• KSBB Journal
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• v.23 no.5
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• pp.452-459
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• 2008

To obtain maximal efficacy with minimal systemic side-effects, many studies have been carried out to achieve the controlled release of 5-fluorouracil (5-FU). In this study, biodegradable poly(L-lactide) (L-PLA) microparticles containing 5-FU were prepared by a process, called aerosol solvent extraction system (ASES), utilizing supercritical carbon dioxide. The effects of various organic solvents, drug/polymer feeding ratio, polymer molecular weight, and blending with the same polymers with different molecular weights on the formation of 5-FU loaded microparticles were investigated under a predetermined operating condition from our previous study. The drug recovery, entrapment efficiency, and in vitro drug release kinetics were determined by HPLC assays. The drug recovery obtained from the ASES process was found to be very high, whereas the drug entrapment efficiency was considerably low in all the experiments due to the poor affinity between L-PLA and 5-FU. These results indicated that the precipitation rate of L-PLA might be quite different from that of 5-FU so that there was little chance to form 5-FU loaded L-PLA microparticles.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.132-138
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• 2016

The objectives of this study were to infer the parameters of forest stand growth functions of STEMS for Cryptomeria japonica stands of Jeju Hannam Experimental Forest, Korea Forest Research Institute, and to investigate the effects of thinning regimes on the patterns of stand growth and carbon absorption. The forest stand growth functions for the potential diameter growth, modifier, crown ratio and mortality are the major ones composing the independent-tree/distance-free forest stand growth simulator, STEMS. The parameters were inferred using the sets of growth data obtained from stem analyses of 39 trees, chosen from 13 sample plots of the forest stands. The effects of thinning regimes on the patterns of stand growth and carbon absorption were investigated by simulating the stand growth patterns of the case study stand with 3 different thinning regimes: no-thinning, early thinning with low intensity and late thinning with high intensity using the simulator. According to the results of the analyses, the different thinning regimes cause significant effects on the growth patterns of average DBH, average height, diameter distribution and stand volume as well as the amount of carbon absorptions.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.484-490
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• 2013

This study was conducted to develop a simulation model for estimating the amount of such products as round wood, dimension lumber and the residual wood biomass produced by processing the individual trees of Larix kaempferi. In the model, the stem volume is assessed using the taper equations of the species to estimate the stem forms. Then, the model simulates the conversion processes of logs to round wood or lumber and assesses the maximum amount of the wood products by the lumber dimensions or round wood size. Also the model provides information on the amount of residuals for kerf and slabs produced on the conversion processes for sawn timber or round wood. According to the results of an application of the model to a L. kaempferi process, the trees greater than 12 cm of DBH can be converted to logs for lumber or round wood production. For the trees, of which DBH is available for log conversion, the maximum amount of final products by dimensions were analyzed. In this analysis, production of the bigger dimension lumber was assumed to be preferred to that of the smaller or round wood. This model can be used for assesment of forest economic value through estimation of merchantable volume for the trees, and assessment of mill residues which has the potential to provide significant amount of feedstock for bioenergy production as well.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.223-230
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• 2020

Central Asia has great growth potential for cooperation as the Korean Official Development Assistance (ODA) program expands and diversifies. In the case of the forest sector, Korea's successful greening experience has attracted interest from countries in Central Asia. In particular, the depletion of the Aral Sea and a widespread environmental degradation should motivate regional cooperation as well as highlights the need to establish a multilateral cooperative system. The limitation of existing bilateral cooperation, which is the limitation of South-South cooperation, is underscored by the engagement of new donors or the multilateral cooperation and triangular cooperation of organizations is receiving new attention. In addition, Central Asia is suitable for implementing the basic concepts of triangular cooperation. Korea is able to make complementary regional agreements using friendly partnerships with Kazakhstan (the Emerging Donor) and Uzbekistan (the second South Korean Focus Country of ODA). To reinterpret the basic concept of triangular cooperation, three regional cooperation strategies for Central Asia are proposed in this study: windbreak forest development to guarantee resident settlement, resident income increase, and protection of the Aral Sea from further degradation.

• Korean Journal of Biological Psychiatry
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• v.20 no.2
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• pp.54-60
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• 2013

Objectives The purpose of this study is to find the influential clinical and physical characteristics which affect apnea-hypopnea index (AHI) in suspected obstructive sleep apnea (OSA) patients. Methods We evaluated the comprehensive factors including sleep related symptoms, clinical scales, medical history, substance use, and anthropometric data of the 119 participants who complained of the symptoms of OSA. All the participants underwent attended-full night laboratory polysomnography. The correlation and multiple regression analysis were conducted to find the influential and predictive factors of AHI. Results A multiple linear regression model 1 showed that higher AHI was associated with higher body mass index (BMI)(p < 0.001) and higher frequency of observed apnea (p = 0.002). In multiple linear regression model 2, AHI was associated with higher BMI (p < 0.001) and loudness of snoring (p = 0.018). Conclusions The present preliminary results suggest that BMI and observed apnea are most influential factors that affect AHI in suspected OSA patients. In the future study we will design the prediction formula for the OSA and AHI, which is useful in the clinical medical field.

• Investigative Magnetic Resonance Imaging
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• v.5 no.1
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• pp.49-56
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• 2001

Purpose : To evaluate value of superparamagnetic iron oxide (SPIO) as a negative oral contrast agent in MR cholangiopancreatography (MRCP). Materials and methods : Forty-eight patients with suspected biliary tract or pancreatic diseases and six healthy volunteers were enrolled in this study. All MR images were obtained using a 1.5 T MR unit. MR-CP using fat-suppressed half-Fourier acquisition single-shot turbo spin echo (HASTE) and turbo spin echo (TSE) techniques were performed and reconstructed with maximal intensity projection (MIP). To determine the most optimal concentration of SPIO to obliterate the high signal intensity of water, a phantom experiment was conducted with various concentrations of SPIO-water mixture. Two radiologists evaluated pre- and postcontrast MRCPS. The contrast enhancement was assessed on the basis of loss of signal intensity in the stomach and duodenum. Results : In the phantom experiment, a significant increase of percentage of signal intensity loss (PSIL) occurred in concentration of 22.4 ugFe/ml (Feridex1 ml diluted with water 500 ml). Postcontrast MRCP showed an improved image quality compared with precontrast images. The rate of improvement in the diagnosis of diseases of the common bile duct and pancreatic duct was 25% (12/48). Conclusion : In patients with suspected biliary tract and pancreatic diseases, the SPIO is useful as a negative oral contrast agent for MRCP and provides an improvement of image quality.

• The Korean Journal of Nuclear Medicine
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• v.9 no.2
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• pp.23-28
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• 1975

Glucose tolerance, insulin and growth hormone responses following glucose or amino acids administration by means of parenteral or oral load were studied in patients with far advanced gastric cancer. Hormone responses following nutrients load showed in patients with gastric cancer were compared to those of healthy subjects. Results were as follows: 1. Blood sugar appearance following oral glucose administration was diminished in patients with far advanced gastric cancer. 2. The insulin responses of gastric cancer following oral glucose were also diminished as compared to that of normal subjects and were identical with parenteral route. 3. Parenteral administration of glucose or amino acids to patients with gastric cancer result ed in a increase of plasma growth hormone level. 4. Lower insulin response to amino acids was observed on parenteral administration in patient with gastric cancer as in healthy subjects. 5. Author discussed that the low insulin response after oral glucose administration showed in gastric cancer, and any additional insulin requirement arise when longer periods of parenteral amino acid administration are necessary, as in the patient with malnutritions.

• Explosives and Blasting
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• v.28 no.1
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• pp.27-39
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• 2010

Blast design equations based on the concept of scaled distances can be obtained from the statistical analysis on measured peak particle velocity data of ground vibrations. These equations represents the minimum scale distance of various recommendations for safe blasting. Two types of scaled distance widely used in Korea are the square root scaled distance (SRSD) and cube root scaled distance (CRSD). Thus, the design equations have the forms of $D/\sqrt{W}{\geq}30m/kg^{1/2}$ and $D/\sqrt[3]{W}{\geq}60m/kg^{1/3}$ in the cases of SRSD and CRSD, respectively. With these equations and known distance, we can calculate the maximum charge weight per delay that can assure the safety of nearby structures against ground vibrations. The maximum charge weights per delay, however, are in the orders of $W=O(D^2)$ and $W=O(D^3)$ for SRSD and CRSD, respectively. So, compared with SRSD, the maximum charge for CRSD increases without bound especially after the intersection point of these two charge functions despite of the similar goodness of fits. To prevent structural damage that may be caused by the excessive charge in the case of CRSD, we suggest that CRSD be used within a specified distance slightly beyond the intersection point. The exact limit is up to the point, beyond which the charge difference of SRSD and CRSD begins to exceed the maximum difference between the two within the intersection point.

• Journal of Science Education
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• v.36 no.2
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• pp.329-340
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• 2012

The purpose of this study is to analyze the terms which were described in panels for astronomic article on exhibition at the Gwacheon National Science Museum, and to clarify that the terms were appropriate and easily understandable or not. In research, totally, 965 terms were collected in 52 panels(14 panels in planetarium, 17 panels in national history part, and 21 panels in traditional science part). All terms were categorized to 4types, as 1.Standard/Scientific terms, 2.Non-Standard/Scientific terms, 3.Standard/Non-Scientific terms, 4. Non-Standanrd/Non-Scientific casual words, based on 'Dictionary of Standard Korean' and 'Terminology of Astronomy'. And questionnaires survey was done to 24 in-service teachers at elementary school, middle school, and high school to clarify that the level of the terms are appropriate to students. The results of this study show that accurate scientific terms were 68.5%, and many of students had difficulty in understanding those scientific terms in the panels because of unfamiliarity. Therefore, in order to make students get more interest and better understanding, it is proposed to minimize scientific terms and to substitute them to casual terms which were related with practical life.

• Journal of Science Education
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• v.35 no.2
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• pp.149-158
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• 2011

The purpose of this study is to improve education program for Informal Science Education Institution by analyzing education program of Natural History Museum, one of informal science education institution. This research subject is Seodaemun Museum of Natural History, located in Seodaemun-Gu, Seoul. It is Public Natural History Museum, which runs more than 60 education programs every year continuously for recent 6 years. Objects of this study are 32 education programs for 3rd to 6th grade of elementary school. The result of study shows that teaching materials of programs, run by informal science education institution, don't contain enough script and activity for improving creativity and inquiring mind. As the result of the study, it is required that guidance plan of education program be developed with more activities, teaching method and script, to seek quality of class than quantity of that when developing education program of science education institutes. And it is required to develop teaching material using creative technique and to improve medium and long term program for development of feedback.