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Marginal Adaptation of Zirconium Dioxide Core according to the Abutment Teeth (지대치 형태에 따른 지르코니아 코어의 변연 적합도)

  • Kim, Ki-Baek;Kim, Seok-Hwan;Kim, Jae-Hong
    • Journal of dental hygiene science
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    • v.15 no.1
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    • pp.54-59
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    • 2015
  • The present study investigated the influences of various abutment teeth shapes (maxillary right canine, pre-molar, molar) on the marginal adaptation of computer aided design/computer aided manufacturing-fabricated zirconia core. In vitro adaptation of zirconia cores manufactured by three different abutments were evaluated. Thirty zirconia cores were made per each models and the adaptation was evaluated through a silicone replica technique. The measurement of the adaptation was carried out using digital microscope. The mean and standard deviation of each reference point were analyzed using the one-way (ANOVA) and Tukey's honestly significant difference tests (${\alpha}=0.05$). The overall marginal fits of the zirconia cores were as follows: canine: $47.59{\mu}m$, pre-molar: $43.74{\mu}m$, molar: $40.36{\mu}m$. They were no statistically significant differences between groups for adaptation (p>0.05). This confirmed that the type of abutment teeth used does not determine the precision of fit of zirconia core.

Comparison of the Marginal and Internal Gap of Metal Coping according to Processing Method of Dental CAD/CAM System (치과 캐드캠 시스템의 가공 방식에 따른 금속 코핑의 적합도 비교)

  • Kim, Dong-Yeon;Jeon, Jin-Hun;Park, Jin-Young;Kim, Ji-Hwan;Kim, Hae-Young;Kim, Woong-Chul
    • Journal of dental hygiene science
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    • v.15 no.1
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    • pp.12-17
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    • 2015
  • The purpose of this study was to evaluate the marginal and internal gap of metal coping fabricated using additive manufacturing (AM) group and subtractive manufacturing (SM) group by dental computer-aided design (CAD)/computer-aided manufacturing (CAM) systems. Twenty same cases of stone models of abutment teeth 16 by the universal numbering system were manufactured and scanned. Ten metal copings of control group were fabricated using SM and ten metal coping of experimental group were fabricated using AM. Marginal and internal gap of copings were measured using the silicone replica technique and digital microscope (${\times}140$). The data were analyzed using IBM SPSS 21.0 Statistical Software for independent samples t-test (${\alpha}=0.05$). Mean${\pm}$ standard deviation (SD) of marginal and internal gap total size of SM group was $101.00{\pm}40.33{\mu}m$ of AM group was $83.61{\pm}40.37{\mu}m$. Mean${\pm}$SD of marginal and internal gap total size of SM group was significantly greater than that of AM group (p<0.05). This study showed that AM metal copings had a better marginal and internal gap than SM metal copings.

An Online Scaling Method for Improving the Availability of a Database Cluster (데이터베이스 클러스터의 가용성 향상을 위한 온라인 확장 기법)

  • Lee, Chung-Ho;Jang, Yong-Il;Bae, Hae-Yeong
    • The KIPS Transactions:PartD
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    • v.10D no.6
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    • pp.935-948
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    • 2003
  • An online scaling method adds new nodes to the shared-nothing database cluster and makes tables be reorganized while the system is running. The objective is to share the workload with many nodes and increase the capacity of cluster systems. The existing online scaling method, however, has two problems. One is the degradation of response time and transactions throughput due to the additional overheads of data transfer and replica's condidtency. The other is and inefficient recovery mechanism in which the overall scaling transaction is aborted by a fault. These problems deteriorate the availability of shared-nothing database cluster. To avoid the additional overheads throughout the scaling period, our scalingmethod consists of twophases : a parallel data transfer phase and a combination phase. The parallel data transferred datausing reduces the size of data transfer by dividing the data into the number of replicas. The combination phase combines the transferred datausing resources of spare nodes. Also, our method reduces the possibility of failure throughout the scaling period and improves the availability of the database cluster.

ESTIMATION OF RELATION BETWEEN TECHNIQUES OF DYE PENETRATION FOR MICROLEA-KAGE AND SEM EVALUATION FOR MARGINAL ADAPTATION OF THE RESTORATION (수복물의 미세누출도와 변연적합도 측정에 사용되는 방법 사이의 상관 관계 평가)

  • Hwang, Soon-Joo;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.31 no.5
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    • pp.337-343
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    • 2006
  • The purpose of this study was to estimate the relation between techniques used for microleakage from dye penetration and for marginal adaptation from SEM evaluation of the restoration. Using high speed #330 bur class V cavities ($4{\times}3{\times}1.5 mm$ around CEJ) were prepared on the buccal surface of 20 extracted human molars. Six dimples as reference points for SEM and dye penetration evaluation were made with 1/2 round bur. Cavity was bulk filled with microhybrid composite resin (Esthet X) and all-in-one adhesive (Xeno III). Teeth were stored in saline solution for one day, after then, they were finished and polished using Sof-Lex system. Fifty percent silver nitrate dye solution was used for the evaluation of microleakage and resin replica was used for marginal adaptation. All of these were done after 1000 times thermocycling between 5 and $55^{\circ}C$. Vertical sections were made through three dimples of restoration to obtain samples for the evaluation of dye penetration and inner marginal adaptation. Outer adaptational estimation was done with an intact restoration before sectioning. Dye penetration was determined in three degrees and percentage of outer and inner leaky margin was estimated from SEM image The data were analysed statistically: Spearman's rho test were used to check relationships between two methods. The result were as follows : 1. There were significant relationships between degree of dye penetration and inner and outer marginal adaptations each (p < 0.01). 2. However, there was no significant relationship between the results or inner and outer marginal adaptation. Within the results of this study, relationship between the percentage of marginal adaptation and microleakage shows significant relationship. However, inner and outer marginal adaptation did not show any significant relationship mutually.

Efficacy Evaluation of Anti-wrinkle Products in Japan

  • Masaki Hitoshi
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.29 no.2 s.43
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    • pp.67-77
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    • 2003
  • Two categories of cosmetic products, cosmetics and quasi-drugs, have been established by the Ministry of Health, Labor and Welfare (MHLW) in Japan. Japanese pharmaceutical law has defined that products categorized as cosmetics do not exhibit any effects on human skin. In fact, cosmetic products are not permitted to claim any efficacy. On the other hand, products in the quasi-drug category can claim several efficacies such as anti-inflammatory effects, whitening/lightning effects, hair growth effects and so on. Unfortunately, the Japanese MHLW has not yet approved the efficacy of anti-aging/anti-wrinkle effects as a claim point. However, the population is aging, and the demand for anti-aging/anti-wrinkle products is increasing year by year. Japanese cosmetic companies have proposed to the MHLW that anti-aging/anti-wrinkle agents be approved as a claim concept of a quasi-drug. However, unified evaluation methods for anti-aging/anti-wrinkle effects have not been established. Currently, each company evaluates the efficacy of products/materials using their own original methods. Thus, to request approval of the MHLW, the establishment of a unified evaluation method is needed. Consequently, the Japan Cosmetic Industry Association (JCIA) has established a task force to develop guidelines for evaluating anti-wrinkle effects in 1998. In conclusion, the JCIA would like to adopt visual and image analysis scales to evaluate the anti-wrinkle effects objectively. Generally, wrinkles are roughly classified into three groups as fine wrinkles, linear deep wrinkles and crow's feet. However, academic societies of dermatology or cosmetics have not yet established a definition of wrinkles in Japan. Thus, in advance of setting up an evaluation method, the definition of wrinkles f3r evaluation must be decided. Wrinkles are defined by the task force of the JCIA as follows; furrows that people can recognize visually and that appear on the forehead, the corners of the eyes and the backs of the neck with aging. In addition, furrows are emphasized by exposure to solar light and by dry conditions. Visual evaluation is the most sensitive method and can be applied to most types of wrinkles. However, visual evaluation is hard to express digitally as results. Besides, in the case of image analysis, comparisons of data obtained from distinct examinations can not be done, because data from image analysis are relative values. Thus, to enhance the reliability of the evaluations, the adoption of an objective scale was required. The principle of the evaluation method is to analyze images taken from silicone replicas of wrinkle areas using several parameters, such as the proportion of the wrinkle $area({\%})$, the mean depth of the wrinkles (mm), the mean depth of the deepest wrinkle (m) and the deepest point on the deepest wrinkle. Lights are shown on the skin replica from an orthogonal direction of the main orientation of the wrinkle, and the resulting shadow images are quantified by the image analysis method. To increase the precision of the data or to allow comparisons of independent examinations, a scale with furrows of several depths, 200, 400, 600, 800, and $1000{\mu}m$, is adapted in the evaluation system. I will explain the guidelines established by the JCIA in the presentation.

A Case Study of Parenting Education Program for Students with School-Maladjustment (학교부적응 학생 대상 예비부모교육 수업 적용 사례 연구)

  • Oh, EunYoung;Choi, Saeeun
    • Journal of Korean Home Economics Education Association
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    • v.31 no.3
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    • pp.117-134
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    • 2019
  • This study aims to explore the effects of the parenting education program for high-school maladjusted students. To this purpose, a parenting education program for adolescents developed by the Ministry of Gender Equality and Family(MOGEF) was applied to ten high-school maladjusted students in an alternative(Dae-an) class in Jeju. Findings from class observations and interviews with participants are as follows. First, students with school maladjustment recognized importance and necessity of positive self-concepts and had an opportunity for self-growth through parenting education program. Second, students with school maladjustment obtained understanding about their family of origin and confidence for forming their future families. Third, advance learning about meanings and roles of being a parent provided students with opportunities to know importance of responsible sexual behavior. Fourth, practices of basic care with a replica of a new-born baby enhanced participation and concentration level of students with school maladjustment which became extremely effective in obtaining necessary knowledge for the basic care. Fifth, information provision for parent roles according to children's different developmental levels let students recognize that parent's roles change as their children grow and opened a way to grasp the need of parent education. Sixth, education and repetitive practices on reflective listening helped students enhance communication skills which entailed expanding their human relations. Seventh, passing-down of emotion and understanding on child abuse allowed students recognize risks of child abuse as well as the importance and need of skills for controlling emotion. This study sheds lights on the feasibility and effectiveness of a parenting education program for maladjusted or vulnerable students as an effective program for school drop-out prevention.

Synthesis of ZSM-5 on the Surface of Foam Type Porous SiC Support (폼 형태의 다공성 탄화규소 지지체 표면 위에 ZSM-5 합성)

  • Jung, Eunjin;Lee, Yoon Joo;Won, Ji Yeon;Kim, Younghee;Kim, Soo Ryong;Shin, Dong-Geun;Lee, Hyun Jae;Kwon, Woo Teck
    • Korean Chemical Engineering Research
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    • v.53 no.4
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    • pp.425-430
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    • 2015
  • ZSM-5 crystals grew by hydrothermal synthesis method on the surface of foam type porous silicon carbide ceramics which fabricated by polymer replica method. Oxide layer was developed on the surface of the porous silicon carbide ceramics to induce growth of ZSM-5 from the surface. In this study, hydrothermal synthesis was carried out for 7 h at $150^{\circ}C$ using TEOS, $Al(NO_3){\cdot}9H_2O$ and TPAOH as raw materials in the presence of the porous silicon carbide ceramics. X-ray Powder Diffraction (XRD) and Scanning Electron Microscope (SEM) analyses were confirmed $1{\sim}3{\mu}m$ sized ZSM-5 crystals have grown on the surface of porous silicon carbide ceramics. BET data shows that small pores about $10{\AA}$ size drastically enhanced and surface area increased from $0.83m^2/g$ to $30.75m^2/g$ after ZSM-5 synthesis on the surface of foam type porous silicon carbide ceramics.

UVB-INDUCED CHANGES OF BARRIERFUNCTION AND MORPHOLOGY OF THE HAIRLESS MOUSE SKIN (자외선-B에의한 Hairless mouse의 보호기능과 표면구조의 변화 영향)

  • Kim, Jin-Jun;Park, Mun-Eok;Gang, Se-Hun
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.18 no.1
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    • pp.81-98
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    • 1992
  • Hairless mice (Skh:HR-1) exposed to single doses (0.5, 1.0 and 3. OMED) of UV-B radiation were displayed remarkable changes of barrier function and surface morphology. Trans- epidermal water loss (TEWL) as an index of barrier function was measured by evaporimeter, and wrinkle density (WD) as an index of morphological alteration was measured by image analyzer. Significant changes of TEWL were not observed in the control and 0. SMED group, but 1.OMED and 3. OMED groups noted significant difference. TEWL of 3. OMED group was rapidly increased to the 3rd day and decreased until the 14th day when it reached nearly to normal level, Time-courses of TBWL for 1. OMEB and 3. OMED groups displayed similar pattern, but different only in the magnitude. WD were significantly decreased during the 3rd-5th day in all of the irradiated groups and then increased during the last period to the 14th day, but did not recover the normal level at the 14th day. Time-courses of WD for all groups exhibited similarity, and were entirely dependent on the exposed doses. We also observed histological changes which included hyperplasia, sunburn cell (SBC) formation, accumulation of polymorphonuclear leukocyte (PMNs), and loss of collagen of UVB- exposed hairless mouse skin. Changes of TEWL and WD are helpful in understanding of epidermal and dermal damages by single exposure of UVB.

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The Study on the Potential Anti-aging Properties of Prunella vulgaris Extract In Vitro and In Vivo (하고초 추출물의 항노화 효과에 관한 연구)

  • Hong, Eun-Suk;Ahn, Gi-Woong;Jo, Byoung-Kee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.34 no.2
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    • pp.129-135
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    • 2008
  • In this study, the potential anti-aging properties of Prunella vulgaris extract were investigated. According to our results, Prunella vulgaris extract increased collagen synthesis(74.7% at 250 ${\mu}g/mL$) and decreased on MMP-1 synthesis(90.2% at 200 ${\mu}g/mL$) and elastase activity(43.7% at 2.0%). Furthermore, it also showed free radical scavenging activity(76.9% at 2.0%) and reduced $H_2O_2$-induced cytoxicity(49.9% at 2.0%). A double-blind clinical study to investigate the effect of Prunella vulgaris extract on the skin's surface was conducted with 22 healthy volunteers, aged 34 to 48 years. The volunteers applied a cream formula with 4.0% of Prunella vulgaris extract, or placebo cream, on each crow's feet twice a day for 12 weeks. Skin wrinkles were evaluated with the naked eye and instrumental image analysis of silicone replicas, followed by statistical analysis. Twelve weeks after application of cream formula with 4.0% of Prunella vulgaris extract, we found significant improvement of facial wrinkle. Moreover, silicone replica analysis confirmed notable improvement in average of R2 and R3 at 12 weeks(p<0.05). These results demonstrate that Prunella vulgaris provides a remarkable and significant tensor and anti-wrinkle effect on the skin, which could be of great use in anti-aging skin care products.

Effect of Porcelain Firing Process on the Marginal and Internal Fit of Ni-Cr Alloy Metal-Ceramic Crown (도재 소성과정이 Ni-Cr 금속도재관의 변연 및 내면 적합도에 미치는 영향)

  • Kim, Ki-Baek;Kim, Seok-Hwan;Kim, Jae-Hong
    • Journal of dental hygiene science
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    • v.14 no.3
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    • pp.405-410
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    • 2014
  • The purpose of this study in vitro investigation was to compare the marginal and internal fit of Ni-Cr alloy metal ceramic crown before and after porcelain veneering. Furthermore, this study evaluated whether the influence of the porcelain firing on the precision of fit of dental prostheses. The maxillary right incisor was selected as an abutment for experiments. Ten working models were prepared. Ni-Cr alloy cores appropriate for each abutment were prepared by lost wax technique. The marginal area and four internal areas of the crowns were measured at two stages: before veneering process and after upper porcelain firing. Silicone replica techniques were used. The data were statistically analyzed with the paired t-test (${\alpha}=0.05$). $Mean{\pm}SD$ marginal and internal gap were $67.1{\pm}23.3{\mu}m$ for the nickle chrome alloy core group and $74.4{\pm}21.9{\mu}m$ for the metal ceramic crown group. There were statistically significant differences in all investigated areas (p<0.05). Within the limitations of this study, none of the Ni-Cr alloy metal crown values measured after porcelain firing process exceeded $120{\mu}m$, which is the clinically acceptable threshold.