• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.60-61
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• 2003

A new approach to reduce the computation time of genetic algorithm (GA) for making binary phase holograms is described. Synthesized holograms having diffraction efficiency of 75.8% and uniformity of 5.8% are proven in computer simulation and experimentally demonstrated. Recently, computer-generated holograms (CGHs) having high diffraction efficiency and flexibility of design have been widely developed in many applications such as optical information processing, optical computing, optical interconnection, etc. Among proposed optimization methods, GA has become popular due to its capability of reaching nearly global. However, there exits a drawback to consider when we use the genetic algorithm. It is the large amount of computation time to construct desired holograms. One of the major reasons that the GA' s operation may be time intensive results from the expense of computing the cost function that must Fourier transform the parameters encoded on the hologram into the fitness value. In trying to remedy this drawback, Artificial Neural Network (ANN) has been put forward, allowing CGHs to be created easily and quickly (1), but the quality of reconstructed images is not high enough to use in applications of high preciseness. For that, we are in attempt to find a new approach of combiningthe good properties and performance of both the GA and ANN to make CGHs of high diffraction efficiency in a short time. The optimization of CGH using the genetic algorithm is merely a process of iteration, including selection, crossover, and mutation operators [2]. It is worth noting that the evaluation of the cost function with the aim of selecting better holograms plays an important role in the implementation of the GA. However, this evaluation process wastes much time for Fourier transforming the encoded parameters on the hologram into the value to be solved. Depending on the speed of computer, this process can even last up to ten minutes. It will be more effective if instead of merely generating random holograms in the initial process, a set of approximately desired holograms is employed. By doing so, the initial population will contain less trial holograms equivalent to the reduction of the computation time of GA's. Accordingly, a hybrid algorithm that utilizes a trained neural network to initiate the GA's procedure is proposed. Consequently, the initial population contains less random holograms and is compensated by approximately desired holograms. Figure 1 is the flowchart of the hybrid algorithm in comparison with the classical GA. The procedure of synthesizing a hologram on computer is divided into two steps. First the simulation of holograms based on ANN method [1] to acquire approximately desired holograms is carried. With a teaching data set of 9 characters obtained from the classical GA, the number of layer is 3, the number of hidden node is 100, learning rate is 0.3, and momentum is 0.5, the artificial neural network trained enables us to attain the approximately desired holograms, which are fairly good agreement with what we suggested in the theory. The second step, effect of several parameters on the operation of the hybrid algorithm is investigated. In principle, the operation of the hybrid algorithm and GA are the same except the modification of the initial step. Hence, the verified results in Ref [2] of the parameters such as the probability of crossover and mutation, the tournament size, and the crossover block size are remained unchanged, beside of the reduced population size. The reconstructed image of 76.4% diffraction efficiency and 5.4% uniformity is achieved when the population size is 30, the iteration number is 2000, the probability of crossover is 0.75, and the probability of mutation is 0.001. A comparison between the hybrid algorithm and GA in term of diffraction efficiency and computation time is also evaluated as shown in Fig. 2. With a 66.7% reduction in computation time and a 2% increase in diffraction efficiency compared to the GA method, the hybrid algorithm demonstrates its efficient performance. In the optical experiment, the phase holograms were displayed on a programmable phase modulator (model XGA). Figures 3 are pictures of diffracted patterns of the letter "0" from the holograms generated using the hybrid algorithm. Diffraction efficiency of 75.8% and uniformity of 5.8% are measured. We see that the simulation and experiment results are fairly good agreement with each other. In this paper, Genetic Algorithm and Neural Network have been successfully combined in designing CGHs. This method gives a significant reduction in computation time compared to the GA method while still allowing holograms of high diffraction efficiency and uniformity to be achieved. This work was supported by No.mOl-2001-000-00324-0 (2002)) from the Korea Science & Engineering Foundation.

• Journal of Gastric Cancer
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• 제6권3호
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• pp.146-153
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• 2006

목적: 본 연구에서 수술로 절제된 위의 위장관 간질 종양 (GISTs)환자들의 임상적 특징과 치료방법 및 예후에 영향을 미치는 인자들을 밝혀보고자 하였다. 대상 및 방법: 1992년부터 2002년까지 가톨릭대학교 의과대학 외과학 교실에서 GISTs로 진단 받고 수술을 시행한 환자의 파라핀 포매조직을 이용하여 CD117 (c-kit) 면역조직화학염색상 확진된 76명의 환자를 대상으로 하였다. 이들의 나이, 성별, 위치, 크기, 세포분열지수을 파악하고 Ki67, p53 면역화학 염색을 시행하였으며 c-kit 유전자의 변이 여부를 확인한 후 이들 인자의 예후인자로서의 가치를 평가하였다. 결과: 대상 환자 76명의 평균 나이는 55.9세였으며 남자가 34명이었고 여자는 42명 이었다. 평균 추적검사 기간은 42개월이었다. 환자들은 복통(27명, 36%)과 출혈(20명, 26%)을 주소로 내원한 경우가 가장 많았으며 위의 상부 1/3에 종양이 위치한 경우가 47명(62%)으로 가장 많았고 수술방법은 종양의 위치보다는 크기와 유의한 관계를 보였다(P<0.05). GISTs 분류상 고위험군에 해당하는 환자군이 중등도 위험군과 저위험도군에 비하여 의미있게 무병기간이 짧았고(P=0.05) 종양의 크기가 5 cm 이상 큰 경우(P=0.017), 유사분열의 수가 5/50 HPF 이상 많은 경우(P=0.042) 그리고 Ki67 과발현된 경우(P=0.046), c-kit 유전자의 변이를 보이는 경우(P=0.037)가 예후가 좋지 않았다. 결론: 종양의 크기가 5 cm 이상 큰 경우, 유사분열의 수가 5/50 HPF 이상 많은 경우 그리고 Ki67이 과발현된 경우와 c-kit 유전자의 변이를 보이는 경우가 환자의 예후에 좋지 않은 영향을 미치는 인자였다. 이런 예후 인자를 보이는 환자들에 있어서 수술 후 추적검사 과정에 있어서 보다 세심한 관찰이 필요하겠다. 예후와는 관련이 없었다.27^{kip1}$도 다른 인자에서는 통계적인 유의성이 없었다. 의 상관관계는 $p21^{Waf1/Cip1}(+)$과 $p27^{kip1}$의 상관관계는 $p21^{Waf1/Cip1}(+)/p27^{kip1}(+)$ 보이는 경우(53.3%)와, $p21^{Waf1/Cip1}(-)/p27^{kip1}(-)$ 보이는 경우(76.5%)가 많았다(P<0.05). $p21^{Waf1/Cip1}$과 $p27^{kip1}$ 복합 검사에서는 $p21^{Waf1/Cip1}(+)/p27^{kip1}(+)$인 경우에 T1-2 (87.5%)가 많았고 $p21^{Waf1/Cip1}(-)/p27^{kip1}(-)$인 경우에는 T3-4(58.1%)가 많았다(P<0.05). 또한 Lauren 분류에서는 $p21^{Waf1/Cip1}(+)/p27^{kip1}$인 경우가 장형 (100%)에서만 나타났으며(P<0.05), $p21^{Waf1/Cip1}(-)/p27^{kip1}(-)$인 경우는 미만형인 경우(87.0%)가 장형(54.9%)의 경우보다 많은 비율을 차지하였다(P<0.05). 5년 장기 생존율에 있어서는 각각의 $p21^{Waf1/Cip1}$과$p27^{kip1}$의 발현 유무에 따른 통계적인 유의성은 없었고 복합 검사에서도 $p21^{Waf1/Cip1}(+)/p27^{kip1}(+)$의 경우에 생존율이 높았지만 통계적인 유의성은 없었다. 결론: 저자들의 경우에는 $p21^{Waf1/Cip1}$과$p27^{kip1}$은 서로 비슷한 발현 형태를

• 미생물학회지
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• 제41권3호
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• pp.177-182
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• 2005

본 연구를 수행하기 전에 H. pylori에 대한 어떠한 치료도 받지 않은 114명의 소화기 궤양 환자들을 내시경 검사를 하는 동안, 114개의 H. pylori 균주를 위 전정부로부터 분리하였다. H. pylori를 검출하기 위하여 rapid urease test, SSA와 cagA 유전자의 PCR증폭을 수행하였고, CagA 발현 검출을 위하여 Western blot을 수행하였다. H. pylori에 감염된 환자들은 omeprazole. clarithromycin (a macrolide), amoxicillin을 모두 사용하는데 3제 요법(triple therapy)으로 치료하였다. 치료가 중단되고 6주 후에 내시경 검사에서 세균 박멸률을 측정하였다. 내성률은 각각 clarithromycin이 $20.2\%$. amoxicillin이 $0.0\%$였다. Clarithromycin 내성은 H. pylori의 23S rRNA 유전자에 있는 A2142G돌연변이에 의한 것이 $87\%$이었다. A2142G돌연변이의 clarithromycin의 MIC값($32\~>256\;{\mu}g\ml$)은 A2143G돌연변이의 MIC값($4\~128\;{\mu}g/ml$)보다 더 높았다. Clarithromycin에 감수성을 가진 H. pylori는 박멸되었으나 clarithromycin내성을 가진 H. pylori는 박멸되지 않았다(P = 0.0001). 이러한 결과들은 CagA 발현에는 어떠한 영향도 받지 않았으며 H. pylori의 clarithromycin 내성은 치료 실패의 가장 중요한 이유임을 제시하였다. 우선적으로 실시되는 생검 배양에 대한 H. pylori의 항생제 감수성 시험은 감염된 환자들에 대한 3제 요법을 선택하기 이전에 필히 실시되어야 하며 국내에서 clarithromycin에 대한 1차 내성의 높은 빈도는 H. pylori의 감염증 치료에 심각한 문제점을 야기시켰다.

• 한국물환경학회지
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• 제21권5호
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• pp.484-489
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• 2005

In order to determine the removal rate of non-biodegradable substances and the change of their structural properties, this study was carried out by an ozone-treatment experiment on leachate collected from the landfill area of D City in Chung chung nam-do and examined the change of the chemical properties of non-biodegradable substances. The main elements of non-biodegradable substances in landfill leachate were benzene, toluene, trichloroethane, trichloroethylene, xylene, etc. and the concentration of toluene was 15.7 mg/L on the average, benzene 7.2 mg/L, trichloroethane 1.1 mg/L, trichloroethylene 0.75 mg/L and xylene 0.5 mg/L. When leachate was treated with ozone for 10 min, 30 min and 60 min, UV absorbance was reduced with the increase of reaction time, and the reduction rate was 38.6% at 60 min. TOC was removed by 13.2% at 60 min. The low reduction rate of TOC may be because TOC reacts indirectly with OH radical produced from reaction with ozone while UV absorbance usually relies on direct reaction between organic matters and ozone molecules. Color was removed by up to 97%, which suggests that ozonation is highly effective in removing coloring elements in leachate. Sixteen kinds of non-biodegradable compounds were found in the leachate and most of them had the characteristic of aromatic hydrocarbon. Among them dibutyl phthalate was identical with a substance included in the list of US EPA, which is classified as a mutagen that may cause the mutation of genes and disorders in chromosomes. In addition, 2,5-Cyclohexadiene-1,4-dione, 1,2-Benzenedicarboxylic acid and butyl octyl ester were found to be similar to substances listed by USEPA. According to the result of analyzing structural changes before and after ozonation using GC-MS, cyclic compounds and aromatic compounds were observed in the original water and aliphatic compounds were newly observed after ozonation. In addition, through ozonation, humic substances of high molecular weight were oxidized and decomposed and produced low-molecular compounds such as aldehyde, ketone and carboxyl acid and highly biodegradable aliphatic carbon, which suggests the bio-degradability of non-biodegradable substances.

• 미생물학회지
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• 제54권3호
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• pp.200-207
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• 2018

높은 염분 농도에서 glycine betaine은 Bacillus subtilis 안으로 유입되어 세포 생장이 지속될 수 있게 한다. 뿐만 아니라 최근 연구 결과에 따르면 저온에서도 glycine betaine이 세포 생장을 지속시키는 것으로 알려져 있다. 저온에서 Bacillus subtilis의 생장을 저해시키는 세포 대사 활동으로는 세포막 운송과 단백질 합성을 들 수 있다. 세포막 구조와 관련하여 저온에서 세포막 운송에 영향을 주는 유전자들로는 bkdR과 des가 있고, 단백질 합성 과정에서 RNA helicase 유전자인 ydbR과 yqfR들은 저온 민감성을 보인다. 따라서 Bacillus subtilis 저온 민감성 유전자 결손 세포들에 대한 glycine betaine의 효과를 조사하여 저온에서의 glycine betaine 생리적 기능에 대해 알아보고자 하였다. 이 결과 glycine betaine의 존재 유무에 따라 야생형 Bacillus subtilis와 ydbR과 yqfR 결손 균주의 저온생장에 큰 차이를 보였다($T_d$차이 190~686 min). 반면에 bkdR이나 des 결손균주의 경우에는 glycine betaine 존재 유무에 따라 차이를 보이지 않았다. Glycine betaine의 전구체인 choline으로 대치하여도 저온에서의 생장은 같은 결과를 보였다. Glycine betaine의 영향이 세포막 구조와 관련이 있는 유전자 bkdR과 des 결손균주에 미치는 영향이 적은 것을 알아보기 위해 세포막에 영향을 주는 세제의 효과를 조사하였다. Triton X-100과 N-lauryl sarcosine 세제에 의해 bkdR 결손 균주가 야생형에 비해 더 영향 받는 것을 확인하였고 이는 bkdR 결손이 저온에서 막 구조를 변형하여 glycine betaine의 투과에 영향을 미치는 것으로 보인다.

• 대한세포병리학회지
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• 제7권2호
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• pp.144-150
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• 1996

Although bladder cancers are very common, little is known about their molecular pathogenesis. It is known that p53 alteration is found in about 60% of muscle-invasive bladder cancer, necessiating aggressive therapy and poor outcome. We examined the nuclear expression of p53 protein, using D07 monoclonal antibody in the urine samples from 31 patients with transitional cell carcinoma of the bladder to investigate the correlation of p53 overexpression with histologic grades and depth of invasion. The positive rate of p53 protein was 27% in superficial bladder tumor, but increased up to 71% in the invasive bladder carcinomas. The overexpression of p53 protein increased according to Mostofi grading system from 18% in grade I, 45% in grade II, and up to 100% in grade III. The p53 expression tended to be higher in the invasive and high grade bladder cancers than in the superficial and low grade ones(p<0.05). These results suggest that immunohistochemical analysis of the urine specimen in the bladder cancer patients could be a useful method of screening for the presence of p53 mutant protein. The mutant p53 protein expression may be an indicator of bladder cancer with more proliferative potential and/or aggressive biologic behavior.

• 환경생물
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• 제28권2호
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• pp.101-107
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• 2010

Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. Ionizing radiation (IR) is an active tool for destruction of cancer cells and diagnosis of diseases, etc. IR induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm and nucleus. Yeasts have been a commonly used material in biological research. In yeasts, the physiological response to changing environmental conditions is controlled by the cell types. Growth rate, mutation and environmental conditions affect cell size and shape distributions. In this work, the effect of IR and mercury chloride (II) on the morphology of yeast cells were investigated. Saccharomyces cerevisiae cells were treated with IR, mercury chloride (II) and IR combined with mercury chloride (II). Non-treated cells were used as a control group. Morphological changes were observed by a scanning electron microscope (SEM). The half-lethal condition from the previous experimental results was used to the IR combined with mercury. Yeast cells were exposed to 400 and 800 Gy at dose rates of 400Gy $hr^{-1}$ or 800 Gy $hr^{-1}$, respectively. Yeast cells were treated with 0.05 to 0.15 mM mercury chloride (II). Oxidative stress can damage cellular membranes through a lipidic peroxidation. This effect was detected in this work, after treatment of IR and mercury chloride (II). The cell morphology was modified more at high doses of IR and high concentrations of mercury chloride(II). IR and mercury chloride (II) were of the oxidative stress. Cell morphology was modified differently according to the way of oxidative stress treatment. Moreover, morphological changes in the cell membrane were more observable in the frequently stress treated cells than the temporarily stress treated cells.

• The Plant Pathology Journal
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• 제27권4호
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• pp.378-384
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• 2011

Tomato yellow leaf curl virus (TYLCV), a member of genus Begomovirus, was isolated in Korea in 2008. We sequenced and analyzed the DNA-A of 51 TYLCV isolates from Korea, and 13 of the TYLCV isolates were selected as type representatives of TYLCV from six Korean provinces. The 13 TYLCV isolates were classified into Korea Group 1 (KG1, nine isolates) and Korea Group 2 (KG2, four isolates) based on the results of phylogenetic analysis and genome size (2774 and 2781 nucleotides, respectively). A recombination detection program 3 (RDP3) revealed two recombinations between the TYLCV Korea isolates and other TYLCV isolates [Thailand (AF206674), Iran (AJ132711), and Israel (X76319)]. TYLCV Jeju isolate was characterized by two recombination events (E1 and E2) caused by the presence of E1 in ORF V1 and C3, which may seem to be the mutations of the high nucleotide transversion and transition rate. Collectively, our results suggest that the occurrence of nucleotide transversions and transitions in TYLCV DNA-A might have induced novel recombination events within the TYLCV Korea isolates.

• Journal of Korean Neurosurgical Society
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• 제58권3호
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• pp.205-210
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• 2015

Objective : This study was aimed at optimizing the treatment of non-small-cell lung cancer (NSCLC) patients who are candidates for stereotactic radiosurgery (SRS) for brain metastases and harbor activating epithelial growth factor receptor (EGFR) mutations. Methods : We retrospectively reviewed the medical records from 2005 to 2010 of NSCLC patients with brain metastases harboring an activating EGFR mutation. Patients who received a combination therapy of SRS and EGFR-tyrosine kinase inhibitor (TKI) for brain metastases and those who received SRS without EGFR-TKI were compared. The primary endpoint was progression-free survival (PFS) of the brain metastases. Results : Thirty-one patients were eligible for enrolment in this study (SRS with TKI, 18; SRS without TKI, 13). Twenty-two patients (71.0%) were women and the median overall age was 56.0 years. PFS of brain lesions was not significantly prolonged in SRS with TKI treatment group than in SRS without TKI group (17.0 months vs. 9.0 months, p=0.45). Local tumor control rate was 83.3% in the combination therapy group, and 61.5% in the SRS monotherapy group (p=0.23). There were no severe adverse events related with treatment in both groups. Conclusions : Therapeutic outcome of concurrent SRS and TKI treatment was not superior to SRS monotherapy, however, there was no additive adverse events related with combined treatment.

• 대한한방내과학회지
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• 제26권2호
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• pp.291-301
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• 2005

Objective : Anticancerous and host safety effects of the combination of Astragali Radix and chlorambucil are studied when it is applied to leukemia cell(P388D1 cell) related disease. Methods : After 5 groups of mice are treated by respective procedures (HG, CHL, HG+CHL, etc), the quantitative analyses (cell proliferation assay, mutagenesis test, survival rate, weight shift observation, tissue and blood analyses, etc) are conducted. Results : While sole injection of Astragali Radix extends the survival period and deter the liver and marrow function deterioration, combined injection (HG+CHL) shows more strong anticancerous effect than sole injection of Astragali Radix or Cholrambucil, and also does not cause any mutation on the normal cells and virulence on marrow and liver caused by leukemia. Conclusions : The combined application of Astragali Radix and chlorambucil has more effective anticancerous and host safety effects than independent use of them.