Hydroisomerization of long chain n-alkanes has been playing an important role in the petroleum industry, in which heavy distillate and residue are converted into value-added products such as gasoline, jet fuel, other middle distillates and lubricant oils. Herein, 10-ring zeolites, including ZSM-22, ZSM-23, ZSM-35, and ZSM-48 were studied for the process. ZSM-35 and ZSM-48 are relatively less studied zeolites as hydroisomerization reaction catalysts though they are expected to display interesting shape selective properties. A higher conversion was obtained over Pt-ZSM-35 and a higher selectivity was obtained over Pt-ZSM-23 at low temperature and short contact time, and a higher selectivity was obtained over Pt-ZSM-48 at high temperature and long contact time, while the mixed catalysts displayed interesting conversion and selectivity. Small differences in the channel system have a notable influence on the product distribution of hexadecane hydroisomerization over 10-ring zeolites. A combination of the evidence of no absence of multibranched products and the length of hexadecane molecular could infer that hexadecane hydroisomerization includes a pore mouth reaction mechanism.

AIM:To investigate the expression of three types of mucin (MUC1, MUC2, MUC5AC) and E-cadherin in human gastric carcinomas and their clinical significance. METHODS:Ninety-four gastric cancer specimens were classified according to WHO criteria and detected by immunohistochemical assay of expression of mucins and E-cadherin. RESULTS:The positive expression rates of MUC1, MUC2, MUC5AC and E-cadherin were 82% (77/94), 84% (79/94), 40% (38/94) and 56% (53/94) respectively. MUC1 expression was significantly correlated with the types of cancer (the positive rates of MUC1 in well and moderately differentiated tubular adenocarcinoma, poorly differentiated adenocarcinoma, signet-ring cell carcinoma and mucinous carcinoma were 91%, 87%, 71%, 71%, respectively, P<0.05), age of patients (the positive rates of it among the people who are younger than 40 years, between 40-60 years and over 60 year were 74%, 81%, 89%, P<0.05), lymph nodes involvement (the positive rates in the non-interfered group and the interfered group were 78%, 85%, P<0.05) and tumor size (the positive rates in the tumors with the size less than 3 cm, 3-6 cm and larger than 6 cm were 69%, 92%, 69%, P<0.05); MUC2 expression was significantly associated with types of cancers and had the strongest expression in mucinous carcinomas (the positive rates of MUC2 in well and moderately differentiated tubular adenocarcinoma, poorly differentiated adenocarcinoma, signet-ring cell carcinoma and mucinous carcinoma were 94%, 70%, 81%, 100%, P<0.05), but it had no obvious relation to age, gender, tumor location, lymph nodes involvement, depth of invasion and metastasis to extra-gastric organs (P>0.05); MUC5AC expression was not related to any of the characteristics investigated except that it had relation to gender, whereas MUC5AC showed the tendency to higher expression in less invasive lesions and lower expression in advanced stage cancers (P>0.05); No significant difference was found for E-cadherin expression. There were strong positive relationships between the expression of MUC1 and E-cadherin, MUC2 and E-cadherin, MUC1 and MUC2 (R = 0.33, R = 0.22, R = 0.32, respectively, P<0.05). According to the COX proportional hazards model, older patients, involvement of lymph nodes, different types of gastric cancer and MUC2 expression were significantly associated with poorer outcome of gastric carcinoma patients (β = 0.08, β = 3.94, β = 1.33, β = 0.75, respectively, P<0.05).CONCLUSION: MUC1 and MUC2 are good markers of different types of gastric cancer. MUC2 is especially a good marker of mucinous carcinoma. MUC1, MUC2 may interfere with the function of E-cadherin in gastric carcinomas, and have synergic effect on progression of gastric cancers.Zhang HK, Zhang QM, Zhao TH, Li YY, Yi YF. Expression of mucins and E-cadherin in gastric carcinoma and their clinical significance.

The pyrolysis reactivity and kinetic characteristics of Tumuji oil sand from Inner Mongolia were investigated at heating rates of 5, 10, 20, and 40 °C/min in a thermogravimetric analyzer. The kinetic parameters of pyrolysis at different heating rates were determined and compared on the basis of a first-order reaction model. The effects of the temperature and pressure on conversion, liquid (oil) and gas yields, and product composition of Tumuji oil sand pyrolysis were further studied in a fixed bed reactor. The results show that all of the conversion and liquid and gas yields increase with an increasing temperature and tend to be constant after temperature more than 520 °C. Increasing pressure will decrease the conversion and yield of pyrolysis. The main component in the liquid product is saturates, which has a higher content than that in the oil sand sample. The gaseous products consist of H2, CO, CO2, CH4, C2H4, and C2H6. With an increase of the temperature, the CO2 content decreases but the contents of other species increase.

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