bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative Progressive Cavity Pump Design for Brown Fields in South of Oman
Authors: Al Shukri Mahmoud Said , Abou-ElKhair Abdel-Monaim
Published: May 2009

Most of the fields located in south of Oman are mature, sub-hydrostatic, producing viscous, and sandy oil. This has raised the need to deploy different artificial lifting mechanisms. Progressive Cavity Pump (PCP) is one of the lifting methods in use and unlike other lifting methods it has proved its capability to produce viscous oil and tolerates more with sand production. Besides, PCPs can be run deeper in deviated wells for better drawdown. Currently in South of Oman we have more than 400 PCP wells and by the end of 2013 the PCP population is expected to reach 1000 units.

South of Oman fields are characterised by being geologically complex and extremely heterogeneous due to existence of faults and fractures. Water flooding project was started to enhance oil recovery in those fields. To evaluate the success of water flood performance the wells require well intervention work such as coil tubing and wireline for well bore cleaning, well logging, selective water shut-off, re-perforation, and well stimulation. As completions needed to be removed, therefore in the past work could never be performed concurrently with production. The inability to evaluate water flood performance caused remedial work to become ineffective. The need for surveillance and an intervention string for the PCP drive completions were identified.

This paper presents the ideas developed to make concurrent production and well-intervention work with PCP completions is possible without interrupting production, including well kill. In this process, we looked at all aspects of PCP completions (Surface/ Subsurface) from running the completion to its maintenance. The design needed to overcome serious engineering challenges such as extremely tight surface tolerances with restricted geometries. The new design consists of an eccentric PCP drive head at surface, a downhole dual receptacle style torque anchor and housing for two parallel tubing strings. The innovative design was done locally by a multi-disciplinary team of PDO and local service companies. There was no appropriate solution available in the international market. The technology has been proven reliable on 10 wells and is now an integral part of a standard well design with 58 wells in planning as part of the Program Build for the year 2009.
Open Hole Sidetrack: A Transformation in Drilling Dual Lateral Khuff Reservoir Gas Wells in the Kingdom of Saudi Arabia
Authors: Nawaz Khalid , Al-Faraj Omar A. , Ajmi Naser A. , Awan A. H. , Verma Jaywant , Ganda Sukesh
Published: May 2009

This paper describes application of openhole sidetrack (OHSDTR) technique to drill deep gas multilateral horizontal wells in Saudi Arabia. The drawbacks of earlier whipstock exits were studied and an alternate technique was proposed and implemented.

The typical approach to drilling Khuff dual laterals was to drill the lower lateral and then set whipstock, and cut a window in the base Khuff-B and drill the upper lateral. Various problems observed using this technique were: Problem setting whipstock.Premature setting while running in holeProblem cutting the window. Mill twist offs leading to a long fishing operation; in some cases setting another whipstock and cutting another window.Milling the top of the whipstock while cutting the window leading to a severe problem in retrieving the whipstock.

Whipstock from different companies were tried, however, we could not get rid of multiple failures while milling and retrieving the whipstock. Even with modifications, a new whipstock system was tried in which milling was done in two parts; a first run with the milling machine to mill only the casing, and a second run with different mills to cut the window through to formation, but problems continued. Saudi Aramco and Schlumberger D&M came up with the idea of drilling dual laterals using an OHSDTR technique to avoid complication due to whipstock failure. Well HRDH-XYZ was the first successful dual lateral horizontal Khuff-C gas producer drilled with the open hole sidetrack technique, in a record time of 98.8 days against the 165 days planned, the technique saved $975,000 and two weeks of rig time.

This was a step change in drilling practice, to drill dual laterals saving considerable rig days to Saudi Aramco, and removing the time consuming whipstock operation to the extent of losing the well, due to unsuccessful whipstock retrieval. This technique brought a transformation in the way dual lateral wells were drilled in deep gas drilling in Saudi Arabia, later on similar technique was applied in drilling dual laterals in Khuff-B reservoir as well. Since the introduction of this technique on well HRDH-XYZ, 50 wells have been drilled successfully saving (approximately) 735 days to Saudi Aramco. This paper further details challenges; lesson learnt and success story about introduction of Open Hole Sidetrack in deep Gas drilling.
Evolution of Roller Cone Bit Design to Improve Performance in Carbonates
Authors: Senger Jim , AlRamahi Basil , Taha Islam Ahmed , Waheed Tamer
Published: May 2009

In the long tophole section of vertical wells in Abu Dhabi, formation challenges historically have caused roller cone bits to suffer impact and fatigue damage to the gage and cutting structure. As a result, at least two bits have been required to drill the 4000-foot section, which is composed mainly of carbonates with a thick anhydrite section.

In addition to high impact damage, the carbonates also generate high friction on bits that exacerbates thermal degradation to the cutting materials, launching a series of consequences that inevitably result in premature bit failure.

In addition, lost circulation is very common in this application, so determining optimum operating parameters is more challenging.

Given these conditions, the operator's stated objective was to drill the 17-1/2-in. interval "shoe-to-shoe" in a single bit run, optimizing penetration rate without compromising hole quality or cleaning efficiency.
Revitalization of Old Asset Oil Fields into I-Fields
Authors: Al-Khamis Mohammed N. , Zorbalas Konstantin I. , Al-Matouq Hassan M. , Almahamed Saleh M.
Published: May 2009

Recent evolution in oil field technologies has made a great revolution in the oil and gas industry all over the world leading to the emerging development of intelligent fields (I-Fields)1,2,3,4. The integration of I-Field technologies whether downhole or at surface, coupled with communication networks along with sophisticated simulation and monitoring applications has lead to significant advancements not only in monitoring and control capabilities, but rather also in decision making processes5. Therefore, the overall system upgrade has resulted in an enhancement of the field surveillance, which will lead to higher levels of oil production in these assets as a consequence of Saudi Aramco's development strategy for these fields.

A comprehensive redevelopment and I-Field transformation of three elderly remote onshore oil fields in Saudi Arabia has taken place where extensive drilling and workover programs have been reinitiated to complete both oil production and peripheral water injection wells, and equip them with the latest downhole production technologies. The project has also involved construction of new oil and gas processing and water injection facilities, which are being linked with the wells via a state of the art fiber optic communication network for controlling both subsurface and surface parameters and data surveillance in real-time. Further integration of I-Field components, such as Permanent Downhole Monitoring Systems (PDHMS), Smart Well Systems, Multiphase Flow Meters (MPFM), Single Phase Flow Meters, pressure and temperature sensors with specially tailored monitoring, and simulation software has facilitated the development and implementation of optimized production and injection strategies.

This paper will discuss the development strategy of the three fields sharing the lessons learned from this project. Moreover, examples, such as well performance monitoring and validation, crude blend assessment and assurance and reservoir pressure mapping, which are all being performed in real-time will be presented. In addition, this paper will also illustrate how the integration of I-Field components has effectively helped in optimizing the production from a portfolio of developed reservoirs.
Seismic Inversion Workflow for Sand Stringers Characterization in Offshore Saudi Arabia
Authors: Tonellot Thierry , Burnstad Roy , Fitzmaurice John
Published: May 2009

We describe an optimized seismic inversion workflow for an improved characterization of mid-Cretaceous sand stringers in the northern offshore area of Saudi Arabia. The first step of the workflow consists of analyzing the impact on inversion results for critical processing steps such as random and coherent noise reduction or prestack time migration. In a second step, a new "inversion friendly" processing sequence, including a patented in-house data reconstruction technique, is then defined in order to mitigate noise while preserving the recorded seismic amplitude variation with offset. The last step of the workflow consists of inverting the processed seismic dataset for Vp/Vs, and interpreting the results in terms of sand stringer probability. This workflow is illustrated on a dataset covering an area where one extended reach lateral is to be drilled.
Prediction of Sand Body Trend Based on Stratigraphic Dip Pattern from Microresistivity Images in Permian Sandstone Reservoir, Oman
Authors: Wang Da-Li , Al-Busaidi Salim , Lee Desmond N.H.
Published: May 2009

Stratigraphic dip patterns from high-resolution microresistivity images can indicate the paleocurrent direction of sediments transported by water and the associated depositional environment such as sand-filled stream channel and flood plain. This information was successfully used in the prediction of sand body orientation trends of an oil field in Oman. The interpretation and analysis of the stratigraphic dip patterns from the images complemented conventional seismic data and well logs in the sand body characterization. The sand body orientation trends were predicted from the oriented stratigraphic dip patterns of the sedimentary sandstone beddings observed on the images and the depositional energy analysis through the dip magnitudes of the beddings on the images, and the associated depositional environments were reconstructed using the sedimentary structures and textures on the images. The prediction and analysis of the sand body orientation trend finally provided the classification of the sand bodies that correspond to the different reservoir parameters for further field development.

The main contributor to hydrocarbon reserves and production in the field of North Oman is the sandstone reservoir of the Permian formation, which was dominantly formed in the fluvial and floodplain depositional environment. The uncertain sediment supply direction and complicated faults or sedimentologically confined compartments make reservoir characterization and modeling in the oil field very difficult, if not impossible, with only the traditional seismic data and well logs. In fact, the current field development demonstrates that in the oil field, the Permian sandstone reservoir contains structural traps and stratigraphic traps. Detailed sand body orientation trend is very important in further field development, but almost impossible using only conventional well logs and seismic data.

For the prediction of sand body trend in the case studies, firstly, the interpretation of the stratigraphic dip patterns was performed on each of the 30 wells, and secondly, the correlation of oriented sand bodies was analyzed within the multiwell scale of the field. Finally, from the multiwell correlation of oriented sand bodies, the sand body orientation trend was established. An improved understanding of sand body characterization and modeling in the field was obtained to reduce the risk of drilling unsuccessful wells.
Wettability Studies at the Pore Level of Saudi Aramco Reservoirs
Authors: Al-Shafei Mansour A. , Okasha Taha M.
Published: May 2009

The wettability of rocks is of critical importance in understanding reservoir dynamics. Several studies of wettability evaluation on Saudi Aramco reservoir rocks were reported, but to our knowledge, none of them have attempted to study wettability on the pore scale level. In this study wettability evaluation of carbonate rock samples of Saudi Aramco reservoirs were investigated using environmental scanning electron microscope (ESEM). The data obtained gives access to the distribution of oil and water in relation with mineral interface which can not be observed by normal techniques. It also improves the understanding of rock/fluid interaction.

In this study preserved rock samples from two distinct reservoirs (Arab-C and Shu'aiba) were used. The mineralogical analysis showed that the predominant minerals were calcite and dolomite in both samples. Determination of wettability using ESEM method is very cost effective. It is unlike other traditional methods. It doesn't use any chemical or even generate by-products; it is not time-consuming and provides better quality data at much lower cost.
Designing & Constructing a Pilot of Artificial Intelligent Well
Authors: Behrouz Turaj , Hendi Sayyed S.
Published: May 2009

Intelligent well technology was developed and commercialized in the 1990s as part of the global industry trend toward improving reservoir management. An intelligent well is a well that is equipped with sensors/ monitoring equipment and completion components that can be remotely adjusted to optimize production. This optimization of production typically involves flow control that takes place downhole via remote control from the surface, without physical intervention.

This paper aims to design and construct an artificial well with a close loop cycle that pressure, temperature and flow rate of the fluids can be monitored and controlled in real time. The height of the artificial well is about 6 meter and the maximum pressure and flow rate in this system is about 3000 psia & 2000 bopd. In this close loop system, pumps and pressure relief valves have been used for supplying pressure and flow rate can be controlled by variable throttle valve. For controlling the pressure and safety of the system, an auxiliary system, for flowing in emergency case, has been designed beside the main one. The outer and inner diameters of the tubes of the main flowing system were 3.5 and 4.25 inch respectively. Devices like electrical motor, pump, check valves and heat exchanger have been used. Once, remote operation has been chosen, the options for system architecture and communication are quite extensive.

In addition, a PVT software that named RNTTM has been developed during this project. This software can facilitate online access to data generated from the sensors, saving them and preparing the archives.

Finally, all the operations in this pilot like monitoring, interpretation and controlling for decision making in real time, that are key elements of the smart wells, can be accomplished in the control room that located far from the artificial well and it can be seen that the value loop of smart well has been closed in this small pilot.
Applications of a Multidomain, Integrated Tight Gas Field Development Process in North America and How To Adapt It to the Middle East
Authors: Aly Ahmed , Bukhamseen Raid , Ramsey Lee , Mesdour Rabah
Published: May 2009

Applying a multidomain integrated field management process in two diverse environments (North America and North Africa) has resulted in significant improvements in production optimization and planning of projects as simple as single-well completions all the way to field geocellular and simulation models. The multidomain process integrates data and activities from domains throughout the operation, enabling systematic and rigorous analysis and optimization of completions and drilling project.

Case studies from North America and the Middle East show applications of this process in two widely different environments (mature and emerging). The case from North America illustrates using the process in a high-volume field development to optimize the process and reach a "SMART"-factory-like process. Integrating technology results in the highest production recoveries while maximizing the net present value from the asset.

The case from the Middle East shows how collecting a broad range of adequate data early in the life of the field can impact development strategies and potentially costly decisions. The process offsets the challenges of collecting these data in an emerging environment where the services and the technology have not yet matured to the North America levels.
Tight Oil Reservoir Development Feasibility Study Using Finite Difference Simulation and Streamlines
Authors: Al-Salem Khalid M. , Ali Mansour A. Mohammed , Lin Chung
Published: May 2009

A scoping study was conducted to evaluate the feasibility of producing a tight oil reservoir. The subject reservoir was not included in the original development due to the lower rock quality. The team used a simulation model to evaluate the potential of this tight reservoir.

A detailed 4-million cell model was constructed for the study. The Assisted History Match tool (AHM) was used to auto-generate and auto-submit multiple runs in the process of evaluating key reservoir parameters, which helped speed up the history match cycle tremendously. Moreover, the in-house finite difference simulator could generate fluxes, and therefore a streamline simulation model was built. The streamlines could be displayed using software. The data gained from streamline models were essential in assessing the communication between injectors and producers in this tight reservoir. Injectors' placements were optimized based on this data and the most efficient injection plan was developed.

Initial results showed a commercial oil production with a 20-year plateau from the tight reservoir. Economics remained a major factor as many wells were initially required to achieve this rate. Through the use of streamline images and a different combination of well types, an optimum development plan was attained. Overall, the study showed that this tight reservoir has enough potential to be considered for future development.

The subject tight reservoir is part of a developed field where all infrastructures are in place. Adding a good level of oil production for 20 years is significant and will be very valuable.
Priority Assessment of Investment in Development of Nanotechnology in Upstream Petroleum Industry
Authors: Pourafshary P. , Azimpour S. S. , Motamedi P. , Samet M. , Taheri S. A. , Bargozin H. , Hendi S. S.
Published: May 2009

Nanotechnology is an emerging technology with the potential to effect revolutionary changes in several aspects of the oil and gas industry. While the advantages of nanotechnology in several small-scale downstream sections of the industry is well established, policy makers in the upstream section often tend to adopt a more conservative approach towards the emerging technologies. This is chiefly rooted in the comparatively extensive investments needed to impose any fundamental technology changes in this section, and the high level of economical risk involved.

However, since the impacts of any widespread technological revolution will be inevitably felt in every large-scale industry, adopting an astute strategy in regard to the incoming tides is of utmost importance. Such a strategy must determine the areas most prepared to accept technological changes so that the emerging technology will be accepted in a premeditated manner, minimizing the associated risks.

Regarding these considerations, in the present study, an extensive literature survey was conducted, with the aim of discerning those sections of the upstream oil and gas industry, where nanotechnology is potentially advantageous in providing technically and economically viable alternatives for present materials and technologies. This survey led to creation of a Technology Tree, which demonstrates these fields with the associated organic connections among them.

In the next step, a priority assessment was carried out to determine those areas of upstream industry most suitable for investment. For this aim, comprehensive questionnaires were prepared and distributed among a number of experts in nanotechnology and energy policy making. The pool of experts were carefully handpicked, so that the selected individuals would have considerable experience and expertise in fields such as nanotechnology, upstream oil industry, technology management and policy making.

The gathered feedback was then analyzed according to the AHP model, using software specifically engineered by the authors to include all the necessary criteria. At the end, a select-few of fields were found to have the highest priority for investment. Among these were Chemical EOR, i.e. application of polymeric nanocomposites specifically hydrogel nanocomposites for enhanced and improved oil recovery and taking advantage of nanostructured materials in producing high-efficiency water-based drilling fluids.
Calibrating Reflectance Measurements to Predict Optimal Sidedress Nitrogen Rate for Corn
Authors: Scharf Peter C. , Lory John A.
Published: May 2009

Optimal N fertilizer rate for corn (Zea mays L.) and other crops can vary substantially within and among fields. Current N management practices do not address this variability. Nitrogen‐stressed corn reflects more visible light than N‐sufficient corn, possibly providing a basis for diagnosing optimal sidedress N rate in a growing crop. Our objective was to calibrate reflectance measurements to predict economically optimal N rate (EONR) of corn in Missouri. We conducted eight field experiments with N rate treatments in which reflectance was measured at the V6 growth stage in plots that had received 0, 110, or ≥220 kg N ha−1 at planting. Reflectance was measured in eight wavebands (510–830 nm) using a passive radiometer in three orientations (straight down, angled forward, and angled diagonally across rows). Reflectance ratios (relative to reflectance from high‐N plots) were necessary to produce good relationships with EONR. We observed r2 from 0.56 to 0.76 between relative reflectance and EONR for all visible (510–710 nm) wavelengths in all measurement orientations except 610 diagonal. The highest r2 values were observed for relative 510‐, 560‐, and 710‐nm reflectance in the straight down orientation. The straight down orientation is preferable for use in field applications because it gave predictions as good as or better than the other orientations, while avoiding the complexities associated with angled orientations. Combinations of wavelengths did not have a stronger relationship with EONR than individual visible wavelengths, but all visible/NIR ratios gave r2 ≥ 0.43 in all orientations, with many above 0.6. Calibrations such as those presented here could be used to convert reflectance measurements to N rate recommendations during variable‐rate sidedressing of corn.
Prospects of Developing Hybrid Rice with Super High Yield
Authors: Wu Xiaojin
Published: May 2009

Approaches to develop hybrid rice (Oryza sativa L.) with super high yield involve the improvement of plant type, the exploitation of intersubspecific heterosis, the pyramiding of heterosis genes in different rice ecotypes, and the utilization of favorable genes from distant relatives. Three main plant types have been suggested in the literature for improving hybrid rice yield: (i) heavy panicle type, (ii) super high yielding plant type, and (iii) super high yielding ideotype. Recently, intersubspecific heterosis has been partially exploited with three strategies: (i) developing parental lines of indica‐japonica intermediate type with favorable genes from both parents, (ii) introgressing intersubspecific gene with the help of wide compatibility and thermosensitive genic male sterility (TGMS) genes, and (iii) breeding pro‐indica japonica lines. It is also possible to pyramid different heterosis genes from various rice ecotypes through molecular marker aided reciprocal recurrent selection. The identification of yield enhancing genes from wild rice, the construction of autoregulated senescence delaying gene, and the cloning of key enzymes related to C4 pathway have been accomplished using molecular biotechnology. By introducing these genes into the parents of the hybrid rice, the heterosis of the hybrid rice can be dramatically improved.
Phosphorus Source Effects on Corn Utilization and Changes in Soil Test
Authors: Sneller Emily G. , Laboski Carrie A. M.
Published: May 2009

Estimating crop availability of manure P and changes in soil test P (STP) with manure application are essential components of nutrient management planning. The objectives of this field study were to (i) evaluate manure P availability to crop growth through crop P uptake and yield; (ii) determine if second‐year residual P availability from manure application is different than fertilizer; and (iii) evaluate the effect of P source on changes in STP levels. Research plots were established at Arlington and Marshfield, WI, in 2005 on fields with low STP. All P sources (dairy slurry, dairy solid, swine slurry, pelletized poultry litter, and fertilizer) were applied at three target rates of 39, 79, 118 kg total P ha−1 in spring 2005 before planting corn (Zea mays L.). No additional P was applied in 2006. Phosphorus application increased early season biomass, silage and grain yield, and P uptake. In 2005, all manures had silage and grain yields and P uptakes, along with silage P recoveries, that were not significantly different than fertilizer. In 2006, the residual effect of 2005 P applications rates were observed; however, there was no significant difference in any measure of crop response between any manure and fertilizer. These data suggest that manure total P is as available to corn as fertilizer P in the year of application and in the following year. Manure application changed STP levels as much as fertilizer in terms of total P applied.
Cotton Response to Chicken Litter in Rotation with Corn in Clayey Soil
Authors: Tewolde H. , Buehring N. , Adeli A. , Sistani K. R. , Rowe D. E. , Pratt R. G.
Published: May 2009

Poultry litter may benefit continuous cotton (Gossypium hirsutum L.) production in the heavier Midsouth soils in the same way as crop rotation. The objective of this research was to determine the effectiveness of poultry litter in maintaining yield of continuous cotton compared with cotton‐corn (Zea mays L.) rotation in the Black Belt Prairie clay soils of Mississippi. The research was conducted in a Catalpa silty clay loam soil in northern Mississippi. Three main plots with the sequence cotton‐cotton‐cotton, cotton‐corn‐cotton, and corn‐cotton‐cotton in 2003–2004–2005 were split into five subplots each of which received 0, 4.5, 9.0, 13.5 Mg litter ha−1 yr−1, or 123 kg N ha−1 yr−1 as urea‐ammonium nitrate solution (32% N; UAN) (conventional inorganic fertilization, CIF). The CIF received 180 kg ha−1 UAN‐N when planted with corn. The results showed 3‐yr continuous cotton produced about the same lint yield as cotton that followed corn or 1 yr cotton. Unlike soils in other locations where ≤9.0 Mg ha−1 litter was adequate to produce yield equal to standard inorganic fertilization, cotton in this soil responded to litter up to 13.5 Mg ha−1, which suggests lint yield in this clayey soil may be optimized with greater litter fertilization rate than in lighter soils. Cotton fertilized with 13.5 Mg ha−1 litter, regardless of the rotation, outyielded the CIF by up to 26%. Overall, the results show adequate fertilization with poultry litter may be more important to improving and maintaining lint yield in this soil than the perceived benefit of a short‐term rotation with corn.
Effect of Intensive Insulin Therapy Using a Closed-Loop Glycemic Control System in Hepatic Resection Patients
Authors: Okabayashi Takehiro , Nishimori Isao , Maeda Hiromichi , Yamashita Koichi , Yatabe Tomoaki , Hanazaki Kazuhiro
Published: May 2009

OBJECTIVE

Intensive insulin therapy (IIT) reduces morbidity and mortality in patients in surgical intensive care units. The aim of this study is to assess the effect of IIT using a closed-loop system in hepatectomized patients.

RESEARCH DESIGN AND METHODS

Patients were randomly assigned to receive IIT using a closed-loop system: an artificial pancreas (AP group) or conventional insulin therapy using the sliding-scale method (SS group).

RESULTS

The incidence of surgical-site infection in the AP group was significantly lower than that in the SS group. The length of hospitalization required for patients in the AP group was significantly shorter than that in the SS group.

CONCLUSIONS

Total hospital costs for patients in the AP group were significantly lower than for patients in the SS group. IIT using a closed-loop system maintained near-normoglycemia and contributed to a reduction in the incidence of SSI and total hospital costs due to shortened hospitalization.
Improved Glycemic Control With Intraperitoneal Versus Subcutaneous Insulin in Type 1 Diabetes
Authors: Logtenberg Susan J. , Kleefstra Nanne , Houweling Sebastiaan T. , Groenier Klaas H. , Gans Reinold O. , van Ballegooie Evert , Bilo Henk J.
Published: May 2009

OBJECTIVE

Continuous intraperitoneal insulin infusion (CIPII) with an implantable pump has been available for the past 25 years. CIPII, with its specific pharmacodynamic properties, may be a viable treatment alternative to improve glycemic control in patients with type 1 diabetes for whom other therapies have failed. There have been few studies in which CIPII was compared with subcutaneous insulin treatment for patients with type 1 diabetes with poor glycemic control.

RESEARCH DESIGN AND METHODS

In an open-label, prospective, crossover, randomized, 16-month study, the effects of CIPII and subcutaneous insulin were compared in 24 patients. The primary outcome measure was the incidence of hypoglycemia. Secondary outcome measures were A1C, and glucose profile, including time in euglycemia, as measured by continuous glucose monitoring.

RESULTS

The incidence of grade 1 hypoglycemic events was 4.0 ± 2.6 per week with subcutaneous insulin compared with 3.5 ± 2.3 per week during CIPII (P = 0.13). The absolute mean difference in A1C with CIPII compared with subcutaneous treatment was −0.76% (95% CI −1.41 to −0.11) (P = 0.03). Baseline time spent in euglycemia was 45.2 ± 12.6% and increased 10.9% (4.6–17.3) with CIPII compared with subcutaneous treatment (absolute value; P = 0.003). There were no differences in the occurrence rate for severe hypoglycemic events, daily insulin use, or BMI. No pump or catheter malfunction was observed during the study.

CONCLUSIONS

Although we did not observe a significant reduction in hypoglycemic events, improved glycemic control was achieved with the use of CIPII. We saw a 0.8% decrease in A1C and an 11% increase in the time spent in euglycemia.
The Effect of Continuous Glucose Monitoring in Well-Controlled Type 1 Diabetes
Authors:   Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group
Published: May 2009

OBJECTIVE

The potential benefits of continuous glucose monitoring (CGM) in the management of adults and children with well-controlled type 1 diabetes have not been examined.

RESEARCH DESIGN AND METHODS

A total of 129 adults and children with intensively treated type 1 diabetes (age range 8–69 years) and A1C <7.0% were randomly assigned to either continuous or standard glucose monitoring for 26 weeks. The main study outcomes were time with glucose level ≤70 mg/dl, A1C level, and severe hypoglycemic events.

RESULTS

At 26 weeks, biochemical hypoglycemia (≤70 mg/dl) was less frequent in the CGM group than in the control group (median 54 vs. 91 min/day), but the difference was not statistically significant (P = 0.16). Median time with a glucose level ≤60 mg/dl was 18 versus 35 min/day, respectively (P = 0.05). Time out of range (≤70 or >180 mg/dl) was significantly lower in the CGM group than in the control group (377 vs. 491 min/day, P = 0.003). There was a significant treatment group difference favoring the CGM group in mean A1C at 26 weeks adjusted for baseline (P < 0.001). One or more severe hypoglycemic events occurred in 10 and 11% of the two groups, respectively (P = 1.0). Four outcome measures combining A1C and hypoglycemia data favored the CGM group in comparison with the control group (P < 0.001, 0.007, 0.005, and 0.003).

CONCLUSIONS

Most outcomes, including those combining A1C and hypoglycemia, favored the CGM group. The weight of evidence suggests that CGM is beneficial for individuals with type 1 diabetes who have already achieved excellent control with A1C <7.0%.
Bianchi type-I string cosmological model in the presence of a magnetic flux: exact and qualitative solutions
Authors: Saha Bijan , Rikhvitsky Victor , Visinescu Mihai
Published: May 2009

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmological string is investigated. The objective of this study is to generate solutions to the Einstein equations using a few tractable assumptions usually accepted in the literature. The analytical solutions are supplemented with numerical and qualitative analysis. In the frame of the present model the evolution of the Universe and other physical aspects are discussed.
Gain-controlled wave chaos in a chaotic optical fibre
Authors: Michel C. , Tascu S. , Doya V. , Legrand O. , Mortessagne F.
Published: May 2009

In this paper, we present a non-standard fibre amplifier specially designed to amplify scar modes of a multimode chaotic optical fibre. More precisely, we introduce Ytterbium in the optical fibre as a gain medium localised on the maximum of intensity of the scar modes. After briefly recalling the relevance of a chaotic optical fibre as a device to visualise quantum chaos, we describe the amplification process of scars. We present some numerical results that demonstrate the selective amplification of scar modes, with an amplification rate proportional to the overlap between these modes and the gain area.
Scattering cancellation by metamaterial cylindrical multilayers
Authors: Tricarico Simone , Bilotti Filiberto , Vegni Lucio
Published: May 2009

In this paper, we present the theoretical analysis and the design of cylindrical multilayered electromagnetic cloaks based on the scattering cancellation technique. We propose at first the analysis and the design of bi-layered cylindrical shells, made of homogenous and isotropic metamaterials, in order to effectively reduce the scattered field from a dielectric cylindrical object. The single shell and the bi-layered shell cases are compared in terms of scattering reduction and loss effects. The comparison shows that the bi-layered configuration exhibits superior performances. The scattering cancellation approach, is, then, extended to the case of generic multilayered cylindrical shells, considering again homogeneous and isotropic metamaterials. The employment of the proposed technique to the case of cloaking devices working at multiple frequencies is also envisaged and discussed. Finally, some practical layouts of cylindrical electromagnetic cloaks working at optical frequencies are also proposed. In these configurations, the homogenous and isotropic metamaterials are replaced by their actual counterparts, obtained using alternating stacked plasmonic and non-plasmonic layers. The theoretical formulation and the design approaches presented throughout the paper are validated through proper full-wave numerical simulations.
Liquid level sensing by use of digital formatted optical spectrum spreading technique
Authors: Zhang W. , Sugden K. , Grice S. , Bennion I.
Published: May 2009

We propose a novel technique for optical liquid level sensing. The technique takes advantage of an optical spectrum spreading technique and directly measures liquid level with a digital format. The performance of the sensor does not suffer from changes of environmental variables and system variables. Due to its distinct measurement principle both high resolution and a large measurement range can be achieved simultaneously.
Recurrent intraparenchymal hemorrhages from angiographically occult vascular malformations
Authors: Tung Howard , Giannotta Steven L. , Chandrasoma Parakrama T. , Zee Chi-Shing
Published: May 2009

✓ Thirteen patients with recurrent hemorrhages from angiographically occult vascular malformations are presented. Recurrent hemorrhages were indicated by the exacerbation of neurological deficits, the appearance of a new neurological deficit, or the onset of acute severe headache confirmed by evidence of recent hemorrhage on either computerized tomography or magnetic resonance imaging. Persistent neurological deficits correlated with an increased number of recurrent hemorrhages and their location. The median time from initial hemorrhage to the first recurrent hemorrhage was 12 months and the second rebleed generally occurred much earlier, with a median time of 2 months after the first. Eight patients underwent surgery with total excision and favorable results. One patient with a large pontine lesion underwent partial excision and has had a progressing neurological deficit from recurrent hemorrhages. Histopathological review confirmed the excised lesions to be cavernous angiomas. The authors conclude that angiographically occult vascular malformations are not the benign entity they were previously thought to be, and that they are prone to cause recurrent hemorrhages and persistent neurological deficits. Surgery can be effective and relatively safe in removing these lesions even in eloquent areas of the brain, but the necessity of occasional incomplete removal must be recognized in order to avoid creating an unacceptable neurological outcome.
Myxomatous cyst of the brachial plexus
Authors: Arnold Paul M. , Oldershaw John B. , McDonald Larry W. , Langer Bradley G.
Published: May 2009

✓ The case of a myxomatous cyst of the brachial plexus is presented. The clinical course is reported, and the frequency of the lesion, diagnostic workup, histopathology, and surgical therapy are discussed.
Immunosuppression for neural xenografts: a comparison of cyclosporin and anti-CD25 monoclonal antibody
Authors: Honey Christopher R. , Shen Hao
Published: May 2009

Object. The goal of this study was to compare the effects of short- and long-term immunosuppression induced by cyclosporin with those of immunosuppression induced by a monoclonal antibody against the rat interleukin-2 receptor (anti-CD25 mAb) in rats with xenografts.

Methods. The authors compared the in vivo function and final histological characteristics of fetal mouse mesencephalon xenografts in hemiparkinsonian rats in which immunosuppression was induced by: 1) a short course (2 weeks) of cyclosporin; 2) a long course (8 weeks) of cyclosporin; or 3) a short course of treatment with anti-CD25 mAb. Adult Wistar rats were unilaterally lesioned with 6-hydroxydopamine in their medial forebrain bundle, after which their rotational behavior in response to methamphetamine was quantified. Four groups of 20 rats with rotations numbering greater than six turns per minute received fetal mouse mesencephalon transplants to their dopamine-denervated striatum. Group 1 received no immunosuppression therapy; Group 2 received daily intraperitoneal injections of 10 mg/kg cyclosporin for 2 weeks; Group 3 received daily intraperitoneal injections of 10 mg/kg cyclosporin for 8 weeks; and Group 4 received daily intraperitoneal injections of 1 mg/kg anti-CD25 mAb for 2 weeks. The rats were tested for rotational behavior every 4 weeks and killed after 16 weeks. Surviving xenografts were assessed using immunohistochemical staining for a mouse neuronal marker (Thy-1.2). Sixteen weeks after transplant, there were significantly more surviving xenografts in Groups 3 (p < 0.001) and 4 (p < 0.001) compared with control Group 1 (Fisher's exact test) and significantly better functioning xenografts in Groups 3 (p < 0.01) and 4 (p < 0.05) compared with control Group 1 (contrasts of groups following analysis of variance with Bonferroni correction).

Conclusions. A short course of anti-CD25 mAb—induced immunosuppression was as effective as a long course of cyclosporin-induced immunosuppression in this model.
Detailed magnetic resonance imaging anatomy of the cisternal segment of the abducent nerve: Dorello's canal and neurovascular relationships and landmarks
Authors: Yousry Indra , Camelio Salvador , Wiesmann Martin , Schmid Urs D. , Moriggl Bernhard , Brückmann Hartmut , Yousry Tarek A.
Published: May 2009

Object. The goal of this study was to identify reliably the cisternal segment of the abducent nerve by using the three-dimensional Fourier transform constructive interference in steady-state (3-D CISS) magnetic resonance (MR) imaging sequence to define landmarks that assist in the identification of the abducent nerve on MR imaging and to describe the nerve's relationship to the anterior inferior cerebellar artery (AICA).

Methods. A total of 26 volunteers underwent 3-D CISS MR imaging, and 10 of these volunteers also underwent MR angiography in which a time-of-flight sequence was used to identify the facial colliculus, the abducent nerve and its apparent origin, Dorello's canal, and the AICA.

The authors identified the abducent nerve with certainty in 96% of 3-D CISS sequences obtained in the axial and sagittal planes and in 94% obtained in the coronal plane. The nerve emerged from the pontomedullary sulcus in 94% of cases. The facial colliculus could always be identified, and Dorello's canal was identified in 94% of cases. In 76.6% of cases, the abducent nerve was seen to contact the AICA, which passed inferior to the nerve in 63.8% of cases and superior to it in 29.8%.

Conclusions. The anatomical course of the abducent nerve and its relationship to the AICA and other blood vessels can be reliably identified using a 3-D CISS MR sequence with the facial colliculus and Dorello's canal serving as landmarks.
Three-dimensional computerized tomography angiography in patients with hyperacute intracerebral hemorrhage
Authors: Murai Yasuo , Takagi Ryo , Ikeda Yukio , Yamamoto Yasuhiro , Teramoto Akira
Published: May 2009

Object. The authors confirm the usefulness of extravasation detected on three-dimensional computerized tomography (3D-CT) angiography in the diagnosis of continued hemorrhage and establishment of its cause in patients with acute intracerebral hemorrhage (ICH).

Methods. Thirty-one patients with acute ICH in whom noncontrast and 3D-CT angiography had been performed within 12 hours of the onset of hemorrhage and in whom conventional cerebral angiographic studies were obtained during the chronic stage were prospectively studied. Noncontrast CT scanning was repeated within 24 hours of the onset of ICH to evaluate hematoma enlargement.

Findings indicating extravasation on 3D-CT angiography, including any abnormal area of high density on helical CT scanning, were observed in five patients; three of these demonstrated hematoma enlargement on follow-up CT studies. Thus, specificity was 60% (three correct predictions among five positives) and sensitivity was 100% (19 correct predictions among 19 negatives). Evidence of extravasation on 3D-CT angiography indicates that there is persistent hemorrhage and correlates with enlargement of the hematoma.

Regarding the cause of hemorrhage, five cerebral aneurysms were visualized in four patients, and two diagnoses of moyamoya disease and one of unilateral moyamoya phenomenon were made with the aid of 3D-CT angiography. Emergency surgery was performed without conventional angiography in one patient who had an aneurysm, and it was clipped successfully.

Conclusions. Overall, 3D-CT angiography was found to be valuable in the diagnosis of the cause of hemorrhage and in the detection of persistent hemorrhage in patients with acute ICH.
Magnetic resonance imaging compatibility testing of intracranial pressure probes
Authors: Williams Emma J. , Bunch Cliff S. , Carpenter T. Adrian , Downey Stephen P. M. J. , Kendall Iona V. , Czosnyka Marek , Pickard John D. , Martin John , Menon David K.
Published: May 2009

✓ There is increasing recognition that magnetic resonance (MR) imaging and spectroscopy may provide important information in the assessment of patients with acute brain injury. However, optimum care of the acutely head injured patient requires monitoring of intracranial pressure (ICP). Although many monitoring modalities have been integrated into commercially available MR-compatible systems, there have been no reports of commonly used intraparenchymal ICP sensors in an MR environment. The authors describe the use of an ICP micromanometer probe in an MR environment, with a fiberoptic connection that interfaces the probe with a commercially available MR-compatible monitoring system. Phantom studies were performed to demonstrate the safety and compatibility of the modified MR system at 0.5 tesla. The safety of the device was assessed in relation to its interaction with the static, gradient, and radiofrequency fields used in MR imaging. The MR compatibility was documented by demonstrating that its performance was unaffected by the operation of imaging sequences and by showing that there was no degradation of the diagnostic quality of imaging data obtained during ICP monitoring.
Glioblastoma multiforme in a case of acquired immunodeficiency syndrome: investigating a possible oncogenic influence of human immunodeficiency virus on glial cells
Authors: Vannemreddy Prasad S. S. V. , Fowler Marjorie , Polin Richard S. , Todd John R. , Nanda Anil
Published: May 2009

✓ Malignant glioma is the most common primary brain neoplasm, but generally it is not included in the differential diagnosis of enhancing lesions of the central nervous system (CNS) in patients suffering from acquired immunodeficiency syndrome. We report a case of glioblastoma multiforme (GBM) in a 29-year-old man with human immunodeficiency virus (HIV). Primary CNS lymphoma was suspected, making a definitive histological diagnosis crucial. An initial stereotactic biopsy sample was insufficient to establish a diagnosis and a second biopsy of the lesion was obtained. The histopathological investigation confirmed GBM and adjuvant external radiation treatment was given to the patient, who survived for 4 months after the initial biopsy. A decline in the rate of Toxoplasma infection and the changing diseases observed in HIV infection indicate the importance of obtaining a biopsy in cases of CNS mass lesions.
Pallidal stimulation for generalized dystonia
Authors: Tronnier Volker M. , Fogel Wolfgang
Published: May 2009

✓ Pallidal stereotactic surgery is a well-accepted treatment alternative for Parkinson's disease. Another indication for this procedure is medically refractory dystonia, especially generalized dystonia with abnormal axial and extremity movements and postures. Improvement of dystonia after pallidotomy has been reported in several recent papers. In this report the authors describe three patients with generalized dystonia (two primary, one secondary) and their improvement after bilateral pallidal stimulation at follow-up times of between 6 and 18 months.
Thalamic stimulation for choreiform movement disorders in children
Authors: Thompson Todd P. , Kondziolka Douglas , Albright A. Leland
Published: May 2009

✓ Surgery for movement disorders is most commonly performed in patients with dyskinesia and tremor associated with Parkinson's disease or in those with essential tremor. The role of ablative surgery or deep brain stimulation in patients with choreiform movements is poorly defined.

The authors placed thalamic stimulation systems in two children with disabling choreiform disorders due to intracerebral hemorrhage or cerebral palsy. Each patient displayed choreiform movements in the upper extremities both at rest and with intention, which interfered with daily activities and socialization. Both children obtained significant improvement in their choreiform movements, and their upper extremity function improved with no incidence of morbidity. Thalamic stimulation appears to be a promising and nonablative approach for children with choreiform movement disorders.