• 대한화학회지
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• 제53권1호
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• pp.27-33
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• 2009

실제 시료에 들어있는 흔적량 Cd(II)를 2-mercaptobenzothiazole이 내포되어 있는 미세결정 p-dichlorobenzene에 예비농축시킨 후 정량하는 감도좋은 방법을 개발하였다. 시료 용액의 pH, 킬레이트제 2-mercaptobenzothiazole의 양, 흡착제 p-dichlorobenzene-2-MBT의 양 그리고 시료 용액의 흐름속도 등 여러 실험조 건을 최적화하였다. 여러 공존이온에 대한 방해효과를 조사하였는데 다른 이온들보다 Cu(II)가 비교적 심하게 방해를 하였다. 그러나 Cu(II)에 의한 방해는 시료용액의 tartrate 이온의 농도를 0.01 M이 되게 하든지 또는 0.20 g의 p-dichlorobenzene에 내포된 2-mercaptobenzothiazole의 양을 0.08 g에서 0.12 g이 되게 하면 충분히 없앨 수 있었다. 이 방법에 의해 얻어진 직선 감응범위, 상관계수($R^2$) 및 검출한계는 각각 0.5-30 ng $mL^{-1}$, 0.9962, 및 0.39 ng $mL^{-1}$로서, p-dichlorobenzene을 흡착제 매질로 이용하여 매우 좋은 결과를 얻었다. 이 방법을 실제 시료에 적용할 수 있을지를 확인하기 위해 수용액 시료(폐수, 시냇물, 그리고 저수지물)와 플라스틱 시료에 응용하였다. 회수율은 93-104% 정도였으며, ICP-MS를 이용하여 얻은 값과 이 방법으로 얻은 값은 F 시험법에 의하면 95% 신뢰수준에서 차이가 없는 것으로 나타났다. 실험 결과들로부터 이 방법은 여러 실제 시료에 들어있는 Cd(II)을 농축 정량하는데 응용할 수 있음을 알 수 있었다.

• 한국전문물리치료학회지
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• 제10권3호
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• pp.17-27
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• 2003

Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. Therefore, rTMS of high or low frequency over motor cortex may change certain aspects of motor learning performance and cortical activation. This study investigated the effect of high and low frequency subthreshold rTMS applied to the motor cortex on motor learning of sequential finger movements and brain activation using functional MRI (fMRI). Three healthy right-handed subjects (mean age 23.3) were enrolled. All subjects were trained with sequences of seven-digit rapid sequential finger movements, 30 minutes per day for 5 consecutive days using their left hand. 10 Hz (high frequency) and 1 Hz (low frequency) trains of rTMS with 80% of resting motor threshold and sham stimulation were applied for each subject during the period of motor learning. rTMS was delivered on the scalp over the right primary motor cortex using a figure-eight shaped coil and a Rapid(R) stimulator with two Booster Modules (Magstim Co. Ltd, UK). Functional MRI (fMRI) was performed on a 3T ISOL Forte scanner before and after training in all subjects (35 slices per one brain volume TR/TE = 3000/30 ms, Flip angle $60^{\circ}$, FOV 220 mm, $64{\times}64$ matrix, slice thickness 4 mm). Response time (RT) and target scores (TS) of sequential finger movements were monitored during the training period and fMRl scanning. All subjects showed decreased RT and increased TS which reflecting learning effects over the training session. The subject who received high frequency rTMS showed better performance in TS and RT than those of the subjects with low frequency or sham stimulation of rTMS. In fMRI, the subject who received high frequency rTMS showed increased activation of primary motor cortex, premotor, and medial cerebellar areas after the motor sequence learning after the training, but the subject with low frequency rTMS showed decreased activation in above areas. High frequency subthreshold rTMS on the motor cortex may facilitate the excitability of motor cortex and improve the performance of motor sequence learning in normal subject.

• Composites Research
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• 제18권4호
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• pp.27-34
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• 2005

염수시험기를 통해 6개월 동안 염수분무시험과 염수침수시험을 수행함으로써 염수환경에 노출된 유리섬유직물페놀 복합재의 내구성을 실험적으로 조사하였다. 이때 염수환경에 노출된 시간에 따른 인장특성, 굽힘특성, 전단특성 등의 기계적 특성을 평가하고 동역학 측정장치를 적용하여 저장전단탄성계수. 손실전단탄성계수, tan $\delta$ 등의 열분석 특성을 측정하였다. 또한 적외선 분광분석기를 적용하여 염수환경에의 노출시간에 따른 화학구조의 변화를 분석하였다. 연구결과에 따르면 기계적 특성과 열분성 특성은 노출시간에 민감하게 변하며 노출시간이 길어짐에 따라 점차 감소되는 양상을 나타낸다. 그러나 강성의 경우에는 염수환경에 노출되면 복합재의 가소화로 인해 노출의 초기에는 감소하기 시작하고 노출시간이 길어짐에 따라 복합재의 팽창, 수지의 소성화, 가교 결합의 증가 등으로 인해 다소 증가하는 양상을 나타내지만 노출시간이 더욱 더 길어지면 점차 감소할 것으로 추측된다. 또한 FT-IR 선도에서의 피크 형상과 위치는 노출시간에 큰 영향을 받지 않으며 피크 세기는 노출시간에 따라 달라진다. 마지막으로 염수침수환경은 염수분무환경에 비해 유리섬유직물/복합재의 내구성에 더욱 심각한 영향을 미침을 알 수 있었다.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.27-31
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• 2010

The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

• 동의생리병리학회지
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• 제27권6호
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• pp.782-788
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• 2013

Chrysanthemum zawadskii Herbich var. latilobum Kitamura (Compositae), colloquially known "Gujulcho" in Korea, has been used in traditional medicine for the treatment of various diseases, including cough, common cold, bladder-related disorders, gastroenteric disorders, hypertension, and inflammatory diseases, such as pneumonia, bronchitis, pharyngitis, and rheumatoid arthritis (RA) However, the effect of Chrysanthemum zawadskii var. latilobum on breast cancer invasion is unknown. In this study, we investigated the inhibitory effect of Chrysanthemum zawadskii var. latilobum extract (CZE) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced matrix metalloproteinase-9 (MMP-9) expression and cell invasion, as well as the molecular mechanisms involved in MCF-7 cells. CZE were not cytotoxic up to 100 ${\mu}g/ml$ concentration in the MCF-7 cell line. CZE decreased MMP-9 expression. TPA substantially increased NF-${\kappa}B$ DNA binding activity. Pre-treatment with CZE inhibited TPA-stimulated NF-${\kappa}B$ binding activity and NF-${\kappa}B$ related protein expression. To identify invasion ability of MCF-7 cells decreased by CZE, we used martrigel invasion assay. As a result, it is significantly decreased cell invasion. These results indicate that CZE-mediated inhibition of TPA-induced MMP-9 expression and cell invasion involves the suppression of the NF-${\kappa}B$ pathway in MCF-7 cells. Chrysanthemum zawadskii var. latilobum may have potential value in restricting breast cancer metastasis.

• 대한교통학회지
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• 제27권2호
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• pp.15-22
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• 2009

도시철도 수요를 일반적인 4단계 모형에 의해서 역별로 추정하는 경우에는 몇 가지 한계가 존재한다. 첫째 행정동 기반 사회경제지표를 토대로 하므로 행정동 단위의 도시철도 수요가 추정될 수밖에 없다. 그러나 각 행정동에 1개만이 아닌 2개 이상의 역이 위치할 경우 행정동 단위의 수요를 2개 이상의 역에 적절하게 할당하기가 쉽지 않다. 둘째 역별 도시철도 수요는 행정동보다 공간적 범위가 좁은 역세권 특성에 커다란 영향을 받게 된다. 그러므로 역세권보다 넓은 행정동 전체 특성을 기반으로 한 도시철도 수요 추정과 역별 할당에 의한 역별 수요 추정은 부정확할 수밖에 없다. 위와 같이 행정동을 기반으로 한 자료 사용의 한계로 도시철도 역별 수요를 제대로 추정하기 어려운 점이 존재하여, 본 연구에서는 크게 두 가지 방안을 검토하였다. 첫째는 행정동이 아닌 역세권을 기반으로 하는 사회경제지표 자료를 토대로 역별 수요를 추정하는 방안이다. 그러나 이 방안은 자료 수집과 분석에 너무 많은 시간과 노력이 소요되는 것에 비하여, 추정의 정확도는 크게 높아지지 않는 것으로 나타났다. 둘째는 일반적인 4단계모형을 적용하되 역세권 특성을 반영하기 위해 행정동 센트로이드 위치 및 도시철도 역과의 커넥터 거리를 각 역별로 조정하여 역세권을 반영하는 방안이다. 행정동 센트로이드 위치 및 커넥터 거리를 조정하는 두 번째 방법을 적용하여 역별 수요를 추정한 결과를 실제 집계된 서울시 지하철의 역별 수요를 비교한 결과, 각 역별로 매우 근사한 결과를 나타내었다.

• 대한환경공학회지
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• 제37권8호
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• pp.492-497
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• 2015

휘발성 유기화합물인 VOCs (Volatile Organic Compounds)는 주로 도색 공정이나 유기용제를 사용하는 업체나 세탁소 등에서 발생된다. 이는 다양한 형태의 탄화수소로 구성되어 있으며 대기 중에 방출되어 희석되므로 그 농도가 낮아 발열량이 크지 않기 때문에 일반 연소기로는 직접 소각처리가 어렵다. 본 연구에서는 이와 같이 저열량 가스인 VOC를 처리하기 위해 새로운 형태의 플라즈마-덤프 연소기를 제안하였다. 이 연소기는 플라즈마 버너와 덤프 연소기 그리고 3D 매트릭스 버너의 특성이 조합된 형태로 이루어졌다. 따라서 본 연소기는 안정적인 화염형성과 VOC 분해에 필요한 충분한 분해온도와 체류시간을 확보할 수 있는 구조로 되어있다. 플라즈마-덤프 연소기의 성능특성을 규명하기 위해 모사 VOC를 톨루엔으로 하여 VOC 공급량과 농도 그리고 VOC 인젝터 위치 등에 대해 실험을 수행하였다. VOC 인젝터 위치를 바깥쪽으로 하여 톨루엔의 농도가 3,000 ppm인 VOC를 450 L/min 공급한 경우 VOC 분해효율이 89.64%이고 에너지 효율은 1.227 kg/kWh으로 기존의 연소기에 비해 우수한 성능을 보였다.

• Journal of Pharmaceutical Investigation
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• 제27권4호
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• pp.303-311
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• 1997

Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

• 한국환경농학회지
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• 제19권5호
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• pp.382-393
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• 2000

The principal indicators contributing to water qualities was screened by factor analyses, based on the monitored chemical parameters of water quality for various water resources from 1995 to 1999 in the small agricultural catchments of the Han River Basin. Water samples of streams, groundwaters, and reservoirs were taken four times a year from upper (Daegwanryong), middle (Dunnae and Chunchon) and lower (Guri) reaches of Han River Basin. In these areas, the respective type of farming practiced was alpine agriculture and livestocks raising, typical upland and paddy cultivation, and intensive cropping in the plastic film house. Water quality was monitored for twenty-one water quality parameters, including pH, EC, SS, T-N, T-P, COD, cations, anions, and heavy metals. pH, EC and COD of the stream waters were suitable for the Korea irrigation water quality guidelines. However, T-N and T-P concentrations of water samples in four catchments far exceeded the irrigation water guideline. Concentrations of canons and heavy metals in Wangsuk stream in Guri area were higher than those in streams in other areas. Factor analysis revealed that significant correlation was observed for 81 pairs out of 231 water quality indicators of stream water among the $21\;{\times}\;21$ cross correlation matrix of stream water quality indicators. The first factor accounted for 27.01% of the total variation in stream water quality indicators, and high positive factor loadings were shown on EC, K, Na, $NH_4\;^+-N$, $PO_4\;^{3-}$, $SO_4\;^{2-}$, and COD. Fifty-three water quality indicator pairs were significant out of 190 ground water quality parameters. The first factor accounted for 28.54% of the total variation in ground water quality indicators, and high loadings were revealed on EC, Ca, Mg, K, Na, $NH_4\;^+-N$, and $SO_4$. Twenty-nine pairs of reservoir water quality indicators were significant out of 66 pairs. The first factor accounted for 37.06% of the total variation in reservoir water quality indicators, and high loadings were shown on EC, Mg, K, Na, SS, T-P, Cl, and COD. These results demonstrate that EC was the first factor contributing to water quality.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1392-1400
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• 2017

Galactooligosaccharides (GOSs) are known to be selectively utilized by Bifidobacterium, which can bring about healthy changes of the composition of intestinal microflora. In this study, ${\beta}-GOS$ were synthesized using bifidobacterial ${\beta}-galactosidase$ (G1) purified from recombinant E. coli with a high GOS yield and with high productivity and enhanced bifidogenic activity. The purified recombinant G1 showed maximum production of ${\beta}-GOSs$ at pH 8.5 and $45^{\circ}C$. A matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the major peaks of the produced ${\beta}-GOSs$ showed MW of 527 and 689, indicating the synthesis of ${\beta}-GOSs$ at degrees of polymerization (DP) of 3 and DP4, respectively. The trisaccharides were identified as ${\beta}-{\text\tiny{D}}$-galactopyranosyl-($1{\rightarrow}4$)-O-${\beta}-{\text\tiny{D}}$-galactopyranosyl-($1{\rightarrow}4$)-O-${\beta}-{\text\tiny{D}}$-glucopyranose, and the tetrasaccharides were identified as ${\beta}-{\text\tiny{D}}$-galactopyranosyl-($1{\rightarrow}4$)-O-${\beta}-{\text\tiny{D}}$-galactopyranosyl-($1{\rightarrow}4$)-O-${\beta}-{\text\tiny{D}}$-galactopyranosyl-($1{\rightarrow}4$)-O-${\beta}-{\text\tiny{D}}$-glucopyranose. The maximal production yield of GOSs was as high as 25.3% (w/v) using purified recombinant ${\beta}-galactosidase$ and 36% (w/v) of lactose as a substrate at pH 8.5 and $45^{\circ}C$. After 140 min of the reaction under this condition, 268.3 g/l of GOSs was obtained. With regard to the prebiotic effect, all of the tested Bifidobacterium except for B. breve grew well in BHI medium containing ${\beta}-GOS$ as a sole carbon source, whereas lactobacilli and Streptococcus thermophilus scarcely grew in the same medium. Only Bacteroides fragilis, Clostridium ramosum, and Enterobacter cloacae among the 17 pathogens tested grew in BHI medium containing ${\beta}-GOS$ as a sole carbon source; the remaining pathogens did not grow in the same medium. Consequently, the ${\beta}-GOS$ are expected to contribute to the beneficial change of intestinal microbial flora.