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        • KCI등재후보

          Performance Evaluation of an Electrometer for Quality Control and Dosimetry in Radiation Therapy

          Kim, Chang-Seon,Kim, Chul-Yong,Park, Myung-Sun Korean Society of Medical Physics 2000 의학물리 Vol.11 No.2

          전리계의 성능은 방사선 선량측정의 정확도와 정밀도에 직접적으로 영향을 준다. 본 연구에서는 전리계의 성능을 유지하기 위한 정도관리의 항목들을 제시하고 구체적인 성능검사를 시행하고자 한다. 선정된 성능평가 항목들은 적절한 인가전압, 예열 및 고전압 후의 평형시간, 누설에 의한 상쇄 전류, 방사선 측정 전후의 영점이동 (배경전류), 장시간 안정성, 선형성, 외부조건의 영향 등이었다. 전리계에 연결된 자루가 단단한 전리함과 방사선원으로 스트론티움-90이 내장된 검사기가 성능검사용으로 이용되었다. 인가전압의 측정은 전리함의 입력단자에서 직접 측정하였고 평형시간의 측정은 전리계에 전원을 연결한 후와 인가전압을 바꾼 후 검사기에 연결된 전리함의 반응이 안정을 가져오는 시간으로 측정하였다. 누설은 전리계가 안정된 후 방사선을 조사하지 않은 상태에서 전리계의 측정값이 영점에서 이동하는 것으로 나타냈으며 배경전류는 안정된 전리계의 영점을 조정하고 전리계에 연결된 검사기에서 전리함을 10분 조사한 후 영점의 변화로 나타냈다. 장시간의 안정성 3개월에 걸쳐 측정되었으며 이때 검사기의 측정값을 온도-기압에 대한 보정을 한 후 그 값을 비교하였다. 선형성은 전리계에 연결된 전리함을 n번 연속하여 조사하여 그 전체의 측정값과 초기값을 n번 곱한 값을 비교하였다. 외부조건의 영향은 인위적으로 외부온도를 17-34 $^{\circ}C$ 로 변화시켜서 환경변화에 의한 전리계의 영점이동으로 나타냈다. 인가전압의 측정에서 명목상의 인가전압 300, 500V에 대한 측정값은 각각 2.5%와 5.8% 작게 나타났다. 전원을 연결한 후 전리계가 실제로 평형에 도달하는 시간은 20분으로 이는 전리계의 안정성 표시기보다 9분 지연되었으며 인가전압을 바꾼 경우에는 1분 이내에 평형에 도달하였다. 전리계의 누설의 측정에서 영점의 이동은 0.002(스케일)/15분이었고 10분 조사 후 영점의 이동은 발견되지 않았다. 전리계는 3개월 동안 99.4%의 안정성을 유지하였다. 스케일 영역 0.000-9.991 에서 전리계의 선형성에서의 이탈은 0.9% 이었다. 온도 범위 17 - 34 $^{\circ}C$ 에서 전리계의 영점이동은 0.2% 이내였다. 본 연구에서는 임상에서 사용하고 있는 전리계에 대한 성능을 평가하는 항목을 제시하고 이를 전리계의 정도관리에 이용하도록 하였다. 이러한 프로그램의 운용을 통하여 전리계에 의한 오차를 줄임으로써 방사선측정에서의 정확도와 정밀도를 향상시킬 수 있을 것으로 사료된다. The performance of an electrometer directly affects on the accuracy and precision in radiation dosimetry. This study is to list of the quality control for maintaining performance and to perform evaluation tests of an electrometer. Performance tests selected include proper polarizing voltages, warm-up and equalization time, leakages, long-term stability, linearity, and effect of ambient conditions. An electrometer connected with a rigid stem ionization chamber was evaluated with a Strontium-90 check device. Bias voltage was measured directly on the input socket. Equalization time is the time required for reaching threshold of charged state after the power is on or the bias voltage is changed. Pre- and post-signal leakages are defined as the accumulation of signal with no exposure and after exposure, respectively. Over three months period, the electrometer's long-term stability was measured by comparison of the temperature-pressure corrected readings. Linearity was expressed as the deviation of readings from multiple short exposures from one continuous exposure. Effect of ambient conditions was expressed as the zero drift of the electrometer over 17-34$^{\circ}C$ temperature ranges. For two nominal values, 300 and 500 volts, measured voltages were lower by 2.5 and 5.8%, respectively. The warm-up time, 20 minutes, was longer than the lamp time by 9 minutes and the equalization time was less than 1 minute. Without exposure, the zero-drift was 0.002 scale-unit in 15 minutes and the leakage after 10 minutes exposure was minimal. The IQ-4 was stable over 99.4% for three-month periods. Deviation from the linearity was 0.9% for measurement scale, 0.000-9.991. Over 17-34$^{\circ}C$ temperature range, the zero-drift was minimal, less than 0.2%. For a clinically-used electrometer, a list for the basic peformance evaluations is proposed. By running this program, the measurement error using an electrometer can be reduced and in turn the improvement in accuracy and precision of radiation dosimetry can be achieved.

        • KCI등재후보

          5, 7-DHT가 흰쥐 등쪽솔기핵내 신경아교세포에 미치는 영향

          채제명(Je Myung Chae),조승묵(Seung Mook Jo),남성안(Seong Ahn Nam),윤상선(Sang Seon Yoon),고병문(Byung Moon Ko),최창도(Chang Do Choi),최월봉(Wol Bong Choi) 대한해부학회 1998 Anatomy & Cell Biology Vol.31 No.1

          '스콜라' 이용 시 소속기관이 구독 중이 아닌 경우, 오후 4시부터 익일 오전 7시까지 원문보기가 가능합니다.

          신경독성물질인 5, 7-dihydroxytryptamine (5, 7-DHT)이 중추신경계통내 serotonin 신경세포에 미치는 영향과 이에 따른 신경아교세포들의 반응을 형태학적으로 규명하고자 본 연구를 시행하였다. 흰쥐의 가쪽뇌실에 5, 7-DHT(200μg)를 투여한 후면역세포화학적 염색을 시행한 후 광학 및 전자현미경하에서 등쪽솔기핵내 serotonin 신경세포에 초래되는 퇴행성변화와 주위 신경아교세포들의 반응양상 등을 경시적으로 (1, 3, 5, 10 및 20일) 관찰하였던 바 아래와 같은 결과를 얻었다. 흰쥐 등쪽솔기핵내 5, 7-DHT의 세포독성에 반응을 보인 신경아교세포로는 미세아교세포와 별아교세포였으며, 이들 세포 들의 반응양상은 매우 특징적이었으며, 상당한 차이를 보였으며, 전반적으로 미세아교세포가 별아교세포에 비해 빠른 변화소견을 보였다. 즉, 미세아교세포의 경우 실험 3일군 및 5일군에서 이미 그 수의 증가와 함께 활발한 포식작용을 보였던 반면, 별아교세포는 후기 실험군인 10일군 및 20일군에 이르러서야 세포질의 비대 및 수적 증식을 통하여 손상된 신경조직을 보상할 뿐 아니라 밀집된 미세아교세포들을 분산시키는 소견이 관찰되었다. 그러나 희소돌기아교세포는 본 연구의 전 실험군을 통하여 특별한 변화소견이 관찰되지 않았다. 이상의 결과로 부터 5, 7-DHT가 흰쥐 등쪽솔기핵내 신경세포에 강한 세포독성을 유발하며, 이에 따른 주위 신경아교세 포들 특히 미세아교세포와 별아교세포는 시간경과에 따라 매우 다양한 반응양상을 보인다는 사실을 알게 되었다 This study was designed to clarify the cytotoxic effects of 5, 7-dihydroxytryptamine (5, 7-DHT) on the serotonergic neurons in the dorsal raphe nucleus, and to investigate the glial reaction during the neurodegenerative changes by light and electron microscopy. Adult male rats (Sprague-Dawley strain) weighing from 250 g to 350 g each were used as experimental animal. 5, 7-DHT(200 μg dissolved in 0.9% NaCl) was injected into the lateral ventricle of the rat brain with the Hamiton syringe fixed on stereotaxic apparatus. The control rats were given with the similar volume of 0.9% NaCl. The rats were sacrified on the 1st, 3rd, 5th, 10th and 20th day after the injection of 5, 7-DHT. The results were as follows : Glial reactions induced by 5, 7-DHT were also observed in DRN. In early experimental stage, microglial reactions prevailed, whereas astroglial reactions were prevailing in later stage. In addition, microglial cells phagocytosed and removed the degenerated cells. However, astrocytes in DRN did not show phagocytotic activities such as microglial cells. Based on the results, author thought that 5, 7-DHT act as a specific neurotoxin to serotonergic neurons in DRN, and induces severe neurodegenerative changes. The glial reactions in DRN are activated during the neurodegerative changes, and show characteristic patterns of glial reactions.

        • KCI등재

          최소자승법을 이용한 다수 베타 방출 핵종 혼합물의 방사능 분석

          선광일,남욱원,공경남,김창규,이동명,이상국 대한방사선 방어학회 2001 방사선방어학회지 Vol.26 No.4

          베타선 스펙트럼의 최대 에너지가 확실하게 구별되는 2개의 핵종만을 포함하는 혼합시료의 경우에는 최대 에너지가 다르다는 점을 이용하여 손쉽게 각 핵종의 방사능값을 측정할 수 있다. 그러나 3개 이상의 베타 방출 핵종이 포함된 혼합물에 대해서는 각 핵종의 스펙트럼이 서로 겹치기 때문에 이러한 방법으로 구해진 방사능값은 신뢰도가 떨어지게 된다. 따라서, 본 연구에서는 최소자승법을 이용하여 혼합물의 중첩된 베타선 스펙트럼을 각각 분리 정량분석할 수 있는 밥법을 제시하였다. 또한, 실제로 4개의 베타 방출 핵종 ^3H, ^14C, ^16Cl, 90Sr)이 혼합된 사료를 조제하여 본 분석법을 검증한 결과 최고치 Reference value)와 분석치가 7% 이내에서 잘 일치함을 보였다. It is possible to count and perform quench correction on two β-label samples so long as the maximum β-energies are sufficiently different. However, when the coventional technique is applied to the radioassay of a mixture of more than three nuclides, the reliability of the activiteis determined is considerably reduced, resulting from the large overlapping of liquid scintillation pulse height distributions of ezch nuclide. A technique that allows the activities of multiple β-labeled samples to be radioassayed was proposed by using the least square method. The technique was applied to mixture samples of ^3H, ^14C, ^16Cl, and ^90Sr. The analytical values were in good agreement with the reference values within 7% relstive error.

        • 심혈관계 질환 유전자 치료

          명창선 충남대학교 약학대학 의약품개발연구소 2008 藥學論文集 Vol.23 No.-

          On the basis of developing knowledges in molecular and cellular cardiology, cardiac gene therapy has already been investigated and approved for cardiovascular diseases in animal studies. Studies for cardiac gene therapy have developed different gene-delivering vector systems. Non-viral vector systems such as plasmid DNA allow remarkable organ specificity, however, they are often limited by low transfection efficiency and transient gene expression. Viral vector systems allow high transfection efficiency, however, they are low organ-specific and limited to use owing to their immunogenicities. Recently, using advanced transcriptional and transductional targeting strategies, viral vectors have been improved and, moreover, more efficient serotypes of adeno-associated viruses(AAV) have been identified that show increased transduction rates, thus reducing the necessity for high virus titers. Many other modified vectors are being developed to overcome the obstacles of gene therapy. This review article will give a broad overview of the technical aspects of cardiovascular gene therapy including viral/non-viral vectors, a control of endothelium cell function, smooth muscle cell inhibition, therapeutic angiogenesis, modification of progenitor cells, and tissue engineered vascular conduits, and will discuss clinical trials and direction of future studies.

        • Purge & Trap-GC를 이용한 의약품 필름코팅 정제 중 잔류용제에 관한 연구

          장준식,이명자,소유섭,문춘선,이주헌,박희라,김진숙,강경모,이선옥,방성연,유미자,유문균,금오성,이병욱 식품의약품안전청 2000 식품의약품안전청 연보 Vol.4 No.-

          의약품은 약물을 생체에 적풋하기 위하여 유효성분의 효과가 언제나 일정하게 확보되고 사응에 편리하도록 만들어지는 것이므로 유효썽분 이외에 약효에 영향을 주지 않는 성분이 첨가되는 경운가 많다. 이 때 사용되는 용매들은 제피의 광택 및 건쪼시간의 단축 등을 위하여 휘발점이 낮을 용매들이 주로 사용되어진다. 본 연구는 의약품 필름코팅정제 중 잔류용매 4종(chlorofonr benzen, trichloro ethylen, 1,4-dioxane)에 대한 변형된 pirge & trap-GC 장치를 이용한 동시분석방법을 개발하였으며, 각 표준품의 RSD 값은 chloroform 3.03%, benzen 3.17%, trichloroethylen 3.69% and 1,4-dioxane 3.41%였다. 또한 시중 유통중인 의약품 50종에 대하여 잔류웅매 양을 측정하였으며, 검출되는 잔류용매는 한 건도 없었다. This study nras carried out to develope the analytical method for the mixture of chlorefonn, benzen, trichloroethylen and 1,4-dioxane simultaneously and determine the remainingorgauic solvents in coating tablets by Purge & Trap-GC. The results were as follouFs ; 1. Chloroform, benzen, trio:tloroethylen and 1,4-dioxane separated by tenax #5 trap by HP-624GC column by terrlperature programming. The peaks were separated completely at retentiontime of 6.88min for chloroform, 8.21min for benzen, 10.38miu for trichloroethylen and 11.95minfor 1,4-dioxane. 2. Standard RSD were individually chloroform 3.03%, benzen 3.17%, trichloroethylen 3.69%and 1,4-diorane 3.41%. 3. 60 samples were not detrcted chloroform, benzen, trichloroethylen and 1,4-dioxane.

        • Irbesartan과 Amlodipine의 병용투여에 의한 혈관 손상 보호 효과

          한주희,명창선 충남대학교 약학대학 의약품개발연구소 2012 藥學論文集 Vol.27 No.-

          The protective effects of irbesartan and amlodipine on neointimal hyperplasia have been well characterized. However, little is known about the beneficial effects of combination therapy of these two drugs for the protection of neointimal hyperplasia. This study was designed to investigate the synergistic effect of irbesartan combined with amlodipine on the magnitude of protective action in vascular injury mediated by cuff-induced neointimal hyperplasia model in spontaneous hypertensive rats. Irbesartan at 1.53 mg/kg (p.o.) or amlodipine at 0.48 mg/kg (p.o.) significantly decreased BrdU-positive cells in neointima, indicating the inhibition of cell proliferation including a progress of DNA synthesis. The combined treatment of same doses of irbesartan with amlodipine significantly decreased in BrdU incorporation. Interaction index calculated by isobolar method indicated that the combination therapy of these two drugs were synergistic. Therefore, these results suggest that the combined therapy of irbesartan with amlodipine be fully effective for the treatment of vascular remodeling such as restenosis.

        • Valsartan과 Amlodipine의 병용투여에 의한 혈압하강 상승 및 혈관손상 보호효과

          한주희,명창선 충남대학교 약학대학 의약품개발연구소 2013 藥學論文集 Vol.28 No.-

          This study was aimed to investigate the synergistic effect of valsartan combined with amlodipine on the anti-hypertensive effect and protective action in vascular injury mediated by cuff-induced neointimal formation model in vivo. For the measurement of blood pressure, spontaneous hypertensive rats (SHRs) were given in that random orders valsartan 0, 7.65, 15.3 mg/kg, amlodipine 0, 0.48, 0.96 mg/kg, or the higher/lower doses in combination. For the measurement of neointimal hyperplasia, 15.3 mg/kg of valsartan or 0.96 mg/kg of amlodipine in alone or combination were given for 2 weeks to cuffed C57BL/6 mice. The results showed that the combination therapy of high doses of valsartan and amlodipine significantly decreased in systolic blood pressure (SBP) and mean arterial pressure (MAP) as compared with monotherapy of each drug, but not in combined therapy of low doses of two drugs. In protection for vascular remodeling, valsartan 15.3 mg/kg and amlodipine 0.96 mg/kg in combination significantly decreased BrdU-positive cells in neointima and [3H]-thymidine, indicating the inhibition of cell proliferation including a progress of DNA synthesis comparing to respective effects. Therefore, present study implies that combination of valsartan and amlodipine may be fully effective for the treatment of hypertension and vascular remodeling.

        • 선천성 고혈압 쥐에서 Irbesartan과 Lisinopril의 병용 투여에 의한 혈압하강 상승효과

          이상길,명창선 충남대학교 약학대학 의약품개발연구소 2013 藥學論文集 Vol.28 No.-

          Both irbesartan, one of the angiotensin II receptor blocker (ARB), and lisinopril, a angiotensin-converting enzyme inhibitor (ACEI), are using for the treatment of hypertension. The aim of this study was to examine the drug synergism of combined treatment of irbesartan with lisinopril in blood pressure (BP)-lowering effect. Each telemetered-spontaneous hypertensive rat (SHR) was orally received all seven treatments once with an interval of several days between each injection for washing-out and return to high BP levels and BP was monitored control (vehicle-treated), irbesartan (7.18 mg/kg/day as low-dose; 28.74 mg/kg/day as high-dose), lisinopril (0.48 mg/kg/day as low-dose; 1.92 mg/kg/day as high-dose), and low-dose or high-dose combination of irbesartan with lisinopril. The results showed that only high-dose combination of irbesartan and lisinopril exerts significant additive BP-lowering effect as compared with high-dose monotheraphy of each drug. The present study implies that drug combination of irbesartan with lisinopril can offer a clinically effective tool for treating hypertension.

        • 비-바이러스성 유전자 전달

          박준원,명창선 충남대학교 약학대학 의약품개발연구소 2009 藥學論文集 Vol.24 No.-

          The specific aim of gene therapy is to deliver a therapeutic target gene to cells in where the expression of transgene can be properly increased. Two main types to deliver a transgene are using viral vectors or nonviral approaches. Gene delivery using viral vectors shows long-term gene expression with high efficiency. However, since the issues about safety and the limitation of transgene size in recombinant viruses, nonviral approaches have been practically challenged. Nonviral approches can be divided two approaches; physical and chemical ones. In this review, the most commonly used nonviral methods were discussed with its mechanism of action for gene delivery. Moreover, the technical aspects of each delivery system were reviewed with their advantages and limitations for practical applications. Although the progress in vector design and the understanding of transfection biology has been remarkably made, continuous effort to improve currently available systems is needed for safer and more efficient nonvial gene delivery.

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