• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.191-199
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• 2015

We conducted this research to observe the changes of surface morphology and composition of clay minerals influenced by various concentrations of fluoric acid. Hydrofluoric acid (HA), a solution of hydrogen fluoride (HF) in water, is a colourless solution that is highly corrosive, capable of dissolving many materials, especially oxides. To do this, we treated several concentrations of HA on the ground soil samples collected from the agricultural experimental station located at Chungnam National University to observe the influence of fluoric acid on the changes of surface structures and elemental composition of clay particles. Generally, microscopic examination showed that the HA can not only attack an edge of clay particles but also start at any point where structural defects and weaknesses predisposed sites to acid. The orderly flake arrangement of clay minerals may reflect certain crystal symmetry elements. The ESEM-EDS results of element composition of clay particles influenced by HA indicated the changes of structures of clay minerals. It is also clear from the formation of etch figures and element composition of clay particles that the product layer at least partially dissolved or disintegrated in the presence of acid. Conclusively, the clay structures can be strongly influenced by concentrations of HA, resulting in changes of physical and chemical properties that can determine the behavior of solute transport as well as mobility of ions in soils.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.107-113
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• 2014

This study was conducted to evaluate the association between periodontal disease and diabetes mellitus. The final analysis population of this study was composed of 4,830 adults with diabetes mellitus or periodontal disease and aged 19 years or older, based on the third-edition data of the 4th Korea National Health and Nutrition Examination Survey (KNHANES) (in 2009). Diabetic status and potential confounders were used in questionnaire materials and physical examination materials, and the presence of periodontal disease was used in the materials for oral health examination by a dentist. For diabetic status, fasting plasma glucose (FPG) levels <100 mg/dl were subcategorized into normal group and FPG levels ${\geq}100mg/dl$ into impaired fasting glucose group; glycosylated hemoglobin (HbA1c) levels <7% into normal group and HbA1c ${\geq}7%$ into diabetes group, on the basis of the American Diabetes Association. According to the 2009 Korea Health Statistics, the case where the pocket depth is 3 mm or more was defined as periodontal disease. The association between the two diseases was evaluated through $x^2$-test and logistic regression analysis using R-commander 2.14. In impaired fasting glucose group, community periodontal index (CPI) groups 3 to 4 had higher risks for periodontal disease 1.23 times (95% confidence interval, 1.07~1.42) than those of CPI groups CPI 0~2, even after adjustment for several confounders. In addition, periodontal disease and diabetes mellitus showed statistically significant differences depending on age, sex, income level, educational background, smoking status, alcohol consumption, and snack intake. The analyses of the third-edition data of the 4th KNHANES showed that there was a statistically significant association between periodontal disease and diabetes mellitus as examined by means of CPI in this study.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.75-82
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• 1996

Acrylic acid was graft-copolymerized on polyethylene film in the presence of additives such as acid and $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ using peroxide grafting technique by ${\gamma}$-ray and electron beam, and the effect of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ and acid on the grafting yield was evaluated. The grafting mechanism and the physical property of grafted films were also examined. The results showed that the inclusion of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ in acidified acrylic acid grafting solution was extremely beneficial and led to a most unusual enhancement effect in the radiation grafting. In the other hand, inclusion of mineral acid in the grafting solution in the absence of $FeSO_4(NH_4)_2SO_4{\cdot}6H_2O$ could not lead to he suitable grafting reaction by the severe homopolymerization of acrylic acid. The addition of $H_2SO_4$, and HCl led to much higher grafting yield than $HNO_3$and $CH_3COOH$. It was shown that grafting yield of ${\gamma}$-ray irradiated-polyethylene was higher than that of electron beam irradiated polyethylene.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.3
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• pp.327-333
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• 2016

Tourette's syndrome is a chronic neuropsychiatric disorder characterized by the presence of vocal and multiple motor tics. Tics are defined as brief, intermittent, repetitive, unpredictable, purposeless, and stereotyped movements or sounds. Some patients experience physical pain from intense and complex tics. In addition, motor tics can result in self-injury which is a common feature of Tourette's syndrome. A 9-year-old boy was referred by the department of neuropsychiatry because of a severe tongue laceration. His parents reported that he had been biting his tongue irregularly for 2 months before referral and suffered from an intense burning sensation. The repeated biting resulted in ulcers on the tongue, which quickly worsened and led to progressive difficulty chewing and swallowing food. We offered to give him a two-piece removable appliance to limit tongue biting; it was made of soft silicone and fitted to both the maxillary and mandibular arches. As we emphasized that the device could help alleviate his pain, he agreed to accept it and adapted well. Just 3 weeks later, his tongue lesions had healed significantly.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.372-380
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• 2004

Cleidocranial dysplasia(CCD) is a congenital disorder of skeletal and dental abnormality, which is mesodermal dysfunction influencing many tissues and organs. Skeletal abnormalities in CCD are delayed closure of cranial suture and fontanelle, presence of wormian bone and clavicle aplasia. And CCD has an effect on the long bones, phalanges, spine, pelvis, muscles, and central nervous system. Dental manifestations include retention of deciduous teeth, multiple supernumerary teeth, delayed or absent eruption of permanent teeth and formation of cysts around nonerupted teeth. But as a result in common with a lack of medical and physical disability patient may have no substantive complaint, there are many masticatory and psychological problem by absent eruption of permanent teeth after exfoliation of deciduous teeth. For this reason CCD is necessary fo early diagnosis and must be improvement of the patient's appearance as well as provision of a functioning masticatory mechanism by treatment of surgical removal of supernumerary teeth, followed orthodontically eruption of the natural permanent teeth at adequate time.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.456-463
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• 2009

Cleidocranial dysplasia(CCD) is a congenital disorder of skeletal and dental abnormality, which is a mesodermal dysfunction influencing many tisssues and organs. Skeletal abnormalities in CCD are delayed closure of cranial suture and fontanelle, presence of wormian bone and clavicle aplasia. CCD also has an effect on long bones, phalanges, spine, pelvis, muscles, and central nervous system. Dental manifestations include retention of deciduous teeth, multiple supernumerary teeth, delayed eruption or impaction of permanent teeth and formation of cysts around nonerupted teeth. However, due to lack of any substansive medical or physical disability, diagnosis is often late, thereby causing masticatory and psychological problems caused by delayed eruption of permanent teeth after exfoliation of deciduous teeth. For this reason, CCD requires early diagnosis, and the patient's appearance must be improved. Also, provision for a functional masticatiory mechanism by treatment of surgical removal of supernumerary teeth followed by orthodontic eruption of the natural permanent teeth at an adequate time is necessary.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.269-279
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• 2000

Alfalfa mosaic alfamoviruses(AIMV) were isolated from infected potato (Solanum tuberosum) and azuki bean (Paseolus angularis) in Korea. Two AIMV isolated from potatoes were named as strain KR (AIMV-KR1 and KR2) and AIMV isolated from azuki bean was named as strain Az (AIMV-Az). Each isolated AIMV strain was characterized by using their host ranges, symptom developments, serological relations and nucleotide sequence analysis of coat protein (CP) gene. Strains KR1, KR2, and Az were readily transmitted to 20 of 22 inoculated plant species including bean, cowpea, tomato, tobacco, and potato. AIMV-KR1 and KR2 produced the typical symptoms like chlorotic or necrotic spots in Chenopodium quinoa and Solanum tuberosum cv. Superior. AIMV-Az caused bright yellow mosaic symptom and leaf malformation in Nicotiana glauca, which were different from the common mosaic symptom caused by AIMV-KR1 and KR2. Electron microscope observation of purified virus showed bacilliform virions containing a single-stranded plus-strand RNAs of 3.6, 2.6, 2.0 and 0.9 kbp in length, respectively, similar in size and appearance to those of Alfamovirus. In SDS-PAGE, the coat protein of the two viruses formed a consistent band that estimated to be about 24kDa. The CP genes of the AIMV strains, KR1, KR2, and Az have been amplified by RT-PCR using the specific primers designed to amplify CP gene from viral RNA-3, cloned and sequenced. Computer aided analysis of the amplified cDNA fragment sequence revealed the presence of a single open reading frame capable of encoding 221 amino acids. The nucleotide and peptide sequence of viral CP gene showed that strain KR1, KR2, and Az shared highest nucleotide sequence identities with AIMV strain 425-M at 97.7%, 98.2%, and 97.2%, respectively. CP gene sequences of two strains were almost identical compared with each other. Altogether, physical, serological, biological and molecular properties of the purified virus.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.383-391
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• 2013

A number of true triaxial tests on rock samples have been conducted since the late 1960 and their results strongly suggest that the intermediate principal stress has a considerable effect on rock strength. Based on these experimental evidence, various 3-D rock failure criteria accounting for the effect of the intermediate principal stress have been proposed. Most of the 3-D failure criteria, however, are focused on the phenomenological description of the rock strength from the true triaxial tests, so that the associated strength parameters have little physical meaning. In order to confirm the likelihood that the intermediate principal stress dependency of rock strength is related to the presence of weak planes and their distribution to the preferred orientation, true triaxial tests are simulated with the transversely isotropic rock model. The conventional Mohr-Coulomb criterion is extended to its anisotropic version by incorporating the concept of microstructure tensor. With the anisotropic Mohr-Coulomb criterion, the critical plane approach is applied to calculate the strength of the transversely isotropic rock model and the orientation of the fracture plane. This investigation hints that the spatial distribution of microstructural planes with respect to the principal stress triad is closely related to the intermediate principal stress dependency of rock strength.

• Journal of environmental and Sanitary engineering
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• v.7 no.2
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• pp.95-110
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• 1992

Much progress has been made in understanding the subcellular events of the human lung injuries after acute exposure to environmental air pollutants. Host of those events represent oxidative damages mediated by reactive oxygen species such as superoxide, hydrogen peroxide, and the hydroxy, free radical. Recently, nitric oxide (NO) was found to be endogenously produced by endothelial cells and cells of the reticulo-endothelial system as endothelialderived relaxation factor (EDRF) which is a vasoactive and neurotransmitter substance. Together with superoxide, NO can form another strong oxidant, peroxonitrite. The relative importance of exogenous sources of $N0/N0_2$ and endogenous production of NO by the EDRF producing enzymes in the oxidative stresses to the heman lung has to be elucidated. The exact events leading to chronic irreversible damage are still yet to be known. From chronic exposure to oxidant gases, progressive epithelial and interstitial damages develop. Type I epithelial cells become thicker and cover a smaller average alveolar surface area while thee II cells proliferate instead. Under acute damages, the extent of loss of the alveolar epithelial cell lining, especially type II cells appears to be a good predictor of the ensuing irreversible damage to alveolar compartment. Interstitial matrix undergo remodeling during chronic exposure with increased collagen fibers and interstitial fibroblasts. However, Inany of these changes can be reversed after cessation of exposure. Among chronic lung injuries, genetic damages and repair responses received particular attention in view of the known increased lung cancer risks from exposure to several air pollutants. Heavy metals from foundry emission, automobile traffics, and total suspended particulate, especially polycystic aromatic hydrocarbons have been positively linked with the development of lung cancer. Asbestos in another air pollutant with known risk of lung cancer and mesothelioma, but asbestos fibers are nonauthentic in most bioassays. Studies using the electron spin resonance spin trapping method show that the presence of iron in asbestos accelerates the production of the hydroxy, radical in vitro. Interactions of these reactive oxygen species with particular cellular components and disruption of cell defense mechanisms still await further studies to elucidate the carcinogenic potential of asbestos fibers of different size and chemical composition. The distribution of inhaled pollutants and the magnitude of their eventual effects on the respiratory tract are determined by pollutant-independent physical factors such as anatomy of the respiratory tract and level and pattern of breathing, as well as by pollutant-specific phyco-chemical factors such as the reactivity, solubility, and diffusivity of the foreign gas in mucus, blood and tissue. Many of these individual factors determining dose can be quantified in vitro. However, mathematical models based on these factors should be validated for its integrity by using data from intact human lungs.

• Research in Community and Public Health Nursing
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• v.5 no.1
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• pp.64-80
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• 1994

The purpose of this study was to identify factors affecting family caregiver burden, and to identify the relationship between family caregiver burden and family function /self-care of psychiatric out-patient. These data were collected by questionnaire from September 20 to October 8, 1993. The subjects were 285 family caregiver of psychiatric out-patients. The instruments used in this study were Caregiver Burden Inventory(CBI) by Novak(1989), self-care performing by Yu(1992), and Family APGAR by Smilkstein(1979). The data were analyzed by cronbach's $\alpha$, mean, standard deviation, percentage, t-test, ANOVA, Pearson's correlation coefficient, and Stepwise Multiple Regression with SPSS /pc+ program. The result of this study were as follows ; 1. The means of family caregiver Burden revealed total 2.00, Time-Dependence Burden 78, developmental Burden 2.22, physical Burden 1.90, social Burden 1.43, emotional Burden 2.18, financial Burden 1.51. family caregiver burden score showed moderate level. time-dependence burden showed the highest score and social burden showed the lowest score. 2. The means of family function revealed total 5.67. 7 through high-21.4% (61), low through 3-38.6%(110). family function score showed moderate level. 3. The means of patient's self-care performance revealed total 137.71. self-care performance showed moderate level. 4. A ststistically significant correlation between family caregiver burden and patient's demographic variables, age (F=3.83, p<.01), marrital status(F=3.50, p<.01), job(F=3.17, p<.01), diagnosis(F=4.46, p<.01), income (F=4.46, p<.01). No significant differences between family caregiver burden and prevalent period, religion, sex (p>.05). S. A ststistically significant correlation between family caregiver burden and family's demographic variables, age (F=7.34, p<.01), sex(t=-2.63, p<.01), education level(F=7.61, p<.01), income (F=8.13, p<.01), relation with patient (F=6.92, p<.01), job(F=2.03, p<.05), medical service (F=3.89, p<.05), presence of chronically ill without patient(t=-2.01, p<.05) 6. Family function was the highest factor predicting family caregiver burden(R=.4168, $R^2=.1737$), low education level of family, patient's self-care, family income accounted for 36% in family caregiver burden.