• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.4
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• pp.184-191
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• 2010

Epiphytic diatoms are very important organisms in the seagrass ecosystem because their colonization on leaves increases microtopography and provides attachment sites that make the leaves more hospitable for other epiphytes. Epiphytic diatoms were attached to the leaves in the following 3 manners: (1) parallel to the cells of the seagrass leaf or by molding the shape of the diatom along the cell shape of the leaf; (2) with increasing diatom density toward the leaf tip; (3) Cocconeis species as attaching species than the Naviculoid species as the second attaching species on the leaf tip. In addition, the epiphytic diatom communities on Zostera marina leaves differed from those on the Zostera japonica leaves, but were very similar to the epiphytic communities on Zostera caespitosa leaves. Our results suggest that the epiphytic community on seagrass leaves varied according to the leaf shape such as leaf length and width, but the leaf cell shape or size did not influence the dynamics of the diatom communities.

• Korean Journal of Medicinal Crop Science
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• v.12 no.1
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• pp.43-46
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• 2004

In genus Angelica, three species have been used and cultivated for medicinal material in orient, A. gigas in Korea, acutiloba in Japan and sinensis in China. A. gigas (Chamdangui) is different from A. acutiloba or A. sinensis in the contents chemical components and their efficacious. In Korea, in particular, A. acutiloba has been cultivated in a small acreage from several decades ago, and recently A. sinensis has been trying to cultivate. A trial of adaptation and cultivation of the three species was performed in different altitudinal regions such as Suwon (50 m of sea level), Jinbu (500 m of sea level) and Taebak (700 m of sea level). A. gigas and acutiloba grew and produced roots successfully at all locations, but A. sinensis could grow only at high altitudinal region, Taebaek. A. sinensis survived 70.3% at Taebaek, but only 45.2% at Jinbu and 3.6% at Suwon. The dry root yield of A. sinensis was as low as 1,600 kg/ha at Taebaek and 1,270 kg/ha at Jinbu comparing farmers' average root yield of A. gigas, 3,000 kg/ha however, no root could be harvested at Suwon. The results, showed it was that A. sinensis could not grow at low altitudinal plane area except high altitude area in Korea. Even though it could grow, the root yield was too low to support the income.

• Korean Journal of Medicinal Crop Science
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• v.12 no.1
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• pp.60-66
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• 2004

This study was carried out to confirm the phylogenetic relationships in Korean Rhus species. Sequences from internal transcribed spacers (ITS) of nuclear ribosomal DNA and rbcL gene of chloroplast DNA were determined. Cotinus coggygria was selected as outgroup because it is closest allied with Rhus in Anacardiaceae. Also, ingroup was limited as six Korean Rhus species. ITS 1 sequences in six species of Rhus and one species of Cotinus ranged from 246 to 253 bp and ITS 2 sequences from 234 to 244 bp. Concerning the G+C content of the studied taxa, ITS 1 sequences ranged from 58.0 to 68.13% and ITS 2 from 59.75 to 68.46%. On the other hand, rbcL sequences were same size in the all species examined by 1,428 bp. G+C contents of rbcL sequences were ranged from 43.56 to 43.77% which means there are nearly no different from interspecies each other. Phylogenetic tree strongly supports the colse relationships between R. succedanea and R. sylvestris. Rhus javanica and Cotinus coggygria were also closely allied with each other in ITS and rbcL trees. Therefore, R. javanica was regarded as most primitive species among the Korean Rhus species. ITS 1 region of nuclear ribosomal DNA was suggested as very useful taxonomical marker for genus Rhus.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.314-322
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• 2017

Purpose: This study was conducted to investigate the hot air drying characteristics of squash slices depending on the drying conditions (input air velocity, input air temperature, and sample thickness). Methods: The developed drying system was equipped with a controllable air blower and electric finned heater, drying chamber, and ventilation fan. Squash (summer squash called Korean zucchini) samples were cut into slices of two different thicknesses (5 and 10 mm). These were then dried at two different input air temperatures (60 and $70^{\circ}C$) and air velocities (5 and 7 m/s). Six well-known drying models were tested to describe the experimental drying data. A non-linear regression analysis was applied to determine model constants and statistical indices such as the coefficient of determination ($R^2$), reduced chi-square (${\chi}^2$), and root mean square error (RMSE). In addition, the effective moisture diffusivity ($D_{eff}$) was estimated based on the curve of ln(MR) versus drying time. Results: The results clearly showed that drying time decreased with an increase in input air temperature. Slice thickness also affected the drying time. Air velocity had a greater influence on drying time at $70^{\circ}C$ than at $60^{\circ}C$ for both thicknesses. All drying models accurately described the drying curve of squash slices regardless of slice thickness and drying conditions; the Modified Henderson and Pabis model had the best performance with the highest R2 and the lowest RMSE values. The effective moisture diffusivity ($D_{eff}$) changes, obtained from Fick's diffusion method, were between $1.67{\times}10^{-10}$ and $7.01{\times}10^{-10}m^2/s$. The moisture diffusivity was increased with an increase in input air temperature, velocity, and thickness. Conclusions: The drying time of squash slices varied depending on input temperature, velocity, and thickness of slices. The further study is necessary to figure out optimal drying condition for squash slices with retaining its original quality.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.4
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• pp.11-23
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• 2018

The purpose of this study is to identify the ecological characteristics and biological interactions between species of the abandoned rice paddy field in mountainous areas and to suggest a management strategy for stable food chain formation and biodiversity enhancement. The study site is located in Uldae wetland of Songchu district Bukhansan National Park, site characteristics and biological habitat characteristics were identified through site survey and literature survey. With regard to physical environment, among geographical features, the Uldae Wetland and the neighborhood inside the basin was a gently sloping area($5{\sim}15^{\circ}$). And 64.0% of basin faced the north. With regard to water environment, the Uldae Wetland was wetland of rainfed paddy field depending on precipitation and the system of stream flowing into the wetland from valley. According to the results of examining flora in plant ecology, in general, they were herbaceous wetland species. 88.6% of existing plants inside the Uldae Wetland basin was a forest in the mountain. And Quercus spp. community and Pinus densiflora community accounted for 64.6% of that, and was dominant. Except for that, Salix koreensis community was distributed. The existing vegetation of Uldae Wetland inhabited wetland species and terrestrialization indicator species, and it was thought that partial terrestrialization inside the Uldae Wetland was in progress after the discontinuation of paddy cultivation, such as the expansion of Salix koreensis distribution area. In the status of appearing faunae in the Uldae Wetland with regard to wildbirds of appearing principal species, The Uldae wetland was based on a abandoned rice paddy field various wildlife, and was a wildlife feeding, spawning, and resting place. The water environment was an important factor in maintaining the wetland living creatures function, habitat of waterbirds and benthic macroinvertebrates, amphibians and odonate are spawning ground and habitat, it was affecting the vegetation ecosystem based on wetlands. In order to maintain the diversity of wildlife, it was important to maintain smooth water supply and water level. A stable food chain will be formed and the Uldae wetland biodiversity will be abundant by establishing the relationship between the species of Uldae wetland, which is abandoned rice paddy field, and the habitat environment favored by species belonging to the ecosystem stepwise linkage. The ecological characteristics of the Uldae wetlands and the relation between the species were analyzed and the environmental conditions were reflected in the planning and management plan of Uldae wetland ecology.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.24-29
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• 2012

A total of 187 samples of leafy vegetables and fruits were acquired at traditional markets and department stores in Seoul, Korea. Samples were tested for microorganism distributions and for the presence of pathogenic bacteria. The aerobic mesophilic counts ranged between 2.5 and 9.4 log CFU/g, with the highest count recorded from the dropwort. Counts of psychrotrophic microorganisms were as high as those of the mesophilic microorganisms. Total coliform populations between 1.0 and 7.8 log CFU/g were found in 90.9% of the samples. Microbiological counts for fruits were very low. $Escherichia$ $coli$ was isolated in 24 (12.8%) samples. $Staphylococcus$ $aureus$ and $Clostridium$ $perfringens$ contamination were found in 15 (8.0%) and 20 (10.7%) samples. $Salmonella$ species and $Listeria$ $monocytogenes$ were detected in 2.7 and 0.5% of samples, respectively. Among the total 187 samples, 8 samples were contaminated by more than two pathogens. $E.$ $coli$ O157:H7 was not detected in any of the samples. The microbial contamination levels determined in the present study may be used as the primary data to execute microbial risk assessment of fresh vegetables and fruits.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.143-147
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• 2009

A survey of food preservatives, sulfur dioxide and microbial contamination levels was conducted on 73 seasoned dried fishes(41 squids, 17 filleted fish, 6 Alaska pollack, 9 others) collected from domestic markets and internet. Among preservatives, only sorbic acid was detected in 25 samples including 23 seasoned dried squids, 1 seasoned filleted fish and 1 seasoned dried Alaska pollack with a range $0.01{\sim}0.92g/kg$. Sulfur dioxide was detected from one sample(seasoned dried squid) and its content was 10.5 mg/kg. All samples were contaminated by total aerobic bacteria, and the degree was $3.00{\sim}6.45\;log_{10}$ CFU/g(average level was $5.09\;log_{10}$ CFU/g). Escherichia coli, Salmonella spp. and Staphylococcus aureus were not detected in all samples. On the basis of the results above, most of the seasoned dried fishes were appropriate for Korea food standard, yet biological hygiene control will be needed constantly.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.98-107
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• 2017

A DNA profile database was constructed to investigate the genetic relatedness of 72 germplasm samples of Pyrus and related cultivars using microsatellite markers. Three P. pyrifolia, four P. commus, and one P. betulifolia cultivars with different morphological traits were screened using 387 pairs of microsatellite primers. A core set of 11 primer pairs was selected to obtain 133 polymorphic amplified fragments meeting three criteria: high polymorphism information contents (PIC), high repeatability, and distinct allele patterns. The number of alleles per locus ranged between 4 and 22. Average PIC was 0.743 (range: 0.557 - 0.879). Cluster analysis using the unweighted pair - group method with arithmetical average (UPGMA) separated the 72 pear cultivars and germplasm samples into four major groups: Chinese, European pears, and a cluster of 55 Asian pears that could be reclassify into two subcluster, I - $1^{st}$ and II - $2^{nd}$, according to pedigree information. Almost all of the cultivars were discriminated by 11 microsatellite marker genotypes. The microsatellite DNA profile database may be utilized as tool to verify distinctness, uniformity, and stability between candidate cultivar, and to verify in the distinctness of existing cultivars.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.262-267
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• 2014

To analyze the presence of microbes in organic farm produce, green chillies, lettuce, tomatoes, apples, pears, and rice were collected at 47 production sites with organic and conventional produce. Total average bacterial counts of 4.07 log CFU/g in organic green chillies, 3.71 log CFU/g in conventional green chillies, and 6.76- 6.90 log CFU/g in the both lettuce were detected. Mean bacterial counts of 4.48 log CFU/g and 2.84 log CFU/g were detected in organic and conventional pear produce, respectively. Differences in bacterial counts in tomatoes, apples, and rice in organic and conventional produce were less pronounced. Clostridium perfringens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were not detected in any produce sample. However, Bacillus cereus was detected with average counts of 1.04 log CFU/g in 11/47 (23%) conventional produce samples and 1.97 log CFU/g in 6/47 (13%) organic produce samples. Therefore, organic and conventional produce showed similar microbial prevalence patterns, and comparable safety in terms of pathogen contamination.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.75-79
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• 2001

Stem firmness and flowering response of cut lily as influenced by medium composition (Control; Upland soil, Pt; Peatmoss, Pe; Perilite, Ve; Vermiculite, Rrh; Rotted rice-hull, RPt: Russian Peatmoss) were studied. For 'Casa Blanca', plant height and length of flower stalk increased when bulbs were planted in Pt:Rrh:Ve (1:1:1, v.v$^{-1}$ ), and dried leaves of lower part plants decreased in RPt:Pe:Rrh (1:1:1, v.v$^{-1}$ ). In case of 'Marco Polo', plant height and length of lower stalk increased in Pt:Rrh (1:1, v.v$^{-1}$ ) as compared to other treatment, number of leaves and dried leaves increased when bulbs were planted in RPt:Pe:Rrh (1:1:1, v.v$^{-1}$ ) as compared to the control. Flowering of 'Casa Blanca' increased in RPt:Pe:Rrh (1:1:1, v.v$^{-1}$ ) as compared to the control and that o 'Marco Polo' increased when bulbs planted in Pt:Rrh(1:1, v.v$^{-1}$ ). Flower-bud blasting of both cultivars increased with Pt as compared. Stem firmness of 'Casa Blanca' increased in Pt:Pe:Ve (1:1:1, v.v$^{-1}$ ), and especially stem firmness of upper part plant of 'Marco Polo' increased in Pt:Rrh (1:1, v.v$^{-1}$ ) as compared to the control. Generally, stem firmness of 'Casa Blanca' was not influenced by the culture medium.