• Polymer(Korea)
• /
• v.36 no.4
• /
• pp.486-493
• /
• 2012

Photocurable sulfonated polyimide (SPI) polyelectrolyte containing chalcone group was prepared and fabricated on an alumina electrode pretreated with chalcone-containing silane-coupling agent. SPI films with bis(tetramethyl)ammonium 2,2'-benzidinedisulfonate ($Me_4N$-BDS)/4,4'-diaminochalcone (DAC)/pyromellitic dianhydride (PA)= 90/10/100 possessed very linear response(Y = -0.04528X+7.69446, $R^2=0.99675$) and showed resistance changing from 4.48 to $2.1k{\Omega}$ between 20 and 95 %RH. The response time for absorption and desorption measurements between 33 and 94 %RH% was about 79 s, which affirmed the high efficiency of crosslinked SPI film for rapid detection of humidity. A negative temperature coefficient showing $-0.49%RH/^{\circ}C$ was found and proper temperature compensation should be considered in future applications. Moreover, pretreatment of the substrates with chalcone-containing silane-coupling agent was performed to improve the water durability and the stability of the humidity sensors at a high humidity and a high temperature and long-term stability for 480 h. The crosslinked SPI films anchored to electrode substrate could be a promising material for the fabrication of efficient humidity sensors with superior characteristics compared to the commercially available sensors.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.29 no.1
• /
• pp.18-26
• /
• 2015

Akebiae Caulis is a galenical originated from Akebia quinata Decaisne species. It is commonly used in the treatment of oposiuria, inflammation, nociceptive and fever. Here, we investigated the effect of Akebiae Caulis extract (ACE) to protect hepatocyte against the malfunction of mitochondria and apoptosis. Arachidonic acid (AA)+iron promoted excessive reactive oxygen species (ROS) production and exerted a deleterious effect on mitochondria. Treatment with ACE protected hepatocytes from AA+iron-induced cytotoxicity, as shown by alterations in the protein levels related with apoptosis such as poly(ADP-ribose) polymerase, pro-caspase 3, Bcl-XL and Bcl-2. Moreover, AA+iron-induced $H_2O_2$ production, GSH depletion and mitochondrial dysfunction were alleviated by ACE pretreatment. As a potential molecular mechanism for the ACE-mediated cytoprotection, phosphorylation of AMP-activated protein kinase (AMPK), a key regulator in determining cell survival or death, was increased by ACE. Moreover, ACE treatment enhanced inactive phosphorylation of glycogen synthase kinase-$3{\beta}$ ($GSK3{\beta}$), downstream substrate kinase of AMPK. More importantly, ACE prevented a decrease in the $GSK3{\beta}$ phosphorylation derived by AA+iron, which might contribute to mitohondiral protection and cell survival. To further identify essential compounds in Akebiae Caulis for the protection of AA+iron-mediated cytotoxicity, we found that betulin in combination with hederagenin protected from AA+iron-induced mitochondrial dysfunction. Betulin+hederagenin treatment also increased inactive phosphorylation of $GSK3{\beta}$ in common with ACE. These results suggest that ACE protected hepatocytes against oxidative stress and mitochondrial dysfunction, which is mediated with inactive $GSK3{\beta}$ phosphorylation downstream of AMPK.

• Microbiology and Biotechnology Letters
• /
• v.49 no.1
• /
• pp.88-94
• /
• 2021

The seaweed, Gracilaria verrucosa (red seaweed) was fermented to produce bioethanol. Optimal thermal acid hydrolysis conditions were determined as 200 mM H₂SO₄ and 10% (w/v) seaweed slurry at 130℃ for 60 min yielding 47.5% of pretreatment efficiency (E_p). After the thermal acid hydrolysis, enzymatic saccharification was carried out with 16 U/ml Viscozyme L, Cellic CTec2 or mixture of Viscozyme L and Cellic CTec2 to G. verrucosa hydrolysates. Enzymatic saccharifications with Viscozyme, Cellic CTec2 or mixture of those yielded 7.3 g/l glucose with efficiency of saccharification, E_s = 34.9%, 11.6 g/l glucose with E_s = 64.4% and the mixture of those 9.6 g/l glucose with E_s = 56.6%, respectively. Therefore, based on the E_s value, Cellic CTec2 was selected for the optimal enzyme for enzymatic saccharification of G. verrucosa hydrolysate. The ethanol productions with non-adapted S. cerevisiae CEN-PK2 (wild type) and S. cerevisiae CEN-PK2 with adaptive evolution to galactose produced 8.5 g/l ethanol with Y_EtOH = 0.19 and 21.5 g/l ethanol with Y_EtOH = 0.50 at 144 h, respectively. From these results, the ethanol production by S. cerevisiae with adaptive evolution showed high concentration of ethanol production using G. verrucosa as a substrate.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.4
• /
• pp.524-531
• /
• 2012

The objective of this study was to investigate the organic solubilization (SCOD) and improvement of methane production for pig slurry by thermal hydrolysis. A sludge cake was pretreated by thermal hydrolysis at different reaction temperatures (200, 220, 250, $270^{\circ}C$). Ultimate methane potential (Bu) was determined at several substrate and inoculum (S/I) ratios (1:9, 3:7, 5:5, 7:3 in volume ratio) by biochemical methane potential (BMP) assay for 73 days. Pig slurry SCOD were obtained with 98.4~98.9% at the reaction temperature of $200{\sim}270^{\circ}C$. Theoretical methane potentials ($B_{th}$) of thermal hydrolysates at the reaction temperature of $200^{\circ}C$, $220^{\circ}C$, $250^{\circ}C$, $270^{\circ}C$ were 0.631, 0.634, 0.705, $0.748Nm^3\;kg^{-1}-VS_{added}$, respectively. $B_u$ of $200^{\circ}C$ thermal hydrolysate were decreased from $0.197Nm^3\;kg^{-1}-VS_{added}$ to $0.111Nm^3\;kg^{-1}-VS_{added}$ with the changes of S/I ratio from 1:9 to 7:3, and also $B_u$ of different thermal hydrolysates ($220^{\circ}C$, $250^{\circ}C$, $270^{\circ}C$) showed same tendency to $B_u$ of $200^{\circ}C$ thermal hydrolysate according to the changes of S/I ratio. Anaerobic biodegradability ($B_u/B_{th}$) of $200^{\circ}C$ thermal hydrolysate at different S/I ratios was decreased from 32.2% for S/I ratio of 1:9 to 17.6% for S/I ratio of 7:3. $B_u/B_{th}$ of $220^{\circ}C$, $250^{\circ}C$, and $270^{\circ}C$ thermal hydrolysat were decreased from 36.4% to 9.6%, from 31.3% to 0.8%, and from 26.6% to 0.8%, respectively, with the S/I ratio change, respectively. In this study, the rise of thermal reaction temperature caused the decrease of anaerobic digestibility and methane production while organic materials of pig slurry were more solubilized.