bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cellular Motility of Down Syndrome Gingival Fibroblasts Is Susceptible to Impairment by Porphyromonas gingivalis Invasion
Authors: Murakami Jumpei , Kato Takahiro , Kawai Shinji , Akiyama Shigehisa , Amano Atsuo , Morisaki Ichijiro 
Published: April 2008

Background: Severe periodontal breakdown is often associated with Down syndrome (DS); however, the etiology of this condition is not understood fully. Cellular motility of gingival fibroblasts is a critical event for wound healing and regeneration of periodontal tissues. Porphyromonas gingivalis is known to be a periodontal pathogen that invades host cells, contributing to periodontal destruction. In this study, we examined the influence of P. gingivalis infection on the motility of DS gingival fibroblasts (DGFs).Methods: DGFs and normal gingival fibroblasts (NGFs) were infected with P. gingivalis with type II fimbriae, and cellular motility was evaluated using an in vitro wounding assay. Protein degradation of α5β1‐integrin subunits and a migration‐regulating signaling molecule, paxillin, were investigated using specific antibodies. The adhesion to and invasion of fibroblasts by P. gingivalis were determined with a colony forming assay. The gene expressions of α5β1‐integrin subunits were also quantified using a reverse transcription‐polymerase chain reaction method.Results: The cellular motility of DGFs was impaired significantly by P. gingivalis compared to NGFs, and the former were invaded readily by P. gingivalis. Further, cellular paxillin from DGFs was degraded markedly by the pathogen. Although protein degradation of α5β1 integrin was induced, its mRNA expression was not affected significantly.Conclusions: P. gingivalis readily invades DGFs and subsequently degrades paxillin, which impairs cellular motility and likely prevents wound healing and the regeneration of periodontal tissues. These characteristics may be involved in the etiology of DS periodontitis.
Microbiologic and Immunologic Characteristics of Periodontal Disease in Hispanic Americans With Type 2 Diabetes
Authors: Ebersole Jeffrey L. , Holt Stanley C. , Hansard Richard , Novak M. John 
Published: April 2008

Background: The microbiology of periodontitis in type 1 diabetes has been reported, but less is known about type 2 diabetes. Moreover, these data have not linked microbial colonization, host response, and clinical presentation in type 1 or type 2 diabetes. The objectives of this study were to relate periodontal status, periodontal microorganisms, and host‐response characteristics in Hispanic Americans with type 2 diabetes.Methods: Plaque and serum samples were obtained from 63 Hispanic American subjects with and without type 2 diabetes. The microbiology of subgingival plaque samples was evaluated using DNA checkerboard hybridization, and serum antibody to a battery of oral microorganisms was determined using an enzyme‐linked immunosorbent assay.Results: In general, similar pathogens were present in periodontitis sites from subjects with and without type 2 diabetes, although the periodontitis sites in diabetes showed a higher frequency of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), and Campylobacter spp. Serum antibody to Campylobacter rectus was elevated in type 2 diabetes, whereas antibody to P. gingivalis and C. rectus were elevated in subjects with periodontitis, irrespective of diabetes status. Stratification of the population based upon antibody to P. gingivalis or C. rectus suggested a linkage between elevated antibody to P. gingivalis, increased frequency of diabetes, and significantly worse periodontitis.Conclusion: The increased severity of periodontal disease with type 2 diabetes may reflect an alteration of the pathogenic potential of periodontal bacteria and/or a modification of the characteristics of the host's inflammatory response that may contribute to a breakdown in the homeostasis of the periodontium.
Root Proximity as a Risk Factor for Progression of Alveolar Bone Loss: The Veterans Affairs Dental Longitudinal Study
Authors: Kim Taera , Miyamoto Takanari , Nunn Martha E. , Garcia Raul I. , Dietrich Thomas 
Published: April 2008

Background: The purpose of the present longitudinal study was to evaluate the association between root proximity and the risk for alveolar bone loss (ABL).Methods: We used data from the Veterans Affairs Dental Longitudinal Study, a closed‐panel longitudinal cohort study of 1,231 men enrolled in 1968 with triennial follow‐up examinations. Periapical radiographs of mandibular incisors from subjects with ≥10 years of follow‐up were selected. Interradicular distance (IRD) at the cemento‐enamel junction and alveolar bone levels at baseline and last follow‐up were measured using digitized radiographs. The rate of progressive ABL was determined and expressed as millimeters per 10 years. Site‐specific multivariate regression models were fit to evaluate the association between IRD and ABL rate, adjusting for age and smoking. Empirical standard errors and generalized estimating equations were used to account for the correlation among sites within subjects.Results: There were 473 dentate subjects, aged 28 to 71 years at baseline, with ≥10 years of follow‐up data available for analyses. The mean follow‐up time was 23 years. The mean IRD was 1.0 ± 0.3 mm, and the mean ABL rate during 10 years was 0.61 ± 0.59 mm. There was a significant non‐linear association between IRD and ABL rate (P <0.005). Compared to sites with IRD ≥0.8 mm, sites with IRD <0.6 mm were 28% (95% confidence interval [CI]: 11% to 48%) more likely to lose ≥0.5 mm of bone during 10 years (relative risk: 1.28 [95% CI: 1.11 to 1.48]) and 56% (95% CI: 11% to 117%) more likely to lose ≥1.0 mm of bone during 10 years (relative risk: 1.56 [95% CI: 1.11 to 2.17]).Conclusions: IRD <0.8 mm is a significant local risk factor for alveolar bone loss in mandibular anterior teeth. Measurement of IRD may have important prognostic value in making treatment decisions.
First Production Log Run in a Heavy-Oil Long-Horizontal Well Through a Y-Tool and Premium Screens
Authors: Montero Jacobo , Salazar Namir , Fondyga Tony , Reyes Kerwin 
Published: April 2008

Abstract
The first production log ever run in a heavy oil, long horizontal well completed with premium screens in open hole and through a Y-tool was successfully executed by Petroregional del Lago S. A. (a joint venture between PDVSA and Shell) in the Urdaneta West Field (Lake Maracaibo, Western Venezuela). The purpose of the job was to identify the origin of water in a well that experienced water break-through from the first day of production. A specialized set of logging tools was run to detect both water and oil flow, as well as to determine any flow behaviors like cross-flow that would help understand the source of water in the formation, obtain sufficient data to prepare a water shut-off program, and establish basic productivity information from the well, being this also the first production log run in the heavy oil wells in the field, which require artificial lift to flow. The results of the production log indicate that a sand package is producing water from an unexpected zone, which will require a water shut-off workover. This paper describes the planning, operational and interpretation processes of the logging activity, and presents a number of lessons learnt and useful recommendations for similar activities in heavy oil wells.
Effect of External Mechanical Damage on the Fatigue Life of Coiled Tubing Exposed to Sour Environments
Authors: Padron Tomas 
Published: April 2008

Abstract
In normal operations, coiled tubing (CT) is frequently subjected to mechanical damage on its outer surface that could adversely affect its fatigue life. The effect of transverse external mechanical damage, with depths in the range of 10% to 20% of the nominal wall thickness, on the fatigue life of grades 90 and 110 CT samples exposed to sour environments (i.e. solution NACE A saturated with 100% H2S) was reported in a previous paper (SPE 107113). The results showed that the fatigue life of the pipe was reduced significantly when the samples were pre-exposed to the sour environment used for these experiments. Additional testing was subsequently performed to asses less severe damage depths (i.e. &lt; 10%) and orientations (i.e. longitudinal), less severe environmental conditions (i.e. H2S concentrations lower than 100%), application of anti-cracking inhibitors, and the response of other CT grades (example: grade 100).
The present paper summarizes the results from the fatigue testing of more than 100 CT samples (grades 90, 100 and 110) with artificial mechanical damage in the transverse and longitudinal orientations, and depths from 5% to 20% of the nominal wall thickness, after being exposed to different sour environments (H2S concentrations from 1% to 100%) and including three different anti-cracking inhibitors.
A comparison between the sour fatigue life of the samples containing external mechanical damage and that of samples without damage is presented in terms of percentages of sweet life (i.e. fatigue life measured in air). Also, the effects of the damage depth and orientation, H2S concentration, and anti-cracking inhibitors on the fatigue life are analyzed. Finally, an inspection criterion for mechanical damage on strings to be used in sour environments is proposed.
A Field Study of Coiled-Tubing Material Loss and Ovality
Authors: Boles J. , Burgos R. , Medina A. 
Published: April 2008

Abstract
Coiled-Tubing (CT) integrity remains at the forefront in the mind of end users, particularly in high-end applications. The properties of a CT string, including ovality and wall thickness, change over time when it is run into and is pulled out of a well, due to a number of wear factors and a combination of them, including well trajectory, fluid properties, the CT properties and the applied external forces.
A typical CT string is exposed to a variety of applications during its lifetime, each having a different effect on the material. Ovality and wall thickness loss thus become critical telltale indicators for the condition of the pipe and its potential serviceability. Devices for ovality and wall thickness measurement, whether performed off-line or real time during a job, are readily available.
This paper demonstrates how one such device has been used for various services with CT, including acid stimulation work in Saudi Arabia, CTD work in Alaska, Nitrogen kick off, clean out and CT spooling in Columbia and extensive eLine operations in the Barnett Shale, Texas. These case studies will show the evolution of material loss and ovality and how the information can be used to monitor and maximize the life of the CT string in a way that no other technique or model is capable.
Through-Tubing Inflatable Technology Deployed on a Downhole Tractor System Provides Real-Time Cost Savings
Authors: Kelbie Graeme M. , MacKay John D. 
Published: April 2008

Abstract
Finding new ways to reduce the costs and production of unwanted water are of paramount importance to the upstream oil and gas industry. The continued discovery of marginal developments, the depletion of reserves from the more mature fields, and a worldwide increase in extended reach and horizontal drilling all provide new challenges on a daily basis. An economical and reliable method of performing zonal isolations and shutting off the unwanted water in these wells can be accomplished with through-tubing inflatable high-expansion devices. However, in the more extended reach and horizontal wells previously requiring coiled tubing or snubbing, there is a new alternative. To meet the reliability, time, and cost efficiency demands of the industries’ current fast pace environment, the downhole tractor system offers an effective new avenue for deployment of these isolation devices.
In this paper we will focus on a case history showing how the use of through-tubing inflatable technology run in conjunction with a downhole tractor system provides zonal isolation, and savings in time and cost in traditional rig and coiled tubing markets. The other added benefit that is so important is the reduced HSE risk from lighter lifts, reduced personnel and the fluid handling issues surrounded by the use of kill fluids is not needed because the operation is conducted without the need to kill the well.
Coiled-Tubing-Conveyed Proppant Treatment Yields Increase in Production Efficiency and Return on Investment
Authors: Peak Zeke T. , Montes Matthew B. , Natenberg David , Durkee Marc 
Published: April 2008

Abstract
Formation sand production and stimulation proppant flowback are large and costly production problems in maturing assets. Recently, a new coiled-tubing-conveyed proppant treatment (CTCPT) was applied for the operator in the Carr-Lundell field in Webb County, Texas. This technology effectively eliminated the production of formation solids and stimulation proppant. The result yielded increased efficiency in associated production time and decline rates, which have optimized return on investment. The new treatment has also reduced residual operational expenditures by eliminating costly workovers, equipment repair, and lost production caused by this escalating industry problem.
An Isolation and Remediation Solution for Wellhead Maintenance in the North Sea
Authors: Petrone Daniele , Rice Phillip , Pedersen Jørgen Hoj , Stjernholm Anders 
Published: April 2008

Abstract
Internal corrosion is prevalent in offshore wellheads in the Siri field in the Danish North Sea. Certain wellhead components must be replaced with corrosion-resistant parts. During the wellhead maintenance work, local regulations require a dual barrier and each of these barriers must be tested independently. The casing below the wellhead is completed with fiberglass lining. Standard bridge plugs and standard cleaning methods of tubing are incompatible with the lining and are not considered feasible.
This paper presents an alternative solution that uses two inflatable bridge plugs as an isolation method and provides the ability to remove the scale present in the well in the setting area. It details yard tests performed to ensure the chosen technique does not damage the lining of the tubing and can efficiently isolate the wellhead. It also reviews results of several operations performed between 2006 and 2007, in which inflatable bridge plugs were successfully set and retrieved in the fiberglass-lined tubing.
The Operational and Economical Impact of CT Spoolable Connectors During the Last Five Years in the Norwegian and Danish Sector of the North Sea: Case Histories
Authors: Sach M. , Maribu K. , Haga J. , Nesvik K. T. , Boye-Moller C. 
Published: April 2008

Abstract
Coiled Tubing (CT) equipment in the Norwegian sector of the North Sea has traditionally been heavy, due to CT reels using larger sizes of CT – a trend also observed in other areas. Due to the requirement of performing well interventions in longer wells and larger completion sizes, CT drums weighing 40-60 t have been utilised. Not many platform cranes are capable of lifting such heavy CT drums and during bad weather periods operations are often delayed, even when using significantly lighter CT drums. Using spoolable CT connectors allow for a long and heavy CT string to be lifted on board of a platform on two or more separate drums and joining them together again once onboard. More than 50% weight reduction has been achieved making operational schedules more predictable. In the geographical areas considered, spoolable CT connectors have outperformed traditional methods like boat spooling and butt-welding from a safety, operational and economical point of view.
Due to the reduction in weight, larger CT sizes have become available on older platforms as well. New CT applications that were previously considered unfeasible, like selective, high-rate acid fracing through CT, have been performed, extending the capabilities of CT interventions beyond previous logistical and technical limits. Being able to select the correct size of CT, with less dependency on offshore crane limits and weather has a fundamental impact on the usage of CT in the offshore industry.
Rather than discussing the spoolable CT connector itself, the primary intention of the paper is to re-view case histories that were performed during the last 5 years. Operational challenges that have been mastered, successes, failures and further developments are presented. A new CT reel configuration to simplify spoolable CT connector installation will be presented. The new applications made possible by this technology and their economic impact on the Norwegian CT market since year 2003 will be reviewed.
Flow Properties and Drag-Reduction Characteristics of Surfactant-Based Fluids (SBF) in Large-Scale Coiled Tubing
Authors: Kamel A. H. Ahmed , Shah S. N. 
Published: April 2008

Abstract
In spite of their wide use as friction reducer or fracturing fluid due to their unique characteristics, there is a very little information available in the literature about surfactant based fluids. Majority of this information is related to straight tubing with small sizes. Data of larger sizes as well as coiled tubing are very scarce. Furthermore, previous studies have correlated drag reduction behavior of these fluids only through simple power-law parameters. Little is known regarding the importance of elasticity on drag reduction of SBF. Scale-up factor is yet another problem.
This study aims at understanding the viscoelastic behavior of SBF and its effect on drag reduction in large-scale CT. The properties of widely used Aromox APA-T, a highly-active surfactant used as gelling agent in aqueous and brine base fluids, are investigated. Rheological and viscoelastic measurements are conducted for concentrations 1.5, 2, 3, and 4% vol. using Bohlin rheometer. Flow tests are conducted using ½- and 1½-in. CT with various curvature ratios. This study is the first investigation of flow behavior of SBF in a large-scale CT.
The results show that SBF exhibit a non-Newtonian pseudo-plastic behavior. Formation of rod-like micelles (emergence of viscoelasticity) is found to be affected by surfactant concentration and shear exerted on the fluid, which in turn, affects drag reduction characteristics. Also, simple correlations using only rheological properties may lead to erroneous results, especially when scaled-up to a large-scale.
Stimulation With Coiled Tubing and Fluidic Oscillation
Authors: Ulloa Gutiérrez Joel Vladimir , Callarotti Gian Franco , Akrich Oscar , Monroy Rafael Rodríguez 
Published: April 2008

Abstract
To enhance stimulation treatment placement and effectiveness in highly deviated and deep wells, a coiled-tubing intervention was designed and implemented using a fluidic oscillator. The stimulation treatments were developed to mitigate damage caused by fines migration, water blockage, scale, and asphaltenes; such damage is typically located in the near-wellbore area.
Traditionally in southern Mexico, stimulation treatments in highly deviated and deep wells were bullheaded from the surface using diversion techniques. Results from these treatments were not always satisfactory.
A fluidic oscillator was used as a placement technique for these stimulations. This tool, with no moving parts, generates a change in fluid direction that creates a low-amplitude pressure pulse at a frequency range from 300 to 600 Hz.
The synergy from the use of coiled tubing, a fluidic oscillator, and a tailored stimulation treatment was proven effective in stimulating these wells, achieving excellent results.
Case histories from four wells are presented: Samaria 1129, Iride 154, Jujo 654, and Mora 3.
Coiled Tubing and Nitrogen Generation Unit Operations: Corrosion Challenges and Solutions Found in Brazil Offshore Operations
Authors: Duque Luis H. , Guimarães Zacarias , Berry Sandra L. , Gouveia Manoel 
Published: April 2008

Abstract
For several years, coiled tubing offshore operations in Brazil have involved the use of nitrogen generation units. Remote locations, lack of liquid nitrogen suppliers and logistical issues, among others, have driven the main oil operator to increase the use of Nitrogen Generation Units.
Using a Nitrogen Generation Unit in remote locations, where most of the platforms have very limited space, was the ideal solution for a very old problem of supplying nitrogen. However, when the use of the Nitrogen Generation Unit was combined with coiled tubing operations, another concern arose.
In-situ nitrogen generation does not generate pure (99.9%) nitrogen gas. In-situ nitrogen generation can generate nitrogen gas compositions with oxygen contents as high as 5%. Nitrogen with oxygen contents as high as 5%, under downhole conditions of pressure and temperature, can result in severe corrosion problems in the coiled tubing string. Furthermore, together with the increased oxygen content, fluid systems such as completion brines and acids were pumped, which also increased the severity of the corrosive environment. Sometimes operations were stopped because the coiled tubing Bottom Hole Assembly (BHA) was completely plugged by oxidized/corroded metal solid flakes or the coiled tubing string became so corroded that it required inspection before further use in job operations. Based on these corrosion and safety issues the use of in-situ nitrogen generation loses its benefits.
To find a solution to this corrosion problem, a laboratory research study was performed with the most commonly used coiled tubing string material and the pumped treatment fluids under surface and downhole conditions with the maximum percentage of oxygen concentration that could be expected in operations. Several corrosion inhibitors and mixtures were tested for their ability to control the corrosion of the coiled tubing string.
After laboratory testing established which inhibitor systems would control the corrosion rate of the coiled tubing, yard tests were performed to confirm that the inhibitor would work in the field. After the field trial was performed successfully with several applications, the recommended practices were adopted from this research to avoid the corrosion problem faced in the past with the use of offshore nitrogen generation units.
This paper presents the sequence of events of this project: the coiled tubing corrosion observed in the laboratory research studies, the performed yard trials; the recommended field applications, as well as the benefits that this study and final application brought to the operations.
New Hydrajet Tool Demonstrates Improved Life for Perforating and Fracturing Applications
Authors: Surjaatmadja Jim B. , Bezanson Jeff , Lindsay Sharlene , Ventosilla Pedro , Rispler Keith 
Published: April 2008

Abstract
Hydrajet perforating and fracturing has recently gained popularity in the oilfield industry, especially when used with coiled tubing (CT). With coiled tubing, the task of placing many cuts at multiple places becomes straightforward and no longer time consuming. However, hydrajetting equipment life has been plagued with rapid failures, resulting in the need for time-consuming and costly tripping out and in the hole for jetting tool replacement.
To reduce or eliminate such tripping costs, substantial improvements of the hydrajetting tools are required. A mere change of materials or a redesign using concepts that follow the customary models has resulted in insignificant performance improvements. It was therefore decided that a complete overhaul of the design concepts needed to be made. By doing this, substantial improvements can be obtained.
This paper discusses unique improvements that have been made to the hydrajetting tools. The new tools address the aspects that have contributed to failures in the past. By taking a fresh perspective of this situation, a performance improvement of 200–300% can be attained. Recent perforating and stimulation experiences in the field demonstrate this and are discussed.