• 대한치과보철학회지
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• 제46권3호
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• pp.307-319
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• 2008

STATEMENT OF PROBLEM: It is known that an anodic oxidation technique, one of the methods for the implant surface treatment, remarkably increased surface area, enhanced wettability and accelerated the initial bone healing. Purpose: This study was performed to evaluate the wettability of anodized titanium surface which has a nanotubular structure, to assess osseointegration after the placement of implant with nano-size tubes on tibia of rats and to analyze quantitatively transferable rhBMP-2 on each surface. MATERIAL AND METHOD: Four different kinds of surface-treated titanium discs (polished (machined surface) group, micro (blasting surface) group, nano (anodizedmachined surface) group, and nano-micro (anodized-blasting surface) group) were fabricated (n=10). Three different media were chosen to measure the surface contact angles; distilled water, plasma and rhBMP-2 solution. After a single drop (0.025 $m{\ell}$) of solution, the picture was taken with the image camera, and contact angle was measured by using image analysis system. For the test of osseointegration, 2 kinds of anodized surface (anodized-machined surface, anodized-blasting surface) implants having 2.0 mm in diameter and 5.0 mm in length inserted into the tibia of Wistar rats. After 3 weeks, tibia were harvested and the specimens were stained with hematoxylin and eosin for histological analysis. To test the possibility of drug delivery, after soaking sample groups in the concentration of 250 ng/$m{\ell}$l of rhBMP-2 for 48 hours, the excess solution of rhBMP-2 were removed. After that, they were lyophilized for 24 hours, and then the rhBMP-2 on the surface of titanium was resolved for 72 hours in PBS. All the extracted solution was analyzed by ELISA. One-way analysis of variance (ANOVA) was performed on the data. RESULTS: The wettability is improved by anodic oxidation. The best wettability was shown on the nano-micro group, and it was followed by nano group, micro group, and polished group. In the histological findings, all implants showed good healing and the new bone formation were observed along the implant surface. After 3 days, nano-micro group delivered the most amount of rhBMP-2, followed by nano group, micro group, and polished group. CONCLUSION: It indicated that anodic oxidation on blasting surface produce functionally graded nano-micro porous structure and enhance hydrophilicity of the surface and osseointegration. The findings suggest that the nano-micro porous structure could be a useful carrier of osteogenic molecules like rhBMP-2.

• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.251-264
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• 1999

본 연구는 조기발병형 치주염의 서로 다른 4가지 표현형에 있어서 Porphyromonas gingivalis(Pg) 381과 Actinobacillus actinomycetemcomitans(Aa) Y4에 대한 상승된 IgG subclass의 양상을 평가하기 위해 시행하였다. Subform I(distinctive localized juvenile periodontitis pattern)에서 3명 subform II(post juvenile periodontitis pattern)에서 19명, subform III (localized but rapidly progressing pattern)에서 15명, subform IV(distinctive rapidly progressing periodontitis pattern)에서 15명의 환자를 조사하여 Pg에 대한 그들의 total IgG level과 각각의 IgG subclass level 및 Aa에 대한 IgG level을 검사했다. Pg에 대한 total IgG level은 subform II와 IV보다 subform I과 III에서 훨씬 높게 나타났다. IgG3 level이 subform I과 IV사이에서 현저한 차이가 있다는 점을 제외하고는, 다른 IgG subclass level에서 subform 사이에 아무런 차이가 없었다. Pg에 대한 IgG subclass는 single class 혹은 다양한 group에서 상승되어 나타났으며, IgG1+2+4가 가장 흔하게 발견되었고, 다음으로 IgG4 단독, IgG2 단독, IgG2+4, IgG2+3+4의 순으로 발견되었다. IgG2와 IgG4가 빈번히 상승되어 발견되었는데, 특히 severe form(subform III & IV)에서 그러했다. 뿐만 아니라, IgG level은 subform II, III, IV와 일치하여 점차적으로 증가하였고, 반면에 IgG1/IgG4 ratio는 그와 일치하여 감소되었다. 이러한 ratio의 감소는 단백질성의 오래된 항원의 과부하로 인해 immunoglobulin gene의 전환을 가능하게 한다는 것을 나타내고 있다. Aa에 대한 IgG2 level은 다른 유형보다 subform I에서 상당히 높았다. Pg에 대한 IgG2 levels이 subform I의 국소 부위에서 발생하는 disease activity와 밀접한 관련이 있으며, Aa의 경우에는 이러한 관련성이 나타나지 않았다. Pg에 대한 IgG2 level은 18-25세에서 훨씬 높은 동시에 26-35세에서는 감소했으며 결국 30대 후반에서는 더 높은 수치로 되돌아갔다. 이러한 결과는 Pg에 대한 IgG2 및 IgG responsiveness (single 혹은 combined)가 EOP의 severe form의 발달에 중요하게 작용하며 IgG2 levels은 IgG1/IgG4 ratio와 더불어 EOP의 localized type이 generalized type으로 계속 진행하는 것을 조절하는 역할을 하는 것으로 보인다는 것을 강하게 시사하였다.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.470-477
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• 1995

Flavonoids from Scutellariae Radix possessed a dual function both as an anti-inflammatory agent and an enhancer of cellular activity in gingival fibroblast. The purpose of this study was to evaluate on the toxicity of ethanolic extract from the root of Scutellariae Radix Georgi and its flavonoids, Wogonin, Baicalein, and Baicalin were isolated and purified by the following method. The crude drug was extracted with ethyl acetate and the residue was dissolved in ethyl alcohol. The ethyl alcohol soluble fraction was separated, concentrated, and then chromatographed on a silica gel column. The acute oral LD 50 in rats was determined for EtOH ex. of Scutellariae Radix and three compounds were evaluated with a single oral gavage at three graded dosage levels. The acute intravenous LD 50 was determined with a single intravenous injection via the jugular vein at three graded dosage levels. Groups of 5 male and 5 female rats, 6 week of age at the start of the study, were fed diets containing 3 graded dosage levels for 14 days. Groups of 5 male and 5 female hamster received O.5ml of the test article at once in a day for 5 days to the buccal cheek pouch for two minutes each. The acute oral LD50 for EtOH ex. of Scutellariae Radix is 1430mg/kg, and for Wogonin 1320mg/kg, for Baicalein 1250mg/kg, for Baicalin 1330mg/kg. The acute intravenous toxicity of EtOH ex. of Scutellariae Radix and its extracts was found to be 27mg/kg body weight No toxic effects were observed in rats fed up to 200mg/kg of EtOH ex. of Scutellariae Radix, Wogonin, Baicalein and Baicalin in the diet for 14 days. The acute Mucouse Membrane LD 50 in hamsters was found to be greater than 100mg/kg. These results suggested that EtOH ex. of Scutellariae Radix and its flavonoids are safe for oral care products using limited amount of extract.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.486-492
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• 2014

Background We conducted this study to identify the correlation between the time to surgery and that to recovery from postoperative diplopia. Methods In the current single-center, retrospective study, we enrolled a total of 11 patients (n=11) who were diagnosed with white-eyed blowout fracture and underwent surgical operation at our institution between January 2009 and January 2013. To identify the correlation between the time to surgery and that to recovery from postoperative diplopia, we divided our patients into the three groups: the group A (time to surgery, <2 days) (n=4), the group B (time to surgery, 3-7 days) (n=4) and the group C (n=3) (time to surgery, 8-60 days). Then, we compared such variables as sex, age, signs of soft tissue injury, preoperative nausea/vomiting, the degree of preoperative diplopia and the side of the fracture on computed tomography scans between the three groups. Results In our series, mean age at the onset of trauma was nine years (range, 5-16 years); the mean time to surgery was 30 days (range, 2-60 days); and the mean follow-up period was one year (range, 6 months-2 years). Our results showed that the time to recovery was shorter in the patients with a shorter time to surgery. Conclusions We found that the degree of recovery from impaired ocular motility and diplopia was the highest in the patients undergoing surgical operations within 48 hours of the onset of trauma with the reconstruction of the fracture sites using implant materials.

• Journal of Periodontal and Implant Science
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• 제44권6호
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• pp.280-287
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• 2014

Purpose: The purpose of this randomized single-blind controlled trial was to elucidate the clinical and antimicrobial effects of daily phototherapy (PT) as an adjunct to scaling and root planing (SRP) in patients with chronic periodontitis. Methods: The study was conducted from December 2013 to May 2014 at Ewha Womans University Mokdong Hospital, Seoul, Korea. Forty-one patients with mild to moderate chronic periodontitis were randomly divided into two therapeutic groups in a 1:1 ratio: SRP+PT and SRP (control) groups. All participants underwent full-mouth SRP. PT was performed thrice a day for a month by using electric toothbrushes with embedded light-emitting diodes. Plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing were assessed before (baseline) and four weeks after (follow-up) the treatment. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Campylobacter rectus, Eikenella corrodens, Streptococcus mutans, and Streptococcus sobrinus levels were detected by a real-time polymerase chain reaction at the same points in time. Results: The clinical parameters improved in both the groups. At the follow-up assessment, PPD was significantly decreased in the SRP+PT group (P=0.00). Further, PPD and CAL showed significantly greater changes in the SRP+PT group than in the SRP group (PPD, P=0.03; CAL, P=0.04). P. gingivalis and T. forsythia levels decreased in this group, but no significant intergroup differences were noted. Conclusions: Adjunctive PT seems to have clinical benefits, but evidence of its antimicrobial effects is not sufficient. Long-term studies are necessary to develop the most effective PT protocol and compare the effectiveness of PT with and without exogenous photosensitizers.

• 대한의용생체공학회:의공학회지
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• 제32권3호
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• pp.198-206
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• 2011

Hearing devices like cochlear implant, vibrant soundbridge, etc. try to offer better sound for people. In hearing devices, several beamformers including conventional directional microphone are applicable to noise reduction. Each beamformer has different directional response and it could change sound intelligibility or quality for listeners. Therefore, we investigated the performance of three beamformers, which are first and second order directional microphone, and broadband beamformer(BBF) with a computer simulation assuming hearing device microphone configuration. We also calculated objective measurements which have been used to evaluate speech enhancement algorithms. In the simulation, a single speech and a single babble noisewere propagated from the front and $135^{\circ}$ azimuth degrees respectively. Microphones were configured in an end-fire array and the spacing was varied in comparison. With 3 cm spacing, BBF had about 3 dB higher enhanced SNR than that of directional microphones. However, enhancement of segmental SNR and frequency weighted segmental SNR were similar between the first order directional microphone and broadband beamformer. In addition when steady state noise was used, broadband beamformer showed the increased performance and had the highest enhanced SNR, and segmental SNR.

• 한국결정성장학회지
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• 제9권3호
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• pp.327-333
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• 1999

Ion implantation, photo-lithography, Ar ion milling, hot press를 이용한 micro-fabrication 방법으로 고순도 단결정 알루미나 표면에 Ca를 제한된 양으로 첨가하고, 내부에 여러 가지 형태의 기공을 갖는 bi-crystal을 만들었다. 이 bi-crystal 고순도 알루미나에 미치는 Ca의 영향을 평가하기 위하여 내부 기공의 형태 변화와 결정의 성장을 열처리에 따라 광학현미경으로 관찰하였다. 열처리에 따라 inner crack-like pore의 내부표면에 dot와 육각형의 형태를 갖는 결정 입자가 생성되는 것을 관찰할 수 있었다. $1,500^{\circ}C$로 열처리한 경우에 CaO . $6Al_2O_3$로 생각되는 bar 형태의 결정이 표면에 석출되는 것이 관찰되었으며, 이 결정이 $1,600^{\circ}C$에서 열처리하면 사라지는 것으로 보아 이 온도 부근에서 알루미나에 대한 Ca의 solubility limit 또는 diffusion rate가 변화하는 것으로 생각된다.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.401-411
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• 2005

The aim of this study was to determine the minimal inhibitory concentration(MIC) of cefixime, which is a 3rd generation of cefalosporin, against 6 species of putative periodontopathogens; Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Prevotella nigrescens, Tannerella forsythia and Porphyromonas gingivalis. The efficacy of cefixime was examined by comparing it with that of several antibiotics(amoxicillin, $Augmentin^{(R)}$ ciprofloxacin, metronidazole, and tetracycline), which were used as the control. The MIC was measured using a microdilution method. The MIC of cefixime against the putative periodotopathogens, as a single use regimen, was relatively lower than that of the other antibiotics. The MIC of cefixime/metronidazole against P. intermedia ChDC KB14, P. nigrescens ChDC KB50, F. nucleatum ChDC PV-F37, F. nucleatum ChDC F130, and F. nucleatum ChDC F175, as a simultaneous regimen, was lower than that of the other antibiotics. The concentration of cefixime in the crevicular fluid of volunteers who received 250mg every 12 hours for 3 days was $9{\mu}g/ml$ after 9 hours. In conclusion, cefixime showed good antimicrobial activity in a single treatment or as a combined therapy with amoxicillin, $Augmentin^{(R)}$ or metronidazole against 6 periodontopathogens.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권4호
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• pp.312-317
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• 2004

High dose ($3{\times}10^{16}cm^{-2}$) implantation of Fe or Ni ions into bulk, single-crystal ZnO substrates was carried out at substrate temperature of ${\sim}350^{\circ}C$ to avoid amorphization of the implanted region. The samples were subsequently annealed at $700^{\circ}C$ to repair some of the residual implant damage. X-Ray Diffraction did not show any evidence of secondary phase formation in the ZnO. The Ni implanted samples remained paramagnetic but the Fe-implanted ZnO showed evidence of ferromagnetism with an approximate Curie temperature of ${\sim}$240K. Preliminary X-Ray Photoelectron Spectroscopy measurements showed the Fe to be ill the 2+ oxidation state. The earrler density in the implanted region still appears to be too low to support carrier-meditated origin of the ferromagnetism and formation of bound magnetic polarons may be one potential explanation for the observed magnetic properties, No evidence of the Anomalous Hall Effect could be found in the Fe-implanted ZnO, but its transport properties were dominated by the conventional or ordinary Hall effect.

• 대한전자공학회논문지SP
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• 제47권3호
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• pp.70-80
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• 2010

본 논문에서는 치과용 의료시스템(Dental PACS)에서 필요한 시계열 분석(Subtraction Radiography) 방법에 기반 하여 기존의 연구에서 갖지 못했던 영상정렬의 자동화 방안과 미세변화 검출 방안을 제안한다. 제안된 방법은 기존의 단일 템플릿 방식의 문제점을 해결하기 위해 인공치아 및 자연치아의 기하학적 형태 정보를 이용하여 각 치아에 대한 관심영역을 획득하고 획득된 관심영역을 기준으로 지식 기반(knowlege-based)의 다중 템플릿(multi-template) 방식의 정합을 통해 치아 주위에서 발생되는 미세변화를 빠르고 정확하게 검출할 수 있다. 실험결과 제안된 방법은 신속하고 정확하게 치아 주위의 미세변화에 대한 검출이 가능하였고, 보다 객관적이고 정량적인 결과를 제시할 수 있음을 보여주었다.