bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coal Bed Gas Productivity Prediction By Stoneley Wave Analysis
Authors: Dey Swapan Kumar 
Published: January 2010

AbstractCoal is an organic sedimentary rock which acts like a dual porosity reservoir where the vast majority of gas is stored in the low porosity coal matrix (primary porosity) by adsorption. But the production of coal bed methane occurs through the natural fracture systems (cleats) of the coal (secondary porosity) because coal matrix has virtually nil permeability. Hence the determination of petrophysical characteristics of fracture system in coal beds and the properties of the fluid present in the cleat systems are the key parameters that ultimately determines the deliverability of a CBM reservoir. Laboratory and field test have shown that under some conditions the dynamic stresses imposed on an interconnected fracture by a propagating wave can produce fluid motions, the magnitude of which is a function of fracture permeability. The energy used in producing the fluid motion in turn affects the wave propagation. Different studies were carried out by A. Norris (1989) and Tang et al. (1991) on the interaction of Stoneley waves with fractures intersecting a borehole has related the attenuation characteristics of Stoneley waves to the permeability of interconnected fracture and the properties of the fluid present in it. The physics of the interaction of Stoneley wave with fracture and fracture fluid is well understood in principle but the complexity of cleat geometry and lithological composition of different types of coal imposes the need of simplifying the theory so as to make it applicable for analysis of field data. The detailed study of the Stoneley wave attenuation characteristics observed in complete acoustic waveform in CBM wells acquired by sonic imaging tools and subsequent processing of the data along with other logs has helped in prediction of the gas producilbility of the coal beds, thus making it a key productivity indicator of CBM reservoir.
Well Integrity Issues in Malacca Strait Contract Area
Authors: Calosa Weka Janitra , Sadarta Bambang , Ronaldi Ronaldi 
Published: January 2010

Summary
The Malacca Straits contract area is located on the east of Sumatera Island between Sumatera and the Malaya Cape. This area started oil production in the early 1980’s, and consist of 175 onshore and offshore oil wells spread over five fields, namely the Kurau, Melibur, Selatan, Lalang, and Mengkapan oil fields.
A 7.9 Richter scale earthquake occurred on 12 September 2007. The epicenter of the earthquake was 159 KM south west of Bengkulu, a province in the southern part of Sumatera. Two days later, during a snubbing unit service on the K-02 well, the 9-5/8" casing suddenly dropped down six feet. It was believed that the area had been impacted by the earthquake since another snubbing unit found lateral movement on wellhead while doing workover on nearby well. Following the incident, the well services team inspected the K-02 well and found it had an integrity problem.
This finding lead to a wider investigation, which revealed that other wells also suffered integrity problems, including unsecured wellheads, leaking wellheads and christmas trees, severe corrosion of well components, failure of cement bonding, and casing elongation / casing drop due to top soil compaction / reservoir subsidence. At this point, it was decided to initiate a comprehensive well integrity study.
The integrity problems are due to several causes: wells exceeding their design life (most wells were constructed in the mid to late nineteen-eighties), exploration wells being used as producers without improvement, environmental degradation from deforestation (drop in the water table causing top soil compaction), and more than twenty years of production (causing formation subsidence).
This paper details the well integrity study, including the well assessment, the evaluation of well operation in term of safety, environment and profitability, and recommended effective temporary remedial actions.
System Approach to Horizontal Well Completion in the Vankor Field
Authors: Semenov A. A. , Malyasov V. J. , Nukhaev M. T. 
Published: January 2010

Abstract
The Vankor oil field is one of the largest oil fields in the world that was put into production recently. Main reserves are situated in the two thin productive layers. Each of them has active aquifer and huge gas cap. Wells with horizontal section of 1 km are used. Due to high reservoir heterogeneity and variation in permeability, inflow to the horizontal well is not uniform. As a consequence, recoverable reserves are various in different parts of the same well. Development of the approach to selection the best well completion system, its implementation and control were main purposes of this investigation.
The first stage of this investigation includes preliminary estimation of appropriate well completions before field development starts. An NPV criterion is used for comparison. Very limited field data were available on this step. An approximate model and special decision-making procedures were used. According to this estimation the use of ICD in some wells helps in managing inflow profile efficiently.
One of the main issues consists in a forecast of flow profile to a horizontal well. In this research we used LWD data as a source of online information about rock properties distribution in the horizontal section. PLT data were used to select an appropriate inflow model. On this stage, an approximate model was developed and validated using surface measurements of multiphase flow, horizontal part flow and pressure distribution. This model includes reservoir, ICD, horizontal section, inclined wellbore and surface choke.
Last, a design of a completion system (the sand screen with ICD) was made. Different cases were compared using the sector hydrodynamic model. Oil, water and gas flow profiles in the horizontal part at different times were used to select a choke level and swellable packer's positions. So the optimal completion design in terms of cumulative oil, water and gas production from well was selected and installed in the number of the Vankor wells.
In short this paper presents new system approach to the selection of a completion system. Appropriate numerical models (approximate, sector hydrodynamic) are used on each step depending on the available information and its confidence level. This method is used in some typical wells of the Vankor field.
Managing Oil Spill Risks of Transnational Onshore Pipelines
Authors: Guevarra Joselito 
Published: January 2010

Abstract
The management of oil spill risks of large transnational onshore pipelines is a huge and demanding task but one that is not impossible as shown by the examples of the BTC and Trans-Alaskan pipelines. Their trans-boundary nature poses significant challenges in terms of positioning of the infrastructure, the supporting logistics and the deployment of resources to combat accidental oil spills. This paper looks at industry best practices and presents a methodology and framework for managing oil spill risks by distilling lessons from industry and using the experience of Oil Spill Responsein responding to inland oil spills from pipelines.
Recurrence of Type 1 Diabetes After Simultaneous Pancreas-Kidney Transplantation, Despite Immunosuppression, Is Associated With Autoantibodies and Pathogenic Autoreactive CD4 T-Cells
Authors: Vendrame Francesco , Pileggi Antonello , Laughlin Elsa , Allende Gloria , Martin-Pagola Ainhoa , Molano R. Damaris , Diamantopoulos Stavros , Standifer Nathan , Geubtner Kelly , Falk Ben A. , Ichii Hirohito , Takahashi Hidenori , Snowhite Isaac , Chen Zhibin , Mendez Armando , Chen Linda , Sageshima Junichiro , Ruiz Phillip , Ciancio Gaetano , Ricordi Camillo , Reijonen Helena , Nepom Gerald T. , Burke George W. , Pugliese Alberto 
Published: January 2010

OBJECTIVE
To investigate if recurrent autoimmunity explained hyperglycemia and C-peptide loss in three immunosuppressed simultaneous pancreas-kidney (SPK) transplant recipients.

RESEARCH DESIGN AND METHODS
We monitored autoantibodies and autoreactive T-cells (using tetramers) and performed biopsy. The function of autoreactive T-cells was studied with in vitro and in vivo assays.

RESULTS
Autoantibodies were present pretransplant and persisted on follow-up in one patient. They appeared years after transplantation but before the development of hyperglycemia in the remaining patients. Pancreas transplant biopsies were taken within ∼1 year from hyperglycemia recurrence and revealed β-cell loss and insulitis. We studied autoreactive T-cells from the time of biopsy and repeatedly demonstrated their presence on further follow-up, together with autoantibodies. Treatment with T-cell–directed therapies (thymoglobulin and daclizumab, all patients), alone or with the addition of B-cell–directed therapy (rituximab, two patients), nonspecifically depleted T-cells and was associated with C-peptide secretion for &gt;1 year. Autoreactive T-cells with the same autoantigen specificity and conserved T-cell receptor later reappeared with further C-peptide loss over the next 2 years. Purified autoreactive CD4 T-cells from two patients were cotransplanted with HLA-mismatched human islets into immunodeficient mice. Grafts showed β-cell loss in mice receiving autoreactive T-cells but not control T-cells.

CONCLUSIONS
We demonstrate the cardinal features of recurrent autoimmunity in three such patients, including the reappearance of CD4 T-cells capable of mediating β-cell destruction. Markers of autoimmunity can help diagnose this underappreciated cause of graft loss. Immune monitoring during therapy showed that autoimmunity was not resolved by the immunosuppressive agents used.
Recurrent Moderate Hypoglycemia Ameliorates Brain Damage and Cognitive Dysfunction Induced by Severe Hypoglycemia
Authors: Puente Erwin C. , Silverstein Julie , Bree Adam J. , Musikantow Daniel R. , Wozniak David F. , Maloney Susan , Daphna-Iken Dorit , Fisher Simon J. 
Published: January 2010

OBJECTIVE
Although intensive glycemic control achieved with insulin therapy increases the incidence of both moderate and severe hypoglycemia, clinical reports of cognitive impairment due to severe hypoglycemia have been highly variable. It was hypothesized that recurrent moderate hypoglycemia preconditions the brain and protects against damage caused by severe hypoglycemia.

RESEARCH DESIGN AND METHODS
Nine-week-old male Sprague-Dawley rats were subjected to either 3 consecutive days of recurrent moderate (25–40 mg/dl) hypoglycemia (RH) or saline injections. On the fourth day, rats were subjected to a hyperinsulinemic (0.2 units · kg−1 · min−1) severe hypoglycemic (∼11 mg/dl) clamp for 60 or 90 min. Neuronal damage was subsequently assessed by hematoxylin-eosin and Fluoro-Jade B staining. The functional significance of severe hypoglycemia–induced brain damage was evaluated by motor and cognitive testing.

RESULTS
Severe hypoglycemia induced brain damage and striking deficits in spatial learning and memory. Rats subjected to recurrent moderate hypoglycemia had 62–74% less brain cell death and were protected from most of these cognitive disturbances.

CONCLUSIONS
Antecedent recurrent moderate hypoglycemia preconditioned the brain and markedly limited both the extent of severe hypoglycemia–induced neuronal damage and associated cognitive impairment. In conclusion, changes brought about by recurrent moderate hypoglycemia can be viewed, paradoxically, as providing a beneficial adaptive response in that there is mitigation against severe hypoglycemia–induced brain damage and cognitive dysfunction.
Effect of Renin-Angiotensin System Blockade on Insulin Resistance and Inflammatory Parameters in Patients With Impaired Glucose Tolerance
Authors: Pscherer Stefan , Heemann Uwe , Frank Helga 
Published: January 2010

OBJECTIVE
The study investigated the effect of angiotensin receptor blockers (ARB) on glucose homeostasis and inflammatory parameters in patients with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS
We prospectively studied the insulin sensitivity index (ISI) and homeostasis model assessment–insulin resistance (HOMA-IR) in 13 obese males with IGT and in 13 matched control subjects with normal glucose tolerance (NGT) during hyperglycemic testing over 90 min. Adiponectin, retinol-binding protein 4 (RBP4), and high-sensitive C-reactive protein (hsCRP) were analyzed. Measurements were performed at baseline and after a 4-week treatment with 160 mg/day valsartan. The results of the IGT and NGT groups were compared.

RESULTS
At baseline, HOMA-IR (IGT 4.1 ± 3 vs. NGT 2.3 ± 1.0, P &lt; 0.01), hsCRP (IGT 3.9 ± 1.9 vs. NGT 1.8 ± 1 mg/l, P &lt; 0.05), and RBP4 (IGT 27.1 ± 2.1 vs. NGT 24.0 ± 2.0 ng/ml, P &lt; 0.05) were significantly higher, whereas ISI (IGT 1.5 ± 0.9 vs. NGT 1.8 ± 1.2, P &lt; 0.05) and plasma adiponectin (IGT 3.2 ± 0.9, NGT 5.2 ± 2.4 μg/ml, P &lt; 0.05) were significantly lower in the IGT group compared with the NGT group. Under ARB, there was an increase in both groups of adiponectin (IGT 4.1 ± 1.9 μg/ml, NGT 6.3 ± 2.9 μg/ml, P &lt; 0.05) and an increase in ISI (IGT 1.5 ± 0.9 to 2.3 ± 1 μg/ml, NGT 1.8 ± 1 to 2.5 ± 2 μg/ml, P &lt; 0.05). HOMA-IR (4.1 ± 3 to 2.6 ± 2; P &lt; 0.01), hsCRP (3.9 ± 1.9 to 1.8 ± 1 mg/l, P &lt; 0.05), and RBP4 (27.1 ± 2.1 to 22.1 ± 1.8 ng/ml, P &lt; 0.01) decreased significantly in the IGT group.

CONCLUSIONS
Insulin sensitivity and associated inflammatory factors improve under ARB in IGT patients.
Detection of breast cancer by soft-copy reading of digital mammograms: Comparison between a routine image-processing parameter and high-contrast parameters
Authors: Kamitani Takeshi , Yabuuchi Hidetake , Soeda Hiroyasu , Matsuo Yoshio , Okafuji Takashi , Sakai Shuji , Setoguchi Taro , Hatakenaka Masamitsu , Ishii Nobuhide , Honda Hiroshi 
Published: January 2010

Background: Recent studies have reported the clinical usefulness of the soft-copy reading of mammograms. However, image-processing parameters for soft-copy reading of digital mammograms have not been established. Purpose: To compare observer performance in detecting breast cancer by soft-copy reading of digital mammograms using a routine image-processing parameter versus each of several high-contrast parameters. Material and Methods: The mammograms of 154 breasts, including 48 abnormal breasts with breast cancer and 106 normal breasts, were examined. Cancers were classified into 34 mass-dominant cancers, 11 microcalcification-dominant cancers, two cancers showing only architectural distortion, and one cancer without abnormal findings. All mammograms were performed using a computed radiography (CR) system. Each image was processed using GA (1.2), which was the contrast parameter recommended by the manufacturer for hard-copy film, GA (1.4), GA (1.6), and GA (1.8). These images were displayed on 5-megapixel (M) liquid-crystal display monitors. Five experienced radiologists classified them into BI-RADS category 1–2 or 3–5, and were also asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of masses and microcalcifications in each breast. Results: In mass-dominant cancers of dense breast tissue, the mean sensitivities of GA (1.2), GA (1.4), GA (1.6), and GA (1.8) were 32.7, 38.2, 36.4, and 40.0, and the AZ values were 0.67, 0.73, 0.71, and 0.73, respectively; in microcalcification-dominant cancers, the mean sensitivities were 80.0, 74.5, 80.0, and 78.2, respectively; however, there were no significant differences among them. Conclusion: High-contrast parameters tended to show relatively high sensitivity and AZ values in the detection of masses in dense breast tissue, but relatively low sensitivity for microcalcifications.
Low-dose contrast-enhanced magnetic resonance imaging of brain metastases at 3.0t using high-relaxivity contrast agents
Authors: Huang Biao , Liang Chang-Hong , Liu Hong-Jun , Wang Guang-Yi , Zhang Shui-Xing 
Published: January 2010

Background: Lesion-to-brain contrast after gadolinium administration is significantly higher at 3.0 Tesla (T) compared to 1.5T. The high in vivo relaxivity of gadobenate dimeglumine (Gd-BOPTA) may permit the use of lower-dose contrast agents. Purpose: To investigate whether low-dose contrast-enhanced MRI at 3.0T using a high-relaxivity contrast agent (Gd-BOPTA) can achieve a comparable or improved contrast-to-noise ratio (CNR) for the detection of brain metastases compared with examination of the same patient at 1.5T using a standard dose of gadopentetate dimeglumine (Gd-DTPA). Material and Methods: A total of 18 patients with known brain metastases were first imaged at 1.5T with 0.1 mmol/kg Gd-DTPA. Patients returned at least 24 hours later for imaging at 3.0T with Gd-BOPTA at cumulative doses of 0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg, and 0.1 mmol/kg (0.1 mmol/kg body weight overall). The CNR of enhancing brain lesions compared to the normal contralateral white matter was calculated. For the 3.0T study using different cumulative doses of Gd-BOPTA, the CNR of lesions was compared with CNR of the same lesions imaged at 1.5T using 0.1 mmol/kg Gd-DTPA, by using the Wilcoxon matched-pairs signed-rank test. Results: At 1.5T with 0.1 mmol/kg Gd-DTPA, the mean CNR between enhanced lesions and cerebral white matter was 12.01 ± 2.53. With 3.0T imaging using different cumulative doses of Gd-BOPTA, the mean CNRs were 7.19 ± 4.06, 15.31 ± 6.37, 25.44 ± 11.02, and 31.88 ± 13.21. At 3.0T with 0.05 mmol/kg Gd-BOPTA, CNR was 1.34-fold higher compared to CNR at 1.5T with 0.1 mmol/kg Gd-DTPA ( P <0.01). Conclusion: Comparable contrast enhancement of brain metastases can be achieved with a 0.05-mmol/kg dose of Gd-BOPTA at 3.0T compared to imaging at 1.5T using 0.1 mmol/kg Gd-DTPA.
A pilot study to assess the feasibility of measurement of adrenal gland volume by magnetic resonance imaging
Authors: Grant Lee A. , Napolitano Antonella , Miller Sam , Stephens Kimberley , McHugh Simon M. , Dixon Adrian K. 
Published: January 2010

Background: Repeated computed tomography (CT) assessment of the adrenal glands is associated with a significant radiation burden. The increasing capabilities of magnetic resonance (MR) volumetric analysis of the adrenals make this a potentially alternative technique in man. Purpose: To determine whether MR imaging could be used to measure adrenal volume, and to determine the intra- and interobserver variation and repeatability of MR volume imaging of adrenals in healthy human subjects. Material and Methods: This was a single-cohort, sequential design, three-part study involving four MRI examinations per subject following ethical approval and informed consent. Information was collected on four healthy subjects (three male and one female). Two different investigators estimated the area of the adrenal gland for each of the 3-mm contiguous slices (and consequently adrenal volume). In order to estimate inter- and intrareader variability, a repeated-measures mixed model was fitted with adrenal volume as the dependent variable. In order to estimate any bias between readers, Bland-Altman methodology was applied. Results: Intraobserver variation for adrenal gland volume is approximately 5% of a 3-cm3 adrenal gland. Interobserver variation is approximately 9% of a 3-cm3 adrenal gland. Potential variation in measurement for adrenal volume from all sources equates to approximately 14% of a 3-cm3 adrenal gland. Verification of image reading by a second investigator (consensus reading) reduces variability. Conclusion: Analysis of adrenal gland volume using MRI is a potentially reliable technique that could be used to assess a pathological change in adrenal size.
High-contrast computed tomographic angiography better detects residual intracranial arteriovenous malformations in long-term follow-up after radiotherapy than 1.5-tesla time-of-flight magnetic resonance angiography
Authors: Giesel Frederik L. , Essig Marco , Zabel-Du-Bois Angelika , Bock Michael , Tengg-Kobligk Hendrik von , Afshar-Omarei Ali , Debus Jürgen , Kauczor Hans-Ulrich , Krix Martin 
Published: January 2010

Background: Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are noninvasive alternatives for therapy monitoring of cerebral arteriovenous malformation (AVM). Purpose: To evaluate if CTA is able to detect residual AVM in the long-term follow-up after radiotherapy when time-of-flight (TOF) MRA could no longer detect a remaining nidus. Material and Methods: 18 patients with intracranial AVM were included between November 2005 and August 2007 who were scheduled for CTA (16-slice CT, 1-mm slice thickness, 90 ml iomeprol 400 mg I/ml, 4 ml/s) in the follow-up of radiotherapy. In these patients, MRA (3D-TOF, and bolus tagging at 1.5T) could no longer detect a remaining nidus. Results: The previously performed MRA (median time between CTA and MRA, 2.5 months) described total obliterations in 14 and subtotal obliterations in two AVM cases. Two MRA diagnoses were inconclusive due to artifacts. CTA (median time after therapy, 28 months; range, 5–66 months) could provide a diagnosis in all cases, but confirmed the MRA diagnosis only in 50% of the cases. A residual nidus was shown in an additional six cases, and subtotal obliteration in another three cases. The interval between radiotherapy and the follow-up examination was significantly different ( P<0.05) between false- and true-negative MRA examinations (median, 18 vs. 30 months). Conclusion: High-contrast CTA is a sensitive tool in the detection of AVM and is able to identify residual AVM after radiotherapy even if previously performed TOF MRA at 1.5T shows total obliteration.
Comprehension of complex discourse in different stages of Huntington's disease
Authors: Saldert Charlotta , Fors Angelika , Ströberg Sofia , Hartelius Lena 
Published: January 2010

Background: Huntington's disease not only affects motor speech control, but also may have an impact on the ability to produce and understand language in communication.Aims: The ability to comprehend basic and complex discourse was investigated in three different stages of Huntington's disease.Methods & Procedures: In this experimental group study, 18 patients with Huntington's disease completed a test that assessed basic language abilities as well as tests from a battery of tasks that explored the ability to comprehend more complex information. The test battery assessed the ability to comprehend logico‐grammatical sentences, ambiguous information and inferred meaning on sentence and discourse levels.Outcomes & Results: In comparison with results from pair‐matched participants in a control group, matched for gender, age and education, the group of individuals with Huntington's disease had significantly more problems with all tasks requiring more complex cognitive processing. There was a correlation, as well as tendencies towards correlations, between results in the group of individuals with Huntington's disease and stage of the disease. However, results within the stage groups were heterogeneous, and some individuals in an early stage of the disease sometimes performed as well as others in a late stage.Conclusions & Implications: It is likely that, in complex discourse tasks, individual differences in cognitive capacity may contribute and override other differences related to stage of disease. These results indicate that it is important to assess comprehension even in early stages of Huntington's disease, with tests that are sensitive to subtle language disorders, to reduce communication problems for the individuals concerned and their conversational partners.