• Development and Reproduction
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• v.12 no.1
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• pp.87-95
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• 2008

Neural stem/precursor derived from pluripotent human embryonic stem cells (hESCs) has considerable therapeutic potential due to their ability to generate various neural cells which can be used in cell-replacement therapies for neurodegenerative diseases. However, production of neural cells from hESCs remains technically very difficult. Understanding neural-tube like rosette characteristic neural precursor cells from hESCs may provide useful information to increase the efficiency of hESC neural differentiation. Generally, neural rosettes were derived from differentiating hEBs in attached culture system, however this is time-consuming and complicated. Here, we examined if neural rosettes could be formed in suspension culture system by bypassing attachment requirement. First, we tested whether the size of hESC clumps affected the formation of human embryonic bodies (hEBs) and neural differentiation. We confirmed that hEBs derived from $500{\times}500\;{\mu}m$ square sized hESC clumps were effectively differentiated into neural lineage than those of the other sizes. To induce the rosette formation, regular size hEBs were derived by incubation of hESC clumps($500{\times}500\;{\mu}m$) in EB medium for 1 wk in a suspended condition on low attachment culture dish and further incubated for additional $1{\sim}2$ wks in neuroectodermal sphere(NES)-culture medium. We observed the neural tube-like rosette structure from hEBs after $7{\sim}10$ days of differentiation. Their identity as a neural precursor cells was assessed by measuring their expressions of neural precursor markers(Vimentin, Nestin, MSI1, MSI2, Prominin-1, Pax6, Sox1, N-cadherin, Otx2, and Tuj1) by RT-PCR and immunofluorescence staining. We also confirmed that neural rosettes could be terminally differentiated into mature neural cell types by additional incubation for $2{\sim}6$ wks with NES medium without growth factors. Neuronal(Tuj1, MAP2, GABA) and glial($S100{\beta}$ and GFAP) markers were highly expressed after $2{\sim}3$ and 4 wks of incubation, respectively. Expression of oligodendrocyte markers O1 and CNPase was significantly increased after $5{\sim}6$ wks of incubation. Our results demonstrate that rosette forming neural precursor cells could be successfully derived from suspension culture system and that will not only help us understand the neural differentiation process of hESCs but also simplify the derivation process of neural precursors from hESCs.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.4
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• pp.87-97
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• 2015

There's a trend towards vitalization of nightscape planning businesses nationally and locally as well for city image making and activation of regional economy, but there is still no systematic nightscape planning going on for lack of relevant researches and objective evaluations. This study aims to suggest the guideline for nightscape planning by conducting an eye tracking experiment and survey for recognizing the characteristics of a nightscape. Furthermore, the authors intended to verify the eye-tracking method as a tool for landscape evaluation. The research site was restricted in the campus of Virginia Tech, VA, and those were selected by experts' survey among various types of nightscape images. The variables for analyzing the characteristics of nightscape images selected were 'preference', 'safety(fear)' and 'clearness'. 'Fixation duration', 'saccade duration', 'scan path length', and 'pupil size' were selected as the eye movement measurements. The results of this study are as follows: The first outcome found was that there were significant differences among the characteristics(preference, safety and clearness) of a nightscape by MANOVA, and these variables were correlated positively by Pearson's correlation. Secondly, there were differences on fixation duration, saccade duration and scan path depending on the nightscape setting statistically. Also, the eye tracking measurement in an open setting was recorded lower than enclosed settings. In the result of a heat map, we found the meaning of the fixated areas on both viewing without intention and viewing intentionally. It turned out that the fixated areas were consistent with the areas the subjects felt preferred and clarity in all of the nightscape images, which means people usually focus on what they prefer and see clearly in a certain nightscape. Based on this result and previous studies, the authors could make a conclusion that eye tracking method can apply to evaluate nightscape settings in terms of analyzing the whole characteristics and finding specific points for the detailed analysis as well. Therefore, these results can contribute by suggesting nightscape planning, implication of the landscape evaluation, and implication of the eye tracking study.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.589-600
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• 2020

Effective conservation and management of protected areas require monitoring the settlement of invasive alien species and reducing their dispersion capacity. We simulated the potential distribution of invasive alien plant species (IAPS) using three representative species distribution models (Bioclim, GLM, and MaxEnt) based on the IAPS distribution in the forest genetic resource reserve (2,274ha) in Uljin-gun, Korea. We then selected the realistic and suitable species distribution model that reflects the local region and ecological management characteristics based on the simulation results. The simulation predicted the tendency of the IAPS distributed along the linear landscape elements, such as roads, and including some forest harvested area. The statistical comparison of the prediction and accuracy of each model tested in this study showed that the GLM and MaxEnt models generally had high performance and accuracy compared to the Bioclim model. The Bioclim model calculated the largest potential distribution area, followed by GLM and MaxEnt in that order. The Phenomenological review of the simulation results showed that the sample size more significantly affected the GLM and Bioclim models, while the MaxEnt model was the most consistent regardless of the sample size. The optimal model overall for predicting the distribution of IAPS among the three models was the MaxEnt model. The model selection approach based on detailed flora distribution data presented in this study is expected to be useful for efficiently managing the conservation areas and identifying the realistic and precise species distribution model reflecting local characteristics.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.189-194
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• 2011

This study used magnetic resonance diffusion tensor imaging (DTI) to quantitatively analyze the neural fiber tractography according to the age of normal corpus callosum and to evaluate of usefulness. The research was intended for the applicants of 60 persons that was in a good state of health with not brain or other disease. The test parameters were TR: 6650 ms, TE: 66 ms, FA: $90^{\circ}$, NEX: 2, thickness: 2 mm, no gap, FOV: 220 mm, b-value: $800s/mm^2$, sense factor: 2, acquisition matrix size: $2{\times}2{\times}2mm^3$, and the test time was 3 minutes 46 seconds. The evaluation method was constructed the color-cored FA map include to the skull vertex from the skull base in scan range. We set up the five ROI of corpus callosum of genu, anterior-mid body, posterior-mid body, isthmus, and splenium, tracking, respectively, and to quantitatively measured the length of neural fiber. As a result, the length of neural fiber, for the corpus callosum of genu was 20's: $61.8{\pm}6.8$, 30's: $63.9{\pm}3.8$, 40's: $65.5{\pm}6.4$, 50's: $57.8{\pm}6.0$, 60's: $58.9{\pm}4.5$, more than 70's: $54.1{\pm}8.1mm$, for the anterior-mid body was 20's: $54.8{\pm}8.8$, 30's: $58.5{\pm}7.9$, 40's: $54.8{\pm}7.8$, 50's: $56.1{\pm}10.2$, 60's: $48.5{\pm}6.2$, more than 70's: $48.6{\pm}8.3mm$, for the posterior-mid body was 20's: $72.7{\pm}9.1$, 30's: $61.6{\pm}9.1$, 40's: $60.9{\pm}10.5$, 50's: $61.4{\pm}11.7$, 60's: $54.9{\pm}10.0$, more than 70's: $53.1{\pm}10.5mm$, for the isthmus was 20's: $71.5{\pm}17.4$, 30's: $74.1{\pm}14.9$, 40's: $73.6{\pm}14.2$, 50's: $66.3{\pm}12.9$, 60's: $56.5{\pm}11.2$, more than 70's: $56.8{\pm}11.3mm$, and for the splenium was 20's: $82.6{\pm}6.8$, 30's: $86.9{\pm}6.4$, 40's: $83.1{\pm}7.1$, 50's: $81.5{\pm}7.4$, 60's: $78.6{\pm}6.0$, more than 70's: $80.55{\pm}8.6mm$. The length of neural fiber for normal corpus callosum were statistically significant in the genu(P=0.001), posterior-mid body(P=0.009), and istumus(P=0.012) of corpus callosum. In order of age, the length of neural fiber increased from 30s to 40s, as one grows older tended to decrease. For this reason, the nerve cells of brain could be confirmed through the neural fiber tractography to progress actively in middle age.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.239-244
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• 2020

Effect of 6kg large unit with the carton box (20% open ratio) and MA box (10,000cc·m^-2·day^-1·atm^-1 oxygen transmission rates modified atmosphere package), and the 100g small unit with MA film on asparagus sensory quality were evaluated. The CO₂ concentration depended largely on the packing unit and maintained at around 3% in small MA packages, whereas in the MA box increased to 12%. Ethylene concentration rapidly increased until after 3 days of storage in MA packages and then decreased to maintain 5μL·L^-1. Unrelated to the unit size, the lower weight loss was obtained in MA packages. A significant difference in visual quality was shown since the 15th day, the best and worst were the MA box and small MA package on the finish day. Off-odor was the highest in small MA packages and the lowest in the carton box (< 3.0). Although there was no significant difference in firmness among all treatments, the packages showed the highest firmness in tips and stems, respectively. The sugar content and hue angle decreased during storage, but there was no statistical difference in all treatments. EL was lowest and highest in small MA package and carton box, respectively. On the 10th day, the total aerobic bacteria was lowest in small MA packages, but no significant difference on the 20th day. E. coli was not found in all treatments on the 10th day, while it was the lowest in the MA box on the 20th day. The mold and yeast were not observed during the whole storage. Based on the above results, the carton box packaged with 10,000cc OTR film was more effective in maintaining the quality of green asparagus with the suitable CO₂ concentration for asparagus cold storage.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.1-14
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• 2017

In Korea, the soil series derived from sedimentary rocks are classified into seven soil series of coarse loamy soil such as Dain, Danbug, Dongam, Imdong, Jeomgog, Maryeong, and Yonggog; seventeen soil series of fine loamy soil such as Angye, Anmi, Banho, Bigog, Deoggog, Dogye, Dojeon, Gamgog, Gugog, Jincheon, Maji, Mungyeong, Oggye, Samam, Yanggog, Yeongwol, and Yulgog; six soil series of fine silty soil such as Goryeong, Bonggog, Juggog, Gyeongsan, Yuga, and Yugog; and four soil series of clayey soil such as Mitan, Pyeongan, Pyeongjeon, and Uji. All thirty-four soil series have different drainage rates and topography. However, the soil texture depends on the parent rock. The buffer functions in GIS (Geographic Information System) techniques were used to calculate adjacent soil series from a soil series. The length of the adjacent soil series was adjusted because a side of the buffer area was one meter long. The cluster analysis was conducted using the CCC (Cubic Clustering Criterion) method, in which the number of clusters is calculated based on the individual soil series ratio. Soil survey has been carried out since 1964 as "The reconnaissance soil survey", and 1:5,000 detailed soil survey was completed in 1999 with a five-years plan in Korea. Today, all the soil survey information has been computerized. GIS techniques were used to establish a digital soil map; however, there have not been any studies to interpret pedogenesis using the GIS technique. In this study, the area of the adjacent soil series were obtained using the GIS technique. The area of the adjacent soil series can be calculated based on the information area. The similarities of soil originated from sedimentary rocks were estimated using the length. As a result, the distribution of grain size was different based on the types of sedimentary rocks and the location. The clusters were distinguished into limestone, sandstone, and shale. In addition, the soil derived from shale was divided into red shale and gray shale. This means that quantitative interpretation of the catena and this established method can be used to interpret the relationship between soil series.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.645-651
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• 2007

In general, contours in digital vector maps, which represent terrain characteristics and shape, are created by 3D digitizing the same height points using aerial photographs on the analytical or digital plotters with stereoscopic viewing. Hence, it requires lots of task, and subjective decision and experience of the operators. DTMs are generated indirectly by using contours since the national digital maps do not include digital terrain model (DTM) data. In this study, model key points which depict the important information about terrain characteristics were extracted from the contours. Further, determination of the efficient and flexible grid sizes were proposed to generate optimal DTM in terms of both quantitative and qualitative aspects. For this purpose, a progressive sampling technique was implemented, i.e., the smaller grid sizes are assigned for the mountainous areas where have large relief while the larger grid sizes are assigned for the relatively flat areas. In consequence, DTMs with multi-grid for difference areas could be generated instead of DTMs with a fixed grid size. The multi-grid DTMs reduce computations for data processing and provide fast display.

• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.632-639
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• 2008

This paper deals with feeding site distribution aspect and seasonal distribution change of the wintering geese in Cheonsu bay and reclaimed area from October 2006 to March 2007. Geese were distributed mostly in agricultural land(rice field) during day time. According to the distribution map by maximum counts, observed geese of agricultural land were frequently distributed in large agricultural land. Especially, Geese were more used agricultural land near the reservoir where used as roosting site than the other sites. Diurnal feeding site of the geese were agricultural land near the reservoir with huge flock during early wintering season(October), but geese were used the agricultural land far from reservoir after mid wintering season(after January). The feeding flock size of Geese were decreased and feeding site was more far from the reservoir than in mid wintering season during late wintering season(March). Habitat use rate of the quadrat area where below 1km from the reservoir was most high in early wintering season. Contrary, habitat use rate where 2km far from the reservoir was shown lowest habitat use rate in early wintering season, but it was increased during mid wintering season(January) and decreased after mid wintering season. Habitat use rate of the agricultural land where 2km below and 1 km far from reservoir was shown middle rate, but it was increased until November and decreased after November. This result shown that feeding site preference of the wintering geese was affected by distance from roosting site(reservoir), and feeding site was changed as a food sources decreasing by stay time of geese flock.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.3 s.309
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• pp.30-38
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• 2006

In this paper, we improved to drops recognition rate according to distance using distance and depth information with 3D from stereo face images. A monocular face image has problem to drops recognition rate by uncertainty information such as distance of an object, size, moving, rotation, and depth. Also, if image information was not acquired such as rotation, illumination, and pose change for recognition, it has a very many fault. So, we wish to solve such problem. Proposed method consists of an eyes detection algorithm, analysis a pose of face, md principal component analysis (PCA). We also convert the YCbCr space from the RGB for detect with fast face in a limited region. We create multi-layered relative intensity map in face candidate region and decide whether it is face from facial geometry. It can acquire the depth information of distance, eyes, and mouth in stereo face images. Proposed method detects face according to scale, moving, and rotation by using distance and depth. We train by using PCA the detected left face and estimated direction difference. Simulation results with face recognition rate of 95.83% (100cm) in the front and 98.3% with the pose change were obtained successfully. Therefore, proposed method can be used to obtain high recognition rate with an appropriate scaling and pose change according to the distance.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.451-457
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• 2012

One decade early onset of the breast cancer in Iranian females was reported but the basis of the observed difference has remained unclear and difference in gene silencing by epigenetic processes is suggested. Hence, this study was sought to map the methylation status of estrogen receptor (ER) gene CpG islands and its impact on clinicopathological factors of triple negative and non-triple negative ductal cell carcinoma of the breast in Iranian females. Surgically resected formalin-fixed paraffin-embedded breast tissues from sixty Iranian women with confirmed invasive ductal carcinoma were assessed by methylation-specific PCR using primer sets encompassing some of the 29 CpGs across the ER gene CpG island. The estrogen and progesterone receptors, Her-$2^+$ overexpression, and nuclear accumulation of P53 were examined using immunohistochemistry (IHC). Methylated ER3, ER4, and ER5 were found in 41.7, 11.3, and 43.3% of the samples, respectively. Significantly higher methylation of ER4 was found in the tumors with nuclear accumulation of P53, and significantly higher methylation of ER5 was found in patients with lymph node involvement and tumor with bigger size or higher grades. Furthermore, significantly higher rate of ER5 methylation was found in patients with Her-$2^+$ tumors and in postmenopausal patients with $ER^-$, $PgR^-$, or $ER^-/PgR^-$ tumors. However, no significant difference in ERs methylation status was found between triple negative and non-triple negative tumors in pre- and postmenopausal patients. Findings revealed that aberrant hypermethylation of the ER-alpha gene frequently occurs in Iranian women with invasive ductal cell carcinoma of the breast. However, methylation of different CpG islands produced a diverse impact on the prognosis of breast cancer, and ER5 was found to be the most frequently methylated region in the Iranian women, and could serve as a marker of poor prognosis.