Advanced Materials Research Vols. 1120-1121

Abstract: In this study, surface modification of stainless steel flat plates was performed using nanoscale bilayers assembly method to increase the surface’s hydrophilicity and enhance evaporation. Thin layers of SiO₂ nanoparticles layered onto the stainless steel surfaces were used to modify their surface properties, and the relationship between the number of layers (0~20) and water’s hydrophilicity (surface tension) was investigated. The effects of modification on evaporation were then tested using de-ionized water. According to experimental results, surface modification was able to reduce the contact angle of water on stainless steel flat plate from the unmodified 87o to 7o at 18 layers, significantly increasing the hydrophilicity of the surface. Evaporation experiments show that the evaporation heat transfer enhancement for droplets on stainless steel plates is at least 300%.Keywords: bilayers assembly, hydrophilicity, surface modification, evaporation performance

Abstract: Ni60AA and DZ-WC-12Co cemented carbide layer was prepared on 45 steel by high-speed flame spraying, then remelted by 5KW continuous wave CO2 laser. The micro-structure was analyzed by Olympus GX51 .micro hardness and the micro hardness was measured by HXY-1000TAY micro hardness meter. The wear resistant of coating was tested by MM-W1B vertical universal testing machine. The results showed that laser melting significantly eliminate the carbide layer unmelted carbide particles, holes and cracks and other defects, the micro-structure is finer and more uniform. After laser re-melted, the average micro hardness of hard alloy layer is up to 647HV, which is five times of the matrix. Under the experimental conditions, the friction coefficient of hard alloy layer drops from 0.1373 to 0.0948 by 31%.The wear-resistance of cemented carbide layer is improved by laser melting.

Abstract: Objective: To identify and testify the cytotoxicity of the EGFR targeting drug TGFa-SAP conjugated and synthesized with N-succinimidyl-3 (2-pyridyldithio) propionate on human hepatoma cell line BEL-7404 cells and proliferating vascular smooth muscle cells. Methods: Conjugation of saporin with TGFa was accomplished after derivatization of TGFa and saporin with N-succinimidyl-3 (2-pyridyldithio) proprionate and the purification of the conjugate was achieved through Eppendorf Centrifugal Filter. Cytotoxicity assays were measured by MTS assays. The value of Thymidine incorporation in BEL-7404 cells was measured by ³H-thymidine uptake. Results: Cytotoxicity assays testified that TGFa-SAP conjugate could remarkably inhibit the proliferation of human hepatoma cell line BEL-7404 cells in vitro. The value of thymidine incorporation of BEL-7404 cells in TGFa-SAP groups significantly decreased compared with the control group (P<0.05), and it had dose-dependence on TGFa-SAP’s concentration. But Saporin could not affect BEL-7404 cells even at higher level (10^-5). TGFa-SAP conjugate had effective cytotoxicity on proliferating vascular smooth muscle cells, also. Conclusion: The results indicated that the conjugated EGFR targeting drug TGFa-SAP had effective cytotoxicity not only on BEL-7404 cells, but also on proliferating vascular smooth muscle cells, as a potential bioactive stent coating material.

Abstract: Medulloblastoma (MB) is one of the most common malignant tumors in pediatric brain. The genesis and development of MB are related to abnormal and persistent activation of the Wnt/β-catenin abnormal and NF-κB signaling pathway. The VEGF, as the main target gene regulated by the crosstalk between the two signaling pathways, is closely related to MB. In previous studies, We found that the genesis of MB is associated with the abnormal expression of key molecular GSK-3β,β-catenin and downstream target gene PPAR-gamma in Wnt /β-catenin signaling pathway.It also found that, there have abnormal expression of VEGF-A, C and its receptor VEGFR-2 in MB, and positively correlate with β-catenin. curcumin has anti-angiogenic function, but the exact mechanism is unclear. Combining with the early research findings and the latest literatures, we hypothesized that curcumin can inhibit the expression of VEGFs/VEGFRs by blocking the Wnt/β-catenin and NF-κB signaling pathway.

Abstract: More and more studies have reported that epithelial-mesenchymal translation (EMT) plays key roles not only on genesis, development and metastasis, but also on drug-resistance of chemotherapy of tumor. Meanwhile, the fact that beta-catenin transfer from membrance and cytoplasm to nucleus is major steps in process of EMT [1]. Research found that Genistein would suppress Wnt/beta-catenin signal pathway though inhibiting beta-catenin translation [2]. Furthermore, our research showed that Genistein could decrease the expression of GSK-3beta in ovarian carcinoma cell SKOV3. Beta-catenin and GSK-3beta are important factors of EMT, which indicated that Genistein would regulate EMT signal pathway through beta-catenin and GSK-3beta, but the mechanism is not clear. So, there has been great interest in understanding the molecular mechanisms on the effect of Genistein.

Abstract: To prolong the bioactivity of eprinomectin (EPM), a batch of EPM-loaded PLGA microspheres were fabricated by a solvent evaporation method. The morphology of resultant microspheres was observed with an S-4800-I scanning electron microscope (SEM). The EPM release behaviors were investigated with a dialysis method and fitted with Zero-order, First-order, and Higuchi dynamical models. The optimum formula, C_PVA 2.0 w/v%, stirring rate 1, 200 r/min, C_PLGA 4.0 wt%, and oil/water ratio 1/250, was obtained from single-factor experiments. SEM images suggested that the resultant microspheres were monodispersed spheres with a few micropores on their surfaces. Furthermore, more pores and hollows were observed in the degraded PLGA matrix. EPM-loaded PLGA microspheres showed the maximum release amount in the mixture of alcohol/PBS (4/6, v/v). The release process lasted for 30 d, which increased the bioactivity and insecticidal efficacy of EPM. Besides, microspheres with the diameter of 50 μm showed a better release behavior than those from 100 μm and 150 μm ones. Therefore, such method had a promising application on sustained release of veterinary medicine.

Abstract: The composite tubular scaffolds with highly oriented nanofibers used for vascular repair could improve the biomechanical properties of tubular scaffolds, satisfying the biomechanical requirement for the change of blood pressure and conducing to cell adhesion, migration and proliferation. The tubular scaffolds from poly(ε-caprolactone)(PCL) and silk fibroin (SF) composite nanofibers were successfully fabricated through electrospinning using cylindrical roller with an outer diameter (OD) of 3.0 mm. The influences of the collecting rotatation speeds on electrospun PCL/SF nanofibers orientation and radial/axial mechanical properties of the scaffolds were investigated. The results revealed that the electrospun PCL/SF tubular scaffolds fabricated at 1500 and 2000 r/min (linear velocity of 2.1, 2.8 m/s, respectively) possessed good arrangement around the circumferential direction of roller and sufficient radial strength and suture strength. The electrospun PCL/SF tubular scaffolds with circumferential-direction structure as a new vascular graft may be useful in vessel tissue engineering.

Abstract: Cholesterol metabolism plays an important role in pathogenesis of Alzheimer’s disease (AD). Curcumin has been reported to decrease cholesterol in serum through increasing the cholesterol efflux transporter ATP-binding cassette transporter A1 (ABCA1) expression, but the underlying mechanisms are not fully understand yet. To investigate the effects of curcumin on the activity of calcineurin and the expression of ABCA1 in vitro, N2a/APP695swe cells were treated with curcumin at 5 umol/L for 24 h, or with the calcineurin activity inhabitor CyclosporinA (CsA) at 0.5 umol/L for 48 h. Our findings showed that curcumin could increase the expression of the ABCA1 at mRNA and protein levels, furthermore, it could inhibit the calcineurin activity, CsA also could increase the expression of the ABCA1 at mRNA and protein levels. These findings suggest that curcumin may upregulate the expression of ABCA1 via inhibiting the calcineurin activity in N2a/APP695swe cells.

Abstract: Viscosity of raw sugar solution is an important factor affect the smelting process. This paper researched the changes and rules of raw sugar solution intrinsic viscosity under the treatment of turbine cavitation. Different operating parameters such as the raw sugar solution (0.10 g/mL, 0.15 g/mL, 0.20 g/mL, 0.25 g/mL, 0.35 g/mL, 0.45 g/mL), outlet pressures (0.1 MPa, 0.2 MPa, 0.3 MPa, and 0.4 MPa), solution temperature (30 °C, 40 °C, 50 °C, 60 °C and 70 °C), and treatment time (1 min, 2 min, 5 min, 10 min, and 20 min) were investigated. The experimental results show that: with the increase of the concentrations, intrinsic viscosity decrease rate reduced gradually; with the increase of the outlet pressure, intrinsic viscosity decrease rate increased gradually; with the increase of solution temperature, intrinsic viscosity decrease rate increased gradually; with the increase of cavitation time, intrinsic viscosity decrease rate increased gradually, but the increased rate is decreased, and at the beginning of the cavitation, the intrinsic viscosity decrease rate decreased faster.

Abstract: To optimize the prescription of tanshinone IIA lipid microspheres by central composite design method, and evaluate the quality. Through evaluating average particle size, stability constant and the encapsulation efficiency of the lipid microsphere to investigate the concentration of the egg yolk lecithin and the poloxamer and the percentage of Soybean oil in the total oil phase which may impact the properties of tanshinone IIA lipid microsphere. Building the mathematic relation between the index and factor by the binomial expression, according to the best mathematical model of the evaluation indicators to describe response surface and then to use response surface method to predict the best prescription which will be analysed. According to the prescription optimization to prepare tanshinone IIA lipid microsphere and evaluate its quality. The results showed that each index of the binomial equation fitting is good, the correlation coefficient of the average particle size, stability constant and the encapsulation efficiency are 0.97, 0.92 and 0.84 respectively. The optimized prescription is as follows: egg yolk lecithin1.38 g, F68 0.19 g, LCT 2 g, MCT 18 g, all the indexes of the optimized prescription are similar to the target values.