Objective:To study the residual stress distribution through the thickness of bilayered dental ceramic subjected to thermal stress, in order to improve the restoration. Methods: The finite element model of bilayered dental ceramic was set up based on International Organization for Standardization(ISO) 96936:1999. The residual stresses were calculated in viscoelastic and elastic phases during cooling of dental ceramic to analyze the residual stress distribution. Results: The deformation of core was greater than the veneer ceramics during the cooling period of dental ceramic. The residual stress increased with the decreasing of the temperature approaching the interface of core and veneer ceramics. But it decreased with the increasing of the thickness of veneer ceramics.Conclusion: Thermal compatibility of core and veneer ceramics is very important to the residual stress distribution in the bilayered dental ceramic, which may benefit to All-ceramic restorations. The viscoelastic behavior of ceramic should be taken into account in the thermal compatibility.

Objectives To investigate antimicrobial resistance and beta-lactamase production of Moraxella catarrhalis isolates from respiratory tract in children and to understand the characteristics of BRO beta-lactamase gene. Methods From June 2011 to Sep-tember 2012, 401 Moraxella catarrhalis isolates were obtained from respiratory tract in children. Minimum inhibitory concentrations (MIC) of commonly-used antibiotics were determined by microbroth dilution assay, and beta-lactamase production was detected by Nitroceifn disk test. PCR combining restriction endonuclease analysis was employed to do the BRO genotyping. Results 96.5%iso-lates were beta-lactamase positive (387/401), MIC (MIC50/MIC90) values and resistant rates of beta-lactamase producing isolates were higher than those of non beta-lactamase producing isolates for ampicillin, cefaclor and cefuroxime (P<0.05). The positive rate of BRO gene was 99.2%in beta-lactamase producing isolates (384/387), consisting of 93.0%BRO-1 isolates and 7.0%BRO-2 isolates. MIC50 and MIC90 values of BRO-1+isolates were higher than those of BRO-2+isolates for ampicillin, cefaclor, cefuroxime and azithromycin. Conclusions The beta-lactamase production rate is high in Moraxella catarrhalis isolates from respiratory tract in children. BRO-1 type was the dominant genotype of beta-lactamase producing isolates, having more inlfuence than BRO-2 type in the inlfuence on some beta-lactams and macrolides.

Objective:To investigate the surface characterization,cell adhension and proliferation of ultrafine grained titanium (UFG Ti) after different sand blasting and acid-etching(SLA).Methods:The billets of UFG Ti and commercially pure titanium Ti(CP Ti) were incised into cylindrical specimens with 7 mm in diameter and 2 mm in height.The specimens were sand blasted at the air pressure of 0.2,0.4,0.6 and 0.8 MPa respectively(n =10) and then acid-etched.The surface morphology,roughness and surface wettability of the specimens were examined.Rat embryo osteoblasts MC3T3-E1 were cultured on the speciments for 1 d,3 d and 5 d respectively,the cell morphology and cell density were observed.Results:The different hierarchical porous topographies were formed on the surface of UFG and CP Ti after modified by SLA.The sizes of blasted holes on the surface and the surface roughness of both materials increased with the increase of blast pressure,but the values of UFG Ti were lower than those of CP Ti correspondingly(P ＜ 0.05).The surface wettability of them was also changed with the blast pressure,but the values of UFG Ti was significantly smaller than those of CP Ti(P ＜ 0.05).When the blast pressure was 0.6 Mpa,the UFG Ti exhibited excellent wettability,the cell density was the highest,the morphology of MC3T3-E1 cells on UFG Ti was superior to that on CP Ti.Conclusion:UFG Ti exhibits proper surface morphology,roughness and excellent wettability,which is more appropriate for adhension and proliferation of MC3T3-E1 cells after modification by SLA at blast pressure of 0.6 Mpa.

AIM:To investigate the molecular mechanism of inhibition of miR-421 expression promoting radiosensitivity in the cervical cancer cells.METHODS:Cervical cancer lines HeLa, SiHa, C33A and CaSki were transfected with miR-421 inhibitor or negative control nucleotide using Lipofectamine 2000 kit, and the levels of miR-421 expression in the cervical cancer lines and endometrial epithelium cell line ESC were detected by real-time PCR.These cells with transfection were exposed to various doses of X-ray (0, 2, 4, 6 and 8 Gy).After 48 h, the cell viability, LDH leakage rate and apoptotic rate were measured respectively by MTT assay, ELISA and flow cytometry with Annexin V-FITC/PI staining.The protein levels of cleaved caspase-9, caspase-9, cleaved PARP, PARP, Bcl-2 and Bax were monitored by Western blot.RESULTS:Low miR-421 levels was found in the ESC cells, while high miR-421 levels were observed in the HeLa, SiHa, C33A and CaSki cells.The level of miR-421 in the cells transfected with miR-421 inhibitor was significantly lower than that in negative control group (P<0.05).The viability and LDH leakage rate of the cervical cancer cells with low miR-421 expression were notablely lower than those in negative control group, and the apoptotic rate at 72 h was remarkablely increased (P<0.05) under the same conditions.The results of Western blot indicated that, after exposure to ionizing radiation, the protein levels of cleaved caspase-9, cleaved PARP and Bcl-2 were significantly increased, while the protein level of Bax was significantly decreased in the cervical cancer cells with low miR-421 expression compared with negative control group (P<0.05).CONCLUSION:miR-421 is lowly expressed in the normal endometrial epithelial cells, but highly expressed in the cervical cancer cells.Down-regulation of miR-421 expression significantly inhibits the growth and enhances the radiosensitivity of cervical cancer cells at least partly via activating caspase-9 apoptosis pathway, thus promoting Bcl-2 and inhibiting Bax expression.

Objective:To evaluate the reliability of flexural strength and subcritical crack growth(SCG)of WL and HT zirconia ce-ramics under cyclic loading.Methods:Bar-shaped speciments of WL(n =30)and HT(n =30)were fabricated and loaded in three-point bending and cyclically fatigued.The flexural strength and the number of cycles to fracture were obtained from three-point flexural test and cyclic fatigue test respectively.Data were examined using Weibull statistics.Pairs law was used to analysize the subcritical crack growth(SCG),the behavior of which was described in terms of crack velocity as a function of maximum stress intensity factor (KImax ).Results:The Weibull module(m)of WL and HT was 10.64 and 12.04,the stress corrosion cracking susceptive indexes(n) 23.71 and 32.87,the SCG 90% and 76.7%,the KImax 49.6% and 50.9% of its maximum stress intensity factor(KIC ),respectively. Conclusion:WL and HT produce pronounced SCG.The minimum fatigue crack growth rate of HT is lower than that of WL(νHT <νWL ).

OBJECTIVETo observe the effect of heart protection on diabetic cardiomyopathy in rats by tripterysium glucosides.

METHODThe rat diabetic cardiomyopathy rats model are made by streptozotocin, then divided into tripterysium glucosides group (n=8) and model group (n=8). In addition, the control group is established (n=8). Glucosides group was orally administrated tripterysium glucosides (18 mg x kg(-1)), the control groups was orally administrated same volume NS for 3 months. Blood sugar, heart function and cardiac index were detected after 3 months. Immunohistochemical techniques were used to detect NF-kappaB and ICAM-1 expression. Ultrastructure of cardiac muscle cell were observed by electronmicroscope.

RESULTCompared with model group, cardiac index was decreased after tripterysium glucosides administration, and LVSP, LVEDP, + dp/dtmax, -dp/dtmax, were improved, and the expression of nuclear Factor-kappaB (NF-kappaB) and intercellular adhension molecule-1 (ICAM-1) was inhibited. Ultrastructure of cardiac muscle cell such as mitochondrion and cardiac muscle fibers was atttenuated.

CONCLUSIONTripterysium glucosides could protect rat diabetic cardiomyopathy rats heart. These function may be related to inflammatory reaction inhibition and immunosuppression of tripterysium glucosides.

Animals ; Blood Glucose ; metabolism ; Cardiomyopathies ; etiology ; metabolism ; pathology ; physiopathology ; Diabetes Mellitus, Experimental ; complications ; Gene Expression Regulation ; drug effects ; Glucosides ; administration & dosage ; pharmacology ; therapeutic use ; Heart ; drug effects ; Intercellular Adhesion Molecule-1 ; metabolism ; Male ; Myocardium ; ultrastructure ; NF-kappa B ; metabolism ; Rats

OBJECTIVE:To study the effects of flow components C6 and C7 in n-butyl alcohol extract from the leaves of Ces-trum Nocturnum(CN)on the proliferation and apoptosis of human gastric cancer cell SGC7901. METHODS:C6 and C7 were ob-tained by using different ratio of chloroform and methanol(1:9,1:7)to the gradient elution of CN leaves. After cultured with 0 (blank control),5,10,20,40,80 μg/ml C6 and C7 for 72 h,inhibitory effect of C6 and C7 on the proliferation of SGC7901 was determined by MTT assay. Inhibitory rate and IC50 were calculated. After SGC7901 were cultured with 10 μg/ml C6 and C7 for 72 h,colony formation assay was utilized to detect the effects of C6 and C7 on the cell colony formation,and the rate of colony for-mation was calculated. In addition,Wright/Giemsa and Hoechst33258/PI staining assay were used to observe the change of cytomor-phology. RESULTS:MTT showed that C6 and C7 had inhibitory effect on the proliferation of SGC7901 to different extent;inhibi-tory rates were 22.1%-80.0% and 19.6%-79.7%,and IC50 were 16.4,18.05 μg/ml,respectively. Compared with blank control group,colony formation rate of C6 and C7 group decreased,with statistical significance(P<0.05). The number of apoptotic cells was more in treatment group than in other groups. CONCLUSIONS:Flow components C6 and C7 in n-butyl alcohol extract from the leaves of CN can inhibit the proliferation of SGC7901 cells and induce the apoptosis of them.

0.05)in healthy volunteers.

Aim Toconstructthreeplasmidsincluding Smad3 WT,Smad3 EPSM and Smad3 3S-A stable transfection in HepG2 cell lines to investigate phospho-domains of Snad3(pSmad3C or pSmad3L),their pro-tein expression and roles in HepG2 cell proliferation, apoptosisandcellcycle.Methods Threeplasmidsin-cluding Smad3 WT (Carry the wild Smad3 gene ), Smad3 EPSM(Carry the mutated phosphorylation site in linker region of Smad3 gene)and Smad3 3S-A(Car-ry the mutated phosphorylation site in C-terminal of Smad3 gene)were respectively transfected into HepG2 cells by using a liposome transfection reagent.Verifi-cation of positive cells was done by screening with G418 via co-culture.Transfection efficiency was deter-mined by Western blot.Cell proliferation was induced by exogenous TGF-β1 in the respective stably transfect-ed HepG2 cell lines.Cell proliferation was monitored by MTT.Cell cycle and apoptosis were determined by flowcytometry(FCM).Results Therewaselevated protein expression of the respective phospho-domain sites in the stably transfected HepG2 cells for Smad3 WT(C-terminus and Linker),Smad3 EPSM(C-termi-nus)and Smad3 3S-A(Linker),which indicated suc-cessful stable transfection of HepG2 cell lines.The re-sults from MTT experiment showed that TGF-β1 could induce proliferation of HepG2 cells with or without the transfection of Smad3 WT,Smad3 EPSM and Smad3 3S-A plasmids,meanwhile transfected Smad3 EPSM plasmids could significantly inhibit proliferation of HepG2 cells induced by TGF-β1 , and transfected Smad3 3S-A plasmids accelerate proliferation of HepG2 cells induced by TGF-β1 .Cell cycle analysis showed that the G0/G1 phase of HepG2 cells with stable trans-fection of Smad3 EPSM plasmid increased compared with HepG2 cells with or without stable transfection of Smad3 WT plasmid,meanwhile the G2/M phase of HepG2 cells with stable transfection of Smad3 3 S-A plasmid increased.Compared with Smad3 WT trans-fected cells, apoptosis in Smad3 EPSM transfected cells was markedly increased,while that of Smad3 3S-Atransfectedcellsdecreased.Conclusions Thethree plasmids of Smad3 WT,Smad3 EPSM and Smad3 3S-A stably transfected HepG2 cell lines have been suc-cessively constructed.The construction of three plas-mids transfected HepG2 cell lines provides the research foundation for studying medical as well as possible reg-ulatory mechanism of pSmad3 C/pSmad3 L.

OBJECTIVEThe theory of strain energy density (SED) was combined with finite element analysis to investigate alveolar bone remodeling of the mandibular first molar with different levels of periodontal attachment under mastication loading.

METHODSThree-dimensional finite element models of the mandibular first molar with different levels of periodontal attachment were established. Based on SED theory, the user material subroutine (UMAT) (used by ABAQUS software) was developed by ourselves to simulate the remodeling process of mandibular bone. The stress distributions and bone density changes were analyzed under different mastication loading. The influence of loading magnitude on alveolar bone remodeling with different levels of periodontal attachment was investigated.

RESULTSThe results showed that the neck of buccal, lingual regions and root apex area experienced a higher stress. The stress and the density of alveolar bone increased gradually with the enhancing of the bite force at the beginning. Then the density would appear declining when the bite force exceeded the extreme load. The extreme load reduced from 420 N to 240 N with the periodontal attachment falling from normal to 1/2 of root length also. And the remodeling rate of the bone was faster as the loading increasing.

CONCLUSIONThe capability of the periodontal tissue for supporting the teeth will drop gradually as the periodontal attachment level dropping. And the decline of bone density also appeared in earlier time. The change of density is associated with mastication loading during the bone remodelling. And reducing the occlusal force properly to the molar with different attachment level is benefit for clinical treatment and prognosis of periodontal disease.

Bite Force ; Bone Density ; Bone Remodeling ; Finite Element Analysis ; Humans ; Mandible ; Mastication ; Models, Biological ; Molar ; Stress, Mechanical ; Tooth Root