Falutz J.,McGill University |
Potvin D.,Harvard University |
Mamputu J.-C.,Harvard University |
Assaad H.,Harvard University |
And 8 more authors.
Journal of Acquired Immune Deficiency Syndromes | Year: 2010
Background: HIV-infected patients receiving antiretroviral therapy often demonstrate excess visceral fat. A growth hormone-releasing factor, tesamorelin, may selectively reduce visceral fat in this population. We investigated the effects of tesamorelin (GHRH) in HIV-infected patients with central fat accumulation. Methods: A 12-month study of 404 HIV-infected patients with excess abdominal fat in the context of antiretroviral therapy was conducted between January 2007 and October 2008. The study consisted of 2 sequential phases. In the primary efficacy phase (months 0-6), patients were randomly assigned to receive tesamorelin [2 mg subcutaneous (SC) every day] or placebo in a 2:1 ratio. In the extension phase (months 6-12), patients receiving tesamorelin were rerandomized to continue on tesamorelin (2 mg SC every day) or switch to placebo. Patients initially randomized to placebo switched to tesamorelin. Patients and investigators were blinded to treatment assignment throughout the study. The primary endpoint was visceral adipose tissue (VAT). Secondary endpoints included body image, IGF-I, safety measures, including glucose, and other body composition measures. Results: VAT decreased by-10.9% (-21 cm) in the tesamorelin group vs.-0.6% (-1 cm) in the placebo group in the 6-month efficacy phase, P < 0.0001. Trunk fat (P < 0.001), waist circumference (P = 0.02), and waist-hip-ratio (P = 0.001) improved, with no change in limb or abdominal SC fat. Insulin-like growth factor-1 increased (P < 0.001), but no change in glucose parameters was observed. Patient rating of belly appearance distress (P = 0.02) and physician rating of belly profile (P = 0.02) were significantly improved in the tesamorelin vs. placebo-treated groups. The drug was well tolerated. VAT was reduced by approximately 18% (P < 0.001) in patients continuing tesamorelin for 12 months. The initial improvements over 6 months in VAT were rapidly lost in those switching from tesamorelin to placebo. Conclusions: Tesamorelin reduces visceral fat by approximately 18% and improves body image distress in HIV-infected patients with central fat accumulation. These changes are achieved without significant side effects or perturbation of glucose. Copyright © 2010 by Lippincott Williams & Wilkins.
Hovorka S.D.,University of Texas at Austin |
Meckel T.A.,University of Texas at Austin |
Trevino R.H.,University of Texas at Austin |
Lu J.,University of Texas at Austin |
And 19 more authors.
Energy Procedia | Year: 2011
The Southeast Regional Carbon Sequestration Partnership (SECARB) early project in western Mississippi has been testing monitoring tools and approaches to document storage efficiency and storage permanence under conditions of CO2 EOR as well as downdip injection into brine. Denbury Onshore LLC is host for the study and has brought a depleted oil and gas reservoir, Cranfield Field, under CO2 flood. Injection was started in July 2008 and has now achieved injection rates greater than 1.2 million tons/year though 23 wells, with cumulative mass injected as of August, 2010 of 2.2 million metric tons. Injection is into coarse grained fluvial deposits of the Cretaceous lower Tuscaloosa Formation in a gentle anticline at depths of 3300 m. A team of researchers from 10 institutions has collected data from five study areas, each with a different goal and different spatial and temporal scale. The Phase 2 study began at the start of injection and has been using pressure and temperature as a tool for assessing permanence mostly in the oil productive interval. Real-time read-out shows high sensitivity to distant changes in injection rate and confirms the geologic model of reservoir compartmentalization. Above-zone pressure monitoring ∼120 m above the injection interval is used to test the sensitivity of this approach for documentation of integrity of the confining system in an area of numerous well completions as pressure increase is induced in the reservoir by more than 70 bar. Monitoring of the High Volume Injection Test (HiVIT) area includes repeat measurements of aqueous geochemistry in the injection zone. Rock-water-CO 2 interactions in the reservoir as CO2 dissolves are minimized by mineral "armoring" by abundant chlorite cement in high permeability reservoir sandstone. Geochemical monitoring of confined freshwater aquifers at depths of 70-100 m is underway. Groundwater analysis focuses on assessment of the sensitivity of this method to detect leakage above background variability. A repeat seismic survey of the HiVIT is planned for late 2010 to assess saturation change especially in downdip brine-only areas. A study focused on feasibility of monitoring the shallow subsurface to separate leakage from normal complex surface fluxes is underway at an monitoring array installed in October 2009 to assess the interactions of recharge, soil gas, and shallow groundwater aquifers. Recent well re-entry and tracer injection will provide further information to interpret observed elevated deep-sourced methane. The Detailed Area Study (DAS) is collecting dense time-lapse data from closely-spaced three well array of an injector and two observation wells. The observation wells were completed with fiberglass casing to facilitate electrical resistance tomography (ERT) measurements, and a diverse array of instrumentation was both cemented behind casing and suspended on tubing. Injection started at the DAS December 1, 2009. We have measured pulsed neutron and resistivity via wireline, downhole and above-zone pressure, distributed temperature, and fluid chemistry including introduced pulses of perfluorocarbons, noble gases, and SF6 as tracers. Between wells, time-lapse crosswell seismic and electrical resistance tomography (ERT) are used to measure saturation change. The goals are to measure changes as fluids evolve from single phase (brine) to two phase (CO2-brine) in order to document linkages between pressure and sweep efficiency. A time-lapse VSP survey bridges the vertical resolution and areal coverage between cross-well and surface seismic. The repeat surveys for many tools are scheduled for September, 2010. Reservoir characterization based on cores, historic and new wireline log data, production history, hydrologic tests, fluid analysis, and a three-D seismic survey have been used in multiple numerical models to predict reservoir response in order to design effective monitoring strategies and optimize deployment. History matching of observed response to predicted response is used to interpret results and improve confidence in conceptual models and numerical approaches. Probabilistic methods have been used to assess the significant uncertainties resulting from reservoir heterogeneity. © 2011 Published by Elsevier Ltd.
Testa M.A.,Harvard University |
Gill J.,Sanofi S.A. |
Su M.,Multi-phase Technologies, Llc |
Turner R.R.,Multi-phase Technologies, Llc |
And 2 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2012
Context: In patients with diabetes, intraday glucose variability might predict health outcomes independently from glycosylated hemoglobin (HbA 1c). Objective: Our objective was to evaluate patient satisfaction (PS), quality of life (QoL), glycemic control, and variability during insulin intensification to HbA1c below 7.0%. Patients, Design, and Setting: Eighty-two type 1 and 306 insulin-treated type 2 diabetes patients (47% male; age 54 ± 11 yr; HbA1c = 7.8 ± 0.7%) participated in this multicenter, randomized, crossover trial at 52 U.S. centers. Interventions: Interventions included insulin glargine plus premeal glulisine (n = 192) vs. twice-daily premix 75/25 or 70/30 analog insulin (n = 196) for 12 wk and crossed to the alternate arm for 12 wk. Main Outcome Measures: Main outcome measures included PS and QoL questionnaires, 3-d continuous glucose monitoring (CGM), and HbA1c every 4-8 wk. Results: Mean ± SE HbA1c change was -0.39 ± 0.09% for glargine-glulisine and -0.05 ± 0.09% for premix (P < 0.0001). The PS net benefit scale (0-100) improved from 51.1 to 60.5 ± 1.2 for glargine-glulisine and worsened to 45.4 ± 1.2 for premix (P < 0.0001). The PS regimen acceptance scale was comparable (P = 0.33). Overall QoL favored glargine-glulisine (P < 0.001), as did perceived health (P < 0.0001), symptom distress (P < 0.0001), general health perceptions (P < 0.01), and psychosocial (P < 0.02). CGM daily glucose mean, daily glucose SD (glycemic variability), and percent time over 140 mg/dl were lower for glargine-glulisine by 13.1 ± 2.7 mg/dl, 5.9 ± 1.4 mg/dl, and 7.3 ± 1.6%, respectively (all P < 0.0001), with no difference in CGM percent time below 70 mg/dl (P = 0.09). Symptomatic hypoglycemia rates were comparable. HbA1c, mean CGM daily glucose, and glycemic variability were independent predictors of PS net benefit. Conclusions: Patient satisfaction was impacted more positively by improved QoL, reduced glucose variability, and better glycemic control with a basal-bolus regimen than negatively by the burden of additional injections, thereby facilitating insulin intensification and the ability to achieve HbA1c below 7.0%. Copyright © 2012 by The Endocrine Society.
LaBrecque D.J.,Multi-phase Technologies, Llc |
Adkins P.,Multi-phase Technologies, Llc
SEG Technical Program Expanded Abstracts | Year: 2011
The challenges in adapting the electrical resistivity tomography method to large-scale monitoring applications, such as carbon sequestration and enhanced oil recovery, are the need to wire the system back to a single, central site and providing sufficient signal-to-noise ratios in a safe and economical fashion. The first of these challenges is addressed by a modular system each with its own transmitter, receiver, multiplexer and wireless communication capability. The second challenge is addressed by allowing multiple units to transmit simultaneously. It can be shown that using multiple small sources is far more efficient at creating large signals than single high powered transmitters. The multi-source method can also create sensitivity patterns that provide better resolution of deeper targets. © 2011 Society of Exploration Geophysicists.
Breen S.J.,University of California at Irvine |
Carrigan C.R.,Lawrence Livermore National Laboratory |
LaBrecque D.J.,Multi-phase Technologies, Llc |
Detwiler R.L.,University of California at Irvine
International Journal of Greenhouse Gas Control | Year: 2012
Field-scale studies have shown electrical resistivity tomography (ERT) to be an effective tool for imaging resistivity anomalies and monitoring infiltration events in the near subsurface. ERT also shows potential for monitoring supercritical-CO 2 injections, despite deployment challenges in the deep subsurface. We present results from analog bench-scale experiments aimed at evaluating the ability of ERT to quantify the volume and spatial distribution of a resistive fluid injected into a brine-saturated porous medium. Our experiments represent a well-controlled analog for supercritical-CO 2 injection into deep brine aquifers. We injected measured volumes of air into translucent chambers filled with quartz sand, lined with electrodes, and saturated with a low resistivity salt solution. Between injections, a CCD camera captured high-resolution images, and an ERT data acquisition system scanned the chamber. Processing of the CCD images using quantitative visualization techniques resulted in high-resolution measurements of the spatial distribution and saturation of the injected gas. Direct comparison to inverted resistivity fields then provided a quantitative measure of the ability of ERT to estimate the total volume of injected gas and its spatial distribution within the chamber. We present results from two experiments designed to represent different injection scenarios: (A) low injection rate and strong capillary barrier and (B) high injection rate and weaker capillary barrier. Results show that ERT provided good estimates of the shape, size and location of the primary plume, but overestimated brine saturation within the plume and did not detect thin pathways of gas from the injection port or within the overlying capillary barrier. ERT measurements also indicated a change in saturation within the primary plume that corresponded with observed leakage through the capillary barrier in (B), demonstrating the potential utility of ERT as a leakage-monitoring tool. Repeated ERT scans during our experiments led to degradation in data quality that corresponded with an increase in measured contact resistance. Decreased data quality over time is clearly a concern for ERT implementation as a long-term monitoring strategy and deserves further study to quantify the responsible mechanisms. © 2012 Elsevier Ltd.
Carrigan C.R.,Lawrence Livermore National Laboratory |
Yang X.,Lawrence Livermore National Laboratory |
LaBrecque D.J.,Multi-phase Technologies, Llc |
Larsen D.,Promore Industries Core Laboratory |
And 7 more authors.
International Journal of Greenhouse Gas Control | Year: 2013
Deep geologic sequestration of carbon dioxide (CO2) is being evaluated internationally to mitigate the impact of greenhouse gases produced during oil- and coal-based energy generation and manufacturing. Natural gas producing fields are particularly attractive sites for sequestration activities owing to the assumption that the same geologic barrier or cap rock permitting the subsurface regime to act as a long term natural gas reservoir will also serve to permanently contain the injected supercritical CO2. Electrical resistance tomography (ERT) can potentially track the movement and concentration of the injectate as well as the degree of geologic containment using time lapse electrical resistivity changes resulting from injecting the super-critical fluid into the reservoir formation. An experimental cross-well ERT system operated successfully for more than one year obtaining time lapse electrical resistivity images during the injection of approximately one-million tons of CO2 at a depth exceeding 3000m in an oil and gas field in Cranfield, MS, representing the deepest application of the method to date. When converted to CO2 saturation, the resultant images provide information about the movement of the injected CO2 within a complex geologic formation and the development of the saturation distribution with time. ERT demonstrated significant potential for near real-time assessment of the degree of geologic containment and for updating risk analyses of the sequestration process. Furthermore, electrical resistivity imaging of the developing CO2 distribution may provide crucial input about the developing reservoir pressure field that is required for active reservoir management to prevent the occurrence of cap-rock-damaging seismic activity. © 2013 Elsevier Ltd.
Multi-phase Technologies, Llc | Date: 2013-01-15
Hardware and software for use in electrical resistivity imaging; leasing of hardware and software for use in electrical resistivity imaging, consulting in the field of electrical resistivity imaging. Leasing of computer hardware and software for use in electrical resistivity imaging; consulting in the field of electrical resistivity imaging.
Multi-phase Technologies, Llc | Date: 2015-10-05
A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 381.93K | Year: 2010
An effort is underway by the U.S. DOE to develop cost-effective and environmentally sound technologies in order to help to stabilize atmospheric concentrations of CO2 and to reduce greenhouse gas emissions. There is a significant need for economical methods to characterize potential sequestration reservoirs as well as determine the extent, location and nature of leaks from reservoirs both to assure that CO2 is effectively sequestered for long periods of time, and to reduce the likelihood of local environmental impacts. Electrical Resistivity Tomography (ERT) is a geophysical tool that has been used successfully to image the electrical resistivity of the subsurface, and is especially sensitive to pore fluid content. ERT is capable of monitoring movement of sequestered CO2 by measuring the change in the electrical resistivity of the subsurface, both in the saturated and vadose zones. Our ERT system under development consists of many, inexpensive, self-contained units that communicate with each other through a distributed wireless network. The capital expense of such a system would be relatively small. The operating expenses, once the system is automated, would also be small. In the Phase I project, the prototype system design was completed, a preliminary version of a new survey design strategy was implemented and a strategy for employing multiple, simultaneous current sources was developed. The new strategy will increase signal to noise levels and enhance target resolution. In Phase II Year 1 we will complete fabrication of the prototype system and operation software and adapt imaging routines for the multi-source strategy. We will complete all design upgrades and perform unit as well as full scale field tests in Year 2. Commercial Applications and Other Benefits There is a significant need for cost-effective methods to monitor CO2 sequestrationreservoirs in order to reduce the likelihood of local environmental impacts. This project will develop a cost-effective method of monitoring sequestration reservoirs for potential leakage pathways and for reservoir integrity using a geophysical method, Electrical Resistivity Tomography (ERT)
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.39K | Year: 2013
The U.S. DOE Office of Environmental Management (EM) was created in 1989 to manage the cleanup of large areas of environmentally contaminated sites. Since the closure of many of these sites, U.S. taxpayers have spent about $220 billion at 74 cleanup sites. However, these sites were the smallest and most manageable sites to clean. There are still over 40 sites that are deemed as enormous challenges. Among the most difficult challenges are those sites that involve fractured rock aquifers. Such sites include the Nevada Test Site, Hanford Reservation, the proposed nuclear repository at Yucca Flats, as well as other privately managed sites. These sites contain boreholes for monitoring possible contamination, but the boreholes can impact the hydrologic systems creating potential leakage pathways. Making the best use of the boreholes is critical to both cleanup and long-term stewardship of these sites. We will develop a method that combines electrical resistivity tomography (ERT) with borehole magnetometric resistivity (BMR) in order to provide detailed images around one or more boreholes at much greater resolution than surface geophysical methods and with greater depth into the formation than borehole logging techniques. Unlike cross-hole geophysical methods that require multiple closely-spaced boreholes, our method could be applied from either a single borehole or widely spaced holes. The system will be designed for rapid, inexpensive deployment. At present, there is no integrated, commercial quality system for acquisition, processing, interpretation and display of combined ERT and BMR data. One aspect of this project would be to develop an ERT and BMR string with an integrated clamp system to allow collection of ERT data in boreholes and to stabilize the magnetic sensor within the borehole. Another aspect is to develop a software interpretation package designed specifically for imaging fractured rock environments and contaminant transport flow. An inexpensive, cost-effective method of imaging that can be performed in single wells or widely spaced wells would impact the way boreholes are located, sites are characterized, and long-term monitoring. Additional savings would occur by substantially reducing the number of boreholes, improving the information from boreholes and optimizing the location of boreholes themselves. This is critical in fractured rock environments where hydrogeology is complex, the drilling costs are high and the chance of creating leakage pathways is high.