bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Sand Cleaning Algorithms for Planning and Executing Electric Wireline Suction Tool Operations
Authors: Nunez W. , Perez L. , Schwanitz B.
Published: March 2013

Conventional methods used for downhole sand or debris cleaning have considerable investments in economic costs and time. Scheduling these activities to minimize production interuptions and to maximize unrestricted flow is a constant challenge faced by production and flow assurance engineers in the Oil & Gas industry. A sand and fill cleaning decision can be expressed as an optimization problem since its purpose is to maximize the production of the well to accomplish production goals at the end of a time period.

This paper presents optimization algorithms applied in dynamic programming to help in scheduling cleaning interventions for wells in order to maximize the continuous production under physical, technical and economic considerations while minimizing the investment cost of the total operation. A strategy will be presented which takes into account mainly the fixed costs but also the variable costs and sensitivity analysis that allow the model to better approximate reality. The strategy considers three options based on the costs of cleaning with either electric line or coiled tubing technology; 1) to completely remove a given volume of sand, 2) to clean to a minimum acceptable level or, 3) not to clean and allow sand volume increases to continue.

The cost to perform sand cleaning with a certain technology based on a mathematical function, considers the following requirements:the relationship between volume of sand produced per unit time, Vt (flow),(Vmax-Vmin) or the interval between Vmax in which production of oil is minimized and the Vmin for maximum production,the time horizon to perfom the sand cleanings, andPoints that make the operation unfeasible such as physical restrictions in the well or operator time/cost constraints.

This paper will also present two cases demonstrating the strategy to schedule cleaning interventions that achieves a set production goal.
Break the Friction: Chew the Plug for Faster Completions on Coiled Tubing
Authors: Gilbert Landry G. , Skyles Lane P. , Smith Lee M. , Davis Gary W. , Medlin Kevin G.
Published: March 2013

Once the decision is made to complete a well in order to begin producing, the operator wants to complete the task as soon as possible. One completion task is to drill through multiple completion plugs so the pay zones can begin producing. In the past, drilling these plugs has gone slower than desirable due to static friction build-up between the coiled tubing string and the hole wall. In addition, slower plug drilling results as the drill bit dulls after drilling several plugs.

This paper introduces a friction breaking tool/drill bit combination that has shown to lessen plug drilling time by almost double what was previously possible. The friction physics between hole wall and coiled tubing will be presented in the initial portion of this paper. Then, the simple designs of the friction breaking tool and the drill bit will complete the design portion of the paper. Finally, a Case Study is provided to show the results of running these tools. The Case Study took place in Tarrant County, Texas while drilling out composite completion plugs to complete four wells.
Accelerating the Learning Curve: Adapting Global Expertise to Coiled-Tubing Operations in Argentina Shale Development
Authors: Sergio J. , García R. , Moll Juan M. , Olivas José , Nebiolo Martin Mauro
Published: March 2013

World energy demand has led unconventional reservoirs to become a focal point for operators worldwide. In some regions, including North America, unconventional resources have been developed successfully, accumulating important experience and lessons learned in the process, allowing these resources to become important contributors to countries’ energy production. In an attempt to reproduce this effect in other regions, operators are also looking into important unconventional reservoirs outside North America. Currently the world’s third-largest shale oil and gas resources holder, Argentina has become a key focus for many operators initiating exploration and development operations. This brings many challenges to operators trying to take over this market as quickly, efficiently, and safely as possible.

When developing unconventional reservoirs in the magnitude expected, one of the most important challenges for service companies and operators in Argentina is effectively grasping the global expertise, best practices, and lessons learned from these types of operations and adapt them to the local environment. This should reduce the learning curve experienced while starting a new development. A key component of these challenges includes all coiled tubing (CT) interventions involved in well completion; expertise in CT intervention is critical because of the risks concerning these operations, which include wellbore calibration, perforating, fracture plug drillouts (FPDOs), and sand cleanouts. Overcoming this challenge can translate into valuable time and cost reductions and allow operators to reach the efficiency that took years to attain in other parts of the world in much less time.

Lessons learned and best practices incorporated from global experience, in addition to the local ideas, contributed to the implementation of CT interventions for the shale startup and beginning of the development phase in Argentina. Statistics and results from jobs performed in these reservoirs in its first year since startup reflect the changes and adaptations undertaken to successfully develop the shale resources in Argentina and to inform future plans for this rapidly evolving market.
A Metallurgical Look at Coiled Tubing
Authors: Coloschi M. , Gomez G. , Mitre J. , Nguyen T. , Reichert B. , Valdez M.
Published: March 2013

Coiled tubing has been traditionally characterized by its mechanical properties in order to guarantee that the structural response of the tubing is uniform and satisfies current standards along its full length. Also the tubing is generally fatigued tested in order to characterize its responses under simulated field conditions. As coiled tubing applications become more challenging, there is a need for higher mechanical properties, better resistance to severe environments and a better relative fatigue performance in the tube body and bias weld. The limitations to develop a product that satisfies these new requirements can not be understood solely based on coiled tubing mechanical properties, but extensive metallurgical analysis must be performed.

In this study, the relevance of the metallurgy basis in each of the production steps was reviewed in order to understand the limitations of current manufacturing process. This understanding, coupled with the goal of developing new products that satisfy new market demands, has resulted in a complete redesign of the manufacturing process. Preliminary results of a new manufacturing process have proven to provide a path for current and future innovative products.
Using Electric-Line Tools To Clean Wellbore Laterals and Perforate Toes
Authors: Gomez L. D. , Miller N. , Binnion K.
Published: March 2013

Coiled tubing (CT) is invaluable equipment in shale oil/gas completion operations. From well cleanout to perforating and fracturing operations, CT does it all. However, with the boom in shale oil/gas development and the number of wells required to develop these unconventional resources, demand and cost for CT can be high and often availability can be limited.

In an effort to reduce completion costs and minimize CT use, reserving it for only those tasks that absolutely require it, an operator in the Eagle Ford shale decided to investigate alternative technologies for performing post-cementing well cleanup and toe perforating. The operator was aware of an electric-line (e-line), tractor-conveyed cleaning tool with a reverse circulating bit (RCB) that was being used for drifting and cleanout runs. These tools have been used successfully in Norway and Canada, offshore and on land, to clean out cement stringers and other debris from the wellbore, ensuring a clear path for the toe perforations, which follow. With these tasks successfully completed, the pumping down of frac plugs can be accomplished with confidence during multi-stage completion operations.

The operator decided to try the e-line technology on a five-well pilot project of cased, horizontal wells in the Eagle Ford development. This was the first time the technology was used in U.S. land operations. The e-line cleaning tool cleaned the wells, and the tractor-conveyed perforating guns reached the depth cleaned out by the e-line cleaning tool. On this pilot project, the average field time per well for an e-line cleanout and tractor-conveyed toe perforation was 24 hours. The pilot test was considered a success.

This paper discusses the details of the project and tool operations for each well, and the lessons learned and applied to each successive well in the pilot to develop a successful strategy for using these tools across a broad range of operating conditions.
Feasibility Study of Underbalanced Drilling Using Coiled Tubing (CT-UBD) : A Case Study Field "A", Indonesia
Authors: Marbun B. T. , Arliyando L. , Sinaga S. Z. , Arimbawa G. V.
Published: March 2013

Field "A" in Indonesia will be drilled dual lateral using underbalanced drilling technique. The reservoir has been highly depleted, low reservoir pressure about 1130 psi and high bottom hole temperature about 350°F. This field produce natural gas and condensate which contain 80-100 ppm H2S, 15% CO2 and water. Underbalanced drilling will be conducted to minimize the potential problems by utilize Coiled Tubing and nitirified mud.

Coiled Tubing Drilling (CTD) has reached its popularity in last two decades. In principle, CTD provides hydraulic horsepower which is transfered to the bottomhole. In operation, CT has advantages and disadvantages compared to jointed pipe. CT Unit (CTU) are complete package consists of surface and subsurface equipments.

Underbalanced drilling has several advantages: to minimize problems, such as lost circulation, pipe sticking, formation damage, etc. From several drilling fluid, only two types are available in this field and nitrified mud is choosen for several reasons and based on qualitative method regarding factors: wellbore diameter, water influx, gas production, and Extended Reach Drilling (ERD). Gas injection methods are also reviewed.

Combination of CTD and underbalanced drilling, which is dual lateral drilling, delivers maximum productivity improvement compared to single lateral. This is obtained from well performance study or upflow performance study from existing wells. This study is conducted to estimate productivity improvement for various lateral configurations, liner diameter, and well position.

This paper discusses the multiphase flow modelling of underbalanced drilling in Field "A" to determine operational drilling parameters, to select effective drilling fluid and to select CT string and BHA. The main concerns are the challenging conditions in Field "A": 1). High temperature, 2). Corrosive environtment, and 3) Requirement of effective drilling fluid. The outcome of this paper is to provide analysis of upflow performance study, operational window parameters, optimal drilling fluid, and CT string and BHA.
To Mill or Not to Mill: A Fully Retrievable Multistage Fracturing System
Authors: Griffin John , Barraez Rair , Campbell Sean
Published: March 2013

With the increase in horizontal wellbore lengths, effective hole cleaning and efficient milling practices play a critical role in coiled tubing (CT) extended reach applications. Multistage hydraulic fracturing of unconventional reservoir plays has focused horizontal completion techniques on one of two primary types: plug-and-perf or ball-and-seat liner systems. The introduction of ball-and-seat technology in the middle of the last decade was a breakthrough in the horizontal stimulation completion process and significantly impacted the ability of operators to economically develop shale and tight oil reservoirs.

Most current completion systems require post-fracturing milling interventions to restore full wellbore access and remove flow restrictions. To address the challenges associated with plug milling or opening ball seats up to the full liner drift diameter, fully retrievable single-trip systems have been developed. These next generation systems require no post-stimulation milling or drilling while maintaining the benefits of both the plug-and-perf and the ball-and-sleeve completion methods through the use of retrievable isolation plugs and ball seats. Workover time can be decreased over 40%, eliminating costly milling operations. The uncertainty in both milling efficiency and the removal of debris is replaced with a simple set-down and release mechanism which leaves the wellbore unobstructed for any future well interventions. The retrievable seat system has the added advantage of leaving behind a shiftable sleeve which can be activated numerous times.

Over 600 stages of the retrievable seat system have been successfully installed and retrieved within the last 12 months while providing operators the future ability to shut off zones which may unfavorably affect production by water or gas break through. This paper will address sleeve and plug retrieval versus milling, comparing job times, cost, operating efficiencies and equipment requirements.
A Chronological Review of Concentric Coiled Tubing Vacuum Technology: Past, Present and Future
Authors: Pineda Rodolfo , Lindsey B. J. , Taggart Michael , Smith Simon , Ababou Mounir
Published: March 2013

Concentric Coiled Tubing Vacuum Technology (CCTVT) was developed in the mid 1990s in Canada, and since then has spread worldwide. The technology was initially focused on sand cleanouts in heavy-oil, low-pressure, deviated wells, where other cleanout methods, including conventional CT interventions, were inefficient. Under such conditions, CCTVT provided a simple but very effective solution.

In general terms, the technology comprises a downhole jet pump run on a concentric coiled tubing (CCT), which is a coiled tubing string inside another coiled tubing string. A single-phase fluid is pumped through the inner string to power the downhole jet pump, creating a localized drawdown that vacuums well fill (fluids and/or solids), increases the return pressure, and circulates fluids and solids back to surface via the CCT annulus.

Since the introduction of this technology, it has gone through several updates in order to face new challenges. The latest BHA versions include multiple operational modes to improve cleanout efficiency, minimize runs, function with supplementary tools and most recently, to accommodate a specialized electric conductor to run a real-time logging tool in conjunction with the jet pump.

Currently, the application of the system has extended beyond solids removal on heavy oil, onshore wells. The current work scope ranges from very simple operations such as drilling fluid and filter cake removal, liquid unloading, inflow profiling, evaluating completion integrity, matrix stimulation, pressure and temperature logging, etc.; to more complex and challenging operations such as memory production logging, H2S inhibition, multilateral wells, chemical sand consolidation, hydrate removal and realtime production logging. These operations are occurring in the full range of oilfield locations: onshore and offshore wells, from fixed installations to mobile rigs, in jungle to arctic conditions.

This paper will summarize the new techniques that are being applied in many global locations with CCTVT. Each technique will be illustrated with case histories detailing time and cost savings and, where relevant, production improvements.
New Coiled Tubing Pipe Failure Mechanism Identified in Severe Dynamic Conditions - The Potential Effects of Running Speed on pipe Performance
Authors: Cano Valeriano , Reichert Bruce , Grimaldo Carmen , Addison Ryan
Published: March 2013

The use of large-diameter coiled tubing (CT) pipe, 2 inches and greater, as the typical work strings in HP/HT extended reach wells has brought new challenges to the CT intervention industry. The CT strings utilized in this service are expensive and, by nature, short-lived expendables. As well reach increases, the strings become increasingly more sophisticated and costly. Identifying, predicting and controlling the factors that govern the pipe reliability is important to further extend the usable life of strings and contribute to the operational and economical success of CT service providers, CT pipe manufacturers and O&G operators.

Furthermore, if any CT failure takes place, the root cause investigation is essential to the continuous improvement of the service and must be looked at in a holistic, systematic manner [1][2][6]. Hence we must understand how the combination of operational procedures, surface equipment, CT pipe manufacturing, and overall well conditions can affect pipe performance.

In this proactive process, a new mechanism that can contribute to failures has been identified. This failure mode is associated with larger outside diameter (OD) CT pipe being subjected to a combination of high hoop stresses, high strain levels and run-in or retrieved from wells at high speeds. These new set of operational dynamic conditions expose the CT pipe material to higher forces, stresses and deformations not considered in the traditional conventional working envelope and in the associated performance tests and models.

This new field CT pipe failure mechanism is presented in this work, its possible origins are explained in addition to laboratory test data reproducing such failures and identifying the potential set of combined operational conditions in which it can take place.

An alternative CT fatigue-data generation procedure is proposed to better predict pipe performance, avoiding failures under field conditions, improve operational procedures, and enhance overall service quality.
State-of-the-Art Portable Measurement and Defect Detection Technology for Coiled Tubing String
Authors: Zheng Andrew , Liu Zhanke , Zwanenburg Mirjam , Burgos Rex , Stayer Aaron
Published: March 2013

Most coiled tubing (CT) string failures in the field can be traced back to some initial defects, such as mechanical damage, a corrosion pit, a manufacturing defect, etc. Because of the ductility of CT, the introduction of these initial defects doesn’t normally cause failure at the onset. However, over the course of the service life, these initial defects evolve or grow until they reach a critical stage, leading to eventual failure. To assess the serviceability of a CT string, the industry has largely relied on periodic pipe inspection using magnetic flux leakage (MFL). Since MFL signals arise from a complex combination of defect geometry, defect severity, and material anomaly, etc. in the pipe wall, they are very difficult to interpret. A "snapshot" inspection of the string may not provide adequate information to fully evaluate its integrity and/or future serviceability.

To improve assessment of CT string serviceability, a new approach has been developed. The "continuous" inspection approach involves MFL monitoring of the CT string during utilization. With the continuous MFL monitoring from "new" pipe state through its entire service life, the MFL signal directly attributed to defects can be isolated and tracked, leading to an improved evaluation of the CT string’s condition and future serviceability. In conjunction with the theoretical fatigue life tracking, a new pipe Degradation Parameter is used to improve the management of aging coiled tubing.

The state-of-the-art portable measurement and defect detection technology for CT strings uses MFL to detect the existence of defects and to measure wall thickness. It uses eddy current technology to measure the outside diameter (OD) of the pipe. MFL measurements are used to evaluate the defects over successive operations. Wall thickness and OD measurements are used in a real-time software to update the CT working envelope and the fatigue life. By integrating these features into a small portable device suitable for real-time inspection, this technology significantly improves the ability to monitor overall pipe integrity.
The Value of Adaptive Regret Management in Retirement
Authors: Farquhar Jamie C. , Wrosch Carsten , Pushkar Dolores , Li Karen Z. H.
Published: March 2013

This 3-year longitudinal study examined the associations between regret management, everyday activities, and retirement satisfaction among recent retirees. We hypothesized that the regulation of a severe life regret can facilitate activity engagement and retirement satisfaction, but only if retirees manage their regrets adaptively by either increasing effort and commitment when possessing favorable opportunities or disengaging when opportunity is unfavorable. Cross-sectional analyses demonstrated that the highest baseline levels of activity (e.g., volunteering, traveling) and retirement satisfaction were observed among participants who perceived favorable opportunities for addressing their life regrets and had high levels of engagement. Longitudinal analyses showed that this pattern was also associated with increases in activity engagement. In contrast, disengagement protected individuals with unfavorable opportunity from 3-year declines in retirement satisfaction. These findings indicate that adaptive regulation of regrets can both contribute to gains and prevent losses in the early stages of retirement, which may have lasting consequences on retirees' quality of life.
Late Holocene Lithic Procurement Strategies in the Northwestern Great Basin: The View from Paiute Creek Shelter, Nevada
Authors: Smith Geoffrey M. , Lavalley Stephen J. , Wiggins Kristina M.
Published: March 2013

We present source provenance data from a sample of obsidian projectile points and unmodified flakes from Paiute Creek Shelter (PCS), a site in Nevada's Black Rock Desert that was first occupied 4,700 calendar years ago (cal BP). Significant differences between the source profiles of earlier (pre-1,450 cal BP) and later (post-1,450 cal BP) occupations suggest that toolstone procurement strategies changed over time at PCS. Before 1,450 cal BP, there was a heavy reliance on local toolstone directly procured from nearby sources. Although local toolstone remained important after 1,450 cal BP, non-local toolstone became more common at PCS, highlighting increased interactions with neighboring populations. The shift in toolstone use at PCS is but one of many changes in the archaeological record of the northwestern Great Basin after 1,500 cal BP.
Canadian Arctic Soapstone Cooking Technology
Authors: Frink Liam , Glazer Dashiell , Harry Karen G.
Published: March 2013

This article examines the thermal properties of soapstone in comparison to other materials, to help us explore why Arctic cooks might have elected to use this material for their cooking containers. Low energy water boiling experiments, designed to simulate the low energy, oil-based fuel technologies of the Arctic, were undertaken. The results indicate that compared to metal and ceramic containers, soapstone is better able to store heat. We propose that this property makes soapstone especially useful in Arctic environments, where fuel sources are limited and indigenous heating techniques commonly relied on low energy. By understanding how heat is absorbed into metal, ceramic, and stone containers and how it is subsequently released into water we gain important contextual insights into the technological choices made by Arctic people.
Investigation of the bainitic reaction in a CuAlNiMnFe shape memory alloy
Authors: Benke M. , Mertinger V. , Pekker P.
Published: March 2013

Despite their favorable properties, brittle nature of the CuAlNi shape memory
alloys limits their suitability. To increase their ductility, Mn and Fe were
added to the base CuAlNi alloy. To reveal the applicability of the developed
CuAlNiMn and CuAlNiMnFe alloys as functional materials, the effect of ageing
on the thermoelastic martensitic transformation was investigated. During the
first heating of the aged samples the thermoelastic ?? ? ? transformation
occurred, which was followed by a bainitic transformation. This
transformation inhibited the further thermoelastic martensitic
transformations. The present paper covers heat flux DSC, SEM, and TEM
investigations of the bainitic transformation. A feasible mechanism of the
bainitic transformation in these alloys is suggested based on the results of
the examinations.
Does a Lack of Choice Lead to Lower Quality? Evidence from Auditor Competition and Client Restatements
Authors: Newton Nathan J. , Wang Dechun , Wilkins Michael S.
Published: March 2013

We examine the relationship between auditor competition and the likelihood of financial restatements that occur as a result of failures in the application of generally accepted accounting principles (GAAP). Policy makers and audit market participants have expressed concern that the current level of auditor competition is low, resulting in a negative impact on audit quality. However, we find that restatements are more likely to occur in metropolitan statistical areas (MSAs) that have higher auditor competition. The association between audit market competition and restatements is statistically and economically significant. Our finding of a positive relationship between the likelihood of restatement and audit market competition is relevant to the ongoing debate regarding audit quality and the concentration of audit markets.
Accounting for the Public Interest: A Revenue Recognition Dilemma
Authors: Savage Arline , Cerf Douglas C. , Barra Roberta A.
Published: March 2013

This case illustrates how accounting rules impact the public interest and vice versa. The setting is a gray area of accounting in which management, the external auditors, the SEC, and international accounting standard setters may have differing opinions about the accounting treatment. Students consider the situation in which an accounting rule leads to a business and societal problem. They gain an understanding of how this happens and how such problems can be addressed. The context for this case is a revenue recognition issue for bill-and-hold sales. It also provides students with the opportunity to consider the real-world implications of accrual- versus cash-based accounting. This case is useful for intermediate- to graduate-level financial accounting classes or an accounting capstone class.
Dream Chocolate Company: Choosing a Costing System
Authors: Krumwiede Kip R. , Walden W. Darrell
Published: March 2013

This case is about a small, but real, company, Dream Chocolate (D.C.), which makes custom-labeled, high-quality candy bars for special events and advertising purposes. Like many small companies, D.C. has an inadequate costing system and needs a much better one as it starts to get bigger orders. In Part A of this case, students learn how to analyze a company's situation, identify relevant information in a case that is presented in a less-structured format, evaluate the pros and cons of different costing approaches, recommend an approach, and suggest ways to implement it. In Part B, they develop and calculate costs based on their recommended approach. The case also helps increase students' understanding of the applicability of various costing methods typically covered in cost and managerial accounting courses.
DISCUSSION OF: Divestitures of Equity by Executives and Future Equity Granting Patterns
Authors: Black Dirk E. , Dikolli Shane S.
Published: March 2013

Cadman (2013) finds empirically that in response to a CEO divestiture of ownership, boards impose higher compensation risk on CEOs via a higher magnitude of equity grants that are also a higher proportion of annual compensation. The intuition is that by divesting, the CEO diversifies personal wealth risk, which enables boards to impose more risk via variable compensation, over and above what conventional economic determinants would predict. The study highlights the difficulties associated with connecting conventional agency theory to standard empirical tests of the economic determinants of compensation and the importance of measurement in understanding personal wealth diversification. The study also has implications for tests of cross-sectional differences in the pay-for-performance relation associated with CEO divestitures.
Bracket base remnants after orthodontic debonding
Authors: Zanarini Matteo , Gracco Antonio , Lattuca Monica , Marchionni Silvia , Gatto Maria Rosaria , Bonetti Giulio Alessandri
Published: March 2013

Objective:

To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding.

Materials and Methods:

Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n  =  818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n  =  100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data.

Results:

Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P  =  .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P  =  .0001, respectively).

Conclusion:

The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.
Giant Cell Tumor of Bone in a Child with Goltz Syndrome
Authors: Shao Lei , Mardis Neil , Nopper Amy , Jarka Dale , Singh Vivekanand
Published: March 2013

Giant cell tumor of bone is a neoplasm that is rarely seen in children. Goltz syndrome is a disorder that affects multiple ectodermal and mesodermal tissues and has occasionally been associated with giant cell tumors of bone. Our case of giant cell tumor in a 5-year-old girl with Goltz syndrome suggests that this syndrome provides a unique situation wherein the practitioner should consider giant cell tumor of bone, even in a pediatric setting.
Comparison of overground and treadmill-based gaits of dogs
Authors: Torres Bryan T. , Moëns Noel M. M. , Al-Nadaf Sami , Reynolds Lisa R. , Fu Yang-Chieh , Budsberg Steven C.
Published: March 2013

Objective—To compare overground and treadmill-based gaits of dogs.

Animals —5 clinically normal adult mixed-breed dogs.

Procedures—To obtain dynamic gait data, 30 retroreflective markers were affixed bilaterally to specific regions of the hind limbs and pelvis of each dog. For each dog, 3-D joint motion data (sagittal [flexion and extension], transverse [internal and external rotation], and frontal [abduction and adduction] planes of motion) for the hip, femorotibial, and tarsal joints were acquired during walking and trotting through a calibrated testing space overground or on a treadmill. Comparison of data was performed via generalized indicator function analysis and Fourier analysis.

Results—Both overground and treadmill-based gaits produced similar waveforms in all planes of motion. Fourier analysis revealed no difference between overground and treadmill-based gaits in the sagittal plane of motion; however, small differences were detected between overground and treadmill-based gaits in the other 2 planes of motion. Additionally, femorotibial joint motion during walking did not differ among planes of motion. Generalized indicator function analysis was able to detect differences between overground and treadmill-based gait waveforms in all planes of motion for all joints during walking and trotting.

Conclusions and Clinical Relevance—In dogs, overground and treadmill-based gaits produced similar waveform shapes. Of the 3 planes of motion evaluated, only sagittal plane kinematic gait data were unaffected by mode of ambulation as determined via Fourier analysis. Sagittal kinematic gait data collected from dogs during overground or treadmill-based ambulation were comparable. However, analysis methods may affect data comparisons.
In vitro effects of lipid emulsion on platelet function and thromboelastography in canine blood samples
Authors: Tonkin Laura R. , Parnell Nolie K. , Hogan Daniel F.
Published: March 2013

Objective—To determine whether soybean oil emulsion has an in vitro effect on platelet aggregation and thromboelastography in blood samples obtained from healthy dogs.

Animals—12 healthy adult dogs.

Procedures—Blood samples were collected from each dog into tubes containing EDTA, hirudin, or sodium citrate for a CBC, collagen- and ADP-induced impedance aggregometry, or thromboelastography, respectively. Whole blood platelet aggregation, determined with ADP or collagen agonists, was measured in blood samples containing hirudin and final lipid concentrations of 0, 1, 10, and 30 mg/mL. The thromboelastographic variables R (reaction time), K (clotting time), α angle, and maximum amplitude were evaluated in blood samples containing sodium citrate and final lipid concentrations equivalent to those used for assessment of platelet aggregation.

Results—Median maximum ADP- and collagen-induced platelet aggregation in blood samples containing 1, 10, or 30 mg of lipid/mL did not differ significantly from the value for the respective lipid-free blood sample. Maximum amplitude determined via thromboelastography was significantly reduced in blood samples containing 10 and 30 mg of lipid/mL, compared with findings for lipid-free blood samples. Values of other thromboelastographic variables did not differ, regardless of lipid concentrations.

Conclusions and Clinical Relevance—Maximum amplitude determined via thromboelastography in canine blood samples was significantly affected by the addition of lipid to final concentrations that are several orders of magnitude higher than clinically relevant lipid concentrations in dogs. Lipid treatment appears to have no significant effect on hemostatic variables in dogs, although clinical studies should be performed to confirm these in vitro findings.
In vivo and in vitro effects of neostigmine on gastrointestinal tract motility of horses
Authors: Nieto Jorge E. , Morales Betina , Yamout Sawsan Z. , Stanley Scott D. , Harmon Faye A. , Snyder Jack R.
Published: March 2013

Objective—To determine the response to neostigmine of the contractile activity of the jejunum and pelvic flexure and the effects of a continuous rate infusion (CRI) of neostigmine in horses.

Animals—7 adult horses and tissue from 12 adult horses.

Procedures—A CRI of neostigmine (0.008 mg/kg/h) or placebo was administered to 6 horses in a crossover study design. Gastric emptying was evaluated by the acetaminophen test. The frequency of defecation and urination and the consistency and weight of feces were recorded throughout the experiment. The effect of neostigmine on smooth muscle contractile activity was evaluated in tissues from the jejunum and pelvic flexure. The effect of neostigmine and acetylcholine after incubation with muscarinic receptor antagonists (atropine and DAU 5884) and an acetylcholinesterase inhibitor (edrophonium) was also investigated in vitro.

Results—No difference was observed between neostigmine and placebo for time to reach peak plasma acetaminophen concentration and absorption rate constant. A CRI of neostigmine increased fecal production and frequency of urination. Neostigmine induced a dose-dependent increase of contractile amplitude in jejunum and pelvic flexure muscle strips. Incubation of muscle strips with atropine and DAU 5884 inhibited the response to acetylcholine and neostigmine. Incubation of smooth muscle strips from the jejunum with edrophonium increased the response to acetylcholine and had no effect on the response to neostigmine in vitro.

Conclusions and Clinical Relevance—A CRI of neostigmine increased fecal production and urination frequency in horses. A CRI of neostigmine did not decrease gastric emptying. Neostigmine stimulated contractile activity of jejunum and pelvic flexure smooth muscle strips in vitro.
Evaluation of plasma diazepam and nordiazepam concentrations following administration of diazepam intravenously or via suppository per rectum in dogs
Authors: Probst Curtis W. , Thomas William B. , Moyers Tamberlyn D. , Martin Tomas , Cox Sherry
Published: March 2013

Objective—To evaluate the pharmacokinetics of diazepam administered per rectum via compounded (ie, not commercially available) suppositories and determine whether a dose of 2 mg/kg in this formulation would result in plasma concentrations shown to be effective for control of status epilepticus or cluster seizures (ie, 150 to 300 ng/mL) in dogs within a clinically useful interval (10 to 15 minutes).

Animals—6 healthy mixed-breed dogs.

Procedures—Dogs were randomly assigned to 2 groups of 3 dogs each in a crossover-design study. Diazepam (2 mg/kg) was administered IV or via suppository per rectum, and blood samples were collected at predetermined time points. Following a 6- or 7-day washout period, each group received the alternate treatment. Plasma concentrations of diazepam and nordiazepam were analyzed via reversed phase high-performance liquid chromatography.

Results—Plasma concentrations of diazepam and nordiazepam exceeded the targeted range ≤ 3 minutes after IV administration in all dogs. After suppository administration, targeted concentrations of diazepam were not detected in any dogs, and targeted concentrations of nordiazepam were detected after 90 minutes (n = 2 dogs) or 120 minutes (3) or were not achieved (1).

Conclusions and Clinical Relevance—On the basis of these results, administration of 2 mg of diazepam/kg via the compounded suppositories used in the present study cannot be recommended for emergency treatment of seizures in dogs.
Assessment of cord dorsum potentials from caudal nerves in anesthetized clinically normal adult dogs without or during neuromuscular blockade
Authors: Campbell James O. , Olby Natasha J. , Hash Jonathan A. , Lascelles B. Duncan X.
Published: March 2013

Objective—To assess the feasibility of measuring cord dorsum potentials (CDPs) in anesthetized clinically normal dogs after caudal nerve stimulation, determine the intervertebral site of maximum amplitude and best waveform of the CDP, and evaluate the effects of neuromuscular blockade.

Animals—8 male and 4 female dogs (age, 1 to 5 years).

Procedures—Dogs were anesthetized, and CDPs were recorded via needles placed on the dorsal lamina at intervertebral spaces L1–2 through L7–S1. Caudal nerves were stimulated with monopolar electrodes inserted laterally to the level of the caudal vertebrae. Dogs were tested without and during neuromuscular blockade induced with atracurium besylate. The CDP latency and amplitude were determined from the largest amplitude tracings.

Results—CDPs were recorded in 11 of 12 dogs without neuromuscular blockade and in all dogs during neuromuscular blockade. The CDP was largest and most isolated at the L4–5 intervertebral space (3 dogs) or the L5–6 intervertebral space (9 dogs); this site corresponded to the segment of insertion of the first caudal nerve. Onset latencies ranged from 2.0 to 4.7 milliseconds, and there was no effect of neuromuscular blockade on latencies. Amplitudes of the CDPs were highly variable for both experimental conditions.

Conclusions and Clinical Relevance—CDPs were recorded from all dogs tested in the study; neuromuscular blockade was not critical for successful CDP recording but reduced muscle artifact. This technique may be useful as a tool to assess the caudal nerve roots in dogs suspected of having compressive lumbosacral disease or myelopathies affecting the lumbar intumescence.
Effect of acute exercise on monocarboxylate transporters 1 and 4 in untrained and trained Thoroughbreds
Authors: Kitaoka Yu , Endo Yukari , Mukai Kazutaka , Aida Hiroko , Hiraga Atsushi , Takemasa Tohru , Hatta Hideo
Published: March 2013

Objective—To evaluate the effects of a single incremental exercise test (IET) on mRNA expression and protein content of monocarboxylate transporter (MCT) 1 and MCT4 in the gluteus medius muscle of Thoroughbreds.

Animals—12 Thoroughbreds (6 males and 6 females; age, 3 to 4 years).

Procedures—Horses underwent an IET before and after 18 weeks of high-intensity exercise training (HIT). Horses were exercised at 90% of maximal oxygen consumption for 3 minutes during the initial 10 weeks of HIT and 110% of maximal oxygen consumption for 3 minutes during the last 8 weeks of HIT. Gluteus medius muscle biopsy specimens were obtained from horses before (baseline), immediately after, and at 3, 6, and 24 hours after the IET.

Results—Expression of MCT1 and MCT4 mRNA was upregulated at 3 and 6 hours after the IET in muscle specimens obtained from horses prior to HIT (untrained horses) and at 6 hours after the IET in muscle specimens obtained from horses after HIT (trained horses). For both untrained and trained horses, MCT1 and MCT4 protein contents were increased at 6 hours after the IET and did not differ at 24 hours after the IET, compared with those at baseline.

Conclusions and Clinical Relevance—Results indicated that a single IET resulted in transient increases in MCT1 and MCT4 mRNA expression and protein content in untrained and trained horses. These results may be important for the elucidation of exercise-induced alterations in lactate metabolism.
Study of Heat Absorption in Thermoforming for Transparent and Filled Polystyrene
Authors: Puehringer J. F. , Zitzenbacher G. , Spreitzer C.
Published: March 2013

Heating time and temperature distribution of a semi-finished pre-product are key factors for a satisfying final shape in the thermoforming process. The heating is in most cases done by radiation, which is modelled in simulation by the law of Bouguer Beer Lambert. Two material parameters, the reflection of the surface and the optical penetration depth are needed for the application of this law. One prerequisite for this is that the optical penetration depth is independent of the material thickness. In literature it is very often common to trust on that assumption and to determine it via single measurement of a film or plate with one thickness. The validity of this presumption is investigated for two different polystyrene compounds as part of this work. This assumption was fulfilled for a clear unfilled polystyrene (PS) in a wide range of wavelengths. In contradiction to this, the optical penetration depth of the white filled PS compound is dependent on film thickness. Moreover it increases slightly with film thickness. This deviation is correlated to the strong scattering effect of titanium dioxide contained in this compound.
Molecular Dynamics Study on Permeability of Gas Molecules through Amorphous PPX Polymers
Authors: Bian L. , Shu Y. , Xu J. , Wang L.
Published: March 2013

Amorphous poly-para-xylylene (PPX) polymers were constructed using molecular mechanics (MM) and NVT+NPT-annealing methods. They provide the cut-off free volumes to absorb and transfer gas molecules. The corresponding sorption and diffusion properties were determined via Grand Canonical Monte Carlo (GCMC), NVT-Molecular Dynamics (MD) and cluster analysis methods. The results showed that temperature and pressure influence the sorption properties of gases obviously, but not to the diffusion coefficients of gases. Analyzing on the mean square displacement (MSD) data, this work finds that gases walk randomly through amorphous PPX polymers. The relative cluster permeability approaches to the experimental data.
Melting Model for Starve Fed Single Screw Extrusion of Thermoplastics
Authors: Wilczyński K. , Nastaj A. , Wilczyński K. J.
Published: March 2013

Previous experimental studies of the polymer behavior in a starve fed single screw extrusion process have shown that contiguous solids melting mechanism which is observed for flood fed extrusion was not observed for starve fed extrusion. A new two-stage physical model of polymer melting in a starve fed single screw extrusion has been proposed with conductive mechanism for melting in the partially filled region and dispersed melting mechanism in the fully filled region. Mathematical models have been proposed for melting in both those regions. The models have been validated experimentally.
Radiosurgery for patients with unruptured intracranial arteriovenous malformations
Authors: Ding Dale , Yen Chun-Po , Xu Zhiyuan , Starke Robert M. , Sheehan Jason P.
Published: March 2013

Object

The appropriate management of unruptured intracranial arteriovenous malformations (AVMs) remains controversial. In the present study, the authors evaluate the radiographic and clinical outcomes of radiosurgery for a large cohort of patients with unruptured AVMs.

Methods

From a prospective database of 1204 cases of AVMs involving patients treated with radiosurgery at their institution, the authors identified 444 patients without evidence of rupture prior to radiosurgery. The patients' mean age was 36.9 years, and 50% were male. The mean AVM nidus volume was 4.2 cm3, 13.5% of the AVMs were in a deep location, and 44.4% were at least Spetzler-Martin Grade III. The median radiosurgical prescription dose was 20 Gy. Univariate and multivariate Cox regression analyses were used to determine risk factors associated with obliteration, postradiosurgery hemorrhage, radiation-induced changes, and postradiosurgery cyst formation. The mean duration of radiological and clinical follow-up was 76 months and 86 months, respectively.

Results

The cumulative AVM obliteration rate was 62%, and the postradiosurgery annual hemorrhage rate was 1.6%. Radiation-induced changes were symptomatic in 13.7% and permanent in 2.0% of patients. The statistically significant independent positive predictors of obliteration were no preradiosurgery embolization (p < 0.001), increased prescription dose (p < 0.001), single draining vein (p < 0.001), radiological presence of radiation-induced changes (p = 0.004), and lower Spetzler-Martin grade (p = 0.016). Increased volume and higher Pittsburgh radiosurgery-based AVM score were predictors of postradiosurgery hemorrhage in the univariate analysis only. Clinical deterioration occurred in 30 patients (6.8%), more commonly in patients with postradiosurgery hemorrhage (p = 0.018).

Conclusions

Radiosurgery afforded a reasonable chance of obliteration of unruptured AVMs with relatively low rates of clinical and radiological complications.
Debate on Pediatric Research
Authors: Lasker Shamima Parvin
Published: March 2013

DOI: http://dx.doi.org/10.3329/bioethics.v4i1.14262 Bangladesh Journal of Bioethics 2013; 4(1):1
Male Circumcision in India: Some Considerations from the West
Authors: Garasic Mirko Daniel
Published: March 2013

In this work, I will analyse why Indian authorities find it so difficult to publicly acknowledge the medical benefits of Male Circumcision (MC). In doing so, the medical evidence in favour of the practice, as well as the moral duties that governing authorities have towards their citizens shall be taken to the fore. In addition to this argument, a brief explanation of the cultural dimension that refuses to evaluate the medical dimension of MC a priori shall be taken into account and, in relation to that, a parallel with the past and present Western tradition will be drawn, putting forward the conclusion that both contexts do not provide satisfactory justification for banning MC nor more relevantly for the Indian scenario can any cultural background represent a convincing argument against the public acknowledgement of the medical advantages provided by MC. DOI: http://dx.doi.org/10.3329/bioethics.v4i1.14263 Bangladesh Journal of Bioethics 2013; 4(1):2-8