroid-stimulating hormone (TSH) measurement was performed on people attending for a general health assessment (women aged 50–79 [35–49 with a family history of thyroid disease] and men aged 65–79). Those with TSH levels above 4.0 mU/L were invited to join a randomized double-blind crossover trial of thyroxine and placebo, each given in random order for four months. On entry a second blood sample was collected for a TSH measurement after the end of the trial to determine whether this would help select individuals for thyroxine treatment. The daily thyroxine dose started at 50 µg and if necessary was increased to achieve a TSH level of 0.6–2.0 mU/L. Results There were 341 (8%) people with a TSH level above 4.0 mU/L, 110 met eligibility criteria (64 agreed to participate), and 56 (49 women, 7 men) completed the trial. Among the 15 individuals with a repeat TSH measurement above 4.5 mU/L, 11 reported feeling better on thyroxine than placebo and none reported feeling better on placebo ( P = 0.001; four felt no different), indicating that in this group 73% benefitted (i.e. 11/15; 95% CI 45–92%). The main symptoms relieved were tiredness and loss of memory. There was no indication of harm. In the 41 individuals with a repeat serum TSH of 4.5 mU/L or less: 10 reported feeling better on thyroxine than placebo and 16 better on placebo ( P = 0.42, 15 felt no different). Thus about 8% of men and women in the specified age groups had a TSH above 4.0 mU/L, and of these about a quarter had a repeat TSH above 4.5 mU/L, of whom about half would benefit from thyroxine treatment. Conclusion The results indicate that screening for hypothyroidism would be worthwhile. Approximately 1% of people screened would have a better quality of life. Pilot screening programmes for adult hypothyroidism are justified.
Laboratory Tests of Window-Wall Interface Details to Evaluate the Risk of Condensation on Windows
Authors: Maref Wahid , Van De Bossche Nathan , Armstrong Marianne , Lacasse Michael A. , Elmahdy Hakim , Glazer Rock 
Published: January 2011

Abstract
The development of alternative details to manage water intrusion at the window-wall interface has produced a number of novel approaches to detailing the interface between the window and the adjacent wall assembly. Many of these approaches advocate the need to provide drainage at the rough opening of the window subsill, given that the window components themselves are susceptible to water entry over their expected life. Depending on the types of windows used and the cladding into which the windows are installed, there arise different methods to provide drainage that may also affect air leakage through the assembly. This in turn may give rise to the formation of condensation along the window, at the sill, or along the window sash and glazing panels. Hence, there is a need to determine if, under cold weather conditions, specific interface details that incorporate sill pans provide a potential for condensation on the window components in which air leakage paths may be prominent at the sill or elsewhere on the window assembly. The paper reports on a laboratory evaluation of conditions suitable for the formation of condensation at the window frame perimeter of the interface assembly as a function of both temperature deferential and air leakage rate across the test assembly. A summary of the laboratory test protocol is provided, which includes a description of the test setup and apparatus, fabrication details of the specimen, information on instrumentation and calibration, and experimental results for one type of window (flange window). In parallel, preliminary simulation results were presented and compared to those obtained from the experiment using the commercially available thermal software BISCO.
Spatial Distribution of the Compressive Stress-Strain of Recycled Polymeric Piling
Authors: Iskander Magued G. , Bozorg-Haddad Amir H. 
Published: January 2011

Abstract
Fiber reinforced polymer (FRP) composites represent an alternative construction material without many of the performance disadvantages of traditional construction materials. The use of FRP as a pile material can eliminate deterioration problems of conventional piling materials in water front environments and aggressive soils. Most of the available polymeric piling for light load applications is made of foamed recycled High Density Polyethylene (HDPE). A comprehensive understanding of the mechanical properties of foamed recycled polymers is essential for widespread use of polymeric piling. This paper presents the results of 178 compression tests conducted to assess the in-plane spatial distribution of the compressive strength of piling made of foamed recycled HDPE. Several methods were attempted to predict the stress-strain of the cross section from the compressive strength of small coupons extracted from within the cross section. Comparing the predicted behavior from coupon specimens to the measured behavior obtained by loading the whole cross section illustrates that the approach is promising.
A Nondamaging Friction Reducer for Slickwater Frac Applications
Authors: Sun Hong , Wood Benjamin , Stevens Dick , Cutler Jennifer , Qu Qi , Lu Meng 
Published: January 2011

Abstract
Friction reducers used in slickwater fracturing can cause damage to the formation and, especially, to natural fractures because of their chemical nature as high molecular weight polyacrylamides and because of the large volumes injected during a typical treatment. Such concerns can be addressed with two approaches: 1. developing more effective friction reducers with a) more efficient polymers and/or b) faster hydration to shorten the dormant period before friction reducers are fully hydrated, considering the fact that fluids typically travel from surface to perforation within only 3 minutes; 2. developing breakable friction reducers, which are effective during pumping but degrade under downhole conditions, leaving little residue.
A new friction reducer was developed, encompassing all of these desired features. Improved hydration and more effective chemistry make it possible to achieve significant reduction of polymer loading in the field, and effective breaking downhole minimizes residue. The new friction reducer is delivered in liquid form to simplify logistics and field operations. It is very effective as a friction reducer, compatible with common chemical additives (scale inhibitors, biocides, clay stabilizers, surfactants, brines, etc) and stable under mechanical shearing. More than 30 multi-stage slickwater frac completions have been performed using this new friction reducer in tight sandstone and shale formations. The effectiveness of the friction reducer was compared with conventional ones during the field trials and will be described in the paper. The field results were corroborated by laboratory tests of the new friction reducer in water and various brines. This paper will also present chemical compatibility, breaking profiles and formation damage studies on tight sandstone and shale formation core in comparison with conventional products. Production history of field-trial wells for 30, 60, 90 days will be presented and compared to those of the offsets.
Multiple-Fractures Propagation, Orientation and Complexities in Drilling Waste Injection
Authors: Shokanov T. , Gumarov S. , Ronderos J. , Fragachán F. E. 
Published: January 2011

Abstract
The subsurface injection of drilling waste has become an increasingly popular and well-accepted technology over the last several decades. The popularity of this technology is primary spurred by its economic advantages in meeting more stringent drilling waste management requirements, especially in remote and environmentally sensitive areas. Furthermore, its use has become more attractive with the dramatic development and improvement in the processes associated with surface and sub-surface engineering, fracture modeling, risks identification and mitigation options, injection monitoring and in-depth pressure analysis. Together, these advancements have improved considerably the assurance and efficiency of waste injection operations worldwide.
Nevertheless, despite the tremendous advancements in the fracture modeling attained from subsurface feasibility studies, a major uncertainty exists with the propagation of multiple-fractures that apparently accompanies the intermittent batch injection process, essential to the drilling waste injection operation. The propagation of multiple-fractures, along with their orientation and complexities, strongly influence the fracture design, ultimate disposal capacity and injection pressure behavior. Consequently, this uncertainty is a critical issue, both in drilling waste injection and re-fracturing in conventional stimulation treatments.
This paper describes the evolution of understanding of multiple-fracture mechanics in drilling waste injection, starting from the conventional "wagon-wheel" uniform disposal-domain concept to the branching multiple-fractures approach that becomes practical through mathematical computations of near-wellbore changes in the stresses resulting from prior fracture creation and solids accumulation. Moreover, the authors present four potential scenarios of subsequent fracture initiation and propagation during intermittent injections, and provide revised re-assessment of data from the joint industry Mounds Drill Cuttings Injection Field Experiment.
Rheology Measurements of Concentrated Broken Gel for Filtercake Modeling
Authors: Gdanski Rick , Bryant Jason 
Published: January 2011

Abstract
A common explanation for disappointing production results from fracturing treatments in tight-gas sand reservoirs is gel filtercake damage. Gel filtercake rheology is poorly understood, which makes modeling efforts difficult. The current method of describing gel filtercake movement is by measuring the "pressure drop to initiate flow" in special laboratory tests conducted at room temperature and atmospheric pressure. Typical filtercake concentrations are considered to be 0.6 to 0.8 lbm/gal, but can become much higher on fracture closure in low sand-concentration proppant packs. Laboratory experiments have been completed that measured the rheology of concentrated depolymerized (broken) hydroxypropyl guar (HPG) across a molecular weight (MW) range of 26 to 580 Kg/mole, a temperature range of 60 to 280°F, a concentration range of 0.25 to 3 lbm/gal, and shear rates of 0.001 to 1000 1/sec. Results from these experiments have been applied to calculate apparent pressure drops to initiate flow of decrosslinked filtercakes across a broad range of conditions.
The rheology of the noncrosslinked fluids was found to have Carreau type behavior. The Flory-Huggins equation was used to match the behavior of the infinite and zero shear rate viscosities at a reference temperature of 62°F. The remaining Carreau parameters were determined as a function of temperature and MW. The complete rheology model is presented. The rheology model was combined with flow-through porous media equations to successfully determine apparent pressure drops to initiate flow according to the currently accepted experimental criteria. This work significantly advances the understanding of the rheology of decrosslinked filtercakes, demonstrates that the Carreau behavior can still exhibit an apparent pressure drop to initiate flow in porous media, and provides a useful rheology model for further fracture-cleanup modeling.
New Thermo Thickening Associative Polymer System Pushes Limits of Surfactant Gels
Authors: Shaefer M. , Carman P. S. , Ngoma V. 
Published: January 2011

Abstract
When viscoelastic fluids systems first appeared, they provided a very good non-damaging no polymer option for many tight gas applications. These fluids were operationally simplistic with only a few additives, usually less than five. However, they are temperature limited to about 140°F as a single fluid. For temperatures to about 220°F you have to foam with gas (carbon dioxide (CO2) or nitrogen (N2), usually 65 to 75 quality (Q) in order to achieve stability with adequate viscosity. In addition the typical VES systems do not have very good friction reduction because at high shear they tend to behave more like water.
The new thermo thickening system raises the temperature limit for traditional VES fluids. Rheology testing exhibits good structure along with viscosity. The time necessary to gel with temperature can be accelerated and delayed chemically. Although it does contain a polymer, regain conductivity tests show very high numbers usually associated with VES fluids. The system also exhibits unique traits of clay control, surfactant properties and fluid loss. The system also has the potential to extend further as a foamed fluid. This project will show laboratory testing results and a field test case history of this new and unique fluid system.
Surface Area vs Conductivity Type Fracture Treatments in Shale Reservoirs
Authors: Ramurthy Muthukumarappan , Barree Robert D. , Kundert Donald P. , Petre Erik , Mullen Mike 
Published: January 2011

Abstract
Hydraulic fracturing continues to be the primary mechanism to produce hydrocarbons out of the tight shale reservoirs. Ever since the success of Barnett shale program, operators are inclined to pump similar large volume water fracture treatments with little or no proppants in their respective shale plays. This assumes that all shale plays are the same and react accordingly to large volume treatments. The basic objective behind such treatments is to contact large surface area, which has been very successful in the Barnett shale play. Such large volume treatments in other shale plays may not be an optimized solution for the specific shale attributes and the response may lead to uneconomical production results. Some shales based on their reservoir characteristics might require a conductivity type fracture treatment. So, it is important to understand the characteristics of these shales before deciding the stimulation treatments. In addition to core and log analysis of these shales, fluid sensitivity tests, Brinell hardness tests, unpropped fracture conductivity tests and more importantly a Diagnostic Fracture Injection Test (DFIT) can help define the guidelines for choosing between a surface area and a conductivity type fracture treatment.
Integrating the various data sources is important in arriving at these guidelines. The main objective of this paper is to provide these guidelines along with examples such that the costly trial and error approach for stimulating shales can avoided. Examples from both oil and gas shales namely, the Gothic, Haynesville, Eagle Ford and Barnett shale plays in the USA are included in this work.
Integrating Microseismic Mapping and Complex Fracture Modeling to Characterize Fracture Complexity
Authors: Cipolla C. , Weng X. , Mack M. , Ganguly U. , Gu H. , Kresse O. , Cohen C. 
Published: January 2011

Abstract
Microseismic mapping (MSM) has shown that the occurrence of complex fracture growth is much more common than initially anticipated and is becoming more prevalent with the increased development of unconventional reservoirs (shale-gas). The nature and degree of fracture complexity must be clearly understood to select the best stimulation design and completion strategy. Although MSM has provided significant insights into hydraulic fracture complexity, in many cases the interpretation of fracture growth has been limited due to the absence of evaluative and predictive hydraulic fracture models.
Recent developments in the area of complex hydraulic fracture propagation models now provide a means to better characterize fracture complexity. This paper illustrates the application of two complex fracture modeling techniques in conjunction with microseismic mapping to characterize fracture complexity and evaluate completion performance. The first complex fracture modeling technique is a simple, yet powerful, semi-analytical model that allows very efficient estimates of fracture complexity and distance between orthogonal fractures. The second technique is a gridded numerical model that allows complex geologic descriptions and more rigorous evaluation of complex fracture propagation.
With recent advances in complex fracture modeling, we can now evaluate how fracture complexity is impacted by changes in fracture treatment design in each geologic environment. However, quantifying the impact of changes in fracture design using complex fracture models alone is difficult due to the inherent uncertainties in both the Earth Model and "real" fracture growth. The integration of MS mapping and complex fracture modeling enhances the interpretation of the MS measurements, while also calibrating the complex fracture model. Examples are presented that show that the degree of fracture complexity can vary significantly depending on geologic conditions.
Fracture Stimulation Treatment Best Practices in the Bakken Oil Shale
Authors: Hlidek Barry T. , Rieb Brad 
Published: January 2011

Abstract
This paper summarizes fracture stimulation treatment best practices determined by a three-year study of production results of several thousand fracture treatments in more than 460 wells in the Bakken Shale formation in Saskatchewan, Canada. Treatment variables include: proppant type, proppant concentration, fracturing fluid formulation, treatment size, well-bore azimuth, and lateral frac density. Treatment effectiveness is based on four month cumulative production comparisons that include: oil, water, and total fluid.
The Bakken is a low-permeability oil and water-producing formation at a depth of about 1500 m (4900 ft). The study area covers about 390,000 hectares (1500 mile2) in the northern region of the Williston Basin. Wells in this region require propped fracture stimulations for economic production. All wells in this study are drilled horizontally, normally completed open-hole in the Middle Bakken. Most completions consist of isolated multistage treatments. One of the significant challenges encountered during fracture treatment design is the presence of an overlaying water aquifer, known as the Lodgepole. Fracture treatments that breach the Lodgepole aquifer are considered less than optimum because of excess water production.
This paper will also review design and operational considerations for the area, including treatment volumes, pump rates and fluid chemistry. Wells in the study were primarily completed with two types of water based fluids. Treatment size and treatment rates are important considerations. The requirement to limit fracture growth conflicts with the theoretical need for a large, conductive propped fracture. However, the study shows that proppant concentration and the resulting fracture conductivity impact fluid production. Lateral length, number of frac stages, and distance between stages are also addressed in the paper.
Results of this study will be presented as best practices that may be used to refine completion techniques to maximize hydrocarbon production without excessive water production in this important oil-producing basin.