bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Analysis of CO2-Sequestration Efficiency During Oil Recovery in Naturally Fractured Reservoirs
Authors: Trivedi J. J. , Babadagli T.
Published: October 2008

With urgent need of greenhouse gas sequestration and booming oil prices, underground oil/gas reservoirs seems the only value added choice. A great portion of current CO2 injection projects in the world is in naturally fractured reservoir. The matrix part of these reservoirs constitutes the major oil storage unit and this oil is targeted during CO2 injection. It is our intention to show that this media could also be used as permanent CO2 storage unit while recovering oil in it. These reservoirs, however, are complex in nature and the physics of the matrix-fracture interaction process during CO2 injection is still not known to great extend.

To ease the complex nature of the problems, experiments were performed on artificially fractured (single) Berea sandstone cores saturated with n-decane. CO2 was injected at constant rates into the fracture while maintaining the high pressure into the core and the system. Injection and production data were monitored and collected using continuous data logging system. After continuous injection diffusion of CO2 was allowed to occur by shutting down the system for a specific period of time and then following a blowdown period to produce oil recovered by diffusion from matrix to fracture. At different pressure steps, produced liquid was analyzed using gas chromatography while the produced gas measured using continuous flow meter. The CO2 storage capacity of the rock with change in the pressure and the amount of oil recovered during blow down period was analyzed.

The results of the continuous injection experiments were used to obtain diffusion coefficients by matching the simulation results. Using dimensionless analysis and matrix-fracture diffusion groups, a critical number for optimal recovery/sequestration was obtained. The pressure decay behavior during the shutdown was analyzed in conjunction with the gas chromatograph analysis of produced oil sample collected during blowdown after the quasi-equilibrium reached during pressure decay. This led to insights into the governing mechanism of extraction/condensation and miscibility for recovering lighter to heavier hydrocarbons during pressure depletion from fractured reservoirs.
Performance Gains Realized With PDC Bits in Air/Foam Applications in the Appalachian Basin
Authors: Lays R. E. , Grayson E.
Published: October 2008

PDC bits have afforded drillers a means to improve penetration rates in many applications. However, previous attempts to apply PDC technology in air/foam drilling environments have proven unsuccessful primarily due to excessively rapid cutter wear.

A successful test of modern PDC bit designs has been conducted in a foam drilling application of the Appalachian Basin, a widely drilled basin with well-known geological properties. The initiative included identifying applications and refining operating practices while measuring the economic viability of PDC bits in this environment. Encompassing a period of 24 months, this initiative has accumulated performance data from dozens of bit runs, with drilling cost savings and reduction/elimination of borehole deviation as its objectives.

The principle area of focus involves Ordovician period formations in eastern Ohio. Foam is the primary drilling medium with an occasional need to finish the section using light mud for well control. PDC performance has delivered an ROP increase of 300% and a 30% reduction of days-on-well. This proves the ability to reduce drilling costs with PDC bits in certain air and foam applications.

This paper details methods, results, and lessons learned from this study, and translates findings into practical techniques. Operating aspects are discussed, as well as formation characteristics and down-hole conditions. A case study is provided, including performance data and dull bit photographs.
Identifying, Bypassing, and Avoiding Gas Traps in Horizontal Wells
Authors: Kreh K. A.
Published: October 2008

When dealing with horizontal wells in gas reservoirs with low bottomhole pressure, it is important to avoid traps –– that is, S-shaped portions of the wellbore. These wellbore traps look and act similarly to the traps under a sink or toilet, which hold water in the dip to prevent low-pressure, odorous gases in the sewer from rising into a house.

When analyzing survey data from a horizontal well, it is sometimes difficult to identify traps just by looking at the numbers. There are a few different techniques that can be employed to solve this problem. One technique is to import the survey data into a spreadsheet and solve for the slope of the well. Once the slope is found, the traps can be determined from multiple changes of slope orientation in row. Another, more visually friendly method of identifying traps is the use of 3-D graphs. By importing the survey data into a 3-D graph, the traps can easily be identified by the "S" shaped curves in the wellbore.

Once located, traps can be bypassed; depending on the length and severity of the trap, a line can be run through the trap to provide an exit for the trapped gas. Periodic treatments of N2 can be used to blow trapped water out of traps, allowing gas to migrate to surface.

This paper will discuss the concept of traps in horizontal gas wells and different methods of identifying traps, including spreadsheets and 3-D graphs. The paper will conclude with useful means of bypassing existing traps and preventing traps in future horizontal drilling.
PRISE: Petroleum Resource Investigation Summary and Evaluation
Authors: Old S. , Holditch S. A. , Ayers W. B. , McVay D. A.
Published: October 2008

As conventional gas resources are depleted, unconventional gas (UG) resources (gas from tight sands, coal beds, and shale) are becoming increasingly important to U.S. and world energy supply. The volume of UG resources is generally unknown in most basins outside North America. However, in 25 mature North American basins, UG resources have been produced for decades, and resources and reserves are well characterized. The objective of this work was to evaluate recoverable UG resources and determine the quantitative relations between known conventional and unconventional hydrocarbon resources in mature North American basins, with the goal of using these relations to estimate unconventional hydrocarbon resources in basin outside North America, which we call frontier basins.

We used data from the U.S. Geological Survey, Potential Gas Committee, Energy Information Administration, National Petroleum Council, and Gas Technology Institute to evaluate relations among hydrocarbon resource types in the Appalachian, Black Warrior, Greater Green River, Illinois, San Juan, Uinta-Piceance, and Wind River basins. We chose these seven basins for preliminary analysis of relations between conventional and unconventional gas resources because they are mature basins for both conventional and unconventional oil and gas production. To conduct this analysis, we wrote a computer program that we call PRISE (Petroleum Resources Investigation Summary and Evaluation). Input data for PRISE, obtained from the published data sources, were the values of technically recoverable resources, which were the sum of the following resource categories: cumulative production, proved reserves, growth, and undiscovered recoverable resources. We then compared technically recoverable conventional and unconventional resources for each basin to evaluate relationship between conventional and unconventional resource volumes in these seven basins.

For the seven basins studied, we found that 10% of the total recoverable hydrocarbon resources are conventional oil and gas, whereas 90% of the recoverable hydrocarbons are unconventional resources. We propose that the results of this study may be used to estimate recoverable resources from unconventional gas reservoirs in target (frontier) basins, where conventional oil and gas resources are known but unconventional resources have not been evaluated.
Application of the Bergman-Sutton Method for Determining Blend Viscosity
Authors: Sutton R. P. , Bergman D. F.
Published: October 2008

As the petroleum industry accesses more low gravity oil resources, modification of viscosity by blending lighter hydrocarbons has become a necessity in order to attain bulk properties that will flow though a pipeline. In the more conventional oil reservoirs, the need to estimate the viscosity of oil blends occurs when reservoir fluids are contaminated with oil base muds or when production streams from different reservoirs or fields are commingled in a single pipeline. Several methods have appeared in the literature for estimating blend viscosity. All of these methods require a measured viscosity for each component of the blend. The number of viscosity measurements is compounded when the viscosity of the blended mixture is required at several temperatures. The Bergman and Sutton method has the widest range of temperature and oil API gravity of the viscosity correlations published and has been consistently demonstrated to provide accurate results over these conditions. This method requires the component specific gravity, characterization factor (Watson K) and temperature to estimate viscosity. By using the proper mixing rules, an estimate of blend viscosity can be made with comparable or improved accuracy over the "best" published methods without the need for individual component viscosity measurements. A database of 2000 blend viscosity measurements from over 800 mixtures was created to compare the accuracy of the various methods. Viscosity measurements of the individual components in the blends studied exceeded 7600 datapoints. A diverse group of mixtures ranging from light alkane or aromatic pure components to bitumen, diesel, biodiesel, condensate, crude and assay fractions were included in this database. Blends were comprised of the typical binary mixtures but ranged up to a maximum of eight components in the mixture.
Interference Testing Using Finite-Conductivity Horizontal Wells of Unequal Lengths
Authors: Awotunde A. A. , Al-Hashim H. S. , Al-Khamis M. N. , Al-Yousef H. Y.
Published: October 2008

This paper presents a model for interference testing utilizing two horizontal wells of unequal lengths. The model presented is a semi-analytical model solution for interference testing utilizing two finite-conductivity horizontal wells having unequal lengths.

This model extends the previous interference testing model between two equal-length horizontal wells to a more general case in which the two horizontal interfering wells are of unequal lengths.

Sensitivity studies are performed to show the effect of horizontal well length on (1) Flux distribution in the active and observation wells, and (2) Pressure response in the active and observation wells.
Logistics of Marcellus Shale Stimulation: Changing the Face of Completions in Appalachia
Authors: Perkins C. K.
Published: October 2008

The Appalachian Basin has long been known for its relatively shallow and associatively economical wells. However, in the fairly recent past the Marcellus Shale has caused a buzz in the industry reaching from the small independents of West Virginia to the established majors of Texas and beyond. This creates a two-fold problem for those parties interested in exploring this play. Firstly, how can the independents justify breaking into a tier of spending not typical of Appalachian Basin operations, and secondly, how can the majors create economical situations in an unfamiliar and challenging environment.

Although uniquely different, the path to each solution is similar, both attempting to create an economical and successful project. This begins with careful planning, and a realistic approach. For those familiar with the terrain and environmental challenges, a focus upon fiscal planning and careful economic research is necessary to walk the fine line between feasibility and cutting yourself short. Others may be familiar to large-scale projects, but inexperienced in the challenge that is Appalachia terrain.

All of this plays a direct impact on what may arguably be the most crucial aspect of the entire project – the stimulation design. Without proper planning and execution of site and approach construction, the majority of designs are moot. The facts are that Marcellus Shale wells demand large volumes of materials, delivered at a high rate.

This paper will explore the logistic challenges that any operator could expect to encounter in the Marcellus Shale, and will discuss stimulation design options shown by field experience in over 150 stimulations.
Investigation of Mud-Filtrate Invasion Using Computational Fluid Dynamics
Authors: Won S. , Bilgesu H. I. , Ameri S.
Published: October 2008

In spite of continued improvements in logging technology, mud-filtrate invasion and related formation damage due to drilling fluids can result in the misinterpreted values of rock and fluid properties in the reservoir. Well planning with accurate information of target reservoir would not only optimize drilling operation and completion but also maximizes production of oil and gas.

To produce hydrocarbons effectively, the wellbore must communicate with formations beyond the altered zone and this can be accomplished by using proper perforation penetration or creating fractures. Thus the prediction of invaded zone is critical and a numerical model can be used for preplanning purposes.

In this study, the dynamic filtration process and the related penetration into the gas and oil bearing reservoirs are studied in a vertical openhole system using a Computational Fluid Dynamics (CFD) software package. The radius of filtrate invasion is determined by the unsteady-state three-dimensional multiphase fluid flow model. This study investigates the communication between fluids and formations during drilling with special emphasis on the effects of formation porosity and permeability, time, and overbalanced pressure. As drilling fluids Non-Newtonians such as Bingham plastic, Power-law, and Herschel-Bulkley fluids also considered in addition to Newtonian fluids. Mud filtrate invasion in multi-layer reservoirs model and effect of hydraulic fracturing operations are also investigated in this study.

The results provided an insight in the formation damage around wellbore and related reduction in the hydrocarbon flow due to altered fluid saturations. Accurate prediction of damaged zone around the wellbore will benefit different operations such as drilling fluids design, log interpretation, hydraulic fracturing and well completion.
Design, Execution, and Evaluation of a "Typical" Marcellus Shale Slickwater Stimulation: A Case History
Authors: Fontaine J. , Johnson N. , Schoen D.
Published: October 2008

In 2004 the first Appalachian Basin Marcellus Shale gas well stimulation utilizing a large slickwater treatment was performed in southwestern Pennsylvania. Since that time, based upon various publically reported results, it has become the most widely discussed play in the basin with numerous operators drilling and completing Marcellus wells in Pennsylvania, West Virginia, Ohio, and New York. This wide geographic range has led to numerous different completion schemes being utilized as with geographic variation comes geologic variability within the formation itself. A primary topic of discussion has been determining the optimal size and type of stimulation treatment for a given area. This paper will discuss the stimulation treatment designed and performed on a Marcellus well operated by Guardian Exploration LLC.
A Look Into Casing Deformation Due to Plastic Behavior of Formations
Authors: Sunal O. , Bilgesu H. I. , Heasley K. A. , Tulu I. B.
Published: October 2008

A successful drilling operation at a location depends on the selection of proper hardware and optimum operating conditions. An important part of the hardware design is the selection of the casing based on estimated downhole conditions of pressure forces. Reliable information about the downhole conditions at a drilling site is available during drilling that helps the design of casing strings. However, the conditions of the hardware later in the life of the well due to plastic behavior of formations are not well understood. Casing damage may occur due to overburden shear damage on localized horizontal planes or compaction of the reservoir.

In this study, we investigated the behavior of plastic formations and the related impact of horizontal stresses on the casing in a wellbore. In an effort to understand the casing buckling due to plastic behavior of formations, a numerical model is used to study the forces on casing. Our approach uses a finite difference program to investigate the effect of horizontal stress on the casing for different formation characteristics, cement thicknesses, off-center casing configuration and anisotropic stress conditions.

The simulation shows rock behavior under vertical loading, including stress propagation inside the rock, deformation and damage evolvement as well as how cemented casing behaves under these conditions.
Compositional Simulation and Optimization of Secondary and Tertiary Recovery Strategies in Monument Butte Field, Utah
Authors: Wang J. , McVay D. A. , Ayers W. B.
Published: October 2008

Monument Butte field produces oil from low-permeability, lacustrine fluvial-deltaic sandstones of the Green River formation. Reservoir sands are heterogeneous, lenticular, and have limited aerial extent and vertical communication, resulting in poor inter-well connectivity. Cumulative recovery to date (primary and secondary) is about 2% of the estimated 2 billion barrels of original oil in place (OOIP). Current water flooding successfully maintains reservoir pressure, but it provides very poor sweep efficiency. The objectives of this study were to assess secondary and tertiary recovery methods and to recommend a reservoir management approach that would increase oil recovery efficiency. To accomplish these objectives, we conducted detailed compositional simulation studies in a pilot area of the field.

The reservoir model was calibrated using manual and assisted history matching methods. To reduce simulation time, we grouped fluid components into 10 pseudo-components. The 3-parameter, Peng-Robinson equation of state (EOS) was used to match PVT experimental data. Primary-then-water-flood and water-flood-only strategies were simulated using different water-flood timings. Infill drilling potential was evaluated by simulating downspacing from the original 40-ac to 20-ac well spacing. Immiscible and miscible flooding with CO2, water alternating with gas (WAG), N2, and CH4 were simulated with reservoir pressures below and above minimum miscibility pressure (MMP).

Simulation results indicate that water flooding should be started within 6 months of production. A water-flood-only strategy provides more oil recovery than a primary-then-water-flood strategy. Infill drilling may effectively produce unswept oil and double oil recovery. Immiscible gas injection suffers early gas breakthrough and is not an effective way to increase ultimate oil recovery. CO2 injection is much more efficient than N2 and CH4 injection, because it has a lower MMP (2500 psia) and later gas breakthrough. Water-alternating-CO2 injection is superior to continuous CO2 injection in oil recovery, because it makes the gas-oil mobility ratio more favorable, controls early CO2 breakthrough and maintains reservoir pressure. The study results can be used to optimize oil production from other parts of the large Monument Butte field.
Fracture Conductivity Loss Due to Geochemical Interactions Between Man-Made Proppants and Formations
Authors: Weaver Jim , Rickman Richard , Luo Hongyu
Published: October 2008

The selection of proppant to provide highly conductive pathways in hydraulically generated fractures is typically based on the proppant crush strength, permeability, availability, and cost. Extensive libraries of laboratory determined conductivity values, obtained using API standardized methods at a variety of simulated well conditions, are available for most proppants. However, post-fracture stimulation well testing indicates that these values are often one to two orders of magnitude too high. In many fields, the productivity of fractures declines rapidly, requiring frequent re-stimulation treatments to remain economically viable.

Proppant crushing and embedment, fracturing fluid damage, and fines invasion are proppant-pack permeability damage mechanisms that have been used to explain this loss of productivity. This paper reports on recent studies that have determined that aluminum-based proppant materials may promote geochemical reactions that can occur at a surprisingly rapid rate, even at moderate temperatures, resulting in the loss of porosity and permeability and the creation of fines in the proppant pack.

The compatibilities of several man-made proppants ranging from lightweight ceramics to high-strength bauxites with a variety of formations are presented. These findings indicate that the formation mineralogy plays a heretofore unrecognized role in determining proppant suitability. Most proppants were found to lose 50–60% permeability before stabilizing, while others were shown to lose up to 90% in only a few days.

This paper describes the specialized methods that were developed to study these geochemical reactions and reports quantitative changes in permeability, proppant composition, and fluid changes. Surface analysis using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) provides dramatic visual confirmation of this damage mechanism.

Results of this study have a great potential economic significance, suggesting new, important fracture design parameters that need to be determined to enable choosing the appropriate proppant for maximized stimulation longevity.
Gas or Oil Producer? Layered? Laminated?—Basic Guiding Principles We Should Understand for Effective Fracture Stimulation
Authors: McDaniel B. W.
Published: October 2008

Sometimes we dive too quickly into the smallest of details when trying to plan for fracture stimulation applications in our industry. It has been too often that a frac design engineer will gloss over the importance of unknown or missing reservoir data but spend many hours chasing the "exact-best" value to use for the treating fluid viscosity in the frac design simulator. Some reservoirs we frac routinely and understand how fracturing is best applied, and a few where we can choose the full scientific approach and monitor with microseismic listening. When there is just no chance to know accurate reservoir data, we may have few design options. However, it seems more often the case that the "frac design world" simply does not search out important data available within the geologist-geophysicist realm. The available pseudo-3D and numerical 3D frac design simulator software available to us can be used as a crutch instead of a useful tool.

We can be a novice in frac design from our lack of experience, or because we do not understand how to use our experience in a new or different reservoir setting. In very recent years, we have witnessed many highly experienced "frac gurus" fail to understand how to apply their experience when moving to horizontal wellbore applications. This paper will offer guidance to the less experienced frac design personnel as to some of the more important basic concepts of integrating hydraulic fracturing applications to reservoirs or well completion plans where little experience currently exists. Some reservoirs have been evaluated and reported in our literature to near "overkill" proportions for vertical completions and then struggled to understand frac stimulation of horizontal completions. Within the large body of technical papers and texts, most have slighted the importance of two factors: Rock hardness and formation pore pressure of gas reservoirs. This paper will stress the importance of including these factors.

With record high oil prices, and in some markets, good gas prices, we are seeing the extension of hydraulic fracturing to areas and reservoirs where little or no "frac" experience exists. Additionally, our need to fracture stimulate when our wellbore is significantly deviated is starting to multiply in number and importance, both offshore and onshore. This paper will be a valuable aid to this transition.
Using Reservoir Architecture To Maximize Co2 Storage Capacity
Authors: Riestenberg D. E. , Koperna G. J. , Kuuskraa V. A. , Esposito R.
Published: October 2008

This work explores, using reservoir simulation, the impact of reservoir architecture on CO2 plume movement and the reservoir's storage capacity. Subsurface flow of CO2 in the presence of shale "baffles", or lack thereof, will be reviewed in conjunction with other reservoir characteristics that influence flow such as formation dip, capillary pressure, pore volume trapping, and the rate of CO2 dissolution. Recent geologic and reservoir data collected from the Tuscaloosa Formation at the Mississippi Test Site (a Southeastern Regional Carbon Sequestration Partnership CO2 sequestration pilot test) will be used as the case study for evaluating alternative CO2 storage engineering concepts for maximizing CO2 storage capacity. The Tuscaloosa Formation is a thick, porous, permeable, regionally extensive saline reservoir occurring throughout the Gulf Coast and is considered a promising target for large-scale CO2 storage.
Evaluation of Skin Factor from Single-Rate Gas-Well Test
Authors: Aminian K. , Ameri S. , Almutairi F. , Brannon A.
Published: October 2008

Skin factor is commonly used as well flow efficiency indicator and the criterion for performing stimulation treatment to enhance well productivity. Skin factor, which is generally determined from interpretation of pressure transient well tests, is a composite factor and must be broken down into its various components in order to estimate near-wellbore damage. This is particularly important in the gas wells because they experience additional pressure drop near the wellbore due to high gas velocity. This additional pressure drop near the wellbore is generally referred to as non-Darcy effect and can be approximated by a rate-dependent skin factor. Therefore, the total skin factor obtained from a gas well pressure transient test has two primary components, rate-independent and rate-dependent skins. The rate-independent skin is primarily a function of formation damage, well deviation, completion, and perforation. Rate-dependent skin accounts for the non-Darcy effects. Both of these skins can be determined directly from the interpretation of pressure transient well tests if several transient tests at different rates were conducted. The multi-rate tests are however cumbersome to conduct and it is advantageous to estimate the rate-independent skin factor from a single rate test. In order to obtain a reliable value for the rate-independent skin from a single-rate test, the rate-dependent skin must be evaluated independently. The rate-dependent skin depends, among other parameters, on the coefficient of inertial resistance, β. A number of correlations relating β to permeability are available in the literature. These published correlations are derived from limited set of laboratory measurements on various porous media. Our previous investigations have revealed that these correlations do not provide consistent results. Alternatively, β can be determined from the results of the multi-rate well tests. The calculated β values from such tests reflect the actual field conditions that cannot be replicated in the laboratory. However, the complex dependency of β on the properties of the porous media precludes development of a single β -k correlation that can provide accurate and consistent results in all reservoirs. A more realistic approach would be to develop a relation between permeability and β for a specific porous media. To develop a correlation for β, a database of multi-rate gas well tests was established which contained data from over 100 well tests obtained from a number of operators in the Appalacian Basin. The well tests from several wells in the same reservoir were available and several field-specific correlations for β were developed. The comparison of skin factor determined from these correlations against the skin factors determined from the well test data indicated that reservoir-specific correlations for β provide accurate and consistent results.
Formation Evaluation Logging While Drilling (LWD) in Unconventional Reservoirs for Production Optimization
Authors: Quinn T. H. , Dwyer J. , Wolfe C. , Morris S. , Coope D.
Published: October 2008

Formation evaluation (FE) while drilling is an established technique in horizontal well orientations for unconventional reservoirs such as the Barnett Shale. Due to constrained well economics, special care is taken to acquire cost-effective information quickly to maximize lateral wellbore effectiveness. Real-time data and rapid analysis provide rock parameters impacting completion decisions. New technologies are discussed that further benefit our understanding of the reserve potential and improve asset economics. In particular we will discuss innovative applications of LWD imaging, LWD magnetic resonance (MR), and full-bore coring.

One key evaluation technology to optimize stimulation design is imaging-while-drilling to determine natural fracture system orientation and density and to distinguish J1 and J2 fracture sets and fractures that are potentially open. Images also provide input into geomechanical models that are used to plan stable wellbores and optimize stimulation treatments.

Innovation in LWD NMR applications allows quantification of porosity, irreducible and clay bound water in real-time. When combined with LWD bulk density, the total organic carbon content and static rock mechanical properties can also be computed optimizing well placement and completion design. It is shown that the integration of LWD imaging, MR and other LWD logs can improve the understanding of unconventional reservoirs.
Search Costs in Identity-Preserved Agricultural Markets
Authors: Reimer Jeffrey J
Published: October 2008

Many industries have "match-maker" institutions that help agents make links to one another by reducing search costs. Such institutions are now emerging in niche farm and food markets. In this study I provide an explanation for such institutions with a theoretical model of a niche market channel involving a small producer, retailer, and variety-loving consumer. I focus on the process by which producers are connected to retailers, and show that search costs between producers and retailers can be an important fixed cost of entry. Reduced search costs result in a larger number of matches, and facilitate the growth of niche market channels selling on the basis of producer identity. I examine the role of consumer preferences, retailer bargaining power, and other key features of these markets.
Anti-Adipogenic Activity of Capsicum annum (Solanaceae) in 3T3 L1
Authors: M Arumugam , P Vijayan , C Raghu , G Ashok , SA Dhanaraj , CT Kumarappan
Published: October 2008

Various extracts of Capsicum annum L were screened for their cytotoxicity and antiadipogenic activity in vitro. In cytotoxic studies all the extracts were screened against the 3T3 L1 cell line. Micro titre tetrazolium (MTT) and sulpho rhodamine B (SRB) assays against the 3T3 L1 cell line determined cytotoxicity. Methanol extract of fruit showed higher cytotoxicity with a lower CTC50 value of 167.46 µg/ml and the remaining extracts show CTC50 ranging from 180-282 µg/ml. In 3T3 L1 cells dexamethazone, 3- isobutyl-1-methyl xanthine (IBMX) and insulin, induced adipogenesis. All the four extracts (methanolic and water extracts of whole plant and fruit) were screened for their antiadipogenic activity in 3T3 L1 cell line; the methanolic fruit extract showed good antiadipogenic activity at 100 µg/ml.
The University Press in North America: A Brief History
Authors: Jagodzinski Cecile M.
Published: October 2008

This article traces the history of university presses in North America, from the founding of the first presses at Cornell University and Johns Hopkins in the last quarter of the nineteenth century to the present. The growth of colleges and universities and new imperatives that faculty engage in productive research helped shape the function of the modern university press. In the twentieth century, smaller subsidies from parent institutions, new developments in technology, and the erosion of library budgets affected the stability of many presses and forced many to revise both their editorial goals and their business and management practices. Faced with new modes of scholarly communication, the explosion of digital publishing, and the open-access movement, university presses will need to continue to adapt and to assert their proper role in the scholarly community.
The Scholarly Book Buyer's Decision Process: A National Survey of University Faculty Members in the United States
Authors: Estelami Hooman , Greco Albert N. , Wharton Robert M.
Published: October 2008

This article reports on a national survey of university faculty members in the United States regarding the factors that influence their purchases of scholarly books. In total, 233 faculty members from eleven disciplines in more than fifty universities were surveyed. The survey gauged the impact of a series of factors that influence scholarly book purchases for research and teaching. In addition, sources of information used to locate scholarly books of interest were identified and contrasted across fields of study. The survey also examined trends in the respondents’ book-buying behaviour, their propensity to purchase used books, and the frequency with which they used university library systems to obtain access to scholarly books.
Use of Outcome Measures in Physiotherapy Practice in Ireland from 1998 to 2003 and Comparison to Canadian Trends
Authors: Stokes Emma K. , O’Neill Desmond
Published: October 2008

Purpose: The purposes of this study were to examine changes in the use of standardized outcome measures by practising physiotherapists in Ireland and to compare those trends to the results of a similar survey conducted previously in Canada.

Method: A survey methodology was employed. The review of practice occurred at two points in time. Senior clinical physiotherapists working with older people participated. Questions were asked about the use of standardized outcome measures, the nature and pattern of their use, and the level of confidence the respondents had in using such measures.

Results: The results chart the changes in practice over a 5-year period. Although there was an increase in the use of standardized outcome measures, the respondents acknowledged barriers to their systematic use in routine practice (e.g., lack of time, resources/administrative support). There was a lack of professional consensus on what instruments to use in general, as well as which to use for particular client groups. Concern was expressed that none of the available instruments met their clients’ needs. Where possible and appropriate, comparison was made between the data from the 2003 Irish study and a survey of Canadian physiotherapists conducted in 1998.

Conclusion: This review of practice illustrates that changes that have occurred in Ireland in the use of standardized outcome measures are similar to those that have occurred in Canada, but barriers remain to their complete integration into clinical practice and clinical decision making.
Self-Assessment: The Disconnect between Research and Rhetoric
Authors: Miller Patricia A.
Published: October 2008

Purpose: Physical therapists are expected to engage in self-assessment in order to ensure competent practice and to identify appropriate professional development activities.

Summary of Key Points: This paper reviews the current literature on the accuracy and role of self-assessment in physical therapy. Current literature indicating that self-assessment cannot be conducted with any degree of accuracy is discussed, and a proposed reformulation of the concept of self-assessment is presented.

Recommendations: Practical strategies are offered for clinicians to improve the potential for obtaining reliable and valid information about their own clinical performance to guide the selection of appropriate professional development activities and to promote the provision of competent patient care.
Effects of Exercise Interventions on Stereotypic Behaviours in Children with Autism Spectrum Disorder
Authors: Petrus Christopher , Adamson Sarah R. , Block Laurie , Einarson Sarah J. , Sharifnejad Maryam , Harris Susan R.
Published: October 2008

Purpose: The purpose of this systematic review was to synthesize evidence from studies examining the effect of exercise interventions on stereotypic behaviours in children with autism spectrum disorder (ASD).

Methods: Only exercise-related physical therapy (PT) interventions were included. A multifaceted search strategy identified studies published between 1980 and 2007. Quality was assessed using the American Academy of Cerebral Palsy and Developmental Medicine (AACPDM) Study Quality Scale, the Clinical Relevance Tool for Case Studies, and the Quality, Rigour or Evaluative Criteria tool.

Results: Seven studies (1982–2003) met our inclusion criteria; four of these used single-subject research designs, two were group studies, and one was a case study. Ages and behavioural characteristics of the children (N = 25) varied among the studies. Levels of evidence ranged from II to V (of a possible I–V). Study quality scores ranged from 2 to 5 (range: 0 to 7); mean = 3.9, mode = 5. Few studies in this area of PT practice have been published, and those identified scored low levels of rigour on the AACPDM criteria.

Conclusions: Research suggests that exercise provides short-term reductions of stereotypic behaviours in children with ASD. Future research with stronger evidence levels, greater rigour, and longer-term outcome assessment is required to determine specific exercise parameters.
Eccentric Exercise in Patients with Chronic Health Conditions: A Systematic Review
Authors: Roig Marc , Shadgan Babak , Reid W. Darlene
Published: October 2008

Purpose: The capacity of eccentric actions to produce muscle hypertrophy, strength gains, and neural adaptations without stressing the cardiopulmonary system has led to the prescription of eccentric training programmes in patients with low tolerance to exercise, such as elders or those with chronic health conditions. The purpose of this systematic review was to analyze the evidence regarding the effectiveness and suitability of eccentric training to restore musculoskeletal function in patients with chronic diseases.

Summary of Key Points: Relevant articles were identified from nine databases and from the reference lists of key articles. Articles were assessed to determine level of evidence and scientific rigour.

Nine studies met the inclusion criteria. According to Sackett's levels of evidence, 7 studies were graded at level IIb, 1 study at level IV, and the remaining study at level V. Articles were also graded for scientific rigour according to the PEDro scale. One study was rated as high quality, 4 studies were rated as moderate, and 2 studies were graded as poor quality.

Conclusions: Eccentric training may be safely used to restore musculoskeletal function in patients with some specific chronic conditions. However, the heterogeneity of diseases makes it very difficult to extrapolate results and to standardize clinical recommendations for adequate implementation of this type of exercise. More studies are needed to establish the potential advantages of eccentric training in chronic conditions.
Efficacy of Postural and Neck-Stabilization Exercises for Persons with Acute Whiplash-Associated Disorders: A Systematic Review
Authors: Drescher Kara , Hardy Sandra , MacLean Jill , Schindler Martine , Scott Katrin , Harris Susan R.
Published: October 2008

Purpose: We systematically reviewed randomized and quasi-randomized clinical trials in the literature to assess the efficacy of neck stabilization and postural exercises on pain, neck range of motion, and time off work in adults with acute whiplash-associated disorders.

Methods: Electronic databases, reference lists of relevant Cochrane reviews, reference lists of studies selected for inclusion, and tables of contents of relevant journals were systematically searched for randomized and quasi-randomized controlled trials. Two independent reviewers selected studies for inclusion, assessed methodological quality, and extracted data. Because of the heterogeneity of the interventions, a qualitative synthesis was performed using “levels of evidence” as recommended by van Tulder et al.

Results: Eight studies representing five clinical trials were selected for inclusion. Two trials were graded as high quality, two as moderate quality, and one as low quality. Many of these studies had mixed results, demonstrating significant differences on some outcome measures but not on others.

Conclusions: There is moderate evidence to support the use of postural exercises for decreasing pain and time off work in the treatment of patients with acute whiplash-associated disorders. However, no evidence exists to support the use of postural exercises for increasing neck range of motion. There is conflicting evidence in support of neck stabilization exercises in the treatment of patients with acute whiplash-associated disorders.
Clinical Specialists and Advanced Practitioners in Physical Therapy: A Survey of Physical Therapists and Employers of Physical Therapists in Ontario, Canada
Authors: Yardley Darryl , Gordon Robert , Freeburn Ryan , So Colleen , Beauchamp David , Landry Michel D. , Switzer-McIntyre Sharon , Evans Cathy , Brooks Dina
Published: October 2008

Purpose: Opportunities to expand the role of physical therapists (PTs) have evolved to include clinical specialists and advanced practitioners, although the literature on these roles is limited. We examined perceptions of PTs and PT employers in Ontario regarding clinical specialization and advanced practice.

Methods: Using a modified Dillman approach, a cross-sectional survey was conducted with 500 PTs and 500 PT employers in Ontario. Questionnaires were tailored to address specific issues related to each cohort.

Results: Sixty percent of PTs and 53% of PT employers responded to the survey. Thirty-three percent of PT respondents already considered themselves “clinical specialists” (CS), and 8% considered themselves “advanced practitioners” (AP), although neither role is yet formally recognized in Canada. Both groups had substantial interest in pursuing formal recognition of CS and AP status. Respondents indicated that their primary motivation to pursue such roles was to enhance clinical reasoning skills with the goal of improving client outcomes (82% for the role of CS, 71% for the role of AP). Respondents supported the involvement of academic institutions in the process (60% for CS, 70% for AP).

Conclusion: PTs and PT employers are supportive of the roles of the CS and AP within the profession, even though there is currently no formal recognition of either role in Canada.
Pain Profiles and Psychosocial Distress Symptoms in Workers with Low Back Pain
Authors: Mngoma Nomusa , Corbière Marc , Stevenson Joan
Published: October 2008

Purpose: The current study investigated the pain profiles of patients with subacute non-specific low back pain attending an outpatient return-to-work rehabilitation programme. Differences in symptoms of distress (depression and anxiety) and return to work between the pain-profile groups were assessed.

Methods: Sixty-five volunteers who met the eligibility criteria and had complete follow-up data were included in the analysis. The mean age was 38.8 years (minimum 18, maximum 64); 38 (58.5%) were men. The median time since onset of low back pain was 30 days. Cluster analysis was used to categorize patients into groups according to pain severity scores (VAS).

Results: Two distinct clusters—severe pain and moderate pain—emerged. There were significant differences in depressive and anxiety symptoms between the pain profiles. Further, return-to-work rates varied significantly between the two groups (31% in the severe pain cluster compared to 90% in the moderate pain cluster).

Conclusion: Although both groups showed significant improvements in depression and anxiety symptoms over time, the severe pain cluster scored higher at discharge (higher scores indicating worse outcomes). These results highlight the importance of early identification of sub-groups at risk so that rehabilitation interventions can be focused with the goal of minimizing long-term disability.
Measurement Properties of Performance-Specific Pain Ratings of Patients Awaiting Total Joint Arthroplasty as a Consequence of Osteoarthritis
Authors: Halket Ashley , Stratford Paul W. , Kennedy Deborah M. , Woodhouse Linda J. , Spadoni Gregory
Published: October 2008

Purpose: To estimate the test–retest reliability of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain sub-scale and performance-specific assessments of pain, as well as the association between these measures for patients awaiting primary total hip or knee arthroplasty as a consequence of osteoarthritis.

Methods: A total of 164 patients awaiting unilateral primary hip or knee arthroplasty completed four performance measures (self-paced walk, timed up and go, stair test, six-minute walk) and the WOMAC. Scores for 22 of these patients provided test–retest reliability data. Estimates of test–retest reliability (Type 2,1 intraclass correlation coefficient [ICC] and standard error of measurement [SEM]) and the association between measures were examined.

Results: ICC values for individual performance-specific pain ratings were between 0.70 and 0.86; SEM values were between 0.97 and 1.33 pain points. ICC estimates for the four-item performance pain ratings and the WOMAC pain sub-scale were 0.82 and 0.57 respectively. The correlation between the sum of the pain scores for the four performance measures and the WOMAC pain sub-scale was 0.62.

Conclusion: Reliability estimates for the performance-specific assessments of pain using the numeric pain rating scale were consistent with values reported for patients with a spectrum of musculoskeletal conditions. The reliability estimate for the WOMAC pain sub-scale was lower than typically reported in the literature. The level of association between the WOMAC pain sub-scale and the various performance-specific pain scales suggests that the scores can be used interchangeably when applied to groups but not for individual patients.
Development of a Walking Safety Scale for Older Adults, Part I: Content Validity of the GEM Scale
Authors: Kaegi Christine , Boudreault Renée , Rousseau Jacqueline , Bourbonnais Daniel , Nadeau Sylvie , Dubé François
Published: October 2008

Purpose: The Grille d’évaluation de la sécurité à la marche (GEM scale) is a performance-based tool developed to fill the need for an objective assessment of walking safety for older adults. It underwent a three-phase process of content validation.

Method: A mailed questionnaire was used to assess the representativeness of the walking items (5-point pertinence scale). Subsequently, two physiotherapist focus groups (n = 20) were held to further evaluate the relevance of the scale and the walking items. Finally, a pilot study was completed with 3 raters administering the GEM scale to 12 hospitalized patients.

Results: Comments and descriptive statistics (percentages) were analyzed from the questionnaire results and focus groups. On completion of the pilot study, which assessed 12 patients on the GEM scale, additional analyses were performed to address the theoretical background, the administration manual, the walking items, the scoring scale, and interpretation of the scale. Following each step, modifications were made to reflect the results of the analyses.

Conclusion: The three-phase content-validation process demonstrated the relevance of this instrument and its representativeness as a walking safety assessment tool for older adults.