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Objective@# To evaluate the effect of heat treatment on the bonding strength of pure titanium formed by selective laser melting (SLM) and porcelain.@*Methods@#Ninety-six pure titanium specimens were laser machined to meet ISO 9693 standards. The specimens were divided into a heat treated group (A) and a nonheat treated group (B). According to the porcelain type, the specimens in groups A and B were divided into Super Ti22 (a), Titankeramik (b), and Triceram (c) groups. Then, according to sandblasting pressures of 0.25 MPa (1) and 0.45 MPa (2), they were further divided into Aa1, Aa2, Ab1, Ab2, Ac1, Ac2, Ba1, Ba2, Bb1, Bb2, Bc1, and Bc2 groups. The surface morphology and roughness of the sandblasted specimens were assessed using a laser scanning confocal microscope. After the porcelain was fused, the three-point bending titanium-porcelain bonding strength was tested. A stereomicroscope was used to characterize the titanium-porcelain interfaces and determine the mode of failure.@* Results@# The Vickers hardness of group A specimens (188.21 ± 11.94) was significantly lower than that of group B specimens (204.48 ± 6.32) HV (P<0.05). The roughness value in group A1 (2.90 ± 0.32) μm was significantly lower than that in group A2 (3.43 ± 0.43) μm (P<0.05). Specimens in group B1 (2.62 ± 0.08) μm were significantly smaller than those in group B2 (3.01 ± 0.06) μm (P<0.05). The bonding strength in group Aa1 was (33.75 ± 2.31) MPa, group Aa2 was (36.32 ± 1.44) MPa, group Ab1 was (39.82 ± 2.28) MPa, group Ab2 was (33.74 ± 1.53) MPa and group Ac2 was (38.63 ± 1.36) MPa, which was significantly higher than that in the corresponding groups Ba1 (29.65 ± 1.10) MPa, Ba2 (27.17 ± 2.24) MPa, Bb1 (27.29 ± 1.61) MPa, Bb2 (23.85 ± 0.97) MPa, and Bc2 (35.75 ± 1.93) MPa (P<0.05). With increasing sandblasting pressure, the bonding strength of the titanium ceramic in group Aa2 was significantly higher than in group Aa1, while that in group Ab2 was significantly lower than that in group Ab1 (P<0.05). In groups A, Bc1 and Bc2, the fracture model showed mixed failure, while in groups Ba1, Ba2, Bb1, and Bb2, the model showed interfacial failure.@* Conclusion @# The Vickers hardness of SLM titanium can be significantly reduced by heat treatment. SLM pure titanium after heat treatment is beneficial to combination of the three porcelain types and titanium. The titanium-porcelain bonding strength may be affected by sandblasting pressure.
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Objective @# To evaluate the effect of different surface treatments on the bonding strength between highly translucent zirconia and veneering porcelain and to provide a research basis for improving the zirconium porcelain bond strength between zirconium and ceramic material.@*Methods @# Thirty cylindrical zirconia blocks with 10-mm diameter and 10-mm height were prepared and divided into four groups (n=7), labeled as control group (C), sandblasting group (S), bonding group (B), and sandblasting and bonding group (SB). The surface morphology of zirconia before and after sandblasting was observed in the remaining two specimens. Group C was veneered (2 mm in height and 5 mm in diameter) with porcelain powder by layering after grinding. Group S was sandblasted after grinding. Group B was veneered with a thin layer of porcelain powder as bond coating. Group SB was sandblasted and veneered with a thin layer of porcelain powder. After sintering, the shear specimens were embedded, and a shear bond strength test was conducted. Statistical analysis was conducted to analyze the data. Fracture surface analysis was also performed to determine the failure modes by stereomicroscopy.@*Results @# The bonding strength of group C was 21.86 ± 3.18 MPa. For group S, it was 22.12 ± 3.06 MPa. For group B, it was 19.19 ± 1.46 MPa. Finally, for group SB, it was 27.76 ± 1.95 MPa. There was no significant difference in shear strength between group C, group S and group B. There was a significant difference in shear strength between each group and group SB (P < 0.05). Under a stereomicroscope, the observed fracture modes of each group were mainly mixed failure.@*Conclusion@#Sandblasting cannot significantly increase the bonding strength between zirconia and veneering porcelain. Veneering with a thin layer of porcelain powder as the bond coating has no obvious effect on the bonding strength. Sandblasting and veneering with a thin layer of porcelain powder as a bond coating can significantly improve the bonding strength between zirconia and veneering porcelain.
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The antitumor effect of calycosin has been widely studied, but the targets of calycosin against glioblastomas are stillunclear. In this study we focused on revealing c-Met as a potential target of calycosin suppressing glioblastomas. In thisstudy, suppressed-cell proliferation and cell invasion together with induced-cell apoptosis appeared in calycosin-treatedU251 and U87 cells. Under treatment of calycosin, the mRNA expression levels of Dtk, c-Met, Lyn and PYK2 wereobserved in U87 cells. Meanwhile a western blot assay showed that c-Met together with matrix metalloproteinases-9(MMP9) and phosphorylation of the serine/threonine kinase AKT (p-AKT) was significantly down-regulated by calycosin.Furthermore, overexpressed c-Met in U87 enhanced the expression level of MMP9 and p-AKT and also improved cellinvasion. Additionally, the expression levels of c-Met, MMP9 and p-AKT were inhibited by calycosin in c-Met overexpressed cells. However, an AKT inhibitor (LY294002) only effected on MMP9 and p-AKT, not on c-Met. These datacollectively indicated that calycosin possibility targeting on c-Met and exert an anti-tumor role via MMP9 and AKT.
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The effect of obesity on idiopathic central precocious puberty (ICPP) girls is still under discussion.The relationship between body mass index (BMI) and sexual hormone levels of gonadotropin-releasing hormone (GnRH) stimulation test in ICPP girls is controversial and the underlying mechanism is unclear.This study aims to further explore the independent effect of excess adiposity on peak luteinizing hormone (LH) level of stimulation test in ICPP girls and the role of other related factors.A retrospective cross-sectional study was performed on 618 girls diagnosed as having ICPP,including 355 cases of normal weight,99 cases of overweight and 164 cases of obese.The results showed that obese group had more progressed Tanner stage and no significant difference (P=0.28) in LH peak was found as basal LH value was used as a covariate.The obese group had higher total testosterone (TT),adrenocorticotrophic hormone (ACTH),17-α hydroxyprogesterone (17-αOHP) and androstendione (AN),with significantly increased fasting insulin (FIN) and homeostasis model of assessment for insulin resistance index (HOMA-IR).Stratified analysis showed inconsistency of the relationship between BMI-standard deviation score (BMI-SDS) and LH peak in different Tanner stages (P for interaction=0.017).Further smoothing plot showed linear and non-linear relationship between BMI-SDS and LH peak in three Tanner stages.Then linear regression model was used to analyze the relationship between BMI-SDS and LH peak in different Tanner stages,with and without different confounding factors being adjusted.In B2 stage,BMI-SDS was negatively associated with LH peak.In B3 stage,when BMI-SDS ＜1.5,as BMI-SDS increased,the level of LH peak decreased (model Ⅰ:β=-1.8,95％ CI=-4.7 to 1.1,P=0.214).When BMI-SDS ≥1.5,BMI-SDS was significantly positively associated with LH peak (model Ⅰ:β=4.5,95％ CI=1.7 to 7.4,P=0.002).In B4 stage,when BMI-SDS ＜1.5,BMI-SDS was negatively associated with LH peak (model Ⅰ:β=-11.6,95％ CI=-22.7 to-4.5,P=0.049).When BMI-SDS ≥1.5,BMI-SDS was positively associated with LH peak (model Ⅰ:β=-4.2,95％ CI=-3.3 to 11.7,P=0.28).It is concluded that there is an independent correlation between BMI-SDS and LH peak of stimulation test in ICPP girls,their relationships are different in different Tanner stages,and the effect of BMI-SDS can be affected by adrenal androgens,estradiol and glucose metabolism parameters.
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In previous study,glutaric acid (GA) induced apoptosis of primary striatal neuron in vitro.In order to investigate the neurotoxic effects of GA on neonatal rat corpus striatum and the possible mechanism,34 male pups were randomly assigned to NS group,low dose GA (LGA,5 μmol GA/g body weight) group and high dose GA (HGA,10 μmol GA/g body weight) group.These pups were subcutaneously administered with three injections from postnatal day 3 to 22 at 7:30 am,15:00 pm and 22:30 pm and killed 12 h after the last injection.Microscopic pathology in corpus striatum was evaluated by HE staining.The apoptotic cells were identified by TUNEL staining.The transcript levels of caspase-3,8,9,Bax,Bcl-2 were detected by using real-time PCR and the protein levels of procaspase-3 and the active fraction were evaluated by Westem blotting.In LGA and HGA groups,ventricle collapse,cortical atrophy by a macroscope and interstitial edema,vacuolations,widened perivascular space of bilateral striatum by a microscope were observed.TUNEL assay revealed that the apoptotic cells were increased in LGA and HGA groups.The transcript of caspase-3 was up-regulated to 2.5 fold,accompanied by the up-regulation of caspase-9,Bax and down-regulation of Bcl-2.The protein levels ofprocaspase-3 and the active fraction were up-regulated in LGA and HGA groups.The rat model for GA Ⅰ showed mitochondrial apoptotic pathway may be involved in the GA-induced striatal lesion.Further studies should be taken to investigate the underlying mechanisms.
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Methylmalonic aciduria (MMA) is a common inherited autosomal recessive disorder resulting from defects in the enzyme methylmalonyl CoA mutase (MCM,mut complementation group) or in the synthesis of the MCM cofactor adenosylcobalamin (cbl complementation groups).The defects in the mut complementation group accounts for the largest number of patients with isolated MMA.At least 200 mutations in the MUT gene on chromosome 6p12 have been identified in MMA patients until now.This study aimed to investigate the clinical characteristics of MMA and genomic variations in the MUT gene of Chinese patients.Genomic DNA was extracted from 18 patients who were diagnosed as having isolated MMA by gas chromatography/mass spectrometry (GC-MS),and from some of their parents as well.Amplification and direct sequencing of the MUT coding regions (exon 2-13) and their adjacent intronic consensus splice sites were performed in order to identify the disease causing mutations.In this group,six novel mutations in the MUT gene,c.424A＞G (p.T142A),c.786T＞G (p.S262R),c.808G＞C(p.G270R),c.1323_1324insA,c.1445-1G＞A and c.1676+77A＞C were identified.p.T142A and p.G270R were respectively detected at a heterozygous level in one patient.Two previously reported mutations,c.682C＞T (p.R228X) and c.323G＞A (p.R108H) were also found in this study.In addition,six previously described single nucleotide polymorphism (SNP),c.636A＞G (p.K212K),c.1495G＞A(p.A499T),c.1595A＞G (p.H532R),c.1992G＞A (p.A664A),c.2011G＞A (p.V671I) and c.1677-53A＞Gwere identified.In this study,we updated the spectrum of MUT mutations and identified the main MMA-causing mutations in Chinese MMA patients.
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smids were constructed suc-cessfully, and SARS-CoV encoding proteins could activate transcription and expression of hfgl2 gene.