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Natural gas hydrates are mostly formed in low-permeability and fractured muddy sedimentary formations. Adding suitable nanoparticles to the drilling fluid system can improve its filtrate resistance and fracture plugging, and effectively weaken the invasion of drilling fluid into the reservoir. However, it is likely that nanoparticles promote hydrate formation and accumulation in wellbores and will induce accidents. Therefore, this study investigated the effect of hydrophilic silica nanoparticles with particle sizes of 30 nm, 60 nm, and 80 nm and concentrations of 0.5–4.0 wt.% on hydrate formation during upward migration of methane gas using a dynamic simulation system for hydrate formation in a wellbore. The experimental results show that under the condition of methane gas migration, hydrophilic silica nanoparticles inhibit hydrate formation. The inhibition effect increased with an increase in the particle size under a constant concentration, whereas it first increased and then decreased with increasing nanoparticle concentration under a constant particle size. The strongest inhibition effect was observed at a hydrophilic silica nanoparticle concentration of 2.0 wt.%. The influence of hydrophilic silica nanoparticles on hydrate formation may be mainly determined by their hydrophilic properties, heat and mass transfer, and gas migration in the wellbore. Our research indicates that hydrophilic silica nanoparticles can be added to hydrate drilling fluid systems if their concentration can be properly controlled.

Additional file 3: Table S2. Difference in clinical manifestations among three groups.

Additional file 4: Table S3. Clinical characteristics of three groups.

Additional file 2: Table S1. Subgroup analyses of B cell subsets according to clinical features.

Early diagnosis is critical to improve outcomes in rheumatoid arthritis (RA), but current diagnostic tools have limited sensitivity. Here we report a large-scale multicenter study involving training and validation cohorts of 3,262 participants. We show that serum levels of soluble scavenger receptor-A (sSR-A) are increased in patients with RA and correlate positively with clinical and immunological features of the disease. This discriminatory capacity of sSR-A is clinically valuable and complements the diagnosis for early stage and seronegative RA. sSR-A also has 15.97% prevalence in undifferentiated arthritis patients. Furthermore, administration of SR-A accelerates the onset of experimental arthritis in mice, whereas inhibition of SR-A ameliorates the disease pathogenesis. Together, these data identify sSR-A as a potential biomarker in diagnosis of RA, and targeting SR-A might be a therapeutic strategy., Scavenger receptor-A (SR-A) is mostly expressed by myeloid cells and has been attributed a variety of biological functions. Here the authors assess SR-A as a biomarker for diagnosis of rheumatoid arthritis (RA) using large-scale training and validation cohorts and show that modulating SR-A levels can alter progression of collagen-induced arthritis in mice.

Objectives : Studies have demonstrated that CK2 is engaged in CD4+ T cell proliferation and activation. We investigated the potential involvement of CK2 in the pathogenesis of rheumatoid arthritis (RA). Methods Peripheral blood and synovial fluid mononuclear cells (PBMC and SFMC) of RA patients, as well as splenocytes of collagen-induced arthritis (CIA) mice were treated with different doses of CK2 inhibitor CX4945 in vitro. Then, the Th1, Th2, Th17, and Treg cell responses were analyzed. In addition, CIA mice were administrated with CX4945 via oral gavage. Accordingly, the arthritis scores, bone destruction, tissue damage, and the CD4+ T cell subsets were assessed. Results The expression of CK2 was upregulated in CD4+ T cells under RA circumstance. In vitro CX4945 treatment significantly inhibited the Th1 and Th17 cell responses, while promoted the Th2 cell responses in RA patient PBMC, SFMC and CIA mouse splenocytes, dampening IFN-γ and IL-17A production. Moreover, administration of CX4945 ameliorated the severity of arthritis in CIA mice, along with decreased Th1 and Th17 cells. However, CX4945 seemed to have minimal effect on RA Treg cells. Conclusion CK2 serves as an important regulator of the Th1 and Th17 cell axes in RA, thus contributing to the disease aggravation.

Gas hydrates that occur in offshore sediments and onshore permafrost represent a vast source of natural gas. However, current gas production trials indicate that sand production, which refers to the migration of sand into boreholes is an obstacle for long-term safe and efficient gas production from gas hydrate reservoirs. Therefore, understanding sand production behaviors during hydrate mining is especially important. In this study, we conducted laboratory-scale tests to investigate the effect of hydrate saturation and overlying stress on the sand production behaviors of hydrate-bearing sediments with a sand screen before, during, and after hydrate dissociation by depressurization. The synthesized methane hydrate saturations and simulated overlying stresses were ~20%, ~30%, ~40%, ~50%, and ~60% and ~11, ~12, ~13, ~14, and ~15 MPa, respectively. The experimental results indicate that sand production before hydrate dissociation is relatively minor and primarily silty. The amount of sand produced increases and silt, fine sand, and medium sand were observed during and after hydrate dissociation. The mass of sand production increases as hydrate saturation increases under constant overlying stress; however, under constant hydrate saturation, it increases then decreases as overlying stress increases. Friction among particles may become the primary control factor once the overlying stress exceeds a critical value. We considered hydrate saturation and overlying stress to establish a sand production prediction model. Our findings help understand sand production behavior using sand screens during gas production from hydrate reservoirs and provide a reference for sand production control design in future hydrate mining.

Understanding of the stability of oil-dominated emulsion, such as the oil-based drilling fluids and crude oils, is of great importance to control the gas hydrate risk management when gas hydrates formation and dissociation occurs in the emulsion. Here, a high-pressure optical capillary cell with micro-Raman spectroscopy is utilized to investigate the effects of hydrate formation and dissociation on the stability of a simulated oil-water emulsion and the micro kinetics near the oil/water interface. Both the hydrate formation and dissociation processes are stimulated in water phase near the oil-water interface. The results show that the oil can enter the water phase from the oil phase with the oil-water interface failure when hydrates rapidly growth very close to the water-oil interface, even resulting in a series of oil droplets in the water phase (oil-droplet trajectory). The interesting phenomenon are mainly caused by the concentration gradient of methane and the Marangoni effect. Subsequently, the hydrate phase dissociates, a new stable water-oil interface presents when the system becomes rebalanced. The methane diffusion behavior induced by the chemical potential gradient in hydrate formation and dissociation processes could affect the stability of the emulsion. In addition, a more profound conceptual hydrate-induced destabilization model for different types of oil-water emulsions is proposed. This study can provide a theoretical and experimental basis for the safe implementation for deep-water oil and gas drilling, hydrate drilling in permafrost and multiphase mixing transportation in pipelines.