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The Miller cycle with EIVC is applied to a medium-speed marine diesel engine to achieve high-efficiency combustion and low nitrogen oxide (NOx) emissions. The effects of Miller cycle on the state parameters, combustion characteristics, NO emissions, and the spatial distribution of working fluid were analyzed. A one-dimensional (1D) simulation model was established by using the BOOST software. The FIRE software was used to simulate the combustion process and emission characteristics of the diesel engine at medium and low loads. The results show that in the E3 cycle (four kinds of loads, 100%, 75%, 50%, 25%, according to Marine application propeller law), with the proper EIVC, the in-cylinder pressure, temperature and NO emission will be reduced. At the load of 50%, NO emissions were reduced by 17.8%, At 25% load NO emissions were reduced by 14.9%. During the fuel injection, the decrease of in-cylinder temperature causes a longer ignition delay period. When the EIVC is too early, the heat release rate increases sharply, at the same time, the NO generation also increases. Furthermore, it will lead to misfire at low load.

With the rapid development of the global economy, more vehicle ownership leads to the increasing of environmental pollution in recent years. In response to this matter, exhaust gas recirculation (E...

Glutathione peroxidase is key for the removal of H2O2 and other hydroperoxides and therefore, it has an important role in the maintenance of the reactive oxygen species (ROS) metabolic balance in vivo. The native enzymes of the glutathione peroxidase family (GPx) have many defects, such as instability in vitro and poor availability. GPx mimetics has become a topic of considerable interest in artificial enzyme research. Many forms of GPx mimics have been synthesized, by including selenium and tellurium (double-bridged and single-bridged, 2-substituted and 6-substituted) in a mother molecule but differences the GPx mimics enzymatic activity have rarely been compared. We designed and synthesized eight cyclodextrin derivatives and used two types of enzyme assays to determine their activities. The results show that: (a) tellurium-containing GPx mimics have higher activity than that of selenium-containing GPx mimics; (b) dual-bridged mimics have higher activity than bis-bridged mimics; and (c) 2-position modified cyclodextrin has higher activity than 6-position modified cyclodextrin.

In order to overcome the instability of natural glutathione peroxidase (GPx), scientists endeavor to produce GPx mimics. The popular method first uses biological imprinting (BI) to produce the substrate binding sites and then employs chemical mutation (CM) to obtain the catalytic site. However, BICM has a drawback in that the catalytic site is not clear. Some researchers therefore tried to change the order of the method. These new GPx mimics were prepared by first producing the catalytic site through chemical mutation, and then employing biological imprinting to produce the substrate binding sites (CMBI). It has a clear catalytic site, but its determination of enzyme activity and kinetic analysis are still not elucidated. In this study, we used CMBI to synthesize a GPx mimic using trypsin as the imprinted molecule and GSSG as the template molecule and compared the enzyme activity of the four intermediates (Trypsin-SeO2H (TSeO2H), Trypsin-Se-SG (TSeSG), Imprinted Trypsin-Se-SG (ITSeSG), Cross-linked Imprinted Trypsin-Se-SG (CITSeSG), we analyzed the properties of intermediate products. All values are the means of at least four determinations, ITSeSG was produced from TSeSG through bio-imprinting, the activity of GPx mimics synthesized by CMBI was 5.7 times greater than native GPx, because of bio-imprinting make KmGSH value of the mimics decreased from 4.82 ± 0.27 mM (TSeSG) to 0.52 ± 0.05 mM (ITSeSG). This proves that bio-imprinting is the reason for increased substrate binding capability.

Glutathione peroxidase (GPx) is an antioxidant protein containing selenium. Owing to the limitations of native GPx, considerable efforts have been made to develop GPx mimics. Here, a short 5-mer peptides (5P) was synthesized and characterized using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Enzyme coupled assays were used to evaluate GPx activity. The cell viability and apoptosis of H22 cells were tested, and mice bearing H22 cell-derived tumors were used to determine the effects of 5P on tumor inhibition. In comparison with other enzyme models, 5P provided a suitable substrate with proper catalytic site positions, resulting in enhanced catalytic activity. In our mouse model, 5P showed excellent inhibition of tumor growth and improved immunity. In summary, our findings demonstrated the design and synthesis of the small 5P molecule, which inhibited tumor growth and improved immunity. Notably, 5P could inhibit tumor growth without affecting normal growth. Based on these advantages, the novel mimic may have several clinical applications.

Energy security issues related to China’s economic lifeline and livelihood of our people, also of great significance to maintaining world peace and stability and promoting common development. With China’s rapid economic development of China’s energy demand is also increasing year by year in this article mainly analyzes the current development of China’s energy industry, and development issues, and made recommendations on China’s energy development.