Experimental-Computational Investigation of the Elastic Modulus of Mortar under Sulfate Attack.

External sulfate attack is an important factor causing a decrease in the mechanical properties of cement-based materials. In this paper, a computational prediction model of elastic modulus, considering the characteristics of sulfate corrosion from outside to inside and the influence of the interface transition zone (ITZ), was established to predict the elastic modulus of mortar under the external sulfate attack. Firstly, the backscattered electron (BSE) images of mortar and the algorithm of image threshold segmenting were used to determine a reasonable thickness of corroded ITZ. Secondly, the nanoindentation test was adopted to acquire the microscopic elastic parameters of phases (sand, cement, and ITZ) in corroded mortar. Moreover, the mortar mix proportion and Lu and Torquato's model were adopted to calculate the volume fractions of phases. Finally, a computational prediction model of elastic modulus of mortar under sulfate attack was proposed with homogenization methods. The results indicate that the thickness of corroded ITZ is 20 mm, and the error values of elastic modulus between the theoretical prediction results and the experimental results are within 8%, indicating that the macroscopic elastic modulus of corroded mortar can be precisely predicted by the computational prediction model of elastic modulus.

Mesoscale Finite Element Modeling of Mortar under Sulfate Attack.

In this paper, a 2D mesoscale finite element (FE) numerical model of mortar, considering the influence of the ITZ, was proposed to evaluate the corrosion of mortar in sodium sulfate. On the mesoscale, the corroded mortar was regarded as a three-phase composite material composed of sand, cement paste, and an interface transition zone (ITZ). Firstly, the volume fractions and mechanical parameters (elastic modulus, Poisson's ratio, and strength) of the mesoscale phases were obtained. Then, the cement paste and the ITZ were combined to form an equivalent matrix by homogenization methods, and the calibrated constitutive relations of the equivalent matrix were established. Subsequently, a two-dimensional (2D) random circular aggregate (RCA) model and a 2D random polygonal aggregate (RPA) model of corroded mortar were established using the random aggregate model. The failure process of corroded mortar specimens under uniaxial compression was simulated by the mesoscale FE numerical model. Comparing the simulation results with the measured stress-strain curves of the uniaxial compression test, it was found that the simulation results of the 2D RP model were closer to the experimental results than those of the 2D RC model. Meanwhile, the numerical simulation results were in good agreement with the experimental results, and the error values of peak stress between the simulation results and the measured results were within 7%, which showed that the 2D mesoscale FE model could accurately predict the results of a uniaxial compression test of a mortar specimen under sulfate attack.

The prognostic role and reduced expression of FOXJ2 in human hepatocellular carcinoma.

The current study aimed to investigate the potential role of the FOXJ2 (forkhead box J2) protein in the pathology of hepatocellular carcinoma (HCC). Western blotting was performed to determine the expression levels of FOXJ2 in HCC tissues and HCC cells. Specimens from 110 patients with HCC undergoing hepatic resection were evaluated for FOXJ2 expression using an immunohistochemical assay. The correlation between FOXJ2 expression and clinicopathological factors of the patients was determined by statistical analysis to determine the prognostic merit of FOXJ2 expression in HCC. The detailed involvement of FOXJ2 in the regulation of HCC proliferation was further investigated using FOXJ2­targeting small interfering RNA (siRNA). FOXJ2 protein was identified to be significantly downregulated in HCC tissues compared with adjacent normal liver tissues. Immunohistochemical analysis demonstrated that the expression of FOXJ2 was negatively correlated with Ki­67 levels in HCC specimens (r=­0.679, P<0.001). Furthermore, statistical analysis indicated FOXJ2 expression was significantly associated with histological differentiation (P=0.005), the size of largest tumor (P=0.002) and metastasis (P=0.036). Using Kaplan­Meier analysis, it was demonstrated that high FOXJ2 expression levels predicted significantly improved patient survival rates compared with low FOXJ2 expression levels (P<0.001). In addition, it was observed that interference of FOXJ2 expression using siRNA oligos led to the promotion of proliferation of HepG2 cells. FOXJ2 was markedly downregulated in HCC tissues. The expression of FOXJ2 was correlated with tumor size, histological differentiation and metastasis. Low expression levels of FOXJ2 predicted poor prognosis for patients with HCC, suggesting that FOXJ2 may be a candidate prognostic marker of HCC. Depletion of FOXJ2 caused the promotion of HCC cell proliferation, implicating that FOXJ2 may serve an inhibitory role in the regulation of HCC cell proliferation.

TGF-ß induces HLA-G expression through inhibiting miR-152 in gastric cancer cells.

BACKGROUND: Mounting evidences have showed the important role of transforming growth factor-ß (TGF-ß) in immunological surveillance of tumors. Some studies have also indicated human leukocyte antigen (HLA)-G-associated immune escape involving TGF-ß management in gastric cancer (GC). However, the mechanism underlying it is unclear. This study aims to verify the correlations between HLA-G and TGF-ß, involving the potential targeting of miR-152 on HLA-G. RESULTS: TGF-ß and HLA-G levels were analyzed in blood samples from twenty GC patients with ELISA assays, while TGF-ß showed directly proportional to HLA-G levels in GC patients, and TGF-ß induced HLA-G up-regulation was also confirmed in GC cell lines. Furthermore, miR-152 expression could be inhibited by TGF-ß, and the negative post-transcriptionally regulation of miR-152 on HLA-G was also demonstrated through gain- and loss-of-function studies. Besides, miR-152 overexpression repressed HLA-G up-regulation induced by TGF-ß. And, miR-152 expression levels showed inversely proportional to both HLA-G and also TGF-ß levels in GC patients. CONCLUSION: TGF-ß could induce HLA-G expression in GC by inhibiting miR-152, involving its negative regulation on HLA-G. Since TGF-ß induced HLA-G up-regulation plays important role in immune escape, a potential application of miR-152 was suggested in GC treatment, or miR-152 might be one potential biomarker for GC.

Long non-coding RNA HOTAIR promotes HLA-G expression via inhibiting miR-152 in gastric cancer cells.

Recent studies have shown that the long non-coding RNA HOTAIR plays critical roles in tumor biology, including cancer progression and metastasis. However, the potential biological role HOTAIR in tumor escape remains undefined. Here, HOTAIR expression was measured in sixty paired gastric cancer (GC) tissue samples by real-time PCR, and then subjected to correlation analysis with human leukocyte antigen (HLA)-G levels which show close links with tumor escape mechanisms. Significant HOTAIR overexpression was observed in GC tissues, as well as strong positive correlations with HLA-G levels in both tissue and peripheral blood samples, detected by real-time PCR and ELISA assays respectively. Further gain- and loss-of-function studies indicated that HLA-G could be upregulated HOTAIR at both mRNA and secretion levels in vitro. On the other hand, bioinformatics analysis indicated the interaction between HOTAIR and miR-152, which shows potential regulation on HLA-G. And, altered miR-152 expression in GC tissues was also identified, and showed negative correlation with HOTAIR expression. Moreover, the negative regulation of miR-152 on HLA-G was verified in GC cells, while miR-152 induced decrease of HLA-G 3'UTR activity could be attenuated by HOTAIR co-overexpression with the assistant of mutation studies. Therefore, it was concluded that HOTAIR overexpression might also get involved in tumor escape mechanisms, involving HLA-G upregulation via inhibiting miR-152. Furthermore, this study recommended the potential application of HOTAIR in GC immunotherapy for better prognosis and improved survival.

[Quantitative analysis of plasma Epstein-Barr virus (EBV) DNA for monitoring of recurrence and metastasis in nasopharyngeal carcinoma patients after radiotherapy].

BACKGROUND & OBJECTIVE: Nasopharyngeal carcinoma (NPC) is closely related to Epstein-Barr virus (EBV) infection. Recently, it was reported that EBV DNA could be detected in the plasma or serum of NPC patients, but the clinical significance of EBV DNA concentration for monitoring of tumor recurrence and metastasis in NPC patients after radiotherapy has not been reported. This study was designed to quantitatively analyze the plasma EBV DNA concentration in NPC patients after radiotherapy, and to evaluate its application for monitoring of tumor recurrence and metastasis. METHODS: Ninety NPC outpatients after radiotherapy in Cancer Center, Sun Yat-sen University were followed up. The plasma EBV DNA were analyzed by using fluorescent quantitative PCR technique, and the quantity of plasma EBV DNA were compared between recurrent and clinical remission NPC patients. RESULTS: Ninety-six point seven percent (29/30) of recurrent and metastatic patients were detectable for plasma EBV DNA, with median concentration of 2650 copies/ml (range:0-5900000), whereas only 12%(7/60) of the clinical remission patients were detectable for plasma EBV DNA, with median concentration of 0 copy/ml (range:0-71000). The detectable proportion and concentration in recurrent and metastatic NPC patients were significantly higher than that in clinical remission NPC patients (P< 0.01). Three of the clinical remission NPC patients with elevated EBV DNA copy were confirmed for tumor local recurrence or metastasis after further 3-4 month follow-up. CONCLUSION: The results suggest that plasma EBV DNA detection may be a sensitive tumor marker for monitoring tumor recurrence and metastasis of NPC patients after radiotherapy.