Objective To estimate the marginal value of the chemical oxygen demand (COD) in drinking water by evaluation of uncertainty. Methods According to Evaluation and Expression of Uncertainty in Measurement (JJF1059-1999), analysis of measure uncertainty of the chemical oxygen demand determined by acidic potassium permanganate titrate prescribed in Sanitary Standards for Drinking Water (2001) was conducted. Results The type A relative standard uncertainty was 0.584%, type B was 0.781%, in which the sub-item uncertainty led by using 25 ml burette was 0.708%, the water sample volume was 0.056%, the adjusted potassium permanganate standard solution was 0.325%; the relative combined standard uncertainty was 0.975%, the expanded uncertainty was 1.95%. Conclusion According to the result of the uncertainty (3.08?0.06) mg/L, COD in the polluted sample exceeds the limit, the use of 25 ml burette produced the most contribution to the uncertainty.

The gene encoding the VP28 envelope protein of White spot syndrome virus (WSSV)was cloned into expression vector pET-30a and transformed into the Escherichia coli strain BL21.After induction,the recombinant VP28 (rVP28) protein was purified and then used to immunize Balb/c mice for monoclonal antibody (MAb) production.It was observed by immuno-electron microscopy the MAbs specific to rVP28 could recognize native VP28 target epitopes of WSSV and dot-blot analysis was used to detect natural WSSV infection.Competitive PCR showed that the viral level was approximately 104 copies/mg tissue in the dilution of gill homogenate of WSSV-infected crayfish at the detection limit of dot-blot assay.Our results suggest that dot-blot analysis with anti-rVP28 MAb could rapidly and sensitively detect WSSV at the early stages of WSSV infection.

Objective To compare the clinical choosing principles of sedated colonoscopy with con-ventional colonoscopy. Methods Outpatients who were willing to accept colonoscopy with or without seda-tion were prospectively recruited,which were assigned to sedated colonoscopy group(n=362)and conven-tional colonoscopy group(n=323). All patients and endoscopists were asked to answer a self-administered questionnaire. The colonoscopy completion,operation time,procedure-related discomfort,and questionnaire results of the two groups were compared and statistically analyzed. Results The completion rate was 98. 9%in the sedated colonoscopy group(358/362)and 89. 8% in the conventional colonoscopy group(290/323) ( P=0. 337 ). The operation time of sedated and conventional group were( 5. 60 ± 3. 25 ) minutes and (7. 71 ± 5. 70)minutes respectively(P<0. 001). And the average cost was CNY 886. 54 per patient in se-dated group and CNY 386. 00 per patient in the conventional group. Patient satisfaction score of conventional group and sedated group were 4(3-4)and 3(2-3)points(P<0. 001),while endoscopist satisfaction score was 4(3-4)and 4(4-4)(P<0. 001). A total of 354 patients(97. 79%)in the sedated group and 225 pa-tients(69. 66%)in the conventional group showed willingness to repeat the identical colonoscopy( P <0. 001). Patients who were male(P=0. 035),having no past abdominal operations(P<0. 001),or no ab-dominal pain during colonoscopy( P =0. 015 )in the conventional group preferred to repeat conventional colonoscopy. Conclusion Although the examination time of conventional colonoscopy is longer than sedated colonoscopy,it could reduce anesthesia risk and the cost. Conventional colonoscopy remains an irreplaceable examination of colorectal diseases in developing countries. Physicians should not only focus on patients'com-fort during endoscopy,but also help patients make a decision based on their actual situation and endoscopic indications to make the best of medical resources.