• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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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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• v.6 no.3
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• pp.146-153
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• 2006

Purpose: Gastrointestinal stromal tumorsm (GISTs) are the most common mesenchymal tumors that arise anywhere in the tubular GI tract. The prognosis for GSTIs is important because f GISTs may metastasiwx in the liver or the abdominal cavity in an early stage. For the reason we examined the tumor size, the mitotic number, ki 67, p53, and c-kit mutation as independent prognostic factor for GISTs. Materials and Methods: A retrospective study was conducted in 76 patients who had been re-evaluated for confirmation of diagnosis between Jan 1998 and Dec. 2001. at Catholic University of medicine. Results: There were significant difference between the turner size, mitotic indices, ki 67, c-kit mutations and the 5-years survival rates. Tumor size (${\geq}5\;cm$) and mitotic index (${\geq}5/50\;HPF$) were statistically related to a significantly poor prognosis (P=0.017 and P=0.042, respectively). c-kit mutations in exon 11 were found in 7 cases c-kit mutation was observed more frequently in high risk patients, and there was a significant difference between c-kit mutation and survival (P=0.037). Elevated ki 67 was noted in 34 out of the 76 cases. High risk patients showed elevated ki67 index more frequently and there was significant relation with the survival rate (P=0.0417). Conclusion: We think that tumor size, mitotic index, Ki 67 and c-kit mutation are as independent prognostic factors for GISTs, but more research is needed.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.177-182
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• 2005

H. pylori strains were isolated from antral biopsies taken during upper endoscopy in 114 dyspeptic patients with no previous therapy against H. pylori. Rapid urease test, PCR amplification of SSA and cagA gene for H. pylori detection, and Western blot for CagA expression detection were performed. H. pylori infected patients were treated with omeprazole, clarithromycin (a macrolide), and amoxicillin. At 6 weeks after the discontinuation of therapy, the bacterial eradication rate was determined by endoscopy. The resistance rate to clarithromycin and amoxicillin was $20.2\%$ and $0.0\%$, respectively. The clarithromycin resistance was mainly caused by the A2142G mutation in the 23S rRNA gene of H. pylori. MICs of clarithromycin for the A2142G mutant isolates were significantly higher than MICs for the A2143G mutant isolates. H. pylori eradication was obtained in all patients with clarithromycin-susceptible isolates but not in patients with clarithromycin-resistant isolates (P = 0.0001). These results did not appear to be biased by any differences in CagA expression. The resistance of H. pylori to clarithromycin included in the therapeutic regimens is the most important reason for treatment failure. H. pylori antimicrobial susceptibility testing of the gastric biopsy culture should be performed before choosing the first triple therapy in infected patients and the increase in prevalence of clarithromycin resistance in Korea was problematic.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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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.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.200-207
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• 2018

At high salt concentration, glycine betaine is transported into Bacillus subtilis and growing rate of the cell is not suppressed. Also according to recent studies, cell growth is maintained normal growth rate at low temperature. Low temperature results in a stress response of Bacillus subtilis that is characterized by strong repression of major metabolic activities such as translation machinery and membrane transport. In this regards, genes showing cold sensitive phenotype are cold-induced DEAD box RNA helicases (ydbR, yqfR) and fatty acid desaturases (bkdR, des). Therefore to understand the effect of glycine betaine on cold growth of Bacillus subtilis, we investigated the effect of glycine betaine on growth rate of these deletion mutants showing cold sensitive phenotype. Glycine betaine strongly stimulated growth of wild type Bacillus subtilis JH642 and deletion mutants of ydbR and yqfR at $20^{\circ}C$ (190~686 min $T_d$ difference). On the other hands, glycine betaine does not show growth promoting effects on deletion mutants of bkdR, and des at cold conditions. Same cold protectant growth results were shown with the precursor choline instead of glycine betaine. We investigated the effects of detergents on the cell membrane in bkdR and des deficient strains associated with cell membrane. It was identified that bkdR deficient strain shows retarded growth with detergent such as Triton X-100 or N-lauryl sarcosine compared with wild type cell. Thus, it is possible that deletion mutation of bkdR modifies membrane structure and effects on transport of glycine betaine.

• The Korean Journal of Cytopathology
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• v.7 no.2
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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.

• Korean Journal of Environmental Biology
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• v.28 no.2
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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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• v.27 no.4
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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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• v.58 no.3
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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.

• The Journal of Internal Korean Medicine
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• v.26 no.2
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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.