Xiaodong (Alice) Wang

Chemotherapy and Radiotherapy Downregulate the Activity and Expression of DNA Methyltransferase and Enhance Bcl-2/E1B-19-kDa Interacting Protein-3-Induced Apoptosis in Human Colorectal Cancer Cells

Bcl-2/E1B 19-kDa interacting protein 3 (BNIP3) is a proapoptotic protein whose expression level is often low in colorectal cancer (CRC) cells due to the BNIP3 gene promoter DNA methylation by DNA methyltransferase (DNMT). It is known that chemotherapy and radiotherapy suppress CRC through inducing tumor apoptosis. However, the molecular mechanisms underlying chemotherapy and radiotherapy-induced apoptosis of CRC cells are not well defined. In this study, we observed that the expression level of BNIP3 in colon cancer cells was significantly increased by treatment with therapeutic agents and radiation in vitro. The BNIP3 protein level in CRC tissues from patients who received preoperative concurrent chemotherapy was significantly higher than in those who received surgery alone. Furthermore, treatment with chemotherapeutic agents and radiation significantly decreased the DNMT1 expression level and enzymatic activity. Both expression level and activity of DNMT1 were inversely correlated with the expression level of BNIP3 in colon carcinoma cells after treatment with chemotherapeutic agents and radiation. Consistent with increased BNIP3 expression, chemotherapeutic agents and radiation induced colon carcinoma cell apoptosis in a dose-dependent manner. Based on these observations, we conclude that chemotherapy and radiotherapy inhibit DNMT1 expression to upregulate BNIP3 expression to promote CRC cell apoptosis. And, BNIP3 may play a role in the caspase-dependent apoptosis pathways, mainly during treatment with chemotherapy and radiotherapy.

Synthesis and characterization of poly-aluminum silicate sulphate (PASS) for ultra-low density fiberboard (ULDF)

Poly-aluminum silicate sulphate (PASS) was synthesized in a mixed aqueous solution of sodium silicate and aluminum silicate via a sol–gel method for use in ultra-low density fiberboard (ULDF). The preparation conditions were optimized by using response surface methodology. The effects and interactions of the Si/Al molar ratio (X1), pH value (X2) and temperature (X3) on the internal bond strength of ULDF were investigated. Research showed that the optimum internal bond strength (10.23 ± 0.64 kPa) was obtained under a Si/Al molar ratio of 2 : 1, pH value of 8, and a temperature of 50 °C. Analyses of the Fourier transform infra-red spectroscopy spectra confirmed that Al–O–Si bonds were formed between polysilicate and Al or its hydrolysate. The particle size analysis showed that the average size of PASS was 7.52 μm. Some of the PASS entered the cell wall and made a contribution to the improvement of the mechanical properties of ULDF.

Hybrid composites of polyvinyl alcohol (PVA)/Si–Al for improving the properties of ultra-low density fiberboard (ULDF)

The hybrid composites of polyvinyl alcohol (PVA)/Si–Al were synthesized to improve the thermostability and mechanical properties of ultra-low density fiberboard (ULDF). Their physical and chemical properties were tested by using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometry, thermogravimetric analysis (TGA), and a microcomputer control electronic universal testing machine. Microstructure results indicated that the distribution of inorganic fillers on the surface of ULDF was improved by the PVA. Analysis of chemical bonds and crystallinity of materials showed that part of the PVA reacted with Si–Al sol, and the other was physically crosslinked in the composite. The thermostability of ULDF decreased with the increasing content of PVA, but the mechanical properties increased. Combined with the TGA and mechanical properties results, a reasonable content of PVA (30%) was obtained. Under this condition, the modulus of rupture, modulus of elasticity, and the internal bond strength of ULDF were 0.35, 24.86, and 0.038 MPa, respectively.

Engineered Wood in Cold Climate - Application to Monitoring of a New Swedish Suspension Bridge

Engineered wood is increasingly used in large structures in Europe, though little is known of its behavior in cold climate. This paper presents the structural health monitoring (SHM) system of a newly built suspension bridge with a deck of glulam timber as well as a bond stability study regarding cold climate performance of engineered wood. The bridge is located in Skellefteå in northern Sweden, and it connects two parts of the city situated on opposite shores of the Skellefteå river. In this ongoing study of the timber-bridge, a structural health monitoring system is employed to verify structural design and long-term performance. This 130m-span bridge is monitored using GNSS receivers, MEMS accelerometers, laser positioning systems, wireless moisture content sensors, strain gauges and weather stations. Data from the monitoring systems is analyzed regarding accuracy, complexity, costs and reliability for long time use. Engineered wood application in bridges, sports centers and timber buildings are discussed. Bond stability of glulam structures in cold climate is also examined in a range of experiments ranging from small glued wood joints to full size glulam bridge performance over time. From an engineered wood material point of view, the study is relevant to cold regions such as Scandinavia, Canada, Alaska, Russia, and the northern parts of China and Japan etc. The engineered wood constructions in these areas will be exposed to low temperature in a quite long period each year. The goal is to determine how engineered wood behaves when exposed to temperatures between 20 °C to -60 °C.