Natural hydrate-bearing sediments from the Nankai Trough, offshore Japan, were studied using the Pressure Core Characterization Tools (PCCTs) to obtain geomechanical, hydrological, electrical, and ...biological properties under in situ pressure, temperature, and restored effective stress conditions. Measurement results, combined with index-property data and analytical physics-based models, provide unique insight into hydrate-bearing sediments in situ. Tested cores contain some silty-sands, but are predominantly sandy- and clayey-silts. Hydrate saturations Sh range from 0.15 to 0.74, with significant concentrations in the silty-sands. Wave velocity and flexible-wall permeameter measurements on never-depressurized pressure-core sediments suggest hydrates in the coarser-grained zones, the silty-sands where Sh exceeds 0.4, contribute to soil-skeletal stability and are load-bearing. In the sandy- and clayey-silts, where Sh < 0.4, the state of effective stress and stress history are significant factors determining sediment stiffness. Controlled depressurization tests show that hydrate dissociation occurs too quickly to maintain thermodynamic equilibrium, and pressure–temperature conditions track the hydrate stability boundary in pure-water, rather than that in seawater, in spite of both the in situ pore water and the water used to maintain specimen pore pressure prior to dissociation being saline. Hydrate dissociation accompanied with fines migration caused up to 2.4% vertical strain contraction. The first-ever direct shear measurements on never-depressurized pressure-core specimens show hydrate-bearing sediments have higher sediment strength and peak friction angle than post-dissociation sediments, but the residual friction angle remains the same in both cases. Permeability measurements made before and after hydrate dissociation demonstrate that water permeability increases after dissociation, but the gain is limited by the transition from hydrate saturation before dissociation to gas saturation after dissociation. In a proof-of-concept study, sediment microbial communities were successfully extracted and stored under high-pressure, anoxic conditions. Depressurized samples of these extractions were incubated in air, where microbes exhibited temperature-dependent growth rates.
•Hydrate-bearing pressure core analyzed with pressure core characterization tools.•Hydrates concentrated in silty sands are load-bearing.•Produced gas limits permeability increase due to hydrate dissociation.•Peak shear strength depends on hydrate content, residual strength on clay content.•Microbial growth rates depend on temperature.
Geologic reservoirs containing gas hydrate occur beneath permafrost environments and within marine continental slope sediments, representing a potentially vast natural gas source. Numerical ...simulators provide scientists and engineers with tools for understanding how production efficiency depends on the numerous, interdependent (coupled) processes associated with potential production strategies for these gas hydrate reservoirs. Confidence in the modeling and forecasting abilities of these gas hydrate reservoir simulators (GHRSs) grows with successful comparisons against laboratory and field test results, but such results are rare, particularly in natural settings. The hydrate community recognized another approach to building confidence in the GHRS: comparing simulation results between independently developed and executed computer codes on structured problems specifically tailored to the interdependent processes relevant for gas hydrate-bearing systems. The United States Department of Energy, National Energy Technology Laboratory, (DOE/NETL), sponsored the first international gas hydrate code comparison study, IGHCCS1, in the early 2000s. IGHCCS1 focused on coupled thermal and hydrologic processes associated with producing gas hydrates from geologic reservoirs via depressurization and thermal stimulation. Subsequently, GHRSs have advanced to model more complex production technologies and incorporate geomechanical processes into the existing framework of coupled thermal and hydrologic modeling.
This paper contributes to the validation of these recent GHRS developments by providing results from a second GHRS code comparison study, IGHCCS2, also sponsored by DOE/NETL. IGHCCS2 includes participants from an international collection of universities, research institutes, industry, national laboratories, and national geologic surveys. Study participants developed a series of five benchmark problems principally involving gas hydrate processes with geomechanical components. The five problems range from simple geometries with analytical solutions to a representation of the world's first offshore production test of methane hydrates, which was conducted with the depressurization method off the coast of Japan. To identify strengths and limitations in the various GHRSs, study participants submitted solutions for the benchmark problems and discussed differing results via teleconferences. The GHRSs evolved over the course of IGHCCS2 as researchers modified their simulators to reflect new insights, lessons learned, and suggested performance enhancements. The five benchmark problems, final sample solutions, and lessons learned that are presented here document the study outcomes and serve as a reference guide for developing and testing gas hydrate reservoir simulators.
•Code comparisons build confidence in simulators to model interdependent processes.•International hydrate reservoir simulators are compared over five complex problems.•Geomechanical processes significantly impact response of gas hydrate reservoirs.•Simulators yielded comparable results, however many differences are noted.•Equivalent constitutive models are required to achieve agreement across simulators.
The formation of self-organized nanoporous anodic films on Type 304 stainless steel in fluoride-containing ethylene glycol electrolyte is reported. A key factor in the formation of the nanoporous ...anodic films is the water concentration in the electrolyte, which must be 0.3moldm−3 or less for the present conditions of film formation, although nanoporous anodic films have been formed on iron at higher water concentrations. The films contain relatively high concentrations of iron, chromium, nickel, oxygen and fluorine species distributed throughout the film thicknesses. The fluoride species can be removed by post-annealing in air, which improves the chemical stability of the films without damaging the nanoporous morphology of the remaining oxide.
► Self-organized nanoporous anodic films were formed on stainless steel. ► The films grew by the reduction of H2O content in the ethylene glycol electrolytes. ► Post-annealing converted water-soluble oxyfluoride to insoluble oxide.
JLDG is a data-grid for the lattice QCD (LQCD) community in Japan. Several large research groups in Japan have been working on lattice QCD simulations using supercomputers distributed over distant ...sites. The JLDG provides such collaborations with an efficient method of data management and sharing. File servers installed on 9 sites are connected to the NII SINET VPN and are bound into a single file system with the GFarm. The file system looks the same from any sites, so that users can do analyses on a supercomputer on a site, using data generated and stored in the JLDG at a different site. We present a brief description of hardware and software of the JLDG, including a recently developed subsystem for cooperating with the HPCI shared storage, and report performance and statistics of the JLDG. As of April 2015, 15 research groups (61 users) store their daily research data of 4.7PB including replica and 68 million files in total. Number of publications for works which used the JLDG is 98. The large number of publications and recent rapid increase of disk usage convince us that the JLDG has grown up into a useful infrastructure for LQCD community in Japan.
Imaging Atmospheric Cherenkov Telescopes (IACT) are designed to detect γ-ray photons in the very-high energy (VHE) band from 50 GeV to more than 10 TeV. The few degree-scale field of view and the ...good angular resolution < 0.1 deg, favor morphological studies on extended sources and on diffuse emission. The description of the PSF (Point Spread Function) of IACT is a prerequisite to assess, for example, the possibility to reveal diffuse emission around point like sources. We study the PSF on γ-ray photons of IACTs using Crab Nebula data collected with the MAGIC stereoscopic system. Through a careful description of the background and response of the instrument we can build the γ-ray PSF corrected for the angular acceptance. We find a good analytical model describing the γ-ray PSF for IACTs and assess its stability.
Drug-drug interactions (DDIs) via cytochrome P450 (P450) induction are one clinical problem leading to increased risk of adverse effects and the need for dosage adjustments and additional therapeutic ...monitoring. In silico models for predicting P450 induction are useful for avoiding DDI risk. In this study, we have established regression models for CYP3A4 and CYP2B6 induction in human hepatocytes using several physicochemical parameters for a set of azole compounds with different P450 induction as characteristics as model compounds. To obtain a well-correlated regression model, the compounds for CYP3A4 or CYP2B6 induction were independently selected from the tested azole compounds using principal component analysis with fold-induction data. Both of the multiple linear regression models obtained for CYP3A4 and CYP2B6 induction are represented by different sets of physicochemical parameters. The adjusted coefficients of determination for these models were of 0.8 and 0.9, respectively. The fold-induction of the validation compounds, another set of 12 azole-containing compounds, were predicted within twofold limits for both CYP3A4 and CYP2B6. The concordance for the prediction of CYP3A4 induction was 87% with another validation set, 23 marketed drugs. However, the prediction of CYP2B6 induction tended to be overestimated for these marketed drugs. The regression models show that lipophilicity mostly contributes to CYP3A4 induction, whereas not only the lipophilicity but also the molecular polarity is important for CYP2B6 induction. Our regression models, especially that for CYP3A4 induction, might provide useful methods to avoid potent CYP3A4 or CYP2B6 inducers during the lead optimization stage without performing induction assays in human hepatocytes.
Paracoccidioidomycosis is a systemic granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. Its major antigen is a 43 kDa glycoprotein whose peptides embody different ...functions: P10 peptide, a T-cell epitope, induces protective response while P4 and P23 peptides inhibit both, macrophage functions and inflammatory reaction, thus facilitating infection. Here we investigated the modulating mechanisms of the immune response exerted by P4 and P23 involved in the latter inhibitory effect on macrophages. Moreover we analyzed the peptides effects in different models in vivo. While evaluating whether P4 and P23 present systemic anti-inflammatory effects in vivo, we showed that their intraperitonial administration decreased footpad swelling in mice infected with either P. brasiliensis or Mycobacterium bovis. Both, qPCR and ELISA assays suggested that this anti-inflammatory effect depended on alterations in the kinetics of production of innate immunity modulators such as TNF-α, IL6, IL10 and TLR2. IL10 seems to be early produced than TNF-α and IL6, produced later in presence of peptides. Higher doses or intravenously given P4 and P23 resulted in earlier and more prolonged anti-inflammatory effects. Moreover, continuous treatment with P4 and P23 sustained the anti-inflammatory activity throughout.
Eotaxins and their receptor CCR3 have a definitive role for tissue accumulation of eosinophils both under homeostatic and pathologic conditions. However, physiological stimuli that can up‐regulate ...CCR3 in blood‐derived human eosinophils have not been recognized. As a prior gene microarray study revealed up‐regulation of CCR3 in eosinophils stimulated with retinoic acids (RAs), the expression of functional CCR3 was examined. We found that 9‐cis RA and all‐trans RA (ATRA) significantly induced surface CCR3 expression regardless of the presence of IL‐3 or IL‐5. Pharmacological manipulations with receptor‐specific agonists and antagonists indicated that retinoic acid receptor‐α activation is critical for CCR3 up‐regulation. RA‐induced CCR3 was associated with its functional capacity, in terms of the calcium mobilization and chemotactic response to eotaxin‐1 (CCL11). Our study suggests an important role of vitamin A derivatives in the tissue accumulation of eosinophils.
A modified polyol process for the synthesis of cubic‐shaped FeCo particles at 403 K is demonstrated. Control of the particle composition and size was achieved by varying the experimental conditions. ...The Fe content in the FeCo particles can be varied from 90 to 20 mol %, and the size of the cubes can be controlled to obtain particles with sizes between 300 and 35 nm (see figure). The magnetic properties of the particles closely resemble those of bulk FeCo.
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