13 research outputs found
BUILDING AN INTERNATIONAL NETWORK EXCHANGE PROGRAM OF EDUCATION AND RESEARCH FOR GRADUATE COURSE STUDENTS IN LIFE SCIENCE AND BIOTECHNOLOGY
We proposed an "International Network Exchange Program of Education and Research for Graduate Course Students in Life Science and Biotechnology" to the Kansai University Special Research Fund 2007 in order to promote international student exchange in the Graduate School of Engineering. In this program, we have successfully sent 8 graduate students to study for about a month in Malaysia, Thailand, Indonesia, and Germany. We hope the result of our efforts will promote an acceleration of international student exchange in the Graduate School of Engineering.LIFE SCIENCE AND BIOTECHNOLOGY, 50th anniversary editio
Plasma-Assisted Synthesis of Multicomponent Nanoparticles Containing Carbon, Tungsten Carbide and Silver as Multifunctional Filler for Polylactic Acid Composite Films
Multicomponent nanoparticles containing carbon, tungsten carbide and silver (carbon-WC-Ag nanoparticles) were simply synthesized via in-liquid electrical discharge plasma, the so-called solution plasma process, by using tungsten electrodes immersed in palm oil containing droplets of AgNO3 solution as carbon and silver precursors, respectively. The atomic ratio of carbon:W:Ag in carbon-WC-Ag nanoparticles was 20:1:3. FE-SEM images revealed that the synthesized carbon-WC-Ag nanoparticles with particle sizes in the range of 20–400 nm had a spherical shape with a bumpy surface. TEM images of carbon-WC-Ag nanoparticles showed that tungsten carbide nanoparticles (WCNPs) and silver nanoparticles (AgNPs) with average particle sizes of 3.46 nm and 72.74 nm, respectively, were dispersed in amorphous carbon. The carbon-WC-Ag nanoparticles were used as multifunctional fillers for the preparation of polylactic acid (PLA) composite films, i.e., PLA/carbon-WC-Ag, by solution casting. Interestingly, the coexistence of WCNPs and AgNPs in carbon-WC-Ag nanoparticles provided a benefit for the co-nucleation ability of WCNPs and AgNPs, resulting in enhanced crystallization of PLA, as evidenced by the reduction in the cold crystallization temperature of PLA. At the low content of 1.23 wt% carbon-WC-Ag nanoparticles, the Young’s modulus and tensile strength of PLA/carbon-WC-Ag composite films were increased to 25.12% and 46.08%, respectively. Moreover, the PLA/carbon-WC-Ag composite films possessed antibacterial activities
Preparation of Chitosan-Coated Polyethylene Packaging Films by DBD Plasma Treatment
Polyethylene (PE) packaging films were coated with chitosan
in
order to introduce the antibacterial activity to the films. To augment
the interaction between the two polymers, we modified the surfaces
of the PE films by dielectric barrier discharge (DBD) plasma before
chitosan coating. After that the plasma-treated PE films were immersed
in chitosan acetate solutions with different concentrations of chitosan.
The optimum plasma treatment time was 10 s as determined from contact
angle measurement. Effect of the plasma treatment on the surface roughness
of the PE films was investigated by atomic force microscope (AFM)
while the occurrence of polar functional groups was observed by X-ray
photoelectron spectroscope (XPS) and Fourier transformed infrared
spectroscope (FTIR). It was found that the surface roughness as well
as the occurrence of oxygen-containing functional groups (i.e., CO,
C–O, and −OH) of the plasma-treated PE films increased
from those of the untreated one, indicating that the DBD plasma enhanced
hydrophilicity of the PE films. The amounts of chitosan coated on
the PE films were determined after washing the coated films in water
for several number of washing cycles prior to detection of the chitosan
content by the Kjaldahl method. The amounts of chitosan coated on
the PE films were constant after washing for three times and the chitosan-coated
PE films exhibited appreciable antibacterial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>. Hence, the obtained chitosan-coated PE films could be a promising
candidate for antibacterial food packaging
Utilization of agricultural waste to herbicide removal: Magnetic BEA zeolite adsorbents prepared by dry-gel conversion using rice husk ash–derived SiO2 for paraquat removal
This study presents a method that will allow for the sustainable utilization of rice husk ash-SiO2 (RHAS), an agricultural-waste–derived material, as a bulky solid SiO2 source in the zeolite beta (BEA)/Fe3O4 composite (magnetic RHAS-BEA) synthesis via a dry-gel conversion method for the removal of paraquat, a typical herbicide, from aqueous solutions. Ultrasonic waves were used to facilitate the formation of uniform Fe3O4-contained dry precursor gel before converting to the magnetic BEA zeolite composite for the first time. Magnetic RHAS-BEA was then characterized and compared with a non-magnetic sample (RHAS-BEA) using X-ray diffraction and field-emission scanning electron microscopy. In terms of adsorption, we found that paraquat had a high adsorption rate on the samples and conformed to a pseudo-second-order kinetic model. The adsorption behavior of paraquat on the synthesized RHAS-BEA and magnetic RHAS-BEA obeyed the Langmuir adsorption isotherm model. The synthesized adsorbents were reusable for at least four cycles, via thermal regeneration at 450 °C. The inclusion of Fe3O4 particles in magnetic RHAS-BEA disrupted neither the crystallization of the BEA zeolite nor the adsorption of paraquat and enabled easy collection via an external magnet