Expression, purification and characterization of a phyA(m)-phyCs fusion phytase

The phyAm gene encoding acid phytase and optimized neutral phytase phyCs gene were inserted into expression vector pPIC9K in correct orientation and transformed into Pichiapastoris in order to expand the pH profile of phytase and decrease the cost of production. The fusion phytase phyAm-phyCs gene was successfully overexpressed in P. pastoris as an active and ex-tracellular phytase. The yield of total extracellular fusion phytase activity is (25.4±0.53) U/ml at the flask scale and (159.1±2.92) U/ml for high cell-density fermentation, respectively. Purified fusion phytase exhibits an optimal temperature at 55 ℃ and an optimal pH at 5.5～6.0 and its relative activity remains at a relatively high level of above 70% in the range of pH 2.0 to 7.0. About 51% to 63% of its original activity remains after incubation at 75 ℃ to 95 ℃ for 10 min. Due to heavy glycosylation, the expressed fusion phytase shows a broad and diffuse band in SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). After deglycosylation by endoglycosidase H (EndoHf), the enzyme has an apparent molecular size of 95 kDa. The characterization of the fusion phytase was compared with those of phyCs and phyAm.     

The Juvenile Victimization Questionnaire: reliability, validity, and national norms

OBJECTIVE: To assess the utility and performance of the 34-item Juvenile Victimization Questionnaire (JVQ) in eliciting the recent victimization experiences of a national sample of children ages 2-17. METHOD: The JVQ was administered in a national random digit dial telephone survey about the experiences of 2,030 children. The experiences of children 10-17 years old were assessed through youth self-report on the JVQ, and the experiences of children 2-9 assessed through JVQ caregiver proxy report. RESULTS: Large numbers of recent victimizations were disclosed using the JVQ (71% of the sample reporting at least one victimization in the last year, with an average of 2.63 victimizations per child). There were few indicators of respondent confusion and little resistance to even the most sensitive questions. In a test of construct validity, endorsements of JVQ items correlated well with measures of traumatic symptoms. The instrument showed adequate test-retest reliability in a 3 to 4 week re-administration. Large numbers of victimizations were reported across the spectrum of ages, and there were no major discontinuities between the self-reports and proxy reports, suggesting that caregivers provided generally adequate and comparable information to child self-reports about the experiences of children under the age of 10. CONCLUSION: The JVQ has potential for use in future epidemiological research as well as clinical evaluation concerning the victimization of children.     

理想破灭

伊凡·斯捷巴诺维奇·罗果夫去看最后一场电影,突然看见路上有一枚十戈比银币,立即捡起来放入口袋。他刚要继续赶路,脑中泛起一个念头:是否应该在这儿再找找呢?也许钱币像蘑菇一样成堆相偎着。罗果夫开始仔细察看,他兜了一圈又发现一枚(比第一次拾到的十戈比银币脏些),他满意地笑笑,用袖子擦擦银币随之放入口袋,仿佛存入储蓄罐似     

货币问题

本书为你再现了美国历史上惊心动魄的货币贵族为了争夺货币控制权而上演的持续百年的没有硝烟的战争。在美国的发展史上,有一个问题一百多年来一直困扰着一代又一代的政客和他们的经济智囊,政党的兴旺衰败以及政客们的得势没落都与之命运攸关。做对了,你将得到丰厚的回报;相反,等待你的只有灭亡。没有哪个问题会像它一样,始终如一地、预示性地同人们的生活密切相关。