bluuebunny/crossref_metadata_2025 huggingface dataset:
Maintaining Steerability While Extending Gauge Length To Manage Whirl
Authors: Dupriest Fred E. , Sowers Steven F.
Published: June 2010

This paper discusses the results of a global campaign to increase the length of the gauge area of bits used on rotary-steerable systems (RSSs) to mitigate bit whirl and its undesirable effects. The desired steerability was achieved with lengths in excess of 4 in. with all RSS tools used. The modifications have resulted in reduced vibrations, significant improvement in drill rate, improved borehole quality, and reduced tool damage.

When the operator's performance-management process was implemented, real-time and post-drill analysis of mechanical specific energy (MSE) suggested 40% of footage drilled worldwide was affected by bit whirl or lateral instability. One element in the programmatic response was an initiative beginning in 2006 to extend bit-gauge lengths to constrain side cutting and reduce the amplitude of whirl-induced patterns. The value of extended gauge lengths has been demonstrated in numerous papers. However, field implementation by the industry has not been uniform, and a significant issue has been concern that steerability would be reduced. The purpose of the initiative was to demonstrate that common build rates could be achieved with all RSS tools used by the operator with bits having a minimum gauge length of 4 in. In the subject wells over a 2-year period, normal build rates (2-4°/100 ft) were not affected with 4-in. gauges if the profile and aggressiveness were designed properly. The gauge profiles used to maintain steerability included full taper, full undercut, and partial undercut. While the desired steerability was achieved with both point-the-bit and push-the-bit RSS tools, specific modification required in the gauge profile varied with the RSS used, desired build rate, and drilling environment. Drill-rate performance and bit life also improved, but this was attributed partly to implementation of the performance-management process and specific rig-crew training. Extension of the gauge length is also known to benefit bent-motor operations (Norris et al. 1998); however, the effects of various gauge profiles are less certain, and motor operations are not discussed in this paper.

The objective was not to determine the maximum build rates achievable but to simply confirm that gauge lengths of 4 in. or greater could be used as standard practice in normal operations. This paper discusses the rationale for the use of extended gauges, the modified profiles used to maintain steerability with various RSS tools, and the field performance achieved.
Evaluation of Renewable Energy as a Source of Power for Desalination of Remote-Oilfield Brines
Authors: Barrufet Maria A. , Mareth Brett C.
Published: June 2010

A hybrid system of wind, solar, and diesel generators could provide an efficient alternative for powering water-desalination projects in remote-oilfield locations in Texas, USA. Disposal of produced water from oil and gas wells is a costly procedure for production companies, but water-to-oil production ratios exceed 10:1 (by volume) at many wellsites. Much of the petroleum produced in the United States and elsewhere is found in arid regions that could benefit greatly if the produced water could be purified sufficiently for agricultural, industrial, or potable use. Our previous research identified and validated treatment options capable of recovering a high proportion of fresh water from oilfield brine. In this paper, we extend the earlier research further by examining the possibility of using renewable energy to power the units in "off-the-power-grid" situations. A macro-driven spreadsheet was created to allow for quick and easy cost comparisons of renewable energy sources for a variety of scenarios. Using this tool, wind and solar costs were compared for cities in regions throughout Texas. The renewable energy resource showing the greatest potential was wind power, with the analysis showing that in windy regions such as the Texas Panhandle, wind-generated-power costs are lower than those associated with diesel-fuel generation.
Stability of Partially Hydrolyzed Polyacrylamides at Elevated Temperatures in the Absence of Divalent Cations
Authors: Seright R. S. , Campbell A. R. , Mozley P. S. , Han Peihui
Published: June 2010

At elevated temperatures in aqueous solution, partially hydrolyzed polyacrylamides (HPAMs) experience hydrolysis of amide side groups. However, in the absence of dissolved oxygen and divalent cations, the polymer backbone can remain stable so that HPAM solutions were projected to maintain at least half their original viscosity for more than 8 years at 100°C and for approximately 2 years at 120°C. Within our experimental error, HPAM stability was the same with and without oil (decane). An acrylamide-AMPS copolymer [with 25% 2-acrylamido-2-methylpropane sulphonic acid (AMPS)] showed similar stability to that for HPAM. Stability results were similar in brines with 0.3% NaCl, 3% NaCl, or 0.2% NaCl plus 0.1% NaHCO3. At temperatures of 160°C and greater, the polymers were more stable in brine with 2% NaCl plus 1% NaHCO3 than in the other brines. Even though no chemical oxygen scavengers or antioxidants were used in our study, we observed the highest level of thermal stability reported to date for these polymers. Our results provide considerable hope for the use of HPAM polymers in enhanced oil recovery (EOR) at temperatures up to 120°C if contact with dissolved oxygen and divalent cations can be minimized.

Calculations performed considering oxygen reaction with oil and pyrite revealed that dissolved oxygen will be removed quickly from injected waters and will not propagate very far into porous reservoir rock. These findings have two positive implications with respect to polymer floods in high-temperature reservoirs. First, dissolved oxygen that entered the reservoir before polymer injection will have been consumed and will not aggravate polymer degradation. Second, if an oxygen leak (in the surface facilities or piping) develops during the course of polymer injection, that oxygen will not compromise the stability of the polymer that was injected before the leak developed or the polymer that is injected after the leak is fixed. Of course, the polymer that is injected while the leak is active will be susceptible to oxidative degradation. Maintaining dissolved oxygen at undetectable levels is necessary to maximize polymer stability. This can be accomplished readily without the use of chemical oxygen scavengers or antioxidants.
Incremental-Oil Success From Waterflood Sweep Improvement in Alaska
Authors: Ohms Danielle , McLeod Jennifer , Graff Craig J. , Frampton Harry , Morgan Jim C. , Cheung Stephen , Chang K.T.. T.
Published: June 2010

Waterflood thief zones in communication with the rest of the reservoir are a severe and previously challenging problem. This paper gives an introduction to the nature of a novel, heat-activated polymer particulate. Details are presented of a trial of this in-depth diversion system, resulting in commercially significant incremental oil from a BP Alaskan field. The system of one injector and two producers was selected because of a high water/oil ratio and low recovery factor, which was recognized as an indicator of the presence of an injection-water thief zone and was confirmed by study of a previous injection survey. The area around the wells is bounded by faults, so the system can be considered to be isolated from surrounding wells and operations. The position of the thermal front in the reservoir, tracer transit times, injection rates, and interwell separations indicated that the slowest reacting of the three commercial grades available was most appropriate for the trial.

The treatment was designed using laboratory tests and numerical simulation informed by pressure and chemical-tracer tests. Long- sandpack tests indicated permeability-reduction factors of 11 to 350 for concentrations of 1,500 to 3,500 ppm active particles in sand of 560- to 670-md permeability at 149°F. 15,587 gal of particulate product was dispersed using 8,060 gallons of dispersing surfactant, into 38,000 bbl of injected water, and was pumped over a period of 3 weeks at a concentration of 3,300 ppm active particles.

Placement deep in the reservoir between injector and producer was confirmed by pressure-falloff analysis and injectivity tests. The incremental oil predicted from the simulation was 50,000 to 250,000 bbl over 10 years. In fact, more than 60,000 bbl of oil was recovered in the first 4 years at a cost comparable with that of traditional well work and less than that of sidetracking.
Formation-Damage and Well-Productivity Simulation
Authors: Lohne Arild , Han Liqun , Zwaag Claas van , van Velzen Hans , Mathisen Anne-Mette , Twynam Allan , Hendriks Wim , Bulgachev Roman , Hatzignatiou Dimitrios G.
Published: June 2010

In this paper, we describe a simulation model for computing the damage imposed on the formation during overbalanced drilling. The main parts modeled are filter-cake buildup under both static and dynamic conditions; fluid loss to the formation; transport of solids and polymers inside the formation, including effects of porelining retention and pore-throat plugging; and salinity effects on fines stability and clay swelling. The developed model can handle multicomponent water-based-mud systems at both the core scale (linear model) and the field scale (2D radial model). Among the computed results are fluid loss vs. time, internal damage distribution, and productivity calculations for both the entire well and individual sections.

The simulation model works, in part, independently of fluid-loss experiments (e.g., the model does not use fluid-leakoff coefficients but instead computes the filter-cake buildup and its flow resistance from properties ascribed to the individual components in the mud). Some of these properties can be measured directly, such as particle-size distribution of solids, effect of polymers on fluid viscosity, and formation permeability and porosity. Other properties, which must be determined by tuning the results of the numerical model against fluid-loss experiments, are still assumed to be rather case independent, and, once determined, they can be used in simulations at altered conditions as well as with different mud formulations. A detailed description of the filter-cake model is given in this paper.

We present simulations of several static and dynamic fluid-loss experiments. The particle-transport model is used to simulate a dilute particle-injection experiment taken from the literature. Finally, we demonstrate the model's applicability at the field scale and present computational results from an actual well drilled in the North Sea. These results are analyzed, and it is concluded that the potential effects of the mechanistic modeling approach used are (a) increased understanding of damage mechanisms, (b) improved design of experiments used in the selection process, and (c) better predictions at the well scale. This allows for a more-efficient and more-realistic prescreening of drilling fluids than traditional core-plug testing.
Gas-Well Liquid-Loading-Field-Data Analysis and Multiphase-Flow Modeling
Authors: Veeken Kees , Hu Bin , Schiferli Wouter
Published: June 2010

Gas-well liquid loading occurs when gas production becomes insufficient to lift the associated liquids to surface. When that happens, gas production becomes intermittent and eventually stops. In depleting gas reservoirs, the technical abandonment pressure and ultimate recovery are typically governed by liquid loading. To date, most methods for predicting liquid loading have followed Turner et al. (1969), who describe liquid loading as the point where the liquid droplets suspended in the gas flow start moving downward rather than upward. This paper presents (offshore) liquid-loading field data that exceed the Turner predicted values by an average of 40%, and analyzes the sensitivity of the liquid-loading gas rate for different well parameters. It subsequently presents the results of steady-state and transient multiphase-flow modeling, carried out to identify the influence of the same well parameters. A modified Turner expression is proposed that best fits the liquid-loading field data and broadly agrees with the results of a multiphase-flow model that uses a modified version of the Gray outflow correlation. The results of transient-flow modeling support the flow-loop observation that liquid loading occurs because of liquid-film-flow reversal rather than droplet-flow reversal. The impact of these findings on gas-well deliquefication is explored.
IO Design Gives High Efficiency
Authors: Moltu Berit , Nærheim Jakob
Published: June 2010

Integrated operations (IO) is about employing real-time data and new technology to remove barriers between disciplines, expert groups, locations, and companies. In this paper, we investigate the effect on efficiency from design and work practice in operations support (OPS) rooms. A study taken within a Norwegian oil and gas company shows an evident correlation between IO design and high efficiency.

This study shows the difference in design and practice between four different OPS rooms. The OPS unit is supposed to support interaction between different locations (e.g., onshore and offshore) in the upstream oil industry. Recent practice has established special OPS rooms to make operations and maintenance work more feasible between the onshore-based operation unit and the offshore operations.

In this study, newer academic perspectives from science and technology studies (STSs) are taken into the field of health, safety, and environment (HSE). Inspired by actor network theory (Latour 1987, 1999), the OPS rooms are seen as a chain of networks between different physical locations, different information and communication technology (ICT) solutions, different organizational and managerial models, and new working practices, all intended to support the current operations. The IO solution is intended to support and create new ways of working based on real-time data and online communication, and across geographic space. This improves transparency in solutions (e.g., to open up frozen borders between different departments, different disciplines, different geographical locations, and between management and employers, and to foster new perspectives on ICT and on what a room is).

The variety of solutions and practices was studied by participative observation in all five rooms. More than 40 employees working with OPS onshore and offshore were interviewed. A survey was conducted on efficiency of operations and maintenance work, optimization of production, and management of asset integrity and technical disciplines. Analyses of the results on efficiency concluded that the highest-IO-maturity assets perform well when it comes to efficiency. We attribute this to a more-online and -proactive work practice. The asset with the highest IO maturity reports a good work environment where it is enjoyable to work. We also attribute this to the transparency in solutions.
Creating Efficient Portfolios That Match Competing Corporate Strategies
Authors: Willigers B.J.A.. J.A. , Majou F..
Published: June 2010

The process of portfolio optimization provides guidance to decision makers on how to manage an asset base given corporate objectives, market conditions, and organizational capability. Many applications in the oil and gas industry are based upon Markowitz's (1952) efficient-portfolio theory. In the standard implementation of this framework, an efficient portfolio is defined as one that yields the highest value given a specific degree of risk.

A corporate decision maker will aim, however, to select a portfolio that meets several often-competing objectives (i.e., maximize portfolio value while minimizing capital expenditure). The optimal portfolio choice given one constraint is typically not optimal given one of the competing constraints. This requires the portfolio manager to identify and select those portfolios that best meet all corporate constraints. Deciding which portfolio to develop is often compounded by there being several portfolios having similar economic characteristics. However, these portfolios can generally be differentiated by strategy, which may depend on nonfinancial attributes such as the geographic location of the assets or on geological settings that might require different engineering expertise.

In this study, a large set of exploration portfolios and their attributes have been simulated. Through applying a series of simple and transparent filters, a few portfolios can be identified that meet all the corporate constraints. After a shortlist has been created, the portfolios can easily be characterized by strategy, and the tradeoffs between them can be assessed.
Partitioning of Bitumen-Solvent Systems Into Multiple Liquid Phases
Authors: Jossy C. , Frauenfeld T. , Rajan V.
Published: June 2010

Both gravity-based and cyclic processes for heavy oil/bitumen recovery may involve the use of hydrocarbon (n-alkane) solvent at relatively high solvent/oil ratios. Previous work at ARC has shown that at high solvent loadings, the oil/solvent mixture partitions into a solvent-rich oil phase and a heavy-ends-rich (mostly asphaltene) oil phase. The liquid phases have significantly different densities and viscosities. The partitioning phenomenon could have a significant impact on the performance of gravity-based processes such as Vapex involving solvents, where the low-viscosity liquid phase carries the bulk of the oil production, and the heavier liquid phase consisting of mostly asphaltene is essentially immobile. The solvent-rich phase will consist of the upgraded (de-asphalted) oil. Production of upgraded oil thus would not only enhance the production rate, but also have both economic and pipelining advantages. Data on the physical properties (viscosity and density) and the composition of both the partitioned phases are needed to design and optimize solvent-based processes in reservoir engineering calculations.

Phase partitioning experiments conducted at the Alberta Research Council Laboratories along with the experimental data are presented in this paper.

Introduction

Both gravity-based and cyclic processes for heavy oil recovery may involve the use of solvent which dissolves in heavy oil or bitumen at relatively high solvent/oil ratios. Earlier works at ARC, and recent work in the Thermal Gravity Strategic area, have shown that at high loadings the oil/solvent mixture partitions into a solvent- rich oil phase and a heavy-ends-rich oil phase. The two liquid oleic phases have significantly different densities and viscosities. The phase partitioning may have significant impact on the performance of a solvent-based heavy oil recovery process. In particular, VAPEX and other gravity-based processes involving solvents may have their performance enhanced if the low-viscosity phase carries the bulk of the oil production, and the heavy-ends-rich phase contains most of the asphaltene and is essentially immobile.
Unlocking Bitumen in Thin and/or Lower Pressure Pay Using Cross SAGD (XSAGD)
Authors: Stalder J.L.
Published: June 2010

Cross SAGD (XSAGD) is similar to SAGD except that the horizontal injection wells are placed perpendicular to the horizontal production wells. Some completion restriction near the points where the wells cross can be included in the initial well completions or added later to limit short-circuiting of steam between the wells. The concept of XSAGD as applied in a 20-metrethick homogeneous sand was introduced in the November 2005 International Thermal Operations and Heavy Oil Symposium in Calgary, Alberta. Expanding beyond that presentation, this paper describes simulations showing that XSAGD offers advantages over SAGD for developing thin and/or low-pressured bitumen sands. By combining both gravity drainage and lateral displacement, XSAGD can accelerate recovery, reduce steam requirements and improve economic potential compared to SAGD. Simulation results are discussed comparing SAGD and XSAGD performance for pay thickness from 10 - 40 metres, for pressures ranging from 1,500 - 4,500 kPa, and for homogeneous and heterogeneous pay.

Introduction

An earlier study(1) describes how XSAGD combines lateral displacement with gravity drainage to accelerate bitumen recovery compared to the SAGD(2) concept in a 20-m homogeneous sand. Some form of completion restriction near where the injection and production wells cross is necessary to limit short-circuiting of the steam and to promote lateral displacement. This restriction could be added after initial communication is established between the wells or it could be built in from the beginning. The recovery acceleration for XSAGD is partially related to the increased drawdown that can be applied to the producing wells while still maintaining effective steam-trap control. This benefit is due to the lateral offset between the active sections of the completions and the tendency for steam to gravity-override before reaching the unrestricted sections of the producing wells. Overall, XSAGD accelerates bitumen recovery and lateral expansion of the steam chamber and reduces cumulative steam oil ratio (CSOR) compared to SAGD. However, XSAGD recovery factor (RF) generally is slightly lower than SAGD RF. The capital costs for wells, pads and facilities should be essentially the same for both processes even though the pad arrangement may be somewhat less flexible for XSAGD.
Dynamic Modelling of Solution-Gas Drive in Heavy Oils
Authors: Shahvali M. , Pooladi-Darvish M.
Published: June 2010

Some heavy oil reservoirs in Canada show atypically high production rates and high primary oil recoveries under solution-gas drive. Much attention has been given to the anomalous behaviour observed in such heavy oil reservoirs, and several models have been suggested to explain these anomalies.

There are two classes of effects responsible for the unusual behaviour of solution-gas drive in heavy oil reservoirs, including fluid effects and rock/geomechanical effects. This study focuses exclusively on fluid effects.

In at least two ways, solution-gas drive in heavy oils differs from that in light oils. In heavy oils, the concentration of gas in the oil can be significantly greater than the equilibrium value; the oil could be significantly supersaturated. Additionally in heavy oils, recovery and gas mobility show rate dependent behaviour. Both of these effects are taken into consideration in this study.

In this paper, we develop a dynamic model that captures many important processes that affect heavy oil recovery. The non-equilibrium early time behaviour is modelled by introducing a kinetic equation describing the rate of evolution of solution gas into free gas. The equation is derived based on a phenomenological analysis which takes into account bubble nucleation and growth. A second component of this model captures the low gas mobility in heavy oil reservoirs and its dependency on viscous forces. To account for the effect of viscous forces on gas mobility, relative permeability functions are introduced that not only depend on gas saturation but also on local oil phase velocity and viscosity.

While many of the previous models apply several kinetic equations associated with a large number of parameters, we have shown that the modifications suggested in this study enable predicting many of the unusual behaviours observed in solution-gas drive in heavy oil reservoirs, using only one kinetic equation with a smaller number of fitting parameters.
Shale Swelling, Osmosis, and Acoustic Changes Measured Under Simulated Downhole Condition
Authors: Ewy R.T.. T. , Stankovic R.J.. J.
Published: June 2010

Preserved shale samples from four different shale cores were exposed to various aqueous fluids while under simulated downhole stress conditions. Before fluid exposure, the samples were not contacted by any aqueous fluid, including simulated pore fluid. Time-dependent measurements of pore pressure, swelling, and acoustic velocities were made. Pore pressures both less than and greater than the applied fluid pressure were observed, and apparent osmotic membrane efficiencies were calculated. Swelling was found to depend not only on the shale type and the fluid but also on the level of confining stress; sufficient confining stress can prevent swelling. Swelling anisotropy was observed. Acoustic velocities were found to change as a result of fluid exposure, but significant velocity decrease occurred only in the presence of chemically induced swelling. S-wave velocities were found to be more sensitive than P-wave velocities. Because swelling is expected to occur mostly in the radial direction around a wellbore and only very close to the wellbore, the best detection method would be either (1) well-parallel S-velocities processed to yield the high-frequency (near-wellbore) slowness or (2) S-velocities measured in the radial direction instead of the well-parallel direction.
Development and Characterization of Extruded Product Using Carrot Pomace and Rice Flour
Authors: Kumar Navneet , Sarkar B. C. , Sharma Harish Kumar
Published: June 2010

Dehydrated carrot pomace was added in different proportions (10-30%) to rice flour. The formulation was extruded at different moisture content (17-21%), screw speed (270-310 rpm) and die temperature (110-130°C). The experimental combinations were decided based on central composite rotatable design for four variables at five levels of each variable. The lateral expansion, bulk density, water absorption index, water solubility index, hardness and sensory characteristics were measured as responses. Significant regression models were established with the coefficient of determination, R² greater than 0.70. The results indicated that pomace proportion, screw speed and temperature significantly influenced (P<0.10) lateral expansion; moisture content and screw speed for bulk density; pomace proportion and temperature for water absorption index and water solubility index, pomace proportion, screw speed and temperature for hardness and screw speed for sensory score. The compromised optimum condition obtained by numerical integration for development of extrudates were: carrot pomace of 11.75% in rice flour, moisture content 19.92%, screw speed 249.1 rpm and die temperature 114.3°C. Sensory evaluation revealed that carrot pomace could be incorporated into ready-to-eat expanded products upto the level of 11.75%.
Synthesis and characterization of ammonium phosphate fertilizers with boron
Authors: Magda Angela , Pode Rodica , Muntean Cornelia , Medeleanu Mihai , Popa Alexandru
Published: June 2010

The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w) were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500?C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500?C, an increase of thermal stability with an increase of the boron content was observed. X-ray diffraction of a heat-treated sample containing 5 % (w/w) boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500?C, which explains the increase in thermal stability.
Comparison of decompressive surgery, electroacupuncture, and decompressive surgery followed by electroacupuncture for the treatment of dogs with intervertebral disk disease with long-standing severe neurologic deficits
Authors: Joaquim Jean G. F. , Luna Stelio P. L. , Brondani Juliana T. , Torelli Sandra R. , Rahal Sheila C. , de Paula Freitas Fernando
Published: June 2010

Objective—To compare the effects of decompressive surgery (DSX), electroacupuncture (EAP), and DSX followed by EAP (DSX + EAP) for the treatment of thoracolumbar intervertebral disk disease (IVDD) in dogs with severe neurologic deficits of > 48 hours' duration.

Design—Retrospective case series and prospective clinical trial.

Animals—40 dogs between 3 and 6 years old and weighing between 10 and 20 kg (22 and 44 lb) with long-standing (> 48 hours) clinical signs of severe neurologic disease attributable to thoracolumbar IVDD.

Procedures—Thoracolumbar medullar injury was classified on the basis of neurologic signs by use of a scale ranging from 1 (least severe) to 5 (most severe). The DSX dogs (n = 10) were retrospectively selected from those that underwent DSX for the treatment of thoracolumbar IVDD. In addition, 19 dogs received EAP alone and 11 dogs underwent DSX followed by EAP (DSX + EAP). Outcome was considered a clinical success when a dog initially classified as grade 4 or 5 was classified as grade 1 or 2 within 6 months after the end of treatment.

Results—The proportion of dogs with clinical success was significantly higher for dogs that underwent EAP (15/19) than for dogs that underwent DSX (4/10); the proportion of dogs with clinical success for dogs that underwent DSX + EAP was intermediate (8/11).

Conclusions and Clinical Relevance—EAP was more effective than DSX for recovery of ambulation and improvement in neurologic deficits in dogs with long-standing severe deficits attributable to thoracolumbar IVDD.
Natural glufosinate resistance of soil microorganisms and GMO safety
Authors: Tothova Timea , Sobekova Anna , Holovska Katarina , Legath Jaroslav , Pristas Peter , Javorsky Peter
Published: June 2010

Bacteria and fungi from pristine soil, never exposed to glufosinate herbicide, were isolated and analyzed for glufosinate tolerance. Seven of the 15 tested isolates were sensitive to 1 mM glufosinate (an active ingredient of many nonselective contact herbicides), 5 were resistant to 4 mM glufosinate and 3 even to 8 mM glufosinate in liquid medium. None of the isolated microorganisms carried the gene for glufosinate resistance bar (bialaphos resistance) in its genome and at least in some of glufosinate-resistant isolates the increased glutamine synthetase level was detected as a possible resistance mechanism. The transfer of the bar glufosinate resistance gene from transgenic maize Bt 176 into glufosinate-sensitive soil bacterium Bacillus pumilus S1 was not detected under the laboratory conditions by a classical plate count method and PCR. The ecological risk of potential bar gene transfer from genetically modified plants into soil microcosms under natural circumstances is discussed.
Ötzi, the Iceman and his Leather Clothes
Authors: Püntener Alois G. , Moss Serge
Published: June 2010

Over 5000 years ago, a man climbed up to the icy heights of the glacier in South Tyrol, Italy and died. He was found by accident in 1991, with his clothes and equipment, mummified and frozen: an archaeological sensation and a unique snapshot of a Copper Age man. For several years highly
specialised research teams have examined the mummy and all accompanying items. This paper describes how fur and leather clothes of the iceman could have been tanned. Details of the analytical tests undertaken on the 5000 year old leather samples and what they revealed are presented.
Noninvasive detection of the distinction between progressive and compensated hydrocephalus in infants: is it possible?
Authors: Leliefeld Paul H. , Gooskens Rob H. J. M. , Tulleken Cees A. F. , Regli Luca , Uiterwaal Cuno S. P. M. , Han K. Sen , Kappelle L. Jaap
Published: June 2010

Object

Clinical signs and symptoms of hydrocephalus can be clear and specific, but also subtle, nonspecific, or even absent. It may be difficult to decide whether shunt placement is indicated, especially in infants. Therefore, there is a need for the development of better noninvasive detection methods to distinguish between compensated and (slowly) progressive hydrocephalus. Early interference can reverse the cerebral damage, whereas the detection of a nonpathological state in infants with compensated hydrocephalus avoids the complications of unnecessary shunt procedures. Using MR imaging, the authors investigated cerebral blood flow (CBF) and apparent diffusion coefficients (ADCs) measured in infants with clinically compensated hydrocephalus.

Methods

The diagnosis of compensated hydrocephalus was made on the basis of clinical criteria, consisting of no signs or symptoms of increased intracranial pressure (ICP), measurement of a normal ICP, and standard MR imaging showing enlarged ventricles. Flow measurements through both internal carotid arteries and the basilar artery were considered to represent the total CBF. In addition, ADC values were assessed in 5 different regions of interest in the brain parenchyma using diffusion weighted imaging. Brain volumetric measurement was performed to express CBF in ml/100 cm3 brain/min, thus compensating for physiological CBF growth over time. Mean arterial blood pressure was manually measured to exclude this factor as a cause of a possible change in CBF. Intracranial pressure measurement was performed noninvasively using the Rotterdam Teletransducer.

Results

Eighteen infants with clinically compensated hydrocephalus were included. The mean CBF was 53.5 ml/100 cm3 of brain/min. The individual CBF values were graphically compared with age-related normal CBF values and fell in the normal range. Mean ADC value was 890.0 ×10−6 mm2/sec. Apparent diffusion coefficient values per region of interest were graphically compared with normal ADC values per region of interest and fell within the normal range.

Conclusions

In infants with hydrocephalus, normal CBF and low ADC values, as measured using MR imaging, are associated with compensated hydrocephalus and may support a conservative approach with respect to the decision on whether to place a shunt.
Vagus nerve stimulation therapy in patients with autism spectrum disorder and intractable epilepsy: results from the vagus nerve stimulation therapy patient outcome registry
Authors: Levy Michael L. , Levy Karen M. , Hoff Dayna , Amar Arun Paul , Park Min S. , Conklin Jordan M. , Baird Lissa , Apuzzo Michael L. J.
Published: June 2010

Object

The purpose of this study was to determine the effectiveness of vagus nerve stimulation (VNS) therapy on quality-of-life (QOL) variables among patients with both autism spectrum disorder (ASD) and persistent or recurrent intractable epilepsy.

Methods

Data were obtained from the VNS therapy patient outcome registry, which was established after US FDA approval of the VNS device in 1997 as a means of capturing open-label clinical data outside of protocol. The integrity of the systems for collecting and processing registry data was authenticated by an independent auditing agency. The effect of potential selection bias, however, remains uncertain.

Results

Two cohorts were compared: 1) patients with epilepsy but without ASD (non-ASD [NASD] Group, 315 patients) who were being tracked in the registry (this cohort, which was controlled for age, included patients 20 years of age or younger); and 2) patients with a diagnosis of ASD who underwent implantation of the VNS device (ASD Group, 77 patients). Differences between the ASD and NASD groups were noted in the following categories: sex (male preponderance in ASD); normal imaging results (MR imaging results normal in ASD); depression (less common in ASD); behavioral problems (more common in ASD); neurological deficit (more common in ASD); mental retardation (more common in ASD); and developmental delay. The only QOL difference between the ASD and NASD groups was noted in mood at 12 months postimplant (mood was improved in ASD) (p = 0.04). There were no other differences in the QOL variables.

Conclusions

Patients with ASD and intractable epilepsy respond as favorably as all other patients receiving VNS therapy. In addition, they may experience a number of QOL improvements, some of which exceed those classically observed following placement of a VNS device.
Glaciological investigations on Union Glacier, Ellsworth Mountains, West Antarctica
Authors: Rivera Andrés , Zamora R. , Rada Camilo , Walton Jonathan , Proctor Stuart
Published: June 2010

Union Glacier, West Antarctica, was intensively mapped in December 2008, when an over-snow traverse was conducted by CECS and ALE, with the aim to determine the ice-dynamical characteristics of the glacier, through mapping the crevasse fields and by providing a glaciological baseline for future studies. A mean ice thickness of 1450 m was measured, confirming the presence of a deep subglacial topography (∼900 m below sea level), much deeper than previously estimated. Ice velocities were also measured at 21 stakes drilled into the ice at the narrowest gate of the glacier between December 2007 and December 2008, yielding a mean value of 22.6 m a−1. These velocities, combined with the measured ice thicknesses and a numerical model, yielded an ice flux of 0.10 ±0.03 km3 a−1 w.e. Considering the ice basin above this gate, a mean surface mass balance of 0.18 ± 0.05 m a−1 was estimated, a value consistent with a mean snow accumulation for nearby ice streams. These values indicate that the glacier is at present near equilibrium.
Reinventing Diagnostics for Personalized Therapy in Oncology
Authors: Banerjee Diponkar
Published: June 2010

Human cancers are still diagnosed and classified using the light microscope. The criteria are based upon morphologic observations by pathologists and tend to be subject to interobserver variation. In preoperative biopsies of non-small cell lung cancers, the diagnostic concordance, even amongst experienced pulmonary pathologists, is no better than a coin-toss. Only 25% of cancer patients, on average, benefit from therapy as most therapies do not account for individual factors that influence response or outcome. Unsuccessful first line therapy costs Canada CAN$1.2 billion for the top 14 cancer types, and this extrapolates to $90 billion globally. The availability of accurate drug selection for personalized therapy could better allocate these precious resources to the right therapies. This wasteful situation is beginning to change with the completion of the human genome sequencing project and with the increasing availability of targeted therapies. Both factors are giving rise to attempts to correlate tumor characteristics and response to specific adjuvant and neoadjuvant therapies. Static cancer classification and grading systems need to be replaced by functional classification systems that not only account for intra- and inter- tumor heterogeneity, but which also allow for the selection of the correct chemotherapeutic compounds for the individual patient. In this review, the examples of lung and breast cancer are used to illustrate the issues to be addressed in the coming years, as well as the emerging technologies that have great promise in enabling personalized therapy.
Evaluation of Pyridoacridine Alkaloids in a Zebrafish Phenotypic Assay
Authors: Wei Xiaomei , Bugni Tim S. , Harper Mary Kay , Sandoval Imelda T. , Manos Elizabeth J. , Swift Jennifer , Van Wagoner Ryan M. , Jones David A. , Ireland Chris M.
Published: June 2010

Three new minor components, the pyridoacridine alkaloids 1-hydroxy-deoxyamphimedine (1), 3-hydroxy-deoxyamphimedine (2), debromopetrosamine (3), and three known compounds, amphimedine (4), neoamphimedine (5) and deoxyamphimedine (6), have been isolated from the sponge Xestospongia cf. carbonaria, collected in Palau. Structures were assigned on the basis of extensive 1D and 2D NMR studies as well as analysis by HRESIMS. Compounds 1–6 were evaluated in a zebrafish phenotype-based assay. Amphimedine (4) was the only compound that caused a phenotype in zebrafish embryos at 30 µM. No phenotype other than death was observed for compounds 1–3, 5, 6.
Micronutrients, N-Acetyl Cysteine, Probiotics and Prebiotics, a Review of Effectiveness in Reducing HIV Progression
Authors: Hummelen Ruben , Hemsworth Jaimie , Reid Gregor
Published: June 2010

Low serum concentrations of micronutrients, intestinal abnormalities, and an inflammatory state have been associated with HIV progression. These may be ameliorated by micronutrients, N-acetyl cysteine, probiotics, and prebiotics. This review aims to integrate the evidence from clinical trials of these interventions on the progression of HIV. Vitamin B, C, E, and folic acid have been shown to delay the progression of HIV. Supplementation with selenium, N-acetyl cysteine, probiotics, and prebiotics has considerable potential, but the evidence needs to be further substantiated. Vitamin A, iron, and zinc have been associated with adverse effects and caution is warranted for their use.
Induction of Drug Transporters Alters Disposition of Risperidone - A Study in Mice
Authors: Holthoewer David , Hiemke Christoph , Schmitt Ulrich
Published: June 2010

Pharmacokinetic interactions, e.g. modulation of drug transporters like P-glycoprotein at the blood-brain barrier, can be a reason for treatment non-response. This study focuses on the influence of induction of drug transporters on the disposition of the antipsychotic drugs risperidone and 9-hydroxyrisperidone. Brain and serum concentrations of risperidone and its active metabolite 9-hydroxyrisperidone, which are known P-glycoprotein substrates, were measured after drug transporter induction with rifampicin, dexamethasone or 5-pregnene-3beta-ol-20-on-16alpha-carbonitrile using high performance liquid chromatography. Disposition of risperidone and 9-hydroxyrisperidone was dramatically decreased in mouse brain and serum after drug transporter induction. The metabolism of risperidone was also affected.
Changes in Croplands as a Result of Large Scale Mining and the Associated Impact on Food Security Studied Using Time-Series Landsat Images
Authors: Matejicek Lubos , Kopackova Veronika
Published: June 2010

Geographic information systems and satellite remote sensing information are emerging technologies in land-cover change assessment. They now provide an opportunity to gain insights into land-cover change properties through the spatio-temporal data capture over several decades. The time series of Landsat images covering the 1985–2009 period is used here to explore the impacts of surface mining and reclamation, which constitute a dominant force in land-cover changes in the northwestern regions of the Czech Republic. Advanced quantification of the extent of mining activities is important for assessing how these land-cover changes affect ecosystem services such as croplands. The images employed from 1985, 1988, 1990, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, and 2009 assist in mapping the extent of surface mines and mine reclamation for large surface mines in a few selected areas of interest. The image processing techniques are based on pixel-by-pixel calculation of the vegetation index, such as NDVI. The NDVI values are classified into the defined classes based on CORINE Land Cover 2000 data in a 3280 km2 strip of Landsat images. This distribution of NDVI values is used to estimate the land-cover classes in the local areas of interest (184 km2, 368 km2, 737 km2, and 1,474 km2). Thus, the approximate land-cover stability of the 3,280 km2 strip during the whole 1985–2009 period is used to explore land-cover disturbances in the local areas of surface mines. In the case of NDVI, it also includes variations, presumably caused by seasonal vegetation effects, and local meteorological conditions. However, the main trends related to mining activities during the long-term period can be clearly understood. As a result, other objectives can be explored in the 1985–2009 period, such as cropland changes to other land use classes, changes of cropland patterns, and their impacts on food security. The presented spatio-temporal modeling based on long time series from 12 satellite images provides considerable experience for processing NDVI in the framework of identification of land-cover classes and also, to a certain degree, cropland variability with its impact on food security.
Comparison of Area-Based and Individual Tree-Based Methods for Predicting Plot-Level Forest Attributes
Authors: Yu Xiaowei , Hyyppä Juha , Holopainen Markus , Vastaranta Mikko
Published: June 2010

Approaches to deriving forest information from laser scanner data have generally made use of two methods: the area-based and individual tree-based approaches. In this paper, these two methods were evaluated and compared for their abilities to predict forest attributes at the plot level using the same datasets. Airborne laser scanner data were collected over the Evo forest area, southern Finland, with an averaging point density of 2.6 points/m2. Mean height, mean diameter and volume were predicted from laser-derived features for plots (area-based method) or tree height, diameter at breast height and volume for individual trees (individual tree-based method) using random forests technique. To evaluate and compare the two forest inventory methods, the root-mean-squared error (RMSE) and correlation coefficient (R) between the predicted and observed plot-level values were computed. The results indicated that both area-based method (with an RMSE of 6.42% for mean height, 10.32% for mean diameter and 20.90% for volume) and individual tree-based method (with an RMSE of 5.69% for mean height, 10.77% for mean diameter and 18.55% for volume) produced promising and compatible results. Increase in point density is expected to increase the accuracy of the individual tree-based technique more than that of the area-based technique.
Interpreting Sustainability for Urban Forests
Authors: Ordóñez Camilo , Duinker Peter N.
Published: June 2010

Incisive interpretations of urban-forest sustainability are important in furthering our understanding of how to sustain the myriad values associated with urban forests. Our analysis of earlier interpretations reveals conceptual gaps. These interpretations are attached to restrictive definitions of a sustainable urban forest and limited to a rather mechanical view of maintaining the biophysical structure of trees. The probing of three conceptual domains (urban forest concepts, sustainable development, and sustainable forest management) leads to a broader interpretation of urban-forest sustainability as the process of sustaining urban forest values through time and across space. We propose that values—and not services, benefits, functions or goods—is a superior concept to refer to what is to be sustained in and by an urban forest.
On the Chinese Carbon Reduction Target
Authors: Uwasu Michinori , Jiang Yi , Saijo Tatsuyoshi
Published: June 2010

In November 2009, China pledged a 40–45% decrease in CO2 emissions per GDP by 2020, as compared with the 2005 level. Although carbon intensity (emission) targets by nature are ambiguous, this study demonstrates that China’s pledge is consistent with the current Chinese domestic agenda that simultaneously pursues economic growth and energy security. The target numbers in the pledge seem reasonable, given the technological feasibility and measures, considered along with the assumption that moderate economic growth will occur. However, the study also argues that financial and institutional constraints exist as potential obstacles to achieving the target if the trend of the current economic tendencies continues.
T Cell Polarization at the Virological Synapse
Authors: Jolly Clare
Published: June 2010

Cell-to-cell spread of HIV-1 between CD4+ T cells takes place at multimolecular structures called virological synapses. A defining feature of the virological synapse is polarization of viral assembly and budding at sites of T cell-T cell contact. Recent work is beginning to address how viral proteins are targeted to the virological synapse and the molecular mechanisms that regulate HIV-1 egress by cell-to-cell spread. This review discusses our current understanding of these processes and considers how T cell polarization during other forms of intercellular communication may provide insight into HIV-1 assembly and dissemination.