• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.558-567
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• 1989

The synthesis of methanol from carbon dioxide and hydrogen was studied for various compositions of Cu/ZnO catalyst system. Effect of the composition ratio of CuO and ZnO on the catalytic activity in the above reaction and the relationship between the activity and the characteristics of the catalysts were explained from the result of surface area measurements, SEM, XRD, and XPS. The major products of the reaction were methanol and carbon monoxide. The selectivity to methanol increased with increase of the copper oxide content in the catalyst up to CuO: ZnO = 30:70 weight ratio, and decreased rapidly when the content is above 70%. SEM and BET measurements, indicate that this point corresponds to the increasing point of the catalyst crystallite size and the decreasing point of the surface area. As to the Cu/Cu + Zn atomic ratio, the surface concentration of copper measured by XPS decreased remarkably when the copper oxide content in catalyst was higher than 50%. All the unreduced catalysts had almost same binding energy of Cu(2P3) level, but the binding energy for $Cu(2P^3)$ level of reduced catalysts was lowered than that of calcined catalysts. The surface copper species which was in the maximum amount when the CuO:ZnO composition in the catalyst was 30:70, existed as zero valent copper. This result agreed with the experimental result that the highest rate of methanol formation was observed when the CuO content in the catalyst was 30%. It was postulated that these reduced catalysts performed with a relatively strong basicity because the formation rate of acetone was higher than that of propylene in isopropanol decomposition as measured in a pulse type reactor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1271-1278
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• 2007

In this study, the ability of Styela clava or Styela plicata to reduce ethanol-induced hepatotoxicity and hepatic and leucocytic DNA damages was evaluated. Twenty four male SD rats were given 25% ethanol containing water (ad lib, p.o.) and divided into 3 groups; ethanol treated control group (EtOH), ethano1+3% S. clava (EtOH+SC), and ethano1+3% S. plicata (EtOH+SP). After 6 weeks, the supplementation of S. clava reduced the plasma ALT, ALP and LDH activities significantly (p<0.05), while S. plicata induced significant decrease in the plasma LDH activity only. The comet assay was employed to quantify the alcohol-induced DNA damage in rat hepatocytes and leucocytes. A significant protective effect on hepatic and leucocytic DNA damages was observed in S. clava or S. plicata supplemented groups compared to the EtOH control group. The hepatic DNA damage was correlated positively with plasma ALP and LDH activities. These results demonstrated that S. clava or S. plicata supplementation protected alcohol-induced hepatic and leucocytic DNA damage.

• Korean Journal of Crystallography
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• v.6 no.1
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• pp.1-13
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• 1995

Cr:A12O3 and Ti:A12O3 single crystals were grown by Czochralski method, and the effects of crystal growth parameters such as pulling rate, rotation rate, dopant and growth atmosphere on crystal quality were investigated. And spectroscopic properties including lasing efficiency were also measured. Single crystals, sized of 20mm in diameter and 100-135mm in length, were successfully grown from the seed of <001> direction. With the doping level of 0.5w/o Cr2O3, pulling rate 2.0mm/hr, rotation rate of 30rpm and inert atmosphere by nitrogen gas, high quality crystals of Cr:A12O3 were grown. While in case of Ti:A12O3 crystals, high quality crystals were grown under the conditions of the doping level of 0.25w/o TiO2, pulling rate of 1.5mm/hr, rotation rate of 30rpm and reducing atmosphere by hydrogen - nitrogen mixed gas. It was confirmed that Cr3+ ion which maintains its ionoc valence during growth easily de-bubbled than Ti4+ ion which changes its valence, Fe3+ ion also has do-bubbling effect to Ti:A12O3 crystal and the reducing atmosphere by 90% N2 - 10% H2 mixed gas gave effective result on the changing of Ti4+ to Ti3+ and de-bubbling. As a result of spectroscopic measurements of Cr:A12O3 crystal, 4A2 →4F2 and 4F1 absorption transitions and E →4A2(R1) and 2A →4A2(R2) fluorenscence transitions were confirmed. And it was measured that wavelengths of laser R1 and R2 transitions were 696±5nm and 692±5nm respectively, line width of these transitions were 12A, and life-time of fluorenscence was 152μsec. In case of Ti:A12O3 crystals, it was confirmed that absortion transition of 4T2→4E and fluorescence transition of 4E→4T2 with wide range of 650-1050nm was occured. And 147μsec of life-time of fluorescence, 125.4 of figure of merit and 9% of laser efficience were also measured.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.522-534
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• 1995

Background: In the pathogenesis of acute lung injury induced by lipopolysaccharide(LPS), oxygen radiclls are known to be involved in one part. Superoxide dismutase(SOD) protects oxygen radical-induced tissue damage by dismutating superoxide to hydrogen peroxide. In eukaryotic cells, two forms of SOD exist intracellularly as a cytosolic, dimeric copper/zinc-containing SOD(CuZnSOD) and a mitochondrial, tetrameric manganese-containing SOD(MnSOD). But there has been little information about SOD gene expression and its regulation in pulmonary alveolar macrophages(PAMs). The objective of this study is to evaluate the SOD gene expression induced by LPS and its regulation in PAMs of rat. Method: In Sprague-Dawley rats, PAMs obtained by broncholaveolar lavage were purified by adherence to plastic plate. To study the effect of LPS on the SOD gene expression of PAMs, they were stimulated with different doses of LPS($0.01{\mu}g/ml{\sim}10{\mu}g/ml$) and for different intervals(0, 2, 4, 8, 24hrs). Also for evaluating the level of SOD gene regulation actinomycin D(AD) or cycloheximide(CHX) were added respectively. To assess whether LPS altered SOD mRNA stability, the rate of mRNA decay was determined in control group and LPS-treated group. Total cellular RNA extraction by guanidinium thiocyanate/phenolfchlorofonn method and Northern blot analysis by using a $^{32}P$-labelled rat MnSOD and CuZnSOD cDNAs were performed. Results: The expression of mRNA in MnSOD increased dose-dependently, but not in CuZnSOD. MnSOD mRNA expression peaked at 8 hours after LPS treatment. Upregulation of MnSOD mRNA expression induced by LPS was suppressed by adding AD or CHX respectively. MnSOD mRNA stability was not altered by LPS. Conclusion: These findings show that PAMs of rat could be an important source of SOD in response to LPS, and suggest that their MnSOD mRNA expression may be regulated transcriptionally and require de novo protein synthesis without affecting mRNA stability.

• Food Science and Preservation
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• v.23 no.7
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• pp.995-1003
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• 2016

Ulmus pumila L. bark underwent distilled water extraction under three temperature condition ($4^{\circ}C$, room temperature, or $80^{\circ}C$) and two extraction times (1, or 5 min) in order to develop a functional beverage products. Changes in yield, pH, color, total phenolic (TP) content, tannin content and antioxidant activity of the aqueous extracts were evaluated for each extraction temperature and duration. Extraction conditions did not affect yield or pH value of the extracts; however CIE $b^*$ values were high in extracts prepared under high extraction temperature ($80^{\circ}C$) and long extraction duration (5 min) conditions. Both extraction temperature and duration affected the TP and tannin contents of the extracts; however, all extraction conditions resulted in ${\geq}450\;mg\;GAE/g$ TP content and ${\geq}80\;mg\;CE/g$ tannin content. All extracts exhibited ABTS and DPPH radical scavenging ability similar to that of vitamin C. Nitric oxide inhibition activity was lower in the 5 min duration sample than in the 1 min sample. The $4^{\circ}C$ extraction temperature produced an extract with the highest reducing power and hydrogen peroxide values. Extraction temperature also affected sensory evaluation results with the $80^{\circ}C$ extraction temperature producing significantly higher flavor, bitterness, and color score, than those obtained under $4^{\circ}C$ and room temperature extraction conditions.

• Journal of Embryo Transfer
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• v.30 no.1
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• pp.7-15
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• 2015

The objective of this study was to investigate the efficiency of nicotinic acid on sperm cryosurvival and fertilization ability in frozen-thawed boar semen. Boar semen was collected by glove-hand method and was frozen using freezing solution treated to 0, 5, 10 and 20 mM of nicotinic acid. The frozen sperm for sperm characteristic analysis was thawed such as viability, acrosome reaction, and mitochondrial integrity. The frozen-thawed sperm was estimated by SYBR14/PI double staining for viability, FITC-PNA/PI double staining for acrosome reaction and Rhodamine123/PI double staining for mitochondrial integrity using a flow cytometry. The embryo was estimated in vitro development and DCFDA staining for reactive oxygen species assessment. As results, frozen-thawed sperm viability was significantly higher in 5 and 10 mM ($61.1{\pm}1.5%$,$64.7{\pm}2.0%$) of nicotinic acid than other groups (0 mM, $52.1{\pm}2.3%$; 20 mM, $47.8{\pm}5.1%$, P<0.05). The live sperm with acrosome reaction was significantly higher in 5 and 10 mM of nicotinic acid ($26.1{\pm}1.8%$, $24.9{\pm}1.5%$) than other groups (0 mM, $35.3{\pm}0.8%$; 20 mM, $36.5{\pm}1.9%$, P<0.05). The live sperm with mitochondrial integrity was significantly higher in 5 and 10 mM ($84.2{\pm}3.6%$, $88.4{\pm}2.3%$) of nicotinic acid than other groups (0 mM, $77.3{\pm}4.4%$; 20 mM, $73.3{\pm}3.6%$, P<0.05). Blastocyst rate of in vitro development was significantly higher in 10 mM ($17.0{\pm}1.3%$) of nicotinic acid than other groups (0 mM, $9.4{\pm}0.5%$; 5mM, $12.6{\pm}0.8%$; 20 mM, $5.0{\pm}1.0%$, P<0.05). Moreover, total cell number was higher in 5 and 10 mM ($53.6{\pm}2.9%$, $57.9{\pm}2.8%$) of nicotinic acid than other groups (0 mM, $41.0{\pm}1.4%$; 20 mM, $23.2{\pm}2.8%$, P<0.05). Hydrogen peroxide in embryos was lower in 5 mM nicotinic acid ($0.7{\pm}0.1%$) than other groups (0 mM, $1.0{\pm}0.1%$; 10mM, $0.9{\pm}0.0%$; 20 mM, $1.4{\pm}1.0%$, P<0.05). In conclusion, nicotinic acid-treated semen improves cryosurvival and quality of spermatozoa. Also, the fertilized oocytes with nicotinic acid improve quality of embryo and blastocyst formation.

• Journal of the Korean Wood Science and Technology
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• v.9 no.3
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• pp.7-15
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• 1981

A Japanese larch has been reforested very much in Korea, but it is not used as a wood resources for paper pulp by now. So this study is carried out to utilize the larchwood for paper pulp manufacture through the Asplund pulping process. The experiment on increasing in the brightness of the pulp is made through the addition of $MgSO_4$, $ZnSO_4$, $Al_2(SO_4)_3$, and KI as a cellulose stabilizer in chip treatment with caustic soda which is followed by high-temperature defibration and conventional peroxide bleaching (5% NaOH plus 2% additive salt per wood in cold pretreatment), or in high-consistency (30%) pulp bleaching of hydrogen peroxide and peracetic acid (100% acitve oxygen per lignin) for conventional one. The results obtained are as follows: 1. The solution of 0.5% additive salts had different pH by the sort of bases that was pH 5.7 in $MgSO_4$, liquor, pH 4.9 for $ZnSO_4$, and pH 2.9 for $Al_2(SO_4)_3$, and in the precepitation of bases which ranged to pH 6-13 for $MgSO_4$, pH 5-12 for $ZnSO_4$, and pH 3-10 for $Al_2(SO_4)_3$. 2. The cellulose stabilizer affective in high-consistency peroxide bleaching was KI, $MgSO_4$, and $ZnSO_4$, but has made a little improvement in de lignification and brightness of pulp in comparison with no addition. 3. The higher alkalinity in the chip treatment has made the higher strength and brightness of larchwood Aspiund pulp instead of downing the pulp yield. And the effective compound for cellulose stabilizer in caustic soda pretreatment of chip was $ZnSO_4$, $Al_2(SO_4)_3$ and KI in order for the conventional peroxide bleaching after Asplund pulping. 4. Therefore, the more effective additives for cellulose stabilization in high-temperature defibration of larchwood suppose to be $ZnSO_4$, $Al_2(SO_4)_3$, and KI, while KI and $MgSO_4$ for peroxide bleaching.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1139-1145
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• 2006

In this study, antioxidant activities of enzymatic and methanolic extracts from E. cava stem and leave were evaluated by measuring the scavenging activities on 1,1 diphenyl 2 picrylhydrazyl (DPPH), hydroxyl radical, hydrogen peroxide and the inhibitory effects on DNA damage induced by oxidative stress of cells. Enzymatic extracts were prepared by enzymatic hydrolysis of both stem and leave using food grade five different carbohydrases (Viscozyme, Celluclast, AMG, Termamyl, Ultraflo) and five proteases (Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase). The enzymatic extracts were lower than methanolic extracts in polyphenol contents, but higher in extraction yield by approximately 30%. The enzymatic extracts were superior to methanolic extracts in DPPH and H2O2 scavenging activities and DNA damage protective effect. There were no significant antioxidant activity difference between stem and leave, but the extracts of leave were relatively better than those of stem. In this study it is suggested that E. cava stem as well as its leave would be a good raw materials for antioxidants compound extraction and enzymatic hydrolysis would be a good strategy to prepare antioxidant extracts from seaweeds.

• Clean Technology
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• v.28 no.1
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• pp.24-31
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• 2022

Petroleum-based plastics are used for various purposes and pose a significant threat to the earth's environment and ecosystem. Many efforts have been taken globally in different areas to find alternatives. As part of these efforts, this study manufactured alginate-based polyvinyl alcohol (PVA) blended films by casting from an aqueous solution prepared by mixing 10 wt% petroleum-based PVA with biodegradable, marine biomass-derived alginate. Glutaraldehyde was used as a cross-linking agent, and cardanol, an alkyl phenol-based bio-oil extracted from cashew nut shell, was added in the range of 0.1 to 2.0 wt% to grant antibacterial activity to the films. FTIR and TGA were performed to characterize the manufactured blended films, and the tensile strength, degree of swelling, and antibacterial activity were measured. Results obtained from the FTIR, TGA, and tensile strength test showed that alginate, the main component, was well distributed in the PVA by forming a matrix phase. The brittleness of alginate, a known weakness as a single component, and the low thermal durability of PVA were improved by cross-linking and hydrogen bonding of the functional groups between alginate and PVA. Addition of cardanol to the alginate-based PVA blend significantly improved the antibacterial activity against S. aureus and E. coli. The antibacterial performance was excellent with a death rate of 98% or higher for S. aureus and about 70% for E. coli at a contact time of 60 minutes. The optimal antibacterial activity of the alginate-PVA blended films was found with a cardanol content range between 0.1 to 0.5 wt%. These results show that cardanol-containing alginate-PVA blended films are suitable for use as various antibacterial materials, including as food packaging.

• Journal of Wetlands Research
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• v.24 no.2
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• pp.83-92
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• 2022

The amount of the plastic waste has been increasing according to global demand for plastic. Microplastics are the most hazardous among all plastic pollutants due to their toxicity and unknown physicochemical properties. This study investigates the optimal methodology that can be applied to sewage samples for detecting microplastics before discussing reducing microplastics in MWTPs. In this study, the effect of different pretreatment methods while detecting microplastic analysis of MWTP influent samples was investigated; the samples were collected from the J sewage treatment plant. There are many pretreatment methods but two of them are widely used: Fenton digestion and hydrogen peroxide oxidation. Although there are many pretreatment methods that can be applied to investigate microplastics, the most widely used methods for sewage treatment plant samples are Fenton digestion and H₂O₂ oxidation. For each pretreatment method, there were factors that could cause an error in the measurement. To overcome this, in the case of the Fenton digestion pretreatment, it is recommended to proceed with the analysis by filtration instead of the density separation method. In the case of the H₂O₂ oxidation method, the process of washing with distilled water after the reaction is recommended. As a result of the analysis, the concentration of microplastics was measured to be 2.75ea/L for the sample using the H₂O₂ oxidation method and 3.2ea/L for the sample using the Fenton oxidation method, and most of them were present in the form of fibers. In addition, it is difficult to guarantee the reliability of measurement results from quantitative analysis performed via microscope with eyes. A calibration curve was created for prove the reliability. A total of three calibration curves were drawn, and as a result of analysis of the calibration curves, all R² values were more than 0.9. This ensures high reliability for quantitative analysis. The qualitative analysis could determine the series of microplastics flowing into the MWTP, but could not confirm the chemical composition of each microplastic. This study can be used to confirm the chemical composition of microplastics introduced into MWTP in the future research.