ABSTRACT
BACKGROUND:Due to limitations of the physicochemical properties of soft denture liner material itself, whisker has been added in the soft lining material in recent years, so as to enhance its mechanical properties. OBJECTIVE:To investigate the effect of different additive amount of anhydrous calcium sulfate whisker on the mechanical function of self-curing soft denture liner. METHODS: There were six groups in this experiment. Anhydrous calcium sulfate whisker at the mass fraction of 0 (control), 1%, 2%, 3%, 4%, 5% was respectively added into self-curing soft liner materials, 10 test specimens in each group, a total of 60 test specimens. The shear bond strength, Shore hardness and tensile strength were detected. RESULTS AND CONCLUSION: With the increasing amount of the anhydrous calcium sulfate whisker, the Shore hardness of the soft lining material was increased continuously, and the tensile strength was increased firstly and then reduced. When 3% anhydrous calcium sulfate whisker was added, the bond strength and tensile strength of soft lining material reached the peak. Taken together, the mechanical properties of the soft lining materials became perfect when 3% anhydrous calcium sulfate whisker was added. These results demonstrate that anhydrous calcium sulfate whisker may affect the mechanical properties of self-curing soft liner.
ABSTRACT
Objective:To research on the immune recognition mechanism of synthetic pyrethroids and generic specific antibody.Methods:We studied on quantitative structure-activity relationship ( QSAR ) of synthetic pyrethroids and their analogs as well as antibody activity ( IC50:fifty percent inhibition concentration ) using stepwise multiple linear regression method.Based on calculating structure descriptors of synthetic pyrethroids and their analogs , two-demensional QSAR ( 2D-QSAR ) model was established.The main factors affecting antibody activity were screened using 2D-QSAR,and predictive ability of QSAR models were evaluated by the method of leave-one-out( LOO) cross-validation.Meanwhile, the structure parameters of synthetic pyrethroid fragments were calculated and then analyzed using partial least squares ( PLS) assay.And then hologram QSAR ( H-QSAR) model was constructed on molecular substructure and antibody activity.The fragments contribution to antibody activity were illustrated by encoding different colors.Results:Decision coefficent (R2) of 2D-QSAR model and HQSAR model were 0.920 and 0.917 individually,cross-validation coefficient ( Q2 ) of two QSAR models were 0.875 and 0.660 respectively ,which showed two models had good predictive abil-ity.The result from 2D-QSAR model was also obtained that smaller was hydrophobicity of pyrethroids , easier was recognized by antibody.In addition,the optimum HQSAR model was constructed after we tried many combinations of these parameters .The fragment size in optimum HQSAR model was between 4 to 10,a hologram length was 61,optimum principle component was 4,and the fragment type of B/C/Ch was selected.However ,the fingerprint encoded results of synthetic pyrethroids weren′t consistent completely with exper-imental IC50 values.Conclusion:Hydrophobicity of synthetic pyrethroids is the largest correlation factors in antibody recognization .
ABSTRACT
BACKGROUND:Microleakage between restoration, tooth structure and bonding agent can cause the entry of bacteria and liquid in the mouth into the gap, thereby damaging the bonding interface between the restoration and tooth tissues, and leading to bond failure. Microleakage detection can directly show whether the closure of the root canal of post and core system is good or bad. The severity of microleakage directly affects the restorative effects of post and core. OBJECTIVE: To evaluate the effects of different root canal cleaning methods on the microleakage between the fiber post and root canal dentin. METHODS: Thirty fresh non-caries premolar posts with free root canalin vitro were randomly divided into five groups, and the root canal wal was respectively washed with saline, 5.25% sodium hypochlorite solution+17% ethylenediamine tetra-acetic acid (EDTA)+saline, 3% hydrogen peroxide solution+5.25% sodium hypochlorite+ saline, 3% hydrogen peroxide solution+2% chlorhexidine solution+saline, and 2% chlorhexidine solution+17% EDTA+saline in different groups. Super-bond C&B adhesive agent was used for bonding fiber post, and the microleakage of each sample was observed under stereomicroscope. RESULTS AND CONCLUSION: The severity of microleakage in the al groups was ranged as folows: saline group > 3% hydrogen peroxide solution+5.25% sodium hypochlorite+saline group > 5.25% sodium hypochlorite solution+17% EDTA+saline and 3% hydrogen peroxide solution+2% chlorhexidine solution+saline groups > 2% chlorhexidine solution+17% EDTA+saline group.
ABSTRACT
Objective:AFM1-BSA and AFM1-OVA were synthesized and then identified in this experiment.Methods: Using oximation method ,AFM1 was transformed to oxime compounds while the reaction process was monitored via TLC method aiming to identify the compounds.Coupled with carrier protein BSA and OVA respectively , we obtained AFM1-BSA and AFM1-OVA, then identified synthetic antigen via UV spectrophotometry and SDS-PAGE.Antigens were injected into experimental animals , finally obtaining the murine multi-antiserum.Eventually , the multi-antiserums were detected via indirect inhibition ELISA method to judge whether the antigens were effectively or not.Results:After oximation reaction ,the migration distance of oxime compounds in the thin layer plate was shorter.The maximum absorption peak of AFM1-BSA occurred in 274 nm,and was inconsistent with both UV absorption peaks of BSA and AFM 1.The electrophoretic velocity of AFM 1-BSA was less than that of BSA.All the titers of three immunized mice were 1×10-4 approximately;the multi-antiserum from No.3 sample had the best sensitivity ,its IC50 was 359.9 ng/ml.Conclusion:In this study,we obtained AFM1 artificial antigen and murine multi-antiserum of high sensitivity.
ABSTRACT
BACKGROUND:At present, there are stil differences in the studies of total-etch, self-etch and self-bonding resin cement effect on the coronal microleakage and bonding strength of fiber posts. OBJECTIVE:To evaluate the coronal microleakage and the bonding strength of fiber posts treated with three kinds of resin cements. METHODS:Total y 32 upper incisors were randomly divided into five groups, including three experimental groups and two control groups. After the root canal preparation, three kinds of resin cements (EMBRACE WetBond, LuxaCore, Medental Multi-cure) were used to fiber posts with the bond diameter of 1.4 mm. Stereomicroscope was used to observe the microleakage. Then, the specimens were cut into 2 mm wafer along the axis of tooth, and universal testing machine for push-out test was used to observe the failure mode. In the positive control group, no root canal preparation was done, the root was coated with nail polish, and the crown was directly exposed to the dye. In the negative control group, no root canal preparation was done, the root canal orifice was covered with the resin, the tooth was overal coated with nail polish and then embedded 1 mm below the section. RESULTS AND CONCLUSION:The microleakage was observed in al the three resin cements, Medental Multi-cure showed the least microleakage and LuxaCore showed the largest microleakage, and there was significantly different among the three kinds of resin cements (P<0.05). The bonding strength of three cements had significant differences (P<0.05), and ranked from high to low:Mdental Multi-cure, LuxaCore, and EMBRACE WetBond. The main fracture modes were binder/fiber post fracture and mixed failure. The results suggest that the total-etch resin cement binds tightly with the dentin, and owns a superiority in the microleakage and bonding property as compared with the self-etch resin cements and self-bonding resin cements.
ABSTRACT
Objective:To research on protective immunity of omph DNA vaccine against avian Pasteurella multocida in mice.Methods: The omph gene fragment amplified by PCR from avian Pasteurella multocida was cloned into pMD18-T.Subsequently it was subcloned into the eukaryotic expression vector pcDNA3.1(+),and the recombinant plasmid pOMPH was obtained.Then the recombinant plasmid was trans fected into SP2/O cells in vitro.The transcription and expression of target gene were analyzed by RT-PCR,Westem blot analysis and indirect immunofluorescence.Three groups of BALB/c mice(n=16) named pOMPH,pCDNA3.1(+) and PBS were intramuscularly vaccinated with the recombinant plasmid,control vector and PBS respectively.The serum antibodies were detected by indirect ELISA.The spleen lymphocyte proliferation (SLP) and secreted IFN-γof spleen were tested by MTT.The mice were challenged with virulent of avian Pasteurella multocida on week 2 post the third immunization,the protection rate were counted.Results: RT-PCR,Western blot analysis and indirect immunofluorescence showed that the omph gene could be,transfected into SP2/0 cells in vitro and expressed the target protein.Indirect ELISA showed that the levels of antibodies in pOMPH group were most significantly higher than in the other groups(P＜0.01).Spleen lymphocyte proliferation by MTT assay indicated that the SI value induced with avian Pasteurella multocida Omps in pOMPH group was higher than those in pCDNA3.1 (+) and PBS groups (P＜0.05).The IFN-γexperiments(Double-antibodies-sandwich-ELISA)showed that the levels of IFN-γ induced with Omps in the group of pOMPH was mostly higher than in the other control groups apperent(P＜0.01 ).The protection rate of pOMPH(70%) was better than in the other groups.Conclusion: The omph DNA vaccine against avian Pasteurella multocida had been constructed successfully.The DNA vaccine could enhance the immunity level and the protective effect of the vaccinated mice.Present study may be useful for the development of avian Pasteurella multocida vaccine.
ABSTRACT
The clinical practice is a very important link for medical students to relate theory with practice and to be trained comprehensively.Stomatology is an applied science,so clinical practice is more outstanding and important during the stomatological education.This thesis discusses how to improve stomatological students' comprehensive skill in the clinical practice.
ABSTRACT
Objective:To research on protective immunity of omph DNA vaccine against avian Pasteurella multocida in mice.Methods:The omph gene fragment amplified by PCR from avian Pasteurella multocida was cloned into pMD18-T.Subsequently it was subcloned into the eukaryotic expression vector pcDNA3.1(+),and the recombinant plasmid pOMPH was obtained.Then the recombinant plasmid was transfected into SP2/0 cells in vitro.The transcription and expression of target gene were analyzed by RT-PCR,Western blot analysis and indirect immunofluorescence.Three groups of BALB/c mice(n=16) named pOMPH,pCDNA3.1(+) and PBS were intramuscularly vaccinated with the recombinant plasmid,control vector and PBS respectively.The serum antibodies were detected by indirect ELISA.The spleen lymphocyte proliferation (SLP) and secreted IFN-? of spleen were tested by MTT.The mice were challenged with virulent of avian Pasteurella multocida on week 2 post the third immunization,the protection rate were counted.Results:RT-PCR,Western blot analysis and indirect immunofluorescence showed that the omph gene could be transfected into SP2/0 cells in vitro and expressed the target protein.Indirect ELISA showed that the levels of antibodies in pOMPH group were most significantly higher than in the other groups(P