Functional characterization of short-type peptidoglycan recognition proteins (PGRPs) from silkworm Bombyx mori in innate immunity.

Peptidoglycan recognition proteins (PGRPs) are members of an important class of pattern recognition receptors in insects that can specifically recognize peptidoglycan (PGN) in bacterial cell walls and participate in immune regulation and bacterial clearance. Although the role of PGRPs in regulating the innate immune response in Drosophila melanogaster has been studied, little is known regarding PGRPs in Lepidoptera species. In this study, five short (S)-type Bombyx mori PGRPs (BmPGRPs) were cloned, expressed, and evaluated for their function in innate immunity. B. mori larvae that were injected with the gram-positive bacterium Bacillus megaterium or the gram-negative bacterium Escherichia coli exhibited a rapid and significant upregulation in S-type BmPGRP expression. The results showed that the five evaluated BmPGRPs have significant agglutination activity toward E. coli and B. megaterium and more notable amidase activity toward meso-diaminopimelic acid peptidoglycan (DAP-PGN). Furthermore, only in the presence of BmPGRP-S5 did B. mori larval hemocytes exhibit significant phagocytosis against E. coli and B. megaterium.

[Experimental research of purification NO-containing gas by aqueous oxidation with UV/H2O2].

The influence of some experimental factors on removal efficiency of nitric oxide (NO) under the condition of liquid-phase oxidation with UV/H2O2, such as H2O2 concentration, solution temperature, initial pH, NO concentration, illumination condition, O2 content and gas flow rate, were investigated by employing orthogonal experiments and single factor experiments. The results showed that NO could be efficiently removed by the aqueous oxidation technology with UV/H2O2 system, and the highest NO removal rate was about 80%. Moreover, H2O2 concentration, temperature and initial pH had varying degree effects on purifying NO-containing gas, whereas NO removal rate were more affected by H2O2 concentration and temperature. The single factor experimental results showed that high NO removal rate could be obtained when H2O2 concentration was 0.2 mol/L and the initial pH was 6-7. H2O2 concentration and initial pH should be maintained at an appropriate level or the production of *OH could be restricted, which would result in lower NO removal rate. The optimum operation temperature was 40 degrees C, which is lower than common operating temperature (50 degrees) for the wet scrubber. Enlarging the illumination strength and O2 content could improve the NO removal rate. Furthermore, the NO removal rate was also controlled by the area and coefficient of gas-liquid mass transfer.

Effects of cake collapse caused by deposition of fractal aggregates on pressure drop during ceramic filtration.

A cake collapse model was developed by taking the combined effects of fractal dimension, relaxation ratio, coordination number, and aggregate diameter into consideration. The cake porosity including intraaggregate and interaggregate porosities was modeled successively by three typical coordination numbers (n = 6, 8, and 12). Accordingly, an inversion method made it possible to deduce the coordination number using the measured cake porosities, and the reverse-calculated value with minimum error and the corresponding relaxation ratios were applied as the parameters for the model. As a result, the profiles of intraaggregate and interaggregate porosities and cake porosity were respectively predicted in contrast to the integrated variation of the relaxation ratio and the fractal dimension. Furthermore, a comparison between the model predictions of the cake pressure drop gradients with and without aggregate compression was conducted to validate the presence of cake collapse. The results show that the predictions based on the proposed collapse model are in agreement with the experiments, and the coordination number is one of the key factors that must be incorporated into the cake collapse models.

[Research on SCR denitrification of MnOx/Al2O3 modified by CeO2 and its mechanism at low temperature].

The Al2O3,which has large specific surface area and is used as carrier,was prepared by sol-gel method in this study. Series catalysts of MnOx, CeO2 plus MnOx supported on Al2O3 by isometric impregnation method. The SCR denitrification experimental conditions were as follows: NH3 as reductive agent, certain gas velocity and suitable ratio of gas mixed was setup. Furthermore, the experiments of BET, XRD and SEM were also carried out respectively in order to obtain physicochemical properties of the prepared catalysts. The experimental results showed that the loading of active component and calcination temperature made a big difference to the catalysts' performance. With appropriate addition of CeO2, MnOx/Al2O3 exhibits better activity and stability. For MnOx/Al2O3, the catalytic activity on NO was greatly influenced by its loaded content, and 7% MnOx/Al2O3 showed superior catalytic activity among the MnOx/Al2O3. The addition of CeO2 could greatly improve the dispersibility of MnOx on the carrier and increase its catalytic activity. The 4% CeO2 addition was the optimum loaded mass precent. Forthermore, 550 degrees C is the best calcination temperature, as MnOx formed different crystalline phases with temperature, at the same time, the addition of CeO2 could affect MnOx crystalline phase. The catalytic mechanism of SCR on NO was also discussed.

[Study on the mathematic model about surfactants screening used for smoke wet purification].

Surfactants increase wetting, solubilization of carbon black and reduce interfacial tension between surfactants and carbon black are very important for the wet removal of furnace smoke. Calculated hydrophile-lipophile balance value (HLB), critical micelle concentration (CMC) and Gibbs-free-energy (deltaG0(mf)) of mixed surfactants solution generated on the basis of selected mathematical models. The CMC of AEO-9, SDBS solution at different ratios and smoke removal efficiency at the CMC were gained by experiments. The relation among HLB, CMC and deltaG0(mf) in mixed surfactants were analyzed. At last, new mathematic models were established about them. The results showed that the calculated data had good agreement with the experimental data. HLB was linearly correlate with ln [CMC]. There was a quadratic relationship between deltaG0(mf) and smoke removal efficiency. The reducing CMC could effectively increase HLB value and solubility, while the deltaG0(mf) and surface tension were both decreased, which could form micelles more spontaneously and enhance smoke removal significantly.

[Reaction of NO with metal oxides and urea supported on activated carbons at low temperature].

The catalysts were prepared by activated carbon fiber (ACF) loaded different contents of NiO and NiO-CeO2, Urea was loaded on the prepared catalysts as reductant. The experiments of selective catalytic reductions (SCR) of NO were carried out from 30 to 120 degrees C. The experiments of SEM, BET and XRD of the samples were also carried out selectively to study the catalysts properties, respectively. The experimental results showed that the loaded mass fraction of NiO could greatly affect the catalytic activity of the catalysts. 10% NiO catalyst activity and activity stability were both higher than that of the others, and it could yield about 50% removal efficiency of NO at 90 degrees C. With the loaded mass increasing, the catalytic activity was obviously decreased. And furthermore, the catalyst of 5% NiO-5% CeO2/ACF had the best catalytic activities on SCR NO and stability among the prepared NiO-CeO2/ACF catalysts, and its NO removal efficiency was over 55% at 110 degrees C. When the loaded mass increased, the similar phenomenon was observed, which was due to the decreasing of specific surface area of the catalysts. The metal oxides, loaded on ACF, were the catalytic centers in this study. Moreover, 5% CeO2-5% NiO/ACF had the highest catalytic activity than 10% CeO2/ACF and 10% NiO/ ACF. Therefore, there should be synergistic effect between CeO2 and NiO. Finally, the catalytic mechanism of SCR on NO at low temperature was discussed.

[Catalytic purification of NO over active carbon fiber-loaded La2O3 catalysts].

The active carbon fiber (ACF) loaded different contents of La2O3 catalysts were prepared, and their catalytic activities and durability for the purification of NO were investigated, and for comparison, those of ACF and HNO3/ACF for the title reaction were also investigated. The orthogonal experiment results showed that the best volume fraction of oxygen in the mixed gas was 5%, and the best air speed of mixed gas was 5000 m3 (m3 x h)(-1). The catalytic experiment results showed that the activity of HNO3/ACF was better than that of ACF when the temperature was below 414.08 degrees C, but the activity durability of HNO3/ACF was inferior than that of ACF. The activity and the activity durability of ACF could be markedly increased when it was loaded La2O3 catalyst, the activity center of the catalyst was La2O3, and the La2O3 catalyst best load amount was 20%, the activity of 20% La2O3/ACF would above 95% when the temperature was higher than 350 degrees C, and its activity durability was about 8 h, which was superior than most of the catalysts that had been reported. The results of FT-IR and TG experiments also showed that the NO purification principle of ACF and HNO3/ACF was different from that of La2O3/ACF, when NO was purified by La2O3/ACF, the competition reactions took place between CO and NO.