• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.35-47
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• 2018

A edible mushroom, Clitocybe maxima (Lentinus giganteusis) commercially cultivated in China and Taiwan. However, the researches of cultivation and cultural characteristics were not reported in Korea. In this study, we conducted on cultural characteristics and artificial cultivation of C. maxima. Six isolates were collected from China(3 isolates, commercial strain), Taiwan(1 isolate, commercial strain) and Korea(2 isolates, wild type). C. maxima and L. giganteus collected in China and Taiwan, respectively, are the same in China and are estimated to be of the same species as cultured characteristics. The mycelial growth of the collected strains was not significantly different in agar medium but it showed the best growth in YPMG in liquid culture. Optimum temperature for mycelial growth and induction of fruit body were 25℃ and 30℃, respectively. In order to artificial cultivation of C. maxima, cultural characteristics and artificial cultivation were carried out using agricultural by-products and forestry by-products materials. Mycelial growth was suitable in rice straw, cottonwood sawdust, corncob and rice seed medium, and it was selected as a cultivation medium. The suitable medium for artificial cultivation of C. maxima was selected to mixed medium 2(compounding ratio(v/v): 55% of hardwood sawdust, 5% of cottonseed pellets, 10% of cottonseed, 15% of beet pulp, 15% of swollen rice husks). It took about 30 days to be able to harvest, it was faster than oyster mushrooms. The cultivation period was about 30days. A isolate, CMA-002 was not initiation to fruit body primordiuma on the used cultivation substrate. Other 5 isolates were initiate and development to fruit body on the substrate used in this study. The strain CMA-003 was initiated to be fruiting body by 8~10 days after induction of fruiting body in all of the substrates. Isolate CMA-003 was generate to a bundle fruit body. Other isolates, however, were form fruit body individually. The CMA-003 strain was likely highly recommendable strains for farming. The optimum conditions for the induction and growth of C. maxima fruit body were 25~30℃, 8 hr illumination per day with white fluorescent lamp, 90~95% relative humidity, and 1,500 ppm of CO₂ concentration in a cultivation room.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.715-727
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• 2023

To provide detailed and appropriate meteorological information in mountainous areas, the Korea Forest Service has established an Automatic Mountain Meteorology Observation Station (AMOS) network in major mountainous regions since 2012, and 464 stations are currently operated. In this study, we proposed an optimal kriging technique with lapse rate correction to produce gridded temperature data suitable for Korean forests using AMOS point observations. First, the outliers of the AMOS temperature data were removed through statistical processing. Then, an optimized theoretical variogram, which best approximates the empirical variogram, was derived to perform the optimal kriging with lapse rate correction. A 500-meter resolution Kriging map for temperature was created to reflect the elevation variations in Korean mountainous terrain. A blind evaluation of the method using a spatially unbiased validation sample showed a correlation coefficient of 0.899 to 0.953 and an error of 0.933 to 1.230℃, indicating a slight accuracy improvement compared to regular kriging without lapse rate correction. However, the critical advantage of the proposed method is that it can appropriately represent the complex terrain of Korean forests, such as local variations in mountainous areas and coastal forests in Gangwon province and topographical differences in Jirisan and Naejangsan and their surrounding forests.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.24-38
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• 2024

Five species of plants (Pimpinella brachycarpa (Kom.) Nakai, Hylotelephium erythrostictum (Miq.) H. Ohba, Magnolia sieboldii K. Koch, Sanguisorba hakusanensis Makino, Agastache rugosa (Fisch. & Mey.) Kuntze) native to the clean area of Mt. Jiri were selected. The collection period was from May to September 2021, and the five species plants were collected in their native habitats with flowers in full bloom. The collected plants were extracted with 70% EtOH and 17 kinds of polyphenol components were analyzed. Next, flowers, leaves and roots were separated from plants, extracted with 70% EtOH for each part and experiments were conducted on DPPH, ABTS, total polyphenols, and total flavonoids. The results are as follows. 1. There were a total of 13 polyphenol components contained in the 5 species of plants native to Mt. Jiri. Among them, the total content of the most detected substance was Sanguisorba hakusanensis Makino, which was 126.2 ppm, and the main substance was ellagic acid (=ELA), which was 122.4 ppm. 2. As a result of examining the DPPH radical scavenging activity, the flowers, stems, and roots of Sanguisorba hakusanensis Makino showed the best scavenging activity, while the flower extracts of other plants showed good scavenging activity. 3. The highest ABTS radical scavenging activity was Sanguisorba hakusanensis Makino flower extract at 13.5 ㎍/㎖, followed by roots at 16.8 ㎍/㎖ and leaves at 22.6 ㎍/㎖;. Although such a large ABTS radical scavenging activity could not be confirmed in other plants, the flower extract was overall better than the leaf and root extracts of other parts. 4. The highest total polyphenol content was found in the leaves of Magnolia sieboldii K. Koch, at 161.4mg GAE/g, followed by the highest content in the roots of Magnolia sieboldii K. Koch and the roots of Agastache rugosa (Fisch. & Mey.) Kuntze, at 130.0mg GAE/g. Also, the lowest was found to be Sanguisorba hakusanensis Makino. 5. The total flavonoid content was 186.2mg CAE/g in the roots of Agastache rugosa (Fisch. & Mey.) Kuntze, 166.9mg CAE/g in the flowers, and the lowest was 116.1mg CAE/g in the leaves. As shown in the results above, Sanguisorba hakusanensis Makino has excellent antioxidant efficacy and has a high polyphenol content, so it is expected to be fully utilized in the cosmetics industry in the future.

• Applied Biological Chemistry
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• v.21 no.3
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• pp.150-184
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• 1978

Nutritional characteristics and physio-chemical properties of mycelial growth and fruitbody formation of oyster mushroom(Pleurotus ostreatus)in synthetic media, the curtural condition for the commerical production in the rice straw and poplar sawdust media, and the changes of the chemical components of the media and mushroom during the cultivation were investigated. The results can be summarized as follows: 1. Among the carbon sources mannitol and sucrose gave rapid mycelial growth and rapid formation of fruit-body with higher yield, while lactose and rhamnose gave no mycelial growth. Also, citric acid, succinic acid, ethyl alcohol and glycerol gave poor fruit-body formation, and acetic acid, formic acid, fumaric acid, n-butyl alcohol, n-propyl alcohol and iso-butyl alcohol inhibited mycelial growth. 2. Among the nitrogen sources peptone gave rapid mycelial growth and rapid formation of fruit-body with higher yield, while D,L-alanine, asparatic acid, glycine and serine gave very poor fruit-body formation, and nitrite nitrogens, L-tryptophan and L-tyrosine inhibited mycelial growth. Inorganic nitrogens and amino acids added to peptone were effective for fruit-body growth, and thus addition of ammonium sulfate, ammonium tartarate, D,L-alanine and L-leucine resulted in about 10% increase fruit-body yield. L-asparic acid about 15%, L-arginine about 20%, L-glutamic acid, and L-lysine about 25%. 3. At C/N ratio of 15.23 fruit-body formation was fast, but the yield decreased, and at C/N ratio of 11.42 fruit-body formation was slow, but the yield increased. Also, at the same C/N ratio the higher the concentration of mannitol and petone, the higher yield was produced. Thus, from the view point of both yield of fruit-body and time required for fruiting the optimum C/N ratio would be 30. 46. 4. Thiamine, potassium dihydrogen phosphate and magnecium sulfate at the concentration of $50{\mu}g%$. 0.2% and 0.02-0.03%, respectively, gave excellent mycelial and fruit-body growth. Among the micronutrients ferrous sulfate, zinc sulfate and manganese sulfate showed synergetic growth promoting effect but lack of manganese resulted in a little reduction in mycelial and fruit-body growth. The optimum concentrati on of each these nutrients was 0.02mg%. 5. Cytosine and indole acetic acid at 0.2-1mg% and 0.01mg%, respectively, increased amount of mycelia, but had no effect on yield of fruit-body. The other purine and pyrimidine bases and plant hormones also had no effect on mycelial and fruit-belly yield. 6. Illumination inhibited mycelial growth, but illumination during the latter part of vegetative growth induced primordia formation. The optimum light intensity and exposure time was 100 to 500 lux and 6-12 hours per day, respectively. Higher intensity of light was injurous, and in darkness only vegetative growth without primordia formation was continued. 7. The optimum temperature for mycelial growth was $25^{\circ}C$ and for fruit-body formation 10 to $15^{\circi}C$. The optimum pH range was from 5.0 to 6.5. The most excellent fry it-body formation were produced from the mycelium grown for 7 to 10 days. The lesser the volume of media, the more rapid the formation of fruit-body; and the lower the yield of fruit-body; and the more the volume of media, the slower the formation of fruit-body, and the higher the yield of fruit-body. The primordia formation was inhibited by $CO_2$. 8. The optimum moisture content for mycelial growth was over 70% in the bottle media of rice straw and poplar sawdust. 10% addition of rice bran to the media exhibited excellent mycelial growth and fruit-body formation, and the addition of calciumcarbonate alone was effective, but the addition of calcium carbonate was ineffective in the presence of rice bran. 9. In the cultivation experiments the total yield of mushroom from the rice straw media was $14.99kg/m^2$, and from the sawdust media $6.52kg/m^2$, 90% of which was produced from the first and second cropping period. The total yield from the rice straw media was about 2.3 times as high as that from the sawdust media. 10. Among the chemical components of the media little change was observed in the content of ash on the dry weight basis, and organic matter content decreased as the cultivation progressed. Moisture content, which was about 79% at the time of spawning, decreased a little during the period of mycelial propagation, after which no change was observed. 11. During the period from spawning to the fourth cropping about 16.7% of the dry matter, about 19.3% of organic matter, and about 40% of nitrogen were lost from the rice straw media; about 7.5% of dry mallet, about 7.6% of organic matter, and about 20% of nitrogen were lost from the sawdust media. For the production of 1kg of mushroom about 232g of organic matter and about 7.0g of nitrogen were consumed from the rice straw media; about 235g of organic matter and about 6.8g of nitrogen were consumed from the sawdust media, 1㎏ of mushroom from either of media contains 82.4 and 82.3g of organic matter and 5.6 and 5.4g of nitrogen, respectively. 12. Total nitrogen content of the two media decreased gradually as the cultivation progressed, and total loss of insoluble nitrogen was greater than that of soluble nitrogen. Content of amino nitrogen continued to increase up to the third cropping time, after which it decreased. 13. In the rice straw media 28.0 and 13.8% of the total pentosan and ${\alpha}$-cellulose, respectively, lost during the whole cultivation period was lost during the period of mycelial growth; in the sawdust media 24.1 and 11.9% of the total pentosan and ${\alpha}$-cellulose, respectively, was lost during the period of mycelial growth. Lignin content in the media began to decrease slightly from the second cropping time, while the content of reduced sugar, trehalose and mannitol continued to increase. C/N ratio of the rice straw media decreased from 33.2 at spawining to 30.0 at ending; that of the sawdust media decreased from 61.3 to 60.0. 14. In both media phosphorus, potassium, manganese and zinc decreased, at magnesium, calcium and copper showed irregular changes, and iron had a tendency to be increased. 15. Enzyme activities are much higher in the rice straw media than in the sawdust media. CMC saccharifying and liquefying activity gradually increased from after mycelial propagation to the second cropping, after which it decreased in both media. Xylanase activity rapidly and greatly increased during the second cropping period rather than the first period. At the start of the third cropping period the activity decreased rapidly in the rice straw media, which was not observed in the sawdust media. Protease activity was highest after mycelial propagation, after which it gradually decreased. The pH of the rice straw media decreased from 6.3 at spawning to 5.0 after fourth cropping; that of the sawdust media decreased from 5.7 to 4.9. 16. The contents of all the components except crude fibre of the mushroom from the rice straw media were higher than those from the sawdust media. Little change was observed in the content of the components of mushroom cropped from the first to the third period, but slight decrease was noticed at the fourth cropping.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.237-244
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• 2001

Purpose : To assess the tolerance, complete response rate, bladder preservation rate and survival rate in patients with muscle-invading bladder cancer treated with selective bladder preservation protocol. Method and Materials : From October 1990 to June 1998, twenty six patients with muscle-invading bladder cancer (clinical stage T2-4, N0-3, M0) were enrolled for the treatment protocol of bladder preservation. They were treated with maximal TURBT (transurethral resection of bladder tumor) and 2 cycles of MCV chemotherapy (methotrexate, crisplatin, and vinblastine) followed by $39.6\~45\;Gy$ pelvic irradiation with concomitant cisplatin. After complete urologic evaluation (biopsy or cytology), the patients who achieved complete response were planed for bladder preservation treatment and treated with consolidation cisplatin and radiotherapy (19.8 Gy). The patients who had incomplete response were planed to immediate radical cystectomy. If they refused radical cystectomy, they were treated either with TURBT followed by MCV or cisplatin chemotherapy and radiotherapy. The median follow-up duration is 49.5 months. Results : The Patients with stage T2-3a and T3b-4a underwent complete removal of tumor or gross tumor removal by TURBT, respectively. Twenty one out of 26 patients $(81\%)$ successfully completed the protocol of the planned chemo-radiotherapy. Seven patients had documented complete response. Six of them were treated with additional consolidation cisplatin and radiotherapy. One patient was treated with 2 cycles of MCV chemotherapy due to refusal of chemo-radiotherapy. Five of 7 complete responders had functioning tumor-free bladder. Fourteen patients of incomplete responders were further treated with one of the followings : radical cystectomy (1 patient), or TURBT and 2 cycles of MCV chemotherapy (3 patients), or cisplatin and radiotherapy (10 patients). Thirteen patients of them were not treated with planned radical cystectomy due to patients' refusal (9 patients) or underlying medical problems (4 patients). Among twenty one patients, 12 patients $(58\%)$ were alive with their preserved bladder, 8 patients died with the disease, 1 patient died of intercurrent disease. The 5 years actuarial survival rates according to CR and PR after MCV chemotherapy and cisplatin chemoradiotherapy were $80\%\;and\;14\%$, respectively (u=0.001). Conclusion : In selected patients with muscle-invading bladder cancer, the bladder preservation could be achieved by MCV chemotherapy and cisplatin chemo-radiotherapy. All patients tolerated well this bladder preservation protoco. The availability of complete TURBT and the responsibility of neoadjuvant chemotherapy and chemoradiotherapy were important predictors for bladder preservation and survival. The patients who had not achieved complete response after neoadjuvant chemotherapy and chemoradiotherapy should be immediate radical cystectomy. A randomized prospective trial might be essential to determine more accurate indications between cystectomy or bladder preservation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.40-46
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• 2013

The isotope ratios of $^{13}C/^{12}C$ and $^{18}O/^{16}O$ for a sample in a mass spectrometer are measured relative to those of a pure $CO_2$ reference gas (i.e., laboratory working standard). Thus, the calibration of a laboratory working standard gas to the international isotope scales (Pee Dee Belemnite (PDB) for ${\delta}^{13}C$ and Vienna Standard Mean Ocean Water (V-SMOW) for ${\delta}^{18}O$) is essential for comparisons between data sets obtained by other groups on other mass spectrometers. However, one often finds difficulties in getting well-calibrated standard gases, because of their production time and high price. Additional difficulty is that fractionation processes can occur inside the gas cylinder most likely due to pressure drop in long-term use. Therefore, studies on laboratory production of pure $CO_2$ isotope standard gas from stable solid calcium carbonate standard materials, have been performed. For this study, we propose a method to extract pure $CO_2$ gas without isotope fractionation from a solid calcium carbonate material. The method is similar to that suggested by Coplen et al., (1983), but is better optimized particularly to make a large amount of pure $CO_2$ gas from calcium carbonate material. The $CaCO_3$ releases $CO_2$ in reaction with 100% pure phosphoric acid at $25^{\circ}C$ in a custom designed, evacuated reaction vessel. Here we introduce optimal procedure, reaction conditions, and samples/reactants size for calcium carbonate-phosphoric acid reaction and also provide the details for extracting, purifying and collecting $CO_2$ gas out of the reaction vessel. The measurements for ${\delta}^{18}O$ and ${\delta}^{13}C$ of $CO_2$ were performed at Seoul National University using a stable isotope ratio mass spectrometer (VG Isotech, SIRA Series II) operated in dual-inlet mode. The entire analysis precisions for ${\delta}^{18}O$ and ${\delta}^{13}C$ were evaluated based on the standard deviations of multiple measurements on 15 separate samples of purified $CO_2$. The pure $CO_2$ samples were taken from 100-mg aliquots of a solid calcium carbonate (Solenhofen-ori $CaCO_3$) during 8-day experimental period. The multiple measurements yielded the $1{\sigma}$ precisions of ${\pm}0.01$‰ for ${\delta}^{13}C$ and ${\pm}0.05$‰ for ${\delta}^{18}O$, comparable to the internal instrumental precisions of SIRA. Therefore, we conclude the method proposed in this study can serve as a way to produce an accurate secondary and/or laboratory $CO_2$ standard gas. We hope this study helps resolve difficulties in placing a laboratory working standard onto the international isotope scales and does make accurate comparisons with other data sets from other groups.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.53-69
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• 2011

Vision and voice-based technologies are commonly utilized for human-robot interaction. But it is widely recognized that the performance of vision and voice-based interaction systems is deteriorated by a large margin in the real-world situations due to environmental and user variances. Human users need to be very cooperative to get reasonable performance, which significantly limits the usability of the vision and voice-based human-robot interaction technologies. As a result, touch screens are still the major medium of human-robot interaction for the real-world applications. To empower the usability of robots for various services, alternative interaction technologies should be developed to complement the problems of vision and voice-based technologies. In this paper, we propose the use of accelerometer-based gesture interface as one of the alternative technologies, because accelerometers are effective in detecting the movements of human body, while their performance is not limited by environmental contexts such as lighting conditions or camera's field-of-view. Moreover, accelerometers are widely available nowadays in many mobile devices. We tackle the problem of classifying acceleration signal patterns of 26 English alphabets, which is one of the essential repertoires for the realization of education services based on robots. Recognizing 26 English handwriting patterns based on accelerometers is a very difficult task to take over because of its large scale of pattern classes and the complexity of each pattern. The most difficult problem that has been undertaken which is similar to our problem was recognizing acceleration signal patterns of 10 handwritten digits. Most previous studies dealt with pattern sets of 8~10 simple and easily distinguishable gestures that are useful for controlling home appliances, computer applications, robots etc. Good features are essential for the success of pattern recognition. To promote the discriminative power upon complex English alphabet patterns, we extracted 'motion trajectories' out of input acceleration signal and used them as the main feature. Investigative experiments showed that classifiers based on trajectory performed 3%~5% better than those with raw features e.g. acceleration signal itself or statistical figures. To minimize the distortion of trajectories, we applied a simple but effective set of smoothing filters and band-pass filters. It is well known that acceleration patterns for the same gesture is very different among different performers. To tackle the problem, online incremental learning is applied for our system to make it adaptive to the users' distinctive motion properties. Our system is based on instance-based learning (IBL) where each training sample is memorized as a reference pattern. Brute-force incremental learning in IBL continuously accumulates reference patterns, which is a problem because it not only slows down the classification but also downgrades the recall performance. Regarding the latter phenomenon, we observed a tendency that as the number of reference patterns grows, some reference patterns contribute more to the false positive classification. Thus, we devised an algorithm for optimizing the reference pattern set based on the positive and negative contribution of each reference pattern. The algorithm is performed periodically to remove reference patterns that have a very low positive contribution or a high negative contribution. Experiments were performed on 6500 gesture patterns collected from 50 adults of 30~50 years old. Each alphabet was performed 5 times per participant using $Nintendo{(R)}$ $Wii^{TM}$ remote. Acceleration signal was sampled in 100hz on 3 axes. Mean recall rate for all the alphabets was 95.48%. Some alphabets recorded very low recall rate and exhibited very high pairwise confusion rate. Major confusion pairs are D(88%) and P(74%), I(81%) and U(75%), N(88%) and W(100%). Though W was recalled perfectly, it contributed much to the false positive classification of N. By comparison with major previous results from VTT (96% for 8 control gestures), CMU (97% for 10 control gestures) and Samsung Electronics(97% for 10 digits and a control gesture), we could find that the performance of our system is superior regarding the number of pattern classes and the complexity of patterns. Using our gesture interaction system, we conducted 2 case studies of robot-based edutainment services. The services were implemented on various robot platforms and mobile devices including $iPhone^{TM}$. The participating children exhibited improved concentration and active reaction on the service with our gesture interface. To prove the effectiveness of our gesture interface, a test was taken by the children after experiencing an English teaching service. The test result showed that those who played with the gesture interface-based robot content marked 10% better score than those with conventional teaching. We conclude that the accelerometer-based gesture interface is a promising technology for flourishing real-world robot-based services and content by complementing the limits of today's conventional interfaces e.g. touch screen, vision and voice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.42-56
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• 2005

Hyperlipidemia is one of the risk factors for coronary artery disease. Despite of epidemiological evidence that tea consumption is associated with the reduced risk of coronary heart disease, experimental studies designed to show that drinking tea affects blood lipid concentration or oxidative stress have been unsuccessful. The purpose of this study was to investigate whether functional tea (three servings/day) supplement with medical nutrition therapy (MNT) lead to a beneficial outcomes in mildly hyperlipidemic adults. From February to October, 2003, the 43 hyperlipidemic (23 men, 20 women) subjects (total cholesterol$\geq$200 mg/dL or triglyceride$\geq$150 mg/dL) admitted to K Medical Center were studied. Subjects were randomly divided into 3 groups; placebo tea (PT), half dose of functional tea (HFT), full dose of functional tea (FFT). During 12 weeks of study period, the subjects were given placebo or functional tea daily with MNT. Anthropometric measurements, blood chemical analysis including lipid levels, total superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, and dietary assessment were carried out at the beginning and end of experiment. The effects of functional tea were compared with the placebo in randomized clinical trial study. The placebo was prepared to match with the functional tea in color and taste. After the 12 weeks of MNT, the subjects had regular and balanced meal pattern. Consumption of foods high in cholesterol and saturated fat, salty foods, fried foods, and instant foods decreased significantly in all three groups (p<0.05). Intake of energy and cholesterol also decreased (p<0.05). Drinking three servings per day (390 mL/day) of functional tea significantly reduced the levels of blood triglyceride (HFT, 42.5%; FFT, 29.4%), total cholesterol (HFT, 8.5%; FFT, 13.7%), and atherogenic index (HFT, 14.6%; FFT, 21.7%). Whereas no changes were found in the LDL-, HDL-cholesterollevels, and LDL/HDL ratio. Plasma homocysteine (Hcy) concentration decreased significantly (p<0.05) in functional tea groups (HFT, 14.9%; FFT, 14.1%). SOD increased significantly (p<0.05) in HFT (8.3%). GSH-Px increased significantly (p<0.05) in FFT (12.8%). In conclusion, the MNT improved the dietary habits, in addition, functional tea supplement decreased blood lipid levels and Hcy, and increased SOD and GSH-Px levels. These results indicate that functional tea consumption may decrease the risk of cardiovascular disease via improving blood lipid levels and antioxidant status.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.227-237
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• 2008

Arsenic has recently become of the most serious environmental concerns, and the worldwide regulation of arsenic fur drinking water has been reinforced. Arsenic contaminated groundwater and soil have been frequently revealed as well, and arsenic contamination and its treatment and measures have been domestically raised as one of the most important environmental issues. Arsenic behavior in geo-environment is principally affected by oxides and clay minerals, and particularly iron (oxy)hydroxides have been well known to be most effective in controlling arsenic. Among a number of iron (oxy)hydroxides, for this reason, 2-line ferrihydrite was selected in this study to investigate its effect on arsenic behavior. Adsorption of 2-line ferrihydrite was characterized and compared between As(III) and As(V) which are known to be the most ubiquitous species among arsenic forms in natural environment. Two-line ferrihydrite synthesized in the lab as the adsorbent of arsenic had $10\sim200$ nm for diameter, $247m^{2}/g$ for specific surface area, and 8.2 for pH of zero charge, and those representative properties of 2-line ferrihydrite appeared to be greatly suitable to be used as adsorbent of arsenic. The experimental results on equilibrium adsorption indicate that As(III) showed much stronger adsorption affinity onto 2-line ferrihydrite than As(V). In addition, the maximum adsorptions of As(III) and As(V) were observed at pH 7.0 and 2.0, respectively. In particular, the adsorption of As(III) did not show any difference between pH conditions, except for pH 12.2. On the contrary, the As(V) adsorption was remarkably decreased with increase in pH. The results obtained from the detailed experiments investigating pH effect on arsenic adsorption show that As(III) adsorption increased up to pH 8.0 and dramatically decreased above pH 9.2. In case of As(V), its adsorption steadily decreased with increase in pH. The reason the adsorption characteristics became totally different depending on arsenic species is attributed to the fact that chemical speciation of arsenic and surface charge of 2-line ferrihydrite are significantly affected by pH, and it is speculated that those composite phenomena cause the difference in adsorption between As(III) and As(V). From the view point of adsorption kinetics, adsorption of arsenic species onto 2-line ferrihydrite was investigated to be mostly completed within the duration of 2 hours. Among the kinetic models proposed so for, power function and elovich model were evaluated to be the most suitable ones which can simulate adsorption kinetics of two kinds of arsenic species onto 2-line ferrihydrite.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.3
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• pp.2322-2341
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• 1971

The studies were conducted to determine the methods of irrigation control which is not only able to save the irrigation water as a adaptable measures for the insufficient irrigation water and the drought but also increase the yields of rice, in the paddy field which shows over percolating tendency through the couple years of 1968 and 1969 at Suwon. These experiments were carried with late maturing rice variety, Norim No. 6 and the major treatments in this experiments were filling the clay under surface soil, periodic irrigation and lining the Vinyl under the surface soil and three replicated completely randomized design was employed. Results obtained will be summarzed as follows. 1. Through the couple years, the plots tilled the clay under 15cm of the surface soil saved the irrigation water by 364% to 45% and 78% to 88% respectively. Particulary, the plot of filling the clay with 9cm thick under 15cm of the surface soil, saved the amount of irrigation water by 45% to 88% and also increased yields by 12% to 20% through the couple years. 2. The plots in which amount of 40mm of irrigation water is irrigated periodically from 5 to 8 days at the stages of tillering and ripening, saved theamount of irrigation water by 41% to 55% and also increased yields by 10% to 16% respectively through the couple years. 3. The plot lined the Vinyl under 15cm of the surface soil, saved the amount of irrigation water by 75% to 88% in accordance with the size of hole. The plot of lining the Vinyl with $3cm/m^2$ hole yielded almost same as the check plot, but in the case of lesser hole than above yielded less. 4. The plots inserted the Vinyl paper in 57cm depth and with 6cm height from the soil surface around the plot to prevent the ridge percolation reduced the amount of percolation by 25% to 33%. 5. The plot filled the wheat straw with 6cm thick under 15cm of the surface soil increased yields by 30% in former year but opposite results were gained in later year. 6. Generally, yields and yield components such as number of spikes of spikes per hill and number of grains per spike were decreased in 1969. These faots are considered to depend upon the rainy and cold weather in the stages of vigorous tillering and less sunshine in the stages of ripening. 7. The variation of characters among the plots will be summarized as follows. (1) Tallerplant height was found in the plots of clay filling and irrigation control. (2) longer culm length and higher yields were founds in the plots filled the clay with 9cm thick and controled the irrigation periodically froir 7 to 8 days. (3) Length of spike increased generally with yields but opposite tendency was found also. (4) Number of spikes per hill increased with yields in the plots of irrigation control. (5) Number of grains per spike increased with yields in the plots filled the clay with 9cm thick and controled irrigation periodically from 5 to 8 days. (6) Tendency of variation of 1000 grain weight is similar to Number of grains per spike. (7) Percentage of complete grains increased in the plot of clay filling and irrigation control.