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A STUDY ON THE CORROSION BEHAVIOUR OF AMALGAMS BY USING OF POTENTIOSTATIC POLARIZATION METHOD (정전압 분극곡선법에 의한 아말감의 부식 거동에 관한 연구)

  • Shin, Dong-Hoon;Um, Chung-Moon
    • Restorative Dentistry and Endodontics
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    • v.12 no.1
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    • pp.39-49
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    • 1986
  • The purpose of this study was to observe characteristic properties through the polarization curves and SEM images from 4 different types of amalgam obtained by using the potentiostats (Princeton EG & G) & SEM (Jeol/35), and to investigate the degree of corrosion on the oxidation peak of the each phase of amalgam. After each amalgam alloy and Hg was triturated as the direction of the manufacturer by means of the mechanical amalgamator (Shofu Co.), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10.0mm in height and was condensed by using routine manner. The specimen was removed from the mold and stored at room temperature for about 24 hours. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to confirm the corrosion behaviour of the amalgams in a 0.9% saline solution (P.H: 6.8-7.0) at $37^{\circ}C$. The initial rest potential (corrosion potential) was determined after 30 minutes of immersion of specimen in electrolyte, and the potential scan was begun at the point of 100mV cathodic from the corrosion potential. The scan rate was 0.17mV/sec. in the study to observe the degree of corrosion of each phase. SEI and EPMA images on the determined oxidation peaks of each amalgam were observed. The results were as follows: 1. In the four anodic polarization curves, low copper amalgams have three oxidation peaks and high copper amalgams have two oxidation peaks, -270mV, +26mV and +179mV(SEC) in the low copper lathe cut, and -300mV, +39mV and +163mV(SEC) in the low copper spherical. -4mV and +154mV(SEC) in the Dispersalloy, and +17mV and +180mV(SEC) in the Tytin as high copper amalgams. 2. ${\gamma}_2$ phase in the low copper amalgam and ${\eta}$ phase in the high copper amalgam were the most corrodible phases and Ag-Cu eutectic in high copper amalgam was the most slowly corroded phase. 3. Low copper amalgam was more susceptible in corrosion than high copper amalgam.

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COMPARISON OF COMMUNICATION AND MOTHER-CHILD INTERACTION PATTERNS BETWEEN REACTIVE ATTACHMENT DISORDERED CHILDREN AND NORMAL CHILDREN (반응성 애착 장애아(反應性 愛着 障碍兒)와 정상아의 의사소통 및 모자 상호작용 유형 비교연구)

  • Lee, He-Len;Choi, Young-Rim
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.5 no.1
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    • pp.118-132
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    • 1994
  • The purpose of this study was to compare communication and mother-child interactions of reactive attachment disordered children with normal children. The subjects were 24 children and their mothers participated in this study'12 reactive attachment disordered children and mothers, 12 normal children and mothers. The mother and her child were brought into a p]lay room and the mother was instructed to play with her child as she normally would at home. The play situations were videotaped. Tapes were transcribed and transcribed data was analyzed with 13 mutually exclusive categories encompassing pragmatic functions represented in communication form the early stage of multiword speech in childhood. The tapes were analyzed with 10 behavioral mother-child interaction patterns. As the statistical method, t-test and correlation was calculated. The results of this study were as follows : 1) Reactive attachment disordered children used significantly fewer 'filler', 'information', 'requests', 'describes' and 'disscus self'. 2) Reactive attachment disordered children's mother used significantly fewer 'filler' and 'names'. 3) Reactive attachment disordered children used significantly more 'independent play', fewer 'intiates interaction', 'responsiveness' and 'answer' Reactive attachment disordered children's mother used more 'control play', 'observe' and fewer 'initiates interaction'. 4) Children's communication patterns were related lo mother·'s communication and mother-child interaction types. Children's 'filler', 'information requests', 'describes' and 'disscus self' were consistantly related to mother's 'filler' and 'names', (Children's 'filler', 'information requests', 'describes'. 'disscus self' and mother-child's intiates interaction 'responsivness' were significantly positively correlationed and 'independant play', 'control play', 'observation' were significantly negatively correlationed. The results of reveal that communication and mother-child interaction pattern of reactive attachment disordered group was different from normal group and children's communication pattern were influenced by mother's communication and interaction patterns.

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AN EFFECT OF HYALURONIC ACID ON THE TEMPOROMANDIBULAR JOINT ARTHROCENTESIS (악관절강내 천자술시 히알루산(Hyaluronic acid) 사용에 대한 임상적 연구)

  • Yeo, Hwan-Ho;Kwon, Byong-Gon;Kim, Jae-Seung
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.21 no.4
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    • pp.388-394
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    • 1999
  • To compare the effect of hyaluronate and dexamethasone on the temporomandibular joint arthrocentesis the author investigated 22 temporomandibular joint disorder(TMD) patients with pain and limitation of mouth opening who visited at the Department of Oral and Maxillofacial Surgery. Chosun Dental Hospital and were made a diagnosis as Wilkes stage III or IV of TMJ internal derangement clinically and radiographically. The two groups consisted of 10 patients with injection of sodium hyaluronate 10mg$(Artz^{(R)})$(hyaluronate group) on the upper joint space of the affected temporomandibular joint 5 times at intervals of a week after arthrocentesis, and 12 patients with injection of dexamethasone$(Oradexon^{(R)})$ at a time(dexamethasone group). Maximum mouth opening, pain value and satisfaction value during mastication were assessed on a visual analog scale before arthrocentesis and after 6 months. Then the within-group and between-group differences were evaluated in the obtained data and the clinical success rate of each group was calculated according to our success criteria. The results were as follows. 1. the mean of maximum mouth opening before arthrocentesis and after 6 months in the hyaluronate group were 24.9mm and 39.0mm respectively, and those before arthrocentesis and after 6 months in the dexamethasone group were 25.7mm and 41.3mm respectively. 2. The mean of pain value on a visual analog scale in the hyaluronate group before arthrocentesis and after 6 months were 6.7 and 1.8 respectively, and those in the dexamethasone group before arthrocentesis and after 6 months were 7.0 and 1.8 respectively. 3. The mean of satisfaction value during mastication on a visual analog scale in the hyaluronate group before arthrocentesis and after 6 months were 2.8 and 7.7 respectively, and those in the dexamethasone group before arthrocentesis and after 6 months were 3.1 and 7.8 respectively. 4. There were statistically significant differences between all measurements before arthrocentesis and after 6 months(P<0.001), but no difference between all measurements in the hyaluronate group and those in the dexamethasone group. 5. The over all success rate of the hyaluronate group and the dexamethasone group were 60.0% and 63.6% respectively. In summary, there was significant difference between the effect of hyaluronate and dexamethasone on the temporomandibular joint arthrocentesis but hyaluronate is better than corticosteroid as the injection drug in consideration of the side effect related with repeated injection.

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The Effects of Static Magnetic Field and Pulsed Electromagnetic Field on Alkaline Phosphatase and DNA synthetic Activity of ME3T3-E1 Cells (정자기장과 맥동전자기장이 MC3T3-E1 세포의 ALP 및 DNA 활성도에 미치는 영향)

  • Son, Jeong-Hee;Bae, Seong-Min;Sung, Jae-Hyun
    • The korean journal of orthodontics
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    • v.27 no.4 s.63
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    • pp.623-632
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    • 1997
  • The purpose of this study was to evaluate the effects of magnetic field on cellular activity of MC3T3-E1 cells. The cellular activity was monitored by alkaline phosphatase and DNA synthetic activity in control, static magnetic field and pulsed electromagnetic field groups. A static magnetic field was applied to the cell by placing one, two, three, foue, and five samarium-cobalt magnets above and below each cell plate for 24hours per day. A pulsed electromagnetic field with a frequency of 100 herz was applied for 10 hours per day. After 10 days of magnetic field exposure, there were increase of alkaline phosphatase activity in static magnetic field groups consisted of one, two and three magnetic groups. Alkaline phosphatase activities were not significantly increased in four and five magnetic groups. Application of pulsed electromagnetic field did not result in significant increase in alkaline phosphatase activity compared to control. DNA synthetic activity in both static and pulsed electromagnetic field group were not significantly different from that in control group. The result of this study suggest that magnetic field could have effect on the metabolism of bone cells related to the cellular metabolic process.

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A Study on Health Belief and Health Behaviors of the Elderly (노인의 건강신념과 건강관행에 관한 연구)

  • Wang, Myoung-Ja;Cha, Nam-Hyun
    • Journal of East-West Nursing Research
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    • v.8 no.1
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    • pp.103-112
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    • 2003
  • This paper focused on providing the groundwork for the development of proper nursing interventions to enhance the quality of life for the elderly by identifying the factors that may affect their health beliefs and behaviors. A survey was conducted on a group of people aged between 60 and 86 years residing in S and K cities from January to March of 2003, who agreed to participate in the research. Data was collected using instruments measuring health beliefs and health behaviors, and was analyzed by using SPSS. The results of this study are as follow. 1) Those in the group were aged between60 and 86 years, and the average age was 66.94 years old. Most of them were living together with their spouses. From the survey, 83.5% replied "above average" on the question regarding their current health condition, whereas, 46.0% mentioned that they had some sort of diseases. 2) Overall average score of the health belief was 516.05, with a mean $3.71{\pm}4.07$. This indicates that the studied group held a high level of health belief, which affects their attitude and intention to lead a healthy life by placing the present life under control in harmony with nature. 3) Overall average score of the health behaviors was 392.24 with a mean $2.82{\pm}.52$. For health purposes, the behaviors that the elderly people were taking were mostly static ones requiring a low level of activity. The analysis showed that they generally were involved in self-trained, individualized health care. Thus, the elderly place a higher priority on regular dietary behaviors than on physical activity. 4) The correlation between health belief, a cognitive aspect on health, and health behaviors, a behavioral aspect showed a very high linear relationship (r=.520, p<.000). Consequently, it is found that those who have higher cognitive health belief are involved in higher level of behavioral health practice. These findings concluded that the Korean elderly have good health beliefs, well controlling their minds and being harmonious with nature. Health behaviors that they are engaged in are mostly static, requiring low level activity, while they place higher priority on regular dietary habits and conducting self-trained individualized health care. Important factor affecting their health beliefs and health behaviors was found to be their health practice. Since higher health belief is highly related with good health behaviors, development of health activity programs is in need as a means for an efficient health improvement, where motivating environment may be established to enhance the health belief of the elderly and to satisfy individual values.

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Effect of Gentro $F^{(R)}$ on Abdomen Fat (젠트로 $F^{(R)}$의 복부지방에 미치는 영향)

  • Lee, Gye-Won;Lee, Joo-Yeon;Yu, Byong-Yeon;Byun, Mu-Won
    • YAKHAK HOEJI
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    • v.51 no.6
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    • pp.455-462
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    • 2007
  • The participants were recruited 77 healthy adult persons aged between 20 and 50 who have BMI above $25kg/m^2$ in this study. All subjects were randomly assigned to the Gentro $F^{(R)}$ drinking group and non-drinking group. We were investigated about abdomen fat decreasing effect of Gentro $F^{(R)}$, distillate of pepper. Total fat area (TFA), subcutaeneous fat area (SFA) and visceral fat area (VFA) and subcutaneous fat area/visceral fat area ratio (SVR) has been assessed by obesity index (BMI, body fat percent, waist circumference), CT scan taken on the $L4{\sim}5$ position, umbilicus level and blood analysis evaluated during 3 month. The obesity indexes were a little decreased in two groups. However, the waist circumference (WC) was decreased about 5% in drinking group after 3 month and there was significant difference in the change 2 and 3 between two group. TFA and VFA were significantly decreased in the drinking group compare to the non-drinking group (p<0.05) and in umbilicus and $L4{\sim}5$ position, were $370.33{\pm}92.30,\;380.35{\pm}97.64\;and\;114.90{\pm}44.91,\;101.99{\pm}41.24$, respectively. These result means that Gentro $F^{(R)}$ is effective on abdomen fat decreasing. Total cholesterol were decreased without difference in both groups. Lipid factors (TG, HDL- and LDL-cholesterol) were decreased without significance. The mea surement of SVR taken on the $L4{\sim}5$ position were more significantly correlated with obesity index that BMI was 0.787, body fat percentage was 0.754 than on the umbilicus level. The TFA and VSA was correlated with ALP, ASP, Albumin, Insulin and the SVR was correlated with the indexes of liver function and lipid factor found in the blood. Therefore, it is conclude that Gentro $F^{(R)}$ drinking leads to a decrease in abdominal obesity by reducing waist circumference and visceral fat area.

Anamnestic Skin Reactivity upon Repeated Tuberculin Tests in the BCG Vaccinated or Unvaccinated Primary School Children (투베르쿨린 반부검사(反復檢査)에 의한 회상반응(回想反應)에 관한 연구(硏究))

  • Kim, S.J.;Hong, Y.P.;Chang, S.C.;Kang, M.K.
    • Tuberculosis and Respiratory Diseases
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    • v.38 no.1
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    • pp.34-44
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    • 1991
  • Restoration of skin reactivity to 1 TU of tuberculin (RT23) by repeated tests at 10 days interval has been investigated in the BCG vaccinated or unvaccinated primary school children. The results obtained are as follows. 1) Tuberculin reactors showing 6 mm or larger induration to the first tests were 20.0% in the first grade school children and 33.3% in the sixth grade children. Six millimeter or larger reaction than that of the first reaction was found in 14.9% of the first grade children and in 34.6% of the sixth grade children. 2) Six millimeter or larger reactors were 10.8% of the first grade children without BCG scar against both first and second tests and 11.8% of the sixth grade children on first tests and 10.6% on second tests. There was none or very few, if any, in number of 6 mm or larger difference between the first and second tests among children without BCG scar. In addition, there was no children shown 6 mm or larger second reaction than that of the first reaction and thus those reactors seemed to be natural infection. 3) From questionaire survey, parents of 73.3% of the first grade children and of 72.7% of the sixth grade children were aware of BCG vaccination of their children, while parents of 15.1% and 24.6% of the first and sixth grade children did not know their children's vaccination history even if children possessed BCG scar. 4) Of the first grade children whose parents remembered their BCG vaccination, 65.6% were vaccinated within 4 weeks after birth and 25.5% between 4 weeks and one year. Six millimeter or larger reaction on the first tests was observed in 20.2% of the former group and 15.9% of the latter group, however reactors on the second tests were 32.1% and 31.9% respectively. BCG scar was not observed in 13.9% of children. 5) The majority of children (87.3%) were vaccinated in the skin of deltoid area and some (7.7%) at buttock or other areas. Children received first vaccination at the health centers were 68.5% and 30.3% at hospitals. More than 5 mm reaction was found in 18.7% of the former children and in 15.0% of the latter children. From this study restoration of tuberculin reactivity by repeated tests was found very common among the vaccinated children and thus it should be taken into account for the vaccination policy if it is performed after tuberculin testing.

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Effect of Alkali and Heat Treatments of Ti-6Al-4V Alloy on the Precipitation of Calcium Phosphate (Ti-6Al-4V 합금의 알칼리 및 열처리가 인산칼슘 침착에 미치는 영향)

  • Park, Jae-Han;Lim, Ki-Jung;Kim, Sang-Mok;Kim, Byung-Ock;Han, Kyung-Yoon
    • Journal of Periodontal and Implant Science
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    • v.30 no.1
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    • pp.187-203
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    • 2000
  • The precipitation of calcium phosphate on implant surface has been known to accelerate osseointegration and to enhance osseous adaptation. The present study was performed to examine whether the precipitation of calcium phosphate on Ti-6Al-4V alloy could be affected by the immersion in NaOH solution and heat treatment. Ti-6Al-4V alloy plates of $15{\times}3.5{\times}1mm$ in dimension were polished sequentially from #240 to #2,000 emery paper and one surface of each specimen was additionally polished with $0.1{\mu}m$ alumina paste. Polished specimens were soaked in various concentrations of NaOH solution(0.1, 1.0, 3.0, 5.0, 7.0, 10.0 M) at $60^{\circ}C$ for 24 hours for alkali treatment, and 5.0 M NaOH treated specimens were heated for 1 hour at each temperature of 400, 500, 600, 700, $800^{\circ}C$. After the alkali and heat treatments, specimens were soaked in the Hank's solution with pH 7.4 at $36.5^{\circ}C$ for 30days.The surface ingredient change of Ti-6Al-4V alloy was evaluated by thin-film X-ray diffractometer(TF-XRD) and the surface microstructure was observed by scanning electron microscope(SEM), and the elements of surface were analyzed by X-ray photoelectron spectroscopy(XPS). The results were obtained as follows ; 1. The precipitation of calcium phosphate on Ti-6Al-4V alloy was accelerated by the immersion in NaOH solution and heat treatment. 2. In Alkali treatment for the precipitation of calcium phosphate on Ti-6Al-4V alloy, the optimal concentration of NaOH solution was 5.0 M. 3. In heat treatment after alkali treatment in 5.0 M NaOH solution, the crystal formation on alloy surface was enhanced by increasing temperature. In heat treated alloys at $600^{\circ}C$, latticed structure and prominences of calcium phosphate layer were most dense. On heat treated alloy surface at the higher temperature(${\geq}700^{\circ}C$), main crystal form was titanium oxide rather than apatite. The above results suggested that the precipitation of calcium phosphate on the surface of Ti-6Al-4V alloy could be induced by alkali treatment in 5.0 M-NaOH solution and by heat treatment at $600^{\circ}C$.

The Plant Resources of the Sand Dune on Southern Coast and Jeju Island, Korea (남해안 및 제주도 일대 해안사구의 자원식물상)

  • Oh, Seung-Hwan;Kim, Hyuk-Jin
    • Korean Journal of Plant Resources
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    • v.21 no.5
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    • pp.374-387
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    • 2008
  • This study was carried out to investigate the distribution of the useful resources plants and the flora of the sand dune on South Coast and Jeju Island. The flora of sand dune on South Coast and Jeju Island was investigated from February to November in 2006. Vascular plants of this area consist of total 171 taxa; 1 forma, 18 varieties, 152 species, 130 genera, 51 families. The dominant species in the vegetations of the south coast sand dune were Calystegia soldanella, Ischaemum anthephoroides, Vitex rotundifolia, Carex pumila, Carex kobomugi. It corresponds to 11.1 % of totally 4,071 taxa appeared in Korea. Useful plants of this area were investigated 113 taxa. It corresponds to 66% of collected plants in this area under our study. Among the useful plants, there are 73 taxa of edible source, 61 taxa of medicinal source, 22 taxa of pasture source, 16 taxa of ornamental source, 7 taxa of fiber source, 1 taxa of timber source. Korean endemic plants were composed 1 taxa.

Stability of Vitamin-C Inclusion Comolexes Prepared using a Solvent Evaporation Method (용매증발법으로 제조된 Vitamin-C 포접복합체의 안정성)

  • Yang, Jun-Mo;Lee, Yun-Kyung;Kim, Eun-Mi;Jung, In-Il;Ryu, Jong-Hoon;Lim, Gio-Bin
    • KSBB Journal
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    • v.21 no.2
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    • pp.151-156
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    • 2006
  • Vitamin-C is one of the typical bioactive substances widely used in the cosmetic and pharmaceutical applications. It is well known that the bioavailability of vitamin-C decreases with time because it is spontaneously oxidized in the presence of oxygen. In this study, vitamin-C inclusion complexes were prepared by formulating vitamin-C with 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) to protect vitamin-C from being oxidized. Vitamin-C inclusion complexes were prepared by a solvent evaporation method using a rotary evaporator and various solvents of different dielectric constant such as ethanol, methanol and distilled deionized water to investigate the effect of solvent polarity on the stability of vitamin-C. To estimate the stability of inclusion complexes, samples were stored in a 50 mM phosphate buffer solution of pH 7.0 for 24 hours at $25{\pm}0.1^{\circ}C$ and the degradation rate of vitamin-C was calculated using a high performance liquid chromatography. The stability of vitamin-C was observed to improve with the increase of solvent polarity.