Geological and geomechanical characteristics of prospective CO₂ sinks and seals in the Desoto Canyon Salt Basin, east-central Gulf of Mexico

Subsurface geologic storage of CO₂ can play a major role in offsetting greenhouse gas emissions, and offshore storage in the DeSoto Canyon Salt Basin in the east-central Gulf of Mexico may be a viable solution due to large storage capacity (~150) Gt in Cretaceous-Cenozoic sandstone. The Cretaceous reservoirs are overlain by thick sections of tight mudrock, limestone, and chalk, which form regionally extensive seals. Understanding the structural styles and geomechanical properties of the associated reservoir rocks and seals is therefore essential for safe and effective CO₂ storage.The structural framework in the Mississippi-Alabama-Florida shelf of the Gulf of Mexico includes the DeSoto Canyon Salt Basin, the Middle Ground Arch, and the Tampa Embayment. The Central DeSoto Canyon Salt Basin is structurally complex due to the presence of peripheral faults, salt pillows, salt rollers, and salt diapirs. Multiple faults associated with the peripheral faults and salt pillows displace the potential Cretaceous reservoirs and seal intervals. Elongation of borehole breakouts is aligned with the minimum horizontal compressive stress (Shₘᵢₙ), which tends to be oriented northeast-southwest. Vertical reservoir stresses are influenced by rock and fluid density. Lithostatic and hydrostatic stress each have a power-law relationship to depth. The average lithostatic stress (Sv) gradient is ~21.4 kPa/m. Hydrostatic pressure gradient increases with brine density to a maximum of ~12.2 kPa/m. Geometric mean of the Shmin-depth values corresponds to an effective Shmin–effective Sv quotient of ~0.5. Reactivation tendency and seal analysis of the major faults shows that while the slip tendency is small, the dilation tendency and potential for cross-formational flow is relatively high, particularly where reservoir strata in the footwalls are juxtaposed with sealing strata in the hanging walls. Geomechanical analysis of reservoir and seal strata indicates that prospective reservoirs and associated seals are stable if injection pressure does not exceed fracture pressure.Favorable CO₂ injection sites are available throughout the stable shelf areas of the DeSoto Canyon Salt Basin, where faults with high dilation tendency are absent above the Jurassic section. Future research should focus on further geomechanical, pressure, and flow simulation of the potential reservoirs and associated seals

Fracture Architecture of the High Plains Aquifer, Northeastern Texas Panhandle:Implications for Geologic Storage of Carbon Dioxide

Surface and airborne gas monitoring programs are becoming an important part of environmental protection in areas favorable for subsurface storage of carbon dioxide. Understanding structural architecture and its effects on the flux of fluids, specifically CO2 and CH4, in the shallow subsurface and atmosphere is helping design and implement next generation monitoring technologies, including unmanned aerial vehicles (UAVs). An important aspect of this research is using subsurface fracture data to inform the design of flight pathways for UAVs in the Farnsworth Oil Unit of the Anadarko Basin. The High Plains Aquifer of the northeastern Texas Panhandle disconformably overlies Permian and Triassic redbeds and is dominated by weakly to moderately indurated sandstone in the Ogallala Formation. Ogallala strata are overlain by Quaternary strata that include chert and caliche caprock. The target zone for CO2 storage and enhanced oil recovery in the Farnsworth Oil Unit is in upper Morrow sandstone at subsurface depths greater than 2,000 m. Field study reveals that indurated sandstone and chert contain numerous joints that provide crucial insight into aquifer architecture and subsurface flow pathways.Properties of more than 1,700 joints were measured in the field and in high-resolution satellite imagery. The joint networks consist of well-developed systematic joints and cross-joints. In vertical section, the joints are typically curvilinear and strata-bound. Two distinctive joint systems were identified in the study area. Joint spacing follows a log-normal statistical scaling rule. These fractures appear to be the product of regional tectonic stress and may have a significant effect on flow in the High Plains Aquifer system. Based on the results of this research, design of UAV flight paths should be oblique to fractures in a way that maximizes the likelihood of CO2 and CH4 flux from systematic joints and cross joints. Geological risk of leakage from CO2-enhanced oil recovery operations at Farnsworth is low, and multiple potential natural sources of CO2 and CH4 have been identified in near-surface formations. These near-surface sources are predicted to dominate shallow subsurface and atmospheric gas flux.Geolog

Transport anisotropy and metal-insulator transition in striped Dirac fermion systems

Using the determinant quantum Monte Carlo method, we investigate the metal-insulator transitions induced by the stripe of charge density in an interacting two-dimensional Dirac fermion system. The stripe will introduce the transport anisotropy and insulating intermediate phase into the system, accompanied by the change of band structure and a peak of density of states around Fermi energy. In the case of strong correlation, stripe exhibits competition with Coulomb repulsion through closing the energy gap and disrupting the magnetic order, and finally drives the system in Mott insulating phase back to the metallic state. Our results may provide a feasible way to modify transport properties by setting charge stripes in experiments.Comment: 8 pages, 9 figure

Recent Update on the Pharmacological Effects and Mechanisms of Dihydromyricetin

As the most abundant natural flavonoid in rattan tea, dihydromyricetin (DMY) has shown a wide range of pharmacological effects. In addition to the general characteristics of flavonoids, DMY has the effects of cardioprotection, anti-diabetes, hepatoprotection, neuroprotection, anti-tumor, and dermatoprotection. DMY was also applied for the treatment of bacterial infection, osteoporosis, asthma, kidney injury, nephrotoxicity and so on. These effects to some extent enrich the understanding about the role of DMY in disease prevention and therapy. However, to date, we still have no outlined knowledge about the detailed mechanism of DMY, which might be related to anti-oxidation and anti-inflammation. And the detailed mechanisms may be associated with several different molecules involved in cellular apoptosis, oxidative stress, and inflammation, such as AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), protein kinase B (Akt), nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), ATP-binding cassette transporter A1 (ABCA1), peroxisome proliferator-activated receptor-γ (PPARγ) and so on. Here, we summarized the current pharmacological developments of DMY as well as possible mechanisms, aiming to push the understanding about the protective role of DMY as well as its preclinical assessment of novel application

Serotonin Deficiency Exacerbates Acetaminophen-Induced Liver Toxicity In Mice

Acetaminophen (APAP) overdose is a major cause of acute liver failure. Peripheral 5-hydroxytryptamine (serotonin, 5-HT) is a cytoprotective neurotransmitter which is also involved in the hepatic physiological and pathological process. This study seeks to investigate the mechanisms involved in APAP-induced hepatotoxicity, as well as the role of 5-HT in the liver's response to APAP toxicity. We induced APAP hepatotoxicity in mice either sufficient of serotonin (wild-type mice and TPH1-/- plus 5- Hydroxytryptophan (5-HTP)) or lacking peripheral serotonin (Tph1-/- and wild-type mice plus p-chlorophenylalanine (PCPA)).Mice with sufficient 5-HT exposed to acetaminophen have a significantly lower mortality rate and a better outcome compared with mice deficient of 5-HT. This difference is at least partially attributable to a decreased level of inflammation, oxidative stress and endoplasmic reticulum (ER) stress, Glutathione (GSH) depletion, peroxynitrite formation, hepatocyte apoptosis, elevated hepatocyte proliferation, activation of 5-HT2B receptor, less activated c-Jun NH2-terminal kinase (JNK) and hypoxia-inducible factor (HIF)-1α in the mice sufficient of 5-HT versus mice deficient of 5-HT. We thus propose a physiological function of serotonin that serotonin could ameliorate APAP-induced liver injury mainly through inhibiting hepatocyte apoptosis ER stress and promoting liver regeneration

Global Attitude Synchronization of Networked Rigid Bodies Under Directed Topologies

The global attitude synchronization problem is studied for networked rigid bodies under directed topologies. To avoid the asynchronous pitfall where only vector parts converge to some identical value but scalar parts do not, multiplicative quaternion errors are leveraged to develop attitude synchronization protocols for rigid bodies with the absolute measurements. It is shown that global synchronization of networked rigid bodies can be achieved if and only if the directed topology is quasi-strongly connected. Simultaneously, a novel double-energy-function analysis method, equipped with an ordering permutation technique about scalar parts and a coordinate transformation mechanism, is constructed for the quaternion behavior analysis of networked rigid bodies. In particular, global synchronization is achieved with our analysis method regardless of the highly nonlinear and strongly coupling problems resulting from multiplicative quaternion errors, which seriously hinder the traditional analysis of global synchronization for networked rigid bodies. Simulations for networked spacecraft are presented to show the global synchronization performances under different directed topologies.Comment: 26 pages, 6 figure

Cellular pharmacokinetic of methotrexate and its modulation by folylpolyglutamate synthetase and γ-glutamyl hydrolase in tumor cells.

Background and purposeClinical studies showed that prolonged infusion of methotrexate (MTX) leads to more severe adverse reactions than short infusion of MTX at the same dose. We hypothesized that it is the saturation of folate polyglutamate synthetase (FPGS) at high MTX concentration that limits the intracellular synthesis rate of methotrexate polyglutamate (MTX-PG). Due to a similar accumulation rate, a longer infusion duration may increase the concentration of MTX-PG and, result in more serious adverse reactions. In this study, we validated this hypothesis.Experimental approachA549, BEL-7402 and MHCC97H cell lines were treated with MTX at gradient concentrations. Liquid chromatograph-mass spectrometer (UPLC-MS/MS) was used to quantify the intracellular concentration of MTX-PG and the abundance of FPGS and γ-glutamyl hydrolase (GGH). High quality data were used to fit the cell pharmacokinetic model.Key resultsBoth cell growth inhibition rate and intracellular MTX-PG concentration showed a nonlinear relationship with MTX concentration. The parameter Vmax in the model, which represents the synthesis rate of MTX-PG, showed a strong correlation with the abundance of intracellular FPGS.Conclusion and implicationsAccording to the model fitting results, it was confirmed that the abundance of FPGS is a decisive factor limiting the synthesis rate of MTX-PG. The proposed hypothesis was verified in this study. In addition, based on the intracellular metabolism, a reasonable explanation was provided for the correlation between the severity of adverse reactions of MTX and infusion time. This study provides a new strategy for the individualized treatment and prediction of efficacy/side effects of MTX