• Korean Journal of Weed Science
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• v.12 no.2
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• pp.102-109
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• 1992

There was significant reduction in the mitotic indices of oat roots treated with alachlor. Uniform decrease in prophase, metaphase, anaphase, and telophase as treatment time increasing was observed. Alachlor did not disrupt mitosis, but rather inhibited the onset of mitosis. Labeled dividing cells were significantly inhibited, but the number of labeled interphase cells of all treatment were increased, as compared with control in 8 hr and 12hr period. Labeled dividing cells which entered mitosis thru $G_2$ were inhibited approximately 68% at 8hr after treatment with $1{\times}10^{-5}$ M of alachlor. Alachlor apparently inhibited from the $G_2$stage into mitosis of dividing cells. After 24 hr treatment, 12.1% abd 46.6% inhibition of coleoptile growth occurred at $1{\times}10^{-5}$ M and $1{\times}10^{-4}$ M, respectively. Cell elongation was inhibited by alachlor but was less sensitive than cell division. The longitudinal section cells of oat roots treated with $1{\times}10^{-4}$ M alachlor for 12 hr were observed to be enlarged central cylinder and also showed degradation of apical meristem zone, as compared with the untreated roots.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.300-304
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• 1987

Effects of benzyladenine (BA) on viability, cell wall regeneration and division of soybean (Glycine max, Var. Acme) protoplasts isolated from suspension cells of cotyledonary callus were investigated. The uptake of BA by the protoplasts was also studied. BA increased protoplast viability, and promoted cell wall regeneration and cell division. The level of BA in protoplasts was increased to a maximum at about 20 hour incubation and 2/3 of the total amount of BA accumulated in protoplast was absorbed within 6 hours.

• Journal of ILASS-Korea
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• v.3 no.3
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• pp.1-13
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• 1998

In this study, an experimental study was performed to investigate the breakup mechanism of vaporizing droplet. A well-controlled experimental apparatus was used to study breakup mechanisms of a monodisperse stream of drops injected into a transverse high temperature and velocity air stream. The experiments gave information$ about the microscopic structure of the liquid drop breakup process, drop breakup regimes, and drop trajectories in high temperature flow region. The breakup time, drop acceleration and wavelength of surface instability wave were measured from a high-magnification and double spark photography. The two instability theories, i.e., Kelvin-Helmholtz instability and Rayleigh-Taylor instability, were estimated by comparing the calculated data with the measurements. The results showed that the breakup time in high temperature flow condition is shortened because the surface tension is decreased by the increase of gas temperature.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.55-62
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• 2003

Patients with schizophrenia have thinking disorders such as delusion or hallucination, because they have a deficit in the ability which to systematize and integrate information. therefore, they cannot integrate or systematize visual, auditory and tactile stimuli. In this study, we suggest a virtual reality system for the assessment of cognitive ability of schizophrenia patients, based on the brain multimodal integration model. The virtual reality system provides multimodal stimuli, such as visual and auditory stimuli, to the patient, and can evaluate the patient's multimodal integration and working memory integration abilities by making the patient interpret and react to multimodal stimuli, which must be remembered for a given period of time. the clinical study showed that the virtual reality program developed is comparable to those of the WCST and the SPM.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.87-95
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• 2002

The aim of this article is to perform the numerical simulation far drop drag and breakup processes in air-assisted sprays using the Taylor analogy breakup (TAB) model with a modified drop drag model, in which a random method is newly used to consider the variation of the drop's frontal area. The predicted results for drop trajectory and Salter mean diameter (SMD) were compared with experimental data and the simulation results using the earlier published models such as TAH model, surface wave instability (Wave) model, and Wave model with original drop drag model. In addition, the effects of the breakup model constant, Ck, on prediction of spray behaviors were discussed. The results shows that the TAB model with the modified drop drag model is in better agreement with experimental data than the other models, indicating the present model is acceptable for predicting the drop breakup process in air-assisted sprays. At higher Weber numbers, the smaller Ck shows the best fitting to experimental data. It should be noted that more elaborated studies is required in order to determine the breakup model constant in the suggested model in the study.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.245-249
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• 1989

The effects of varying concentrations and durations of butachlor [N-(bytoxymety 1,)-2-chlor -2, 6-diethy lacetanilide treatment on oat(Avena sativa L.) root cell division and protein synthesis were studied. The highest concentration ($1{\times}10^{-3}M$) of butachlor caused the significant inhibition of cell division after 18hrs treatment. After 18hrs treatment, 59% and 82% inhibition of cell division occurred at $1{\times}10^{-4}M$ and $1{\times}10^{-3}M$, respectively, while 9% inhibition of cell division did at $1{\times}10^{-6}M$ concentration at the same exposure period. To investigate protein synthesis, the oats were treated for 18 and 24hrs with concentrations ranging from $1{\times}10^{-6}M$ to $1{\times}10^{-3}M$ butachlor. After 18hrs, butachlor treatment of oat with $1{\times}10^{-4}M$ inhibitited 23% protein synthesis, and butachlor treatment with $1{\times}10^{-4}M$ caused 34% inhibition after 24hrs. With SDS-PAGE of proteins extracted from oat root tips, butachlor usually inhibited the 16, 18, 30, 43 and 43.5 kD polypeptide, and proteins of root tips are made up of subunits below 100 kD polypeptide.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.57-64
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• 1999

Purpose : Paclitaxel is a chemotherapeutic agent with a potent microtubule stabilizing activity that arrests mitosis at G2-M phase of cell cycle which is the most radiosensitive period. Therefore paclitaxel is considered as a cell cycle-specific radiosensitizer. This study investigates the effect of paclitaxel on the radiation response of the normal large bowel mucosa of the rat. Materials and Methods: The rats were divided into the three groups i.e., single intraperitoneal infusion of paclitaxel (10 mg/kg), a single fraction of irradiation (8 Gy, x-ray) to the whole abdomen, and a combination of irradiation (8 Gy, x-ray) given 24 hours after paclitaxel infusion. The histological changes as well as kinetics of mitotic arrest and apoptosis were evaluated on the large bowel mucosa at 6 hours, 1 day, 3 days and 5 days after treatment with paclitaxel alone, radiation alone and combination of paclitaxel and radiation. Results : The incidence of the mitotic arrest was not increased by paclitaxel infusion. The apoptosis appeared in 24 hours after paclitaxel infusion, and the histopathologic changes such as vesiculation, atypia and reduction of the goblet cell of the mucosa of the large bowel were demonstrated during the period from 6 hours to 3 days after, and returned to normal in 5 days after paclitaxel infusion. In irradiated group, the apoptosis was increased in 6 and 24 hours after irradiation, and the histopathologic changes of the mucosa were appeared in 24 hours and markedly increased in 3 days and returned to normal in 5 days. In combined group of irradiation and paclitaxel infusion, the apoptosis was appeared in 3 days and the histopathologic changes appeared during the period from 6 hours to 3 days after infusion. On the basis of the incidence of apoptosis and the degree of the histopathologic changes of the large bowel mucosa, there seemed to be additive effect by paclitaxel on radiation rather than sensitizing effect. Conclusions: The histopathological changes of large bowel mucosa in combined group compared to radiation alone group suggested an additive effect of paclitaxel on radiation response in the large bowel of rat.

• Nuclear Engineering and Technology
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• v.17 no.1
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• pp.1-7
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• 1985

Non-destructive gamma-ray spectrometry was carried out on the spent PWR fuel assemblies at the spent fuel pool of reactor-site. Attention was focused on the determination of burnup distribution and cooling time. For the measurement of burnup distribution, the concentration ratio of $^{134}$ Cs$^{137}$ Cs was used and the results showed these ratios varied with the positions of assemblies in the core during their irradiation. For the measurement of cooling time, $^{144}$ Ce$^{137}$ Cs was used and the results were agreed considerably well with the operator declared cooling time.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.9-13
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• 1985

Protoplasts were isolated from cotyledons of germinating Pinus densiflora S. et Z. seeds. The seeds were germinated for nine days, and excised embryonic cotyledons about 3-4mm long were incubated with Cellulase Onozuka R-10 and Macerozyme. After 8 hours of incubation, large number of viable protoplasts were isolated. Isolated protoplasts were cultured in a medium containing basal salts of $B_5$ medium, vitamines, amino acids, organic acid, sugars, and growth hormones. The first evidence of protoplast budding was observed after twelve hours in culture, and it suggested that high potential of the embryonic cotyledons for rapid cell division affected the early budding, rather than effect of culture medium was shown in twelve hours. The three- to four-cell stage was reached after three to four days of culture. Most cell divisions were achieved by additional buddings rather than equal binary cell division. No further cell division was observed beyond the four-cell stage. Protoplasts isolated from fully expanded cotyledons (germinated for 17 to 24 days) seldom initiated or failed to initiate cell division.

• Journal of fish pathology
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• v.10 no.2
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• pp.177-186
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• 1997

To establish effectively for isolation and cultivation and cultivation of scuticociliata, we tried to culture scuticociliata using culture medium(P2Y1-DW medium). The number of scuticociliata reached $1.50{\times}10^3$ cells/ml at the temperature of $25^{\circ}C$ in 3 days, but $1.03{\times}10^2$ cells/ml at $15^{\circ}C$. In P1Y1-S medium growth reached $2.6{\times}10^4$cells/ml in 3 days, but the number in DW medium was the lowest with $2.0{\times}10^2$cells/ml. In all these media, the number decreased after 5 days. As the method of the parasite`s division, after attaching the anterior part of the body, its shape gradualy changed to a western pear-like appearance. The parasite completely divided into two cells, then freely swam and became an adult cell, size of $40{\mu}m$ in size within about 3 hours from attaching.