bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorylation of collapsin response mediator protein-2 disrupts neuronal maturation in a model of adult neurogenesis: Implications for neurodegenerative disorders
Authors: Crews Leslie , Ruf Rebecca , Patrick Christina , Dumaop Wilmar , Trejo-Morales Margarita , Achim Cristian L , Rockenstein Edward , Masliah Eliezer 
Published: September 2011

Abstract

Background
Recent studies suggest that the pathogenic process in neurodegenerative disorders may disrupt mature neuronal circuitries and neurogenesis in the adult brain. Abnormal activation of CDK5 is associated with neurodegenerative disorders, and recently a critical role for CDK5 in adult neurogenesis has been identified. We have developed an in vitro model of abnormal CDK5 activation during adult hippocampal neurogenesis, and here we used this model to investigate aberrantly phosphorylated downstream targets of CDK5.

Results
Abnormal CDK5 activation in an in vitro model of adult neurogenesis results in hyperphosphorylation of collapsin-response mediator protein-2 (CRMP2) and impaired neurite outgrowth. Inhibition of CDK5, or expression of a non-phosphorylatable (S522A) CRMP2 construct reduced CRMP2 hyperphosphorylation, and reversed neurite outgrowth deficits. CRMP2 plays a role in microtubule dynamics; therefore we examined the integrity of microtubules in this model using biochemical and electron microscopy techniques. We found that microtubule organization was disrupted under conditions of CDK5 activation. Finally, to study the relevance of these findings to neurogenesis in neurodegenerative conditions associated with HIV infection, we performed immunochemical analyses of the brains of patients with HIV and transgenic mice expressing HIV-gp120 protein. CDK5-mediated CRMP2 phosphorylation was significantly increased in the hippocampus of patients with HIV encephalitis and in gp120 transgenic mice, and this effect was rescued by genetic down-modulation of CDK5 in the mouse model.

Conclusions
These results reveal a functional mechanism involving microtubule destabilization through which abnormal CDK5 activation and CRMP2 hyperphosphorylation might contribute to defective neurogenesis in neurodegenerative disorders such as HIV encephalitis.
Case management of chiropractic patients with cervical brachialgia: A survey of French chiropractors
Authors: Guenoun Olivier , Debarle Michel , Garnesson Coralie , Proisl Sylvie , Ray Delphine , Leboeuf-Yde Charlotte 
Published: September 2011

Abstract

Background
Not much is known about the French chiropractic profession on, for example, level of consensus on clinical issues.

Objectives
The first objective was to investigate if French chiropractors' management choices appeared reasonable for various neck problem scenarios. The second objective was to investigate if there was agreement between chiropractors on the patient management. The third objective was to see to which degree and at what stages chiropractors would consider to interact with other health-care practitioners, such as physiotherapists, general practitioners and specialists.

Method
A questionnaire was sent to a randomly selected sample of all French chiropractors known to the national chiropractic college. It consisted of an invitation to participate in the study, a brief case description, and drawings of five stages of how a case of neck pain gradually evolves into a brachialgia to end up with a compromised spinal cord. Each stage offered five management choices. Participants were asked at what stages patients would be treated solely by the chiropractor and when patients would be referred out for second opinion or other care without chiropractic treatment, plus an open ended option, resulting in a "five-by-six" table. The percentages of respondents choosing the different management strategies were identified for the different scenarios and the 95% confidence intervals were calculated. There was a pre hoc agreement on when chiropractic care would or would not be suitable. Consensus was arbitrarily defined as "moderate" when 50- 69% of respondents agreed on the same management choice and as "excellent" when 70% or more provided the same answer. It was expected that inter professional contacts would be rare.

Results
The response rate was 53% out of 254 potential participants. The first two uncomplicated cases would generally have been treated by the chiropractors. As the patient worsened, the responses tended towards external assistance and for the most severe case, the majority of respondents would have referred the patient out. There was excellent consensus for the two extreme cases (the most benign and the most severe), moderate consensus for the cases next to these two and least agreement relating to the "middle" case. Inter-professional collaboration was contemplated mainly for the severe case.

Conclusion
The French chiropractors who participated in this study seem to have a similar approach to patients with neck pain that gradually develops into a brachialgia and worsens. However, it is not known if the large group of non-participants in the study would agree with this treatment strategy.
Will Imatinib Compromise Reproductive Capacity?
Authors: Zamah Alberuni M. , Mauro Michael J. , Druker Brian J. , Oktay Kutluk , Egorin Merrill J. , Cedars Marcelle I. , Rosen Mitchell P. 
Published: September 2011

Abstract
Imatinib mesylate is the first in a family of highly effective, minimally toxic, targeted agents used widely to treat Philadelphia-positive leukemias and selected other cancers, leading to a steady rise in the prevalence of patients using such therapy. Because failure of therapy would require conventional gonadotoxic chemotherapeutics, many female patients using imatinib may choose to preserve fertility. Herein, we provide evidence of a potential negative effect of imatinib on ovarian function by reporting the first case of a woman who showed a severely compromised ovarian response to gonadotropin stimulation while on imatinib, with a normal ovarian response after stopping this medication.
Reaction of GLDA with Calcite: Reaction Kinetics and Transport Study
Authors: Rabie Ahmed I. , Mahmoud Mohamed A. , Nasr-El-Din Hisham A. 
Published: September 2011

Abstract
Chelating agents have been used in the oil industry as iron control agents and scale removers, and recently as effective stand-alone stimulating fluids in matrix acidizing, especially for deep wells where using hydrochloric acid is restricted due its corrosion problems. The ultimate goal from using chelating agents is to create highly conductive wormholes that connect the formation to the wellbore. Glutamic acid diacetic acid (GLDA) is a new chelating agent that can be used for this purpose. The objective of this work is to study the reaction of GLDA with calcite and investigate the effectiveness of the created wormholes by both kinetics and transport studies that have been performed experimentally in the laboratory.
The reaction of GLDA with calcite was investigated by measuring the rate of dissolution using the rotating disk apparatus. The effect of initial pH (1.7, 3.8, and 13) and disk rotational speed (100-1800 rpm) on the rate of reaction was studied at 150, 220 and 300°F. Pink Desert limestone cores 1.5 in. diameter and 0.65 in. length were utilized. GLDA transport and its effect on wormhole creation were investigated in core flood experiments using samples of 1.5 in. diameter and 6 in. length. The cores were scanned using CT-scan before and after the injection of GLDA solutions into the cores. Core flood experiments were conducted at temperatures of 200 and 300°F.
The calcite dissolution rate was found to be a strong function of temperature and increased significantly by increasing the temperature from 80 to 300°F. Increasing the pH from 1.7 to 13 resulted in a reduction in the rate of dissolution. GLDA reacted with calcite by one of two mechanisms; hydrogen ion attack and calcium complexation reaction. The GLDA chelation ability (expressed as a percentage of the total rate of dissolution) decreased by increasing temperature, but was not affected much by changing the disk rotational speed.
Acid diffusivity was determined at pH 1.7, 3.8, and 13 and the data was used with core flood results to determine the Damköhler number. An optimal Damköhler number was found in all experiments that corresponds to a minimum pore volume required to breakthrough the cores. Increasing temperature or reducing the pH increased the optimum Damköhler number with a reduction in the minimum pore volume required to breakthrough.
Case Histories: Overcoming Lost Circulation During Drilling and Primary Cementing Operations Using an Environmentally Preferred System
Authors: Metcalf Arthur S. , Nix Kenneth , Martinez-Guedry John 
Published: September 2011

Abstract
Partial or total lost circulation is prevalent in the Permian Basin of West Texas during many drilling and cementing operations. Whether losses are due to highly vugular or cavernous intervals or due to low fracture gradients, the problem occurs over the entire region. The common practices for fighting these losses are foamed mud sweeps, foamed cements, lost circulation pills and high-viscosity gel spacers containing lost circulation materials.
This paper presents case histories representing more than 100 wells in which a new environmentally preferred system has been employed. Specifically, instances during drilling are discussed where partial to total losses in returns have occurred and have been restored by pumping 40 to 50 bbls of this new material. These same wells after restoring circulation resume drilling to total depth without any further losses. In addition, cases are presented where the system is used as a spacer pumped ahead of cement, resulting in the circulation of cement in an area where this has not occurred before. Another example resulted in the improvement of bonding by the cement. Additional scenarios demonstrate that pumping this material on a single stage cementing job, could replace the normal two stage job.
Enhancing Production by Removing Zinc Sulfide Scale From an Offshore Well: A Case History
Authors: Berry Sandra L. , Boles Joel L. , Singh Amit , Hashim Imran 
Published: September 2011

Abstract
Deposition of mineral scales is the root cause of many production problems in oil and gas operations. These scale deposits have resulted in formation damage, production losses, significant rate and pressure reductions, and equipment failure due to corrosion issues. The most commonly encountered mineral scales in the oilfield are carbonates and sulfate-based calcium sulfate, barium sulfate, and strontium sulfate scales. However, a more unusual form of these mineral scales— zinc sulfide—has recently been reported.
This paper focuses on the systematic study of a zinc sulfide scale and the operation that removed it from a well in the Gulf of Mexico. Identifying the scale form and composition, and the factors affecting its dissolution resulted in a treatment that successfully removed the scale, thereby enhancing gas production from the well.
This scale was identified as wurtzite, a form of zinc sulfide scale. Extensive laboratory testing considered acid solubility and other scale-removal issues at downhole temperature and pressure conditions, as compared to the theoretical solubility of zinc sulfide in HCl acid. The study also determined that other factors may affect the real-world dissolution efficiency of the acid: pressure changes, hydrogen sulfide scavenger concentration and type, the ratio of acid volume to scale weight, pre-treatment oxidizer use, and pH values that prevent re-precipitation of dissolved scale.
The paper will describe the pre-job testing process and a field case history of a coiled tubing acid scale treatment that effectively removed the zinc sulfide scale from tubulars and the formation. Data will be presented showing the composition of the acid-flowback samples as well as the treatment and production charts.
Evaluation of New Drilling Approach for Widening Operational Window: Implications for Wellbore Strengthening
Authors: Salehi S. , Nygaard R. 
Published: September 2011

Abstract
The window between pore pressure and fracture gradient is usually the most critical factor in well design. The width of this window dictates well control and loss circulation prevention. Most notably, in deep offshore basins this window becomes narrower which makes it more challenging to control the ECD. Similar scenario happens in highly deviated and/or horizontal borehole in which fracture gradient significantly decrease as deviation angle increases.
To mitigate the small tolerance between pore pressure and fracture gradients an engineering practice referred to as "wellbore strengthening" is conducted to increase the fracture gradient. The method relies on propping and/or sealing the fractures with specially designed materials. Different competing theories exist for wellbore strengthening mechanisms. These can be categorized into two groups. The first group believes that strengthening happens as a result of increasing wellbore hoop stress when a wedge inserted into the fracture while the second group emphasis on fracture tip isolation with suitable materials and enhancing fracture propagation pressure. The existing numerical models and lab experiments done so far did not fully replicate the same operational phenomenon to understand the true mechanism.
The main objective of this study was to compare the existing wellbore strengthening models using both numerical simulations and analytical solution for different field cases. Results of finite-element analysis for fracture initiation, propagation, sealing and stress changes after each step are provided. Our numerical results indicate that wellbore hoop stress cannot be higher than its ideal case in the fractured zone by plugging and/or sealing fractures. However, strengthening the wellbore and increasing the fracture gradient can be done by enhancing fracture propagation pressure.
Development of Water-Based Drilling Fluids Customized for Shale Reservoirs
Authors: Deville Jay P. , Fritz Brady , Jarrett Michael 
Published: September 2011

Abstract
Drilling activity has increased dramatically in unconventional shale gas reservoirs. The drilling fluid of choice in these shale plays is often non-aqueous based fluid (NAF). While NAFs can provide advantages such as shale stabilization, lubricity, and contamination tolerance, environmental consequences and associated costs are an issue. These disadvantages cause operators to seek water-based muds (WBM) for drilling many of these gas reservoirs.
Despite some operational similarities, a wide variety of unique downhole conditions can be found in the shale plays. Shale mineralogy and bottomhole temperature represent just two highly variable critical factors in unconventional gas reservoirs. Therefore, a single water-based solution for addressing shale plays globally is not a realistic option. Instead, a customized approach that delivers water-based muds formulated specifically for a given shale play has been pursued.
Customization relies on detailed analysis of the well parameters of a given shale play. This analysis includes not only the shale morphology and lithology, but also well drilling program plans, environmental factors and other reservoir-specific considerations. Applying appropriate drilling fluid chemistries based on this detailed analysis has led to the successful field deployment of a number of new shale fluids.
Details of the process utilized for customizing a WBM for a shale play, as well as specific examples of new fluids developed for the Barnett, Fayetteville, and Haynesville shales are presented in this paper. Full laboratory development and testing is described. Additionally, field trial results are presented that show specially-designed WBMs can provide comparable performance to NAFs, but with enhanced environmental and economic benefits. Application of the customization process to develop WBMs for other shale plays around the globe is also discussed.
Development of a Continuous Directional Coring System for Deep-sea Drilling
Authors: Shinmoto Y. , Miyazaki E. , Wada K. , Yamao M. 
Published: September 2011

Abstract
Core sampling is one of most important methods to gain knowledge on formation properties below the sea-floor or to extract such potential new energy resources as methane hydrates. The riser-equipped deep-sea drilling vessel Chikyu carries out scientific expeditions for such underwater formation core drilling and to analyze the origin of hydrate generation around the coast of Japan. Among the various systems available, continuous coring using wireline is the most promising in obtaining a steady supply of core samples.
Although MWD/LWD methods are deployed, an advanced directional control system specifically for deep-sea coring is presently under technical development. Core barrels consisting of the inner and outer barrels have been designed with an inner barrel that is retrievable and resettable. The new method combines an adjustable bent housing sub which is located between the outer barrel and just above the inner core tube.
Laboratory tests in which the inner barrel is passed through the bent housing section have been carried out with results showing bent housing angles of 0.25 ∼ 2.0 degrees. Land drilling tests with the bent housing were also carried out in order to ensure drilling efficiency and core recovery. This paper presents the progress of our newly developed coring system with an integrated analysis of directional drilling and coring capabilities.
Bridging the Gap between Laboratory Characterization and Field Applications of Friction Reducers
Authors: Zhou Jia , Sun Hong , Stevens Richard , Qu Qi , Bai Baojun 
Published: September 2011

Abstract
Slickwater fracturing technology has been widely and successfully used for well stimulation because it is inexpensive and causes relatively little formation damage. Friction reducers are always employed in the slickwater fracturing fluid system due to the high friction pressures resulting from the high rates of fluid injection. Polyacrylamide-based polymer is the most common friction reducer in the industry. Many papers have reported the results of tests on friction reducers in water-based fluids in laboratory-scale straight and coiled tube, but few have attempted to address the gap between laboratory and field operation data. For example, laboratory tests using conventional fluid rheological parameters do not accurately predict friction reduction when applied to the large pipes used in field operations. Friction reducer evaluation using full-scale flow loop testing with tube sizes comparable to those used in field operations are typically expensive and require large volumes of fluids, making them impractical. This paper describes an attempt to address the gap between laboratory characterizations and field operations. It reports a study of two common friction reducers studied in a laboratory setup and compares the results with the recorded data from a large number of slickwater fracturing treatments over a wide range of pumping rates and well tube sizes. It introduces a new concept of effective pipe diameter, which, correlated with a fluid velocity profile, permits development of a model to reliably predict field friction reduction from laboratory results. The correlation between laboratory and field data is validated by comparing predictions with actual field data. The study demonstrates that correct lab testing parameters are essential for reliably using laboratory results to predict the effectiveness and performance of friction reducers under field conditions.
Field Study of the Physical and Chemical Factors Affecting Downhole Scale Deposition in the North Dakota Bakken Formation
Authors: Cenegy Lawrence M. , Mcafee Clyde A. , Kalfayan Leonard J. 
Published: September 2011

Abstract
North Dakota Bakken oil recovery has increased nearly 100 fold over the last five years, driven by technological advancements in hydraulic fracturing and completion design. For one North Dakota operator with 150 Bakken-producing wells, 22 of the wells have experienced at least one event of severe calcium carbonate scaling in the pump and production tubing, leading to well failure. Bakken wells are completed to a vertical depth of approximately 10,000 ft with horizontal laterals up to 10,000 ft and produced via multi-zone hydraulic fracturing.
The operator initially conducted a typical scale prediction study in order to reduce well failures and maintain oil production. However, the scale prediction study was challenging to perform for these Bakken wells due to the variability of the composition of the produced water. Attention then turned to the tracking and analysis of historic field conditions. A ‘post-mortem’ of data collected from all failed wells due to scale was conducted, considering the failure type, date, type of hydraulic fracturing procedure, pump intake pressure, scale inhibitor residual, calcium carbonate scaling index, geographic failure concentration, production time to failure, and cumulative water production to failure.
Results showed that 82 percent of the wells failed during early production (defined as less than 20,000 barrels of water produced and two years production since first oil), after which failures became increasingly rare. This correlated with transient alkalinity spikes in the water analyses attributed to fracturing fluid flowback during this critical period. Simulated blending of fracturing and formation waters demonstrated that this was the most important period to maintain high scale inhibitor residuals due to high deposition potentials.
This paper discusses the various field and laboratory studies conducted in an effort to understand the problem, results obtained and implications. Also discussed is the evaluation of two scale inhibitors before and after laboratory aging in simulated fracturing fluids.