• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.76-81
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• 2006

Purpose : This study evaluated the clinical characteristics of brain tumors in children according to their location, the parental delay and the doctor's delay between the onset of symptoms and the diagnosis of a pediatric brain tumor. In addition, this study compared the relationship between the pre-diagnostic symptomatic interval and the tumor location. Methods : A retrospective study was undertaken of 45 children with primary brain tumors admitted to Inha Hospital from July, 1986 to June, 2004. A diagnosis of the tumor location was made using brain MRI. Results : The male to female ratio was 1 : 0.67. The median age at diagnosis was 6.0 years in supratentorial tumors, 7.0 years in infratentorial tumors. Twenty four cases(53.3 percent) were located in the supratentorial area, 21 cases(46.6 percent) were located in the infratentorial area. The distribution of supratentorial tumors were 14(58.3 percent) in the cerebral hemisphere and temporal lobe, seven (29.1 percent) in the suprasellar area, and three(12.5 percent) in the pineal gland and posterial lateral ventricle. The distributions of the infratentorial tumors were 12(57.1 percent) in the cerebellar vermis and fourth ventricle, four(19.1 percent) in the brain stem, and five(23.8 percent) in the cerebellar hemisphere. The most common initial symptom was seizure(37.5 percent) in the supratentorial tumor and headache(38.0 percent) in infratentorial tumors. The median pre-diagnostic symptomatic interval (PSI) was 21 days(range 0-240 days). The median PSI with a parental delay in supratentorial tumor was six days(range 1-240 days), and 30 days(range 1-40 days) in the infratentorial tumor. We immediately diagnosed most cases after visiting the hospital. There was no significant relationship between the tumor location and the pre-diagnostic symptomatic interval. Conclusion : The most common symptom of supratentorial tumors and infratentorial tumors was seizure and headache, respectively. Although, the median pre-diagnostic symptomatic interval was shorter than in previous studies, a detailed medical history and a correctly interpreted neurological examination should lead to an earlier diagnosis of pediatric brain tumors.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.333-343
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• 2012

In-stream large wood (LW) has a critical impact on the geomorphic characteristics relevant to ecosystem management and disaster prevention, yet relatively little is known about variations in its dynamics and subsequent export on the watershed-scale perspective in Korea. Here we review variations in the dynamics and subsequent export of LW as a function of stream size, which is appropriate for Korean mountain streams. In upstream channels with narrow bankfull widths and low stream discharges, a massive amount of LW, resulting from forest dynamics and hillslope processes, may persist for several decades on valley floor. These pieces, however, are eventually transported during infrequent debris flows from small tributaries, as well as peak hydrology in main-stem channels. During the transport, these pieces suffer fragmentation caused by frictions with boulders, and stream bank and bed. Although infrequent, these events can be dominant processes in the export of significant amounts of LW from upstream channel networks. In downstream channels with wide bankfull widths and high stream discharges, LW is dominantly recruited by forest dynamics and bank erosion only at locations where the channel is adjacent to mature riparian forests. With the LW pieces that are supplied from the upstream, these pieces are continuously transported downstream during rainfall events. This leads to further fragmentation of the LW pieces, which increases their transportability. With decreasing stream-bed slope, these floated LW pieces, however, can be stored and form logjams at various depositional sites, which were developed by interaction between channel forms and floodplains. These pieces may decay for decades and be subsequently transported as particulate or dissolved organic materials, resulting in the limitation of LW fluvial export from the systems. However, in Korea, such depositional sites were developed in the extremely limited streams with a large dimension and no flood history for decades, and thus it does not be expected that the reduction of LW export amount, which can be caused by the long-term storage. Our review presents a generalized view of LW processing and is relevant to ecosystem management and disaster prevention for Korean mountain streams.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.13-18
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• 2003

This study was carried out to investigate the expression patterns of foreign gene that controlled by tuber-specific patatin promoter in transgenic potatoes. Potato leaf disc cultured in vitro were transformed by the Agrobacterium strain LBA4404 containing pBl121 or pATGUS from potato cv. Desiree. In order to select the transgenic lines, gene-specific primers deduced from the NPTII were synthesized and used for polymerase chain reaction. The down part of the putative transgenic potatoes was transplanted weekly onto sucrose-enriched medium to accelerate the microtuber formation. RNA gel blot analysis was performed on the total RNAs obtained from tuber that had been harvested at a week interval. Also, histochemical assay was observed in the explants transformed with either pBI121 or pATGUS. Results showed that the transgenic plant containing pATGUS expressed GUS transcripts mainly at the tuber, not in stem, with the highest expression level in 5 weeks-grown microtubers. In contrast to pATGUS plants, the transformed plants with pBI121 showed an equal expression pattern throughout the whole developing stages. Consistent with RNA gel blot analysis, histochemical GUS staining and enzyme activity exhibited pATGUS transcripts were at the highest level in 5 weeks cultures. From these results, we suggest that the best stage to analyze the foreign gene introduced by patatin promoter into potato plants is at 5 weeks cultures after tuber formation.

• Korean Journal of Remote Sensing
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• v.23 no.2
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• pp.145-152
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• 2007

The polarimetric backscattering coefficients of a wet-land rice field which is an experimental plot belong to National Institute of Agricultural Science and Technology in Suwon are measured using ground-based polarimetric scatterometers at 1.8 and 5.3 GHz throughout a growth year from transplanting period to harvest period (May to October in 2006). The polarimetric scatterometers consist of a vector network analyzer with time-gating function and polarimetric antenna set, and are well calibrated to get VV-, HV-, VH-, HH-polarized backscattering coefficients from the measurements, based on single target calibration technique using a trihedral corner reflector. The polarimetric backscattering coefficients are measured at $30^{\circ},\;40^{\circ},\;50^{\circ}\;and\;60^{\circ}$ with 30 independent samples for each incidence angle at each frequency. In the measurement periods the ground truth data including fresh and dry biomass, plant height, stem density, leaf area, specific leaf area, and moisture contents are also collected for each measurement. The temporal variations of the measured backscattering coefficients as well as the measured plant height, LAI (leaf area index) and biomass are analyzed. Then, the measured polarimetric backscattering coefficients are compared with the rice growth parameters. The measured plant height increases monotonically while the measured LAI increases only till the ripening period and decreases after the ripening period. The measured backscattering coefficientsare fitted with polynomial expressions as functions of growth age, plant LAI and plant height for each polarization, frequency, and incidence angle. As the incidence angle is bigger, correlations of L band signature to the rice growth was higher than that of C band signatures. It is found that the HH-polarized backscattering coefficients are more sensitive than the VV-polarized backscattering coefficients to growth age and other input parameters. It is necessary to divide the data according to the growth period which shows the qualitative changes of growth such as panicale initiation, flowering or heading to derive functions to estimate rice growth.