• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.147-153
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• 2007

Kaolinite [$Al_2Si_2O_5(OH)_4$] was successfully synthesized by a hydrothermal process from amorphous $Al(OH)_3$ and $SiO_2$ at $230^{\circ}C$ under the pressure of $30 kg/cm^2$. The experiments were performed varying temperatures ($180{\sim}280^{\circ}C$), pressure ($10{\sim}60kg/cm^2$), chemistry ($Al_2O_3/SiO_2 = 0.5{\sim}0.38$) and pH ($0.3{\sim}9.5$) of the solution. The autoclaving was carried out in a closed stainless steel vessel. Kaolinite appears from the starting composition of $Al_2O_3/SiO_2= 0.5$ with boehmite and was stable as a single phase with the composition of $Al_2O_3/SiO_2=0.45$. Boehmite was a stable phase below $200^{\circ}C$ for the 240 h period of autoclaving, but kaolinite appeared even in 20 h at $230^{\circ}C$. The single kaolinite phase of a good crystallinity was observed at pH ranging 2 to 6. That indicates that pH is one of the most critical parameters for the successful formation of kaolinite. The optimal molar ratio of $Al_2O_3$ to $SiO_2$ was determined to be 0.45. The XRD pattern of the synthesized kaolinite coincided with that of natural one and its morphology was the cluster type of the kaolinite crystals (diameter = ${\sim}3{\mu}m$), irrespective of starting material, composition and temperature.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.447-458
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• 2001

The purpose of this study was to evaluate 1) in vivo, the expression of chondroitin 4-sulfate (CH-4S), a structural element of glycosaminoglycans(GAGs), in periodontal tissue during the experimental movement of rat incisors, by labelled streptavidine biotin immunohistochemical staining for CH-4S, 2) In vitro, the expression of CH-4S in cultured human periodontal ligament(PDL) cells supplemented with 10ng/ml of $TGF-{\beta}_1$, 20ng/ml of PDGF-BB, 1ng/ml $TNF-\alpha$, or $1{\mu}g/ml$ LPS by western blot analysis. The results of this study were as follows ; 1. The expression of CH-4S was stronger in pulp, PDL, osteoblasts, osteoclasts and osteocytes in experimental group than in control group, but was rare in dentin, and cementum of experimental groups, regardless of the duration of force application, which was not different from that of control group. 2. In experimental group, the expression of CH-4S in pulp began to increase at 1 day after force application and got to the highest degree at 7 days. After 14 days, the expression in CH-4S immunoreactivity was decreased, and became similar to that of control group at 28 days. 3. The expression of CH-4S in PDL was noted in adjacent to alveolar bone. PDL showed higher intensity of immunolabelling after 1 day of orthodontic tooth movement. And the expression was more stronger in the tension side than that of pressure side of PDL at 1 day, but more stronger in the pressure side than that of tension side of PDL at 4 days. After 7 days, a decrease in CH-4S expression was observed. 4. The expression of CH-4S in alveolar bone got to the highest degree at 4 days, and At 7 days, a decrease in CH-4S expression was observed. 5. PDGF-BB notably raised the expression of CH-4S in the PDL cells at 3 days of cultivation 6. The expression of CH-4S of PDL cells was decreased with the application of $TNF-\alpha$ at 1 day. 7. Admixture of $TGF-{\beta}_1$ and PDGF-BB got more expression of CH-4S in PDL as compared to only $TGF-{\beta}1$ or PDGF-BB. A similar decrease of the expression of CH-4S was observed in the case of application of LPS or $TNF-\alpha$.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.2
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• pp.1-15
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• 2002

Atmospheric aerosols interact with sunlight and affect the global radiation balance that can cause climate change through direct and indirect radiative forcing. Because of the spatial and temporal uncertainty of aerosols in atmosphere, aerosol characteristics are not considered through GCMs (General Circulation Model). Therefor it is important physical and optical characteristics should be evaluated to assess climate change and radiative effect by atmospheric aerosols. In this study GMS-5 satellite data and surface measurement data were analyzed using a radiative transfer model for the Yellow Sand event of April 7~8, 2000 in order to investigate the atmospheric radiative effects of Yellow Sand aerosols, MODTRAN3 simulation results enable to inform the relation between satellite channel albedo and aerosol optical thickness(AOT). From this relation AOT was retreived from GMS-5 visible channel. The variance observations of satellite images enable remote sensing of the Yellow Sand particles. Back trajectory analysis was performed to track the air mass from the Gobi desert passing through Korean peninsular with high AOT value measured by ground based measurement. The comparison GMS-5 AOT to ground measured RSR aerosol optical depth(AOD) show that for Yellow Sand aerosols, the albedo measured over ocean surfaces can be used to obtain the aerosol optical thickness using appropriate aerosol model within an error of about 10%. In addition, LIDAR network measurements and backward trajectory model showed characteristics and appearance of Yellow Sand during Yellow Sand events. These data will be good supporting for monitoring of Yellow Sand aerosols.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.46-53
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• 1996

Background: Endotoxin or lipopolysaccharide(LPS) can prime phagocytic cells such as polymorphonuclear leukocytes, monocytes or animal peritoneal macrophages to generate increased amounts of secretory products such as oxygen free radicals and tumor necrosis factor, which play an important role in developing adult respiratory distress syndrome in gram negative sepsis. Human alveolar macrophages(HAM) are continuously exposed to various stimuli inhaled into the alveoli, and the response to LPS might be different in HAM. Therefore, we investigated the effect of LPS pre-exposure on HAM adhered to plastic surface and A549 cell(type II human alveolar epithelial cell line) monolayer. Methods: HAM were isolated from bronchoalveolar lavage fluid from normal lung of the patients with localized lung cancer and esophageal cancer. LPS was exposed to HAM for 2hrs before or after adherence to plastic surface of 24-well Linbro plate and A549 cell monolayer. And then HAM was stimulated with PMA(phorbol myristate acetate) or fMLP(N-formyl-methionylleucyl-phenylalanine). The amount of hydrogen peroxide($H_2O_2$) production in the supernatant was measured on the principle of peroxidase-dependent oxidation of phenol red by hydrogen peroxide. Results: LPS pre-exposure could not enhance $H_2O_2$ production in neither HAM adhered to plastic surface nor one to A549 cell monolayer. But LPS even in the absence of PMA or fMLP stimulation directly increased $H_2O_2$ release in HAM if added after the adherence to A549 cell monolayer. Conclusion: Endotoxin does not prime HAM, but may directly activate HAM adhered to alveolar epithelial cells. Further investagation will be necessary.

• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.656-663
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• 2005

Background : The B-type natriuretic peptide (BNP) is a cardiac neurohormone that is specifically secreted from the ventricles in response to volume expansion and a pressure overload. Differentiating congestive heart failure from the pulmonary causes of dyspnea is very important for patients presenting with acute dyspnea. Methods : A retrospective study was carried out on 261 patients who were admitted to the emergency department of Hanyang University Hospital due to acute dyspnea from March to July 2004. The serum BNP levels of the patients were measured using the ELISA method. Results : The BNP levels were 382, 111-1140 pg/ml (median, interquartile range) in the heart failure group (n=119) and 29, 7-81 pg/ml in the non-heart failure group (n=142). The BNP levels according to the subgroups of heart failure were 820, 354-1620 pg/ml, 1650, 239-1990 pg/ml, and 378, 106-1120 pg/ml for the chronic obstructive pulmonary disease (COPD) with combined left heart failure (n=5), cor pulmonale (n=3), and left heart failure groups (n=111), respectively. The BNP levels according to the subgroups of non-heart failure were 39, 21-101 pg/ml, 59, 10-129 pg/ml, and 15, 6-47 pg/ml for the COPD (n=20), other pulmonary diseases (n=56), and other causes groups (n=66), respectively. The BNP levels were significantly different according to the underlying etiology (p<0.001), and were significantly higher in the COPD patients with left heart failure than in those without (p=0.002). When the patients with no cardiovascular risk factor such as diabetes mellitus, hypertension, smoking or renal failure were analyzed, the BNP levels were also significantly higher in the patients with heart failure than in those without(p<0.001). When 133 pg/ml was designated as the BNP cut-off level the sensitivity for predicting heart failure was 73 percent and the specificity was 87 percent. Conclusion : BNP measurements are useful for determining the presence of heart failure in the patients presenting with acute dyspnea. The possibility of heart failure must be seriously considered in patients with high BNP levels even when they have a pre-existing pulmonary disease such as COPD or no risk factors for heart failure.

• Journal of Gastric Cancer
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• v.9 no.3
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• pp.104-109
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• 2009

Purpose: The aim of this study is to evaluate the accuracy of surgically diagnosing early gastric cancer (EGC) and lymph node metastasis, and to determine its role for performing limited surgery for EGC. Materials and Methods: We reviewed 369 patients who underwent gastrectomy for primary gastric carcinoma. The surgical diagnosis was evaluated by determining its sensitivity, specificity and accuracy, and this was compared with the preoperative examinations. Results: The sensitivity, specificity, and accuracy of the intraoperative diagnosis for EGC were 74.5%, 95.7% and 83.7%, respectively. The predictive value for EGC according to the intraoperative diagnosis was 95.7%. The surgical diagnosis of EGC showed higher specificity and a higher predictive value than preoperative examinations, which significantly reduced the risk of underestimating advanced gastric cancer (AGC) to EGC. The sensitivity, specificity, and accuracy for lymph node metastasis according to the surgical diagnosis were 73.2%, 78.1% and 76.4%, respectively. For 70 patients with a discrepancy in the diagnosis of EGC between the pre- and intra-operative diagnosis, the surgical diagnosis was correct in 63 (90%) patients, but the preoperative examinations were correct in only 7 (10%) patients. Conclusion: The surgical diagnosis showed better accuracy than the preoperative examinations for detecting EGC and lymph node metastasis. Our results suggest that the decision for conducting limited surgery based on the surgical diagnosis might reduce the risk of under-treatment of AGC to EGC better than the preoperative examinations.

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.70-78
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• 2008

Purpose: VEGF-C and VEGF-D are angiogenetic factors, and abnormal expression of E-cadherin hasa role in the progression of gastric carcinoma. The aim of this study was to evaluate the relationship between the expression of E-cadherin, VEGF-C and VEGF-D with the presence of lymph node metastases (LNM) using cytokeratin 18 in early gastric cancer (EGC). Materials and Methods: Immunohistochemical staining for E-cadherin, VEGF-C and VEGF-D was performed in 49 EGC patients from March 1997 to December 2002. To evaluate the real extent of LNM, 1,562 lymph nodes from 49 patients were re-examined with the use of cytokeratin 18. Results: Eleven (0.7%) LNM were newly found in 12.2% (n=6) of patients. The real LNM rate was 3.6% in mucosal invasive (m) cancer and 38.1% in submucosal invasive (sm). Stage migration was seen in three patients (6.1%). Abnormal expression of E-cadherin was detected in 36.7% of the patients and expression of VEGF-C and VEGF-D was detected in 16.3% and 36.7% of the patients, respectively. Abnormal expression of E-cadherin was significantly correlated with tumor differentiation (P=0.0103) and Lauren classification (P<0.0001). There was no positive relationship of VEGF-C and VEGF-D expression with the clinicopathological findings for EGC including LNM. However, the frequency of lymph node metastases was significantly higher in patients that demonstrated abnormal expression of E-cadherin with positive immunoreactivity of VEGF-C or VEGF-D (P=0.031). Conclusion: In present study, we could not demonstrate a relationship between the presence of LNM and expression of VEGF-C and VEGF-D in EGC. However, VEGF-C or VEGF-D expression, in addition to the abnormal expression of E-cadherin, was correlated with the real extent of LNM in EGC.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1034-1042
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• 2012

This study was performed by using an LFR (laminar flow reactor), which can be used to carry out different types of research on coal. In this study, an LFR was used to analyze coal flames, tar and soot yields, and structures of chars for two coals depending on their volatile content. The results show that the volatile content and oxygen concentration have a significant effect on the length and width of the soot cloud and that the length and width of the cloud under combustion conditions are less than those under a pyrolysis atmosphere. At sampling heights until 50 mm, the tar and soot yields of Berau (sub-bituminous) coal, which contains a large amount of volatile matter, are less than those of Glencore A.P. (bituminous) coal because tar is oxidized by the intrinsic oxygen component of coal and by radicals such as OH-. On the other hand, at sampling heights above 50 mm, the tar and soot yields of Berau coal are higher than those of Glencore A.P. coal by reacted residual volatile matter, tar and light gas in char and flame. With above results, it is confirmed that the volatile matter content and the intrinsic oxygen component in a coal are significant parameters for length and width of the soot cloud and yields of the soot. In addition, the B.E.T. results and the images of samples (SEM) obtained from the particle separation system of the sampling probe support the above results pertaining to the yields; the results also confirm the pore development on the char surface caused by devolatilization.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.6
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• pp.98-109
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• 2011

Habitat restoration initiative is an important factor for the on-site preservation of butterflies. A new habitat necessitates the investigation of the ecology of the butterfly, the landscape of the habitat, the work process, and a cost analysis. In this study, these factors were analyzed through1) re-consideration of the secured results from three years of field work, and 2) a habitat area estimation conducted according to the presence or absence of larvae and adults via a Parnassius bremeri Bremer survey. The investigation of the natural habitat, done for both larvae and adult butterflies found in South Korea, suggested that multiple patches with a minimum size exceeding $300m^2$ and with an average size of about $1,600m^2$were required for survival of this butterfly. Therefore, more than five patches should be considered for butterfly habitat and patches should have similarity to the present habitat environment with transplantation plans for diet plants and honeydew plants. In addition, to activate the migration of the butterfly, cutting down trees that are obstacles to migration, minimizing the distance between patches and the addition of a stepping patch are also required. A patch connectivity analysis showed that patches should be located within 300m of neighboring patches, as the migration of the butterfly will fail if it is more than 600m. Additionally, more than $10,000m^2$ for a single patch or a patch network composed more than five patches over $1,600m^2$ in size were recommended, with a total patch size of $8,000m^2$. Additionally, neighboring multiple patch networks are more desirable than a single habitat in the event a cyclic habitat pattern arises. In this study, we suggest a habitat restoration and optimal prerequisites for a butterfly habitat. It is expected that this research will lead to the creation of a good model for the restoration of butterfly species.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.469-477
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• 2020

Salinity is not only an important variable that determines the density of the ocean but also one of the main parameters representing the global water cycle. Ocean salinity observations have been mainly conducted using ships, Argo floats, and buoys. Since the first satellite salinity was launched in 2009, it is also possible to observe sea surface salinity in the global ocean using satellite salinity data. However, the satellite salinity data contain various errors, it is necessary to validate its accuracy before applying it as research data. In this study, the salinity accuracy between the Soil Moisture Active Passive (SMAP) satellite salinity data and the in-situ salinity data provided by the Ieodo ocean research station was evaluated, and the error characteristics were analyzed from April 2015 to August 2020. As a result, a total of 314 match-up points were produced, and the root mean square error (RMSE) and mean bias of salinity were 1.79 and 0.91 psu, respectively. Overall, the satellite salinity was overestimated compare to the in-situ salinity. Satellite salinity is dependent on various marine environmental factors such as season, sea surface temperature (SST), and wind speed. In summer, the difference between the satellite salinity and the in-situ salinity was less than 0.18 psu. This means that the accuracy of satellite salinity increases at high SST rather than at low SST. This accuracy was affected by the sensitivity of the sensor. Likewise, the error was reduced at wind speeds greater than 5 m s^-1. This study suggests that satellite-derived salinity data should be used in coastal areas for limited use by checking if they are suitable for specific research purposes.