• Research in Plant Disease
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• v.22 no.4
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• pp.227-235
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• 2016

Plant disease caused by root-knot nematode is a major problem in crop production. Using of chemical pesticides, one of the most efficient methods to control nematodes, have raised issues in toxicity to humans and animals and environmental pollution. In this study, to select actinomycete strains that have potential to serve as a microbial agent for control of nematodes, we investigated nematicidal activity of culture broth from 670 Streptomyces isolates. A culture filtrate of KRA15-528 isolate that was identified as S. flavogriseus on the basis of 16S rRNA sequence analysis, showed strong nematicidal activity against second stage of juveniles of Meloidogyne incognita and inhibited egg hatching; exposure to 10% of culture filtrate resulted in 71% juvenile mortality at 48 hours afters treatment and suppressed egg hatching by 54% at 9 days after treatment. When the KRA15-528 culture filtrate was partitioned with ethyl acetate and butanol, ethyl acetate layer exclusively showed strong activity; 91%, 53%, 30% of mortality at 1,000, 500, $250{\mu}g/ml$, respectively. Additionally, the culture filtrate suppressed gall formation on cucumber plant by M. incognita with no phytotoxicity. These results suggest that S. flavogriseus KRA15-528 has potential to serve as a microbial nematicide for the control of root-knot nematode disease.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.1
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• pp.20-26
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• 2013

Purpose: The purpose of this study was to evaluate the bond strengths between the latest CAD/CAM ceramic inlay and various resin cements which are used primarily for esthetic restoration. Materials and methods: Cylindrical ceramic blocks(Height: 5 mm, diameter: 3 mm) were fabricated by using Cerec3 and bonded on the dentin of the ninety extracted caries-free molars using three different kinds of resin cement(Unicem$^{(R)}$, Biscem$^{(R)}$, and Variolink II$^{(R)}$) according to the manufacturer's instructions. Ninety specimens were divided into 3 groups according to three different kinds of resin cement. Half of each group were conducted thermocycling under the conditions of the $5-55^{\circ}C$, 5,000 cycle but the other half of them weren't. All specimens were kept in normal saline $37^{\circ}C$, for 24 hours before measuring the bond strength. The shear bond strength was measured by Universal testing machine with a cross head speed of 0.5 mm/min. The results were analyzed statistically by t-test and one-way ANOVA. Results: Unicem$^{(R)}$ group showed the highest shear bond strength despite a slight decline by thermocycling. The shear bond strength of Unicem$^{(R)}$ group and ValiolinkII$^{(R)}$ group were significantly influenced by thermocycling, whereas Biscem$^{(R)}$ group was not influenced (P<.05). There were no significant differences in the bond strength between the three groups without thermocycling, but there was significant differences between Unicem$^{(R)}$ group and Valiolink II$^{(R)}$ group with thermocycling(P<.05). Conclusion: It has been shown to be clinically effective when the self-adhesive resin cements Unicem$^{(R)}$ and Biscem$^{(R)}$ were used instead of the etch-and-rinse resin cement Valiolink II$^{(R)}$ during the bonding of CAD/CAM ceramic inlay restorations with teeth.

• Journal of Life Science
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• v.28 no.5
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• pp.517-523
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• 2018

Elevated levels of cortisol caused by chronic stress may lead to neuron damage in the hippocampus by activating the glucocorticoid receptors (GRs). In cortisol-deficient animals, corticosterone is known to function as a stress hormone. In humans however, corticosterone is considered a precursor of aldosterone and a glucocorticoid with similar properties to cortisol. Recently, many studies have been conducted on the role of cortisol and other synthetic glucocorticoids like dexamethasone in humans, but the exact function of corticosterone is unknown. This study examined the viability of human neuroblastoma SH-SY5Y cells treated with various concentrations of corticosterone for 24 and 48 hr via MTT assay. The MTT-assay results showed that corticosterone had an antiproliferation effect on SH-SY5Y cells at higher concentrations (500 and $1,000{\mu}M$), while in lower concentrations ($100{\mu}M$), it showed no antiproliferation effect. Cytotoxicity analysis of extracts from three medicinal crops (Liriope muscari, Schisandra chinensis, and Wolfiporia extensa) revealed that they all possessed deleterious effects on SH-SY5Y cells depending on dosage. However, it was observed that, at a concentration of $500{\mu}g/ml$, Liriope muscari attenuated the corticosterone-induced antiproliferation on SY-SH5Y cells and restored cell growth after 48 hours of treatment. The study examined the synergistic effect of six mixtures each containing $500{\mu}g/ml$ of Liriope and various concentrations of Schisandra (50 or $100{\mu}g/ml$) and Wolfiporia (10, 30, and $50{\mu}g/ml$). The results showed minor growth-restoration activity but less than that of Liriope muscari only, suggesting that Schisandra and Wolfiporia had no additive or synergistic effects.

• Tuberculosis and Respiratory Diseases
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• v.43 no.5
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• pp.683-692
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• 1996

Background: Although most of the patients with tuberculous pleural effusions completely reabsorbed their effusions and became asymptomatic within 2 to 4 months, later surgical procedures such as decortication is needed in some patients because of dyspnea caused by pleural loculations and thickening despite anti-tuberculous chemotherapy. It is obligatory to secure adequate drainage to prevent the development of complications. But, the best methods for treating loculated tuberculous pleural effusions remain debatable. Recent several reports revealed that intrapleural instillation of fibrinolytic agents is an effective adjunct in the management of complicated empyema and may reduce the need of surgery. Purpose : The effects of catheterization with intrapleural urokinase instillation were prospectively evaluated in the patients with septated tuberculous pleural effusion, and compared with other therapeutic effects of different modalities of therapy such as repeated thoracentesis and small-bored catheterization. Methods : Forty-eight patients diagnosed with tuberculous pleurisy were randomly separated into three groups; control group(n=13), catheter group(n=12), urokinase group(n=22). In urokinase group, dose of 100.000U urokinase was instilled into the pleural cavity via a percutaneous drainage catheter for complete drainage or total dose of 700,000U of urokinase. After two hours clamping, the catheter was opened and intermittently irrigated. The early and late effectiveness of therapies was assessed by radiographically and by measuring the volume of fluid drained from the catheter. Results : There was statistically significantly better result in the urokinase group in respect of frequency of catheterization, frequency of catheter obstruction and the duration of catheterization in early effectiveness(p < 0.05). There were no difference in radiologic improvement of follow-up in later phase chest X-ray between urokinase group and catheter group in later phase(p > 0.05). But there were more failure rates in control group especially honeycomb septa in pleural effusion sonographically than former two groups. And there were no complications of urokinase such as fever or hemorrhage. Conclusion : In the treatment of septated tuberculous pleurisy, there were better results in urokinase than those of catheterization alone in early effectiveness. And there was no difference in radiographic improvement between urokinase group and catheter group. Intrapleural instillation of urokinase is an effective and safe mode of treatment for septated tuberculous pleural effusions and alleviates the need for thoracotomy.

• Journal of Korean Academy of Nursing
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• v.5 no.2
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• pp.11-22
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• 1975

Suicides have been considered to be one of the grave problems of modern societies. According to recent police statistics of Republic of Korea, 28.6 suicides in every 100, 000 were reported. Psychiatric Patients are believed to be predisposed to suicidal tendencies. This study was performed to investigate the characteristics of suicidal attempts and to analyse the environmental factors involved in the suicidal accidents of patients admitted to psychiatric hospitals. Records of 66 suicidal accidents from three psychiatric hospitals during the period of January 1971 through June 1971 were sampled. Data were analysed by percentile score. Results are as follows; 1. The age group of 21~30yrs. was revealed to be the highest in frequency of suicidal attempts (50.0%) Among the unsuccessful suicides; the age group of 31~40yrs. in men and the age group of 21~30 yrs. in women revealed to be the highest in frequency-Among the unsuccessful suicides; the age group of 21-30 yrs. in both sex revealed to be the highest in frequency. 2. Suicidal accidents occurred more frequently to the unmarried(63.6%)- Among the successful suicides; higher frequency was shown to unmarried in men and the frequency is contrasted in women. Among the unsuccessful; the unmarried in both sex were revealed to be highest in frequency. 3. Schizophrenia was revealed the highest of suicidal attempts in frequency (81.8%). 4, Suicides were most frequently attempted in the spring(46, 9%). Among the successful suicides; highest frequencies were shown in men in tile winter and in women in the summer season. Among the unsuccessful suicides :highest frequencies were shown in men in the winter and in women in the spring. 5. Suicidal attempts were most frequently occurred in hospital wards (40.9%), In women, unsuccessful attempts were found to be the highest on authorized leave at their homes. 6. The hanging was revealed to be the most frequently adopted methods for suicidal attempts (31.8%). Among the successful suicides; hanging was the most frequent method adopted in men white in women the drug over-dose, Among the unsuccessful suicides ; stabbing by sharp devices while in women drug-overdosage was adopted as well 7. The most frequently adopted instrument of different suicidal attempts were: house-hold wrapper (26.3%) in cases of hanging, knives (31.8%) in cases of stabbing, and drugs. 8. The suicidal attempts have occurred most frequently at dawn through early morning (2-6A. M.) (34.8%). Among the successful suicides i most frequent time of occurrence on week-days were revealed to be dawn, while on holidays the occurrence were in the evening as well Among the unsuccessful; the most frequent time of occurrence was the day hours while on holidays at dawn. 9. Suicidal attempts within the hospital ward were first noticed by nurses most frequently (42.2%). 10. Manifestations such as restlessness, depression, self-depreciation were revealed to be the most frequent pre-suicidal attempt behavior characteristics. 11. Among the successful suicides ; manifestations of physical damage were found on the neck while among unsuccessful attempts, the damages were found on exterminates.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.329-340
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• 2006

Statement of problem: Damping of the peak force transmitted to implants has been reported by in vitro studies using impact forces on resin-veneered superstructures. Theoretical assumptions suggest that use of acrylic resin for the occlusal surfaces of a prosthesis would protect the connection between implant and bone. Therefore, the relationship between prosthesis materials and the force transmitted through the implant system also needs to be investigated under conditions that resemble the intraoral mechanical environment. Purpose: The purpose of this study was to analyze the fracture strength and modes of temporary prosthesis when a flange or occlusally extended structure were connected on the top of the abutment. Material and method: Modified abutments of winged and bulk design were made by casting the desired wax pattern which is made on the UCLA type plastic cylinder. Temporary crowns were made using templates on the modified abutments, and its fracture toughness and strain were compared to the traditional temporary prosthesis. To evaluate the effect of aging, 5.000 times of thermocycling were performed, and their result was compared to the 24hours specimen result. Results: The following conclusions were drawn from this study: 1. In the fracture toughness test, temporary crown's fracture line located next to the screw hole while modified designs with metal support showed fracture line on the metal and its propagation along the metal-resin interface. 2. Wing and bulk structure didn't show significant difference in the fracture toughness (p>0.05), but wing structure showed stress concentration on the screw hole area compared to bulk structure which showed even stress distribution. 3. In the fracture toughness test after thermocycling, wing and bulk structure showed increased or similar results in metal supported area while off-metal area and temporary crown showed decreased results. 4. In the strain measurement after thermocycling, its value increased in the temporary and bulk structure. However, wing structure showed decreased value in the loading point while increased value in the screw hole area. Conclusion: Wing type design showed compatible result to the bulk type that its application with composite resin prosthesis to the implant dentistry is considered promising.

• Journal of the Korean Wood Science and Technology
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• v.48 no.6
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• pp.780-790
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• 2020

In this study, the cell-wall microstructure and anti-swelling effectiveness (ASE) of heat-treated larch wood were evaluated and the correlation between them was analyzed. For this purpose, some larch lumbers were heat-treated for 12, 18, and 24 hours at temperatures of 190℃ and 220℃. By observing the scanning electron microscopy cross-sectional image of the heat-treated larch, it was confirmed that the shape of heat-treated wood cell changed, the cut-section of the wood cell wall was rough, and the intercellular space has become wide as the intercellular bonds had broken because of heat-treatment. In addition, the evaluation of the swelling for each treatment condition revealed that, as the heat-treatment temperature and duration increased, the amount of absorbed water and swelling decreased and the ASE increased. The decrease in the amount of absorbed water is thought to be affected by the chemical change in the cell wall by heat-treatment. On the contrary, the decrease in the swelling and the increase in the ASE are thought to be due to a combination of chemical changes and physical changes such as structural changes in the cell wall.

• Analytical Science and Technology
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• v.14 no.1
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• pp.88-93
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• 2001

To measure the levels of dioxins in food selling at local markets, meat was analyzed by high resolution gas chromatography/high resolution ass spectrometry (HRGC/HRMS). The food samples were obtained from 5 large cities of Seoul, Chunchon, Daejon, Kwangju and Busan in Korea. All the samples were minced and extracted with Soxhlet extractor for 18 hours. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on a series of silica gel, alumina, carbon column chromatography and then analyzed by HRGC/HRMS. The contaminated levels were calculated as the TEQs by multiplying with the corresponding WHO-TEFs for each congeners. The overall recoveries were ranged from 80% to 153% and the limit of detection was about 0.01 ppt at S/N>3. The levels of PCDD/Fs for beef, pork and chicken were 0.018, 0.008 and <0.001 pgTEQ/g, respectively. In addition, the levels of non-ortho-co-planar PCBs for beef, pork and chicken were 0.008, 0.002 and 0.001 pgTEQ/g, respectively. Among food samples analyzed, chicken showed the lowest level of dioxin-like compounds. Regarding congener pattern, OCDD and PCB #77 were the highest contributing congeners.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.747-754
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• 2009

In this study, adsorption isotherms of o-DCB(ortho-dichlorobenzene) on an activated carbon heated at $1000^{\circ}C$ for 24 hours were obtained by experiment and were predicted by using molecular simulation. The initial molecular structure of the activated carbon was designed on the basis of its molecular formula and functional groups ratio measured experimentally. Then, the molecular structure was optimized using the COMPASS(condensed-phase optimized molecular potentials for atomistic simulation studies) force field. The particle porosity, specific surface area, and particle density obtained from the optimized molecular structure of activated carbon were compared with those experimental data. The errors between experimental data and simulation results of the particle porosity, specific surface area, and particle density were shown as 7.6, 3.8, and 2.8%, respectively. Adsorption isotherms constants of o-DCB are calculated by the GCMC(grand canonical Monte Carlo) method in the optimized molecular structure of activated carbon. The simulation result of the adsorption isotherms showed an error of under 3%, compared to that of experimental data. Adsorption isotherms, adsorption heat and pore diffusivity of 2,3,7,8-TCDD(tetrachlorodibenzo-p-dioxin) was finally obtained in the same molecular structure of the activated carbon as used for o-DCB. Thus, adsorption characteristics of persistent organic pollutants on activated carbon, which are not easy to experimentally evaluate, are predicted by the molecular simulation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.5
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• pp.455-461
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• 2000

Malignant tumors of the head and neck frequently require treatment with both radiotherapy and surgery. Reconstruction of the defect in previously irradiated field is a challenge to surgeon, who must produce both a functional and an esthetic result. Hyperbaric oxygen therapy(HBO) has been used in an attempt to reduce the deleterious effects of radiation. But the issue of whether prior irradiation and HBO of the recipient site of a free flap affects the result of reconstruction continues to generate controversy. So, the effects of irradiation and hypergbaric oxygen therapy on microvascular anastomosis was evaluated in an experimental study in femoral vessels of rats. The experimental groups were divided into 3 groups, contorol group, irradiation group, and irradiation and HBO group. Preoperative irradiation was delivered in the left groin field with single dose corresponding 2,000cGy and total 48 hours of HBO was given 100% oxygen at 2.4 atmosphere for 4 weeks. The femoral vessels of 60 rats were anastomosed after irradiation and HBO treatment. Three days, 1 week, 2 weeks and 4 weeks after surgery, the femoral vessels were evaluated for patency and histopathologic changes. There was no notable effect of irradiation on patency of femoral vessels in rats and the radiation effects were obvious on histological examination which showed the sloughing of the endothelial cells, subintimal hyperplasia and fibrosis on the media and adventitia of femoral arteries. The histologic changes of the femoral veins were mild and not typical. But the effects of hyperbaric oxygen therapy after irradiation was seen not marked difference in irradiation group.