• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.67-78
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• 2007

This study was carried out to monitor feed-nutritional components, toxic heavy metals (Cd, Pb and As) and pesticide residues through three cultivation stages (1st initial culture stage, 2nd mycelial growth stage, and 3rd fruit body-harvested stage) of king oyster mushroom (Pleurotus eryngii) produced by bottle type cultivation and oyster mushroom (Pleurotus osteratus) produced by vinyl bag type cultivation. For both cultivation types, compared with the initial culture, the weight reduction rate in spent mushroom substrates (SMS) after fruit body harvest was 29% for total wet mass, 21～25% for dry and organic matters and 19 ～22% for neutral detergent fiber. Two thirds to 3/4 of organic matter degraded and utilized by mycelia and fruit bodies was originated from fiber, of which the primary source (50～70%) was hemicellulose. The effect of mycelial growth stage on chemical compositional change in culture was little (P>0.05) for bottle type cultivation of king oyster mushroom but considerable (P<0.05) for vinyl type cultivation of oyster mushroom. Culture nutrients uptake by fruit bodies was very active for the bottle type cultivation. Compared with SMS, harvested fruit bodies (mushrooms) contained higher (P<0.05) crude protein, non-fibrous carbohydrate, and crude ash and lower (P<0.05) neutral detergent fiber. Regardless of stages, no culture samples were contaminated with toxic heavy metals and pesticide residues. In conclusion, the increase of fiber (neutral and acid detergent fibers) and indigestible protein contents and the decrease of true protein content in SMS indicated that the feed-nutritional value of SMS was significantly reduced compared with that of the initial culture and they were safe from toxic heavy metals and pesticide residues.

• Journal of the Mineralogical Society of Korea
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• v.30 no.3
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• pp.93-102
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• 2017

Heavy mineral provide an important information for sediment provenance as well as a potential submarine mineral resources. We compared the heavy mineral characteristics between Southeastern Yellow Sea Mud (SEYSM) and Southwestern Cheju Island Mud (SWCIM) surface sediments. We separated heavy minerals from 28 surface sediments in each mudbelt, and then carried out stereo-microscopic, field-emission scanning electron microscopic, energy dispersive spectroscopic and electron probe microanalysis to characterize the type, abundance, mineralogical properties and distribution pattern of heavy mineral. Amphibole and epidote, which are two major heavy minerals, account for more than 70% of total heavy minerals. Zircon and sphene contents are more abundant in SEYSM, whereas apatite and rutile contents are more abundant in SWCIM. Monazite only occurs in some area of SEYSM. Sphene and monazite content decrease to the south in SEYSM. Both garnet-zircon index (GZi) and rutile-zircon index (RuZi) are low in SEYSM but high in SWCIM. Amphiboles in SEYSM primarily correspond to hornblende, however those in SWCIM represent variable composition from pargasite, tshermakite, hornblende to tremolite. Garnets in SEYSM have high Mg and low Ca, but those in SWCIM have low Mg with variable Ca. Different heavy mineral characteristics between SEYSM and SWCIM suggests that sediments in each mudbelt have different provenances. Although this study implies that SEYSM sediment may mostly come from nearby Korean western rivers such as the Keum and Han rivers, this study does not suggest any idea of the source area of SWCIM sediment. Further study is needed to interpret the provenance and transportation mechanism of mudbelt sediments through the heavy mineral research for the river sediments flowing into the Yellow Sea and much more marine sediments.

• Journal of the Mineralogical Society of Korea
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• v.28 no.3
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• pp.245-253
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• 2015

The performance of $TiO_2$ photo-catalytic oxidation process is significantly dependent on the amount of hydroxyl radicals produced during the process, and it is an essential prerequisite to quantify its production. However, precise and accurate methods for quantification of hydroxyl radicals have not been developed so far. For this reason, this study was initiated to compare existing methods for analysis of hydroxyl radicals produced by $TiO_2$ photo-catalytic oxidation and to propose a new method to overcome the limitation of established methods. To simulate $TiO_2$ photo-catalytic oxidation process, Degussa P25 which has been widely used as a standard $TiO_2$ photo-catalyst was used with the dose of 0.05 g/L. The light source of process was UVC mercury low-pressure lamp (11 W, $2,975mW/cm^2$). The results indicate that both potassium iodide (KI)/UV-vis spectrometer and terephthalic acid (TPA)/fluorescence spectrometer methods could be applied to qualitatively measure hydroxyl radicals via detection of triiodide ion ($I_3{^-}$) and 2-hydroxyterephthalic acid which are produced by reactions of iodine ion ($I^-$) and TPA with hydroxyl radicals, respectively. However, it was possible to quantitatively measure hydroxyl radicals using TPA method coupled with high-performance liquid chromatograph (HPLC). The analytical results using TPA/HPLC method show that hydroxyl radical of 0.013 M was produced after 8 hours operation of photo-catalytic oxidation under specific experimental conditions of this study. The proposed method is expected to contribute to precise the evaluation of the performance of photo-catalytic oxidation process.

• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.171-187
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• 2006

The status of heavy metal contamination was investigated using chemical analyses of stream waters and sediments obtained from Samsanjeil and Sambong Cu mining area in Goseong-gun, Gyeongsangnam-do. In addition, the degree and the environmental risk of heavy metal contamination in stream sediments was assessed through pollution index (Pl) and danger index (DI) based on total digestion by aqua regia and fractionation of heavy metal contaminants by sequential extraction, respectively. Not only the degree of heavy metal contamination was significantly higher in Samsanjeil area than in Sambong area, but its environmental risk was also revealed much more serious in Samsanjeil area than in Sambong area. The differences in status and level of contamination and environmental risk between both two mining areas may be attributed to existence of contamination source and geology. Acid mine drainage is continuously discharged and flows into the stream in Samsanjeil mining area, and it makes the heavy metal contamination in the stream more deteriorated than in Sambong mining area in which acid mine drainage is not produced. In addition, the geology of Samsanjeil mining area is mainly comprised of andesitic rocks including a small amount of calcite and having lower pH buffering capacity fer acid mine drainage, and it is likely that the heavy metal contamination cannot be naturally attenuated in streams. On the contrary, the main geology of Sambong mining area consists of pyroclastic sedimentary Goseong formation containing a high content of carbonates, particularly calcite, and it seems that these carbonates of high pH buffering capacity prevent the heavy metal contamination from proceeding downstream in stream within that area.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.1
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• pp.3293-3301
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• 1974

An experimental work was conducted by using a laboratory-made model dryer to investigate the effect of the rate of natural forced-air on the drying rate of rough rice which was deposited in the deep-bed. The dryer consisted of 8 cylinderical containers with grain holding screen at their bottoms, each of which having 30cm in diameter and 15cm in height. The containers were sacked vertically with keeping them air-tight by using paper tape during dryer operation. Two separate layers of containers were operated in the same time to have two replications. The moisture contents of grains within each bins after predetermined period of dryer operation were determined indirectly by measuring the weight of the individual containers. The air-rates were maintained at 6 levels, or 5, 8, 10, 15, 18 and 20 millimenters of static head of water. The roomair conditions during dryer operation were maintained in the range of 10-l5$^{\circ}C$ in temperature and 40-60% in relative humidity. The results of the study are summarized as follows: 1. Drying characteristics of the grains in the bottom layers were approximately the same regardless of airdelivery rates, giving the average drying rate as about 0.35 percent per hour after 40-hour drying period, during which moisture content (w. b.) reduced from 24 percent to about 10 percent. 2. After about 40-hour drying period, the mean drying rates increased from 0.163 percent per hour to 0.263 percent per hour as air-flow rates increased from 5mm to 87.16mm of static head of water. In the same time, the moisture differences of grains between lower and upper layers varied from 12.7 percent at the air rate of 5mm of water head to 7.5 percent at the air-flow rate of 20mn of water head. Thus, the greater the air-flow rate was, the more overall improvement in drying performance was. Additionally, from the result of ineffectiveness of drying grain positioned at 70cm depth or above by the air rate of 5mm of static head of water it may be suggested in practical application that the height of grain deposit would be maintained adequately within the limits of air-rates that may be actually delivered. 3. Drying after layer-turning operation was continued for about 30 hours to test the effectiveness of reducing moisture differences in the thick layers. As a result of this layer-turning operation, moisture distribution through layers approached to narrow ranges, giving the moisture range as about 7 percent at air-flow rate of 5mm head of water, about 3 percent at 10mm head about 2 percent at 15mm head, and less than 1 percent at 20mm head. In addition, from the desirable results that drying rate was rapid in the lower layers and dully in the upper layers, layer-turning operation may be very effective in natural air drying with deep-layer grain deposit, especially when the forced air was kept in low rate. 4. Even though the high rate of air delivery is very desirable for deep-layer natural-air drying of rough rice, it can be happened that the required air delivery rate could not be attained because of limitation of power source available on farms. To give a guide line for the practical application, the power required to perform the drying with the specified air rate was analyzed for different sizes of drying bin and is given in Table (5). If a farmer selects a motor of which size is 1 or {{{{1 { 1} over {2 } }}}} H.P. and air-delivery rate which ranges from 8~10mm of head, the diameter of grain bin may be suggested to choose about 2.4m, also power tiller or other moderate size of prime motor may be recommended when the diameter of grain bin is about 5.0m or more for about 120cm grain deposit.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.59-68
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• 1996

This study investigated the enzyme histochemical localization and characteristics of lactate (LDH) and malate dehydrogenase (MDH) related with the oxidation-reduction metabolism in the sparganum and adult of 5. erinacei. By enzyme histochemical assay, activity of LDH was strong in the tegument and subtegumental muscle layers of the adult and sparganum. Activity of MDH was strong in the tegument of the sparganum and subtegumental muscle layers of the adult. However it was weak in the tegument of the adult. By electrophoresis, 45 kDa band was major and common in LDH of adults and spargana. The 150 kDa molecule was the major and common band in MDH of adults and r -spargana (from experimentally infected rats) . By isoelectrofocusing, isoelectric points (Pl) or 4 MDH isogyme from adult worm were 6.0.6.5, 6.7 and 7.1, respectively. Pl 6.0 was the major band. The active range of pH for MDH was about pH 6-8 and the optimum pH was pH 7 The effective temperature on the MDH was about $30^{\circ}C$∼$50^{\circ}C$ and the optimum temperature was about 40℃ in spargana md adult worm. In the stability against heat, when MDH was heated at 85℃ for 10 seconds, the activity was denatured perfectly. Maximum activity or MDH was 19.4 unit in the s-sparganum (from snakes), 24.5 unit in the r-sparganum (from rats) and 108.0 unit in the adult worm. The maximum activity was higher in adults than in spargana. The present result showed us that the nutrients absorbed through the tegument were transferred into inner tissues and were utilized as the source of metabolism. According to the habitat of the parasite, the isozymes of LDH and MDH are activated differently, and by this different activation the sparganum and adult can adapt themselves to parasitic circumstances.

• Journal of Life Science
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• v.25 no.4
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• pp.433-440
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• 2015

Several studies suggest that regular consumption of walnuts may have beneficial effects against oxidative stress-mediated disease such as cancer. The present study reports the total phenolic and flavonoid contents, together with the antioxidant and antibacterial activities of several solvent extracts (methanol, n-hexane, ethyl acetate, n-butanol, and water) obtained from walnut (Juglans regia L.) green husk. MIC (minimal inhibitory concentration) values of the walnut extracts for 8 human pathogenic bacteria strain were determined using agar dilution method. Antioxidant activity of extracts were assessed using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) assays, EC₅₀ of DPPH and ABTS scavenging activities, and determination of total phenolic and flavonoid content and its correlation with DPPH and ABTS scavenging capacities. Among the six extracts, ethyl acetate extract (EtOAc Ex) showed the highest antimicrobial activity at 3.2 mg/ml of MICs against Staphylococcus aureus SG511. Total flavonoids and polyphenol contents of EtOAc Ex were 42.48 mg of quercetin equivalents (QE)/g and 223.25 mg of gallic acid equivalents (GAE)/g respectively. The highest antioxidative potential was shown by the sample extracted with EtOAc Ex (EC₅₀=13.43 μg/ml for DPPH and EC₅₀=41.83 μg/ml for ABTS radical scavenging activity assay). These results showed that J. regia green husk extracts can be used as an easily accessible source of natural antibacterial agents and natural antioxidants.

• Korean Journal of Organic Agriculture
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• v.18 no.2
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• pp.257-269
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• 2010

To investigate the possibility of discrimination between organic and non-organic rice using stable isotope nitrogen of natural abundance, organic rice of 17 samples and non-organic rice of 13 samples grown at adjoining organic rice field were collected in 2008. Rice was grinded into brown rice, milled rice and hull, and samples were analysed for nitrogen and $\delta^{15}N$ at NICEM. Authors also made inquiries about N source for both farmers who conduct organic- and non-organic rice cultivation. In order to know whether the $\delta^{15}N$ can be used in discrimination between organic and non-organic rice, discriminant analysis were made with SPSS and logistic method. 1. Organic farmers used manure, rice bran, used mushroom culture, fermented fertilizer (company products), and oil cake, but non-organic farmers applied compound fertilizer. Rice straws were remained in organic rice field while moved out in non-organic field. 2. There were difference in $\delta^{15}N$ among organic rice and its byproduct(7.760????% in hull, 6.720????% in rice), but significant difference was not found between them. And the trend was same between province. Non-organic rice showed similar results. 3. Significant difference of $\delta^{15}N$ were found between organic rice and non-organic rice (p<0.01) and between hull of organic rice and that of non-organic rice hull (p<0.05). $\delta^{15}N$ seemed to be useful criteria for discrimination of organic and non-organic rice. 4. When applied discrimination analysis of SPSS and logistic, there were significant difference between organic rice, non-organic rice and its byproducts except brown rice and hull in SPSS method. Hull can be used as the most useful component for unknown sample prediction with 83.3% probability.

• Journal of Life Science
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• v.32 no.12
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• pp.919-928
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• 2022

As seen in the COVID-19 pandemic, unexpected emergence of new viruses presents serious concern on public health. Especially, the absence of effective vaccines or antiviral drugs against emerging viruses significantly increases the severity of disease and duration of viral circulation among population. Natural products have served as a major source for safe and effective antiviral drugs. In this study, we examined the virucidal activity of medical herb extracts with a view to discover novel antiviral agents with desired levels of safety and antiviral efficacy. Ethanol extracts of ten selected medical herbs were tested for antioxidant activity and in-vitro cytotoxicity in various animal cell lines. Of note, the herbal extracts showed broad and potent virucidal activities against rotavirus, hepatitis A virus, and influenza A virus. The extracts of Sorbus commixta and Glycyrrhiza uralensis showed strong virucidal activities against influenza A virus. We also examined whether the extracts of Sorbus commixta and Glycyrrhiza uralensis can be used as inactivating agents to prepare an inactivated viral vaccine. In a mouse model, influenza A virus inactivated by the extracts elicited high levels of neutralizing antibodies, and the vaccination provided complete protection against lethal challenge. These results suggest that herb-derived natural products can be developed to antiviral drugs as well as inactivating agents for preparation of inactivated viral vaccines.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.1-20
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• 1972

The trend and achievements of forest genetics research in abroad were investigated through observation tours and reference work and following facts were found to be important aspects which should be adopted in the forest genetics research program in Korea. Because of world wide recognization on the urgency of taking a measure to reserve some areas of the representative forest type on the globe before the extingtion of such forest type as the results of continuous exploitations of the natural forests to meet the timber demand all over the world, it is urgently needed to take a measure to reserve certain areas of natural stand of Pinus koraiensis, Pinus parviflora, Pinus densiflora f. erectra, Abies koreana, Quercus sp., Populus sp., etc. as gene pool to be used for the future program of forest tree improvement. And the genetic studies of those natural forest of economic tree species are also to be performed. 1. Increase of the number of selected tree for breeding purpose. Because of the fact that the number of plus tree at present is too small to carry out selection program for tree improvement, particularly for the formation of source population for recurrent selection of parent trees of the 2nd generation seed orchard it is to be strongly emphasized to increase the number of plus tree by alleviating selection criteria in order to enlarge the population size of plus trees to make the selection program more efficient. 2. Progeny testing More stress should be placed on carrying out progeny testing of selected trees with open pollinated seeds. And particular efforts are to be made for conducting studies on adult/juvenile correlation of important traits with a view to enable to predict adult performances with some traits revealed in juvenile age thus to save time for progeny testing. 3. Genotype-environment interaction Studies on genotype and environment interaction should be conducted in order to elucidate whether the plus trees selected on the good site express their superiority on the poor site or not and how the environment affect the genotype. And the justification of present classification of seed distribution area should be examined. 4. Seed orchard of broad leaf tree species. Due to the difficulty of accurate comparison of growth rate of neighbouring trees of broad leaf tree species in natural stand, it is recommended that for the improvement of broad leaf trees a seedling seed orchard is to be made by roguing the progeny test plantation planted densely with control pollinated seedlings of selected trees. 5. Breeding for insect resistant varieties. In the light of the fact that the resistant characteristics against insect such as pine gall midge (Thiecodiplosis japonensis U. et I.) and pine bark beetle (Myelophilus pinipera L.) are highly correlated with the amount and quality of resin which are known as gene controlled characteristics, breeding for insect resistance should be carried out. 6. Breeding for timber properties. With the tree species for pulp wood in particular, emphasis should be placed upon breeding for high specific gravity of timber. 7. Introduction of Cryptomeria and Japanese Cypress In the light of the fact that the major clones of Cryptomeria are originated from Yoshino source and are being planted up to considerably north and high elevation in Japan, those species should be examined on their cold resistance in Korea by planting them in further northern part of the country.