岩黄连总碱对巨噬细胞M1型分化的抑制作用

目的:研究岩黄连总碱(CSBTA)对巨噬细胞M1型分化的影响。方法:THP-1细胞经佛波脂(PMA)刺激48 h诱导分化为巨噬细胞(Mφ)。倒置显微镜观察细胞形态变化,流式细胞术检测巨噬细胞表面分子CD11b、CD14;加入脂多糖(LPS,1μg/mL)、γ干扰素(IFN-γ,20 ng/mL)刺激48 h诱导Mφ巨噬细胞分化为M1型巨噬细胞。不同浓度(0.0025 g/L-0.02 g/L)CSBTA干预M1型巨噬细胞24 h。采用实时荧光定量PCR(RT-qPCR)法检测肿瘤坏死因子(TNF)-α和白细胞介素(IL)-6 mRNA相对表达量,Western blotting法检测M1型巨噬细胞CD86蛋白表达量,酶联免疫吸附试验(ELISA)法检测细胞培养上清液中IL-1β的含量。结果:0.02 g/L的CSBTA对M1型巨噬细胞活力产生明显的毒性作用(P<0.05)。在0.0025 g/L、0.005 g/L CSBTA的干预下,M1型巨噬细胞IL-6和TNF-αmRNA相对表达量、CD86蛋白表达量及IL-1β含量均显著降低(均P<0.05)。结论:CSBTA可以有效抑制THP-1源性巨噬细胞M1型的分化,并改善炎症环境。

Dissociation characteristics of methane hydrate using depressurization combined with thermal stimulation

Methane hydrate is considered as a potential energy source in the future due to its abundant reserves and high energy density.To investigate the influence of initial hydrate saturation,production pressure,and the temperature of thermal stimulation on gas production rate and cumulative gas production percentage,we conducted the methane hydrate dissociation experiments using depressurization,thermal stimulation and a combination of two methods in this study.It is found that when the gas production pressures are the same,the higher the hydrate initial saturation,the greater change in hydrate reservoir temperature.Therefore,it is easier to appear the phenomenon of icing and hydrate reformation when the hydrate saturation is higher.For example,the reservoir temperature dropped to below zero in depressurization process when the hydrate saturation was about 37%.However,the same phenomenon didn’t appear as the saturation was about 12%.This may be due to more free gas in the reservoir with hydrate saturated of 37%.We also find that the temperature variation of reservoir can be reduced effectively by combination of depressurization and thermal stimulation method.And the average gas production rate is highest with combined method in the experiments.When the pressure of gas production is 2 MPa,compared with depressurization,the average of gas production can increase 54%when the combined method is used.The efficiency of gas production is very low when thermal stimulation was used alone.When the temperature of thermal stimulation is 11℃,the average rate of gas production in the experiment of thermal stimulation is less than 1/3 of that in the experiment of the combined method.

Fe3C-N-doped carbon modified separator for high performance lithium-sulfur batteries

A new Fe3C-N-doped reduced graphene oxide(Fe3C-N-rGO)prepared by a facile method is used as a separator for high performance lithium-sulfur(Li-S)batteries.The Fe3C-N-rGO is coated on the surface of commercial polypropylene separator(Celgard 2400)close to the sulfur cathode.The special nanotubes are in-situ catalyzed by Fe3C nanoparticles.They could entrap lithium polysulfides(Li PSs)to restrain the shuttle effect and reduce the loss of active material.The battery with the modified separator and sulfur cathode shows an excellent cycle performance.It has a high rate performance,580.5 mAh/g at the high current rate of 4 C relative to 1075 mAh/g at 0.1 C.It also has an initial discharge capacity of 774.8 m Ah/g measured at 0.5 C and remains 721.8 mAh/g after 100 cycles with a high capacity retention of 93.2%.The outstanding performances are notable in recently reports with modified separator.

Adsorption isotherms and kinetic characteristics of methane on block anthracite over a wide pressure range

It is important to quantitatively understand the methane adsorption and transport mechanism in coal for an evaluation of the reserves and for its production forecast. In this work, a block coal sample was chosen to perform the CH_4 adsorption experiments using the gravimetric method at temperatures of 293.60 K, 311.26 K, 332.98 K and 352.55 K and pressures up to 19 MPa. The excess adsorption capacity of CH_4 in dry block anthracite increased, followed by a sequence decrease with the increasing pressure. High temperature restrained the growth of the excess adsorption due to that the adsorption is an intrinsically physical and exothermic process. The excess adsorption peak decreased slowly with the increase of temperature and intersected at a pressure of more than 18 MPa; meanwhile, the pressure at the excess adsorption peak increased. The existing correlations were exanfined in terms of density rather than pressure. The DR＋k correlation, with an average relative deviation of 4-0.51%, fitted our data better than the others, with an average relative deviation of up to 2.29%. The transportation characteristics of CH_4 adsorption was also investigated in this study, including the adsorption rate and diffusion in block coal. The kinetic data could be described by a modified unipore model. The adsorption rates were found to exhibit dependence on pressure and temperature at low pressures, while the calculated diffusivities exhibited little temperature dependence. In addition, the kinetic characteristics were compared between CH_4 and CO_2 adsorption on the block coal. The excess adsorption ratios of CO_2 to CH_4 obtained from the DR＋k model decreased with the increasing pressure.

A review of the gas hydrate phase transition with a microfluidic approach

Over the years,natural gas hydrates(NGHs)have attracted significant attention as an emerging energy resource.Microfluidics is a novel technology used to observe the behaviour of NGHs in microchannels directly and has been applied to hydrates.Gas hydrate distributions and phase transitions are key parameters for exploitation and application.In this paper,advances in related research with microfluidics-based technology are reviewed,including the hydrate phase transition process and its mechanism of influence.Hydrate formation and decomposition directly influence the efficiency and sustainability of exploitation.In addition,studies of the hydrate phase transition provide basic data for future commercial exploitation.Moreover,extended applications,further developments and potential improvements in microfluidic techniques are also discussed.We believe that with an improved understanding of the hydrate phase transition mechanism,commercial exploitation of hydrates can be expected soon.

High-resolution characterization of hexagonal boron nitride coatings exposed to aqueous and air oxidative environments

Hexagonal boron nitride （h-BN） is believed to offer better passivation to metallic surfaces than graphene owing to its insulating nature, which facilitates blocking the flow of electrons, thereby preventing the occurrence of galvanic reactions. Nevertheless, this may not be the case when an h-BN-protected material is exposed to aqueous environments. In this work, we analyzed the stability of mono and multilayer h-BN stacks exposed to H202 and atmospheric conditions. Our experiments revealed that monolayer h-BN is as inefficient as graphene as a protective coating when exposed to H202. Multilayer h-BN offered a good degree of protection. Monolayer h-BN was found to be ineffective in an air atmosphere as well. Even a 10-15 layers-thick h-BN stack could not completely protect the surface of the metal under consideration. By combining Auger electron spectroscopy and secondary ion mass spectrometry techniques, we observed that oxygen could diffuse through the grain boundaries of the h-BN stack to reach the metallic substrate. Fortunately, because of the diffusive nature of the process, the oxidized area did not increase with time once a saturated state was reached. This makes multflayer （not monolayer） h-BN a suitable long-term oxidation barrier. Oxygen infiltration could not be observed by X-ray photoelectron spectroscopy. This technique cannot assess the chemical composition of the deeper layers of a material. Hence, the previous reports, which relied on XPS to analyze the passivating properties of h-BN and graphene, may have ignored some important subsurface phenomena. The results obtained in this study provide new insights into the passivating properties of mono and multilayer h-BN in aqueous media and the degradation kinetics of h-BN-coated metals exposed to an air environment.