No abstract

The structured adsorption filter material is one of the ways to enhance the practical applicability of powdered adsorbents, which have limitations in the real water treatment process due to difficulty in the separation process. In this study, three-dimensional (3D) printing technology was applied to prepare filter materials for water treatment processes. A 3D-printed graphene-oxide (GO)-based adsorbent is prepared on a polylactic acid (PLA) scaffold. The surface of the PLA scaffold was modified by subjecting it to strong alkaline or organic solvent treatment to enhance GO doping for realizing effective adsorption of cationic dye solutions. When subjected to 95% acetone treatment, the structural properties of PLA changed, and particularly, two main hydrophilic functional groups (carboxylic acids and hydroxyls) were newly formed on the PLA through cleavage of the ester bond of the aliphatic polyester. Owing to these changes, the roughness of the PLA surface increased, and its tensile strength decreased. Meanwhile, its surface was doped mainly with GO, resulting in approximately 75% methylene blue (MB) adsorption on the 3D-printed GO-based PLA filter. Based on the established optimal pretreatment conditions, a kinetic MB sorption study and an isotherm study were conducted to evaluate the 3D-printed GO-based PLA filter. The pseudo-second-order model yielded the best fit, and the MB adsorption was better fitted to the Langmuir isotherm. These results suggested that chemical adsorption was the main driver of the reaction, and monolayer sorption occurred on the adsorbent surface. The results of this study highlight the importance of PLA surface modification in enhancing GO doping and achieving effective MB adsorption in aqueous solutions. Ultimately, this study highlights the potential of using 3D printing technology to fabricate the components required for implementing water treatment processes.

 -Aminobutyric acid(GABA) is a four carbon non-protein amino acid that has several well-known physiological functions, such as a postsynaptic inhibitory neurotransmitter in the brain and induction of hypotensive and tranquilizer effects. A lactic acid bacterium was isolated from button mushroom bed, which is showing high GABA productivity by TLC or HPLC analysis. The strain was identified as Lactobacillus hilgardii by analysis of 16S rDNA gene sequence. When the maximum production of GABA by L. hilgardii was investigated with various concentration of monosodium glutamate, the yield of GABA reached to be 53.65 mM at 1% mono sodium glutamate (MSG) in flask cultivation. A Glutamate decarboxylase (GAD) enzyme, which was known to convert MSG to GABA, was purified from a cell-free extract of L. hilgardii and the molecular weights of purified GAD was estimated to 60,000 by SDS-PAGE. The optimum pH and temperature of GAD were at pH4.6 and at 37 o C, respectively. The GAD activity was increased by the addition of sulfate ions such as ammonium sulfate, sodium sulfate and magnesium sulfate, indicating that the increase of hydrophobic interaction causes the increase of GAD activity.

To clarify the role of stem cells in hepatocarcinogenesis, the expression of epithelial cell adhesion molecule (EpCAM) and proliferating cell nuclear antigen (PCNA) was investigated in mouse hepatic tumors and embryonic cell lineages. Ten ICR mice were treated with diethylnitrosamine (DEN) at 14 days of age and sacrificed at 36 weeks subsequent to DEN treatment to obtain the hepatic tumors. Mouse embryonic stem cells, hepatic progenitor cells and hepatocyte-like cells, representing 0, 22 and 40 days of differentiation, respectively, were treated in vitro with DEN at four doses (0, 1, 5 and 15 mM; G1, G2, G3 and G4, respectively) for 24 h and RNA was isolated. A total of 71 hepatic tumors were obtained from the DEN-treated mice. EpCAM expression was increased mainly in hepatic tumor cells, although it was also detected in the surrounding visually normal cells. Double staining showed that EpCAM and PCNA were co-expressed in numerous tumor cells. In vitro, EpCAM expression was significantly different for G4 at day 0 (P<0.01) and for G2, G3 and G4 at day 40 (P<0.01) compared with the control (G1) at the corresponding time-point. PCNA expression was significantly different for G3 and G4 at day 0 (P<0.01), for G2, G3 and G4 at day 22 (P<0.01) and for G2 at day 40 (P<0.01) compared with G1 at the corresponding time-point. In summary, the expression of EpCAM and PCNA was increased in DEN-induced tumors and the expression of EpCAM and PCNA was altered by DEN treatment in cultured cells. This suggests that EpCAM expression may be modulated in the progeny of adult liver stem cells during their differentiation toward hepatocytes and may be increased during DEN-induced hepatocarcinogenesis.

In this study we showed that although an inverse correlation existed between ICP and the third ventricle index only in patients with non-communicating hydrocephalus due to obstruction of the third ventricle, cerebral ventricle indices based on brain CT scan were non-reliable predictors of ICP in hydrocephalic patients.