• The Korean Journal of Ceramics
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• 제6권1호
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• pp.74-77
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• 2000

Ta-doped PZT thin films prepared by reactive co-sputtering method could be transformed into single grained perovskite structure utilizing physical etching of Pt bottom electrode. It is found that PZT perovskite phase on damaged (111) Pt electrode by IMD was more easily crystallized than random oriented Pt electrode and less crystallized than (111) Pt electrode. This shows that amorphized Pt electrode surface by IMD process has an effect on crystallization of PZT perovskite phase. 40$\mu\textrm{m}\times40\mu\textrm{m}$ square shape single grain PZT array could be obtained utilizing the difference of incubation time for nucleation of rosettes between ion damaged Pt and (111) oriented Pt electrode. Single grained PZT thin films show low leakage current density of $1\times10^{-7}$ A/$\textrm{cm}^2$ and high break down field of 440kV/cm. The loss of remanent polarization after $10^{11}$ cycles was less than 15% of initial value.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.334-337
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• 2003

This study was carried out to investigate the effect of soil properties, such as soil organic matter(SOM) content and water content on die-off and regrowth of indigenous microbes due to in-situ ozonation. Four different soils were collected and the soil samples applied to different ozonation time(0-360 min) were incubated during 4 weeks. Population of the indigenous microbes was monitored during incubation period. The number of indigenous microbes in all samples dramatically decreased (more than 90%) within 30 minutes of ozone injection. With increased ozonation time by 360 minutes, the number of the indigenous microbes decreased by 99.99% in all samples. Die-off of the indigenous microbes due to ozone treatment was inversely proportional to SOM and water content. Especially, sample 3 and Sample 4 containing relatively high SOM content and water content showed high regrowth rate, and this resulted from the increase of water soluble and biodegradable organic fraction in soil water after ozone treatment. Soil sample ozonated for 360 minutes showed minor increase in microbial population during 4 weeks of incubation period.

• Journal of Chest Surgery
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• 제26권2호
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• pp.80-85
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• 1993

Synthetic and biosynthetic vascular grafts of small diameter have long been considered to be prone to thrombosis, ultimately leading to the complete graft occlusion. Endothelial cell seeding onto synthetic blood-contacting surfaces has been suggested to be an ideal means to solve this problem. This study described a culture method of bovine endothelial cells and evaluated blood-compatibility and seeding efficiency of cultured endothelial cells. Bovine pulmonary artery endothelial cells were harvested enzymatically and grown to confluence on polystyrene culture flask surfaces using established techniques. The identification of endothelial cells was made through the demonstration of expression of factor VIII R:Ag by immunofluorescent technique. To quantitate the effect of improvement in blood-compatibility of viable endothelial cells, endothelial monolayers were exposed to blood containing $\^$111/In-oxine labeled platelets. Viable endothelial monolayers retained less labeled platelets than control surfaces. The Indium-labeled endothelial cells were seeded onto three different blood-contacting surfaces of Dacron vascular graft immobilized in specially equipped wells and incubated for specific time intervals (t=15, 30, 60, 120 minutes). Longer incubation times showed improved cell adherence in collagen-coated and fibrin-coated Dacron vascular graft groups. However in untreated Dacron grafts, no direct relationship was observed between incubation time and endothelial cell seeding efficiency. This may be due to leakage of endothelial cells through porosity of Dacron grafts in this in-vitro experimental condition.

• Asian-Australasian Journal of Animal Sciences
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• 제3권1호
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• pp.1-6
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• 1990

The objective of this experiment was to compare the effect of pH-regulated alkaline hydrogen peroxide (AHP) treatment of rice straw with those of sodium hydroxide (NaOH) and anhydrous ammonia ($NH_3$) treatments on in sacco digestivility. Three non-lactating ruminally cannulated Holstein cows were fed a diet containing 90% forage and 10% concentrate on a dry matter (DM) basis. The AHP treatment significantly (p<0.05) reduced acid detergent lignin content of the straw, resulting in significant (p<0.05) increase of neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose concentrations. Disappearance rates of DM and NDF of the straw significantly (p<0.05) increased at the incubation time of 24 h. On the other hand, those of ADF and cellulose were significantly (p<0.05) higher at the incubation time of 12 h than those of the others. The effective degradability of DM(EDDM), NDF(EDNDF), ADF(EDADF) and cellulose (EDCE) were determined using in sacco nylon bag technique on the basis of 0.05/h solid outflow rate. The greater differences (p<0.05) of EDDM, EDNDF, EDADF and EDCE were found between AHP treated straw and the others. In general, AHP treatment of the straw recorded higher digestion coefficients than untreated straw as well as NaOH and $NH_3$ treated straws. The results of this study demonstrate that AHP treatment can be used as a effective method for improving the nutritive value of rice straw for ruminants.

• Parasites, Hosts and Diseases
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• 제47권1호
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• pp.7-11
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• 2009

Cryptosporidium parvum is a well-known waterborne and opportunistic intracellular protozoan parasite that causes diarrheal illness. In this study, we quantitatively investigated reduction of the infectivity of C. parvum after gamma irradiation and repair of the infectivity during incubation time after irradiation. C. parvum oocysts were subjected to gamma irradiation at various doses (1, 5, 10, and 25 kGy), and the in vitro infectivity was measured by real-time PCR every day up to 7 days after irradiation. The in vitro infectivity of C. parvum on human ileocecal adenocarcinoma cells (HCT-8) was effectively reduced (> $2\;{\log}_{10}$) by irradiation at 10kGy or more. However, in the experiment to find out repair of the infectivity, recovery was not noted until day 7 post-incubation.

• 식물조직배양학회지
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• 제25권5호
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• pp.335-339
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• 1998

미숙배주조직 유래의 배발생캘러스를 이용하여 원형질체의 유리 및 배양에 미치는 요인을 조사하였다. 배발생캘러스로부터 원형질체를 유리시키는데 적당한 배양시간은 16시간이었고, 건전한 원형질체를 유리하는데 적당한 효소용액의 농도는 0.7M $\textrm{BH}_{3}$ 용액과 cellulase 1.0%, macerozyme 1.0%, pctolyase 0.2%가 혼합된 효소용액을 동량으로 조합하였을 때가 가장 효과적이었다. 유리된 원형질체는 MT기본배지에 0.1 mg/L 2,4-D를 첨가한 배지로 배양하면 캘러스 형성이 양호하였다. 유도된 캘러스는 고체배지에 계대배양하고 있으나 생육이 징약한 상태이다. 본 실험결과 배발생캘러스유래의 원형질체와 엽육세포유래의 원형질체 융합에 의한 배양도 가능할 것으로 생각되었다.

• 생명과학회지
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• 제6권2호
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• pp.111-119
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• 1996

The production of interleukin-1(IL-1)and nitric oxide(NO) by cultured fibroblast cells of human nasal turbinate was revealed by biological assay respectively. The cells were incubated for various periods of time in the presence of staphyloccocal toxic shock syndrome toxin-1(TSST-1) and house dust mite(Dermatophagoides farinae, HDM), and the culture supernatants were harvested. There was a little difference in the activities of IL-1beta and the amount of NO produced by the cells when stimulated with 0.002-0.1$\mu$g/ml of TSSTO-1 and 0.02-1$\mu$g/ml of HDM. The shapes of the time course curves for the production of IL-1beta and NO by the cells were different. Groups stimulated with TSST-1 or HDM produced more IL-beta in 2 h than no exposure group(Control). A certain mixed group(TSST-1, 10ng+mite, 100 ng) continued to produce IL-1beta highly throughout the entire incubation period. The cells stimulated with TSST-1 or HDM produced more NO in 2 h and 6 h than that produced in the end of incubation(48 h). Also, the mixed groups were generally similar. There results suggest that induction of IL-1beta by a certain mixed condition(TSST-1+mite) in fibroblast cell in vivo may play a role in inflammation.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.95-98
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• 2007

Polyethylenimine (PEI) has been widely investigated for delivery of DNA into cells. It was previously reported that there were at least two types of cytotoxicity in PEI-mediated gene delivery, immediate and delayed toxicities. PEI-mediated gene delivery protocols use net cationic complexes with an excess of PEI to maintain equilibrium between the complexed and dissociated forms in solution. In this study, toxicity of free PEI or PEI/ DNA complex was investigated. Human embryonic kidney 293 cells were incubated with free PEI or PEI/DNA complex for 4 hrs. Then, the cells were analyzed at 6, 24, 48, and 96 hrs after the incubation. In MTT assay, the viability of the cells incubated with PEI/DNA complex was continuously decreased with time, while that of the cells incubated with free PEI was not. On the contrary, the expression level of the luciferase gene increased gradually along with time. Release of DNAs from the complexes for transcription produces free PEIs in the cells. This process may proceed slowly due to high charge density of PEI and may be related to delayed toxicity. In addition, apoptotic cells were observed only in the cells incubated with the PEI/DNA complex from 24 hrs after the incubation. The results suggest that PEI/DNA complex contributes to the delayed toxicity by inducing apoptosis and that the delayed toxicity may be related to decomplexation of the complexes in the cells.

• 펄프종이기술
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• 제29권3호
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• pp.26-33
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• 1997

The bacterial celluloses are very different in its physical, chemical and morphological structures compared to wood cellulose. These fibers have many unique properties that are potentially and commercially beneficial. This study was aimed to elucidate the production of bacterial celluloses and to improve their physical properties by chemical pretreatment. Bacterial celluloses produced by static culture had gel-like pellicle structure. The pellicle thickness was increased with the increasing time, and its layer was about 1.8cm after one-month incubation. The pellicles extruded from the cells of Acetobacter had a non-crystalline structure during initial growing stages, gradually getting crystaliyzed with the incubation time elapse, and eventually fumed to the cellulose I crystals. Young＇s modulus of bacterial cellulose sheet was increased with increasing NaOH concentration, and resulted in the highest at 5% NaOH concentration. Similar results with NaClO3 pretreatment can be observed. Too concentrated alkali solutions induced the destruction of cellulose fibrils and changed the mechanical properties of the sheets. These alkaline pretreatment have removed non-cellulosic components(NCC) from the bacterial cellulose, and enhanced inter-abrillar bonding by direct close contact among cellulosic fibrils.

• 현장농수산연구지
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• 제3권1호
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• pp.79-84
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• 2001

오리엔탈 나리의 기내 인편배양 자구의 경출엽 유기를 위한 제요인 구명으로 자구의 크기, 저온처리기간, 기내 배양기간에 따른 경출현 발생과 자구비대를 실험한 결과 대자구가 중, 소자구보다 경출현이 좋았으며 구근비대도 양호했다. 'Acapulco' 대자구에서 95%로 가장 높았고 'Casablanca' 품종의 소자구에서는 전혀 경출현이 되지 않았다. 휴면타파를 위한 저온처리는 최소한 9주이상 소요되었으며 저온처리 6주에서는 경출엽현이 낮고 자구의 비대도 저조하였다. 배양기간이 길어질수록 경출현 발생이 높았고 자구중도 많이 나갔다.