Based on the analysis of the influence of the valve pivot distance on the performance of mechanical heart valve (MHV), such as the valve opening and closing features, flow field characteristics and the valve assembly properties, value constraints of the valve pivot distance were established, and the reasonable valve was obtained by means of the finite element method. It can be shown that the central flow characteristics of the valve could be enhanced with the increasing of the ratio of pivot distance to valve inner diameter, but the plastic deformation of the ring could be liable to occur in the MHV assembly process. It is proved that the valve of specifications can be designed in similar ratio of pivot distance to valve inner diameter according to the result of the valve performance experiment.
Heart Valve Prosthesis ; Heart Valves ; Prosthesis Design

Objective To evaluate the clinical effect of emedastine difumarate eye drops combined with pranoprofen eye drops on histamine (HA), eosinophil cationic protein (ECP), leukotrienes B4(LTB4) and, IgE levels of allergic conjunctival and provide reference for clinical diagnosis and treatment.Methods 76 cases of patients with allergic conjunctivitis were randomly divided into control group and experimental group , control group were treated with fumaric acid emedastine eye drops, experimental group were treated with fumarate emedastine combined with pranoprofen eye drops, and then compare the efficacy and serum ECP, HA, LTB4 and IgE levels between two groups before and after treatment of the symptoms and signs score . Results The total efficacy of experimental group was significantly higher than that in control group (94.70%vs.81.60%)(P<0.05).The serum ECP, HA, LTB4 and IgE levels of experimental group were significantly lower than those in control group(P<0.05).Conclusion The emedastine difumarate combined with pranoprofen eye drops in the treatment of allergic conjunctivitis is better than single medication, and ECP, HA, LTB4, IgE significantly decrease.

The possibility of polyoxymethylene (POM) as heart valve leaflet material was investigated by comparing the hemocompatibility with that of 316L stainless steel and low-temperature isotropic pyrolytic carbon (LTIC). Surface hydrophobicity was characterized by water contact angle measurement. Platelet adhesion, APTT/PT/TT and hemolysis rate tests were applied for evaluating hemocompatibility. The results showed that POM was hydrophobic and had a low hemolytic rate, adhesion amount and activation degree of platelets on POM surface were less than 316L stainless steel, and was similar to LTIC. This research pointed out potential application of POM as heart valve leaflets.
Biocompatible Materials ; chemistry ; Blood Platelets ; Carbon ; chemistry ; Heart Valve Prosthesis ; Heart Valves ; Humans ; Platelet Adhesiveness ; Resins, Synthetic ; chemistry ; Stainless Steel ; chemistry

The rutile structure titanium oxide (Ti-O) film was prepared on the pure titanium material TA2 (99.999%) surface by the magnetic filter high vacuum arc deposition sputtering source. The method can not only maintain the material mechanical properties, but also improve the surface properties for better biocompatibility to accommodate the physiological environment. The preparation process of the Ti-O film was as follows. Firstly, argon ions sputtered to the TA2 substrate surface to remove the excess impurities. Secondly, a metal ion source generated Ti ions and oxygen ions by the RF discharge. Meanwhile a certain negative bias was imposed on the sample. There a certain composition of Ti-O film was obtained under a certain pressure of oxygen in the vacuum chamber. Finally, X-ray diffraction was used to research the structure and composition of the film. The results showed that the Ti-O film of the rutile crystal structure was formed under the 0.18 Pa oxygen partial pressure. A Nano scratch experiment was used to test the coating adhesion property, which demonstrated that the film was stable and durable. The contact angle experiment and the platelet clotting experiment proved that the modified surface method had improved platelet adhesion performance, and, therefore, the material possessed better biocompatibility. On the whole, the evaluations proved the modified material had excellent performance.
Heart Valves ; Heart, Artificial ; Ions ; Materials Testing ; Oxygen ; Surface Properties ; Titanium ; X-Ray Diffraction

Objective To evaluate the diagnosis and therapy of solid pseudopapillary tumor of the pancreas (SPTP).Methods From January 2006 to October 2011,the clinicopathological data of 24 SPTP patients diagnosed and surgically treated at Tianjin Medical University Cancer Hospital were analyzed retrospectively.Results There were 22 women and 2 men,the median age was 27.5 years old,with a range from 12 to 51 years.The most common tumor localization were at the head of the pancreas ( 11 patients,45.7％ ),followed by the body (5 patients,20.8％ ),the tail (4 patients,16.7％ ),the body and the tail (3 patients,12.5％ ) and the neck (one patient,4.2％ ).Clinical symptoms were nonspecific and the preoperative diagnosis of SPTP depended on imaging study such as ultrasonography,CT and MR.All patients were treated surgically and the correct diagnosis was made according to pathology after surgery.In a follow-up ranging from 2 to 55 months( median 27.2 months),23 cases were alive with no evidence of disease recurrence,one patient was alive with tumor recurrence.Conclusions SPTP was a less common neoplasm with low-grade malignancy,occurring mainly in young women.Complete tumor resection results in satisfactory prognosis.

OBJECTIVE:To establish a pharmacy online to offline (O2O) platform service quality evaluation model,and to provide reference for platform operators to improve the service quality. METHODS:Using SERVQUAL scale,combining the situa-tion of pharmacy O2O platform development in China,the reliability,safety and aspects of O2O platform were analyzed to sum up primary evaluation index of pharmacy O2O platform service quality. Based on this,the expert interviews questionnaire was de-signed. According to the questionnaire results,indicators were modified and empowered to construct the pharmacy O2O platform service quality evaluation model;the reliability and validity of model were validated. RESULTS & CONCLUSIONS:According to the connotations of each dimension analysis in the SERVQUAL scale and expert interview results of pharmacy O2O platform ser-vice quality,pharmacy O2O platform service quality evaluation model is constructed,including five indicators as“reliability”“se-curity”,and 18 secondary indexes as the“number of platform pharmacy”“pharmacy qualification show”“pharmacy type”. The re-sults of model index reliability and validity verification show that model construction is reasonable and can provide reference for platform operators improving service quality. Follow-up research should give full consideration to the Chinese consumer behavior habits,personal preferences and other factors to build more suitable pharmacy O2O platform service quality evaluation model in China.

A sensitive colorimetric method for the detection of copper ions (Cu2+) was developed based on the surface modification of silver/platinum nanoclusters (Ag/Pt NCs) and regulation of peroxidase-like activity. It was found that 3-mercaptopropionic acid (MPA) could inhibit the catalytic ability of Ag/Pt NCs; however, it lost the inhibition toward catalytic ability of Ag/Pt NCs after oxidized by oxygen through the catalysis of Cu2+. On the basis of this, a colorimetric method was developed for the detection of Cu2+ through measuring the colorimetric signal variation of the TMB-H2O2 reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions. The linear range was 10-100 nmol/L and the detection limit was 5.0 nmol/L (3σ). The above method was also applied to detect real water samples and spiked samples, and the results demonstrated that this method was simple with low cost.

Objective To explore the occurance and risk factors of recurrence and metastasis of gastric cancer after gastrectomy.Methods From January 2001 to December 2004, the clinic pathological data of 141 patients with recurrence and metastasis after radical gastrectomy in Tianjin Medical University Cancer Institute and Hospital were analyzed retrospectively.The possible clinic pathological factors which may affect tumor recurrence were analyzed.Results After the surgery, the 1, 2, 3 and 5-year cumulative recurrence rates were 58.2%(82/141) 、80.1%(113/141)、89.4%(126/141) 、97.9 % (138/141)respectively.The results of multivariate analysis indicated that the tumor size,invasive depth, lymph node metastasis were independent factors which affected recurrence and metastasis after radical gastrectomy (P = 0.017, 0.003, 0.000).Invasive depth, lymph node metastasis and tumor differentiation degree were independent factors which affected early recurrence and metastasis after radical gastrectomy (P=0.042, 0.000, 0.039).Conclusions The tumor size,invasive depth, lymph node metastasis are the independent risk factors to predict the recurrence and metastasis after radical gastrectomy.Most of the recurrences and metastasis is found within 2 years after radical gastrectomy.Invasive depth, lymph node metastasis and tumor differentiation degree are the independent factors to predict early recurrence after radical gastrectomy.

OBJECTIVE: To prepare bezafibrate osmotic pump tablets(BOPT) and optimize its formulation by central composite design-response surface methodology(CCDRSM).METHODS: The amount of polyoxyethylene(PEO) N80 which used as an adjuvant of Bezafibrate osmotic pump tablets(A),the amount of Na2CO3(B),and the coating weight increase(C) were used as 3 factors for investigation,and the cumulative release amount at 1 h and 6 h respectively,and the linear correlation coefficient(r) of the cumulative release amount versus time were taken as indexes.The formulation of BOPT was optimized by CCDRSM and the optimized formulation was verified.RESULTS: The optimized formulation obtained was as follows: A 40 mg,B 20 mg,and C 29 mg.The tablets prepared in optimized formulation demonstrated good release behavior,with the absolute value of deviation of each index being less than 5%.CONCLUSION: The CCDRSM can be applied to optimize the formulation of BOPT and the established model is of satisfactory predictive value.