bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid–liquid extraction of uranium from nitric acid solution using di-n-butylsulfoxide in petroleum ether as extractant
Authors: Khan Muhammad Haleem , Shahida Shabnam , Ali Akbar 
Published: December 2007

A simple, efficient and economical liquid–liquid extraction method has been developed for quantitative extraction of uranium from 2 M HNO3using di-n-butyl sulfoxide in petroleum ether. The dependence of the partition reaction of U(VI) on the concentration of HNO3, extractant and temperature was studied. The reaction was found to be inversely dependent upon the temperature and the values for related thermodynamics functions (ΔH, ΔS, ΔG) for extraction equilibrium were determined to be -33.6 kJ/mol, -1.29 kJ/mol/degree and -0.11 kJ/mol/degree, respectively. The effect of Al(NO3)3as salting-out agent and diverse ions on the extraction was examined. The salting-out agent slightly enhanced the extraction. All cations studied have showed negligible effect on the extraction, whereas phosphate and fluoride interfered seriously. Among others, oxalate, citrate and sulphide ions affect the extraction to a lesser extent. Uranium was successfully extracted from a synthetic mixture of Ti+4, Zr+4, Hf+4and Th+4using EDTA as masking agent. Among strippants, deionized water was found most suitable, and the recovery of uranium was noted to be ≥96%. The stoichiometric composition of the extracted species was found to be UO2(NO3)2·2DBSO. The extraction mechanism is discussed on the basis of the results obtained. The extractant has high loading as well as recycling capacity without any degradation. The method was also applied to the Standard Reference Material (NBL-49) and the measured value was found to be in agreement with the reported value within ±2% deviation.
Species dependent radiotracer study of Cr(VI) and Cr(III) using an aqueous biphasic system
Authors: Roy Kamalika , Lahiri Susanta 
Published: December 2007

The speciation study of Cr(III) and Cr(VI) was carried out using a polyethylene glycol (PEG) based aqueous biphasic extraction system (ABS). Neutron activated Cr(III) and Cr(VI) salts were assayed in a HPGe detector before and after employing aqueous biphasic extraction. Different salts of various salting out abilities were taken as the salt rich phase. The best condition for extraction of Cr(VI) and the maximum differential attitude of ABS to Cr(VI) and Cr(III) was observed when 2 M Na2SO4 and PEG #4000 (50% w/w) solutions were used. Cr(III) can also be extracted by the PEG with prior complexation with diphenylthiocarbazone (dithizone). The chromium dithizonate complex is quantitatively extracted by the PEG rich phase.
177Lu-DOTMP: A viable agent for palliative radiotherapy of painful bone metastasis
Authors: Das Tapas , Chakraborty Sudipta , Sarma Haladhar D. , Banerjee Sharmila 
Published: December 2007

The suitable nuclear decay characteristics [T
1/2=6.73 d, E
β (max)=497 keV, E
γ=113 keV (6.4%), 208 keV (11%)] as well as the feasibility of large-scale production with adequate specific activity and radionuclidic purity using a moderate flux reactor are important attributes towards 177Lu to be considered as a promising radionuclide for palliative care in painful bone metastasis. The present study describes the preparation of 177Lu complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (DOTMP) and its preliminary biological evaluation in animal models with an aim to proposing it as a viable radiopharmaceutical for bone pain palliation. The choice DOTMP as the polyaminophosphonic acid carrier ligand is based on the enhanced thermodynamic stability and kinetic inertness of the metal-ligand complexes with macrocyclic chelators. 177Lu was produced with a specific activity of ∼12 GBq/mg (∼324 mCi/mg) and radionuclidic purity of 99.98% by irradiation of natural Lu2O3 target at a thermal neutron flux of ∼6×1013 n/cm2s for 21 d. 177Lu-DOTMP complex was prepared in high yield and excellent radiochemical purity (>99%) using DOTMP synthesized and characterized in-house. The complex exhibited excellent in-vitro stability at room temperature. Biodistribution studies in Wistar rats showed rapid skeletal accumulation of the injected activity [(1.60±0.19) per gram in femur at 3 h post-injection] with fast clearance from blood and minimal uptake in any of the major organs. Scintigraphic studies carried out in normal Wistar rats and New Zealand white rabbits also demonstrated significant accumulation of the agent in skeleton and almost no retention in any other vital organs.
Risk of Hospitalization for Acute Pancreatitis Associated with Conventional and Atypical Antipsychotics: A Population‐Based Case‐Control Study
Authors: Gasse Christiane , Jacobsen Jacob , Pedersen Lars , Mortensen Preben Bo , Nørgaard Mette , Sørensen Henrik Toft , Johnsen Søren Paaske 
Published: December 2007

Study Objective. To examine the association of atypical and conventional antipsychotics with the risk of hospitalization for acute pancreatitis.Design. Population‐based, case‐control study.Data Source. Health care databases of Northern Denmark.Patients. A total of 3083 adults hospitalized with acute pancreatitis (case patients) and 30,830 control subjects.Measurements and Main Results. Controls were selected from the general population by using risk‐set sampling and were matched to case patients by age and sex. The date of the case patients' admission for acute pancreatitis was used as the index date for the matched control subjects. Conditional logistic regression analysis was used to estimate rate ratios (RRs) for hospitalization due to acute pancreatitis in current users (0–90 days before admission or index date) and former users (> 90 days before admission or index date) of atypical and conventional antipsychotics compared with nonusers of the respective antipsychotics, while controlling for covariates and stratifying by age. Fifteen case patients (0.5%) were current users of atypical antipsychotics, and 128 case patients (4.2%) were current users of conventional antipsychotics. Adjusted RRs for current use and former use of atypical antipsychotics were 0.6 (95% confidence interval [CI] 0.3‐1.1) and 0.3 (95% CI 0.1‐0.9), respectively. A trend was noted for increasing risk of hospitalization due to acute pancreatitis with decreasing potency of conventional antipsychotics, with adjusted RRs of 1.2 (95% CI 0.7‐2.0) for high‐potency, 1.5 (95% CI 1.0–2.2) for intermediate‐potency, and 2.8 (95% CI 2.0–3.8) for low‐potency conventional antipsychotics, which was largely age‐modified with an adjusted RR of 5.2 (95% CI 3.2–8.5) in patients younger than 60 years, compared with an adjusted RR of 1.5 (95% CI 0.9‐2.5) in older users. Former use of conventional antipsychotics of any kind was associated with an adjusted RR of 1.6 (95% CI 1.4‐1.9).Conclusions. Current use of low‐potency conventional, but not atypical, antipsychotics was associated with an increased risk of hospitalization for acute pancreatitis.
Early Clinical Experience with Anidulafungin at a Large Tertiary Care Medical Center
Authors: Brielmaier Benjamin D. , Casabar Ed , Kurtzeborn Christine M. , McKinnon Peggy S. , Ritchie David J. 
Published: December 2007

Study Objective. To evaluate early clinical experience with anidulafungin.Design. Retrospective cohort study.Setting. Large, university‐affiliated, tertiary care medical center.Patients. All patients receiving anidulafungin between July 15, 2006, and January 15, 2007.Measurements and Main Results. Thirty‐five patients received at least one dose of anidulafungin. Safety and tolerability were evaluated in all patients; efficacy outcomes were assessed in 13 patients who had a documented fungal infection and received anidulafungin for a minimum of 5 days. Common conditions at baseline were hepatic dysfunction (25 patients [71%]), severe sepsis (17 patients [49%]), and solid organ or hematopoietic stem cell transplantation (10 patients [29%]). Eight patients (23%) were receiving drugs with the potential to interact with echinocandins other than anidulafungin. Seventeen (49%) of the 35 patients received anidulafungin as empiric antifungal therapy. Anidulafungin was used to treat invasive candidiasis in seven patients (20%) and candidemia in 10 patients (29%); Candida albicans or Candida glabrata was isolated most frequently in these two infections combined (7 isolates each [41%]/17 infections). A favorable efficacy outcome was noted in 10 (77%) of 13 evaluable patients. One patient developed breakthrough Candida parapsilosis fungemia while receiving anidulafungin. Overall, anidulafungin was well tolerated, with only one patient having an infusion‐related reaction. Anidulafungin was also well tolerated among patients receiving concomitant metronidazole.Conclusion. Anidulafungin was well tolerated and produced favorable outcomes in the majority of the patients evaluated. The availability of anidulafungin makes it a feasible option for antifungal therapy, particularly in patients who have hepatic dysfunction and in those who are receiving drugs than can interact with other echinocandins.
Unique Dielectric Properties Distinguish Stem Cells and Their Differentiated Progeny
Authors: Flanagan Lisa A. , Lu Jente , Wang Lisen , Marchenko Steve A. , Jeon Noo Li , Lee Abraham P. , Monuki Edwin S. 
Published: December 2007

Abstract
The relatively new field of stem cell biology is hampered by a lack of sufficient means to accurately determine the phenotype of cells. Cell-type-specific markers, such as cell surface proteins used for flow cytometry or fluorescence-activated cell sorting, are limited and often recognize multiple members of a stem cell lineage. We sought to develop a complementary approach that would be less dependent on the identification of particular markers for the subpopulations of cells and would instead measure their overall character. We tested whether a microfluidic system using dielectrophoresis (DEP), which induces a frequency-dependent dipole in cells, would be useful for characterizing stem cells and their differentiated progeny. We found that populations of mouse neural stem/precursor cells (NSPCs), differentiated neurons, and differentiated astrocytes had different dielectric properties revealed by DEP. By isolating NSPCs from developmental ages at which they are more likely to generate neurons, or astrocytes, we were able to show that a shift in dielectric property reflecting their fate bias precedes detectable marker expression in these cells and identifies specific progenitor populations. In addition, experimental data and mathematical modeling suggest that DEP curve parameters can indicate cell heterogeneity in mixed cultures. These findings provide evidence for a whole cell property that reflects stem cell fate bias and establish DEP as a tool with unique capabilities for interrogating, characterizing, and sorting stem cells.
Disclosure of potential conflicts of interest is found at the end of this article.
Two new species ofRetiskenea? (Gastropoda: Neomphalidae) from Lower Cretaceous hydrocarbon-seep carbonates of northern California
Authors: Campbell Kathleen A. , Peterson Dawn E. , Alfaro Andrea C. 
Published: December 2007

Two new Mesozoic gastropod species, provisionally attributed to the minute (height < 5 mm) coiled neomphalid genusRetiskenea?, are described from three geographically isolated, Early Cretaceous, hydrocarbon seep-carbonate sites at Wilbur Springs, Rice Valley, and Cold Fork of Cottonwood Creek, northern California (USA). A fourth paleo-seep locality at Paskenta, of probable Upper Jurassic age, also yielded a single specimen of a morphologically similar microgastropod that may be a neomphalid with affinities to the Lower Cretaceous specimens described herein. the limestone lenses are ~2-260 m in length, ~1-5 m in diameter, and surrounded by forearc siliciclastics of bathyal turbidites or sedimentary serpentinites in the Upper Jurassic to Lower Cretaceous (Tithonian-Albian) Great Valley Group and its equivalents. the Lower Cretaceous microgastropods are tentatively placed inRetiskenea?based on similar shell characters: size, globose shape, inflated reticulate protoconch, number and distinct inflation of the body whorls, and fine, prosocline sculpture of the final body whorl. the fossils occur in carbonate microbialites that formed in seafloor sediments during archaeal anaerobic oxidation of methane in the zone of bacterial sulfate reduction, associated with H2S- and CH4-rich fluid seepage. the CaliforniaRetiskenea?fossils commonly are found in gregarious clusters, or closely affiliated with thin worm tubes or, in one case, a larger gastropod.These Mesozoic records increase the total known species attributable to this cold-seep endemic genus from two to four. Its spatial and temporal distribution thus may have spanned ~9,000 km around the Pacific Rim from at least ~133 m.y. to the present in 10 subduction-related seep sites from California (possibly Upper Jurassic-Lower Cretaceous), Washington (middle Eocene-Upper Oligocene), and modern offshore Oregon, the eastern Aleutians, and the Japan Trench. If the generic placement of these microgastropod fossils is correct, the California records are the oldest-known occurrences ofRetiskenea, consistent with an estimated minimum Mesozoic origin for the 'hot vent' Neomphalidae, as inferred from molecular analyses published on other living members of the family.
Production Optimization through Coupled Facility/Reservoir Simulation
Authors: Hayder E. , Dahan M. , Dossary M. 
Published: December 2007

Abstract
Proper field management for optimal performance of hydrocarbon reservoirs must capture the interdependence of the subsurface reservoir behavior and surface facility constraints. In this work we describe how full coupling improved development of a Saudi field by reducing water production by 30% while maintaining the target plateau for the required period of time.
This was achieved by an iterative procedure that was able to devise an optimal producing strategy. The strategy involved time-dependent well production/injection rate allocations in response to field behavior. The strategy devised take into account production network constraints, network bottlenecks/under-utilization, and reservoir engineering complexities in producing three different reservoirs that make up the field.
This work was realized by linking Saudi Aramco's in-house developed simulator (POWERS) with a commercially available surface network simulator (PE-GAP). The paper will highlight some of the major challenges in creating the link from engineering as well as from software/hardware perspectives.
Due to this successful endeavor, the workflow will be applied to more fields. Furthermore connection to SCADA system for real-time monitoring is under developed.
Screening Criteria for Carbon Dioxide Huff ‘n’ Puff Operations
Authors: Mohammed-Singh L. , Singhal A. K. , Sim S. 
Published: December 2007

Abstract
This paper reviews design and performance data on sixteen (16) CO2 huff ‘n puff projects conducted in different wells in the Forest Reserve oilfield of Trinidad and Tobago over the last twenty (20) years. Specific inferences on conditions under which these projects succeeded in increasing oil production were generalized taking into account published results of similar projects elsewhere.
With a variety of technical, operational and economic variables, a strong correlation or a definitive conclusion is difficult. However, by correlating various performance attributes with different parameters, certain inferences are drawn and tested which could be used to: Determine if a candidate well could benefit from CO2 huff ‘n puff operations andIdentify optimal design and operational configurations in specific situations, based on field experience and engineering considerations.
Successful projects were conducted in reservoirs with crude oil gravities from 11-38°API and in-situ viscosities from 0.5 to 3000 cp (mPa.s) porosities of 11 to 32%, depths from 1150 to 12870 feet (345 to 3900 m), thicknesses from 6 to 220 feet (2 to 67 m) and permeabilities ranging from 10 to 2500 mD. Huff ‘n puff operations benefited from high oil saturations, mild pressure support to production, soak intervals of 2 to 4 weeks and production against back-pressures to discourage excessive water or gas production. Successful operations had CO2 utilization ranging from 0.3 Mcf/barrel to 10 Mcf/barrel for light oil reservoirs and 5 Mcf/barrel to 22 Mcf/barrel for some heavy oil reservoirs.
CO2 huff ‘n puff operations are essentially near wellbore stimulation techniques which can lead to increased oil recovery via removal of some productivity damage, reduced oil viscosity, increased dissolved gas content, oil swelling and vaporization of lighter components of oil. They can also suppress water production. They have significantly boosted short-term oil production and generated quick payouts, especially at attractive oil prices. In certain cases, they have also provided strategic information on injectivity and pressure communication with adjacent wells, and helped determine if a drive process is indicated. This paper attempts to demonstrate that by properly understanding relevant reservoir mechanisms, one can screen specific prospects and design appropriate operations.
Upscaling of Hydraulic Properties of Fractured Porous Media: Full Permeability Tensor and Continuum Scale Simulations
Authors: Rodriguez A. A. , Klie H. , Sun S. , Gai X. , Wheeler M. F. , Florez H. 
Published: December 2007

Abstract
The simulation of flow and transport phenomena in fractured media is a challenging problem. Despite existing advances in computer capabilities, the fact that fractures can occur over a wide range of scales within porous media compromises the development of detailed flow simulations. Current discrete approaches are limited to systems that contain a small number of fractures. Alternatively, continuum approaches require the input of effective parameters that must be obtained as accurately as possible, based on the actual fracture network or its statistical description.
In this work, a novel method based on the utilization of the Delta-Y transformation is introduced for obtaining the effective permeability tensor of a 2D fracture network. This approach entails a detailed description of the fracture network, where each fracture is represented as a segment with a given length, orientation and permeability value. A fine rectangular grid is then superimposed on the network, and the fractures are discretized so that each one of them is represented as a connected sequence of bonds on the grid with a hydraulic conductivity proportional to the ratio of effective permeability over fracture discretization length. The next step consists of the selection of a coarser rectangular grid on which the continuum simulation is performed. In order to obtain the permeability tensor for each one of the resulting blocks, the Delta-Y method is used.
Finally, the resulting continuum permeability tensor is used to simulate the steady-state flow problem, and the results are compared with the actual flow pattern yielded by the fracture network simulation. The results obtained with both methods follow a similar flux pattern across the reservoir system. This shows that the proposed approach allows for efficient perform upscaling of hydraulic properties by honoring both the underlying physics and details of fracture network connectivity.
Case Study: Lennox—The Race to Produce Oil Prior To Gas Cap Blowdown
Authors: Clarke A. , Ayton J. , Lawton D. , Lean J. , Burke K. 
Published: December 2007

Abstract
Ten years since production commenced from the Lennox Field and one year from the start of full gas cap blowdown, the challenge to produce oil from the Lennox oil rim has never been greater. The Lennox Field is one of six fields comprising the Liverpool Bay Development located in the UKCS, East Irish Sea. The Lennox oil rim is at a critical stage in the development of the asset as it transitions from an oil field to a gas field. The field was initially developed with horizontal and multi-lateral wells placed to maximise oil reserves and minimise movement of the gas-oil and oil-water contacts with re-injection of all produced gas to maintain reservoir pressure. Since other sources of gas in the area commenced their decline, Lennox must now sustain plateau nominated gas sales and as a result there is little time left to recover the remaining oil.
In a first for the development, a dual lateral well (110/15a-L13/L13z) was drilled in mid 2005 as a sidetrack to a poorly performing single bore well and completed with an intelligent completion to supply gas lift gas from the gas cap. The intelligent completion will assist the well to flow, maximise oil recovery and eventually allow a simple conversion to a gas well. The well was a success with better than expected reservoir intersections and the initial oil rate exceeding predictions. The project, initially designed to address unswept oil in the Lennox Field, was expanded to apply the artificial lift technology used at L13 to mature Lennox wells to allow continuous lift at higher watercuts and lower reservoir pressure. The result has highlighted the need to continually re-evaluate opportunities and challenge existing development plans and assumptions.
In-Situ Stresses Evaluation Using Well and Field Data: Integrated Methodology Approach
Authors: Pellegrino A. , Cappanera F. , Toscano C. 
Published: December 2007

Abstract
In the present paper we describe the workflow followed to estimate the field state of stress (FSS) for a well stimulation design in a faulted field. The customer demand was about the fracture gradients along the well-bore trajectories and about the fracture paths. To satisfy the customer demand an integrated study was performed using field data and well-bores evidences. On the base of available information a numerical model has been used that allows taking into account the complex geometry of the faults. The different FSS have been applied to three well-bores and the obtained break-outs have been compared to the observed ones. Two example of FSS, the worst and the best one, are illustrated and compared.
Wettability Alteration for Water-Block Prevention in High-Temperature Gas Wells
Authors: Panga M. K. R. , Ooi Y. S. , Koh P. L. , Chan K. S. , Enkababian P. , Chenevière P. , Samuel M. 
Published: December 2007

AbstractThis paper presents the development of a chemical system for water-block prevention in gas/condensate wells. The chemical system alters the formation wettability to intermediate gas wet conditions thereby decreasing the capillary forces and enhancing the clean up of trapped water at low drawdown pressures. Five different chemicals (A1-A5) are evaluated in this study for their ability to prevent water block formation at high temperature. Adsorption/desorption characteristics of these chemicals and temperature stability are also investigated for long-term prevention of water blocks. Contact angle and air-brine imbibition tests are conducted to determine wettability alteration before and after treatment with the chemicals. The results show that chemical A5 gives the best wettability alteration at high temperature with minimum formation damage. The improvement in water block removal after treatment with A5 is tested by injecting gas into brine-saturated cores at different pressure gradients and measuring volume of displaced brine. Higher volumes of brine clean up and lower flow initiation pressure gradient are observed after the treatment.