BACKGROUND:In the fluorine-containing acidic environment, it is unclear whether Damon copper- nickel-titanium arch wire can have a corrosion resistance similar to conventional nickel-titanium arch wire and whether copper ion wil affect its corrosion resistance. OBJECTIVE: To evaluate the corrosion resistance of 3M nickel-titanium arch wires and Damon copper-nickel-titanium arch wires in artificial saliva with different fluoride and pH. METHODS:Potentiodynamic polarization curves of 3M nickel-titanium arch wires and Damon copper-nickel-titanium arch wires were measured in four kinds of artificial saliva (pH=7; pH=7, 0.2% fluoride; pH=7, 0.5% fluoride; pH=5, 0.5% fluoride). Then, the corrosion potential, corrosion current density and polarization resistance were acquired, and scanning electron microscope was used for morphological observation after corrosion. RESULTS AND CONCLUSION: In neutral (pH=7) artificial saliva, 0.2% fluoride ions added could shift up the Damon specimen polarization curve, increase the corrosion cerrent density and reduce the polarization resistance (P < 0.05); under the scanning electron microscope, corrosion was observable on the specimen surface. But 3M specimen polarization curve did not move, corrosion current density and polarization resistance substantialy unchanged (P > 0.05), and no significant corrosion was produced. When fluoride concentration was increased to 0.5%, the polarization curves of two kinds of the specimens moved, the corrosion cerrent density increased, the polarization resistance decreased (P < 0.05), and there was significant presence of corrosion on the specimen surface. When pH=5, corrosion phenomenon was more pronounced. These findings suggest that low concentrations fluoride cannot affect corrosion resistance of 3M arch wire, but can reduce the corrosion resistance of Damon arch wire; high concentrations of fluoride and acid can both reduce their corrosion resistance. In addition, the corrosion resistance of 3M arch is stronger than that of Damon arch wire.

As an important kind of plant secondary metabolites and widely distributed in the plant kingdom, triter-penoid saponins have a variety of biological activities. The constitution and content of triterpenoid saponin are deter-mined by some key enzymes and their expressing level in triterpenoid saponins biosynthesis pathway. So, it is very important to illuminate the molecular mechanism of triterpenoid saponins biosynthetic pathway. In recent years, illu-mination of the entire biosynthetic pathway especially the confirmation and cloning of the key enzymes, such as squa-lene synthase, squalene epoxidase, cytochrome P450 monooxygenase and UDP-glycosyltransferase, had become one of the hot spots by many scholars. In this paper, the entire biosynthetic pathway and some kinds of key enzymes in-volved in the synthesis of carbon skeleton, and its oxidation, and glycation were reviewed for further demonstrating the biosynthetic pathway of triterpenoid saponins and providing a theoretical basis for artificial biosynthesis.

Objective To investigate clinical usefulness of intracranial lesions in pre-and post-operation by functional MRI with blood oxygen level dependent(BOLD)technique.Methods Common MRI and Motor hand area functional MRI examinations were performed in 45 patients (fMRI group)with intracranial lesions adjacent to the motor cortex before and after operation. As contrast group, 20 patients with occupying position lesions were made a routine MRI examination without fMRI before surgery. A 1.5 T signa super conducting system was employment (GE company ,America). Results The focal transactivation domain of cerebration was seen on fMRI in all cases of fMRI group. The cortical motor hand area shown displacement in 22 cases with abnormal size and shape and found not displacement in 23 cases. The distribution of transactivation domain was not changed in different disease . There was positive correlation between the distance from lesions to the domains and myodynamia in preoperation(r=0.553,P0.05). Our data indicated that there was negative correlation between the distance and the difference of myodynamia (r=-0.570,P

Objective Compare the curative effect of simply bone grafting with bone grafting, sequentially or simultaneously instrumentation planting in surgical treatment of thoracolumbar spinal tuberculosis,to verify the possibility and curative effect of radical debridement,bone grafting, sequentially or simultaneously instrumentation planting.Methods Twenty-five cases were treated with radical debridement,bone grafting,21 patients with sequentially or simultaneously instrumentation planting.Evaluating the bony fusion rate,correction of deformity and the status of lesion contrastively.Results Forty-three patients were followed-up for an average of 21 monthes,all of them were cured and shown bony union. With instrumentation we got shorter bony union,better correction and no obviously correction lost.Conclusion Radical debridement,bone grafting, sequentially or simultaneously instrumentation planting can offer a complete removal of lesion as well as restruction of spinal stability which make the local immobilization possible.Through this procedure ,early rehabilitation will be possible and the cure rate fo spinal tuberculosis increased.

Objective To observe the effect of levocarnitine and trimetazidine on left ventricular mass index in patients with maintenance hemodialysis (MHD),and to explore the safety and efficacy of the two drugs when used in combination.Methods 48 cases of MHD were randomly divided into control group and treatment group,24 cases in each group.On the basis of routine treatment,treatment group was treated with L -carnitine 1.0g by intravenous, 3 times per week,and trimetazidine tablets 20mg,3 times daily at the end of each dialysis.The control group was only treated with L -carnitine.The course of treatment was 12 months.The left atrial diameter (LAD),left ventricular end diastolic diameter (LVDD),left ventricular end diameter (LVDS),interventricular septal thickness (IvST),left ventricular posterior wall thickness (LVPWt),left ventricular ejection fraction (LVEF),stroke volume (SV),left ventricular mass index calculation were detected and compared before and after treatment in the two groups.Results After treatment,the LAD,LVDd,LVDs,IvST,LVPWt in the control group were (40.25 ±1.73)mm,(51.16 ± 3.17)mm,(32.52 ±2.86)mm,(11.16 ±1.23)mm,(10.23 ±1.19)mm,which were decreased compared with before treatment [(42.63 ±1.82)mm,(53.71 ±3.26)mm,(35.83 ±3.12)mm,(12.51 ±1.39)mm,(11.76 ± 1.37)mm],and the LAD,LVDd,LVDs,IvST,LVPWt in the treatment group were (37.61 ±1.86)mm,(47.53 ± 3.18)mm,(29.71 ±2.93)mm,(10.46 ±1.32)mm,(9.14 ±1.32)mm,which were decreased compared with beforetreatment [(42.89 ±1.91 )mm,(54.18 ±3.29)mm,(35.76 ±3.27)mm,(12.49 ±1.35 )mm,(11.73 ± 1.41)mm](t control group =4.643,2.747,3.831,3.563,4.130,t treatment group =9.702,7.120,6.750,5.209, 6.569,all P <0.05 ),and each index of the treatment group was significantly lower than the control group (t =5.091,3.961,3.362,2.901,3.005,all P <0.05 ).The LVMI of the control group and treatment group was (121.63 ±7.16)g/m2 ,(115.49 ±7.91)g/m2 after treatment,which were decreased compared with before treatment [(127.32 ±7.51)g/m2,(126.87 ±7.28)g/m2 ](t =2.686,5.186,all P <0.05).The EF and SV of the control group were (58.16 ±4.35)%,(43.61 ±4.72)mL after treatment,which were increased compared with before treat-ment[(55.32 ±4.17)%,(40.52 ±4.13)mL](t =2.686,5.186,all P <0.05).The EF and SV of the treatment group were (61.26 ±4.13)%,(46.25 ±4.17)mL after treatment,which were increased compared with before treat-ment[(55.28 ±4.51)%,(40.81 ±4.96)mL](t =4.791,4.113,all P <0.05).After treatment,LVMI in the treat-ment group was lower than that in the control group,SV and EF were higher than those in the control group (t =2.819,2.532,2.053,all P <0.05).Conclusion Compared with single levocarnitine,the therapy of levocarnitine and trimetazidine can better reduce left ventricular mass index in MHD patients and improve the cardiac structure and function,which is safe and effective.

Objective To observe the expression of αA-and αB-crystallin in retina after blue-light exposure.Methods Forty female Wistar rats were divided randomly into 4 groups:control group,and blue-light exposure for 6,12,and 24 hours groups,with 10 rats in each group.The rats in the control group were not intervened.The other three groups of rats were exposed to blue fluorescent lights for 6,12,and 24 hours respcetively.Then the rats were kept in darkness for 12 hours.The globes were enucleated after anaesthesia.The immunohistochemistry and Western blot were performed to detect the expression of αA-and αB-crystallin in retina.Results The absorbance value(A value)of retina αA-crystallin was 1.40573±0.70748 in the control group,and were 4.317 51±0.412 97,7.397 08±1.947 90,9.634 32±2.377 61,respectively in the other 3 groups;the difference among the groups was significant(F=24.569,P<0.001).The A value of retina αB-crystallin is 0.129 36±0.033 93 in the control group,and were 0.507 17±0.117 55,7.345 43±2.292 97,4.042 26±3.890 23,respectively in the other 3 groups;the difference among the groups was significant(F=40.102,P<0.001).The results of Western blot showed that the expression of αA-and αB-crystallin in groups with blue-light exposure was obviously higher than that in the control group.Conclusions Blue light may up-regulate the expression of αA-and αB-crystallin in rats' retina.

Objective To study the effects of sibutramine on the human-ether-a-go-go-related gene (hERG) current in HEK293 cell line that overexpresses hERG potassium channels. Methods HEK293 cell line that overexpresses hERG potassium channels was constructed. Whole cell patch clamp techniques were employed to investigate the effects of sibutratime on Iherg in the cell line. Results Sibutramine reduced hERG current in a concentration-dependent manner:the inhibition rate was (8.82?2.32)%,(26.7?5.78)%,(44.93?4.60)% and (85.22?3.37)% at the dose of 3,10,30 and 100 ?mol/L. IC50 value was 32.66 ?mol/L (n=8). Ⅰ-Ⅴ relationship was inhibited by sibutramine (3,10,30 and 100 ?mol/L) at membrane potentials from -10 mV to +60 mV (step) and from 0 mV to +60 mV (tail) (n=8). Conclusion Sibutramine significantly inhibited Iherg in HEK293 cell line that overexpresses hERG potassium channels in a concentration-dependent manner,which may be a major mechanism of causing QT interval prolongation.

Hand ; Humans ; Reference Standards ; Vibration

10.3969/j.issn.2095-4344.2013.24.018