• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.23-30
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• 2007

The ultimate objective of this study is to develop oxygen-enriched combustion techniques applicable to the system of practical industrial boiler. To this end the combustion characteristics of lab-scale LNG combustor were investigated as a first step using the method of numerical simulation by analyzing the flame characteristics and pollutant emission behaviour as a function of oxygen enrichment level. Several useful conclusions could be drawn based on this study. First of all, the increase of oxygen enrichment level instead of air caused long and thin flame called laminar flame feature. This was in good agreement with experimental results appeared in open literature and explained by the effect of the decrease of turbulent mixing due to the decrease of absolute amount of oxidizer flow rate by the absence of the nitrogen species. Further, as expected, oxygen enrichment increased the flame temperatures to a significant level together with concentrations of $CO_2$ and $H_2O$ species because of the elimination of the heat sink and dilution effects by the presence of $N_2$ inert gas. However, the increased flame temperature with $O_2$ enriched air showed the high possibility of the generation of thermal $NO_x$ if nitrogen species were present. In order to remedy the problem caused by the oxygen-enriched combustion, the appropriate amount of recirculation $CO_2$ gas was desirable to enhance the turbulent mixing and thereby flame stability and further optimum determination of operational conditions were necessary. For example, the adjustment of burner with swirl angle of $30\sim45^{\circ}$ increased the combustion efficiency of LNG fuel and simultaneously dropped the $NO_x$ formation.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.189-193
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• 1993

Exposure of dissociated cultures from fetal rat brainstem to glutamate for upto 6 h decreased cellular contents of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in a concentration- and time-dependent manner. In addition, glutamate induced lactate dehydrogenase leakage. Tetrodotoxin did not block the effects induced by glutamate. MK-801 $(1{\mu}M)$, an N-methyl-D-aspartate (NMDA) channel blocker, but not 6-cyano-2,3-dihydroxy-7-nitro-quinoxazoline $(CNQX;\;3{\mu}M)$, a non-NMDA receptor antagonist, blocked glutamate-induced effects, indicating that these glutamate-induced responses are mediated through NMDA receptors.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.250-255
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• 2004

This study was carried out to investigate the chemical properties of rainwater in the Suwon and Taean areas. Rainwater was collected during the farming seasons of 2002 and 2003. The number of samples collected in Suwon and Taean were 69 and 71, respectively. These were analyzed for chemical composition. The pH of samples collected in April was higher than those collected after June. The most common range of rainwater pH was 5.0-5.6 in Suwon and 4.5-5.0 in Taean during investigation periods. The neutralization capacity of rainwater acidity by $Ca^{2+}$ and N $H_4$$^{+}$ was decreased during the rainy season. The EC of rainwater was lower during the rainy season. Cation concentrations in rainwater were N $H_4$$^{+}$ > $H^{+}$ > $Ca^{2+}$ > $Mg^{2+}$ > $K^{+}$ in Suwon and $Ca^{2+}$ > N $H_4$$^{+}$ > $H^{+}$ > $K^{+}$ > $Mg^{2+}$ in Taean. In the case of anion, the order was sol > N $O_3$$^{[-10]}$ > C $I^{[-10]}$ in Suwon and S $O_4$$^{2-}$ > C $I^{[-10]}$ > N $O_3$$^{[-10]}$ in Taean. The mean values of sulfate in rainwater were 130 $\mu$eq $L^{-1}$ in Suwon and 117 $\mu$eq $L^{-1}$ in Taean. The ratio of non-sea salt sulfate to sulfate (nss-S $O_4$$^{2-}$ > S $O_4$$^{2-}$) was 89% and 88%. This implies that the major origin of sulfate in rainwater might be anthropogenic.ht be anthropogenic..

• Food Science and Preservation
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• v.31 no.3
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• pp.452-461
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• 2024

This study evaluated the in vitro antioxidant activities of ethanolic Polygonum multiflorum (P. multiflorum) extracts and their cytoprotective effects on H₂O₂-induced HT22 and SK-N-MC cells. Among ethanolic extracts of P. multiflorum, the 40% ethanolic extract of P. multiflorum exhibited high total phenolics and flavonoid contents, with 105.68 mg of GAE/g and 28.92 mg of RE/g, respectively. The 40% ethanolic extract of P. multiflorum showed a high 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity and malondialdehyde (MDA) inhibitory effect. The 40% ethanolic extract of P. multiflorum also showed efficient inhibitory activity against α-glucosidase and acetylcholinesterase. Moreover, the 40% ethanolic extract of P. multiflorum reduced oxidative stress and increased cell viability in H₂O₂-induced HT22 and SK-N-MC cells as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zoliumbromide (MTT) and 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA) assay. High-performance liquid chromatography (HPLC) identified 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG) as the bioactive compound in the 40% ethanolic extract of P. multiflorum.

• Journal of Aquaculture
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• v.16 no.1
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• pp.1-7
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• 2003

A new technique combining forced-feeding and dorsal aorta cannulation was developed to monitor concentration of nutritions in the blood circulation and their metabolites in rainbow trout. To study the effect of dorsal aorta cannulation on stress, 30 rainbow trout (523$\pm$5.4 g; Mean$\pm$SD) were divided into 6 groups of 5 individuals each. A group was anesthetized and blood samples were taken at 0, 3, 6, 12, 24 or 48 h after dorsal aorta cannulation. Hematocrit peaked at 6 h and returned to 0 values by 12 h after dorsal aorta cannulation. Plasma cortisol and glucose concentrations also peaked at 6 h and returned to 0 values by 48 h after dorsal aorta cannulation. Based on the plasma cortisol and glucose concentrations, the rainbow trout recovered from the operation of dorsal aorta cannulation within 48 h. To compare the patterns of plasma free amino acid concentrations after force-feeding in the fish with dorsal aorta cannulation, 5 dorsal aorta cannulated individuals (511$\pm$6.2 g) were kept in a cage. After 48 h starvation, they were anesthetized and blood samples were taken at 0, 4, 8, 12, 24, 36 or 48 h after forced-feeding. The concentration of all plasma free amino acids, except isoleucine, leucine, phenylalanine, and tryptophan, also peaked at 4 h and returned to 0 values by 24 h after feeding. The combined technique allows forced-feeding and repeated sampling of blood in rainbow trout with minimum stress.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1994.07a
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• pp.7-8
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• 1994

한국산 표고버섯 균사체를 액체배양하여 천연항암물질로 알려진 단백다당체를 추출한 후 그 물질의 특성에 대하여 검토하였다. 균사체의 최적 재양조건을 TGY배지로 조사한 바 온도 $25^{\circ}C$, 배양초기 pH4.0, 교반속도 300rpm, 균사배지 접종량을 10.0%로 하고 산소 통기량을 1.0volume of ait/volume of medium/mimute으로 하였을때 가장 양호한 조건이였으며, 대량생산 하기 위한 SCM배지에서 최적의 C/N비는 13.1오써 7일간 배양하였을때 18.8g/L의 균사령을 얻었으며, 이때 생산수율은 0.46으로 나타났다. 발효가 끝난 배양액에서 균사, 여액 그리고 배양액의 전체에서 단백다당체를 분리한 결과 각 분획에서 단백다당체가 각각 0.55%, 0.12%, 0.69%가 회수되어 배양액 전체에서 단백다당체를 추출하는 것이 바람직하며, 추출방법으로 열수추출, glass bead추출 및 cellulasa처리를 하여 단백다당체의 수율을 비교한 결과 0.25-0.5mm glass nead로 30분간 균사체를 분쇄한 다음 열수추출을 1시간을 하였을때 990mg/100ml의 단백다당체를 얻을 수 있었다. 고단백다당체를 1차 단백질 가수분해 효소로 분해하고, EDAE cellulose 및 Sepadex G-100 column chromatography로 정제한 후, TLC/FLD, ultracentrifugation한 결과 순수한 물질임을 알 수 있었다. 단백다당체의 항암효과 조사중 in vitro배양에서 $P_{388}$과 $L_{1210}$에 대한 단백다당체의 활성단위 1 unit는 1mg정도였으며, 인체의 장암세포인 HCT-48, HRT-18, HT-29 밀 간암세포인 Hep G2 대한 생육저해 단위는 각각 4.4, 3.6, 6.6, 2.6mg이었다. HCT-48과 Hep G2 세포의 크기 분포도는 대조군에 비하여 시간이 경과함에 따라, 그리고 단백다당체의 농도가 증가함에 따라 peak가 작은 size 쪽으로 이동하였다. 또, 단백다당체를 첨가 배양한 HCT-48과 Hep G2세포의 현미경 관찰에서 본래의 암세포 형태가 변형되고 크기가 감소하며 세포사이의 경계막이 흐트러지면서 세포수가 감소하고 사멸하였다. In vivo실험에서는 대조군보다 단백다당체를 첨가한 군에서 항체 형성능력이 대조군에 비하여 형질세포가 2배로 증가하였다. 단백다당체의 화학적 성분 분석에서 다당함량은 46.1%이면 구성다당류는 glucose, galactose, mannose, xylose로 구성되었고 단백질의 함량은 7.28%이며, 구성아미노산은 15종의 아미노산으로 되었다. 또 무기물은 Na, K, Zn, Ca등의 순으로 이루어 짐을 알 수 있었다.

• Journal of Life Science
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• v.31 no.6
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• pp.559-567
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• 2021

This study compared the nutritional characteristics and antioxidant effects of sea mustards sourced from five different areas (Barammaegi, Gultongmeori, Chanmulgae, Johongtaek, and Goraedeung) in Taejongdae, Youngdo, Busan. The contents of total flavonoids and phenols and fatty acid composition were measured. To evaluate their antioxidant effects, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays were used. Acetone/methylene chloride (A+M) extracts from all the sea mustards contained higher amounts of total flavonoids and phenols than methanol (MeOH) extracts. Among the sea mustards obtained from the different areas, the total flavonoid and total phenolic content of the A+M extract of the sea mustard from Gultongmeori was 1.44±0.04 mg/g and 1.72±0.06 mg/g, respectively. In terms of the fatty acid composition, the Gultongmeori sea mustard had higher percentages of total n-6, total n-3, eicosapentaenoic acid (EPA, 20:5n-3), and docosahexaenoic acid (DHA, 22:6n-3) than the sea mustards from the other areas. The A+M extract of the sea mustard from Gultongmeori was more effective in terms of scavenging free radicals as compared with that of the other sea mustards, as assessed by the DPPH and ABTS assays (p<0.05). In a 120-minute reactive oxygen species (ROS) production assay, all the extracts tested decreased cellular ROS production induced by H₂O₂ compared to that produced by exposure to an extract-free control (p<0.05). The extracts from Barammaegi and Gultongmeori had a greater inhibitory effect on cellular ROS production. These results indicated that the antioxidant effects of sea mustards might be associated with a higher amount of flavonoids and phenols. This study suggests that food-processed products from sea mustard can be developed as functional foods for promoting health in the local population.

• Journal of Life Science
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• v.28 no.7
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• pp.841-848
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• 2018

The flavonoid content and antioxidant effects of extracts from Stachys sieboldii Miq. and Lycopus lucidus Turcz were compared. The flavonoid content of the acetone + methylene chloride (A+M) extract of L. lucidus Turcz was 233.2 mg/g, suggesting that the extract was greater than that of S. sieboldii Miq. In the DPPH assay and the A+M and methanol (MeOH) extracts from L. lucidus Turcz had greater scavenging effects than those of S. sieboldii Miq. (p<0.05). The A+M extract from L. lucidus Turcz (0.5 mg/ml concentration) had an 82% scavenging effect in the DPPH assay. In the ABTS assay, A+M extracts from both S. sieboldii Miq. and L. lucidus Turcz (0.5 mg/ml concentration) had scavenging effects of 90% and 88%, respectively (p<0.05), suggesting that both A+M extracts had greater scavenging effects than those of both MeOH extracts. In a 120 min ROS production assay, all tested extracts dose-dependently decreased the cellular ROS production that was induced by $H_2O_2$, as compared to those produced by exposure to the extract-free control. The A+M extracts from both S. sieboldii Miq. and L. lucidus Turcz had greater inhibitory effects on cellular ROS production than those of both MeOH extracts at all concentrations tested. Treatment with the A+M extracts from S. sieboldii Miq. and L. lucidus Turcz (0.25 mg/ml concentration) inhibited the cellular ROS production by 60% and 86%, respectively. These results suggest that the A+M extracts of Stachys sieboldii Miq. and L. lucidus Turcz inhibit cellular oxidation and may contain valuable bioactive compounds, such as flavonoids.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.227-232
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• 2006

Styela clava (also called as rough sea squirt or leathery tunicate) is regarded as native to the northwest Pacific region including Korea and widely distributed in parts of northwestern Europe, North America and Australia. To evaluate Styela clava as a potential bioactive agent, the antioxidant activity of aceton extracts from Styela clava (whole, substance and tunic) was tested by measuring inhibitory effect of $H_2O_2$ induced DNA damage using comet assay. Also, anticancer activity on human colon cancer cell (HT-29) was investigated by MTT reduction assay. The $200\;{\mu}M$ $H_2O_2$ induced DNA damage was inhibited with Styela clava aceton extract in dose dependent manner in human leukocytes. The maximum inhibition was by 62.8, 62.1 and 78.3% at the concentration of $50\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. The aceton extracts from S. clava were also found to inhibit the growth of human colon cancer cell. The cell proliferation rates decreased to 26.9, 30.6 and 12.0% at the concentration of $500\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. These results support that aceton extracts from S. clava may be a potential candidate as a possible antimutagenic and chemotherapeutic agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1304-1308
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• 2006

The present study describes the preliminary evaluation of the antioxidant activity and the cytotoxic effect of Ceramium kondoi. The antioxidant activities and cytotoxic effect of the water extracts were evaluated by total phenolic contents (TPC), DPPH radical scavenging activity (RSA), reducing power (RP), comet assay, and MTT reduction assay. TPC, DPPH RSA, and RP of the extract at the concentration of $1,000{\mu}g/mL$ was $659.2{\mu}M$, 86.0%, and 1.084, respectively, and those were concentration dependent. The $200{\mu}M\;H_2O_2-induced$DNA damage was inhibited by C. kondoi water extract in a dose dependent manner in human leukocytes. The inhibition was by 62.3, 39.8, 24.8% and 16.4% at the concentration of 5, 10, $25{\mu}g/mL$ and $50{\mu}g/mL$, respectively. Cytotoxic activity on HT-29 cells and MCF-7 cells of the C. kondoi water extract at the concentration of $10{\mu}g/mL$ was 49% and 60%, respectively. These results strongly support the possibility of C. kondoi as a source of natural functional materials.