In situ catalytic conversion of biomass fast pyrolysis vapors on HZSM–5

In situ catalytic conversion of biomass fast pyrolysis vapors was carried out on HZSM-5 with varying Si/Al ratios(ranging from 20 to 300) at 450 °C. The effects of Si/Al ratios of HZSM-5 zeolites on the distribution of biomass fast pyrolysis products and carbon deposits on catalysts were investigated. It was quite remarkable that after in situ catalytic conversion the amount of light phenols and hydrocarbons increased significantly while that of heavy phenols decreased a lot. Besides, the yield of cyclopentenones with relatively low oxygen content generally increased. It also indicated that as the Si/Al ratios of HZSM-5 increased, the amount of hydrocarbons and light phenols was found to drop greatly. The amount of carbon deposits was found to be around 8.5% with the exception of HZSM-5 with the Si/Al ratio of 300,which is much lower. Moreover, the carbon deposits yield dropped gradually with increasing Si/Al ratios of HZSM-5.Calcination of spent catalysts at 600 °C helped to restore the catalytic activity to a large extent despite a relatively lower efficiency of deoxygenation. Results indicated that HZSM-5 with relatively high acidity displayed great catalytic performance.

Is Iba-1 protein expression a sensitive marker for microglia activation in experimental diabetic retinopathy?

AIM:To investigate the changes of Iba-1 and other potential markers for microglia activation in experimental diabetic retinopathy(DR).METHODS:Male Sprague-Dawley rats were rendered diabetes via intraperitoneal injection of streptozotocin.The retinas were harvested at 1 to 24 wk after diabetes onset.Hypoxia-treated mouse microglial cell line(BV2 cells)was employed as the in vitro model to mimic diabetic condition.The expressions of Iba-1,CD11 b,ICAM-1 as well as the inflammatory factors were examined with real-time polymerase chain reaction,Western blot and immunofluorescence both in vivo and in vitro.RESULTS:Compared with age-matched normal control,the number of microglia(Iba-1 positive immunostaining)in diabetic rat retinas was increased from 1 to 24 wk of diabetes,which was most obvious at 12 wk of diabetes.Iba-1 protein expression detected by Western blot was increased slightly in diabetic rat retinas compared with that in age-matched normal control;however,there was statistically significant between two groups only at 2 wk after diabetes onset.The m RNA expression of Iba-1 was decreased significantly at 2 and 4 wk of diabetic rat retinas,and remained unchanged at 8 and 12 wk of diabetes.In BV2 cells,there was no significant change for the Iba-1 protein expression between normoxia and hypoxia groups;however,its m RNA level was decreased significantly under hypoxia.To further characterize microglial activation,F4/80,CD11 b and inflammatory factors were detected both in vivo and in vitro.Compared with normal control,the expressions of F4/80 and CD11 b as well as the inflammatory factors,such as ICAM-1,i NOS,COX2,IL-1βand IL-6,were increased significantly both in vivo and in vitro.CONCLUSION:Iba-1 protein expression might not be a sensitive marker to evaluate the activation of microglia in experimental DR.However,Iba-1 immunostaining,in combination with other markers like CD11 b and ICAM-1,could be well reflect the activation of microglia.Thus,it is of great importance to explore other potential marker to evaluate the activation of microglia.

Energy-Efficient coaromatization of methane and propane

Development of highly effective catalysts for one-stage conversion of methane with high selectivity to valuable products and energy efficiency will provide an efficient way to utilize natural gas and oil-associated gases and to protect environment. In recent years, there have been many efforts on direct catalytic transformations of methane into higher hydrocarbons by feeding additives together with methane under non-oxidative conditions. This paper reviewed the advances in recent research on non-oxidative aromatization of methane in the presence of propane over different modified HZSM-5 catalysts. The thermodynamic consideration, the isotope verification and the mechanism of the activation of methane in the presence of propane are discussed in the paper in detail.

A Convenient Synthesis of Aromatic Fluoride by Thermal Stable Pyridinium Phase-transfer Catalyst

Using 4-Dialkylaminopyridinium salt as a thermal stable phase-transfer catalyst (PTC), the excellent results were obtained in the halogen-exchange fluorination.

A Facile Route to Unsymmetrical Sulfide

Unsymmetrical sulfides can be generated by the reaction of chlorine substituted aromatic compounds in sulfoxide in the presence of fluorine anion in fair yield. A likely mechanism was proposed.