• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.33-38
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• 1976

As a basic studies for increasing food production utilizing sandy barren lands and sandy farmlands of low productivity which distributed widely in Korea, an experiment of growing rice-plant on sandy barren land was undertaken as follows. 1. Variety, IR-667 was adopted and the growing method was a nutrient-irrigation culture which aimed to minimize percolation loss in sand with an automatic contineous supplying nutrient solution for supplmenting the sand characteristics. 2. The growth type price-plant after heading was a typical higher yield plant, that is, numerous, small, narrow, and thickend leaves, straight attitute, dense fasciculated etc. though the rooting of plant after planting was delayed because of using paddy-field grown seedling. 3. The adaptability of rice-plants on sandy land seemed to be different by varieties and IR-667 was more adaptable than ordinary Japonica varieties. 4. Even at the period of heading and maturing, the root system of rice-plant grown on sand showed vigorous growth having more activated apical portions. while, even the lower leaves showed flourished state. 5. The suppling of calcium and magnecium in addition to nitrogen, phosphorus and potassium on sand made notable increase of stem number per plant, grain number per stem and yields.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.102-113
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• 2019

Slack-tide sampling was carried out at 6 stations at high and low tide for a tidal cycle during spring tide of the early summer (June) and summer (July, August) of 2016 to determine the difference of water quality according to tide in Masan Bay, Korea. The mixing regime of all the water quality components investigated was well explained through the correlation with SAL. In the early summer and summer, TURB, DSi and NNN which mainly flow into the bay from the streams and SS, COD, AMN and $H_2S$ which mainly indicate the internal sink and source materials have a property of conservative mixing and non-conservative mixing, respectively. The conservative mixing showed a good linear relationship of the water quality between high and low tide, and the non-conservative mixing showed a variation of different pattern each other. Factor analysis performed on the concentration difference data sets between high and low tide helped in identifying the principal latent variables for them. In early summer, multiple effects (tidal action, natural influx and internal sinks and sources etc.) acted in combination for the differences to be distributed evenly in four factors (VF1~4), since there were few allochthonous inputs as a low-water season. On the contrary, in summer, the parameters showing large concentration difference at ST-1 affected by stream water were concentrated in one factor (VF1) and clearly distinguished from the parameters affected by the internal sinks and sources. In fact, there is no estuary (bay) that always maintains steady state flow conditions. The mixing regime of an estuary might be changed at any time due to the change of flushing time, and furthermore the change of end-member conditions due to the internal sinks and sources makes the occurrence of concentration difference inevitable. Therefore, when investigating the water quality of the estuary, it is necessary to take a sampling method considering the tide to obtain average water quality data.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.447-460
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• 2022

It is well known that satellite synthetic aperture radar interferometry (InSAR) has been widely used for the observation of surface displacement owing to earthquakes, volcanoes, and subsidence very precisely. In wetlands where vegetation exists on the surface of the water, it is possible to create a water level change map with high spatial resolution over a wide area using the InSAR technique. Currently, a number of imaging radar satellites are in operation, and most of them support a ScanSAR mode observation to gather information over a large area at once. The Cienaga Grande de Santa Marta (CGSM) wetland, located in northern Colombia, is a vast wetland developed along the Caribbean coast. The CGSM wetlands face serious environmental threats from human activities such as reclamation for agricultural uses and residential purposes as well as natural causes such as sea level rise owing to climate change. Various restoration and protection plans have been conducted to conserve these invaluable environments in recognition of the ecological importance of the CGSM wetlands. Monitoring of water level changes in wetland is very important resources to understand the hydrologic characteristics and the in-situ water level gauge stations are usually utilized to measure the water level. Although it can provide very good temporal resolution of water level information, it is limited to fully understand flow pattern owing to its very coarse spatial resolution. In this study, we evaluate the L-band ALOS-2 PALSAR-2 ScanSAR mode to observe the water level change over the wide wetland area using the radar interferometric technique. In order to assess the quality of the interferometric product in the aspect of spatial resolution and coherence, we also utilized ALOS-2 PALSAR-2 stripmap high-resolution mode observations.

• Journal of the Korean Orthopaedic Association
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• v.56 no.2
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• pp.157-163
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• 2021

Purpose: Xanthomatosis of the Achilles tendons is rare. In some patients, however, the lesions in the Achilles tendon need to be removed, which may be painful and disfiguring. While studies of successful surgical outcomes for the total resection and reconstruction of the Achilles tendon have been reported, reconstruction surgery has a technical challenge, and extended surgical exposures are required. This study analyzed five cases of bilateral xanthoma of the Achilles tendon, which was treated surgically using a wedge-shaped tendon-sparing approach to eliminate the need for tendon reconstruction. Materials and Methods: From July 2010 to May 2018, five patients with xanthomatosis in both Achilles tendons underwent wedge-shaped tendon preserving surgery. The average age was 49 years (range, 40-55 years), and the follow-up period was 21.4 months (range, 12-31 months). The patients consisted of three males and two females. Complications related to surgery were recorded. The outcome measures included the range of motion of the ankle joint, American Orthopaedic Foot and ankle Society (AOFAS) ankle/hindfoot score, and visual analogue scale (VAS) for overall satisfaction at the last follow-up. The availability of a single-limb heel raise and returning time to work were also measured. Results: Wound dehiscence that did not require secondary surgery was noted in one patient. At the last follow-up, the range of motion of the ankle joint was normal in all patients. The mean AOFAS ankle/hindfoot score was 91 (range, 85-96) and the VAS for the overall satisfaction ranged from 8 to 10. The average time between surgery and return to work was 27.6 days (range, 17-58 days) and all patients could perform a single-limb heel raise test. Conclusion: The tendon-sparing technique, which can preserve the anatomical functioning of the Achilles tendon, could be an excellent surgical approach because it has very promising functional and cosmetic surgical outcomes in patients with Achilles tendon xanthomatosis.

• Pediatric Infection and Vaccine
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• v.28 no.3
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• pp.133-143
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• 2021

Purpose: This study aimed to determine the incidence of central line-associated bloodstream infection (CLABSI) in the neonatal intensive care unit (NICU), evaluate the patients' clinical characteristics, and identify the etiologic agents for guidance in prevention and treatment. Methods: A retrospective chart review study of infants classified as having CLABSI was conducted at the NICU of Seoul National University Bundang Hospital from January 2016 to December 2020. Results: Of the 45 infants, 53 had CLABSIs within a follow-up period of 18,622 catheter days. The incidence of CLABSIs was 2.85 per 1,000 catheter days. The most common catheter type was a peripherally inserted central catheter (n=47, 81%). A total of 57 pathogens were isolated, of which 57.9% (n=33) were Gram-positive bacteria, 36.8% (n=21) were Gram-negative bacteria, and 5.3% (n=3) were Candida spp. The most common pathogens were Staphylococcus aureus (n=12, 21%) and coagulase-negative staphylococci (n=12, 21%), followed by Klebsiella aerogenes (n=8, 14%). The median duration of bacteremia was 2 days, and 19 episodes showed bacteremia for 3 days or more. The mortality rate of infants within 14 days of CLABSI was 13.3% (n=6). Conclusions: This study analyzed the incidence of CLABSI and the distribution of pathogens in the NICU. Continuous monitoring of CLABSI based on active surveillance serves as guidance for empiric antibiotic use and also serves as a tool to assess the necessity for implementation of prevention strategies and their impact.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.51-60
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• 2022

Objectives: The purpose is to evaluate dosimetric performance and delivery efficiency of VMAT with Halcyon LINAC for double target spine SBRT Materials and Methods: 12 patients with spine oligometastases were retrospectively studied. Single-isocenter spine SBRT plans was established using Halcyon® with Dual Layer MLC and Truebeam® with High Definition MLC. All patients' plans were created in Eclipse TPS through the identical conditions and optimization. C.I, H.I, G.I (Gradient Index), maximal and volumetric doses to spinal cord and low dose area were evaluated for comparison of both plans. Also, total MU and BOT(Beam On Time) were evaluated. Results: Halcyon plans was no Statistical differences in C.I and H.I. However, the average of G.I was 4.64 for Halcyon, which decreased to 5.5% compared to Truebeam (P<0.001). Halcyon plans demonstrated statistically significant reduced G.I. The average of 50% and 25% isodose volume was 487.56 cc (-3.82%, P<0.001), 1859.45 cc (-4.75%, P<0.001) in Halcyon, respectively. Significantly reduced low dose spill were observed in Halcyon plans. In the evaluation of the spinal cord, the average of Dmean and V10 of Halcyon plans in the sample group with an overlap volume of less than 1 cc was 6.802 Gy (-3.504%, P=0.067), 5.766±1.683 cc (-8.199%, P=0.002), respectively. Halcyon plans demonstrated statistically significant reduced D_mean and V10. For delivery efficiency, MU and BOT(maximum dose rate for each machine), on average, increased in Halcyon plans. However, the average of BOT(800MU/min for each machine) was 648.33 sec for Halcyon (-1.74%, P<0.001). Conclusion: Halcyon plan for double-target spine SBRT demonstrated advantages in the low dose area with a steep dose gradient, while having dosimetrically equivalent target dose distribution and spinal cord protective effect. As a result, Halcyon LINAC produced a dosimetrically improved plan for double-target spine SBRT.

• Journal of Korean Dental Hygiene Science
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• v.7 no.1
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• pp.69-81
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• 2024

Background: This study aimed to investigate the association between physical activity and periodontitis based on depression status in a representative sample of Korean adults. Methods: A total of 12,689 subjects who participated in the 7th Korea National Health and Nutrition Examination Survey (2016-2018) were examined. Depression was defined as a PHQ-9 score ≥ 10. Periodontal status was assessed using the community periodontal index, with periodontitis defined as a code ≥ 3. Physical activity categories were divided into a physical activity group and a non-physical activity group, considering the number of days and minutes spent on moderate and vigorous activities. Moderate activity was defined as causing slight breathlessness or a slightly elevated heart rate, while vigorous activity was defined as causing significant breathlessness or a rapid heart rate. Multivariable logistic regression analyses were adjusted for sociodemographic variables (age, sex, education level, and household income), oral and general health behaviors (use of floss and interdental proximal brush, current smoking), and systemic health status (diabetes and hypertension). All analyses utilized a complex sampling design, and subgroup analysis was performed to estimate associations stratified by depression (PHQ-9 ≤ 9 and ≥ 10). Results: Multivariable regression analysis revealed that among participants with depression, those who did not engage in physical activity were 2.65 times more likely to have periodontitis (odds ratio = 2.65, 95% confidence interval = 1.17-6.01). Conclusion: The study findings suggest that individuals who participate in any form of physical activity may be significantly less likely to develop periodontitis, particularly within the group experiencing depression.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.4
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• pp.177-188
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• 1989

The purpose of this study was to investigate the detoxifying effect on PSP-infested sea mussel, Mytilus edulis, by heating treatment and correlation between the PSP toxicity and the environmental conditions of shellfish culture area such as temperature, pH, salinity, density of Protogonyaulax sp. and concentration of inorganic nutrients such as $NH_4-N,\;NO_3-N,\;NO_2-N\;and\;PO_4-P$. This experiment was carried out at $Suj\u{o}ng$ in Masan, Yangdo in Jindong, $Hach\u{o}ng\;in\;K\u{o}jedo\;and\;Gamch\u{o}n$ bay in Pusan from February to June in $1987\~1989$. It was observed that the detection ratio and toxicity of PSP in sea mussel were different by the year even same collected area. The PSP was often detected when the temperature of sea water about $8.0\~14.0^{\circ}C$. Sometimes the PSP fox of sea mussel was closely related to density of Protogonyaulax sp. at $Gamch\u{o}n$ bay in Pusan from March to April in 1989, but no relationship was observed except above duration during the study period. The concentration of inorganic nutrients effects on the growth of Protogonyaulax sp., then effects of $NO_3-N$ was the strongest among them. When the PSP-infested sea mussel homogenate was heated at various temperature, the PSP toxicity was not changed significantly at below $70^{\circ}C$ for 60 min. but it was proper-tionaly decreased as the heating temperature was increased. For example, when the sea mussel homogenate was heated at $100^{\circ}C,\;121^{\circ}C$ for 10 min., the toxicity was decreased about $67\%\;and\;90\%$, respectively. On the other hand, when shellstock sea mussel contained PSP of $150{\mu}g/100g$ was boiled at $100^{\circ}C$ for 30 min. with tap water, the toxicity was not detected by mouse assay, but that of PSP of $5400{\mu}g/100g$ was reduced to $57{\mu}g/100g$ even after boiling for 120 min.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.21-28
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• 1973

This report is prepared to promote cocoon natures for the use of silk reeling material. It is easily understandable that there must be disuniformity composed with superior group and inferior group in commercial silkworms. If such different groups be seperated by some method, it would be a great contribution for the cocoon production. For a comparative purpose, silkworm sex seperation carried out because male silkworms produce more silk than female worms. The author has developed a new chemical reagent available for the seperation of superior group and inferior group from commercial silkworms, which he has named it as Better Hybrid Controller (BHC). The obtained comparative results are summarized as followings. 1. Basic investigation of BHC application a) In case BHC applied with hybrid worms and pure line, the former one starts to adapt mulberry leaves earlyer than pure line variety. b) The mulberry adapting interval distribution of pure line worms after BHC application showed U type distribution, but hybrid worms showed L type or Poisson's distribution. c) In case of BHC application with silkworms, the longer period application is, the duller distribution was formed. d) When silkworms are seperated in two groups by use of BHC application, the earlyer mulberry adapted group is seemed as stronger than the other part and the group ratio is 2 : 1. 2. Comparation between sex seperation result and better hydrid control (BHC) seperation result. a) The cocoon shell per cent of male worm group showed betweer result than the female group but only 0.4% difference between sexes. b) The cocoon shell per cent of superior group, seperated by BHC, showed 0.7% more than the inferior group. c) The average cocoon shell per cent of BHC treated cocoons showed much more than the Control group as 1.6∼2.4% increase. Enven the inferior group showed better result than the Control. d) Such unexpected result is considered to be the result that BHC application is activating some thing with silkworm physiology. e) On the ether hand, the result of sexes seperated groups or male worm group did not show desirable conclusion as far as cocoon shell per cent is concerned. f) However, when the male group was reeled as silk, it showed much better silk yield or silk per cent of cocoon than the female group as much as one per cent difference between by sexes. Such result was brought by superior silk yield from cocoon shell as much as 87.4%. g) On the other hand, the male group showed lowest non breaking reelable ratio (63%) among all group comparation. h) When we compare cocoon qualities by sex seperation and BHC seperation against the Control, there is no qualitative change, but BHC group showed quantitative promotion with cocoon bave length as much as about hundred meters. i) In case of calculation for productive income of cocoon production, BHC applied group showed about ten per cent income promotion more than the Control. The sexes seperated group, however, showed rather negative result because the male cocoon produced poor weight per box eggs which could not cover it by the inclose of silk yield of it. j) So, the BHC application with the fetched worm stage brought about big promotion for cocoon production. k) BHC method may be used either for seperation purpose or quantitative promotion with whole silk-worms. 3. Only male silkworms rearing did not show desirable productivity, so there is no reason to work out it in the fetching stage of worm.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.133-137
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• 2010

Purpose: The main function of vitamin D is the mineralization of the brain by increase of calcium and phosphorus, in case it is insufficient in children, lime deposition on cartilage cannot occur so it leads to rachitis, and in adults, it leads to osteomalacia or osteoporosis. It is also strongly believed in the academic world that vitamin D can restrict the growth of cancer cells and prevent heart diseases, which is also somewhat proven in epidemiological researches. While the right density of vitamin D is still being studied, 20-32 ng/mL is believed to be the most ideal density. Therefore, I wanted analyze how much density of 25-Hydroxyvitamin D3 that Koreans possess. Materials and Methods: From February 20th, 2008 to April 21st, 2009, the collection of 2800 serums, from medical examination treated subjects by Neodin Medical Institute, have been tested. The targets were tested by 25-Hydroxyvitamin D (125I Kit: Diasorin, USA), and were analyzed by dividing into many different categories (gender, age, season, region). Results: The average density of male were 20 ng/mL, female 17.08 ng/mL. Per age groups, the density of males were as follows: 10~20-18 ng/mL, 21~30-17 ng/mL, 31~40-19 ng/mL, 41~50-21 ng/mL, 51~60-22 ng/mL, 61~70-22 ng/mL, 71~80-22 ng/mL and 81~90-19.9 ng/mL. Average density of females per age groups, were as follows: 10~20-16 ng/mL, 20~30-15.26 ng/mL, 30~40-16 ng/mL, 40~50-17 ng/mL, 50~60-19 ng/mL, 60~70-19 ng/mL, 70~80-19 ng/mL, and 80~90-17 ng/mL. Per seasons, From December to May, the subjects showed the density of 15.97 ng/mL, while from June to November, it showed 21.60 ng/mL. On density of males from January to April regionally, Seoul+Gyeonggi-Do-15.52 ng/mL, Gangwon-Do-15.33 ng/mL, Choongchung-Do-18.03 ng/mL, Jeonla-Do-18.68 ng/mL, Gyungsang-Do-18.76 ng/mL and Cheju Do-21.23 ng/mL. Conclusions: The vitamin D of Koreans is has been insufficient compared to the suggested amount. Ultraviolet rays, which is the main source of vitamin D is critical, therefore it is suggested that more outdoor activities can definitely help.