Systematic chemical characterization of Xiexin decoctions using high performance liquid chromatography coupled with electrospray ionization mass spectrometry / 中国天然药物

Xiexin decoctions (XXDs) display beneficial anti-inflammatory and anti-diabetic effects, which raises interests on this group of formulae for broad clinical applications. However, there was no report about systematic analysis of XXDs to elucidate the constitution of chemical components, which hampers further investigations on the therapeutic values of XXDs. In this work, crude herbs were extracted and prepared to obtain the XXDs for systemic analysis on their chemical compositions, according to the information described in the ancient Zhang Zhongjing's herbal formulae. LC-MS analysis of five XXDs was carried out to facilitate recognition of the source herbs for compounds in the mixture. A total number of 93 compounds were identified through our methods and their chemical classes encompassed five major groups, including protoberberine alkaloids, flavonoids, stilbenes, anthraquinones and saponins. Our current work provided important information about material basis for pharmacological studies on XXDs and would help shed light on relationships between chemical compositions and therapeutic effects.

Reliability and validity of the Chinese version of parenting sense of competence scale in mothers of preschool children / 北京大学学报(医学版)

OBJECTIVE@#To test the reliability and validity of the Chinese version of parenting sense of competence scale (PSOC) in Chinese mothers of preschool children, and to explore the perception of preschool children's mothers on their own parenting skills and their comfort of being a parent in Yanqing District of Beijing.@*METHODS@#A cross-sectional survey was conducted using a convenience sample in 1 384 preschool children's mothers in Yanqing District of Beijing. SPSS 21.0 and Mplus 7.4 software were used for statistical analysis to test the structural validity, criterion related validity, internal consistency and split half reliability of the scale, and to analyze the score of the scale and its influencing factors.@*RESULTS@#The PSOC had good reliability and validity. Exploratory factor analysis showed that each item of the PSOC had more than 0.4 factor loading in efficacy factor or satisfaction factor, and there was no double load phenomenon. Confirmatory factor analysis showed that the factor loadings ranged from 0.212 to 0.843 in efficacy factor and satisfaction factor, respectively. The goodness of fit test showed that all the fitting indexes were within the acceptable range, and the correlation between the effectiveness subscale and the satisfaction subscale was high. The Cronbach's α coefficient of the whole scale, the efficacy subscale and the satisfaction subscale were 0.872, 0.802, and 0.874, respectively. The Spearman-Brown coefficient of PSOC was 0.851. The average score of the whole scale, the efficacy subscale, and the satisfaction subscale were 72.33±11.31, 35.54±5.91, and 36.79±7.11, respectively, and the score of parenting competence in Chinese mothers of preschool children was influenced by the mother's educational level and the annual income of her family.@*CONCLUSION@#The PSOC has satisfactory reliability and validity in Chinese mothers of preschool children. It can be used as an evaluation instrument for measuring the parenting competency, self perceived efficacy and satisfaction in the mainland Chinese mothers of preschool children. The competency of preschool children's mothers in Yanqing District of Beijing is very good, which may be related to the higher education level of the mothers and the higher annual income of their families in this study.

Effect of Dahuang Mudan Tang in Triggering Receptor Expressed on Myeloid Cells-1 in Intestinal Tract in Rats with Septic Acute Intestinal Dysfunction / 中国实验方剂学杂志

Objective:To investigate whether the therapeutic effect of Dahuang Mudan Tang on septic acute intestinal dysfunction in sepsis ratsis related to the regulation of expression of triggering receptor expressed on myeloid cells-1(TREM-1). Method:Totally 100 male SD rats were injected intraperitoneally with lipopolysaccharide (LPS) at a dose of 4.5 mg·kg-1 to build sepsis model. The sepsis model rats were randomly divided into five groups:model group, glutamine group (3.75 g·kg-1),low,medium, high-dose Dahuang Mudan Tang group(7.5,15,30 g·kg-1),and another 10 normal rats were selected as normal group. Seven days later,2 mL suspension (100 mg lactulose and 50 mg mannitol) was orally administrated by gavage, and 24 h urinewas collected. The ratio of lactulose to mannitol in urine (L/M) was detected by HPLC with pulsed electrochemical detection (HPLC-PED).Serum citrulline concentrationsin blood and ileum were determined by HPLC.Enzyme linked immunesorbent assay (ELISA) was used to detect the concentrations of triggering receptor expressed on myeloid cells-1(TREM-1),tumor necrosis factor-α(TNF-α),intestinal fatty acid binding protein(iFABP) and D-lactic acid.Real-time PCR was used to detect the mRNA expressions of TREM-1,Toll-like receptors2(TLR2),Toll-like receptors 4(TLR4),myeloid cell differentiation protein(MyD88),nuclear transcription factor-κB(NF-κB).Electron microscopy was used to observe the pathological changes of intestinal mucosa injury. Result:Compared with normal group, the serum concentrations of TREM-1,TNF-α,iFABP, D-lactate; the ratio of lactulose to mannitol in urine (L/M)and the expressions of TREM-1,TLR2,TLR4,MyD88,NF-κB mRNA in model group were increased obviously(PPPPPκB mRNA,and the serum concentrations of TREM-1 and TNF-α in all medication administration groups were decreased obviously(PD-lactate, L/M, the Chiu scorein glutamine group, medium-dose Dahuang Mudan Tang group and high-dose Dahuang Mudan Tang group were decreased obviously(PPPConclusion:Dahuang Mudan Tang can effectively treat SAID in rats, and its mechanism may be realized by regulating the expression of TREM-1 and relieving intestinal inflammation of intestinal tract.

Roles of transforming growth factor - β1 and heat shock protein 47 in progression of Schistosoma japonicum-induced hepatic fibrosis / 中国血吸虫病防治杂志

Objective To investigate the dynamic expression of transforming growth factor-β1 (TGF-β1) and heat shock protein 47 (HSP47) and explore their roles in the progression of hepatic fibrosis induced by Schistosoma japonicum infection. Methods Fifty female mice of the ICR strain were randomly divided into the infection group and the normal control group, of 25 mice in each group. Each mouse in the infection group was infected with 20 ± 1 cercariae of S. japonicum via the abdominal skin, while uninfected animals served as normal control. Five mice were sacrificed 4, 6, 8, 10 and 12 weeks post-infection and liver tissues were sampled. Serum HSP47 and TGF-β1 was determined using enzyme-linked immunosorbent assay (ELISA), and the pathological changes of liver specimens were observed with hematoxylin & eosin (HE) staining. In addition, the synthesis of alpha 1 chain of type I collagen (COL1A1) was measured using Masson staining, and the mRNA expression of TGF-β1, HSP47 and COL1A1 was determined using real-time fluorescent quantitative PCR (qPCR) assay. Results During the period of S. japonicum-induced hepatic fibrosis, the serum HSP47 and TGF-β1 levels and the mRNA expression of TGF - β1, HSP47 and COL1A1 gradually increased with the progression of hepatic fibrosis. The serum levels of HSP47 and TGF-β1 were (179.26 ± 29.87) pg/mL and (22.37 ± 5.21) ng/mL 6 weeks post-infection, respectively, which were significantly greater than those [(150.29 ± 34.91) pg/mL and (18.54 ± 7.78) ng/mL, respectively] in the normal control group (both P values < 0.05). In addition, the mRNA expression of HSP47, COL1A1 and TGF-β1 was (0.86 ± 0.04), (1.17 ± 0.06) and (0.64 ± 0.13) in mouse liver specimens, which was significantly higher than that (0.23 ± 0.03, 0.20 ± 0.02 and 0.38 ± 0.02) in the normal control group (all P values < 0.01). Conclusions The expression of TGF-β1 and HSP47 during the period of S. japonicum-induced hepatic fibrosis is consistent with the progression of the hepatic fibrosis, and exhibits the same tendency with type I collagen expression. HSP47 is a novel promising diagnosis marker and therapeutic target for S. japonicum-induced hepatic fibrosis.

Roles of transforming growth factor - β1 and heat shock protein 47 in progression of Schistosoma japonicum-induced hepatic fibrosis / 中国血吸虫病防治杂志

Objective To investigate the dynamic expression of transforming growth factor-β1 (TGF-β1) and heat shock protein 47 (HSP47) and explore their roles in the progression of hepatic fibrosis induced by Schistosoma japonicum infection. Methods Fifty female mice of the ICR strain were randomly divided into the infection group and the normal control group, of 25 mice in each group. Each mouse in the infection group was infected with 20 ± 1 cercariae of S. japonicum via the abdominal skin, while uninfected animals served as normal control. Five mice were sacrificed 4, 6, 8, 10 and 12 weeks post-infection and liver tissues were sampled. Serum HSP47 and TGF-β1 was determined using enzyme-linked immunosorbent assay (ELISA), and the pathological changes of liver specimens were observed with hematoxylin & eosin (HE) staining. In addition, the synthesis of alpha 1 chain of type I collagen (COL1A1) was measured using Masson staining, and the mRNA expression of TGF-β1, HSP47 and COL1A1 was determined using real-time fluorescent quantitative PCR (qPCR) assay. Results During the period of S. japonicum-induced hepatic fibrosis, the serum HSP47 and TGF-β1 levels and the mRNA expression of TGF - β1, HSP47 and COL1A1 gradually increased with the progression of hepatic fibrosis. The serum levels of HSP47 and TGF-β1 were (179.26 ± 29.87) pg/mL and (22.37 ± 5.21) ng/mL 6 weeks post-infection, respectively, which were significantly greater than those [(150.29 ± 34.91) pg/mL and (18.54 ± 7.78) ng/mL, respectively] in the normal control group (both P values < 0.05). In addition, the mRNA expression of HSP47, COL1A1 and TGF-β1 was (0.86 ± 0.04), (1.17 ± 0.06) and (0.64 ± 0.13) in mouse liver specimens, which was significantly higher than that (0.23 ± 0.03, 0.20 ± 0.02 and 0.38 ± 0.02) in the normal control group (all P values < 0.01). Conclusions The expression of TGF-β1 and HSP47 during the period of S. japonicum-induced hepatic fibrosis is consistent with the progression of the hepatic fibrosis, and exhibits the same tendency with type I collagen expression. HSP47 is a novel promising diagnosis marker and therapeutic target for S. japonicum-induced hepatic fibrosis.

Advances in the regulatory roles of exosomes on pathological process of schistosomiasis hepatic fibrosis / 中国血吸虫病防治杂志

Exosomes are a group of membraneous vesicles generated and released by multi-vesicular bodies or cell membranes in a variety of cell types. Acting as important messages between cells, they participate in almost every physiological and pathological process of living organisms. Exosomes contain specific proteins, mRNA, miRNAs, etc. and mediate intercellular communications, signal transductions and gene expressions effectively. Exosomes are involved in the formation of hepatic fibrosis, which is the typical liver pathological change in the progression of schistosomiasis and is caused by the liver repair and (or) regeneration involving inflammation stimulated by exosomes, activated hepatic stellate cells and other related pathways in reaction to the parasite infection. Exosomes could serve as new markers for schistosomiasis hepatic fibrosis diagnosis and potential targets for its treatment. This paper briefly reviews the latest development of studies on the regulatory roles of exosomes in schistosomiasis hepatic fibrosis, so as to provide ideas for searching new treatment targets of the disease.

Advances in the regulatory roles of exosomes on pathological process of schistosomiasis hepatic fibrosis / 中国血吸虫病防治杂志

Exosomes are a group of membraneous vesicles generated and released by multi-vesicular bodies or cell membranes in a variety of cell types. Acting as important messages between cells, they participate in almost every physiological and pathological process of living organisms. Exosomes contain specific proteins, mRNA, miRNAs, etc. and mediate intercellular communications, signal transductions and gene expressions effectively. Exosomes are involved in the formation of hepatic fibrosis, which is the typical liver pathological change in the progression of schistosomiasis and is caused by the liver repair and (or) regeneration involving inflammation stimulated by exosomes, activated hepatic stellate cells and other related pathways in reaction to the parasite infection. Exosomes could serve as new markers for schistosomiasis hepatic fibrosis diagnosis and potential targets for its treatment. This paper briefly reviews the latest development of studies on the regulatory roles of exosomes in schistosomiasis hepatic fibrosis, so as to provide ideas for searching new treatment targets of the disease.

Effect of quaternary ammonium methacrylates incorporation into a dental adhesive on the resistance of enzymatic degradation of resin-dentine interfaces / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of quaternary ammonium methacrylates incorporation into a dental adhesive on the resistance of enzymatic degradation of resin-dentine interfaces.</p><p><b>METHODS</b>Thirty caries-free extracted human third molars were randomly divided into three groups (n = 10): 2-methacryloxylethyl dodecylmethyl ammonium bromide (MAE-DB) incorporated adhesive served as the experimental group, pre-treatment with chlorhexidine (CHX) served as a positive control, Adper(TM) Single Bond 2 served as a negative control. The resin-dentin interfaces were prepared using total etch bond system. After storage in distilled water at 37 °C for 24 h, the bonded teeth were vertically sectioned into beams. Beams were respectively immersed in artificial saliva containing 2 g/L MMP-8 at 37 °C for 0 h, 24 h and 120 h (n = 30). Micro-tensile bond strength, failure modes and nanoleakage were examined.</p><p><b>RESULTS</b>There were no significantly differences of micro-tensile bond strength between groups before hydrolysis (P > 0.05). After the enzymatic hydrolysis of 24 h and 120 h, the micro-tensile bond strength of MAE-DB groups [(31.13 ± 8.77) MPa, (24.14 ± 6.64) MPa] were significantly higher than that of the negative control groups [(25.63 ± 6.90) MPa, (15.22 ± 6.57) MPa] (P < 0.05). Most of the failures were found in the base part of the hybrid layer in the negative control group, while failures occurred through the top of the hybrid layer in CHX and MAE-DB groups after the enzymatic hydrolysis.Specimens from each immediate group showed minor silver deposits in hybrid layer. After beams being enzymatic hydrolyzed for 120 h, it was shown that the silver nitrate uptake in the negative control group were significantly different from those in the CHX and MAE-DB groups (P < 0.05).</p><p><b>CONCLUSIONS</b>Dental adhesive incorporation of MAE-DB could improve the anti-degrade ability of resin-dentin interfaces.</p>

The potential effect of proanthocyanidins on the stability of resin-dentin bonds against thermal cycling / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the potential effect of proanthocyanidins (PA), a natural cross-linker, on the stability of resin-dentin bonds against thermal cycling.</p><p><b>METHODS</b>Ten percent, 15% PA-based preconditioners, and 5% glutaraldehyde were prepared for the transient pretreatment of demineralized dentin before bonding. Specimens without pretreatment were used as negative controls (n = 4 teeth for each group). Microtensile bond strength, failure mode, micromorphologies of resin-dentin interface and the collagen degradation of bonded specimens after thermal cycling were evaluated.</p><p><b>RESULTS</b>After thermal cycling, the microtensile bond strength values of resin-dentin bond in groups pretreated with 15% PA for 120 s and 60 s [(23.09 ± 3.19) and (21.88 ± 3.49) MPa] were significantly higher than that in control group [(15.47 ± 3.78) MPa] (P < 0.05). Mixed fractures were the most prevalent failure mode. Specimens with pretreatment presented compact hybrid layer, while some narrow gaps were found in hybrid layer of non-treated specimens. Collagen biodegradation rates in groups with pretreatment were significantly lower than that in control group (P < 0.05). Among them, specimens pretreated by 15% PA preconditioner for 120 s exhibited the lowest biodegradation rates [(0.316 ± 0.019) mg/g].</p><p><b>CONCLUSIONS</b>The application of natural cross-linker PA on demineralized dentin reduced the bond degradation against aging by thermal cycling, and can be helpful to create more durable bonds to dentin.</p>

The effects of p38MAPK and HBxAg on cell proliferation and apoptosis in human hepatocarcinogenesis / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the effects of host-derived p38 mitogen-activated protein kinase subunit 38 (p38MAPK) and the hepatitis B virus X antigen (HbxAg) on cell proliferation and apoptosis in human hepatocellular carcinoma (HCC), and to study the mechanism underlying hepatocarcinogenesis.</p><p><b>METHODS</b>Liver tissues were biopsied from healthy individuals and patients with chronic hepatitis B (CHB), liver cirrhosis, paratumor cirrhosis, and HCC. Immunohistochemical staining was used to detect expressions of HBxAg, p38MAPK, cell cycle G2/M phase-related factors (cdc25B, p34cdc2, cyclin B1), and cell proliferation factor ki-67.The terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling method (known as TUNEL) was used to detect apoptosis.</p><p><b>RESULTS</b>The highest rates of HBxAg were detected in CHB (65.0%) and HCC (44.4%) liver samples, and the antigen was mainly expressed in nuclei. Increasingly higher rates of p38MAPK, cdc25B, cyclin B1, and p34cdc2 expression were detected with increases in disease severity: normal liver (40.0%, 20.0%, 20.0%, and 30.0%, respectively), chronic hepatitis B (60.0%, 65.0%, 40.0%, and 50.0%, respectively), liver cirrhosis (65.0%, 75.0%, 70.0%, and 55.0%, respectively), paratumor cirrhosis (66.7%, 75.0%, 75.0%, and 63.9%, respectively), and HCC (77.8%, 80.6%, 80.6%, and 72.2%, respectively). In addition, the intracellular location of p38MAPK expression was different under different disease conditions, showing nuclear expression in CHB and liver cirrhosis samples and cytoplasmic expression in paratumor cirrhosis and HCC samples (x2 = 1.11, P more than 0.05). The proliferation index (PI) and the apoptosis index (AI) were both increased along with disease severity (normal more than CHB more than paratumor cirrhosis more than HCC) (PI: 0.0000+/-0.000, 0.0502+/-0.011, 0.0411+/-0.009, 0.0762+/-0.017; AI: 0.0351+/-0.024, 0.0607+/-0.022, 0.0562+/-0.013, 0.0716+/-0.011), with the notable exception for liver cirrhosis (PI: 0.1810+/-0.036 and AI: 0.1200+/-0.018). PI in poorly-differentiated HCC (0.2285+/-0.062) was significantly higher than in well-differentiated HCC (0.1216+/-0.032, t = 2.082, P = 0.044). AI in well-differentiated HCC (0.152+/-0.026) was significantly higher than in poorly-differentiated HCC (0.081+/-0.022, t = 2.129, P = 0.041).</p><p><b>CONCLUSIONS</b>In the process of hepatocarcinogenesis, HBxAg may cause a series of abnormal changes in cell cycle, proliferation and apoptosis by affecting the expression of p38MAPK.</p>

Role of p38MAPK in apoptosis of human paratumor cirrhosis hepatocellular cell line QSG-7701 induced by cisplatin / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the roles of p38 MAPK in apoptosis of the normal liver cell, the paratumor cirrhosis hepatocellular cell and the hepatocellular carcinoma cell.</p><p><b>METHODS</b>Three cell lines were adopted (the normal liver cell line HL-7702, the paratumor cirrhosis hepatocellular cell line QSG-7701 and the hepatocellular carcinoma cell line QGY-7703) and treated with Diamminedichloroplatin (DDP, cisplatin) and p38MAPK inhibitor SB203580. The apoptosis and cell cycles were detected by flow cytometry and electromicroscopy. The expressions of p38MAPK, CDC25B, p34cdc2 and cyclinB1 were detected by immunocytochemical staining , confocal microscopy and western blot.</p><p><b>RESULTS</b>The apoptotic rates in all three cell lines pretreated with DDP increased obviously and the rates in normal liver cells and HCC cells increased continuously even after SB203580 treatment, whereas in paratumor cirrhosis cells the rate decreased and the cell cycle stopped at S phase.</p><p><b>CONCLUSION</b>Cisplatin induces apoptosis in the paratumor cirrhosis hepatocellular cell line QSG-7701 via activation of p38MAPK pathway and it differs in the normal liver cells from the hepatocellular carcinoma cells.</p>

Effects of experimental liver injury on the intestinal barrier in rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the effects of experimental liver injury on the intestinal barrier, and to evaluate the significance of plasma D(-)-lactate, diamine oxidase (DAO) and endotoxin in live injury.</p><p><b>METHODS</b>Fifty-five rats were randomized into the acute liver failure group (group C, n = 25), acute liver injury group (group B, n = 15), and control group (group A, n = 15). The concentrations of D(-)-lactate, DAO and endotoxin in plasma were detected by spectrophotograph. The morphology and subcellular structure were observed under optical microscope and transmission electron microscope.</p><p><b>RESULTS</b>Acute liver failure and acute liver injury models were established successfully. The concentrations of D(-)-lactate and DAO in the plasma of experimental groups (group B and C) were significantly higher than those in the control group (P less than 0.05); the concentration of intestinal DAO in experimental groups were significantly lower than that in the control group (P less than 0.05); the level of endotoxin in C group was significantly higher than that in group A and group B (P less than 0.05).</p><p><b>CONCLUSION</b>Liver injury induces hyperpermeability of the rat intestinal mucosal barrier, plasma D(-)-lactate and DAO are sensitive markers for early diagnosis of liver injury, plasma endotoxin may accelerate deterioration of liver function.</p>

Liver histopathology, clinical features and prognostic factors of primary biliary cirrhosis: an analysis of 60 cases / 中华肝脏病杂志

<p><b>OBJECTIVE</b>Clinical and liver pathological features of 60 primary biliary cirrhosis (PBC) patients were reviewed to identify prognostic factors in order to improve the diagnosis and treatment of the disease.</p><p><b>METHODS</b>The general conditions, clinical manifestations, serum biochemical and immunological changes, and liver pathological findings were assessed in 60 PBC patients. All cases were followed up and 5 variables were studied by univariate analysis; the variables linked with survival were included in a Cox model.</p><p><b>RESULTS</b>Forty-eight patients were females (80%), 12 were males (20%), and the mean age at their diagnoses was (52.5+/-9.4). The symptoms most frequently complained about were jaundice (61.6%), fatigue (51.6%), anorexia (43.3%) and pruritus (25%). Serum alkaline phosphatase (ALP) and glutamyl transpeptidase (GGT) levels were markedly elevated in the majority of the patients [(242.3+/-137.1) U/L and (250.6+/-216.1) U/L, respectively], whereas ALT and AST levels were mildly to moderately elevated [(185.8+/-269.1) U/L and (172.5+/-163.6) U/L, respectively]. Thirty-two patients (53.3%) had a total bilirubin level of > or = 34.2 micromol/L. Twenty-eight patients (59.5%) had elevated serum IgM and 41 patients (68.3%) were anti-mitochondrial antibody AMA/AMA-M2 positive. Forty-two of the 60 patients had liver biopsies. The liver pathological changes: 33.3% of the cases were in I or II stage and 66.6% in III or IV stage. The follow up results: Five patients died of liver failure or massive upper gastrointestinal bleeding; 45 were still alive; the average survival period was 3.92 years; 10 patients were lost in the follow-up. With multivariate analysis (Cox model), age, level of total bilirubin and the stage of the liver pathological changes were found to be independent factors linked to the survival of the patients.</p><p><b>CONCLUSION</b>PBC may not be a rare liver disease in China. The awareness to recognize PBC is important in making an early diagnosis and treatment.</p>

A comparative study on the reliability of grating projection measuring system in three-dimensional reconstruction of dental cast / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the reliability of a newly developed grating projection system 3DSS-STD-II by three-dimensional reconstruction of dental cast, so as to offer some evidence for dental computer aided design and computer aided manufacturing (CAD/CAM).</p><p><b>METHODS</b>Five groups' data of mandibular dentition cast from different angle: Occlusion, right lateral dentition, anterior dentition, left lateral dentition and posterior of the cast were scanned and acquired by 3DSS-STD-II new measuring system. The five groups of acquired data were then under simplification and combination process and the digital dental cast was finally reconstructed by the reverse engineering software Geomagic 6.0. After the reconstruction process, the plaster dental cast and digital reconstructed dental cast were then manually and digitally measured respectively by different items: Width of incisors, width of anterior dental arch, width of buccal segment, length of anterior dental arch and length of buccal segment. The manual process was undergone by vernier caliper and the digital process was by reverse engineering software. The statistical analysis was then undergone in order to evaluate the reliability, repeatability and scan-precision of the new grating projection system.</p><p><b>RESULTS</b>With the statistical analysis results, the grating projection system 3DSS-STD-II showed its good reliability and repeatability in three-dimensional reconstruction of dental plaster cast. There were no significant differences between the data acquired by 3DSS-STD-II digital scanning system and manual measurement by vernier caliper in the precision.</p><p><b>CONCLUSION</b>The new grating projection system of 3DSS-STD- II equipped with high reliability and fast speed can meet the need of the fast data acquisition and three-dimensional reconstruction of dental cast and CAD process.</p>

Effect of mold temperature on mechanical properties of Ti-Zr alloy castings / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of mold temperature on the mechanical properties of Ti-Zr alloy castings.</p><p><b>METHODS</b>Ti-Zr alloy was cast into a mold which was made of a zircon (ZrO2.SiO2) investment with a casting machine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300 degrees C, 600 degrees C) the Ti-Zr alloy was cast separately. The ultimate tensile strength (sigmab), 0.2% offset yield point strength (sigma0.2), and elongation to fracture (delta) were determined by a universal testing machine with 15 mm pre-marked gauge interval. The surface micro-structures of Ti-Zr alloy castings at three mold temperatures were observed by optical microscope.</p><p><b>RESULTS</b>At a higher mold temperature during casting, the tensile strength and yield strength of Ti-Zr alloy were significantly increased, while the elongations were significantly decreased. The micro-structure of the surface was different from the inner part. There was a reacted layer in the outermost surface. The thickness of reacted layers at the three mold temperatures was about 35.5 man (room temperature), 55.0 microm (300 degrees C) and 65.5 microm (600 degrees C), respectively. The inner part of microstructure composed of main a phases within the prior alpha grain boundaries.</p><p><b>CONCLUSION</b>The mold temperature is one of the major factors influencing Ti-Zr alloy mechanical properties. Comparing with Ti6Al4V alloy and Co-Cr alloy castings, Ti-Zr alloy is more suitable for denture frame.</p>