Water Absorption of Poly(lactic acid) Nanocomposites: Effects of Nanofillers and Maleated Rubbers

Injection-molded poly(lactic acid)/organo-montmorillonite (PLA/OMMT) and poly(lactic acid)/ nano-precipitated calcium carbonate (PLA/NPCC) were exposed to a water absorption test at 30°C for 70 days. The analysis was focused on the water diffusion kinetics and impact strength changes induced by the hydrolysis. The diffusion exponent (n) values of all the PLA samples are less than 0.5, indicating the Fickian diffusion model (case I) is obeyed. Adding nanofillers and maleated rubbers (SEBS-g-MAH or EPR-g-MAH) increased equilibrium moisture content but decreased diffusion coefficient values of PLA. The recoverability and retention-ability of the maleated rubbers toughened PLA/OMMT and PLA/NPCC after water absorption are excellent.     

Superplastic elongation characteristic of fine grained magnesium alloy ZK60

This paper employs simple rolling process plus annealing to refine the grain size of magnesium alloy ZK60. This goal is effectively achieved, obtaining grains as fine as ∼3.7 μm. Such a specimen shows an elongation of 642%, and its ultimate fracture surface exhibits intergranular separation and significant grain growth. Additionally, the effects of the specimen’s geometry and tensile test axis with respect to the rolling direction on superplastic elongation is studied, which has not been done before.     

Hydroxygenkwanin Increases the Sensitivity of Liver Cancer Cells to Chemotherapy by Inhibiting DNA Damage Response in Mouse Xenograft Models

Molecules involved in DNA damage response (DDR) are often overexpressed in cancer cells, resulting in poor responses to chemotherapy and radiotherapy. Although treatment efficacy can be improved with the concomitant use of DNA repair inhibitors, the accompanying side effects can compromise the quality of life of patients. Therefore, in this study, we identified a natural compound that could inhibit DDR, using the single-strand annealing yeast-cell analysis system, and explored its mechanisms of action and potential as a chemotherapy adjuvant in hepatocellular carcinoma (HCC) cell lines using comet assay, flow cytometry, Western blotting, immunofluorescence staining, and functional analyses. We developed a mouse model to verify the in vitro findings. We found that hydroxygenkwanin (HGK) inhibited the expression of RAD51 and progression of homologous recombination, thereby suppressing the ability of the HCC cell lines to repair DNA damage and enhancing their sensitivity to doxorubicin. HGK inhibited the phosphorylation of DNA damage checkpoint proteins, leading to apoptosis in the HCC cell lines. In the mouse xenograft model, HGK enhanced the sensitivity of liver cancer cells to doxorubicin without any physiological toxicity. Thus, HGK can inhibit DDR in liver cancer cells and mouse models, making it suitable for use as a chemotherapy adjuvant.     

Effects of fluorine-implanted treatment on Ba0.7Sr0.3TiO3 films

The effects of F-ion implantation on the leakage and dielectric properties of the Ba_0.7Sr_0.3TiO₃ (BST) films were investigated. The BST film implanted with 1×10¹⁵ cm^–2 shows the optimum leakage performance. The leakage current density can be decreased by one order of magnitude as compared to that of the non-implanted sample at an applied voltage of 2 V. On increasing the implanted dose from 5×10¹⁴ to 5×10¹⁵ cm^–2, the dielectric constant first increases and then decreases due to the deteriorated crystallinity. It is found that the suitable F-ion dose can reduce the –OH contaminants and improve the dielectric and leakage properties.     

Technical Approach to Simplify the Purification Method and Characterization of Microbial Transglutaminase Produced from Streptoverticillium ladakanum

In order to fast and economically purify MTGase from Streptoverticillium ladakanum , a stepwise elution method was developed and compared with linear gradient elution method. MTGase was purified to electrophoretical homogeneity by using CM Sepharose CL-6B and Blue Sepharose Fast Flow chromatographies by linear gradient or stepwise methods. The recovery of MTGase by linear gradient and stepwise methods were 68.4% and 81.0%, respectively. The optimal temperature and pH were 40 °C and 5.5, respectively. It was stable at pH 5.0 to 7.0 and had a rate constant (KD) of 6.21 °o 10^-5 min^-1 for thermal inactivation at 45 °C. The purified MTGase was activated by K⁺ Na⁺, Ca²⁺, Mn²⁺, and Mg²⁺, not affected by Fe³⁺, EDTA, but inhibited by Cu²⁺, Zn²⁺, Hg²⁺, Ni²⁺, Co²⁺, Cd²⁺, PCMB, NEM, IAA, and PMSF. A simple stepwise method was developed for the purification of MTGase from S. ladakanum.     

Electrical filtration of dielectric liquids from semiconducting and conducting particles

Certain problems of electrical purification of dielectric oils (for example, transformer oil) to remove micron-sized semiconducting and conducting particles are considered. A solution of the problem concerning the dependence of the particle concentration on the time in the output of an electrofilter both at a zero and a nonzero flow rate is given. It is shown that, in both cases, the mathematical structure of the solutions is the same. Thus, it is possible to use the same formulas with the parameters of the given mode. Physical and mathematical interpretations of the experimental results are proposed. Equations for the theoretical dependences corresponding to the experimental ones are obtained and their graphs are plotted. The experimental data, which are in good agreement with the theoretical results, are generalized using dimensionless logarithmic equations.     

Freeze-form extrusion fabrication of functionally graded materials

Presented in this paper is a novel additive manufacturing technology for making three-dimensional parts with functionally graded materials (FGMs), called Freeze-form Extrusion Fabrication (FEF). The system development included a triple-extruder mechanism, extruder modeling and control, pastes extrusion planning for desired composition gradients, and software coding for motion and extrusion control. The effectiveness of the developed FEF system was demonstrated first by fabricating limestone (CaCO₃) parts with graded colors and then by fabricating ‘green’ parts with graded compositions between alumina (Al₂O₃) and zirconia (ZrO₂). The fabricated part went through post-processing, and the sintered part was analyzed using energy dispersive spectroscopy (EDS) to determine its material compositions.     

Graphite-based indirect laser sintered fuel cell bipolar plates containing carbon fiber additions

Critical considerations for laser sintered (LS) graphite bipolar plates are the strength of the parts in the green, brown and finished states as well as the final part electrical conductivity. The effect of 0-26 volume percent chopped carbon fiber (CF) on strength and electrical conductivity of LS graphite bipolar plates was evaluated. Fiber additions improved the green and brown strength significantly. Finished part flexural strength increased from 35 MPa to almost 50 MPa with CF additions. The electrical conductivity of finished parts was lowered by CF additions.     

Integrating data mining with KJ method to classify bridge construction defects

This paper tries to analyze common bridge construction defects, classify them into appropriate groups, and redefine them as a precautionary measure and means to improve quality in bridge construction. For this purpose, data on bridge construction since January 2007 were obtained from the evaluation report of the Public Construction Committee (PCC) of Taiwan. Bridge construction defects were classified according to their characteristics. A constraint-based clustering method and affinity diagram (KJ method) are proposed and used. This method can simultaneously treat mixed data types; moreover, it can incorporate user-specified constraints. The quality or safety issues, the unit-in-charge (Government authorities/project owners/contractor), and the properties of the defects (construction/audit/documents/others) are the sorting attributes. The constraint is avoiding empty clusters or clusters having very few objects. The results revealed five major defect classifications: safety and environment, construction site defects, supervision/control process, construction quality documents, and others.