Objective To observe the removal of Cr(Ⅵ) and effects of some factors in solution on Cr(Ⅵ) with zero valent iron(ZVI).Methods A certain amount ZVI were added in a 50 ml solution with Cr(Ⅵ),the effects on removal ratio were observed when the initial Cr(Ⅵ) concentration was 5,10,20 and 30 mg / L,temperatures was 5,15,25 and 35 ℃,the ZVI dosage was 0.25,0.5,0.75,1.0,1.25 and 1.50 g and anions such as Cl-,NO3-,SO42-,CO32-and PO43-.The removal ratio of Cr(Ⅵ) was evaluated by Cr(Ⅵ) concentration difference pre and post-treatment with ZVI.Results Cr(Ⅵ) could be removed effectively with ZVI and removal ratio of Cr(Ⅵ) could reach over 90% in 5 min,the Cr(Ⅵ) concentration of the solution could meet the requirement of GB5749-2006 Sanitary Standard for Drinking Water Quality [ Cr(Ⅵ) concentration≤0.05 mg/L].The best reaction conditions was 35 ℃,pH=2,dosage of ZVI =1.0 g.Conclusion Cr(Ⅵ) can be removed by ZVI in solution,the removal ratio can be impacted by some factors such as pH value,Cr(Ⅵ) initial concentration,temperature.

Objective: To investigate the acidogenicity and aciduric ability of Streptococcus mutans isolated from the children with different caries susceptibility.Methods: The acidogenic and aciduric ability of Streptococcus mutans strains isolated from children was investigated.Acidogenicity ability was compared among high caries-susceptible group,middle caries-susceptible group and caries-free group.Results: The acidogenicity and aciduric ability of Streptococcus mutans isolated from the high caries-susceptible children and middle caries-susceptible group were significantly higher than that isolated from caries-free group(P

Objective: To investigate the inhibitory effect of Flu or Protector on the demineralization of bovine enamel caused by some beverages. Methods: Forty bovine teeth were equally divided into experimental and control groups, each of them were subdivided into two groups. The enamel sp ecimens of the experimental group were pretreated with Fluor Protector and then exposed to carbonated drinks and fruit juice respectively,the enamel specimens o f control group were exposed to beverages directly. All the enamel specimens wer e exposed to beverages 5 times a day and for 5 minutes each time. After 7- day exposure,the concentration of calcium and phosphate in the beverages were measu red by EL 312e Micro-Plate. Results: The concentration of calci um and phosphate in the corresponding beverage of experimental group was lower t han that in control group in the same expossure time(P0.05).Conclusions: Fluor Protector can inhibit the demineralization of bovin e enamel caused by beverages.The inhibitory effect of Fluor Protector decreases as the exposure time prolonges.

0.05). The average amount of ammonia emission was 0.012%, 0.024% and 0.081% at pH values of 9, 11 and 13 respectively. Ammonia emission increased with the increasing pH values, especially for those admixtures containing carboxylate. Conclusion Ammonia emission from concrete admixtures sold in Lanzhou exceed the standard in different degree.Higher pH value may accelerate the ammonia emission from concrete admixtures and cause higher concentration of ammonia in indoor air.

Objective To explore the effects of temperature and relative humidity on radon exhalation rate of glazed tile in the hermetic environment. Methods Ordinary glazed tile was used as experimental object to detect radon concentration with Model 1027 continuous radon monitor in a 0.25 m3 simulation chamber at different temperature and humidity,and then calculated the radon exhalation rate. Results In reasonable range,a cubic correlation between radon exhalation rate(ER) and relative humidity(RH) expressed as ER=0.000 2RH3-0.040 2RH2+2.623 9RH-32.303(R2=0.986 6)was found; a cubic function relationship between radon exhalation rate(ER) and temperature(t) expressed as ER=-0.022 5t3+2.016 5t2-58.748t+565.05(R2=0.969 8)was also observed. Conclusion Environmental temperature and relative humidity have great effects on radon exhalation rate of glazed tile.

To investigate the effect of casein phosphopeptide-amorphic calcium phosphate(CPP-ACP) on the growth of Lactobacillus fermentum and to evaluate the possibility of CPP-ACP as a biological anticariogenic agent. Lactobacillus fermentum was inoculated in BHI with different concentrations of CPP-ACP and grew in anaerobic condition at 37 ℃ for 48 h. Used MTT method to evaluate the effects of CPP-ACP on the growth of Lactobacillus fermentum. CPP-ACP inhibited the growth of Lactobacillus fermentum effectively. With the concentration of CPP-ACP increasing, the values of A(550 nm) decreased. It was found that CPP-ACP had inhibitory effect on the growth of Lactobacillus fermentum, the inhibitory effect increased with CPP-ACP concentration.

Objective To summarize the experience of great saphenous vein (GSV) harvesting using multiple interrupted cutaneous incisions and retrospectively compare the clinical results with those using traditional single long incision. Methods One hundred and forty-nine patients for initial elective coronary artery bypass grafting underwent GSV harvesting by either interrupted incisions (Group A, n=108) between August 2004 to October 2005 or traditional technique (Group B, n=41) between February 2004 and July 2004, respectively. The Length of GSV harvested, total incision length, time of harvesting, and complication rate were compared between the two groups. Results There were no statistical differences in the age, sex, length of GSV harvested, and macroscopic GSV quality between the two groups. Short- or long-term complications relating to the quality of venous grafts occurred in neither groups. As compared with the Group B, the Group A presented significantly longer time for GSV harvesting (49.3?6.6 min vs 29.1?5.4 min; t=17.490, P=0.000), shorter incision length (17.8?3.2 cm vs 43.1?4.9 cm; t=-36.878, P=0.000), and lower wound-related complication rate [9.3% (10/108) vs 22.0% (9/41); ?2=4.303, P=0.038]. The time for donor site manipulation was slightly increased in the Group A (62.4?8.7 min vs 59.8?6.9 min; t=1.718, P=0.088). Conclusions GSV harvesting using multiple interrupted incisions requires more complicated and difficult techniques than using a single long incision, but it is less invasive and produces superior patient satisfaction and better cosmetic outcomes.

Objective To investigate the quantity of formaldehyde released by artificial wood-based boards sold in Lanzhou. Methods Formaldehyde quantity released by three kinds of artificial wood-based boards(42 samples) were determined with desiccator method. Results Among 42 samples, 9 artificial wood-based boards were E1-level (21.4%), 20 E2-level (47.6%), the others disqualification (31%). A significant difference (0.01

Objective To evaluate the relationship between mRNA and protein expression of HtrA and Streptococcus mutans i-solated from the children with different caries experience and to provide the theoretical and experimental basis on prediction of dent-al caries in deciduous teeth .Methods The strains of Streptococcus mutans isolated from children with different carious experiences in the preliminary experiments were divided into three groups :high caries-susceptible group ,middle caries-susceptible group ,caries-free group .All strains were reanimated on the agar plate of MS ,and after smear pure culture examination ,typical bacteria were in-cubated in BHI ,then purified nucleic acid and extracted all the RNA of streptococcus mutans by reverse transcription PCR and de-tected it by agarose gel electrophoresis integrality .Synthetic cDNA and take further PCR amplification with cDNA products .Ob-serve records results by Gel imaging system .HtrA of target gene and electrophoresis image were gray scan by Gel quantitative soft-ware Gel-Pro analyzer 4 .0 was used to analyze relative expression value of gene .After purifying protein ,collected total protein of Streptococcus mutans strains by Western Blot method ,then tested the concentration of total protein sample .The results of Chemilu-minescence imaging were scanned into computer by Bio-Rad analyzing system ,calculated the gray value by software Quantity One 4 .4 .0 which showed the relative expression level of protein .Results There were significant differences in HtrA mRNA and protein expression of different Streptococcus mutans isolated from the children with different caries susceptibility .high caries-susceptible group> middle caries-susceptible group> caries-free group (P< 0 .05) .Conclusion There were significant differences in HtrA mRNA and protein expression of different Streptococcus mutans isolated from the children with different caries susceptibility .The higher caries susceptibility the group was ,the more HtrA mRNA and protein the strain express .

Objective To explore a method to culture human aortic valvular interstitial cells and identify the phenotypes,to establish the cell model which would be used to study aortic valve diseases in vitro.Methods Normal aortic valves of the patient with acute Stanford A aortic dissection in Peking Union Medical College Hospital were preserved during the surgical operation.Human aortic valvular interstitial cells were isolated and amplified in vitro by modified collagenase digestion method.The cell phenotype was identified by the immunofluorescent staining.Results Human aortic valvular interstitial cells could be successfully isolated and amplified in vitro by modified collagenase digestion method,identified by positive staining of Vimention and α-SMA.Conclusions The cell model of human aortic valvular interstitial ceils could be successfully established in vitro by modified collagenase digestion method.The cell phenotype identification proved to meet the experimental requirements.So it could provide cellular foundations for the study of pathogenesis of degenerative aortic valve disease.