• Journal of dental hygiene science
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• v.10 no.4
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• pp.295-300
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• 2010

The aim of this study were to elucidate effects of fluoridated bleaching agents and post-treatment fluoride application on the color and microhardness of enamel surface. Twenty freshly extracted human adult molar were each sectioned into halves, the specimens divided and treated according to four experimental groups: 1, untreated controls: 2, treatment with 10% carbamide peroxide (CP) bleaching agent; 3, treatment with 10% CP containing 0.11% fluoride; 4, treatment with 10% CP followed by a 0.9% sodium fluoride gel application. Group 2-4 were compared with the baseline data. treated 8 h per day for 14 days then immersed in distilled water for 2 weeks. Changes in enamel color and microhardness were evaluated on Days 7 and 14. All the bleached enamel specimens revealed increased whiteness and overall color value. Groups 2 and 4 showed significantly decreased enamel microhardness compared to their baseline. The specimens treated with fluoridated bleaching agents showed relatively less reduction in enamel microhardness than those treated with nonfluoridated agents during the bleaching treatment. The addition of fluoride did not impede the tooth whitening. The fluoridated bleaching agents reduced the microhardness loss of enamel.

• The Korean Journal of Ecology
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• v.24 no.3
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• pp.157-168
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• 2001

Herbicides have been used to control weeds for decades. If detoxification upon exposure to herbicides requires considerable amounts of energy, it could affect the pattern of resource allocation to growth and reproduction of crops. We examined the effects of three levels of a herbicide (Control, Low, and High) on germination, growth and reproductive characters of Glycine max treated twice, i.e., before and after seed germination. Since flowering time of G. max was separated into two groups, flowering time was also considered as a variable in this study. The rate of seed germination tended to be higher at the low level of herbicide compared to other levels. Chlorosis and shape variation of leaves were apparent after the second herbicide treatment, but completely disappeared after six weeks of treatment. The herbicide effects on growth characters were somewhat different between early and late flowering plants, but plants treated with both low and high levels of herbicide reduced their growth compared to those in the control group regardless of flowering time. Plants at the high level of herbicide exhibited the highest growth rate later in the season, suggesting that plants compensated to some extent for reduced growth. However, growth reduction among plants at the high level of herbicide was persistent until the end of growing season. Among plants flowered late in the season, plants in the control level bore a higher number of nodules per plant than those in other levels; such a pattern did not exist among plants flowered early in the season. Plants treated with low and high levels of herbicide produced a lower number of flowers than those in the control. Thus, the herbicide examined affected not only the growth and reproductive characters of non-target crops but also the development and growth of root nodules.

• Korean Journal of Psychosomatic Medicine
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• v.30 no.2
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• pp.155-164
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• 2022

Objectives : A growing body of evidence links type 2 diabetes (T2D) with a neurodegenerative disease (ND) such as Alzheimer's disease and Parkinson's disease. The purpose of this study is to investigate the relationship between NDs and the development of T2D by comparing the incidence of T2D in a group of various NDs (ND group) and control group. Methods : A population-based 10-year follow-up study was conducted using the Korean National Health Information Database for 2002-2015. We used a retrospective cohort study design to investigate the association of ND with T2D occurrence. The study population included ND (n=8,814) and control (n=37,970) groups, all aged 60 years or over. The Kaplan-Meier method was used to estimate the risk of developing T2D as a function of time. Cox proportional hazards regression models were used to evaluate the relationship between ND and T2D. Results : T2D was developed in a significantly higher percentage of patients in the ND group (53.6%) than in the control group (44.7%). The ND group increased the risk of T2D (HR, 1.43; 95% CI, 1.38-1.47). About one-third of patients in both groups were additionally diagnosed with another ND before the occurrence of T2D during a 10-year follow-up period. When compared to those who did not have another ND during the follow-up period, the incidence of T2D in those who were additionally diagnosed with another ND was higher in both the ND and control groups. Conclusions : The ND group had about 1.4 times higher risk of developing T2D than the control group. Our results showed a positive association between ND and T2D.

• The Monthly Technology and Standards
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• s.101
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• pp.26-27
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• 2010

유해물질제한지침(RoHS)의 제6조항에 따라 유럽위원회가 지침을 재검토 중이다. 유럽의회는 RoHS 규제에 현 8종의 전기전자 제품군에서 모든 제품으로의 규제 시행 확대와 기존 4종의 중금속과 2종의 난연제 규제에서 브롬계 난연제, 크롬계 난연제, PVC, 유해 플라스틱 첨가제 등의 즉각적 규제를 목표로 하고 있다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.1
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• pp.10-19
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• 1992

서해안 시대를 맞이하여 21세기를 열어나갈 새萬金 千拓綜合開發事業 기공식이 지난해 11월 28일 전북 부안군 변산면 대항리 현장에서 盧泰愚대통령, 曺京植농림수산부장관, 金榮鎭農漁村振興公私社長, 국회농림수산위원회 위원장, 전북도지사, 地域出身國會議員등 내외 귀빈과 지역 주민 2,400여명이 참석한 가운데 열려 사상 최대의 간척사업으로서 첫발을 내딛었다. 이날 盧泰愚대통령은 치사를 통해 "자손만대에 물려줄 웅대한 국토확장의 첫삽을 뜨게 되어 깊은 감회를 느낀다"면서 "만경, 김제의 넓은 벌이 우리나라의 곡창으로 겨레의 삶을 보장해온 터전이었듯이 새만금의 광활한 간척지를 21세기 번영을 기약하는 땅이 되도록 하자"고 당부하였다. 새만금사업의 공사기간은 '91년부터 98년까지 외곽방조제를 완공하고 2004년까지 내부개발을 완료할 예정이고, 총 사업비 1조 3천억원을 투입하게된다. 사업지역은 1도 3군 1시 19읍면동 (전북 옥구군, 부안군, 김제군, 군산시)에 걸쳐서 40,100ha를 개발하게 된다. 주요시설로는 부안군 변산면 대항리에서 可力島, 新侍島, 夜味島, 및 飛鷹島를 연결하는 세계 최장의 방조제 33km를 축조하고 방조제 위에는 4차선 도로를 설치하고 장항선이 군산하구둑을 경유, 이 방조제를 거쳐 고군산군도까지 갈 수 있도록 하는 철도부지도 건설된다. 이와 함께 새만금국제항을 개설, 연간 5,000만톤의 하역능력을 갖게 되고 고군산군도를 잇는 관광휴양지가 형성된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.255-261
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• 2002

The purpose of this study was to compare the microleakage pattern of flowable composite resin to sealant, composite resin used in preventive resin restoration and glass ionomer cement used as liner. 120 extracted sound human molars were divided into 6 groups : group 1 and 2:sealant ; group 3 and 4:preventive resin restoration ; group 5 and 6:sandwich technique restoration. For the experimental groups(group 2, 4 and 6), flowable composite resin(Tetric flow) was used. For the control group, Concise was used as sealant material(group 1), Z-100 with Concise were used as preventive resin restoration(group 3), and Vitrebond was used as cavity liner(group 5). All the restorations were thermocycled and the degree of dye penetration was evaluated with stereomicroscope. The microleakage of each group was measured and statistically analyzed. The results of the present study were as follows : 1. In group 1 and 2, there was no statistically significant difference in microleakage between Concise and Tetric flow(p>0.05). 2. In groups of preventive resin restorations, there was no statistically significant difference in microleakage between Z-100 with Concise and Tetric flow(p>0.05). 3. The microleakage of Vitrebond and Tetric flow used as liner showed no statistically significant difference(p>0.05).

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.546-559
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• 1997

The purposes of this study were to evaluate the efficiency of cavity preparation and to determine the incidence of tooth crack when root-end retrograde cavity preparation was done with ultrasonics. 91 distobuccal root-ends of extracted human maxillary first molars were cut by 3 mm perpendicularly to the long axis of tooth using a slow speed diamond saw, retrocavities were prepared using a slow-speed no. 2 round bur as controls, and stainless steel ultrasonic tips of power settings of 1 through 10 as experimentals. Time consumed and the number of strokes used for the cavity preparation were measured and evaluated, and the incidence of tooth cracks was observed under a stereomicroscope. The results were as follows : For the retrograde cavity preparation, time and number of strokes used were decreased as the ultrasonic power setting increased (p<0.001). High power setting of ultrasonics induced significantly more tooth cracks than did the slow-speed bur or low- and medium power setting of ultrasonics (p<0.05). Teeth with previous crack induced significantly more tooth cracks than those without previous one when high power setting of ultrasonics were used for the retrograde cavity preparation (p<0.001). Teeth with initial apical canal size of no. 10 induced significantly more crack than did those with size of no. 15 when low power setting of ultrasonics were used for the retrograde cavity preparation (p<0.05).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.266-273
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• 1996

To obtain basic information on forage sorghum F$_1$ hybrid breeding a total of 16 lines were selected from 311 introduced sorghum germplasm accessions, assessed and classified by the taxonomic distance and principal component analysis. The lines of which plant height and morphological characters were diverse and the 50% flowering date was similar to each other, were selected for parental lines in sorghum $\times$ sweet sorghum and sorghum $\times$ sudangrass crossing groups. Three varietal groups were classified by the average linkage cluster analysis based on the D$^2$ computed in eleven characters. Group I, II and III included 6 lines of sudangrass, 4 lines of sweet sorghum and 6 lines of grain sorghum, respectively. In the result of principal component analysis for eleven characters, about 82% of total variation could be appreciated by the first four principal components, the first principal component was highly loaded with head compactness and shape, l00-seed weight, plant color and grain covering, the second principal component with flowering date, plant height and awnness.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.5 no.1
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• pp.9-14
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• 2012

Purpose: The purpose of the study was to evaluate the accuracy and clinical outcome of ultrasound-guided glenohumeral joint steroid injection on adhesive capsulitis. Materials and Methods: Patients who were diagnosed as adhesive capsulitis by MRI and physical examination and did not improve their symptom with physical therapy and NSAIDS treatment more than 6 months were included in the study. Patients who showed any other shoulder pathology or history if trauma were excluded from the study. 33 patients including 15 males and 18 females were enrolled in the study, the average age being 55.1 (age 42~72). Cocktail of steroid, lidocaine, saline and contrast medium injected inside shoulder glenohumeral joint using novel approach (which we called acromioclavicular approach) under ultrasound guidance. Clinical outcome was measured through passive range of motion and VAS scoring system. Results: Based on radiographic findings, cases were classified according to the leakage of contrast medium; perfect confinement of contrast-medium inside the capsule, partial leakage of the medium and contrast-medium found at outside the joint. Total 25 cases (76%) out of 33 cases showed perfect confinement of contrast-medium inside the glenohumeral joint. Partial leakage was observed in 6 cases (18%), and contrast medium was observed outside of the glenohumeral joint in 2 cases (6%). Perfect-confinement group showed $111^{\circ}$($80{\sim}140^{\circ}$) of forward flexion and $48^{\circ}$($0{\sim}90^{\circ}$) of external rotation before injection, and improved to $134^{\circ}$($90{\sim}150^{\circ}$) of forward flexion and $70^{\circ}$($30{\sim}90^{\circ}$) of external rotation after injection (p<0.01). Partial leakage showed $120^{\circ}$($90{\sim}150^{\circ}$) of forward flexion and $70^{\circ}$($10{\sim}90^{\circ}$) of external rotation before injection, and improved to $139^{\circ}$($135{\sim}140^{\circ}$) of forward flexion and $78^{\circ}$($50{\sim}90^{\circ}$) of external rotation after injection (p<0.01). VAS score improved from 7.1 (score 3~9) to 2.6 (score 0~5) (p<0.01) in perfect confinement group, from 7.5 (score 7~9) to 3.3 (score 2~4) (p<0.01) in partial leakage group. Two group showed no significant difference. Conclusion: Accuracy of Acromioclavicular approach was 94% which is better than any other methods published so far. Partial leakage of the injection material did not show inferior result compared to perfect injection.

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.88-96
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• 2010

Zoysiagrass, especially Jungji implicating medium-leaf type zoysiagrass has been widely used in South Korea recently. This study was carried out to classify 36 selected medium-leaf type zoysiagrass accessions compared to 5 basic zoysiagrass species using RAPDs. Morphological characteristics such as leaf width, leaf angle, leaf sheath length, existance of trichomes and stolon color were measured as useful characteristics for identification of species in Zoysia genus. Nineteen RAPD markers were identified using 8 selected random primers. The dissimilarity coefficient of variants ranged from 0 to 0.736. Three zoysiagrass groups were clustered by dissimilarity coefficient analysis. Group 1 consisted of Z. japonica and some US varieties including 'Zenith' and 'Meyer'. Group 2 consisted of Z. sinica, Z. macrostachya and Korean commercial varieties such as 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type grasses. Group 3 was genetically distinct from Group 1 and Group 2, and included Z. matrella and Z. tenuifolia. 'Anyang', 'Samdeock', and 'Pyeongdong' medium-leaf type zoysiagrasses showed very close genetic relationship with Z. sinica and Z. macrostachya.