No abstract available.

OBJECTIVETo make a mechanical analysis on three-dimensional finite element models of the mandibular first molar with the maximum distal occlusal (DO) structure defect after the root canal therapy and filling and crown restoration under static and impact loads and to provide a guideline for planning restoration for the clinic.

METHODSThe research adopted reverse engineering technology to build the model of three-dimensional finite element. The form of the intercuspal occlusion and cusp to cusp occlusion during the circulation of posterior teeth occlusion movement were simulated. Half-sine pulse/impact was chosen for the impact dynamic. The impact ratio was indicated to the stress change between impact loads and static loads.

RESULTSUnder the two kinds of loads, the maximum Mohr stress values of the metal crowns were shown in all models. The restoration effects between the two kinds of models were compared, the maximum Mohr stress value of the crown metal and dentin was not obviously difference. The maximum Mohr stress values of dentin were all obviously smaller than the stretch limit strength of dentin. The impact ratio closed to 1.

CONCLUSIONThe impact loads accorded with the oral actual situation more than the static loads, but the suitable analysis of the static loads could be accepted. The restoration of metal crown is necessary. The effects between the amalgam filling and full crown restoration and composite resin filling and full crown restoration is not difference obviously.

Composite Resins ; Crowns ; Dentin ; Finite Element Analysis ; Humans ; Molar

Antibodies, Viral ; blood ; China ; epidemiology ; Female ; Humans ; Immunoglobulin G ; blood ; Male ; SARS Virus ; immunology ; isolation & purification ; Seroepidemiologic Studies ; Severe Acute Respiratory Syndrome ; epidemiology ; virology

Objective To investigate the mobidity and risk factors for primary hypothyroidism (HT) in nasopharyngeal cancer (NPC) patients treated with intensity-modulated radiotherapy (IMRT). Methods 113 NPC patients with complete clinical information who received IMRT from 2008-2010 were retrospectively analyzed. Thyroid function assessments before and after IMRT were periodically monitored. Various clinical and dosimetric parameters were obtained including Dmin ,Dmax ,Dmean ,V30 ,V35 ,V40 ,V45 ,V50 , V55 ,V60 , V65 , V70 ( thyroid gland ) , PDmin , PDmax , PDmean ( pituitary gland ) . Univariate and multivariate logistic regression analyses were performed to identify predictors of HT. Results After a median follow-up period of 62 months,41 patients ( 363%) had clinical HT,and 28 patients ( 248%) developed subclinical HT. Univariate analysis revealed that younger age, mean dose to the thyroid gland, V40 , V45 , V50 , V55 , V60 were correlated with developing HT ( all P<005 ) . On multivariate analysis including patient, tumor, and treatment variables,younger age ( P=0002) and V50 ( P=0002) remained statistically significant. We found that the cutoff value of V50(50%) may be an valuable evaluation marker of HT.Combined with age to predict the HT,the area under ROC curve is 0728.The endpoint event rate of the patients whose level of V50 is above 50% and age level below 45 years were 793%,whlie the date in patients whose level of V50 is below 50% and age level above 45 years was 318%. Conclusions Thyroid V50 above 50% is predictive of primary HT after IMRT for NPC patient, Our results suggested that restricting V50<50% during IMRT planning may facilitate the reduction in incidence of HT for the younger patients.

The CRISPR/Cas9 gene editing technology directs Cas9 protein to recognize, bind and cleave the target site specifically by using artificial single-guide RNA (sgRNA), through non-homologous end joining or homologous end-recombinant repair mechanisms of cells, which can be engineered to knockout or knock-in of genomes. RIG-I is a pattern recognition receptor that recognizes the 5'-triphosphate-containing RNA in the cytoplasm and activates IRF3/7 and NF-κB by interacting with the downstream signaling molecule MAVS, thus initiating the expression of type I interferons and inflammatory factors. Previous studies found that influenza B virus (IBV) can up-regulate the expression of RIG-I. In the present study, to explore whether RIG-I is the major receptor for IBV to active the antiviral innate immune response and its effect on IBV replication, RIG-I gene in 293T cells was knocked out by CRISPR-Cas9 system, and a stable RIG-I knockout 293T (RIG-I(-/-) 293T) cell line was screened by puromycin pressure. The results of Western blotting showed that RIG-I was not expressed in this cell line after IBV or Sendai virus (SeV) infection, indicating that the RIG-I(-/-) 293T cell line was successfully constructed. The transcription levels of interferons, inflammatory factors and interferon-stimulated genes in RIG-I(-/-) 293T cells which were infected by IBV decreased significantly compared with those in wild-type 293T cells. Moreover, the phosphorylation of p65 and IRF3 were not detected in IBV or SeV infected RIG-I(-/-) 293T cells. It is indicated that the expression of cytokines mainly depends on the RIG-I-mediated signaling pathway at the early stage of IBV infection. Furthermore, the multi-step growth curves of IBV in the wild type and RIG-I(-/-) 293T cells showed that RIG-I inhibited the replication of IBV. Collectively, the RIG-I knockout 293T cell line was successfully constructed. We found that RIG-I is the main receptor for IBV to active the antiviral innate immune response and is critical for inhibiting IBV replication, which lays the foundation for further study of IBV infection mechanism.