• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.127-137
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• 2007

To confirm whether or not the Electrochemical Disinfection System (EDS) meet with the D-2 regulation established by IMO (International Maritime Organization), the biological treatment efficacy of the EDS was assessed using three groups of natural marine plankton (bacteria, $10-50\;{\mu}m$ and $>50\;{\mu}m$ sized organisms). Influent water was passed through the EDS under the flow velocity ($23.8\;m^3/hr$) and test design was consisted of control (no treatment) and experimental (10 ppm and 30 ppm) condition for total residual chlorine (TRC). And the biological condition of the influent water followed the standards established by the guidelines for the approval of ballast water management systems. The disinfection efficacy of the $10-50\;{\mu}m$ sized organisms (phytoplankton) was assessed by three kinds of measurements using photomicroscope, epifluorescence microscope and fluorometer (fumer Designs 10-AU). After being passed through the EDS, all motile phytoplankton lost their motility under photomicroscope, the colour of chlorophyll fluorescence fumed from red into green under epifluorescence, and the high chlorophyll fluorescence (Expt. 1: 6.95, Expt. 2: 7.11) detected by fluorometer decreased into value not detected. These results indicated phytoplankton community was totally killed after electrochemical disinfection treatment. Survivorship of the larger organisms than $50\;{\mu}m$ was determined based on the appendage's movement under a stereomicroscope. Natural assemblage collected from ambient seawater was killed shortly after being passed through the EDS, whereas some Artemia remained alive. However, no live Artemia was found after 24 hour further exposure to each TRC concentration (10 and 30 ppm) under darkness. After electrochemical treatment, the target bacteria such as aerobes, coliform and Escherichia coli were completely killed on the basis of CFU (colony forming unit) on Petrifilm plate ($3\;M^{TM}$) after 48 hr incubation. Moreover, no regrowth was found in the three groups of plankton during five days under additional exposure to the treated water. These results indicated that the disinfection efficiency of the EDS on the three groups of plankton satisfy D-2 regulation.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.2
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• pp.139-155
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• 2009

Objective : To assess the biological stability of immediate transmucosal placement of tapered implants into tooth extraction sockets. Material and methods : Following tooth extraction, tapered implants were immediately placed into the sockets. Teeth with evidence of acute periapical pathology were excluded. After implant placement, sutured allowing a non-submerged, transmucosal healing. Standardized radiographs were obtained every visiting from baseline to 32 weeks after implant placment. Changes in depth of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD) were assessed. Results : Thirteen patients (10 males and 3 females) were enrolled and followed. They contributed with 15 tapered implants. extraction iste displayed sufficient residual bone volume to allow primary stability of all implants. The mean surgery time was $41{\pm}10.0$ mins. All implants healed uneventfully yielding a survival rate of 100%. Mean ISQ values were relatively stable. Interproximal crestal bone decreased $1.69{\pm}1.2mm$ (mesial), $1.65{\pm}1.2mm$ (distal) from baseline to 32-week follow-up. No statistically significant changes with respect to FMPS, FMBS, PPD and width of KG were observed. Conclusions: Immediate transmucosal implant placement represented a predictable treatment option for the replacement of teeth lost due to reasons including fractures, endodontic failures and caries.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.537-545
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• 1995

Quality changes of lettuce were studied during storage to investigate the efficiency, cooling properties and the washing and storage effects of immersion-type hydrocooling. As a result of plotting the nondimensionalized lettuce temperature versus cooling time, its cooling rate coefficient was shown to be $-0.365\;min^{-1}{\sim}-0.255\;min^{-1}\;(R^2=0.99{\sim}0.88)$. Rate of weight loss was not significantly (p>0.05) different between lettuces with various treatment conditions during storage at $5^{\circ}C$. However, during storage at $15^{\circ}C$, weight loss of hydrocooled lettuce was lower than that of non-treated lettuce after from 10 to 15 days. Especially, The lettuce packed with PE was more effective than that packed with try in terms of packing condition after hydrocooling. Lettuce pretreated with sterilizing agent, packed with PE vinyl film, removed residual water after hydrocooling had lower decaying rate than any other lettuces. Changes of L and b values in hydrocooled lettuce were slower than those of non-treated one. During changes of chlorophyll content, the initial value, $115.7{\sim}147.3\;mg%$ was decreased to $50{\sim}60%$ after 25 days of storage at $5^{\circ}C$ and within 15 days of storage at $15^{\circ}C$. It could be presumed that the addition of sterilizing agent reduced the initial level of overall total and coliform count and its growth rate during storage. The respiration rate of hydrocooled lettuce at $5^{\circ}C$ was $23.95\;mg{\cdot}CO_2/kg\;hr$, which is 10% of those of non-treated lettuce.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.155-162
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• 2008

The Welsh onion beet armyworm, Spodoptera exigua (Hubner), has attacked Welsh onion and is now the most important pest of Welsh onion in southwestern Korea. The beet armyworm has a wide host range, occurring as a serious pest of vegetable and fields. The relatively high abundance of beet armyworm has stimulated frequent application of insecticides to foliage. Insecticide resistance is a major problem in management of this insect. Accordingly, pesticide application for the control of beet armyworm was tried in both the open field and in laboratory, using 4 synthetic compounds such as metaflumizone and chlorfenapyr, indoxacarb, flufenoxuron, emamectin benzoate. In the laboratory, each developmental stages from eggs, larva to pupa was tested against 4 insecticides. Against the eggs of welsh onion beet armyworm, there was no significantly different with each other. These tested chemicals no killing effect to eggs. However, the population of 1st larva hatched from eggs were reduced because they eaten the egg shell with residual insecticides. The tested insecticides were taken very high mortalities to 1st to 3rd larva of Welsh onion beet armyworm. Otherwise, there were decreased the death rate from 4th to 6th larva. On the other hand, their value of control effects were relatively good against Welsh onion beet armyworms in the field between 87.2 and 90.5% on 10 days after insecticide application.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.76-90
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• 2018

To determine the distribution of mercury (Hg) in the coastal surface sediments around the Korean peninsula, the baseline concentration of Hg was estimated, the extent of contamination was assessed, and the factors controlling the distribution were discussed. The concentrations of Hg in surface sediments were significantly high in Jinhae-Masan Bay in the South Sea, Ulsan-Onsan Bay and Yeongil Bay in the East Sea, but Hg in other sediments showed a similar distribution to Cs and relatively very low concentration between 0.21 and $39.5{\mu}g/kg$ ($13.6{\pm}7.80{\mu}g/kg$). Compared to the sediment quality guidelines in Korea, 8 % of the surface sediments (n=282) analyzed in this study exceeded the values of the threshold effects level (TEL), and six sediments collected around Onsan Port were higher than the value of the probable effects level (PEL). The contamination levels of Hg were assessed by the enrichment factors using the baseline concentration (2.06Cs+1.75) based on the residual analysis from the linear regression line for Cs, and further, factors controlling the distribution of Hg were discussed by the comparison with geochemical substances depending upon the Hg enrichment level. Hg concentrations were correlated well with Cs concentration in the range of less than 1.69 of EF implying grain size control, while in the range of 1.69 and 4.03 Hg concentrations were correlated well with Fe oxyhyroxide and organic carbon contents, which indicates Hg was enriched by superior sorption capability. On the meanwhile, samples with higher EFs (4.03 to 74.9) showed fairly positive correlations with other metals (Cu, Zn, Pb) rather than geochemical substances. For samples in Youngil Bay and Ulsan-Onsan Bay (n=30), Hg concentrations were correlated only with other metals rather than geochemical substances implying simultaneous supply of metal particles from metal refineries. But samples at Gosung, Sokcho and Uljin coast were correlated well with organic carbon even though they had high EFs. In addition, samples in Jinhae-Masan Bay with high contents of S were enriched by relatively high sulfide formation.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.477-484
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• 2017

This study was conducted to investigate the content of sulfur dioxide, carotenoids and the degree of contamination of Bacillus cereus in 33 kinds of dried sweet potato from domestic mainly dried agricultural products in Korea. According to the characteristics of dried sweet potato samples, it was classified into four clusters and as a result of analyzing the contents of sulfur dioxide, carotenoids and the degree of contamination B. cereus was no significant difference among the clusters. The detection ranges of residual sulfur dioxide from 33 dried sweet potatoes ranged from 0.38 to 28.16 mg/kg, three cases (9.09%) were detected at the reference level of 10 mg/kg or more. But no samples exceeding 30 mg/kg, the tolerance level of sulfur dioxide in dried sweet potatoes were detected. Since dried sweet potato does not have a standard for carotenoids, when comparing the national and international standards of carotenoids, the range of detection of carotenoids in dried sweet potato was $46{\sim}2,663{\mu}g$/100 g, which was within the reference range of $0{\sim}9,826{\mu}g$/100 g. In principle colonies suspected to be B. cereus in dried sweet potato were not detected. In 7 cases (21.21%), there were detected in the range of 0.05~1.59 log CFU/g but not more than 3 log CFU/g as the reference value. The results of this study are expected to be used as basic data to establish quality standard for dried sweet potatoes. In order to control the quality of dried sweet potatoes in domestic market, raw materials, drying method and packaging after distribution, it is necessary to maintain and maintain the process steadily.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.409-415
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• 2022

Plant growth and development are also affected by root-zone environment. Therefore, it is important to consider the variables of the root-zone environment when establishing an irrigation strategy. The purpose of this study is to analyze the relationship between the volumetric moisture content (VWC), Bulk EC (ECb), and Pore EC (ECp) used by plant roots using FDR sensors in two types of rockwool media with different water transmission characteristics, using the method above this was used to establish a method for collecting and correcting available root-zone environmental data. For the experiment, two types of rockwool medium (RW1, RW2) with different physical characteristics were used. The moisture content (MC) and ECb were measured using an FDR sensor, ECp was measured after extracting the residual nutrient solution from the medium using a disposable syringe in the center of the medium at a volumetric moisture content (VWC) of 10-100%. Then, ECb and ECp are measured by supplying nutrient solution having different concentration (distilled water, 0.5-5.0) to two types of media (RW1, RW2) in each volume water content range (0 to 100%). The relationship between ECb and ECp in RW1 and RW2 media is best suited for cubic polynomial. The relationship between ECb and ECp according to volume moisture content (VWC) range showed a large error rate in the low volume moisture content (VWC) range of 10-60%. The correlation between the sensor measured value (ECb) and the ECp used by plant roots according to the volumetric water content (VWC) range was the most suitable for the Paraboloid equation in both media (RW1, RW2). The coefficient of determination the calibration equation for RW1 and RW2 media were 0.936, 0.947, respectively.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.150-164
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• 2022

This study was conducted to provide basic information for the development of silvicultural guidelines and manuals. This was achieved through analysis of tree and stand characteristics according to the first and second thinning in Korean white pine plantations. Data were collected from permanent plots installed at Korean white pine plantations according to thinning intensity, and residual tree and stand variables, including diameter at breast height (DBH), volume, and mortality at age 19-43, were analyzed using data repeatedly collected in 4-5 measurements by experiments. According to one-way variance of analysis, tree DBH and volume were significantly different according to thinning intensity (p<0.05). DBH distribution was skewed to the left side over time as thinning intensity was heavier. Thus, tree DBH values were larger in heavy thinning plots with increased age. The periodic annual increment (PAI) of DBH was higher with heavier thinning intensity and fewer years after thinning. The PAI range by thinning intensity was 0.48-0.95 cm/year at age 19-24. In addition, the PAI increased in heavy thinning plots after the second thinning; The PAI range by thinning intensity was 0.29-0.67 cm/year after the second thinning at age 37-42. The PAI of tree volume differed according to thinning intensity, and the PAI value did not decrease obviously, in contrast to the pattern of the DBH PAI. Stand volume was generally higher in high-density stands, and the PAI of stand volume was high in unthinned and light thinning plots. Mortality was highest in unthinned plots, and the differences in mortality according to thinning intensity increased over time. Consequently, the growth of DBH and tree volume was lower as stand density increased, but this growth was facilitated with appropriate first and second thinning operations.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.13-28
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• 2023

This study assessed the biochemical methane potential (B_u-P) of three grass species-Poa pratensis (PP), Zoysia japonica (ZJ), and Agrostis stolonifera (AS). B_u-P values were determined as 0.330 Nm³/kg-VS_added for PP, 0.297 Nm³/kg-VS_added for ZJ, and 0.261 Nm³/kg-VS_added for AS. Notably, PP exhibited superior suitability for methane production. The investigation also examined the impact of silage storage duration on PP grass clippings, revealing a 19% decline in B_u-P from an initial value of 0.269 Nm³/kg-VS_added on day 0 to 0.217 Nm³/kg-VS_added on day 180. Throughout the storage period, there were significant increases in neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) contents, rising from 67.59%, 39.68%, and 3.02% on day 0 to 77.12%, 54.65%, and 6.24% on day 180, respectively. These findings highlight the influence of storage duration on the anaerobic digestibility of PP grass clippings. To effectively utilize grass clippings as a renewable resource for methane production, further studies considering factors such as initial moisture content, pretreatment methods, and potential effects of residual pesticides are necessary to optimize anaerobic digestion efficiency for herbaceous biomass.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.22-31
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• 2005

Purpose : To conduct a nationwide survey on the principals in radiotherapy for rectal cancer, and produce a database of Korean Patterns of Care Study. Materials and Methods : We developed web-based Patterns of Care Study system and a national survey was conducted using random sampling based on power allocation methods. Eligible patients were who had postoperative radiotherapy for rectal cancer without gross residual tumor after surgical resection and without previous history of other cancer and radiotherapy to pelvis. Data of patients were Inputted to the web based PCS system by each investigators in 19 institutions. Results : Informations on 309 patients with rectal cancer who received radiotherapy between 1998 and 1999 were collected. Male to female ratio was 59 : 41, and the most common location of tumor was lower rectum ($46\%$). Preoperative CEA was checked in $79\%$ of cases and its value was higher than 6 ng/ml in $32\%$. Pathologic stage were I in $1.5\%$, II in $32\%$, III in $53\%$, and IV in $1.6\%$. Low anterior resection was the most common type of surgery and complete resection was peformed in $95\%$ of cases. Distal resection margin was less than 2 cm in $30\%$, and number of lymph node dissected was less than 12 in $31\%$. Chemotherapy was peformed in $91\%$ and most common regimen was 5-FU and leucovorine ($59\%$). The most common type of field arrangement used for the initial pelvic field was the four field box (Posterior-Right-Left) technique ($65.0\%$), and there was no AP-PA parallel opposing field used. Patient position was prone in $81.2\%$, and the boost field was used in $61.8\%$. To displace bowel outward, pressure modulating devices or bladder filling was used in $40.1\%$. Radiation dose was prescribed to isocenter in $45.3\%$ and to isodose line in 123 cases ($39.8\%$). Percent delivered dose over $90\%$ was achieved in $92.9\%$. Conclusion : We could find the Patterns of Care for the radiotherapy in Korean rectal cancer patients was similar to that of US national survey. The type of surgery and the regimen of chemotherapy were variable according to institutions and the variations of radiation dose and field arrangement were within acceptable range.