• 한국결정성장학회지
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• 제13권2호
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• pp.73-78
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• 2003

Tetraethyl orthosilicate (TEOS)로부터 유도된 동결건조 실리카 젤의 기공구조에 미치는 하소온도의 영향이 질소 등온흡착 및 수은압입법에 의하여 조사되었다. 동결건조물은 다소간의 마이크로기공을 함유하고 있었으나 주로 4~6nm 크기의 매크로기공 및 7~20$\mu\textrm{m}$ 크기의 매크로기공으로 구성되어 있었다. 하소온도의 증가에 따른 기공구조변화는 치밀화 정도에 의존하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권2호
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• pp.150-155
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• 2001

It has been observed that water, which is absolutely essential for enzyme activity, can induce the agglomeration of enzyme particles in organic media. Although enzyme agglomeration is significant in that it usually reduces enzyme activity and stability, little attention has been paid to the quantitative analysis of enzyme agglomeration behavior in nonaqueous biocatalytic systems. In this study, the effect of water and silica gel on enzyme agglomeration were investigated using Candida rugosa lipase and cyclohexane as a model enzyme and an organic medium. The extent of enzyme agglomeration was quantified by sieve analysis of freeze-dried agglomerates. Increasing the water content of the medium increased the size of the enzyme agglomerates, and it was found that water produced during the esterification reaction could also promote the agglomeration of enzyme particles suspended in organic media. On the other hand, the size of the enzyme agglomerates was remarkably reduced in the presence of silica gel at the same water content. We also show that this increase in the size of enzyme agglomerates results in lower reaction rates in organic solvents.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2002년도 제9차 국제심포지움 및 추계정기학술발표회
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• pp.53-53
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• 2002

Shoot tips of in vitro propagated plantlets were cryopreserved using encapsulation/dehydration procedures. Shoot tips were excised under filter sterilized antioxidants solution (0.2M phosphate buffer, pH 5.7 supplemented with 5g/1 ascorbic acid and 15g/1 sodium borate). They were drawn up into a sterile 10 $\textrm{cm}^3$disposable pipette and were dropped into the culture medium with 2.5w/v Na-alginate, then into 100mM CaCl$_2$.2$H_2O$. Encapsulated shoot tips were transferred into 10㎤ of liquid culture medium with a range of sucrose concentrations (0.25-1.0M) and were incubated in dark for 24 hours in 18C at 40rpm. Beads were then dehydrated in silica gel for different time intervals (1-24 hours). Then they were freeze dried either rapidly (plunge directly into liquid N2 or in two stages (samples were kept at 20C for 10 minutes, then reduced to 35C at 1C per minute. Then, plunge into liquid $N_2$). The influence of sucrose and silica gel pre-treatment on pre- and post-freeze shoot growth was examined.(중략)

• 생약학회지
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• 제45권2호
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• pp.93-100
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• 2014

The Acer tegmentosum (3 kg) were extracted with boiled water and the freeze dried extract powder was partitioned with $CH_2Cl_2$, EtOAc, n-BuOH and $H_2O$, successively. From the EtOAc and n-BuOH fraction, six phenolic compounds were isolated through the silica gel, octadecyl silica gel and sephadex LH-20 column chromatography. On the basis of spectroscopic methods, such as $^1H$-NMR and $^{13}C$-NMR, and LC/MS, the chemical structures of the compounds as feniculin (1), avicularin (2), (+)-catechin (3), (-)-epicatechin (4), salidroside (5) and 6'-O-galloylsalidroside (6). In this study, compounds 1 and 2 have been first isolated from the A. tegmentosum. To provide insight into the effects of six compounds isolated from A. tegmentosum on inflammation, we investigated its effect on nitric oxide (NO) production in RAW 264.7 cells using lipopolysaccharide (LPS) stimulation. Compounds 1 and 6 slightly repressed NO production. Also, compounds 3 and 4 inhibited NO secretion with statistical significance. However, compounds 2 and 5 did not show any inhibitory effect on NO production.

• 한국산림과학회지
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• 제100권2호
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• pp.136-141
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• 2011

본 연구는 산돌배나무 잎에서 추출한 분획물의 항암 및 항균효과를 조사하여 화장품소재로 적용 가능성을 확인하기 위하여 수행하였다. 산돌배나무 잎을 채취하여 건조시킨 후 분쇄하여 60% acetone-$H_{2}O$(6:4, v/v)로 추출하고 아세톤 가용부를 분획하여 동결건조 시켰다. 아세톤 및 물 가용부를 Sephadex LH-20으로 충진한 칼럼에서 MeOH을 용출용매로 사용하여 칼럼크로마토그래피를 실시하고 또한 MeOH를 전개용매로 사용한 MIC-gel을 이용했다. 단리된 화합물들은 silica-gel TLC로 확인하였다. 항암효과는 마우스 피부암 세포(B16F10)를 이용한 MTT assay로 측정했다. 산돌배나무 잎으로부터 얻어진 분획물의 암세포 생장 저해율은 80% 이상의 저해률을 보였다. 항균활성 실험에서 산돌배나무 잎의 분획물은 그람양성균인 Staphylococcus aureus, Staphylococcus epidermidis에 대하여 0.25 mg/disc에서 1.3 cm, 2 cm의 생육 저해환을 나타내었다. 그람음성균인 Escherichia coli 에 대하여 0.5 mg/disc에서 각 분획물들은 1.1 cm~1.5 cm의 생육 저해환을 나타내었다. 이상의 결과로 미루어 보아 산돌배나무 잎의 아세톤 분획물은 항암 및 항균효과를 가진 천연소재임을 확인할 수 있었다.

• 한국산림과학회지
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• 제99권6호
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• pp.885-890
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• 2010

본 연구는 산돌배나무(Pyrus ussuriensis) 잎에서 추출한 분획물의 항산화능을 조사하여 화장품소재로 적용 가능성을 확인하기 위하여 수행하였다. 산돌배나무 잎을 채취하여 건조시킨 후 분쇄하여 60% acetone-$H_2O$(6:4, v/v)로 추출하고, 아세톤 가용부를 분획하여 동결건조 시켰다. 아세톤 및 물 가용부를 Sephadex LH-20으로 충진한 칼럼에서 메탄올 MeOH을 용출용매로 사용하여 칼럼크로마토그래피를 실시하고 또한 MeOH를 전개용매로 사용한 MICgel을 이용했다. 단리된 화합물들은 Silica-gel TLC로 확인하였다. 폴리페놀 함량은 산돌배나무 잎의 아세톤 분획물에서 914 mg/g으로 정량되어 높은 함량이었다. 산돌배나무 잎의 아세톤 분획물을 이용하여 항산화효과를 분석하여 얻은 결론을 요약하면 다음과 같다. 전자공여능의 경우 산돌배나무 잎의 아세톤 분획물의 100 ppm농도에서 80%이상의 전자공여능을 나타내었다. 산돌배나무 잎의 아세톤 분획물 중 한 분획물의 Superoxide dismutase(SOD) 유사활성은 1000 ppm에서 77%의 활성을 보였다. 분획물의 Xanthine oxidase 저해능은 10 ppm에서 38%의 저해률을 보였다. 이상의 결과로 미루어 보아 산돌배나무 잎의 아세톤 분획물은 항산화효과를 가진 천연소재임을 확인할 수 있었다.

• 대한화학회지
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• 제42권1호
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• pp.51-56
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• 1998

남조류 독성물질인 Microcystins은 자연계에 매우 미량 존재하기 때문에 이를 분리 및 정제하기가 쉽지 않다. 본 연구에서는 자연계에 존재하는 남조류 동결건조시료로부터 Microcystin RR과 LR을 분리 및 정제하는 새로운 방법을 개발하였다. 약 7.5g의 실리카겔을 정지상으로 사용하고 혼합용액인 ethyl acetate: iso-propanol:water(30: 45: 25)을 이동상으로 사용하는 open column system으로 시료를 전개한후 용액을 3mL간격으로 받아냈다. 받아낸 용액중의 Microcystin RR과 LR은 TLC와 HPLC(high performance Liquid Chromatography)를 이용하여 확인한 후 농축, 정제하였다.

• 한국환경과학회지
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• 제14권4호
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• pp.413-425
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• 2005

The 16 priority PAHs (Polycyclic Aromatic Hydrocarbons) designated by US Environmental Protection Agency were analyzed for some digested sludges from wastewater treatment plants in Korea. PAHs are an important group of organic contaminants present in sewage sludge due to their persistence and toxic potential. PAHs were extracted from freeze-dried sludges using a methylene chloride-methanol (2:1) mixture in a soxhlet extractor. The extracts were cleaned-up by silica gel/alumina combination column and subsequently fed into gas chromatograph/mass spectrometer (GC/MS) for determining PAH contents. The sum of the 16 PAHs in the sewage sludge varied from 534.8 to $5754.5 {\cal}ug/{\cal}kg$, dry wt.. In the sewage sludge, phenanthrene appears as the most abundant PAHs, followed by naphthalene, pyrene, fluoranthene. Source of the investigated sewage sludges relatively predominated pyrogenic. PAHs levels of sewage sludges in Korea appeared to be lower than those in other countries.

• Journal of the Korean Wood Science and Technology
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• 제49권3호
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• pp.267-273
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• 2021

Camellia nut shell was collected, dried at room temperature and ground to get fine powder. The powder was extracted three times with 95% EtOH, combined, evaporated, and then freeze dried. The crude powder was dissolved in H₂O and then sequentially fractionated with n-hexane, CH₂Cl₂, EtOAc and n-BuOH. A part of EtOAc fraction was chromatographed on a silica gel and on a Sephadex LH-20 columns using MeOH, aqueous MeOH, EtOAc-n-hexane and EtOH-n-hexane to isolate gallotannins. Three gallotannins, 1,2-di-O-galloyl-β-D-glucopyranoside (2), 1,2,6-tri-O-galloyl-β-D-glucopyranoside (3) and 1,2,3,6-tetra-O-galloyl-β-D-glucopyranoside (4), including gallic acid (1), were isolated and elucidated by NMR and Mass spectroscopies. Although nothing new, these gallotannins were first reported from the nut shell extractives of camellia tree (Camellia oleifera C. Abel). This study was to investigate the chemical constituents, especially hydrolysable tannins, of nut shell extractives of Camellia oleifera and to provide basic information for the future chemical utilization of this species.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.85-88
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• 2003

Polycyclic aromatic hydrocarbons (PARs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRT AP) of Europe. A method of the gas chromatographic-mass spectrometric (GC-MS) determination of PARs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PARs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PARs sewage sludge samples varied from 2.44 to 4.82 ${\mu}g$/g. Concentration of emission carcinogen PARs(PARcarc), such as Benzo(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenzo(a, h)anthracene and Indeno(1, 2, 3-cd)pyrene ranged from 0.62 to 1.03 ${\mu}g$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PARs and $\sum$PAHcarc from sewage treatment plants had several pathway each by-products. In the ocean dumping, PAHs and $\sum$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year. In recycle, PAHs and $\sum$PAHcarc emissions were 98.36 kg/year and 428.87 kg/year. In the landfill, PAHs and $\sum$PAHcarc emissions were 190.40 kg/year and 830.21 kg/year. In the incineration, PAHs and $\sum$PAHcarc emission were 33.10 kg/year and 830.21 kg/year. (In case of incineration, the whole provisions of PARs and $\sum$PAHcarc contained to flowed in sludge was supposed to be exhausted to environment through exhaust after incineration.)