bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of HER-3 Expression in the Prediction of Clinical Outcome for Advanced Colorectal Cancer Patients Receiving Irinotecan and Cetuximab
Authors: Scartozzi Mario , Mandolesi Alessandra , Giampieri Riccardo , Bittoni Alessandro , Pierantoni Chiara , Zaniboni Alberto , Galizia Eva , Giustini Lucio , Silva Rosa Rita , Bisonni Renato , Berardi Rossana , Biscotti Tommasina , Biagetti Simona , Bearzi Italo , Cascinu Stefano
Published: January 2011

Learning Objectives:

After completing this course, the reader will be able to: Describe the relationship between HER-3 status and response to treatment with cetuximab and irinotecan in patients with advanced colorectal cancer and EGFR+ wild-type K-RAS mutation in this study.Evaluate data that support using HER-3 status as a predictive factor for anti-EGFR treatment response in patients with colorectal cancer.

CME This article is available for continuing medical education credit at CME.TheOncologist.com

Preclinical data suggested that, in the presence of human epidermal growth factor receptor (HER)-3–altered activation, colorectal cancer cells may escape anti–epidermal growth factor receptor (EGFR)-mediated cell death. HER-3 overexpression may then represent a key factor for resistance to anti-EGFR antibodies in colorectal cancer. The aim of our analysis was to investigate a possible correlation between HER-3 expression and clinical outcome in wild-type K-RAS advanced colorectal cancer patients receiving cetuximab and irinotecan.

We retrospectively analyzed immunoreactivity for HER-3 in wild-type K-RAS advanced colorectal cancer patients receiving irinotecan and cetuximab.

Eighty-four advanced wild-type K-RAS colorectal cancer patients were available for HER-3 analysis. Forty patients (48%) had a HER-3− colorectal tumor, whereas the remaining 44 cases (52%) were deemed HER-3+. In patients with HER-3− and HER-3+ tumors, we observed a partial response in 17 (42%) and eight (18%) patients respectively; progressive disease occurred in 11 (35%) and 26 (53%) patients with HER-3− and HER-3+ tumors, respectively (p = .003). The median progression-free survival time was 6.3 months in patients with HER-3− tumors and 2.8 months for those who had HER-3–overexpressing tumors (p < .0001). The median overall survival time was 13.6 months in patients showing HER-3− tumors and 10.5 months for those who had HER-3–expressing tumors (p = .01).

HER-3 proved to be a predictive factor for clinical outcome in wild-type K-RAS colorectal cancer patients treated with cetuximab. Combined HER-3 and K-RAS analysis may represent an effective strategy for better selection of responding colorectal cancer patients.
Systematic Review of Medical Treatment in Melanoma: Current Status and Future Prospects
Authors: Garbe Claus , Eigentler Thomas K. , Keilholz Ulrich , Hauschild Axel , Kirkwood John M.
Published: January 2011

The incidence of melanoma is increasing worldwide, and the prognosis for patients with high-risk or advanced metastatic melanoma remains poor despite advances in the field. Standard treatment for patients with thick (≥2.0 mm) primary melanoma with or without regional metastases to lymph nodes is surgery followed by adjuvant therapy or clinical trial enrollment. Adjuvant therapy with interferon-α and cancer vaccines is discussed in detail. Patients who progress to stage IV metastatic melanoma have a median survival of ≤1 year. Standard treatment with chemotherapy yields low response rates, of which few are durable. Cytokine therapy with IL-2 achieves durable benefits in a greater fraction, but it is accompanied by severe toxicities that require the patient to be hospitalized for support during treatment. A systematic literature review of treatments for advanced, metastatic disease was conducted to present the success of current treatments and the promise of those still in clinical development that may yield incremental improvements in the treatment of advanced, metastatic melanoma.
Visceral Fat Area as a New Independent Predictive Factor of Survival in Patients with Metastatic Renal Cell Carcinoma Treated with Antiangiogenic Agents
Authors: Ladoire Sylvain , Bonnetain Franck , Gauthier Mélanie , Zanetta Sylvie , Petit Jean Michel , Guiu Séverine , Kermarrec Isabelle , Mourey Eric , Michel Frederic , Krause Denis , Hillon Patrick , Cormier Luc , Ghiringhelli François , Guiu Boris
Published: January 2011

Purpose.

A better identification of patients who are more likely to benefit from vascular endothelial growth factor–targeted therapy is warranted in metastatic renal cell carcinoma (mRCC). As adipose tissue releases angiogenic factors, we determined whether parameters such as visceral fat area (VFA) were associated with outcome in these patients.

Experimental Design.

In 113 patients with mRCC who received antiangiogenic agents (bevacizumab, sunitinib, or sorafenib) (n = 64) or cytokines (n = 49) as first-line treatment, we used computed tomography to measure VFA and subcutaneous fat area (SFA). We evaluated associations linking body mass index (BMI), SFA, and VFA to time to progression (TTP) and overall survival (OS).

Results.

High SFA and VFA values were significantly associated with shorter TTP and OS. By multivariate analysis, high VFA was independently associated with shorter TTP and OS. These results were internally validated using bootstrap analysis. By contrast, VFA was not associated with survival in the cytokine group. In the whole population, interaction between VFA and treatment group was significant for TTP and OS, thereby confirming the results.

Conclusion.

Our study provides the first evidence that high VFA could be a predictive biomarker from shorter survival in patients given first-line antiangiogenic agents for mRCC.
Early Diagnosis of Medullary Thyroid Carcinoma: Is Systematic Calcitonin Screening Appropriate in Patients with Nodular Thyroid Disease?
Authors: Costante Giuseppe , Filetti Sebastiano
Published: January 2011

Learning Objectives

After completing this course, the reader will be able to: Compare guideline recommendations regarding the use of routine calcitonin screening to diagnose medullary thyroid carcinoma patients with clinical risk factors.Select patients for whom calcitonin screening for medullary thyroid carcinoma may be an appropriate diagnostic approach.

CME This article is available for continuing medical education credit at CME.TheOncologist.com

Because of its poor prognosis and high mortality rate, early diagnosis of medullary thyroid carcinoma (MTC) is a challenge. For almost two decades, routine serum calcitonin (CT) measurement has been used as a tool for early MTC diagnosis, with conflicting results. In 2006, the European Thyroid Association (ETA) recommended serum CT measurement in the initial workup of thyroid nodules, whereas the American Thyroid Association (ATA) declined to recommend for or against this approach.

In late 2009, the revised ATA guidelines were published, and in June 2010 the ETA released new guidelines for the diagnosis and management of thyroid nodules that had been drafted in collaboration with the American Association of Clinical Endocrinologists and with the Associazione Medici Endocrinologi, and the picture became even more complex. The ATA still takes no stand for or against screening but acknowledges that, if testing is done, a CT value >100 pg/ml should be considered suspicious and an indication for treatment. As for the ETA, it seems to have taken a step back from its 2006 position, and it now advocates CT screening only in the presence of clinical risk factors. These new positions are more cautious and less straightforward because prospective, randomized, large-scale, long-term trial data are lacking. Are such studies feasible? Can they solve the CT dilemma? In the absence of adequate evidence, selective aggressive case finding should be pursued to improve MTC prognosis.
Modeling Reservoir Temperature Transients and Reservoir-Parameter Estimation Constrained to the Model
Authors: Duru Obinna O. , Horne Roland N.
Published: January 2011

Permanent downhole gauges (PDGs) provide a continuous source of downhole pressure, temperature, and sometimes flow-rate data. Until recently, the measured temperature data have been largely ignored, although a close observation of the temperature measurements reveals a response to changes in flow rate and pressure. This suggests that the temperature measurements may be a useful source of reservoir information.

In this study, reservoir temperature-transient models were developed for single- and multiphase-fluid flows, as functions of formation parameters, fluid properties, and changes in flow rate and pressure. The pressure fields in oil- and gas-bearing formations are usually transient, and this gives rise to pressure/temperature effects appearing as temperature change. The magnitudes of these effects depend on the properties of the formation, flow geometry, time, and other factors and result in a reservoir temperature distribution that is changing in both space and time. In this study, these thermometric effects were modeled as convective, conductive, and transient phenomena with consideration for time and space dependencies. This mechanistic model included the Joule-Thomson effects resulting from fluid compressibility and viscous dissipation in the reservoir during fluid flow.

Because of the nature of the models, the semianalytical solution technique known as operator splitting was used to solve them, and the solutions were compared to synthetic and real temperature data. In addition, by matching the models to different temperature-transient histories obtained from PDGs, reservoir parameters such as average porosity, near-well permeabilities, saturation, and some thermal properties of the fluid and formation could be estimated. A key target of this work was to show that temperature measurements, often ignored, can be used to estimate reservoir parameters, as a complement to other more-conventional techniques.
History Matching Using the Ensemble Kalman Filter With Multiscale Parameterization: A Field Case Study
Authors: Zhang Yanfen , Oliver Dean S.
Published: January 2011

The increased use of optimization in reservoir management has placed greater demands on the application of history matching to produce models that not only reproduce the historical production behavior but also preserve geological realism and quantify forecast uncertainty. Geological complexity and limited access to the subsurface typically result in a large uncertainty in reservoir properties and forecasts. However, there is a systematic tendency to underestimate such uncertainty, especially when rock properties are modeled using Gaussian random fields. In this paper, we address one important source of uncertainty: the uncertainty in regional trends by introducing stochastic trend coefficients. The multiscale parameters including trend coefficients and heterogeneities can be estimated using the ensemble Kalman filter (EnKF) for history matching.

Multiscale heterogeneities are often important, especially in deepwater reservoirs, but are generally poorly represented in history matching. In this paper, we describe a method for representing and updating multiple scales of heterogeneity in the EnKF. We tested our method for updating these variables using production data from a deepwater field whose reservoir model has more than 200,000 unknown parameters. The match of reservoir simulator forecasts to real field data using a standard application of EnKF had not been entirely satisfactory because it was difficult to match the water cut of a main producer in the reservoir. None of the realizations of the reservoir exhibited water breakthrough using the standard parameterization method. By adding uncertainty in large-scale trends of reservoir properties, the ability to match the water cut and other production data was improved substantially.

The results indicate that an improvement in the generation of the initial ensemble and in the variables describing the property fields gives an improved history match with plausible geology. The multiscale parameterization of property fields reduces the tendency to underestimate uncertainty while still providing reservoir models that match data.
Field Applications of a Semianalytical Model of Multilateral Wells in Multilayer Reservoirs
Authors: Pan Yan , Kamal Medhat M. , Kikani Jitendra
Published: January 2011

Advanced drilling technology has been widely and successfully applied to construct multilateral wells in reservoirs. This paper presents several field applications of a generalized semianalytical segmented model accounting for multilateral-well systems in commingled layered reservoirs. Cases include a heavy-oil field, Al Rayyan oil field offshore Qatar, and Dos Cuadras field offshore California.

The model can predict the production performance under either constant-rate or constant-pressure conditions of a well system with any number of arbitrarily oriented laterals of any length and nonuniform formation damage. The reservoir layers, with different porosities, anisotropic permeabilities, and drainage areas, are noncommunicating except through the wellbore. The solution is valid for large reservoirs and when no-flow or constant-pressure boundaries affect the pressure behavior.

Results of applying this method in the field cases showed that the model enabled us to predict multilateral-well performance, to obtain information about reservoir connectivity, and to estimate well and reservoir properties in a multilayer system. Uncertainty caused by the large number of unknown parameters in such a complex system represents the main challenge in using this method. It is recommended to use other means together with pressure transient data to reduce the uncertainty.

The presented model and the lessons learned from the field applications provide engineers with a tool enabling the use of transient data collected from multilateral wells in multilayer systems for reservoir characterization and performance forecast.
An Integrated Workflow for Granitic-Basement-Reservoir Evaluation
Authors: Farag S.. , Mas C.. , Maizeret P.D.. D. , Li B.. , Van Hung Le
Published: January 2011

In recent years, energy companies in the Asia Pacific region have focused increasing attention on granitic basement reservoirs, following several new oil and gas discoveries in these complex reservoirs. However, accurate formation evaluation in fractured, crystalline, granitic reservoirs is notoriously difficult. Furthermore, relatively little research has been conducted to understand loggingtool response or pressure-transient behavior, or to develop suitable workflows for formation evaluation in these types of reservoirs. In this paper, we propose a method for integrating various openhole logs, production logs, and well-test data to better evaluate the reservoir potential of fractured granitic formations. Because the wells are either horizontal or highly deviated, this workflow also serves as a primary method of assessing the lateral extent of a reservoir. We include a case study from the region to illustrate the workflow. Image-log interpretation, advanced acoustic measurements, nuclear logs, and production logs with distributed local sensors are combined with well-test data to derive the best possible evaluation of the fracture network around the borehole and the degree of connectivity with the reservoir at large. We also discuss the advantages and limitations of the proposed workflow and set the stage for further work in this complex environment.
Planning and Procedures for the Initial Startup of Subsea Production Systems
Authors: Duhon H.J.. J. , Garduno J.L.. L. , Robinson N.A.. A.
Published: January 2011

Projects progress through phases of design, construction, installation, commissioning, initial startup, and operations. This paper addresses issues that arise at initial startup. Initial startup is defined here as the period when reservoir hydrocarbons are produced for the first time.

Initial startup of a subsea development is one of the most challenging periods in the operational life of the facility. Many issues complicate this period, including People issues. Many people from many teams are required to execute a startup; roles and responsibilities may be unclear and will change over the course of the startup; persons-onboard (POB) issues limit the number of people who can participate; personnel involved may not be fully trained in the operation of the facility.This will be the first time much or all of the equipment is used in live hydrocarbon service. Design flaws, commissioning omissions, and infant mortalities will reveal themselves.Preserving completion integrity requires low rates and slow bean-ups during initial startup because of high formation skin. Chokes designed for high rates and low pressure drops may not be capable of controlling the well at low rates. Also, topside systems designed for peak rates may not function well at low flow rates.Low flow rates and low initial temperatures result in hydrate risk, which may challenge the flow-assurance strategy.Completion and stimulation fluids returned during the initial well cleanup are corrosive and are difficult to treat. Typically, specialized water-treatment equipment is installed temporarily at topside to treat these fluids. The flowback fluids may also contain solids from the reservoir and from construction debris that may cause problems such as plugging small ports in control valves.Drilling, construction, installation, and commissioning activities [simultaneous operations (SIMOPS)] may still be in progress. The exact state of equipment items may be unclear and may change over the course of the startup.Reservoir engineers will seek to obtain reservoir information through well tests, especially pressure-buildup tests. Other data- collection efforts are important to validate the design and establish benchmarks.Some regulatory requirements apply specifically to the startup period.Special procedures are usually written for the initial startup. These will differ in important ways from the normal operating procedures. There is risk that there may be errors in the startup procedures, that operators may err in implementing the procedures, or that equipment designed for normal operation will not function well at the conditions imposed by the startup.Startup is one of the most hazardous periods in field life. Effective risk management is essential.

Careful planning is required to achieve a trouble-free startup. This paper describes the key requirements for generating effective initial-startup plans and procedures.
Simultaneous Interpretation of Pressure, Temperature, and Flow-Rate Data Using Bayesian Inversion Methods
Authors: Duru Obinna O. , Horne Roland N.
Published: January 2011

Current downhole measuring technologies have provided a means of acquiring downhole measurements of pressure, temperature, and sometimes flow-rate data. Jointly interpreting all three measurements provides a way to overcome data limitations that are associated with interpreting only two measurements—pressure and flow-rate data—as is currently done in pressure-transient analysis. This work shows how temperature measurements can be used to improve estimations in situations where lack of sufficient pressure or flow-rate data makes parameter estimation difficult or impossible.

The model that describes the temperature distribution in the reservoir lends itself to quasilinear approximations. This makes the model a candidate for Bayesian inversion. The model that describes the pressure distribution for a multirate flow system is also linear and a candidate for Bayesian inversion. These two conditions were exploited in this work to present a way to cointerpret pressure and temperature signals from a reservoir.

Specifically, the Bayesian methods were applied to the deconvolution of both pressure and temperature measurements. The deconvolution of the temperature measurements yielded a vector that is linearly related to the average flow-rate from the reservoir and, hence, could be used for flow-rate estimation, especially in situations in which flow-rate measurements are unavailable or unreliable. This flow rate was shown to be sufficient for a first estimation of the pressure kernel in the pressure-deconvolution problem.

When the appropriate regularization parameters are chosen, the Bayesian methods can be used to suppress fluctuations and noise in measurements while maintaining sufficient resolution of the estimates. This is the point of the application of the method to data denoising. In addition, because Bayesian statistics represent a state of knowledge, it is easier to incorporate certain information, such as breakpoints, that may help improve the structure of the estimates. The methods also lend themselves to formulations that make possible the estimation of initial properties, such as initial pressures.
Mechanics and Upscaling of Heavy Oil Bitumen Recovery by Steam-Over-Solvent Injection in Fractured Reservoirs Method
Authors: Singh Rajpreet , Babadagli Tayfun
Published: January 2011

Recently, the steam-over-solvent injection in fractured reservoirs (SOS-FR) method was proposed as a potential solution for efficient heavy-oil/bitumen recovery in oil-wet naturally fractured reservoirs. The method is based on initial injection steam (Phase 1), followed by solvent (Phase 2). In the third cycle (Phase 3), steam is injected again to recover more oil and retrieve the solvent. Solvent retrieval during the third cycle was observed to be fast if the temperature is at approximately the boiling point of the solvent. This process is controlled by efficient matrix recovery and the mechanics of the process need to be clarified to further determine the efficient application conditions for the given matrix and oil characteristics.

Single-matrix behaviour during the process was numerically modelled for static conditions and the results were matched with the experimental observations. The physics of the recovery mechanism was analyzed through visual inspection of saturation and concentration profiles in each cycle. The major observation was the substantial effect of gravity in oil recovery when the matrix were exposed to solvent. Special attention was given to the solvent retrieval rate and amount in Phase 3 and the permeability reduction caused by asphaltene precipitation in Phase 2. This phenomenon was modelled using a permeability function changing with spatial coordinates and time (i.e., k =f (x ,y ,z ,t ). It was observed that permeability reduction caused by asphaltene precipitation is significant and needs to be taken into account in the modelling process.

After showing the effect of the matrix size on the oil recovery and solvent retrieval, an upscaling analysis was performed. The log-log relationship between the time value to reach ultimate recovery and the matrix size yielded a straight-line relationship with a noninteger exponent less than two for all three phases of the process. The observed straight-line relationship (and the exponent values obtained) is highly encouraging to extend the study to obtain a universal scaling relationship.
Chemical Treatment To Mitigate Condensate and Water Blocking in Gas Wells in Carbonate Reservoirs
Authors: Ahmadi M. , Sharma M. M. , Pope G. A. , Torres D. E. , McCulley C. A. , Linnemeyer H.
Published: January 2011

Many gas wells suffer a loss in productivity because of liquid accumulation in the near-wellbore region. Chemical stimulation may be used as a remedy by altering the wettability to nonliquid wetting. Successful treatments decrease liquid trapping, increase fluids mobility, and improve the well's deliverability. This paper presents the first effective chemical treatment to mitigate liquid blocking in carbonate gas reservoirs. Screening tests were developed to quickly and effectively identify suitable chemicals from a large pool of compounds. X-ray photoelectron spectroscopy (XPS) measurements and drop-imbibition tests with water and n-decane were found to be necessary but not sufficient indicators of the effectiveness of the chemicals and were used as screening tests.

An integral part of the development of the treatment solution was the selection of a solvent mixture capable of delivering the fluorinated chemical to the rock surface. The treatment solution, mixture of chemical dissolved in solvent, must be stable in the presence of both brine and condensate so that it will not precipitate and will not reduce permeability of the rock. We acquired measured relative permeability values in Texas cream limestone (TCL) cores from high-pressure/high-temperature (HP/HT) coreflood experiments before and after treatment. Measurements were made using a pseudosteady-state method with a synthetic gas/condensate mixture. To enhance the durability of the treatment, a special amine primer is introduced. The gas relative permeability increased considerably (approximately 80%) after the treatment compared to that before treatment. This increase remained substantial, greater than 60% after injection of more than 1,000 pore volumes (PV) of gas/condensate mixture. We found an even greater increase in gas relative permeability during unsteady displacement of water by methane. The improvement remained after injecting 20 PV of brine and increasing the temperature in the treated core from 175 to 275°F.

The chemical treatment developed in this research can be applied to increase well deliverability of both gas and condensate in the field, providing that it is properly designed by considering key parameters such as reservoir pressure and temperature, brine salinity, and initial water saturation.
Two Issues in Wellbore Heat Flow Modelling Along With the Prediction of Casing Temperature in the Steam Injection Wells
Authors: Bahonar Mehdi , Azaiez Jalel , Chen Zhangxing
Published: January 2011

Although several models to determine the formation temperature in the modelling of thermal production and injection processes have already been suggested, there is no rigorous or systematic comparison between these models' predictions that can guide the choice of the most appropriate one. Another issue in thermal wellbore simulators is the commonly used assumption of semisteady-state heat transfer from the wellbore up to the cementing/formation interface. The effect of the semisteady-state assumption vs. the unsteady-state assumption for the heat transfer from the wellbore up to the formation has not received much attention in the literature and can be important in some cases.

The results of a detailed analysis of the two previously described issues can be implemented in all thermal wellbore and reservoir simulators to increase their accuracy.

The previously described stated issues will be addressed in the present work by developing a numerical nonisothermal two-phase wellbore simulator coupled with tubular and cement material and surrounding formation. The first issue will be studied in detail by comparing five different models for the formation temperature treatment (FTT) plugged in the developed thermal wellbore simulator.

Investigation of the second issue will be achieved by analyzing the three critical items: first, a 2D heat transfer PDE model of the formation is discretized in a general form; second, the gridding system is shifted from the formation toward the casing; and third, an effective specific heat capacity for the casing is used. The effects of choosing different models for FTT and using either the unsteady-state or the semisteady-state assumption in the heat loss from the wellbore up to the formation will be investigated. The model will be validated against field data to show its merits in predicting the casing temperature.

The entire wellbore system contains wellbore, tubing, insulation, annulus, casing, cementing and formation. A fundamental understanding of this system is still a challenging issue in the petroleum industry, and its accurate modelling and coupling with reservoirs has become increasingly significant as more energy resources are sought.
Numerical Study of Gas Evolution and Transport Behaviours in Natural Gas-Hydrate Reservoirs
Authors: Uddin Mafiz , Wright Fred , Coombe Dennis A.
Published: January 2011

Gas hydrates are a potentially vast untapped source of natural gas. Recent numerical and field studies suggest the Mallik gas-hydrate field in Canada's Mackenzie Delta may represent a technically producible and potentially economically viable reservoir of natural gas. Our initial reservoir simulations using a kinetic reaction approach indicate that gas evolution and transport within porous geologic reservoirs have a significant effect on fluid production characteristics, while field and laboratory data suggest that significant amounts of evolved gas can be trapped for some time within the reservoir, depending on the field operation.

In this work, we invoke modelling concepts extensively employed in quantifying gas ex-solution from viscous oils to further assess the kinetic behaviour of gas-hydrate ex-solution through depressurization. Here, the gas bubbles can be categorized into three groups with explicit transport behaviour: small bubbles (water phase), large bubbles (immobile) and connected bubbles (or free gas). These concepts allow the development of a new set of kinetic reactions for hydrate dissociation: one representing the (possibly delayed) conversion of hydrate into water and dispersed gas bubble phases, and one representing the evolution from dispersed bubbles to connected bubbles. These reactions can effectively capture the nonequilibrium fluid-flow behaviour observed in field production tests.

For modelling of the transport phenomenon, we assumed two explicit mobility formulations: (1) trapped bubbles (no mobility) and a flowing water phase and (2) large connected gas bubbles and flowing water (with relative mobility). Relative mobility can be estimated by using traditional gridblock-relative permeability curves. We then develop a simple mechanistic gas bubble trapping tool as a function of the capillary number, which can easily be incorporated into our numerical simulator. This entrapment of the nonwetting gas-phase results in higher values of critical gas saturation.

Two case studies based on alternative representations of a Mallik-like gas-hydrate reservoir demonstrate that significant errors can result in reservoir modelling if these fluid transport phenomena are not adequately represented in numerical simulations. Aspects of the model developed here have been applied to history matching and prediction of natural gas recovery from a clastic, sand-dominated reservoir at the Mallik site.
CO2: One-Component Two-Phase System as Model Fluid for High-Pressure Hydrocarbon Systems
Authors: Dupuy P.M.. M. , Fernandino M.. , Svendsen H.F.. F. , Westra R..
Published: January 2011

In the process of performing either scientific experiments or research and development related to the design and optimization of high-pressure liquid-from-gas separator units, both laboratory experiments and tests in prototypes are needed. In order to emulate the low interfacial tensions often experienced in high-pressure hydrocarbon systems, the use of carbon dioxide (CO2) as model fluid is studied. This paper describes how the CO2 system behaves at saturation conditions. It describes this system and compares it with traditional laboratory systems and real fluids (from the field). CO2 at saturation pressure under normal temperatures presents an interesting system with low interfacial tension, below 3 mN/m, while the liquid/gas-density ratio is approximately 3. The availability of the fluid (CO2) in research centers and academia is high. When planning a matrix of experiments as part of a database of reproducible laboratory fluids, the present system is an independent base vector ideal for studying the high-Weber/low-Reynolds-number regime. This paper shows how a dispersed CO2-droplet phase, representative of a hydrocarbon-gas/condensate system, can be achieved in the laboratory and used for studying collision outcomes.

Results show that it is possible to obtain streams of droplets for droplet experiments. The mean diameter in the studied regime with the particular nozzle used was on the order of 100 µm, while the smallest droplets possible to track with the presented technique were approximately 40 µm. Droplet/wall-collision experiments were focused in this work. Both coalescence and bouncing were observed on both dry and wet walls.

The absence of real fluid experiments at laboratory conditions generates a lack of basic knowledge about what is happening in real scrubbers. This system is proposed to be representative for a part of the flow-property region of interest in real gas/liquid scrubbers. This basic knowledge is fundamental when designing separation units at high pressures for gas-processing stages such as subsea gas-separation concepts.
Evaluation of Steam Circulation Strategies for SAGD Startup
Authors: Yuan Jian-Yang , McFarlane Richard
Published: January 2011

The impact of steam quality, circulation rate and pressure difference between the well pair during SAGD initialization using steam circulation was explored through the use of numerical simulations employing a discretized wellbore model. These operating parameters appear to affect uniformity of reservoir heating, occurrence of steam breakthrough and time required to establish communication between the well pair.

The simulation results indicate that, for the given tubing and liner sizes and reservoir properties, relatively lower circulation rates at high-steam quality are more favourable for faster initialization and development of uniform temperature between the horizontal well pair. At lower steam qualities, however, higher circulation rates appear more favourable. The use of high-steam quality in combination with high-circulation rates leads to slower rates of initialization, less uniform heating along the length of the wells and possibility of premature steam breakthrough at the heel. It was also found that having a higher steam quality in the lower well than in the upper well could lead to faster initialization and more uniform heating between the well pair. A small pressure difference, offsetting the natural hydraulic pressure (50 kPa), appears to be more favourable for faster and more uniform initialization.
The quality of drinking water stored in canteens of field soldiers as a potential source of enteric diseases
Authors: Gavrieli Benjamin , Potasman Israel , Armon Robert H.
Published: January 2011

Israel Defense Forces (IDF) guidelines for drinking water require the use of water only from sources that have been inspected and authorized by a medical expert. This study aimed to compare canteen water quality of two military units (infantry and armoured corps), to search for sources of possible microbial contamination and to look for any impact on gastrointestinal symptoms. Statistical analysis revealed that canteens of armoured corp soldiers were significantly more contaminated compared to those of infantry soldiers. Outdoor taps and water in trailers were found to harbour significantly higher numbers of microbial indicators compared to showers/lavatory sources; however, the numbers were much lower compared to canteens. Canteen water retention for more than one day revealed significantly increased numbers of examined microbial parameters, possibly due to secondary contamination or regrowth. Gastrointestinal symptoms were not significantly different between the two units despite the significant canteen water quality difference. An odds ratio evaluation was conducted on 45 exposure-illness combinations based on gastrointestinal symptoms, exposure and soldiers affiliation. Out of these 45 combinations only 14 resulted in odds ratio > 1, where 3 had high values (7.44, 7.46 and 11.2) suggesting a possible connection between diarrhoea and/or vomiting versus coliphages and faecal coliforms.
Evaluating a composite cartridge for small system drinking water treatment
Authors: Muhammad Nur , Sinha Rajib , Krishnan Radha , Patterson Craig L. , Haught Roy C. , Harms Harold H. , Seville Rick
Published: January 2011

A pilot-scale evaluation was conducted at the U.S Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, Ohio, on a multi-layer, cartridge-based system that combines physical filtration with carbon adsorption and ultraviolet (UV) light disinfection to serve as a home-base water treatment security device against accidental or intentional contaminant events. The system was challenged with different levels of turbidity, a number of biological contaminants including Bacillus subtilis, Escherichia coli, MS2bacteriophage and Polystyrene Latex (PSL) beads as a surrogate for Cryptosporidium and a number of chemical contaminants including super-chlorination, methyl tertiary butyl ether (MTBE), water chlorination disinfection byproducts (DBPs) and diazinon. The results demonstrated that the performance of the system varies as a function of the specific contaminant or surrogate. The overall performance indicated the potential of the system to improve the quality and safety of household water and to serve as an additional treatment barrier in circumstances where there is little or no treatment or where the quality of treated water may have deteriorated during distribution. The results also demonstrated that B. subtilis spore can serve as a more conservative surrogate for Cryptosporidium than PSL beads.
Genes encoding tetracycline resistance in a full-scale municipal wastewater treatment plant investigated during one year
Authors: Börjesson Stefan , Mattsson Ann , Lindgren Per-Eric
Published: January 2011

Tetracycline-resistant bacteria and genes encoding tetracycline resistance are common in anthropogenic environments. We studied how wastewater treatment affects the prevalence and concentration of two genes, tetA and tetB, that encode resistance to tetracycline. Using real-time polymerase chain reaction (PCR) we analysed wastewater samples collected monthly for one year at eight key-sites in a full-scale municipal wastewater treatment plant (WWTP). We detected tetA and tetB at each sampling site and the concentration of both genes, expressed per wastewater volume or per total-DNA, decreased over the treatment process. The reduction of tetA and tetB was partly the result of the sedimentation process. The ratio of tetA and tetB, respectively, to total DNA was lower in or after the biological processes. Taken together our data show that tetracycline resistance genes occur throughout the WWTP, and that the concentrations are reduced under conventional operational strategies.
Detection of Giardia and Cryptosporidium cysts/oocysts in watersheds and drinking water sources in Brazil urban areas
Authors: Razzolini Maria Tereza Pepe , da Silva Santos Thaís Filomena , Bastos Veridiana Karmann
Published: January 2011

The protozoan parasites Giardia and Cryptosporidium have been described as important waterborne disease pathogens, and are associated with severe gastrointestinal illnesses. The objective of this paper was to investigate the presence of Giardia cysts and Cryptosporidium oocysts in samples from watershed catchments and treated water sources. A total of 25 water samples were collected and examined according to the US EPA—Method 1623, 2005, consisting of 12 from drinking water and 13 from raw water. Positive samples from raw water for Giardia cysts and Cryptosporidium oocysts were 46.1 and 7.6%, respectively. In finished water, positive samples were 41.7% for Giardia cysts and 25.0% for Cryptosporidium oocysts. Concentrations of Giardia cysts found in raw water samples ranged from “not detected” to 3.4 cysts/L, whereas concentrations of Cryptoporidium oocysts ranged from “not detected” to 0.1 oocysts/L. In finished water, Giardia concentrations ranged from “not detected” to 0.06 cysts/L, and Cryptosporidium, from “not detected” to 0.01 oocysts/L. Concentrations of Giardia cysts and Cryptosporidium oocysts were not high in the samples analyzed. Nevertheless, the results of this study highlight the need to monitor these organisms in both raw and drinking water.
IntegTa: a procedure for integrative management of dammed raw water reservoirs for drinking water production and their lower reaches
Authors: Slavik I. , Uhl W. , Völker J. , Lohr H. , Funke M. , Rolinski S. , Paul L.
Published: January 2011

Dammed water reservoirs for drinking water production with their catchment areas and rivers downstream represent dynamic systems that change constantly and are subject to many influences. An optimized management considering and weighing up the various demands on raw water reservoirs (long-term storage for drinking water supply, flood control, ecological state of the rivers downstream, energy production, nature conservation and recreational uses) against each other is therefore very difficult. Thus, an optimal reservoir management has to take into account scenarios of possibly occurring external influences and to permit predictions of prospective raw water qualities, respectively. Furthermore, the impact of short and long term changes in raw water quality on subordinate processes should be considered. This approach was followed in the work presented here, as there currently is no tool available to predict and evaluate the impacts of raw water reservoir management strategies integratively. The strategy supported by the newly developed decision support procedure takes into account all aspects from water quality, flood control and drinking water treatment to environmental quality downstream the reservoir. Furthermore, possible extreme events or changes of boundary conditions (e.g. climate change) can be considered.
Rainwater harvesting: environmentally beneficial for the UK?
Authors: Way C. M. , Martinson D. B. , Heslop S. E. , Cooke R. S.
Published: January 2011

Rainwater harvesting (RWH) feels right from a long-term sustainability perspective. Short-cutting the hydrological cycle seems to make logical sense from an environmental stance, and the technique is being driven into new buildings in the United Kingdom (UK) through building rating systems which are in turn pushed by government policy. However, little work has been done to assess its environmental credentials from a whole life perspective. Controversially, those studies that have been done have found that RWH systems tend to have greater environmental impacts than mains supply infrastructure. This work seeks to investigate the latest studies, and provide a way forward in the debate.
Planning renewal of water mains while considering deterioration, economies of scale and adjacent infrastructure
Authors: Kleiner Yehuda , Nafi Amir , Rajani Balvant
Published: January 2011

The structural deterioration of water mains and their subsequent failure are affected by many factors, both static (e.g., pipe material, pipe size, age (vintage), soil type) and dynamic (e.g., climate, cathodic protection, pressure zone changes). This paper describes a non-homogeneous Poisson model developed for the analysis and forecast of breakage patterns in individual water mains, while considering both static and dynamic factors. Subsequently, these forecasted breakage patterns are used to schedule the renewal of water mains in an economically efficient manner, while considering the various associated costs, including economies of scale and scheduled works on adjacent infrastructure. In this paper, he principles of the approach are described briefly and its application is demonstrated with the help of a case study.
Graph-based approach for generating virtual water distribution systems in the software VIBe
Authors: Sitzenfrei R. , Möderl M. , Rauch W.
Published: January 2011

Application of virtual case studies (VCS) is a well established technique in environmental engineering to test measures, approaches, models or software. However, preparation of VCS for an infrastructure network is a tedious task. In literature, approaches can be found which generate very simplified VCS, which are only partly comparable with real world case studies. VCS which are more comparable with real world case studies can be generated with the software VIBe (Virtual Infrastructure Benchmarking). With VIBe, a methodology for algorithmic generation of VCS with varying spatially distributed boundary conditions was presented. Therein the investigated infrastructure is constructed accordingly to the state-of-the-art design rules meeting the requirements of the generated virtual urban environment. In this paper the module for the generation of water distribution systems (WDS) is presented. The generated WDS are set in context with data from real world WDS and systematically investigated. A set of 75,000 virtual WDS with varying properties is characterized and stochastically analysed in order to identify system coherences e.g. impact of mesh degree on hydraulic, water quality performance and costs. An example involving the systematic investigation of a simple pipe sizing algorithm with the set of 75,000 WDS is shown.
Repeated Measures Semiparametric Regression Using Targeted Maximum Likelihood Methodology with Application to Transcription Factor Activity Discovery
Authors: Tuglus Catherine , van der Laan Mark J.
Published: January 2011

In longitudinal and repeated measures data analysis, often the goal is to determine the effect of a treatment or aspect on a particular outcome (e.g., disease progression). We consider a semiparametric repeated measures regression model, where the parametric component models effect of the variable of interest and any modification by other covariates. The expectation of this parametric component over the other covariates is a measure of variable importance. Here, we present a targeted maximum likelihood estimator of the finite dimensional regression parameter, which is easily estimated using standard software for generalized estimating equations.

The targeted maximum likelihood method provides double robust and locally efficient estimates of the variable importance parameters and inference based on the influence curve. We demonstrate these properties through simulation under correct and incorrect model specification, and apply our method in practice to estimating the activity of transcription factor (TF) over cell cycle in yeast. We specifically target the importance of SWI4, SWI6, MBP1, MCM1, ACE2, FKH2, NDD1, and SWI5.The semiparametric model allows us to determine the importance of a TF at specific time points by specifying time indicators as potential effect modifiers of the TF. Our results are promising, showing significant importance trends during the expected time periods. This methodology can also be used as a variable importance analysis tool to assess the effect of a large number of variables such as gene expressions or single nucleotide polymorphisms.