• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.145-155
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• 2002

The results of the present feasibility study are summarized as follows, 1. The three unit bridge of knitted material and UD fibre reinforcement has both the rigidity and the strength against a vertical occlusal load of 75N. 2. Stress concentration at the junctional area between the bridge and the abutments, i.e. between the pontic and the knitted caps was observed. In the case of the bridge with reinforcement straps, it was partly shown that the concentration problem could be improved by simply increasing the fillet size at the area. Further refining in the surface of the junctional area will be needed to ensure a further improvement in the stress distribution. This will require some trade off in the level of the stress and the available space. A parametric study will help to decide the appropriate size of the fillet. 3. Design refinement is a must to improve the stress distribution and realize the most favourable shape in terms of fabrication. The current straight bar with a constant cross section area can be redesigned to a tapered shape. The curve from the dental arch should also be placed on the pontic design. In accordance with design refinement, the resistance of the bridge frame to other load cases should be evaluated. 4. Although not included in the present feasibility study, it is estimated that bridges of the anterior teeth can be made strong enough with the knitted material without further reinforcement using unidirectional materials. In this regard, a feasibility study on design concepts and stress analysis for 3, 4, 5 unit bridge is suggested. 5. Two types of bridge were analysed in terms of fatigue. The safe life design concept, i.e. fatigue design concept, looks reasonable for the bridge where if cracks should form and propagate there is virtually nothing a dentist to do. The bridge must be designed so that no crack will be initiated during the life span. In the case of crowns, however, if constructed with composite resin with knitted materials, it might be possible to repair them, which in general is impossible for crowns of PFM or of metal. Therefore for composite resin crowns, a damage tolerance design concept can be applied and reasonably higher operational stresses can be allowed. In this case, of course, a periodic inspection program should be established in parallel. 6. Parts of future works in terms of structural viewpoint which need to be addressed are summarized as the following: 1) To develop processing technology to accommodate design concepts; 2) More realistic modelling of the bridge and analysis-geometry and loading condition. Thickness variation in the knitted material, taper in the pontic, design for anterior tooth bridge, the effect of combined loads, etc, will need to be included; 3) To develop appropriate design concepts and design goals for the fibre composite FPD aiming at taking the best advantage of knitted materials, including the damage tolerance design concept; 4) To develop testing method and perform test such as static ultimate load test, fatigue test, repair test, etc, as necessary.

• Journal of Life Science
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• v.22 no.6
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• pp.703-712
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• 2012

Adeno-associated virus (AAV) has been considered to be a very safe and efficient gene delivery system. However, the major obstacles to therapeutic usage of AAV have been to achieve highly efficient and reproducible production processes, and also to develop a reliable quantifying method of various serotypes with a simple protocol. We compared the efficiency of the conventional production protocol of AAV2 and adenovirus (Ad) co-infection to that of a new method containing AAV2 infection followed by pHelper transfection. We tested HEK293 and 293T, and further examined the time-dependent changes of AAV2 production. The new method of AAV2 and pHelper DNA gave about ten times higher production efficiency than that of the conventional protocol. The highest production efficiency in 293T was achieved as $1.61{\times}10^5$ virus genomes (v.g.)/cell by the new method of 10 MOI of AAV2 infection and 5 days post-infection. This protocol of the highest efficiency was then applied to produce various AAV serotypes and showed the efficiencies higher than $10^5$ v.g./cell. Next, we designed the universal PCR primers of highly conserved regions for various AAV serotypes to develop a simple and reliable titration method. The universal primers could amplify all the tested AAV serotypes with similar sensitivities by ten molecular copies. Therefore, this pair of universal primers can be further utilized to detect AAV contaminants in therapeutic adenoviral vectors.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.15-21
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• 2006

In order to monitor the pesticide residues in/on peppers and pepper powder and to assess their risk, pesticides in/on green pepper from 10 farmgates and fresh red pepper from 9 farmgates in Chungbuk area and pepper powder from 6 wholesale markets in Cheongju city were analyzed with a GLC and an HPLC. Also, pepper powder made by pulverization of the dried red pepper was analyzed to elucidate the change of pesticide residues in fresh red pepper by oven-drying. The number of pesticides detected from peen pepper, fresh red pepper, dried red pepper and pepper powder were 9, 12, 12, and 17, respectively, including 10 pesticides (one fungicide and nine insecticides) which were exceeded the maximum residue limits (MRLs). The exceeding rate of the MRL were higher in dried red pepper and pepper powder than in green pepper and fresh red pepper. Although some pesticides in peppers and pepper powder exceeded the MRLs, their estimated daily intake(EDI) were less than 1.6% of their acceptable daily intakes(ADIs), suggesting that it would be estimated to safe. By oven-drying of fresh red pepper at $65^{\circ}C$ for 72 hours, the weight of dried red pepper was from 1/5.9 from 1/7.8 of fresh red pepper, while the concentration of pesticide residue in dried red pepper increased from 1.7 to 8.2 times, suggesting that further reconsideration was required for the MRL of pepper powder.

• Tuberculosis and Respiratory Diseases
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• v.39 no.1
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• pp.35-41
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• 1992

Background: Massive hemoptysis is a major clinical and surgical problem related to high motality. Bronchial and nonbronchial systemic arteries are considered to be the main source of hemoptysis. Embolization of these arteries has become an accepted treatment in the management of massive hemoptysis. Herein we evaluate the effect of arterial embolization in immediate control of massive hemoptysis and investigate the clinical and angiographic characteristics and the course of patients with recurrent hemoptysis after initial successful embolization. Method: 21 patients (15 men & women, aged 21 to 74 years) underwent transcatheter arterial embolization for the treatment of life-threatening massive hemoptysis from Jan 1988 to July 1991. Seven patients had inactive residual pulmonary tuberculosis, 5 cases aspergilloma, 4 cases active pulmonary tuberculosis, 3 cases bronchiectasis and 2 case lung cancer. Arteriography was done by percutaneous catheterization via the femoral artery, and at the same time, arterial embolization was done with gelfoam particle. Result: Immediate control of massive hemoptysis was achieved in all 21 cases by arterial embolization. Hemoptysis recurred in nine of 21 patients. Four cases were aspergilloma, two inactive tuberculosis, two lung cancer, and one bronchiectasis. The initial angiographic findings revealed that nonbronchial systemic arterial supply, bronchial-pulmonary arterial shunt, and marked vascularity were more frequently, but statistically insignificant, in recurred patients. The following complications occured: fever, chest pain, cough, voiding difficulty, paralytic ileus, paraplegia, and splenic infarction. The course of the recurred patients was as follows: Three patients were died due to recurred massive hemoptysis. one was aspergilloma and two lung cancer. Surgical resection could be performed successfully in two patient with relatively good lung function, one aspergilloma and the other inactive tuberculosis. In 4 patients with poor lung function, repeated embolization or medical conservative treatment was continued. Conclusion: Arterial embolization as initial treatment of massive hemoptysis is most useful and relatively safe, although this is a palliative procedure and the potentiality for recurrence exists. Repeated embolization in inoperable patient with recurrent bleeding may improve the lengthening of life.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.52-58
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• 2004

This work was conducted to provide the reference data of radioactivity in the foodstuffs at a radiological emergency situation in Jeju Island The sampled foodstuffs were agricultural (31), livestock (6), marine (12) and forest products (4), and processed foods (3) consumed by Jeju Islanders. $^{137}Cs$ and $^{40}K$ activities were determined by HPGe r-ray spectromety. The activity ranges of $^{137}Cs$ was ${\sim}650\;mBq/kg$ fresh in the agricultural products, ${\sim}131\;mBq/kg$. fresh in the livestock, ${\sim}834\;mBq/kg$ fresh in the forest, ${\sim}253\;mBq/kg$ fresh in the marine and $32.0{\sim}483\;mBq/kg$. fresh in the processed foods (tea). In case of $^{40}K$ the activity was $16.6{\sim}542\;Bq/kg$. fresh in the agricultural products, $39.1{\sim}294\;Bq/kg$ fresh in the livestock, $85.5{\sim}116\;Bq/kg$ fresh in the forest, $50.1{\sim}657\;Bq/kg$ fresh in the marine, and $33.6{\sim}1,065\;Bq/kg$ fresh in the processed foods (tea). The highest activity of $^{137}Cs$, 834mBq/kg fresh was observed in oak mushroom and $^{40}K$ 1,065 Bq/kg fresh in coffee. Annual effective doses of $^{137}Cs$ and $^{40}K$ by intake of foodstuffs per capita were the following order; agricultural products (66,543 nSv) > livestock products (19,311 nSv) > processed foods (6,648 nSv) > marine products (6,579 nSv) > forest products (860 nSv). Therefore, total annual effective dose was summed 99,941 nSv which is quite low level comparing to the annual effective dose by external exposure, 2,400,000 nSv. The data obtained in this study can be useful for monitoring whether the foodstuffs are contaminated or not at an emergency radiation accident, and showed that the foodstuffs consumed in Jeju are safe in terms of annual effective dose of $^{137}Cs$ and $^{40}K$

• Journal of Life Science
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• v.26 no.12
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• pp.1376-1382
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• 2016

Xylitol is widely used in the food and medical industry. It is produced by the reduction of xylose (lignocellulosic biomass) in the Saccharomyces cerevisiae strain, which is considered genetically safe. In this study, the expression system of the GRE3 (YHR104W) gene that encodes xylose reductase was constructed to efficiently produce xylitol in the S. cerevisiae strain, and the secretory production of xylose reductase was investigated. To select a suitable promoter for the expression of the GRE3 gene, pGMF-GRE3 and pAMF-GRE3 plasmid with GAL10 promoter and ADH1 promoter, respectively, were constructed. The mating factor ${\alpha}$ ($MF{\alpha}$) signal sequence was also connected to each promoter for secretory production. Each plasmid was transformed into S. cerevisiae $SEY2102{\Delta}trp1$, and $SEY2102{\Delta}trp1$/pGMF- GRE3 and $SEY2102{\Delta}trp1$/pAMF-GRE3 transformants were selected. In the $SEY2102{\Delta}trp1$/pGMF-GRE3 strain, the total activity of xylose reductase reached 0.34 unit/mg-protein when NADPH was used as a cofactor; this activity was 1.5 fold higher than that in $SEY2102{\Delta}trp1$/pAMF-GRE3 with ADH1 as the promoter. The secretion efficiency was 91% in both strains, indicating that most of the recombinant xylose reductase was efficiently secreted in the extracellular fraction. In a baffled flask culture of the $SEY2102{\Delta}trp1$/pGMF-GRE3 strain, 12.1 g/l of xylitol was produced from 20 g/l of xylose, and ~83% of the consumed xylose was reduced to xylitol.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• Journal of Dairy Science and Biotechnology
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• v.26 no.2
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• pp.23-30
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• 2008

This study implicated that the CBT-AK5 purified from Lactobacillus casei (LAFTI L26) which showed antitumor activity in ICR mice. Hence, ICR mice were inoculated intraperitoneally Sarcoma-180 as well as CBT-AK5. Then we observed the life span and tumor increment of those ICR mice. Here our studies showed effect on two different way of treatment as intraperitoneally and orally treated in Sarcoma-180 infected ICR mice. We found that intraperitoneally treatment of Sarcoma-180 and CBT-AK5 is more effective than orally fed. The life span of the ICR mice were highly reduced after the inoculation of Sarcoma-180. Those effects like increment of body weight, the growth of ascites and solid were inhibited significantly after the treatment of CBT-AK5 in Sarcoma-180 infected ICR mice. Finally these studies suggested that CBT-AK5 isolated form Lactobacillus casei showed excellent antitumor activity against Sarcoma-180 infected ICR mice.

• Journal of Life Science
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• v.28 no.5
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• pp.524-531
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• 2018

The essential oil from Abies koreana E.H. Wilson had been developed, however, its efficacy has not yet been studied especially in terms of skin care research. The aim of this study is to investigate the effects of Abies koreana extracts (AKE) on melanogenesis and wrinkle formation in B16F10 melanoma cells (B16F10) and human dermal fibroblast cell line (HDF). The essential oil was extracted by hydrodistillation method and purified by anhydrous sodium sulfate. At a concentration of $10^{-5}$-fold, viability in these cells had been defined by cytotoxicity assays. Anti-melanogenic effects on B16F10 were evaluated using tyrosinase inhibition assay, and real-time PCR for verifying gene expression of tyrosinase, tyrosinase related protein-1 and -2 (TRP-1 and -2). AKEs reduced about 5-fold of tyrosinase inhibitory activity compared to ${\alpha}$-melanocyte-stimulating hormone (${\alpha}$-MSH)-induced group and about 30% reduction compared to Arbutin induced group. The mRNA levels of three melanin-related factors were increased, separately. To investigate the effects of anti-wrinkle, procollagen type I c peptide synthesis assay (PIP) and Western blot were performed. At AKE-treated group, PIP was up-regulated and the expression of collagen type 1 and matrix metalloproteinase (MMP)-1 were improved. Furthermore, AKE presented anti-wrinkle effects by increasing UVB-inhibited collagen type 1 expression, and reducing UVB-induced MMP-1 production at $60mJ/cm^2$ of UVB radiation. Therefore, Abies koreana extracts has potentials as a safe and an effective skin ingredient for whitening and anti-wrinkle.

• Journal of Life Science
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• v.28 no.5
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• pp.605-614
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• 2018

Bee pollen has an outer wall which is resistant to both acidic and basic solutions and even the digestive enzymes in the gastrointestinal tract. Therefore, the oral bioavailability of bee pollen is only 10-15%. A previous study reported on wet-grinding technology which increased the extraction of active ingredients from bee pollen by 11 times. This study was designed to investigate the safety of wet-ground bee pollen. First, a single dose of wet-ground bee pollen was tested in both rats and beagle dogs at dosages of 5, 10, and 20 g/kg and 1.5, 3, and 6 g/kg, respectively. In rats, compound-colored stools were found in those administered 10 g/kg or more of wet-ground bee pollen. In beagle dogs, 6 g/kg of wet-ground bee pollen induced diarrhea in one male for four hours. However, no obvious clinical signs were found through the end of the experiment in rats and beagle dogs. In addition, no histological abnormality was found in all animals. The data indicates that a single dose of up to 20 g/kg of wet-ground bee pollen is safe. Next, the genetic toxicity of nano-sized bee pollen was tested. This study employed a bacterial reverse mutation test, a micronucleus assay, and a chromosomal aberration assay. In the micronucleus assay, there was no genetic toxicity up to the dosage of 2 g/kg. There was also no genetic toxicity in the bacterial reverse mutation test and chromosomal aberration assay. This data provides important information in developing nano-sized bee pollen into more advanced functional foods and herbal medicines.