• 분석과학
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• 제35권1호
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• pp.1-7
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• 2022

This study suggests a new one-step fluorescent cyanoacylate-fuming method for developing fingerprints by using a CAB mixed with dimethylaminobenzalde (DMAB) and cyanoacylate (CA) in a specific ratio. CAB is prepared by mixing 2.5 % (w/w) DMAB with CA and fumigated at 180 ℃. Under these conditions, developing fingerprints showed the best results. The fuming method using CAB develops latent fingerprints into fluorescence and has a higher sensitivity than CA, and it showed comparable or better contrast to existing fluorescence enhancement methods. It was also applicable on a variety of non-porous surfaces that can be encountered at ordinary times. This method is more useful than conventional fluorescent dyeing methods in that it minimizes damage to fingerprints or samples, makes it easy to manufacture, saves time, and can use existing current equipment as it is.

• 한국식품영양과학회지
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• 제22권3호
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• pp.307-312
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• 1993

감잎의 메탄올 추출물이 Salmonella typhimurium TA100에서 aflatoxin B$_1$(AFB$_1$), DMAB, MNNG, 그리고 4-NQO의 돌연변이 유발성을 억제시키는 효과가 있었다. 메탄올 추출물을 다시 hexane, chloroform, ethyl acetate, butanol, 그리고 수용성층으로 분획하여 각 획분의 수득율과 항돌연변이 효과를 조사하였다. Hexane, butanol, 그리고 수용성 획분의 수득율이 높았으며, 이중 hexane 획분이 AFB$_1$, DMAB, MNNG, 그리고 4-NQO에 대한 Salmonella typhimurium TA100에서 항돌연변이효과가 가장 크게 나타났다. Hexane 획분을 silica gel column과 thin layer chromatography (TLC)법으로 연속분리하여 TLC상에서 8개의 bands로 분리하였다. 그중 항돌연변이 효과가 가장 컸던 band를 hexane/ethylacetate (1 : 1, v/v)로 추출한 다음 그중에 존재하는 화합물을 GC-MS를 이용하여 분리동정하였다. 활성획분에서는 1'-oxocannabinol, 3$\beta$-acetoxy-17-methyl-5$\alpha$-18 (13-17) abeoard-rost-13-ene, 4-methoxy-2'6'-dinitro-3,5-di-t-butylbiphenyl, 8, 9-dihydro-5,6-dimethoxy-dibenz［c,h］isoquino ［2, 1, 8-1ma］carbazole-11, 16-dione 등이 분리동정되었다.

• 한국표면공학회지
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• 제27권2호
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• pp.109-117
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• 1994

Effect of ultrasonic agitation on the contact properties was studied in Ni electroless plating and Pd activation. P-type Si bare wafers were used as substrate and DMAB was used as reducing agent due to its good electrical properties, solderability and compatibility to substrate. In activation, high density Pd nuclei of small size were formed during ultra-sonic agitation compared to that of no stirring. In electroless plating, the plating rate was enhanced by 30∼90% by using ultrasonic agitation. In elecrtoless plating, inhibitor is the most effective additives in ultrasonic agitation. In this experi-ment, thiourea was used as inhibitor. The less the amount of the inhibitor, the more ultrasonic agitation efficiency. It is confirmed by SEM that Ni-B films formed by ultrasonic were coarser, less porous, and denser than those of no stirring. In ultrasonic agitation, boron content of the films was more than those of no stirring. In this case, the more DMAB concentration, the higher the temperature, the less pH, the more boron content. Resistivity of the films formed by ultrasonic agitation was higher than that of no strirring. As the content of boron was increased, the resistivity of the films was increased exponentially.

• 한국식품영양과학회지
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• 제27권2호
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• pp.350-358
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• 1998

The antimutagenic and anticancer activities of glycoprotein(GP) and chondroitin sulfate(CS) from sea cucumbers were studied using Ames mutagenicity test and human cancer cells culture test. The GP's inhibitory effect toward aflatoxin B1(AFB1) and 3, 2'-dimethyl-4-amino-biphenyl(DMAB) increased with the higher added concentrations up to 5% level(w/w) regardless fractionation methods. The GP from sea cucumbers through DEAE-cellulose column chromatography showed an inhibitory effect ranged from 84 to 98%, and the maximum antimutagenicities resulted in red sea cucumber with 98% (AFB1) and 95% (DMAB). But 5% level of CS from various sea cucumbers had an inhibitory effect toward those both indirect mutagens ranged from 79% to 85%. However, in case of direct mutagens(N-methyl-N'-nitro-N-nitrosoguanidine, MNNG and 4-nitroquinoline-1-oxide, 4-NQO), the GP's inhibitory effect was 55∼78% and the CS had a low inhibitory effect(58∼70%) at the added level of 5%. The GP from sea cucumbers exhibited the strong inhibitory effects with 89∼95% and 82∼92% on the growth of HT-29 human crcinoma cells and AZ-521 human gastric cancer cells (at 5% level).

• 한국표면공학회지
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• 제26권4호
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• pp.175-182
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• 1993

Electroless plating of nickel was studied electrochemically in the presence of complexing agents. Nickel sulfate solution with dimethylamine borance(DMAB) as the reducing agent was used. Effects of temperature pH, concentration and complexing agents-citric acid, EDTA, tartaric acid-were studied.Experimental meas-urements showed that the rate of electroless nickel deposition was closely related to electrochemical parame-ters such as temdperature, pH, concentration and the properties of complexing agets.

• 한국식품영양과학회지
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• 제24권6호
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• pp.880-886
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• 1995

감잎 열수 추출물 및 감잎 탄닌의 항돌연변이 효과를 Ames test, spore rec assay 및 SOS chromotest 방법을 이용하여 검토하엿다. Salmonella typhimurium TA100에서 aflatoxin $B_{1}(AFB_{1})$, dimethyl-amino-biphenyl(DMAB)와 같은 간접 돌연변이워에 대해서 뿐만아니라 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), 4-nitroquinoline-1-oxide(4-NQO)와 같은 직접 돌연변이원에 대해서도 강력한 항돌연변이성을 관찰할 수 있었다. Bacillus subtilis H17($rec^{+}$)와 M45($rec^{-$)를 사용한 spore rec assay에서도 감잎 탄닌은 MNNG에 대한 강한 항돌연변이 효과를 나타내었고, Escherichia coli PQ37을 사용한 SOS chromotest에서도 4-NQO의 돌연변이성이 크게 저해되었다. 또한 감잎차 부터 탄닌을 추출하여 이미 그 효과가 알려진 녹차 탄닌과 함께 항돌연변이 효과를 살펴본 결과 시료의 농도에 비례해서 녹차탄니과 비슷한 수준으로 현저한 항돌연변이 효과를 나타내었다. 이들 항돌연변이 실험계에서 감잎 탄닌이 감잎 열수 추출물에 비해 활성이 크게 나타났다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2013년도 춘계학술대회 논문집
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• pp.137-137
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• 2013

본 연구에서는 반도체 검사 장비인 프로브 카드의 핵심 부품인 프로브 니들의 팁 부분의 내마모성을 향상시키기 위하여 무전해 Ni-B-W 합금 도금 실험을 실시하였다. 무전해 Ni-B-W 합금 도금 실험에서 여러 가지 제어인자 중 도금욕의 pH와 온도 그리고 환원제의 농도 등을 변수로 하였다. 도금욕 pH와 온도에 따른 전착속도 및 물성 변화를 관찰하였으며, 환원제 농도 변화에 의한 open circuit potential의 변화를 측정하였다.

• 한국표면공학회지
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• 제29권6호
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• pp.714-719
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• 1996

For the fabrication of the circuits, contact or terminal areas are usually coated with nickel and gold. Usually, diluted palladium solution is applied to initiate electroless nickel plating on the copper circuits. However, the trace amounts of palladium remains on the resin and it causes the extraneous deposition. We confirmed that selectivity was greatly improved by the treatment with the strong reducing agents such as SBH or DMAB. Bondability was greatly influenced by the contents of phosphorus in the deposited nickel. Stabilizers in the electroless gold plating were also influenced the bonding strength. The baths containing cupferron or potassium nickel cyanide as a stabilizer showed superior bondability. The gold deposits having strong orientation with Au(220) and Au(311) showed good bond ability.

• 한국표면공학회지
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• 제45권3호
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• pp.97-105
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• 2012

The effects of pH, types of applied current, agitation method and time, additive on the amount of co-deposited $TiO_2$ particles in the matrix were investigated. The deposition rates increased with increasing pH values, while the volume fraction of $TiO_2$ particles and the size of agglomerated $TiO_2$ particles in the composite decreased. The volume fraction of $TiO_2$ particles in the composite decreased when pulsed current of 50% duty cycle was used. And the size of agglomerated $TiO_2$ particles in the nickel matrix of pulsed current was smaller than that of DC current specimen. The volume fraction of $TiO_2$ particles in the matrix decreased with longer time by air agitation, but in case of using magnetic bar, volume fraction in the same range of time was relatively constant. The volume fraction of the electrodeposited Ni-$TiO_2$ composite in the solution containing 0.01 M Dimethylamine borane (DMAB) increased slightly with increasing agitation time regardless of agitation methods. Thermal stability of the electrodeposited Ni-$TiO_2$ composite increased with lower pH at the temperature range of $200{\sim}800^{\circ}C$, and the results showed that the amount of co-deposited $TiO_2$ relies more on the deposition rate than zetapotential of $TiO_2$ particles.

• Clinical and Experimental Reproductive Medicine
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• 제45권2호
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• pp.75-81
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• 2018

Objective: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. Methods: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at $36^{\circ}C$ for 3 more weeks. Results: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. Conclusion: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.