• Asian Pacific Journal of Cancer Prevention
• /
• 제14권10호
• /
• pp.5855-5860
• /
• 2013

Phytochemicals are among the natural chemopreventive agents with most potential for delaying, blocking or reversing the initiation and promotional events of carcinogenesis. They therefore offer cancer treatment strategies to reduce cancer related death. One such promising chemopreventive agent which has attracted considerable attention is sulforaphane (SFN), which exhibits anti-cancer, anti-diabetic, and anti-microbial properties. The present study was undertaken to assess effect of SFN alone and in combination with a chemotherapeutic agent, gemcitabine, on the proliferative potential of MCF-7 cells by cell viability assay and authenticated the results by nuclear morphological examination. Further we analyzed the modulation of expression of Bcl-2 and COX-2 on treatment of these cells with SFN by RT-PCR. SFN showed cytotoxic effects on MCF-7 cells in a dose- and time-dependent manner via an apoptotic mode of cell death. In addition, a combinational treatment of SFN and gemcitabine on MCF-7 cells resulted in growth inhibition in a synergistic manner with a combination index (CI)<1. Notably, SFN was found to significantly downregulate the expression of Bcl-2, an anti-apoptotic gene, and COX-2, a gene involved in inflammation, in a time-dependent manner. These results indicate that SFN induces apoptosis and anti-inflammatory effects on MCF-7 cells via downregulation of Bcl-2 and COX-2 respectively. The combination of SFN and gemcitabine may potentiate the efficacy of gemcitabine and minimize the toxicity to normal cells. Taken together, SFN may be a potent anti-cancer agent for breast cancer treatment.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권10호
• /
• pp.5131-5136
• /
• 2012

Cancer is one of the major health problems worldwide and its current treatments have a number of undesired adverse side effects. Natural compounds may reduce these. Currently, a few plant products are being used to treat cancer. In this study, goniothalamin, a natural occurring styryl-lactone extracted from Goniothalamus macrophyllus, was investigated for cytotoxic properties against cervical cancer (HeLa), breast carcinoma (MCF-7) and colon cancer (HT29) cells as well as normal mouse fibroblast (3T3) using MTT assay. Fluorescence microscopy showed that GTN is able to induce apoptosis in HeLa cells in a time dependent manner. Flow cytometry further revealed HeLa cells treated with GTN to be arrested in the S phase. Phosphatidyl serine properties present during apoptosis enable early detection of the apoptosis in the cells. Using annexin V/PI double staining it could be shown that GTN induces early apoptosis on HeLa cells after 24, 48 and 72 h. It could be concluded that goniothalamin showing a promising cytotoxicity effect against several cancer cell lines including cervical cancer cells (HeLa) with apoptosis as the mode of cell death induced on HeLa cells by Goniothalamin was.

• 한국항행학회논문지
• /
• 제22권3호
• /
• pp.179-188
• /
• 2018

항공전자 시스템의 개발할 때 항공 사고를 예방하기 위해서 SAE ARP4761 (민간 항공 시스템 및 장비 안전성 평가 프로세스 수행 방법 및 지침) 규격에 명시된 안전성 분석 및 평가를 수행한다. 안전성 분석은 시스템의 정상상태가 아닌 비정상상태에 대한 지식과 다른 규격들 간의 상호 연관성에 대한 지식이 요구된다. 때문에, 안전인증규격의 준수를 입증하는 자료를 자동으로 출력하는 도구가 필요하다. 본 연구는 규격의 안전성 분석 절차를 도식화하고, 안전 분석 CAD 도구들을 개별 절차에 적용하는 방법을 연구하였다. 예시 연구로서, ARP4761 부록의 여객기용 휠 제동 시스템 (WBS; wheel brake system)을 대상으로 ARP4761분석을 수행하였다.

• 한국정보통신학회논문지
• /
• 제13권6호
• /
• pp.1141-1149
• /
• 2009

Pulse 펄스형 Nd:YAG 레이저는 피부재생치료에 적합하고, 램프에 의해서 연속발진은 물론 정상발진, Q-스위치 및 모드동기 발진까지 다양한 발전 형태가 가능하며 미세수술 및 피부재생 촉진에 널리 사용되어지고 있다. 치료목적에 따라 에너지 밀도를 제어하는 것이 매우 중요하다. 에너지 밀도의 제어는 레이저 출력의 펄스반복률을 제어하는 방법이 주로 사용된다. 본 연구에서는 펄스형 Nd:YAG 레이저의 펄스반복률을 제어할 수 있는 제 2고조파 발생(second harmonic generation: SHG)로 각주파수인 광파의 에너지 일부가 비선형 결정안을 전파하면서 각주파수인 광파의 에너지로 변환되는 현상을 적용하여 2차 비선형성에 의한 제2고조파 발생을 통해 피부심부까지 치료 가능하다는 것은 간단히 관찰할 수 있었다.

• 한국의학물리학회지:의학물리
• /
• 제27권3호
• /
• pp.162-168
• /
• 2016

Proton therapy is increasingly being actively used in the treatment of cancer. In contrast to photons, protons have the potential advantage of delivering higher doses to the cancerous tissue and lower doses to the surrounding normal tissue. However, a range shifter is needed to degrade the beam energy in order to apply the pencil beam scanning technique to tumors located close to the minimum range. The secondary neutrons are produced in the beam path including within the patient's body as a result of nuclear interactions. Therefore, unintended side effects may possibly occur. The research related to the secondary neutrons generated during proton therapy has been presented in a variety of studies worldwide, since 2007. In this study, we measured the magnitude of the secondary neutron dose depending on the location of the detector and the use of a range shifter at the beam nozzle of the proton scanning mode, which was recently installed. In addition, the production of secondary neutrons was measured and estimated as a function of the distance between the isocenter and detector. The neutron dose was measured using WENDI-II (Wide Energy Neutron Detection Instruments) and a Plastic Water phantom; a Zebra dosimeter and 4-cm-thick range shifter were also employed as a phantom. In conclusion, we need to consider the secondary neutron dose at proton scanning facilities to employ the range shifter reasonably and effectively.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권12호
• /
• pp.624-630
• /
• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• 한국작물학회지
• /
• 제44권1호
• /
• pp.86-94
• /
• 1999

A set of rice recombinant inbred lines was developed from a cross between a Tongil type variety, Nonganbyeo, and an indica variety, BG276, by the single seed descent method. The number of the lines in the population was 272. All the agronomic characters studied except ADV (alkali-digestion value) showed continuous variation among the RILs, implying that their inheritance mode should be quantitative. The patterns of the variation in the RILs were either normal or skewed distribution. ADVs of RILs were segregated into two groups with 1:1 ratio, indicating that ADVs in this KIL population might be controlled by one major gene. Transgressive variations were also observed in all characters. Heritability values of the characters varied from 0.488 in brown/rough rice ratio to 0.895 in alkali-digestion value. In the analysis of genotypic and phenotypic correlations, the character of yield was positively correlated with 8 different agronomic characters. The number of panicles per hill was negatively correlated with culm length, panicle length, and number of spikelets per panicle. Grain length was positively correlated with grain width, grain thickness, grain length/width ratio, white belly, ADV, and amylose. However, grain length/width ratio was negatively correlated with grain width. White core was also negatively correlated with white belly and ADV.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2011년도 추계학술대회 논문집
• /
• pp.325-330
• /
• 2011

RCP(Reactor coolant pump) must be designed to preserve it's functions on normal or abnormal environments and seismic event same as operating basis earthquake(OBE) and safe shutdown earthquake(SSE). Generally, there are static and dynamic analytical method which can be applied by a floor response spectrum or time history analysis for the seismic qualification. Initially, It was accomplished a detailed structural FE-model for finite element analysis on the bases of 3-dimensional solid model which was made by the RCP drawing. As the result of dynamic characteristic using the detailed FE-model, it's shown about 12Hz natural frequency of 1st bending mode shape and maximum displacement has 11mm with the structural bending by single-point response spectrum(SPRS) method at all elevation. But maximum displacement has 7.6mm by multi-point response spectrum(MPRS) method which was applied to the three floor response spectrum at each elevation. Therefore, On a large heighten structures as RCP, The application by SPRS method causes to be more conservative results. Finally, A simpled equivalent beam model which was developed by use of iteration of detailed FE-model is shown the result more similar with those of natural frequencies and SPRS analysis. And maximum equivalent stress and displacement of the simpled beam has verified with 180MPa and 7.1mm each at 15sec as results by SSE time history method.

• 한국소음진동공학회논문집
• /
• 제23권1호
• /
• pp.65-72
• /
• 2013

This case study presents a practical method to reduce resonant vibration of large vertical pumps. The pumps are driven at 400 rpm rated speed by induction motor. The vibration was not significantly large when operated at this rated speed. Large vibration was occurred when the pump was operated below the rated speed for flow control. Due to the large vibration resonance, variable speed operation of the pump was not possible for several months at worst cases. To find an efficient vibration control method, the flexural responses of pumps for both normal and transient operations were measured. The measured modal characteristics were compared with those of finite element analysis. When the pump was operated at a specific rpm, the natural mode whose resonance frequency is twice the rotating angular speed induced the large vibration. The retrofit utilizing stiffeners to reduce this resonant vibration were performed. Effects of designed stiffeners on reducing vibration were validated through tests after actual installation.

• 공업화학
• /
• 제8권2호
• /
• pp.286-291
• /
• 1997

항암제로 탁월한 효능이 있는 taxol을 정상 액체 크로마토그래피를 이용하여 주목나무의 추출물에서 분리하였다. Taxol을 분리하기 위해 시료 주입량은 $5{\mu}l$에서 $100{\mu}l$로 변화시키고, 이동상 유속은 1ml/min로 고정하여 일정 용매법으로 실험을 하였다. 실험에 사용된 이동상은 헥산, 에탄올, 메탄올, 1-프로판올, 이소프로판올이었다. Taxol과 유사한 성질를 갖는 표준시료 cephalomannine, taxol, 10-deacetyltaxol의 혼합물에서 taxol을 분리하였다. Cephalomannine, taxol, 10-deacetyltaxol 혼합물의 분리 실험 결과로 taxol의 분리 최적 조건은 2성분계에서 헥산/에탄올의 부피 조성비가 96/4이며, 3성분계에서는 헥산/1-프로판올/메탄올의 부피 조성비가 96/2/2이었다. 분리시간은 2성분계에서 80분인데 비해 3성분계에서는 50분으로 적은 용매를 사용하여 분리할 수 있었다. 위에서 얻는 실험조건으로 실제 주목나무의 추출물 $1{\mu}g$에서 taxol를 분리할 수 있었다.