• Investigative Magnetic Resonance Imaging
• /
• v.1 no.1
• /
• pp.114-118
• /
• 1997

Purpose: Functional MR imaging is the method of demonstrating changes in regional cerebral blood flow produced by sensory, motor, and any other tasks. Functional MR of visual cortex is performed as a patient stares a photic stimulation, so adaptable photic stimulation is necessary. The purpose of this study is to evaluate whether the size of photic stimulator can affect the degree of visual cortex activation. Materials and Methods: Functional MR imaging was performed in 5 volunteers with normal visual acuity. Photic stimulator was made by 39 light-emitting diodes on a plate, operating at 8Hz. The sizes of photic stimulator were full field, half field and focal central field. The MR imager was Siemens 1.5-T Magnetom Vision system, using standard head coil. Functional MRI utilized EPI sequence (TR/TE= 1.0/51. Omsec, matrix $No.=98{\times}128$, slice thickness=8mm) with 3sets of 6 imaging during stimulation and 6 imaging during rest, all 36 scannings were obtained. Activation images were obtained using postprocessing software(statistical analysis by Z-score), and these images were combined with T-1 weighted anatomical images. The activated signals were quantified by numbering the activated pixels, and activation a index was obtained by dividing the pixel number of each stimulator size with the sum of the pixel number of 3 study using 3 kinds of stimulators. The correlation between the activation index and the stimulator size was analysed. Results: Mean increase of signal intensities on the activation area using full field photic stimulator was about 9.6%. The activation index was greatest on full field, second on half field and smallest on focal central field in 4. The index of half field was greater than that of full field in 1. The ranges of activation index were full field 43-73%(mean 55%), half field 22-40 %(mean 32%), and focal central field 5-24%(mean 13%). Conclusion: The degree of visual cortex activation increases with the size of photic stimulator.

• Journal of Biosystems Engineering
• /
• v.24 no.3
• /
• pp.217-224
• /
• 1999

우리나라의 경우 각종 장해와 주년 수요의 증가에 따른 불시재배의 증가로 인하여 저온신장성, 병해저항성 등과 같이 작물의 내성증진을 목적으로 접목묘의 이용이 급속도로 신장되고 있다. 특시 연작장해가 심한 박과형 채소류는 대부분 접목재배가 필요한 실정이다. 그러나 국내의 경우, 접목작업은 거의 수작업으로 행해지며 세밀한 조작과 숙련성 그리고 많은 노력을 필요로 한다. 따라서, 접목 생산성을 높일 수 있는 저가의 자동화 시스템 개발이 요구된다. 다양한 접목법들 중 현재 농가에서 가장 광범위하게 이용되고 있는 호접은 삽접 및 절단접에 비하여 자동화가 어렵고 활착 후 절단작업이 부가적으로 필요하나 접목 후 순화공정이 간단하고 활착률이 높다. 본 논문에서는 호접과 삽접에 대하여 접목 후의 활착률 및 접목에 소요되는 작업시간을 비교하였고, 호접법에 의거하여 작업공정을 생력화한 육묘 자동접목 시작기를 개발하였다. 시작기는 농가조합 및 중규모 육묘장의 설비를 지향하여, 묘판 및 접목묘의 취급을 제외하고 1인 접목작업 형태의 자동화 시스템으로 개발하였다. 시작기는 크게 버퍼기능을 부착한 배치형 육묘장치부, 2세트에 공압 매니퓰레이터, 대목과 접수의 원할한 접목을 위해 설계한 특수 그리퍼, 각고 조절형 절단부, 진동형 클립공급부 그리고 자동 클립 장착장치로 구성하였다. 접목 작업시간은 대략 4ch 정도이나 작업시간의 조정이 가능하도록 하였다. 실험실에서 수행한 간이접목 시험 결과, 절단날이 대목과 접수의 접촉부위를 관통할 때 접촉면이 서로 어긋나는 경우가 발생하였으나 육묘들이 호접에 적정한 기하학적 물성 요건을 갖춘다면 80% 이상의 접목 육묘의 기하학적 물성에 따른 체계적인 접목시험이 필요하다.

• Journal of Biomedical Engineering Research
• /
• v.20 no.2
• /
• pp.155-164
• /
• 1999

In this paper, the prototype of SIS(Simulated Implantation System) for human femoral head is introduced. SIS is a software which carries on a virtual femoral head replacement surgery including 3d visualization as well as various numeric analyses between a patient's femur and artificial femur through certain stages of the image processing and of the computer graphics. Also, processes required after acquiring consecutive CT-images and projected image of an artificial femur are discussed, and the corresponding results including prototype of SIS are given.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.75-75
• /
• 2010

배변 후 toilet flushing 시 다량의 세균을 포함한 물방울들이 화장실 곳곳으로 퍼지는 현상이 있다. 이러한 현상을 방지하기 위해 변기 뚜껑에 자기 세정 효과를 갖는 초발수 표면을 위해 플라즈마를 이용한 표면 처리가 시도되고 있으며, 이 연구의 일환으로 flushing시의 변기내의 유동 분석을 초고속 카메라를 이용하여 수행하였다. Toilet flushing 시 물 튀김 현상은 육안으로는 잘 관찰하기 어렵지만 최고 1000 frame/sec의 속도를 갖는 CCD camera를 이용하여 정량적으로 물 튀김에 의한 오염 가능성을 촬영 분석하였다, 두 번째로 소변 시의 변기 표면에서의 튀김현상을 분석하기 위하여 소변의 발사각도 및 속도를 가장 실제와 유사한 조건으로 설정하고 이를 상용 전산 유체 역학 소프트웨어인 CFD- ACE+의 자유 표면 계산 기능과 두 가지 유체(액체 및 기체)의 혼합 계산 모델을 사용한 계산 결과와 비교 하였다. 그 결과 변기 표면의 표면장력을 아주 작게 설정한 경우(작은 접촉각, 친수성)에는 중력의 영향을 고려하였음에도 불구하고 소변이 변기에 충돌 후 상부로 상당부분 튀어 올라가는 결과를 얻었다. 여러 가지 각도와 발사 속도, 실제의 인체와 유사한 발사 부위의 형상 변화로 인한 유체 표면의 난류 발생과 이에 따른 변기 표면 충돌 현상 변화 등을 수치적으로 고찰하였다. 한 예로 5.6 mm 직경의 노즐에서 소변이 나오는 경우를 발사 속도 3 m/s, 각도 $10^{\circ}$로 주고 중력을 고려하여 10초 동안을 계산하면, 방뇨 시 toilet bowl 내부에서의 물의 유동과 toilet 표면을 맞고 튀기는 현상을 그림 1과 같이 볼 수 있었다.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2018.04a
• /
• pp.7-7
• /
• 2018

Morinda 속 식물은 꼭두서니과(Rubiaceae)에 속하는 다년생 상록관목으로서 전세계 80여종이 분포하고 있다. 그중 노니는 2000년 전부터 동남아시아 지역에서 식품, 향신료, 음료, 자양강장제 등 다양한 분야에 사용되고 있으며 뿌리, 줄기, 잎, 열매의 식물체 전체 부위가 이용되고 있다. 특히 열매는 주스 등 다양한 제품으로 만들어지고 있다. 본 연구는 조직배양된 노니 부정근을 재료로 하여 항알러지의 효능평가를 수행하고 지표물질로 rubiadin을 선정하였으며 이물질에 대한 정제방법 및 구조분석을 통해 정성, 정량적 분석방법을 확립하였다. 항알러지 효능에 대한 측정 결과 노니 부정근 조추출물 $100{\mu}g{\cdot}mL^{-1}$에서 약 85%의 높은 발현 억제 효과를 보였고 이를 분획 추출한 후 분획물별로 histamine 및 $TNF-{\alpha}$ 발현 억제효과를 측정한 결과 헥산 및 메틸렌클로라이드층 분획물에서 효과가 우수하였다. 노니 부정근 조추출물이 함유한 유효성분들 중 항알러지 효과를 나타내는 지표물질을 선정하기 위하여 용매분획을 실시한 후 preparative LC로 분취하여 항알러지 효과가 높은 분획물을 얻었다. HPLC로 분취한 화합물을 GC/MS/MS, LC/MS-IT-TOF, UV/VIS spectrophotometer를 이용하여 최종적으로 rubiadin을 확인하고 이 화합물을 지표물질로 선정하였다. 이러한 결과는 노니 부정근의 고부가가치 기능성 소재로 이용되는데 도움이 될 것으로 기대한다.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1982.05a
• /
• pp.16.2-16
• /
• 1982

The palatine tonsils which are located in entrance of digestive and upper respiratory tracts are the most important organ in anatomical and functional structures of the pharyngeal lymphatic tissues. As for function of the tonsil, there have been many suspected theories that were included hematopoietic, hormonal, digestive function and production of vitamin, entry of bacteria with other antigenous materials and defence mechanism of which has taken charge by Virchow in 1860 in past. But among these theories, in recently, defence mechanism of the tonsil was strongly accepted immunologically. For the purpose of elucidating immune response of the tonsil, the author observed serum immunoglobulin levels, peripheral total lymphocyte counts and populations of T, B and Null lymphocytes before and after tonsillectomy in 30 cases of patients with chronic tonsillitis and 29 cases of healthy controls. The results obtained were as follows; 1) Serum Ig M level was significantly higher in patient group than in control group but was not significantly different preoperative from postoperative patient group. 2) Population of T-lymphocyte more significantly decreased in patient group than in control group but it was not significantly different preoperative from postoperative patient group. 3) Population of B-lymphocyte more significiantly increased in patient group than in control group but it was not significantly different preoperative from postoperative patient group. On the basis of these results, it may be suggested that tonsil play partially a role in the immune response of human.

• Korean Journal of Microbiology
• /
• v.49 no.2
• /
• pp.105-111
• /
• 2013

The Erm family of adenine-$N^6$ methyltransferases (MTases) is responsible for the development of resistance to macrolide-lincosamide-streptogramin B antibiotics through the methylation of 23S ribosomal RNA. Recently, it has been proposed that well conserved amino acids in ErnC' located in concave cleft between N-terminal 'catalytic' domain and C-terminal 'RNA-binding' domain interacts with substrate RNA. We carried out the site-directed mutagenesis and studied the function of the ErmSF R237 mutant in vitro and in vivo. R237 amino acid residue is located in the concave cleft between two domains. Furthermore this residue is very highly conserved in almost all the Erm family. Purified mutant protein exhibited only 51% enzyme activity compared to wild-type. Escherichia coli with R237A mutant protein compared to the wild-type protein expressing E. coli did not show any difference in its MIC (minimal inhibitory concentration) suggesting that even with lowered enzyme activity, mutant protein was able to efficiently methylate 23S rRNA to confer the resistance on E. coli expressing this protein. But this observation strongly suggests that R237 of ErmSF probably interacts with substrate RNA affecting enzyme activity significantly.

• Applied Microscopy
• /
• v.32 no.4
• /
• pp.329-337
• /
• 2002

The morphology and cellular characteristics of adventitious roots, viz aerial roots, in the epiphytic American Ivy were examined to reveal structural changes of the aerial root upon surface attachment. Immature aerial roots were composed of parenchyma cells with dense cytoplasm containing plastids, however, the upper and lower epidermis were not distinguished. At early development, electron-dense substances (EDS) were constituents of much of the aerial root tissue, but the distribution of EDS varied within the tissue. The deposits appeared most concentrated in the superficial cell layers, with lesser amounts in cell layers closer to the cortex. Electron micrographs revealed that EDS deposits were always found in the vacuole, and were mainly associated with the tonoplast. While most of them occurred in the vacuole as small spherical deposits adjacent to the tonoplast, some deposits were oddly shaped or larger in size. Many of the vacuoles eventually filled with EDS, but the EDS content in those vacuoles decreased substantially after initial attachment to the surface. When the vacuoles became almost empty, cells near the epidermis already exhibited irregularity in outline. Subsequent breakdown of cellular components took place in the cells while they were still attached to the surface. This study suggests the potential role of EDS as substances involved in the surface attachment of the plant, however, further studies must be conducted to reveal the nature of EDS and the effects of EDS storage within these vacuoles.

• Korean Journal of Food Science and Technology
• /
• v.39 no.1
• /
• pp.7-13
• /
• 2007

The changes in phenolic compounds and pectin content were investigated during the growth of 3 cultivars (Hosui, Niitaka and Chuwhangbae) of Asian pear (Pyrus pyrifolria) fruits. The amounts of total phenolic compounds in peel, flesh and core was 20.61-22.98mg/g, 0.87-1.23mg/g and 6.39-37.96mg/g during early growth, respectively, and decreased with pear growth. Arbutin, chlorogenic acid and epicatechin were detected in each part of all three cultivars during early growth; of these, arbutin content was the highest. Caffeic acid, catechin and 4-hydroxymethyl benzoic acid were detected in the peel and core during the ripening process. The total pectin content in the flesh of Hosui, Niitaka, and Chuwhangbae cultivars decreased from 5.93mg/g, 5.99mg/g and 5.40mg/g to 1.07mg/g, 1.60mg/g and 1.63mg/g, respectively. Of the soluble pectins, the hydrochloric acid-soluble pectin content was the highest, 3.21-3.45mg/g, and decreased during growth.

• Korean Journal of Microbiology
• /
• v.52 no.4
• /
• pp.487-494
• /
• 2016

In Saccharomyces cerevisiae, Paf1 complex consists of five proteins, and they are structurally and functionally well conserved in yeast, fruit fly, plants, and human. With binding to RNA polymerase II from transcription start site to termination site, Paf1 complex functions as a platform for recruiting many types of transcription factors to RNA polymerase II. Paf1 complex contributes to H2B ubiquitination and indirectly influences on H3K4 di- and tri-methylation by histone crosstalk. But the individual effects of five components in Paf1 complex on these two histone modifications including H2B ubiquitination and H3K4 methylation largely remained to be identified. In this study, we constructed the single-gene knockout mutants of each Paf1 complex component and observed H3K4 mono-, di-, and trimethylation as well as H2B ubiquitination in these mutants. Interestingly, in each ${\Delta}paf1$, ${\Delta}rtf1$, and ${\Delta}ctr9$ strain, we observed the dramatic defect in H3K4 monomethylation, which is independent of H2B ubiquitination, as well as H3K4 di- and trimethylation. However, the protein level of Set1, which is methyltransferase for H3K4, was not changed in these mutants. This suggests that Paf1 complex may directly influence on H3K4 methylation by directly regulating the activity of Set1 or the stability of Set1 complex in an H2B ubiquitination independent manner.