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Diagenetic History of the Ordovician Chongson Limestone in the Chongson Area, Kangwon Province, Korea (강원도 정선 지역 오르도비스기 정선석회암의 속성 역사)

  • Bong, Lyon-Sik;Chung, Gong-Soo
    • Journal of the Korean earth science society
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    • v.21 no.4
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    • pp.449-468
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    • 2000
  • The Ordovician Chongson Limestone deposited in the carbonate ramp to the rimmed shelf shows diverse diagenetic features. The marine diagenetic feature appears as isopachous cements surrounding ooids and peloids. Meteoric diagenetic features are recrystallized finely and coarsely crystalline calcite, evaporite casts filled with calcite, and isopachous sparry calcite surrounding ooid grains. Shallow burial diagenetic features include wispy seam, microstylolite, and dissolution seam whereas deep burial features include stylolite, burial cements. blocky calcite with twin lamellae, and poikilotopic calcite. Dolomites consist of very finely to finely crystalline mosaic dolomite formed as supratidal dolomite, disseminated dolomite of diverse origin, patchy dolomite formed from bioturbated mottles, and saddle dolomite of burial origin. Silicified features include calcite-replacing quartz and fracture-filling megaquartz. Burial cements characterized by poikilotopic texture show ${\delta}^{18}$O value of -10.4 %$_o$ PDB, ${\delta}^{13}$C value of -1.0%$_o$ PDB and 504ppm Sr, 3643ppm Fe, and 152ppm Mn concentrations. Finely and coarsely crystalline limestones show similar ${\delta}^{18}$O and ${\delta}^{13}$C value to those of burial cements; however, they show lower Sr and higher Fe and Mn concentrations than burial cements. This suggests that very finely and coarsely crystalline limestones were recrystallized in freshwater and then they were readjusted geochemically in the burial setting whereas the burial cements were formed in relatively high temperature and low water/rock ratio conditions. Very finely and finely crystalline mosaic dolomites with ${\delta}^{18}$O value of -8.2%$_o$ PDB, ${\delta}^{13}$C value of -1.9 %$_o$ PDB, and 213ppm Sr, 3654ppm Fe, and 114ppm Mn concentrations, respectively are interpreted to have been formed penecontemporaneously in supratidal flat and then recrystallized in the low water/rock ratio burial environment. Geochemical data suggest that the low water/rock ratio burial environment was the dominant diagenetic setting in the Chongson Limestone. The Chongson Limestone has experienced marine and meteoric diagenesis during early diagenesis. With deposition of Haengmae and Hoedongri formations part of the Chongson Limestone was buried beneath these formations and it experienced shallow burial diagenesis. During the Devonian the Chongson Limestone was tectonically deformed and subaerially exposed. During the Carboniferous to the Permian about 3.3km thick Pyongan Supergroup was deposited on the Chongson Limestone and the Chongson Limestone was in deep burial depths and stylolite, burial cements, blocky calcite and saddle dolomite were formed. After this burial event the Chongson Limestone was subaerially exposed during the Mesozoic and Cenozoic by three periods of tectonic disturbance including Songnim, Daebo and Bulguksa disturbance. Since the Bulguksa disturbance during Cretaceous and early Tertiary the Chongson Limestone has been subaerially exposed.

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Protective Effects of Chemical Drugs on the Course of Uranium-induced Acute Renal Failure (우라늄오염에 의한 신부전증에 미치는 제염제의 방호효과)

  • Kim, Tae-Hwan;Chung, In-Yong;Kim, Sung-Ho;Kim, Kyeng-Jung;Bang, Hyo-Chang;Yoo, Seong-Yul;Chin, Soo-Yil
    • Journal of Radiation Protection and Research
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    • v.15 no.2
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    • pp.27-39
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    • 1990
  • Appreciable radiation exposures certainly were occurred in the reactor burn-up, the nuelear fall-out and the surroundings of nuclear installations with radioactive effluents. Therefore, radioactive nuclides is not only potentially hazardous to workers of nuclear power plants and related industrials, but also the wokers who handle radioactive nuclides in biochemical research and nuclear medicine diagnostics. And in the case of occurring the nuclear accidents, the early medical treatment of radiation injury should be necessary but little is established medical procedures to decontaminate the victims of internal contamination of radioactive nuclides in korea. Accordingly, to achieve the basic data for protective roles and medical treatment of radiation injury, the present studies were carrid out to evaluate the decontamination of uranium by the chemical drugs. The results observed were summarized as follows: 1. The combined treatmet group of sodium bicarbonate and saline with uranyl nitrate injection simultaneously and the dithiothreitol group that was administered 30 minutes after uranyl nitrate injection were increased significantly in the change of body weight than uranyl nitrate-only group (P<0.005). 2. All the experimental groups were increased the fluid intake and urine volume on the uranyl nitrate-induced acute renal failure. but the combined treatment group of sodium bicarbonate and saline with uranyl nitrate injection simultaneously and the dithiothreitol group that was administered 30 minutes after uranyl nitrate injection have the higher increment of fluid intake and urine volume (P<0.05). 3. When sodium bicarbonate and saline was treated with uranyl nitrate injection simultaneously. and dithiothreitol was administered 30 minutes after uranyl nitrate injection. there was significantly reduced in BUN concentration (P<0.01). 4. When dithiothreitol was administered 30 minutes after uranyl nitrate injection. there was reduced more significantly on the increment of serum creatinine concentration than that observed in uranyl nitrate-only group(P<0.01). but when the combined treatment of sodium bicarbonate and saline with uranyl nitrate simultaneously, there was still. albeit much less marked. decrease in serum creatinine concentration. 5. The sodium bicarbonate and saline was treated with uranyl nitrate simultaneously and dithiothreitol was administered at 30 minutes after uranyl nitrate were excreted markedly higher urine creatinine concentration than the uranyl nitrate-only group. 6. Uranyl nitrate has been used in experimental animals to produce hydropic degeneration and swelling of proximal tubules, disappearance of microvilli and brush border or necrosis in the kidney and centrilobular necrosis, congestion, and telangiectasia of the liver. When the sodium bicarbonate and saline was treated with uranyl nitrate simultaneously, and dithiothreitol was administered. 30 minutes after uranyl nitrate, there was more marked the protective effect than uranyl nitrate-only group. Finally, if the sodium bicarbonate and saline may administered as quickly as possible each time that some risk for internal contamination, with uranium, and dithiothreitol is administered 30 minutes after uranium contamination, there ameliorates the course of uranyl nitrate-induced acute renal failure.and this effect is assocciated with prevention of uranium (heavy metal)-induced alterations in BUN, serum creatinine, urine creatinine, fluid intake, urine volume and body weight.

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Genetic Polymorphisms of the $\beta_2$-Adrenergic Receptor in the Severity of Bronchial Asthma (기관지 천식 환자에서 천식 증상의 정도에 따른 $\beta_2$ 교감신경 수용체의 유전자 다형성)

  • Shim, Jae-Jeong;Kim, Jei-Hyung;Lee, Seung-Yong;Kwan, Young-Hwan;Lee, So-Ra;Lee, Sang-Youb;Kang, Se-Yong;Kang, Yong-Koo;Cho, Jae-Youn;In, Kwang-Ho;Won, Nam-Hee;Yoo, Se-Hwa;Kang, Kyung-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.1
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    • pp.77-89
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    • 1998
  • Background: Genetic and environmental factors are known to affect the incidence and severity of asthma. Stimulation of $\beta_2$-Adrenergic Receptor ($\beta_2$AR) results in smooth muscle relaxation, leading to decrease in resistance of airflow. The gene encoding the $\beta_2$AR has recently been seguenced. The $\beta_2$AR genotype at the polymorphic loci of codons 16, 27, 34, and 164 was known to cause changes in the amino acids. The relationships between the structure of the $\beta_2$AR and its functions are being elucidated. Purpose : The gene encoding the $\beta_2$AR was carried out to assess the frequency of polymorphisms in bronchial asthma, to determine wheather these polymorphisms have any relation to the severity, or nocturnal symptoms in bronchial asthma. Methods: The subjects studied were 103 patients with bronchial asthma, which consisted of 30 mild episodic, 32 mild persistent, 17 moderate, and 24 severe asthma patients. The polymorphisms of the $\beta_2$AR gene were detected by mutated allele specific amplification (MASA) method at the codons 16,27,34, and 164. Results: The most frequent polymorphism was arginine 16 to glycine. The other two polymorphisms, valine 34 to methionine and glutamine 27 to glutamic acid occured in 11 and 6 patients respectively. The polymorphism of threonine 164 to isoleucine was not found in our enrolled patients. The homozygous polymorphism of $\beta_2$AR gene was found in only arginine 16 to glycine (12.6%). The heterozygous polymorphisms of $\beta_2$AR gene were in arginine 16 to glycine, valine 34 to methionine, and glutamine 27 to glutamic acid, as 65.1 %,10.7%, and 5.8% respectively in asthma patients. The presence of agrginine 16 to glycine heterozygous or/and homozygous polymorphism was associated in severe asthma (p=0.015), but there was no association between the other three polymorphisms and the severity of asthma. The frequency of the $\beta_2$AR gene polymorphisms was no relation in nocturnal asthma as compared with non-nocturnal asthma. Conclusion: The arginine 16 to glycine polymorphism of the $\beta_2$AR gene is the most frequently found in asthma patients and association with severe asthma. But there was no association between the polymorphism of the $\beta_2$AR gene and nocturnal asthma.

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The Effect of Glucocorticoid on the Change of Nitric Oxide and Cytokine Levels in Induced Sputum from Patients with Bronchial Asthma (기관지 천식 환자에서 부신피질 스테로이드 투여 전후 유도객담내 Nitric Oxide 및 Cytokine의 변화)

  • Kim, Tae-Yon;Yoon, Hyeong-Kyu;Choi, Young-Mee;Lee, Sook-Young;Kwon, Soon-Seog;Kim, Young-Kyoon;Kim, Kwan-Hyoung;Moon, Hwa-Sik;Park, Sung-Hak;Song, Jeong-Sup
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.6
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    • pp.922-931
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    • 2000
  • Background : It has been well known that bronchia1 asthma is a chronic airway inflammatory disorder. Recently, sputum induced with hypertonic saline was introduced as a simple and useful nonivasive medium to investigate airway inflammation and symptom severity in patients with asthma. We examined the eosinophil, eosinophil cationic protein (ECP), interleukin(IL)-3, IL-5, granulocyte-macrophage colony-stimulating facta (GM-CSF), and nitric oxide (NO) derivatives in induced sputum from patients with bronchia1 asthma in order to determine the role of NO and various inflammatory cytokines as a useful markers of airway inflammation or changes in pulmonary function tests and symptoms. Methods : A total 30 patients with bronchia1 asthma received oral prednisolone 30 mg daily for 2 weeks. Forced expiratory volume in one second ($FEV_1$), total blood eosinophil count and induced sputum eosinophil count, ECP, IL-3, IL-5, GM-CSF, and NO derivatives were determined before and after the administration of prednisolone. Results : Of the 30 patients, 13 (43.3%) were male and 17 (56.7%) were female. The mean age of patients was 41.8 years (range 19-64 years). Two patients could not produce sputum at the second study and 3 could not be followed up after their first visit. Two weeks after the prednisolone administration, there was a significant increase in $FEV_1$ (% of predicted value) from 78.1$\pm$20.6 % to 90.3$\pm$ 18.3 % (P<0.001). The eosinophil percentages in induced sputum were significantly decreased after treatment with prednisolone, with values of 56.1$\pm$27.2 % versus 29.6$\pm$21.3 % (P<0.001), and ECP were $134.5\pm68.1\;{\mu}g/L$ versus $41.5\pm42.4\;{\mu}g/L$ (P<0.001) respectively. After the prednisolone treatments, the eotaxin concentration also showed a decreasing tendency from 26.7$\pm$12.8 pg/ml to 21.7$\pm$8.7 pg/ml. There was a decreasing tendency but no significant differences in total blood eosinophil count (425.7$\pm$265.9 vs 287.7$\pm$294.7) and in the concentration of NO derivatives ($70.4\pm44.6{\mu}mol/L$ vs $91.5\pm48.3\;{\mu}mol/L$) after the prednisolone treatments. IL-3, IL-5, GM-CSF were undetectable in the sputum of most subjects either before the prednisolone treatments or after the treatments. Before the prednisolone treatments, a significant inverse correlation was observed between FEV1 and sputum ECP (r=-D.364, P<0.05) and there was a significant correlation between sputum eosinophils and eotaxin (r=0.369, P<0.05) Conclusion : The eotaxin and ECP concentration in induced sputum may be used as markers of airway inflammation after treatments in bronchia1 asthma. In addition, the measurement of sputum eosinophil percent ages is believed to be a simple method displaying the degree of airway inflammation and airway obstruction before and after the prednisolone treatment in bronchia1 asthma. However, unlike exhaled NO, the examination of NO derivatives with Griess reaction in induced sputum is considered an ineffective marker of changing airway inflammation and obstructing symptoms.

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Effect of Short-term Nutrition Education Camp on Food and Nutrient Intakes of Obese Children (단기간 영양교육 캠프가 비만아동의 식품과 영양소 섭취에 미치는 영향)

  • Shin, Eun-Kyung;Lee, Jin-Hwa;Lee, Yeon-Kyung;Lee, Hye-Sung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.7
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    • pp.987-999
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    • 2005
  • The purpose of this study was to evaluate the effect of short-term nutrition education camp on food and nutrient intakes of obese children. The subjects of the study were 30 obese children in Gumi city who have obesity index over $130\%$. The food consumption of the subjects was surveyed for three days before the camp, for eleven days during the first camp and for three days after the second camp, by food record method. The mean intakes of energy and carbohydrates in obese children were significantly decreased during and after the nutrition education camp, and that of vitamin C was significantly increased after the camp. The mean daily total food intake of the subjects was gradually decreased from 1646.4g before the camp to 1438.6g during the camp and 1412.66g after the camp. Energy and fat intake ratios from grains and milks were significantly decreased after the camp compared with that before the camp, and the energy intake ratio from grains, milks and eggs was significantly low during the camp. The protein intake ratios from grains, potatoes, vegetables and fishes were significantly increased after the camp. The calcium intake ratios from potatoes and milks were significantly increased during and after the camp, and the ratio from eggs was significantly decreased after the camp. The iron intake ratios from potatoes and fishes were significantly increased during and after the camp, and the ratio from grains was significantly low during the camp. The results of the study demonstrated that the short-term nutrition education program positively affected the overall food consumption and nutrients intakes of obese children.

Changes in Nitrogenous Compounds of Soybean during Chungkookjang Koji Fermentation (청국장(淸國醬) 발효중(醱酵中) 질소화합물(窒素化合物)의 변화(變化))

  • Sung, Nak-Ju;Ji, Young-Ae;Chung, Seung-Yong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.13 no.3
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    • pp.275-284
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    • 1984
  • In order to study the flavor quality of Chungkookjang, the changes in nitrogenous compounds, nucleotides and their related compounds, free amino acids, amino acid composition and fatty acids were analysed during Chungkookjang Koji fermentation. Koji was prepared with Bacillus natto isolated from Japanese natto. Insoluble nitrogenous was rapidly decreased, whereas PAA (peptide, amino, ammonia) nitrogen were slightly increased during the fermentation of Chungkookjang Koji. The content of extracted nitrogen and free amino acid nitrogen were rapidly increased until 48 hours fermentation of Chungkookjang Koji and then decreased. The contents of ADP, ATP, AMP and inosine in raw soybean were abundant. The contents of ADP, ATP and AMP were decreased while inosine and hypoxanthine were increased during the fermentation of Chungkookjang Koji. The free amino acids analyzed in this experiment were not changed in composition but changed in amounts during the fermentation of Chungkookjang Koji. The contents of alanine, valine, isoleucine and phenylalanine were continually increased during the fermentation of Chungkookjang Koji. The contents of lysine, histidine, arginine, glutamic acid, glycine, methionine and tyrosine were increased until 48 hours fermentation and then decreased gradually. The increase in the contents of aspartic acid, threonine, serine, proline and cystine were fluctuated. In raw soybean, amino acid composition such as glutamic acid, serine and proline were dominant amino acid and amounts those were 63.8% of the total amino acids. The contents of aspartic acid, proline, glycine, alanine, cystine, leucine and tyrosine were continually decreased during the fermentation of Chungkookjang Koji, arginine and methionine were increased until 48 hours fermentation of Chungkookjang Koji and then decreased gradually. The increase of threonine and serine were fluctuated. Eight kinds of fatty acids were detected from raw soybean, but 10 kinds of fatty acids detected from Chungkookjang Koji. Palmitic, oleic and linoleic acid were identified as the major fatty acid of raw soybean and Chungkookjang Koji, and amounts of those were estimated above 80% of the total fatty acids.

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Comparison of Early Germinating Vigor, Germination Speed and Germination Rate of Varieties in Poa pratensis L., Lolium perenne L. and Festuca arundinacea Schreb. Grown Under Different Growing Conditions (생육환경에 따른 Poa pratensis L., Lolium perenne L. 및 Festuca arundinacea Schreb.의 초종 및 품종별 발아세, 발아속도 및 발아율 비교)

  • 김경남;남상용
    • Asian Journal of Turfgrass Science
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    • v.17 no.1
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    • pp.1-12
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    • 2003
  • Research was Initiated to investigate germination characteristics of cool-season grasses (CSG). Several turfgrasses were tested in different experiments. Experiments I and III were conducted under a room temperature condition of 16$^{\circ}C$ to 23 $^{\circ}C$ and under a constant light condition at 25 $^{\circ}C$, respectively. An alternative environment condition that is a requirement for a CSG germination test by International Seed Testing Association (ISTA) was applied in the Experiment II, consisting of 8-hr light at 25 $^{\circ}C$ and 16-hr dark at 15 $^{\circ}C$. In each experiment, data such as early germinating vigor, germination speed and germination rate were evaluated. Six turfgrass entries were comprised of two varieties each from Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.), respectively. Significant differences were observed in early germinating vigor, germination speed and germination rate. Early germinating vigor as measured by days to 70% seed germination was variable according to environment conditions, turfgrasses and varieties. It was less than 6 days in PR and 6 to 9 days in TF. However, KB resulted in 11 to 13 days under an alternative condition and 11 to 28 days under a room temperature condition. The germination speed was fastest in PR of 7 to 10 days and slowest in KB of 14 to 21 days. However, intermediate speed of 10 to 14 days was associated with TF. There were considerable variations in germination rate among turfgrasses according to different conditions. Generally, PR and TF germinated well, regardless of environment conditions. However, a great difference was observed among KB varieties, when compared with others. Under a room temperature condition, total germination rate was 71.0% in Midnight and 77.7% in Award. And it increased under an alternative condition, which was 81.7% and 91.7% in Award and Midnight, respectively. However, the poorest rate was found under a constant temperature condition, resulting in 18.0% in Award and 15.3% in Midnight. These results suggest that an intensive germination test required by ISTA be needed prior to the decision of seeding rate, including early germinating vigor and germination speed as well as total germination rate. KB is very sensitive to environment conditions and thus its variety selection should be based on a careful expertise.

The Effect of Two Terpenoids, Ursolic Acid and Oleanolic Acid on Epidermal Permeability Barrier and Simultaneously on Dermal Functions (우솔릭산과 올레아놀산이 피부장벽과 진피에 미치는 영향에 대한 연구)

  • Suk Won, Lim;Sung Won, Jung;Sung Ku, Ahn;Bora, Kim;In Young, Kim;Hee Chang , Ryoo;Seung Hun, Lee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.2
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    • pp.263-278
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    • 2004
  • Ursolic acid (UA) and Oleanolic acid (ONA), known as urson, micromerol and malol, are pentacyclic triterpenoid compounds which naturally occur in a large number of vegetarian foods, medicinal herbs, and plants. They may occur in their free acid form or as aglycones for triterpenoid saponins, which are comprised of a triterpenoid aglycone, linked to one or more sugar moieties. Therefore UA and ONA are similar in pharmacological activity. Lately scientific research, which led to the identification of UA and ONA, revealed that several pharmacological effects, such as antitumor, hepato-protective, anti-inflammatory, anticarcinogenic, antimicrobial, and anti-hyperlipidemic could be attributed to UA and ONA. Here, we introduced the effect of UA and ONA on acutely barrier disrupted and normal hairless mouse skin. To evaluate the effects of UA and ONA on epidermal permeability barrier recovery, both flanks of 8-12 week-old hairless mice were topically treated with either 0.01-0.1mg/mL UA or 0.1-1mg/mL ONA after tape stripping, and TEWL (transepidermal water loss) was measured. The recovery rate increased in those UA or ONA treated groups (0.1mg/mL UA and 0.5mg/mL ONA) at 6h more than 20% compared to vehicle treated group (p < 0.05). Here, we introduced the effects of UA and ONA on acute barrier disruption and normal epidermal permeability barrier function. For verifying the effects of UA and ONA on normal epidermal barrier, hydration and TEWL were measured for 1 and 3 weeks after UA and ONA applications (2mg/mL per day). We also investigated the features of epidermis and dermis using electron microscopy (EM) and light microscopy (LM). Both samples increased hydration compared to vehicle group from 1 week without TEWL alteration (p < 0.005). EM examination using RuO4 and OsO4 fixation revealed that secretion and numbers of lamellar bodies and complete formation of lipid bilayers were most prominent (ONA=UA > vehicle). LM finding showed that thickness of stratum corneum (SC) was slightly increased and especially epidermal thickening and flattening was observed (UA > ONA > vehicle). We also observed that UA and ONA stimulate epidermal keratinocyte differentiation via PPAR Protein expression of involucrin, loricrin, and filaggrin increased at least 2 and 3 fold in HaCaT cells treated with either ONA (10${\mu}$M) or UA (10${\mu}$M) for 24 h respectively. This result suggested that the UA and ONA can improve epidermal permeability barrier function and induce the epidermal keratinocyte differentiation via PPAR Using Masson-trichrome and elastic fiber staining, we observed collagen thickening and elastic fiber elongation by UA and ONA treatments. In vitro results of collagen and elastin synthesis and elastase inhibitory activity measurements were also confirmed in vivo findings. These data suggested that the effects of UA and ONA related to not only epidermal permeability barrier functions but also dermal collagen and elastic fiber synthesis. Taken together, UA and ONA can be relevant candidates to improve epidermal and dermal functions and pertinent agents for cosmeseutical applications.

The Effects of Silicate Nitrogen, Phosphorus and Potassium Fertilizers on the Chemical Components of Rice Plants and on the Incidence of Blast Disease of Rice Caused by Pyricularia oryzae Cavara (규산 및 삼요소 시비수준이 도체내 성분함량과 도열병 발생에 미치는 영향)

  • Paik Soo Bong
    • Korean journal of applied entomology
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    • v.14 no.3 s.24
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    • pp.97-109
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    • 1975
  • In an attempt to develop an effective integrated system of controlling blast disease of rice caused by Pyricularia oryzae Cav., the possibility of minimizing the disease incidence by proper application of fertilizers has been investigated. Thus the effect of silicate, nitrogen, phosphorus and potassium fertilizers on the development of blast disease as well as the correlation between the rice varieties an4 strains of P. oryzae were studied. The experiments were made in 1971 and 1973 by artificial inoculation and under natural development of the blast disease on rice plants. The results obtained are summarized as follows. 1. Application of silicate fertilizer resulted in the increase of silicate as well as total sugar and potassium content but decrease of total nitrogen and phosphorus in tile leaf blades of rice plants. 2. The ratios of total C/total N. $ SiO_2/total$ N, and $K_2O/total$ N in leaf blades of rice plants increased by the application of silicate fertilizers. There was high level of negative correlation between the ratios mentioned above and the incidence of rice blast disease. 3. Application of silicate fertilizer reduced the incidence of rice blast disease. 4. The over dressing of nitrogen fertilizer resulted in the increase of total nitrogen and decrease of silicate and total sugar content in leaf blades, thus disposing the rice plants more susceptible to blast disease. 5. Over dressing of phosphorus fertilizer resulted in the increase of both total nitrogen and Phosphorus, and decrease of silicate content in the leaf blades inducing the rice plants to become more susceptible to blast disease. 6. Increased dressing of potash resulted in the increase of silicate content and $K_2O/total$ N ratio but decrease of total nitrogen content in leaf blades. When potassium content is low in the leaf blades of rice plants, the additional dressing of potash to rice plant contributed to the increase of resistance to blast disease. However, there was no significant correlation between additional potassium application and the resistance to blast disease when the potassium content is already high in the leaf blades. 7. When four rice varieties were artificially inoculated with three strains of P. oryzae, the incidence of blast disease was most severe on Pungok, least severe on Jinheung and moderate on Pungkwang and Paltal varieties. 8. Disease incidence was most severe on the second leaf from top and less sever on top and there leaf regardless of the fertilizer application when 5-6 leaf stage rice seedlings of four rice varieties were artificially inoculated with three strains of P. oryzae. 9. The pathogenicity of three strains of P. oryzae was in the order of $P_1,\;P_2,\;and\;P_3$ in their virulence when inoculated to Jinheung, Paltal, Pungkwang varieties but not with Pungok. The interaction between strains of P. oryzae and rice varieties was significant.

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A Study on Corrosion according to Distance between Amalgam and Dissimilar Metals (아말감과 이종(異種)금속의 거리에 따른 부식에 대한 고찰)

  • Kim, Ju-won;Jeong, Eun-gyeong
    • Journal of dental hygiene science
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    • v.4 no.3
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    • pp.103-109
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    • 2004
  • The present study prepared 72 test samples - 24 made of amalgam alloy, 24 of Verabond (Ni-Cr alloy) for crown and 24 of Talladium $^{TM}alloy$ for denture - according to the manufacturers' manuals and general method in consideration of the width of the mesial-distal dental crown of the lower $1^{st}$ molar and MOD cavity in clinics, put them in a 200 ml beaker containing 80 ml of artificial saliva, and measured their galvanic corrosion at distances of 0 mm, 7 mm and 40 mm after 7 days. Isolated metals in the electrolyte such as Cu, Ag, Ni, Cr, Sn, Zn and Hg were quantitatively analyzed with Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES, JY-50P, VG Elemental Co. France), and from the results were drawn conclusions as follows. First, Cu, Sn, Ag, Hg and Zn were highly advantageous when amalgam contacted gold alloy compared to Ni-Cr alloy for crown and Talladium alloy for denture. In addition, although gold alloy was finest in terms of oral tissue and biocompatibility, it was most disadvantageous when it was with amalgam. Second, when amalgam contacted gold alloy, heavy metals such as Ni and Cr were not isolated at all because gold alloy did not contain such elements but Sn was isolated as much as $227.1{\pm}18.0035{\mu}g/cm^2$ although it was not included in the composition either. Hg was also isolated. These elements are assumed to have been isolated from amalgam itself. Third, when amalgam alloy was apart from gold alloy 0 mm, 7 mm and 40 mm, Cu and Ag showed significance but Hg did not. This suggests that gold alloy must not be used together with amalgam, and must not be used between dissimilar prostheses regardless of distance. Fourth, when amalgam alloy contacted Ni-Cr alloy for crown, Ag was not isolated from the amalgam, but Zn, Ni, Sn, Hg and Cu were isolated in order of quantity. Significance was observed according to distance - 0 mm, 7 mm and 40 mm. Hg was not isolated but heavy metals Ni and Cr were isolated. If amalgam alloy was in the opposite arch or it was apart from Ni-Cr alloy for crown, the isolation Hg was less than that when amalgam alloy contacted Ni-Cr alloy for crown. Fifth, when amalgam alloy contacted Talladium alloy for denture, significance was observed at distances of 0mm, 7 mm and 40 mm. Hg was not isolated but heavy metals Ni and Cr were isolated. If amalgam alloy was in the opposite arch or it was apart from Talladium alloy for denture, the isolation Hg was less than that when amalgam alloy contacted Talladium alloy for denture. Sixth, according to the result of ICPES test on Cu, Sn, Ag, Hg, Zn, Ni and Cr of amalgam alloy, gold ally, Verabond and Talladium alloy when these alloys contacted artificial saliva, significance was observed in Cu and Hg. Seventh, when amalgam alloy contracted two non-precious metals Ni-Cr alloy for crown and Talladium alloy for denture in artificial saliva, significance was observed in the isolated by-products of Hg, Ni and Cr according to distance.

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