【Objective】To improve the adaptation of Plat-Ⅱceramic crown.【Method】The Plat-Ⅱcastable ceramic crowns were made by three methods,namely routine method,die spacer technique,and the model investing method.24 crowns were made by these three methods individually and adhered to the corresponding model die with zinc phosphate to measure the adhesive thickness and compare their adaptation.【Result】The average adhesive thickness at different parts of crown of these three groups were 52 μm、42 μm、30 μm and the margins discrepence were 63 μm、59 μm、42 μm,respectively.There is statistically difference in both the adhesive thickness and the margin discrepence with these three methods (P<0.01).【Conclusion】The crowns made from the die spacer technique and the model investing method could improve the adaptation significantly.

Abstract: Objective　In order to understand the radon exposure level of homes in Chongqing, this survey was carried out on the indoor radon concentration in 38 districts and counties of Chongqing. Methods　According to the population ratio of every 100 000 people, one monitoring site was arranged, and the number of parallel samples was 10% of the distribution sites. The monitoring sites covered 38 districts and counties in Chongqing. A total of 1 019 residential monitoring sites in 38 districts and counties in Chongqing were measured with radon accumulation detectors from July 2020 to June 2021. Results　The five districts/counties in Chongqing having the highest average concentration of residential radon in the year were Xiushan County 78.8 Bq/m3, Qianjiang District 78.0 Bq/m3, Yubei District 73.9 Bq/m3, Youyang County 71.4 Bq/m3 and Shapingba District 69.8 Bq/m3. The five districts/counties with the lowest mean concentration of indoor radon were 37.6 Bq/m3 in Zhongxian County, 36.4 Bq/m3 in Changshou District, 33.7 Bq/m3 in Kaizhou District, 33.2 Bq/m3 in Liangping District and 27.3 Bq/m3 in Wushan County. The concentration levels of radon in four seasons were 46.0 Bq/m3, 53.4 Bq/m3, 45.1 Bq/m3 and 59.5 Bq/m3, respectively. The concentration of radon was higher in Summer and Winter, and lower in Spring and Autumn, and the difference of concentration among four seasons was statistically significant (P<0.001). The radon concentration of newly built buildings after 2017 was relatively high, up to 61.8 Bq /m3, but there was no statistical significance in radon concentration in different building ages (P>0.05). The concentration of radon in rooms of buildings with less than 10 floors was higher, up to 63.2 Bq /m3, and there were significant differences in radon concentration among rooms of different floors (P<0.05). The average annual radon concentration in houses in Chongqing was about (51.6±19.5) Bq/m3, and the average annual effective dose of inhaling radon and its progeny by house-related people was about (1.38±0.52) mSv. Conclusion　The average annual radon concentration level of houses in Chongqing is within the standard limit value recommended by China, but the prevention and control of radon should be strengthened.

Objective To explore the feasibility of measurement uncertainty in complete blood count using internal quality con-trol(IQC) data associated with Sysmex Network Communication System(SNCS) comparative data .Methods Complete blood count assay including white blood cell(WBC) count ,red blood cell(RBC) count ,hemoglobin(Hb) determination ,hematocrit(HCT) values and platelet(PLT) count were involved to evaluate measurement uncertainty according to the instruction of CNAS-TRL-001 .Meas-urement uncertainty evaluation was established by internal measurement reproducibility using IQC data ,and standard measurement uncertainty by bias using proficiency testing(PT) data and SNCS data ,followed by relative combined standard measurement uncer-tainty and relative expanded measurement uncertainty was calculated .Meanwhile ,the measurement uncertainty was compared by u-sing PT data and SNAS comparative data .Results Relative expanded measurement uncertainty of the above mentioned index by u-sing IQC data associated with PT data was the following :WBC(10 .02% ,7 .24% ,7 .04% ,from level 1 to level 3 respectively) ,RBC (2 .40% ,1 .72% ,1 .92% ,from level 1 to level 3 respectively) ,Hb(3 .54% ,2 .56% ,2 .50% ,from level 1 to level 3 respectively) , HCT(4 .12% ,3 .18% ,2 .86% ,from level 1 to level 3 respectively) ,PLT(15 .36% ,8 .86% ,7 .94% ,from level 1 to level 3 respec-tively) .Relative expanded measurement uncertainty of the above mentioned index by using IQC data associated with SNCS compar-ative data was the following :WBC(11 .66% ,7 .34% ,6 .40% ,from level 1 to level 3 respectively) ,RBC(2 .26% ,1 .60% ,1 .64%from level 1 to level 3 respectively) ,Hb(3 .36% ,2 .36% ,2 .10% ,from level 1 to level 3 respectively) ,HCT (3 .36% ,3 .04% , 3 .18% ,from level 1 to level 3 respectively) ,PLT (13 .34% ,8 .36% ,7 .14% ,from level 1 to level 3 respectively) .Conclusion Measurement uncertainty in complete blood cell could be estimated by using IQC data associated with SNCS comparative data , which is in accord with the instrument of target measurement uncertainty .

OBJECTIVE　To study the bioequivalence of methylprednisolone (MP) tablets in healthy volunteers.METHOD　A rapid and sensitive RP-HPLC assay was modified for the determination of the drug levels in plasma. In a randomized two-way crossover design, 40 mg single dose po domestic (B) and imported (A, MedrolTM) MP tablets, respectively, were given to 18 male healthy volunteers. The parameters were estimated by non-compartment model with a statistic analysis of ANOVA and two one-side t-test.RESULTS　The tmax,cmax,t1/2 and AUC0～∞ of tablet-B and-A were (1.9±0.5) h and (2.1±0.5) h, (597.6±119.8 ) ng*mL-1 and (572.6±121.7) ng*mL-1,(2.2±0.4) h and (2.3±0.4) h,(2528.4±558.8) h*ng*mL-1 and (2571.2±647.4) h*ng*mL-1,respectively.The mean relative bioavailability of the tablet-B vs A was 99.62%. There was no significant difference between the two products.CONCLUSION　The results suggested that these two products were bioequivalent.

Advances in mechanism and application of the heating effect in breeding of microorganism are reviewed in this paper. Heat produces mutagenesis effect and screening effect. Heating mutagenesis effect is occurred through the substitution of G-C base pair induced by heat, and heating screening effect produces higher forward mutation rate induced by other mutagens.

Background and purpose:Insulin-like growth factor-1 (IGF-1) is a peptide that participates in many biological processes by stimulating the downstream signaling pathways through their interaction with IGF-1 re-ceptor (IGF-1R) and insulin receptor (IR). Bone morphogenetic proteins (BMPs) are a group of functional proteins which participate in the biological processes of proliferation and migration in many kinds of cancers and have become a hot area of cancer research. The study aimed to investigate the effects of silencingIGF-1R gene on the expression level ofBMP2 gene, and the cell proliferation and apoptosis of SMMC7721 cells.Methods:The RNAi plasmid targetingIGF-1R gene was constructed and transfected into SMMC7721 cells. Then the inhibition effect on the expression level of IGF-1R and BMP2 gene was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The SMMC7721 growth curve and cell apoptosis were detected by MTT assay and flow cytometry after they were transfected with RNAi plasmid.Results:The RNAi plasmid targetingIGF-1R gene was constructed successfully. The inhibition efficiencies at mRNA expression levels were 68.9% and 80.7% (IGF-1R gene), 79.5% and 83.3% (BMP2 gene), respectively, after transfection with IGF-1R-siRNA-1 and IGF-1R-siRNA-2 plasmid (P<0.05). The inhibition efficiencies at protein levels were 46.1% and 62.1% (IGF-1R gene,P<0.05), 42.5% and 60.9% (BMP2 gene,P<0.05), respectively. The results of MTT growth curve showed that the proliferation rate in the transfected SMMC7721 cells was significantly slower than that in the control group (P<0.05). The proportion of apoptotic cells in transfected groups was significantly higher than that in the control group (P<0.05).Conclusion:SilencingIGF-1R gene can downregulate the expression ofBMP2 gene at different levels that results in inhibition of cell proliferation and promotion of apoptosis in SMMC7721 cells.

Objective To investigate the expression of Toll-like receptors 2 (TLR2) mRNA,p38 mitogen activated protein kinase(p38 MAPK) mRNA and cytokine in peripheral blood of children with measles and to study the effect and possible mechanism for TLR2-p38 MAPK signal pathway defects on immune suppression in the children with measles during acute phase.Methods Thirty children with measles hospitalized in the department of infectious diseases from June 2012 to July 2013 were enrolled into the measles group,and 30 healthy children were chosen as the healthy control group.The mRNA expressions of TLR and p38 MAPK in peripheral blood mononuclear cells (PBMC) were detected by reverse transcription-polymerase chain reaction (RT-PCR).The protein levels of interferon-γ (IFN-γ),tumor necrosis factor-β (TNF-β),interleukin (IL)-12,IL-6 and IL-10 in plasma were measured by using enzyme linked immunosorbent assay (ELISA),and flow cytometry (FCM)was applied to detect the percentage of lymphocyte subpopulation.The serum IgG,IgA and IgM levels were detected by velocity scatter turbidimetry.Results (1) The expressions of TLR2 mRNA and p38 MAPK mRNA in the measles group were both significantly lower than those in the healthy control group (all P ＜ 0.05).(2) Compared with the healthy control group,the protein levels of IFN-γ,TNF-β and IL-12 in the plasma of the measles group decreased significantly (all P ＜ 0.05),and the levels of IL-6 and IL-10 increased significantly(all P ＜ 0.05).(3)Compared with the healthy control group,the percentage of CD3 +,CD4 +,CD4 +/CD8 + ratio and the level of IgG and IgA in the measles group decreased significantly(all P ＜ 0.05),and the percentage of CD19 + increased significantly(P ＜ 0.05),but there was no any significant change in the percentage of CD8 + and the level of IgM (all P ＞ 0.05).Conclusions The mRNA expressions of TLR2 and p38 MAPK are low in PBMC in the measles children during acute phase.There are different degrees of suppression of cell immunity,humoral immune and cytokines disorder in children with measles.Defects of TLR2-p38 MAPK signal pathway may cause the formation of measles immune suppression.

OBJECTIVEThe clinical diagnosis and treatment of ischemia mitral regurgitation (IMR) remained difficult because of its unclear mechanisms. This paper reviews studies on the mechanisms of IMR during the last 20 years, and discusses the relevance of the various mechanisms.

DATA SOURCESData used in this review were mainly from CNKI and Pubmed in English. The search terms were "ischemia mitral regurgitation mechanism", "myocardial infarction" AND "mitral regurgitation".

STUDY SELECTIONArticles were selected if they involved mechanisms of IMR.

RESULTSIMR is one of the common complications of coronary artery disease. But currently, the clinical diagnosis and treatment of IMR remained difficult because of its unclear mechanisms.

CONCLUSIONSFor now, dominating theory of ischemic mitral regurgitation mechanisms are left ventricular remodeling, imbalance of leaflet tethering and the closing force, left ventricular dysfunction, changes in spatial structure of the annulus and the dyssynchrony of the left ventricular electromechanical activity.

Animals ; Humans ; Mitral Valve Insufficiency ; etiology ; Myocardial Ischemia ; complications ; Papillary Muscles ; physiology ; Systole ; Ventricular Dysfunction, Left ; complications ; Ventricular Remodeling

An S-naproxen（S-NAP）molecularly imprinted monolithic stationary phase（MIMSP）with specific recognition for S-NAP and naproxen（NAP）was prepared by in situ technique,utilizing 4-vinylpridine（4-VP）as a function monomer,ethylene glycol dimethacrylate（EDMA）as a cross-linking agent,and low-polar solvents（toluene and dodecanol）as porogenic solvents.The selectivity of the polymers for S-NAP and NAP was evaluated by high performance liquid chromatography（HPLC）.The binding characteristics were tested by Scatchard analysis.Racemic NAP could be specifically separated to some extent.At the same time,NAP could be separated from ibuprofen under optimized conditions.Scatchard analysis showed that two classes of binding sites existed in the S-NAP-imprinted polymers,with their dissociation constants estimated to be 1.045 and 5.496 μM,respectively.The results demonstrate that S-NAP and NAP can be recognized specifically on the obtained MIMSP.

An S-naproxen (S-NAP) molecularly imprinted monolithic stationary phase (MIMSP) with specific recognition for S-NAP and naproxen (NAP) was prepared by in situ technique,utilizing 4-vinylpridine (4-VP) as a function monomer,ethylene glycol dimethacrylate (EDMA) as a cross-linking agent,and low-polar solvents (toluene and dodecanol) as porogenic solvents.The selectivity of the polymers for S-NAP and NAP was evaluated by high performance liquid chromatography (HPLC).The binding characteristics were tested by Scatchard analysis.Racemic NAP could be specifically separated to some extent.At the same time,NAP could be separated from ibuprofen under optimized conditions.Scatchard analysis showed that two classes of binding sites existed in the S-NAP-imprinted polymers,with their dissociation constants estimated to be 1.045 and 5.496 μM,respectively.The results demonstrate that S-NAP and NAP can be recognized specifically on the obtained MIMSP.