• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.422-424
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• 2002

The accuracy of DXA(Dual Energy X-ray Absorptiometry) highly depends on the detection and separation capability of dual energy X-ray X-ray photons. In addition both of scan time and patient exposure are affected by detection efficiency. A CZT detector with a good energy resolution and high detection efficiency was evaluated for the application of bone densitometry. Its performance was compared to a photomultiplier tube with a NaI(T1) scintillator in terms of energy resolution, detection efficiency and the accuracy of bone mineral density measurement. The comparison study was performed with CZT detector and PM tube using DXA equipments(OSTEO Plus, OSTEO Prima, ISOL Technology). The energy spectrum was acquired using MCA(Multi-Channel Analyzer). The used X-ray energy ranged from 20keV to 86keV. The MCA result of the CZT detector showed a slightly sharper energy spectrum than that of NaI(T1). Detection efficiency of the CZT detector at 59.5keV was 1.4 times better. Remarkably the final results of bone mineral density measurements demonstrate only less than 1% difference. The CZT detector appears to have many benefits for the application of bone densitometry. Its excellent energy resolution can enhance the counting accuracy of dual energy X-ray spectrum. Furthermore its compactness in physical dimension and no cooling requirement will be additional benefits for a more compact and accurate bone densitometer.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.651-655
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• 2011

We synthesized a novel cationic dendrimer consisting of a poly(amidoamine) dendrimer (PAMAM, generation 4) backbone with both L-arginine (Arg) at the termini and 6-aminohexanoic acid (Ahx) between the original core polymer and the peripheral Arg units. The sequential chemical modification of PAMAM G4 with Ahx and Arg resulted in higher transfection efficiency with much less cytotoxicity. PAMAM G4-Ahx-Arg formed stable polyplexes at weight ratios of 8:1 or higher (polymer: plasmid DNA), and the mean polyplex diameter was $180{\pm}20nm$. PAMAM G4-Ahx-Arg showed much higher transfection ability than PAMAM G4 or PAMAM G4-Ahx. Furthermore, PAMAM G4-Ahx-Arg was much less cytotoxic than PEI25KD and PAMAM G4-Arg. In addition to Arg grafting of the PAMAM dendrimer, which endows a higher transfection capability, the addition of Ahx spacer increased dendrimer hydrophobicity, introduced flexibility into the conjugated amino acids, and reduced cytotoxicity. Overall, it appears that the concomitant modification of PAMAM with Ahx and Arg could lead to new PAMAM conjugates with better performances.

• Archives of Plastic Surgery
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• v.44 no.5
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• pp.361-369
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• 2017

As the popularity of fat grafting research increases, animal models are being used as the source of pre-clinical experimental information for discovery and to enhance techniques. To date, animal models used in this research have not been compared to provide a standardized model. We analyzed publications from 1968-2015 to compare published accounts of animal models in fat grafting research. Data collected included: species used, graft characteristics (donor tissue, recipient area, amount injected, injection technique), time of sacrifice and quantification methods. Mice were most commonly used (56% of studies), with the "athymic nude" strain utilized most frequently (44%). Autologous fat was the most common source of grafted tissue (52%). Subcutaneous dorsum was the most common recipient site (51%). On average, $0.80{\pm}0.60mL$ of fat was grafted. A single bolus technique was used in 57% of studies. Fat volume assessment was typically completed at the end of the study, occurring at less than 1 week to one year. Graft volume was quantified by weight (63%), usually in conjunction with another analysis. The results demonstrate the current heterogeneity of animal models in this research. We propose that the research community reach a consensus to allow better comparison of techniques and results. One example is the model used in our laboratory and others; this model is described in detail. Eventually, larger animal models may better translate to the human condition but, given increased financial costs and animal facility capability, should be explored when data obtained from small animal studies is exhausted or inconclusive.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.700-705
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• 2006

Present studies were performed to determine the physiology of seed germination in Viola species native to Korea. Twelve species, 1 variety and 1 form were collected, classified and used as materials: V. collina, V. blandaefomis, V. rosii, V. chaerophylloides, V. phalacrocarpa, V. patrinii, V. mandshurica, V. mandshurica for. albescence, V. seoulensis, V. yedoensis, V. keiskei, V. variegata, V. variegata var. chinensis, and V. verecunda. V. tricolor 'Helen Mount' was also used to compare wild with cultivated species. In order to investigate the effect of temperature on seed germination, seeds stored at $4{\pm}2^{\circ}C$ for 10 months or 4 years were incubated at 10, 15, 20, $25^{\circ}C$ under 16h illumination with 4 replicates per treatment. Seeds which had not germinated at $10^{\circ}C$ were transferred to $30^{\circ}C$ to assess the effect of temperature change in germination. Germination percent and the days of first, 40% and 80% germination were assessed. Capability of seed germination varied with taxon; Species belonging to subsection Patellares had high ability of germination, compared to species in the other subsections, and series Chinensis was the best among subsection Patellares. Species capable of high germination germinated in all temperatures with reasonably high germination rate, but the other species responded sensitively to temperature with different germination patterns. Higher the temperature, shorter the incubation time required for first, 40% and 80% of germination. Therefore, high temperature was effective in almost all species, not only for inducing high rate of germination but also the uniformity of germination. Temperature change from $10^{\circ}C\;to\;30^{\circ}C$ had a positive effect on seed germination.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.4
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• pp.373-385
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• 2005

This study was carried out to investigate the lactation and weaning practice of infants and their mothers' attitude on infant nutrition. We interviewed 152 mothers in three pediatric clinics located in Sokcho city. From this survey, $76.3\%$ of infants was fed colostrum milk during first one week of life. During the first 4 months, $31.6\%$ of infants was fed breast-milk, while $42.8\%$ of them was fed bottled-milk. More housewives fed their babies with breast milk than the working mothers. Infants ate first weaning food at 5.73$\pm$1.86 months of life. Highly educated mothers showed positive response to the questionnaire : Breast-feeding is good for baby but it requires mother's sacrifice, and Breast-feeding may ruin the good shape of mothers. Highly income mothers responded negatively to the statement : Breast-feeding is not a must for infants since bottled-milk is a good substitution for breast-milk. Comparing with the mothers whose income was about 1 -2 million won per month, with ones who got paid less than 1 million won per month the former responded positively to : Breast-feeding is good for baby but it requires mother's sacrifice. Mothers recognized the importance of weaning in the following order : Supply of nutrition, Enforcement of digestion and absorption capability, Variety of taste, Disease prevention, Development of self-reliance, and Development of baby tooth. To improve the infants' nutritional status, education program on infant nutrition should be organized and run for the pregnant and lactating women in obstetrician and pediatric clinics and through the mass media as well.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.348-353
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• 2006

In this study, a 40% ethanol extract of Chinese yam flour (Dioscoreae rhizoma), containing $177{\pm}58{\mu}g/mL$ of dioscin, was tested in order to evaluate its pharmacological effects on the gastrointestinal tracts of Sprague-Dawley rats. Via the ingestion of the Chinese yam extract, the secretion of gastric acid was suppressed in the rats, and gastrointestinal motility increased by as much as 10%. The fecal quantity of rats fed on the Chinese yam extract also increased, by more than 40% as compared with that of the controls. The Chinese yam extract was found not to affect the growth of normal intestinal bacteria. However, a great deal of lactose-fermenting bacteria was observed in the fecal samples of rats fed for 6 weeks on 2% Chinese yam extract. This finding would appear to suggest that Chinese yam extract not only induces an improvement in digestive capability, but also affects the conversion of some intestinal flora to helpful bacteria. Our serochemical analyses indicated that serum glucose, neutral lipid, and total cholesterol levels were reduced to some degree by long-term feeding on Chinese yam extract. This finding bolsters the notion that Chinese yam extract may prove helpful as a digestion-aiding agent for patients suffering from hyperglycemia or hyperlipidemia.

• Nuclear Engineering and Technology
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• v.21 no.1
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• pp.1-11
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• 1989

Numerous losses of decay heat removal capability have occurred at U during stutodwn while its significance to safety is needless to say. A study is carried out as an attempt to assess what could be done to lower the frequency of these events and to mitigate their consequences in the unlikely event that one occurs. The shutdown risk model is developed and analyzed using Event/Fault Tree for the typical pressurized water reactor. The human cognitive reliability (HCR) model, two-stage bayesian approach and staircase function model are used to estimate human reliability, initiating event frequency and offsite power non-recovery probability given loss of offsite power, respectively. The results of this study indicate that the risk of a Pm at shutdown is not much lower than the risk when the plant is operating. By examining the dominant accident sequences obtained, several design deficiencies are identified and it is found that some proposed changes lead to significant reduction in core damage frequency due to loss of cooling events.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.39-46
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• 2008

The purpose of this study was to assess the cariogenic potential of infant confectionaries. In vitro, as compaired with 10% sucrose solution and whole bovine milk. Buffering capability were determined by amount of 0.1N lactic acid consumed to titrate the 50ml specimen solutions to pH 4.0. The pH of the specimen solution inoculated by streptococcus mutans was measured by pH meter and the surface microhardness tester, before and after 48 hours incubation. The buffering capacity of infant confectionaries was higher than that of sucrose solution and lower than that of milk, and there were significant difference between infant confectionaries(p<0.05). The pH of infant confectionaries after 48 hours incubation was similar to 10% sucrose solution, and there were significant difference between infant confectionaries and milk(p<0.05). The microhardness change of primary tooth enamel of infant confectionaries group after 48 hours incubation was similar to that of 10% sucrose solution, and there were significant difference between infant confectionaries and milk(p<0.05). In conclusion, infant confectionaries seemed to have the ability to cause dental caries in primary teeth, and there were significant differences of cariogenic potential among infant confectionaries. Cooperative efforts of dentistry and manufacturers to reduce the cariogenic potential of infant confectionaries would be necessary to prevent the early childhood caries in children.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.51-56
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• 2009

Purpose: Recently, most hospitals are introducing the PACS system and use of the system continues to expand. But small-scaled PACS called MicroPACS has already been in use through open source programs. The aim of this study is to prove utility of operating a MicroPACS, as a substitute back-up device for conventional storage media like CDs and DVDs, in addition to the full-PACS already in use. This study contains the way of setting up a MicroPACS with open source programs and assessment of its storage capability, stability, compatibility and performance of operations such as "retrieve", "query". Materials and Methods: 1. To start with, we searched open source software to correspond with the following standards to establish MicroPACS, (1) It must be available in Windows Operating System. (2) It must be free ware. (3) It must be compatible with PET/CT scanner. (4) It must be easy to use. (5) It must not be limited of storage capacity. (6) It must have DICOM supporting. 2. (1) To evaluate availability of data storage, we compared the time spent to back up data in the open source software with the optical discs (CDs and DVD-RAMs), and we also compared the time needed to retrieve data with the system and with optical discs respectively. (2) To estimate work efficiency, we measured the time spent to find data in CDs, DVD-RAMs and MicroPACS. 7 technologists participated in this study. 3. In order to evaluate stability of the software, we examined whether there is a data loss during the system is maintained for a year. Comparison object; How many errors occurred in randomly selected data of 500 CDs. Result: 1. We chose the Conquest DICOM Server among 11 open source software used MySQL as a database management system. 2. (1) Comparison of back up and retrieval time (min) showed the result of the following: DVD-RAM (5.13,2.26)/Conquest DICOM Server (1.49,1.19) by GE DSTE (p<0.001), CD (6.12,3.61)/Conquest (0.82,2.23) by GE DLS (p<0.001), CD (5.88,3.25)/Conquest (1.05,2.06) by SIEMENS. (2) The wasted time (sec) to find some data is as follows: CD ($156{\pm}46$), DVD-RAM ($115{\pm}21$) and Conquest DICOM Server ($13{\pm}6$). 3. There was no data loss (0%) for a year and it was stored 12741 PET/CT studies in 1.81 TB memory. In case of CDs, On the other hand, 14 errors among 500 CDs (2.8%) is generated. Conclusions: We found that MicroPACS could be set up with the open source software and its performance was excellent. The system built with open source proved more efficient and more robust than back-up process using CDs or DVD-RAMs. We believe that the operation of the MicroPACS would be effective data storage device as long as its operators develop and systematize it.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.548-556
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• 2021

This study was conducted to investigate the applicability of lignocellulosic fiber and coconut shell activated carbon (CSA) for the production of a particulate matter (PM)-reducing air-filter as raw materials to solve the environmental problems of non-woven fabrics. CSA had a good potential to use as a raw material of air-filter for reducing volatile organic compounds as well as noxious metals, and reduction capability of the CSA was 5 times higher than that of wood fiber. Natural adhesives formulated with proteinaceous wastes mostly were applied successfully to fabricate air-filters with the shape of fiberboard. The air-filter fabricated with the minimum target density of 200 kg/m³ and the maximum CSA-content of 40 wt% in fiberboard had a good manageable strength. However, the fiberboard filters was required to make vent-holes for improving an air-permeability of the filters. Size of the CSA particles was adjusted to greater than 2 mesh with the consideration of strength and formability of the fiberboard. Three-layers fiberboard that only wood fiber and the mixture of wood fiber and CSA were formed in the surface and middle layers, respectively, was determined to the optimal condition for the production of air-filters. In addition, traditional Korean paper handmade from mulberry trees (TKP) showed a good PM-reducing property as an air-filter. It is concluded that air-filtering set composed of fiberboard with vent-holes and TKP instead of conventional air-filters made with non-woven fabrics can be used as a filter for reducing the concentrations of PM, VOC and noxious metals existed in indoor and outdoor spaces.