KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.

It has been investigated on the management of Strontium-90 in KAERI. It is needed to separate the solute from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt in our previous study. Strontium chloride was successfully carbonated by reactive distillation of SrCl2 – K2CO3 – LiCl – KCl system. In this study, it was tried to develop another route to recover strontium from the salt solution by a solid-solid reaction for avoiding the entrainment of product and the salt-K2CO3 reaction. Reactive distillation experiments were carried out for SrCl2 - K2CO3 – LiCl – KCl system. The carbonation temperature and pressure were 520°C and 0.8 bar. After the carbonation reaction, the temperature was elevated to 820°C to remove KCl from the reaction product. SrCO3 and KCl peaks were found in the XRD analysis of the residual product. It could be concluded that SrCl2 can be successfully carbonated after salt removal by the solid-solid reaction.

It has been investigated on the management of the nuclides in KAERI. Strontium-90 is a high heatgenerating nuclide in spent nuclear fuel. It is needed to separate the salt from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt. It was investigated on operating conditions of reactive distillation process for the recovery of the strontium from the salt solution. At a reduced pressure, considerable amount of the carbonation agents such as K2CO3 and Li2CO3 were reduced during heating in the distiller due to the thermal decomposition. Therefore, the two step process was proposed, which is composed of a reaction step at an atmospheric pressure and a salt distillation step at a reduced pressure. In the reaction step, the condition of low temperature and high pressure is suitable to suppress the decomposition of the carbonation agent. In the salt distillation step, reduced pressure is preferable at a suitable temperature depending on the evaporation rate of the salt.

PURPOSES : The objective of this study is to determine the characteristics of nitrogen oxide (NOx) concentration in an exclusive median bus lane station. The hourly variations of NOx concentration and the effect of traffic volume on NOx concentration were analyzed using NOx measurement data and the number of vehicles at the station. METHODS : Data were collected using the chemiluminescence method for NOx concentration. Atmospheric information and traffic volume of buses were collected from the Korea Meteorological Administration and Bus Information System, respectively. RESULTS : As a result, the NO2 concentration in the test section was found to have a strong correlation with those in the atmospheric measurement station located near the test-bed. In addition, the average NOx concentrations in the test section were significantly higher than those of the other monitoring stations due to bus emissions. The average NOx concentration in the exit section was higher than that in the entry section owing to the vehicle’s frequent stops and fuel consumption due to acceleration. During the measurement period, the average NOx concentration was measured as approximately 33 % higher in the exit section than in the entry section. In addition, the NOx concentration at the bus station was found to increase as the bus dwell time increased, rather than the number of bus passages. CONCLUSIONS : This study provides clear characteristics of the NOx correlations with traffic information in an exclusive median bus lane station. It was shown that the NOx concentration at the bus station increased as the number of passes and bus dwell time increased. According to the coefficient of determination, the dwell time is more closely correlated to the NOx concentration at the bus station than the number of bus passes, indicating that it is a better parameter for predicting NOx concentration at bus stations.

Fibrous adsorbents, such as activated carbon fibers (ACF) have acknowledged advantages of rapid adsorption rate and ease of modification compared with granular and powdered adsorbents. Based on the surface modification of lyocell-based ACF, we observed different surface characteristics of ACF samples with variation in the mixing ratio and impregnation time of H3PO4, NaCl, and KMnO4 solution. For an engineering application, we also explored the adsorption characteristics of thusproduced ACF samples onto volatile organic compounds (VOCs). Isothermal adsorption experiments were performed using toluene and benzene as adsorbates. Results indicate that both physical and chemical surface properties have an effect on the adsorption of volatile organic compounds (VOCs).

A study on indigenous diatoms was carried out at 10 sites from May 2014 to December 2016 in marine and freshwater in Korea. Seventeen species of diatoms are new to Korea and they are divided into 3 classes, 4 subclasses, 10 orders, 14 families, and 16 genera. The nomenclatures, references, dimensions, specimens examined, local habitat, distribution in Korea, and photograph are reported here. Seventeen species found in marine, freshwater, and brackish water showed species-specific habitats.

Aneurysmal bone cyst (ABC) in maxilla is a rare and benign lesion but shows extensive bony destruction, occasionally accompanied with secondary osseous lesions, i.e., central giant cell granuloma, ossifying fibroma, fibrous dysplasia, etc. As the pathogenesis of ABC has not been clearly defined, ABC is diagnostically challenged due to its variable histological features. A 17-year-old boy showed a huge radiolucent lesion at right anterior maxilla, which was accidentally found in routine dental-radiological examination for orthodontic treatment. He had no medical history of systemic disease, and did not remember any traumatic experience on his right anterior maxilla. The radiolucent lesion involved periapical area from right central incisor to right first premolar, and was clinically diagnosed as odontogenic keratocyst. During surgical operation a cyst-like sac was enucleated with severe hemorrhage. In the histological observation the thick fibrous sac showed no lining epithelium, and its luminal side disclosed multiple aneurysmal spaces which were shrunken and almost obliterated. The fibrous sac itself was hyperplastic with abundant vascular channels, and produced fibromatous thickening associated with ossifying trabecular bones. This fibro-osseous tissue was hamartomatous, which was not directly connected and organized with marrow bone of maxilla. Finally, the present case was diagnosed as secondary type ABC differentially from traumatic bone cyst (TBC), odontogenic cyst, and central reparative granuloma. And it was presumed that the hamartomatous proliferation of fibro-osseous tissue in the cystic sac of ABC could produce the swelling pressure effect in the bone marrow similar to the overgrowth of central giant cell granuloma, ossifying fibroma, fibrous dysplasia, etc., in the secondary type ABC.

Caliber persistent artery (CPA) is a vascular anomaly presenting as a bluish and pulsatile artery in the subepithelial tissue. Although the incidence of CPA was debated, many CPAs occurred in the perioral and facial tissues at which the embryonal strapedial artery networks were distributed. The present study demonstrated a case of CPA occurred in the retromolar buccal mucosa in a 37 years old male. The lesion showed many pinkish granular spots, but was asymptomatic except biting irritation during mastication. It had slowly increased in size up to 20 × 25 mm for 3 years, and recently became hemorrhagic due to the biting injury between left upper and lower second molars. With the fear of oral cancer an incisional biopsy was performed, and followed by histological and immunohistochemical study. Histologically the lesion showed many tortuous artery localized at the submucosa area, and the arterial wall was thick and its lumen was narrowed and shrunken. In the immunochemistry α-SMA was positive for thick smooth muscle layer of artery and arterioles, TGase 2 was weakly positive for the luminal surface of arterial intima, and bFGF was consistently positive for the perivascular fibrous tissue. But PCNA, VEGF, CD31, CMG2, TGF-β1, HSP-70, and 14-3-3 were almost negative for the vascular tissue. Therefore, it was presumed that the lesion was not actively proliferative nor degenerative but still retained its cellular stability and slow growing potential. It was finally diagnosed as CPA differentially from arterio-venous malformation, hemangioma, lymphangioma, and squamous cell carcinoma. The retromolar buccal mucosa CPA is first reported in this study and may present usual clinical findings depending on its size and location. This asymptomatic lesion could be severely hemorrhagic by minor biting injury, therefore, precise differential diagnosis should be made through biopsy, and careful therapy be followed.

A 57 years old female received xenogenic bone graft for the extraction socket augmentation of right maxillary molars and for the sinus floor elevation six months ago. The bone graft sites were healed uneventfully and showed marked radiopacity in the postoperative X-ray view. Before dental implant insertion the bone biopsy was made using trephine bur and examined pathologically. The graft bones showed minimum new bone deposition with dysplastic epithelium. The epithelium was proliferative on the surface of graft bones forming epithelial strands and nests, similar to the odontogenic epithelium. The immunohistochemical study was performed using different antisera of odontogenic markers, growth factors, oncogenes, etc. The epithelial cells were strongly positive for pan-keratins, EGF, pAKT, and HSP-70, consistently positive for PCNA, p53, EGFR, 14-3-3, and survivin, slightly positive for ameloblastin, but rarely positive for amelogenin. Particularly the matrix of graft bone was slightly positive for EGF. Taken together, it is presumed that the abnormal epithelium on the graft bones was derived from odontogenic epithelial elements, Malassez epithelial rests, distributed at the periodontal tissue of maxillary molars, and that they might undergo dysplastic proliferation affected by the release of growth factors and osteogenic proteins from the graft bones. It is also suggested that the graft bone substitutes inserted for the dental implant possibly have a potential to induce the proliferation of odontogenic epithelial rests leading to the pathogenesis of odontogenic cysts and tumors.

A study on the indigenous diatoms was carried out at 103 sites during August 2008 to April 2011 from the marine and the brackish waters in Korea. A fine structure of small-sized diatoms was examined using a light and scanning electron microscopy. Sixty species of diatoms were newly identified and composed of 3 class, 6 subclass, 16 order, 21 family and 39 genus. The detailed nomenclatures, references, photographs and distributions were here reported. Of 60 species, the most frequent species was Tryblionella coarctata appearing 24 times, and 22 times followed by Thalassiosira lacustris, Cocconeis stauroneiformis was 20 times. In the level of genus, Chaetoceros, Parlibells and Thalassiosira were included 4 species, Actinocyclus, Minidiscus and Licmophora were included 3 species. This study will provide the knowledge of the diversity level of diatom in Korea, the knowledge is important on the diatoms for further studies.

The purpose of this study was to determine the effects of heat appli˗ cation on the immune activities of the human body. To exam, further˗ more, the immune effect from the healthy volunteer(male:15, female:15) by monitoring changes of immune substances such as various leukocytes[total white blood cell(WBC), eosinophil, neutrophil, basophil, monocyte, and lymphocyte], a comparative study with warm water immersion(40.8±0.3℃) and infrared(250W) was carried out. The plasma analysis showed that the count of white blood cell, eosinophil, and neutrophil were elevated in warm water immersion- or infrared˗ stimulated group compared with control group. However, the count of basophil was decreased in both warm water immersion- and infrared-stimulated group than control group. Therefore, these results suggest that the thermostimulation improved immune activity.

Trunk injection of nematicides is applied to prevent pine wilt disease(PWD). Although the trunk injection of nematicides is effective to PWD prevention, it is not effective to vector insects such as adults of M. alternatus and M. saltuarius. Thus, This study was investigated for the insecticidal activity and the effect of feeding deterrence by injecting to pine trees with acetamiprid. For screening effective nematicides, some insecticides were injected to pines on December 30th, 2008 and their insecticidal activities and feeding areas of M. alternatus and M. saltuarius were investigated in the insects breeding dishes (100× 40mm) where put on 1 to 2-year-old twig which was selected from injected pine trees in early June. As a result, insecticidal activity and feeding deterrence of acetamicprid were most effective. Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, were 170.3±107.0 mm2 and 258.0±123.2 mm2 respectively. And Feeding areas of M. alterantus adults, when tested with 1-year-old twig and 2-year-old twig of pines injected at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid, were 57.7±72.3 mm2 and 65.7±51.2 mm2 respectively and their mortalities also were 0%, 28.6%. The feeding areas of M. alterantus adults tested with 1-year-old twig and 2-year-old twig of pine trees injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it and the mortalities were 28.0%, 57.1% respectively. In case of the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of healthy pine trees, it was 112.±35.1 mm2 and 159.2±65.2 mm2 respectively. And the feeding areas of M. saltuarius adults, when tested with 1-year-old twig and 2-year-old twig of injected pine trees at a dose of 0.3 ml per cm dbh of a pine tree with acetamiprid were 0.61±0.0 mm2 and 8.1±12.4 mm2 and both mortalities were 23.1%. Although M. saltuarius adults, when tested with 1-year-old twig of a pine tree injected at a dose of 0.6 ml per cm dbh of a pine tree with acetamiprid, were not fed on it but M. saltuarius adults tested with 2-year-old twig of the same pine tree were 2.0±3.7 mm2 and their mortalities were 53.8%, 61.5% respectively. We investigated insecticidal activities, the effects of feeding deterrence of acetamiprid for vector insects where fed twigs of injected pines by stop up hole with a cork or not, and the trunk injection to pine trees at a dose of 0.5, 1 ㎖ per ㎝ dbh of a pine tree with acetamiprid on the early June. As a result, all of the vector insects were not fed and the feeding area was within 11 ㎟ and the mortality of M. alternatus was 70%.