7-Ketocholesterol Induces Cell Apoptosis by Activation of Nuclear Factor kappa B in Mouse Macrophages

We investigated the molecular mechanisms responsible for the induction of apoptosis in mouse monocytic macrophage cell line J774A.1 stimulated by 7-ketocholesterol (7-KC). Cell apoptosis was detected by Annexin V-propidium iodide (PI) staining. The DNA-binding activity of nuclear factor kappa B (NF-kappaB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that 7-KC-stimulation in J774A.1 cells activated NF-kappaB, which is involved in cell apoptosis, in a time- and dose-dependent manners. 7-KC was also found to increase the binding activity of NF-kappaB to specific DNA binding sites, a possible mechanism for the induction of the cell apoptosis. Moreover, these effects were partially inhibited by pyrrolidine dithiocarbamate (PDTC), an NF-kappaB inhibitor. Taken together, 7-KC may be an important factor in atherosclerosis due to the ability of 7-KC to induce cell apoptosis, which is at least partially mediated through the activation of NF-kappaB.</p

The fast light of CsI(Na) crystals

The responds of different common alkali halide crystals to alpha-rays and gamma-rays are tested in our research. It is found that only CsI(Na) crystals have significantly different waveforms between alpha and gamma scintillations, while others have not this phenomena. It is suggested that the fast light of CsI(Na) crystals arises from the recombination of free electrons with self-trapped holes of the host crystal CsI. Self-absorption limits the emission of fast light of CsI(Tl) and NaI(Tl) crystals.Comment: 5 pages, 11 figures Submit to Chinese Physics

Effect of pre-solid solution treatment of secondary carbides on the microstructure and mechanical properties of Ti(C,N)-based cermets

Promoting favorable wettability between the ceramic hard phase and the metal binder phase is crucial for attaining desirable properties in Ti(C,N)-based cermets, wherein the presence of a typical core-rim structure plays a critical role. In this work, two pre-solution powders were synthesized using carbon thermal reduction technology to replace single or less-component of carbides while keeping the nominal composition unchanged. Employing thermal stability analyses of pre-solid solution powders, the effect of pre-solid solution treatment on the microstructure and mechanical properties of cermets were investigated. Results showed that (Ti,W,Ta,Mo)C exhibits higher thermal stability and accelerates the metallurgical reactions compared with (Ti,W,Ta)C. Thicker rim phase and less rimless-black-core grains formed with the increase of component in the solid solution powders, because of the significantly retarded dissolution of high-thermal-stability solid solution carbides in the binder phase. Under identical conditions of composition and sintering process, the attainment of optimal comprehensive mechanical performance in Ti(C,N)-based cermets was achieved through the strategic incorporation of (Ti,W,Ta)C dopants. It indicates that a suitable pre-solid solution treatment for secondary carbides can further improve the performance

Multiple Synergistic Drilling Fluid System Application in Aihu Oilfield

The unstable layer of Aihu oilfield is characterized by strong hydration dispersion and weak expansion. The theory of multiple synergistic wall stabilization was applied to improve synergistic efficiency of the drilling fluid. The recipe of multiple synergistic drilling fluid is worked out. The multiple synergistic drilling fluid was evaluated by analysing the rheology, filtration, wall building, inhibition for the borehole & the weak layers. The inhibition and rheology of the tested drilling fluid system is as good as anti-temperature performance. The ternary-inhibitive drilling fluid system is superior to the binary-inhibitive drilling fluid system. The ternary-inhibitive contained in the multiple synergistic drilling fluid system enhances the ability of water dispersion inhibition. The application of Aihu oilfield shows that the multiple synergistic drilling fluid has satisfied the requirements of low filtration and slight wall expansion

Factory-like Optimum Drilling Design of Cluster Well in Jimsar Well Block

The deep heavy oil reservoir of Jimsar well block, which located in Xinjiang oilfield, was developed by cluster well in 2016. In view of the ground environment, long open hole section and poor wellbore stability, the scheme which based on the research of factory-like wellsite platform deployment, well trajectory design and reservoir protection, was designed and carried out in the block. Firstly, the platform was divided into different control regions according to the anti-collision requirement. Secondly, truck-mounted drilling rig and civil power were applied to the factory-like drilling. Thirdly, well track was designed to be three parts: straight, increase and steady. The design can improve the proportion of composite drilling footage. Fourthly, the method of plane scanning and normal surface scanning was adopted to ensure the safety of downhole trajectory. Finally, the natural polymer drilling fluid system and drilling fluid reuse system were used to protect environment and reduce drilling cost. The results show that the maximum reducing time of single drill rig is 32.5 day, and the penetration rate of whole platform is increasing continuously

Factory-like Optimum Drilling Design of Cluster Well in Jimsar Well Block

The deep heavy oil reservoir of Jimsar well block, which located in Xinjiang oilfield, was developed by cluster well in 2016. In view of the ground environment, long open hole section and poor wellbore stability, the scheme which based on the research of factory-like wellsite platform deployment, well trajectory design and reservoir protection, was designed and carried out in the block. Firstly, the platform was divided into different control regions according to the anti-collision requirement. Secondly, truck-mounted drilling rig and civil power were applied to the factory-like drilling. Thirdly, well track was designed to be three parts: straight, increase and steady. The design can improve the proportion of composite drilling footage. Fourthly, the method of plane scanning and normal surface scanning was adopted to ensure the safety of downhole trajectory. Finally, the natural polymer drilling fluid system and drilling fluid reuse system were used to protect environment and reduce drilling cost. The results show that the maximum reducing time of single drill rig is 32.5 day, and the penetration rate of whole platform is increasing continuously

Microstructure Observation and Nanoindentation Size Effect Characterization for Micron-/Nano-Grain TBCs

Microstructure observation and mechanical properties characterization for micron-/nano-grain thermal barrier coatings were investigated in this article. Scanning electron microscope images demonstrated that both micron-grain coating and nano-grain coating had micrometer-sized columnar grain structures; while the nano-grain coating had the initial nanostructures of the agglomerated powders reserved by the unmelted particles. The mechanical properties (hardness and modulus) of micron-/nano-grain coatings were characterized by using nanoindentation tests. The measurements indicated that the nano-grain coating possessed larger hardness and modulus than the micron-grain coating; which was related to the microstructure of coatings. Nanoindentation tests showed that the measured hardness increased strongly with the indent depth decreasing; which was frequently referred to as the size effect. The nanoindentation size effect of hardness for micron-/nano-grain coatings was effectively described by using the trans-scale mechanics theory. The modeling predictions were consistent with experimental measurements; keeping a reasonable selection of the material parameters

Optimization of drilling parameters based on Copula function method for the Chepai area

In areas with complex stratigraphic lithology, the relationship between the penetration rate and drilling parameters should be fully considered to optimize the drilling process and improve drilling efficiency. The most frequently utilized methods for performing parameter optimization through correlation analysis are the correlation coefficient, principal component analysis, and grey correlation. The correlation coefficient method solely evaluates the extent of linear correlation between two variables, it cannot be applied to the non-linear connection between penetration rate and drilling parameters. The application of principal component analysis may produce inaccurate experimental findings due to the intricate and poorly co-varying nature of drilling parameters. The grey correlation method can lead to the substantial bias in the results because of the vast quantity of data analysed. Based on the vast quantity of data, using the copula function, the big data analysis method analyses the nonlinear relationship between penetration rate and drilling parameters. It constructs a united distribution function expression to determine the optimal parameter selection criteria. The in-situ drilling data from dozens of wells in the Chepaizi area are collected and optimized six types of parameters. The optimal parameter combination is determined. Following field investigation, there was a noteworthy increase of 34.83% in the average penetration rate

Precipitation of γ′ in the γ binder phase of WC-Al-Co-Ni cemented carbide: A phase-field study

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