Objective:To evaluate the effects of surface modified nano titanium-oxide on the mechanical properties of A-2186 silicone elastomers. Methods:Added surface modified nano titanium-oxide into A-2186 silicone elastomers with 0.0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% additions according to the ASTM standard. The mechanical properties of A-2186 silicone elastomer including the tensile strength, the broken elongation, the tear strength and the Shore-A hardness were tested separately. The section of samples were investigated by scanning electron microscope and energy spectrum analysis. Used statistics method to analyse the results. The results were analysed with software EPSS 13.0. Results:With the addition of nano titanium-oxide increasing, the tensile strength, the broken elongation and the tear strength of A-2186 silicone elastomers increased firstly, and then decreased. While the Shore-A hardness of A-2186 silicone elastomers increased gradually. When the addition of surface modified nano titanium-oxide reached to 2.0%, the nano titanium-oxide dispersed well in the base without agglomeration. Under such condition, the A-2186 silicone elastomer showed the best general mechanical properties:the tensile strength was (6.54?0.55) MPa, the broken elongation was 618.00?7.58(%), the tear strength was (16.64?0.52) kN/m and the Shore-A hardness was (31.00?0.79) U. Conclusion:The mechanical properties of A-2186 silicone elastomers are improved most greatly with 2.0% addition of surface modified nano titanium-oxide to the base of A-2186 silicone elastomers.

BACKGROUND:An ideal scaffold material needs appropriate degradation rate and certain mechanical properties, but the traditional colagen sponge scaffold has rapid degradation velocity and low mechanical strength, which is easy to colapse and difficult to maintain its natural form. Traditional cross-linking methods also have the problems of cytotoxicity or colagen denaturation, severely limiting the application of colagen. OBJECTIVE:To design a new cross-linking method for colagen and to optimize the self-assembly process so as to develop a colagen sponge scaffold with good mechanical properties and resistance to degradation. METHODS:Colagens were modified by self-assembly technology to prepare colagen fibrils which were then freeze-dried into fibrilar colagen sponges. Meanwhile, we optimized the conditions of self-assembly by using orthogonal experiment based on univariate analysis of the effect of initial colagen mass concentration, final phosphate concentration and pH value on the conversion yield of colagen self-assembly. RESULTS AND CONCLUSION:We optimized the conditions of self-assembly revealed that the optimum conditions to prepare colagen fibrils were determined as pH=8.0, initial colagen concentration=2 mg/mL, and final concentration of phosphate=15 mmol/L. The results of scanning electron microscope showed that fibrilar colagen sponges were characterized by refined porous structure which was connected by colagen fibrils. In addition, the fibrilar colagen sponges showed better equilibrium-sweling ratio, water retaining property and mechanical strength compared with unmodified colagen spondages (P < 0.05), to solve the problems in rapid degradation.

Background Choroidal neovascularization (CNV) is a serious complication of many fundus diseases.A variety of factors are associated with CNV.Research showed that recombinant human endostatin ( rhendostatin ) can arrest the vascular endothelial growth factor (VEGF) pathway and inhibit the proliferation of endothelial cells and angiogenesis.Objective This study was to observe the inhibition of rh-endostatin on experimental CNV.Methods The CNV animal models were created by Argon laser with the wavelength 532 nm to irradiate the inferior retina away optical disc 1-2 DD for 25 spots in 32 eyes of 16 chinchilla rabbits.The laser parameters were as follows:power 800 mW,spot diameter 75 μm and time shutter 50 ms.The models were then divided into model control group and rh-endostatin group.Rh-endostatin was intravitreously injected via scleral incision in 16 eyes of 8 model rabbits at 1 week after photocoagulation.Fundus fluorescein angiography (FFA) and optical coherence topography(OCT) were performed at 1,2,4 weeks after photocoagulation respectively.The eyeballs were enucleated and the retinal sections were prepared for the histopathologieal examination,and the contents of VEGF and pigment epithelial derived factor(PEDF) in rabbit vitreous,and blood serum were detected by ELISA at 2,4 weeks after photocoagulation.Results Retinal edema and exudes were seen in 1 week and scarring in 4 weeks after photocoagulation.In rh-endostatin injection group,the hyperfluorescence masses were seen in the background phase and early arterial phase in 42％ (84/200) of spots in the first week.The fluorescence leakage was decreased in the rh-endostatin injection group compared with control group in the second week and ceased at the third week on the FFA after injection.Variety forms of hyperreflective zones were found below the retinal pigment epithelium on the seventh day after photocoagulation.But the partial vessel occlusion and fibroplasias were identified in the rh-endostatin injection group in the third week by the OCT.The histopathological examination showed that the morphological abnormality was mild in the rh-endostatin injection group in comparison with model group.The serum PEDF concentration was significantly elevated but the VEGF/PEDF values in vitreous and serum were declined in rhendostatin injection group compared with model group (P ＜ 0.0 1 ).Conclusions Argon laser photocoagulation could induce the experimental CNV in chinchilla rabbit.Intravitreous injection of rh-endostar can effectively inhibit laser-induced CNV in rabbit.

Objective To investigate the correlation between quantitative parameters with contrast-enhanced ultrasound-power Doppler(CEUS-PD) and mierovessel density (MVD) in hepatoeellular carcinoma (HCC). Methods Thirty-four cases with HCC underwent CEUS before operation. The satisfactory images were selected through CEUS-PD and analyzed with computer to calculate mean color vessel density(MCVD). The blood flows of focal lesions were graded into 0-Ⅲ based on the numbers of color vessels with CEUS-PD. The correlation between those parameters and MVD counted with immunohistochemistry was analyzed after operation. Results In 34 cases with HCC, the MCVD of focal lesions with CEUS-PD was 0. 17±0.09, the pathologic MVD was (62.59 ±23.96)/400 × after operation. The MCVD was positively correlated to MVD( r = 0. 56, P <0.05). In 34 cases HCC,3 cases were in grade Ⅰ , 12 cases were in grade Ⅱ , 19 cases were in grade Ⅲ. There was significant differences in pathologic MVD of every grade ( F = 8.06, P <0.05). But there was no linear tendency in the grades( F = 7.57, P<0. 05). Conclusions In focal lesions of 34 HCC, MCVD calculated with CEUS-PD was positively correlated to pathologic MVD. It can be used to evaluate tumor blood perfusion exactly before operation.

Vascular endothelium plays an important role in regulating vascular homeostasis. Over the past years, it has become clear that endothelial dysfunction is a key event of pathophysiological changes in the initiation and progression of injuries induced by extreme environmental factors. The present review summarizes current understanding of vascular endothelial dysfunction induced by hypoxia, cold and heat, and provides the information for prevention and treatment of environmental exposure injuries.
Endothelium, Vascular ; physiopathology ; Environment ; Humans ; Hypoxia ; physiopathology ; Temperature ; Vascular System Injuries

Objective To evaluate the value of echocardiography on the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC),and to improve the diagnositic accuracy of ARVC by echocardiography.Methods According to the 2010 European Heart Association guideline,twenty-one patients with ARVC were diagnosed from September 2003 to June 2014.The patients were divided into four groups (confirmed,suspiciously diagnosis,miss diagonisis,misdiagnosis) and the echocardiographic features were retrospectively analyzed including the right ventricular (RV) movement,the diameter of RV outflow tract (RVOTd),fractional area change of RV (RVFAC),the severity of tricuspid regurgitation (TR) and peak pulmonary artery systolic pressure (PASP).Results Of 21 patients,15 (71.4％) were confirmed by echocardiography,which had the typical ARVC echocardiographic features including the hypokinetic,akinetic or aneurysm of RV,dilation of RVOTd [mean RVOTd (40 ± 3)mm],and RV FAC＜33 ％ [mean (21 ± 7)％].TR were noticed in all the 15 patients but the PASP were normal [mean (27 ± 9)mmHg,1 mmHg =0.133 kPa].Three (14.3％) were suspiciously diagnosed which had the RV wall hypoakinetic,1 with pure RVOTd dilation and 2 with RV and RVOTd dilation,all 3 patients had mild TR,33％＜RVFAC ≤40％ and PASP were in normal range.Two patients had normal echocardiography which was miss diagnosed,one patient was misdiagnosed as dilated cardiomyopathy.Conclusions The different stages of ARVC patients had different echocardiographic features,the patients were easily diagnosed when the ARVC patients in RV failure stage.But for the early and late stage,the diagnosis should combine the clinical manifestation and other imaging facilities to avoid miss diagnosis and misdiagnosis.

The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ) by high performance liquid chromatographic (HPLC) methods,which included ibuprofen (Cl),ketoprofen (C2),nitrendipine (C3),nimodipine (C4),felodipine (C5),omeprazole (C6),praziquantel (C7),propranolol hydrochloride (C8),atenolol (C9),sulpiride (C10),clenbuterol hydrochloride (C11),verapamil hydrochloride (C12),and chlorphenamine maleate (C13).The mobile phase consisted of isopropanol and n-hexane.The detection wavelength was set at 254 nm and the flow rate was 0.7 mL/min.The enantiomers separation of these thirteen racemates on chiralpak OD column and chiralpak OJ column was studied,while the effects of proportion of organic additives,alcohol displacer and temperature on the separation were studied.And the mechanism of some of racemates was discussed.The results indicated that thirteen chiral drugs could be separated on chiral stationary phase of cellulose ramification in normal phase chromatographic system.The chromatographic retention and resolution of enantiomers could be adjusted by factors including column temperature and the concentration of alcohol displacer and organic alkaline modifier in mobile phase.It was shown that the resolution was improved with reducing concentration of alcohol displacer.When concentration of organic alkaline modifier was 0.2％ (v/v),the resolution and the peak shape were fairly good.Most racemates mentioned above had better resolution at column temperature of 25 ℃.When racemates were separated,the temperature should be kept so as to obtain stable separation results.

Objective To investigate the methods of reducing radiation dose in CT coronary angiography through optimizing individualized scan dosage protocol.Methods Two hundred patients (group A)underwent coronary CTA examination which was performed with fixed 120 kV and variable mA according to their BMI.The mA was set as 150-300 mA(BMI ＜ 18.5 kg/m2),300-500 mA (18.5 kg/m2 ≤ BMI ＜ 25.0 kg/m2),and 500-800 mA(BMI ≥ 25.0 kg/m2).When all examinations were finished,a linear regression was employed to analyze the correlation between mA and BMI,body surface(Suf),image noise(SD)respectively.The results of the analysis were used to formulate a regression equation,which was further used to establish a table list for quick search on how much mA that individualized coronary CTA scan would need.Another 200 patients(group B)enrolled for the individualized scan were scanned under new protocol that previous study established.The tube voltage was 100 and 120 kV.The tube current was variable according to the data in the table list.One-way ANOVA and Kruskal-wallis H test were used for statistics.Results Regression equation between mA and BMI,Suf,SD was:mA =17.984 × BMI + 169.149 × Suf-2.282 × SD-361.039.The SD(group A:32.08 ± 5.80,group B:28.60±4.47),dose index volume(CTDIvol)[group A:(41.97 ± 11.37)mGy,group B:(33.18±10.07)mGy],effective dose(ED)[group A:(10.91 ±3.07)mSy,group B:(8.83 ±2.72)mSv]had significant differences between the two groups(F =43.45,63.71,49.07 respectively,P ＜0.01 for all).The SD and ED results obtained in group B were better than those in group A.Conclusion Better performances were obtained when BMI combined Suf was used as a new individualized protocol than when BMI was used only,which means good image quality and lower radiation dosage in coronary CTA examination.

Objective To find out the present situation of hepatitis B infection or immunity in Tianjin city,and to provide the scientific basis for the hepatitis B control and prevention.Methods 2 594 samples were selected with the methods of different proportionate stratified and cluster sampling,and the hepatitis B infection markers were detected by ELISA.Results The positive rates of HBsAg,anti-HBs,anti-HBc and HBV were 2.62％,46.72％,10.60％ and 51.54％.Conclusion Compared with the results in 1992,the positive rates of HBsAg,anti-HBc and HBV were decreased significantly,while the positive rate of anti-HBs increased significandy,which ascribed to the comprehensive measure with the vaccination against hepatitis B as a main strategy for control hepatitis B.

Objective To investigate the effect of heat stress on organ indices, intestinal morphology, gastric mu-cosal HSP70 mRNA expression and glucose metabolic hormones in mice.Methods A single-factor experiment was de-signed for the present research.Eighteen KM mice of the similar age and weight were randomly divided into control group and heat stress group.The weight of the heart, liver, spleen, lung and kidney, as well as the expression of HSP70 mRNA in the mouse gastric mucosa were measured.The plasma concentration of insulin and glucagon, the villus height and crypt depth of the duodenum and jejunum were detected.The histological changes of the liver, duodenum and jejunum were also examined.Results There was no effect of heat stress on the organ indices.It significantly increased the expression of HSP70 mRNA in the gastric mucosa, reduced the plasma insulin level and caused serious injury to the liver, duodenum and jejunum in the mice.Conclusions Heat stress does not significantly affect the organ indices in mice, but can significantly increase the expression of HSP70 mRNA in the gastric mucosa, cause apparent damages in the liver, duodenum and jeju-num, reduce the villus height, crypt depth and villus height/crypt depth ratio of the duodenum and jejunum, and also de-crease the blood insulin concentration in the mice.