• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.161-175
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• 1996

There were many reports that elevations in the levels of active and latent collagenase in gingival crevicular fluid(GCF) have been correlated positively with periodontal disease activity. To provide a simple diagnostic approach for testing GCF collagenolytic activity, the detection limit of enzyme activity was compared using radiofibril assay(Sodek et.al.1981) and spectrophotometric collagenolytic assay(Nethery et al. 1986). The detection limits of both assay for standard bacterial enzyme were similar and the radiofibril assay showed a little (1/2) lower detection limit for tad pole collagenase. To evaluate the relationship between periodontal tissue destruction and the collagenolytic activity, GCF was collected, and latent and active enzyme activities were measured by a spectrophotometric collagenolytic assay. Twelve subjects showing progressive lesions were selected according to the presence of immediate tissue destruction, frequent abscess formation, and increasing need for tooth extraction, and the absence of underlying systemic disease and previous antibiotic medication history within 6 months. Comparisons were made between sites with either: 1) inflammation with a previous history of progressive loss of periodontal tissue and bone support(2l progressive sites): 2) previous history of bone loss and periodontal destruction but now clinically stable(12 comparably stable sites); or 3) no loss of periodontal tissue and bone support(11 control sites including 5 gingivitis sites and 6 healthy sites). Active collagenase activity was the highest in the progressive sites and decreased in the order of the gingivitis sites, the stable sites, and the healthy sites. The total enzyme activity was $2{\sim}3$ fold higher in the progressive sites and the gingivitis sites, compared to the stable and the healthy sites. The ratio of active to total collagenolytic activity was twice in the progressive sites. Analysis of active collagenase level(5mU) and the ratio of active to total collagenolytic activity(0.8) as a diagnositic test indicates that these measurements have the sensitivity of 0.81 and 0.86, the specificity of 0.70 and 0.65, and the overall agreement of 0.75 and 0.73, respectively. Thus, this method has significant merits as a diagnostic tool to determine wherher the site is in a state of remission or progression.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.169-182
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• 2017

Iron and nitrogen codoped carbon (Fe-N/C) catalysts have emerged as one of the most promising replacements for state-of-the-art platinum-based electrocatalysts for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells. During the last decade, significant progress has been achieved in Fe-N/C catalysts in terms of ORR activity improvement and active site identification. In this review, we focus on recent efforts towards advancing our understanding of the structure of active sites in Fe-N/C catalysts. We summarize the spectroscopic and electrochemical methods that are used to analyze active site structure in Fe-N/C catalysts, and the relationship between active site structure and ORR activity in these catalysts. We provide an overview of recently reported synthetic strategies that can generate active sites in Fe-N/C catalysts preferentially. We then discuss newly suggested active sites in Fe-N/C catalysts. Finally, we conclude this review with a brief future outlook.

• 대한가정학회지
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• 제41권1호
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• pp.187-211
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• 2003

This study deals with activities in internet, including activities on consumer counseling, exchange of consumer information, and anti-sites. Among consumers having utilized those three types of internet sites, this study examines whether their satisfactions on them differ depending on their socio-demographic characteristics and types of activities and also explores which factors critically influence consumer satisfactions. According to the results of this study, consumers' satisfactions were higher when consumers evaluated counselors were objective, rapid, and reliable. Thus, Counselors must be more efficiently classify counseling contents, systematically manage, rapid, active and concrete answers for consumers applying for counseling. Second, in the case of consumer information site, the consumer satisfaction turns out to be positively related with exchange of consumer information, rapid provision of information, and reliability. Connection of relevant specialized information, encouragement of active information exchange among consumers, and objectivity and specialty in consumer information site are necessary to increase the quality of internet consumer information cite. Third, in the case of anti site, consumer satisfaction is higher in cases of consumer being joined in anti-site and in cases of objective and reliable sites. In order to facilitate the utilization of anti-sites, those solutions include systematic classification and management of writings listed in the site, active management of the site managers, reducing criticisms on the writings listed and objectivity of information provided, and active searches for solutions. Finally, in order to preserve consumer sovereignty, policy suggestions include improvements of service qualities provided in internet sites, active advertisement, improvement of site management through charging some fees for users, enhancing specialties.

• Restorative Dentistry and Endodontics
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• 제25권4호
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• pp.587-598
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• 2000

Urea in the oral cavity is hydrolyzed mainly by bacterial ureases to ammonia, which in turn, raises pH of the oral environment, maintaining oral pH homeostasis, thereby inhibiting dental caries. Streptococcus salivarius has been shown to be a major contribution to oral ureolysis. Synthesis of urease by S. salivarius appears to be constitutive, but can be greatly enhanced in the acidic environment. It has been presumed that ureolytic activity of S. salivarius strains isolated from caries-active site is greater than that of strains from caries-free site. However, no in vivo study has supported the presumption. The present study was performed to observe the ureolytic activity of S. salivarius strains isolated from different environments in the same individual, finding out whether the ureolytic activity is related to dental caries. For the purpose, S. salivarius strains were isolated from caries-active site (>C2), a caries-free site of the tooth, and the dorsum of the tongue of each of 50 patients having decayed teeth. The strains isolated from the patients who harbored S. salivarius in more than two sites were selected and then their ureolytic activities were measured. In order to examine clonal diversity of the strains, their ureC genes were amplified by polymerase chain reaction (PCR) and then restricted with EcoRV, and the protein profiles of the strains were compared by SDS-PAGE. The results were as follows: 1. Of 50 patients, 13 patients harbored S. salivarius in more than two sites; a total of 61 S. salivarius strain were isolated from the patients and selected for the study. 2. Of 17 isolates from the caries-active site of 9 patients harboring S. salivarius in more than two sites including carious lesion, 10 (58.8%) showed a high ureolytic activity (> 200 ${\mu}mol/min/mg$). While, 19 out of 44 isolates (43.2%) from the caries-free site of the teeth and the dorsum of the tongues of 13 patients were the strains with a high ureolytic activity. 3. Of 9 patients harboring S. salivarius in more than two sites including caries-active site. 6 patients were found to have the strains in the caries-active site showing a lower ureolytic activity than the strains in the other sites. 4. Of 34 isolates with ureolytic activity higher than 40 ${\mu}mol/min/mg$, 32 isolates produced 0.54-Kbp PCR products regardless of the sites of bacterial collection. In contrast, of 27 isolates with ureolytic activity lower than 40${\mu}mol/min/mg$, 26 isolates yielded 1.3-Kbp PCR products or none regardless of the sites. 5. Different clonal types of S. salivarius with relatively higher and lower ureolytic activities were found in the same individuals and even in the same sites. 6. None of strains showing different ureolytic activity appeared to be the same clonal type. The overall results suggest that ureolytic activity of the isolates does not appear to be related to differences of the environments but related to their own genetic traits.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.68-72
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• 1992

Aeromonas, salmonicida YA7-625가 생산하는 chitinase는 $Hg^{2+}$에 의해 저해를 받았으나, $\beta$-mercaptoethanol 처리에 의해서 활성이 보호되었으며 Na-thiosulfate, ascorbic acid등의 환원제들과 sodium azide, p-CMB 등의 -SH 저해제에대하여 전혀 작용을 받지 않았으므로 본 효소의 활성중심에는 -SH가 없는 것으로 생각되었다. 또한 histidine, cysteine, tyrosine 및 trytophan에 작용하는 iodine에 의하여 저해를 받았으며 tryptophan에 대해 특이적으로 작용하는 N-bromosuccinimide에 의해 실활되는 것으로 보아 활성중심에 tryptophan, histidine 및 tyrosine 가 존재하는 것으로 생각되었다.

• 정보보호학회논문지
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• 제15권6호
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• pp.3-12
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• 2005

최근 웹사이트들은 HTML과 스크립트 언어의 한계를 뛰어넘어 사용자에게 다양한 서비스를 제공하기 위해 많은 ActiveX Control 들을 배포하고 있다. 하지만, ActiveX Control은 웹 페이지나 이메일을 통해 실행될 수 있기 때문에 안전하지 못한 ActiveX Control은 개인 PC 보안에 치명적인 약점이 될 수 있다. 그럼에도 불구하고 대부분의 ActiveX Control들은 안전성에 대한 검증 없이 사용자들에게 배포되고 있어 많은 개인 PC들이 외부의 침입에 노출되고 있다. ActiveX Control 취약점을 줄이기 위해서는 제 3자에 의한 취약점 검사와 검증이 필요하다. 본 고에서는 점검대상 식별부터 Reverse Engineering까지 ActiveX Control 의 취약점 검사를 수행하기 위한 절차와 관련 기술들에 대해 기술한다. 또한 ActiveX Control 경우 일반 응용프로그램과 다를 뿐만 아니라 국내 환경과 국외환경의 차이로 인해 기존의 취약점 검증 기법들을 그대로 적용할 수 없다. 본 고에서는 ActiveX Control 취약점 검증을 위해 필요한 요소기술들에 대해 기술한다.

• 한국식품영양학회지
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• 제7권1호
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• pp.1-7
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• 1994

To investigate the characteristics of active sites of the D-xylanase and $\beta$-xylosidase purified from Penicillium verruculosum, effects of various chemicals on the enzyme activity were analyzed. The D-xylanase was activated by Cua), however it was inhibited by metal ions, Hg2+ and Mna+, by chemicals, N-bromosuccinimide, iodine, diethylpyrocarbonate, and 2,3-butanedione. These results suggested that the D-xylanase from Penicillium verruculosum contained tyrosine, histidine, arginine and tryptophan at the active center. The $\beta$-xylosidase was inhibited by Hg2+, N-bromosuccinimide and sodium dodecyl sulfate, however it was not effected by Mn2+ and Cu2). It was suggested that the enzyme contained tryptophan at the active center.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7725-7730
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• 2013

Objective: The purpose of this study was to evaluate secondhand smoke (SHS) exposure inside selected public places to provide basic data for the development and promotion of smoke-free policies. Methods: Between March and May 2009, an SHS exposure survey was conducted. $PM_{2.5}$ levels and air nicotine concentrations were measured in hospitals (n=5), government buildings (4), restaurants (10) and entertainment venues (10) in Seoul, Republic of Korea, using a common protocol. Field researchers completed an observational questionnaire to document evidence of active smoking (the smell of cigarette smoke, presence of cigarette butts and witnessing people smoking) and administered a questionnaire regarding building characteristics and smoking policy. Results: Indoor $PM_{2.5}$ levels and air nicotine concentrations were relatively higher in monitoring sites where smoking is not prohibited by law. Entertainment venues had the highest values of $PM_{2.5}$(${\mu}g/m^3$) and air nicotine concentration(${\mu}g/m^3$), which were 7.6 and 67.9 fold higher than those of hospitals, respectively, where the values were the lowest. When evidence of active smoking was present, the mean $PM_{2.5}$ level was 104.9 ${\mu}g/m^3$, i.e., more than 4-fold the level determined by the World Health Organization for 24-hr exposure (25 ${\mu}g/m^3$). Mean indoor air nicotine concentration at monitoring sites with evidence of active smoking was 59-fold higher than at sites without this evidence (2.94 ${\mu}g/m^3$ vs. 0.05 ${\mu}g/m^3$). The results were similar at all specific monitoring sites except restaurants, where mean indoor $PM_{2.5}$ levels did not differ at sites with and without active smoking evidence and indoor air nicotine concentrations were higher in sites without evidence of smoking. Conclusion: Nicotine was detected in most of our monitoring sites, including those where smoking is prohibited by law, such as hospitals, demonstrating that enforcement and compliance with current smoke-free policies in Korea is not adequate to protect against SHS exposure.

• Child Health Nursing Research
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• 제12권1호
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• pp.57-64
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• 2006

Purpose: This study was conducted to analyze web sites that provide child-care information and to provide a proper model for child-care web sites. Method: The evaluation tool with 23 items including purpose, contents, timeliness and reliability, interaction, and function was developed and modified. Quantitative analyses of 48 web sites, which were selected using popular search engines, were done. Result: 1) The aim of the web site was clearly shown for 24 sites (63.2%) and 17 sites (44.7%) provided the information for judging whether the informant was an expert. 2) Most web sites provided information on feeding, nutrition, and common health problems, and 11 sites provided information on care of problem behavior, but only 6 sites provided information on mother-infant interaction. 3) Timely information was provided on 21 sites, however none of the sites provided information sources. 4) Methods for contact the authors were found for 31 sites (81.6%) and 19 sites (50%) had active bulletin boards to receive opinions from users. 5) There were 32 sites where information could be found by clicking less than 3 times. Conclusion: We suggest that the evaluation criteria for child-care web sites used in this study is a tool that can be used to evaluate web sites with consistency, but there is a need for further study to develop standardization of the evaluating tool.

• Journal of Periodontal and Implant Science
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• 제25권3호
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• pp.733-740
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• 1995

This investigation was undertaken to determine the relationship between the amount of polymorphonuclear leukocyte(PMN) enzyme myeloperoxidase(MPO) in gingival crevicular fluid(GCF) collected from active or control site and gingival disease status described by clinical indices(gingival index, papillary bleeding index, pocket depth, periotron unit). The results were as follows : 1. MPO activity/site was greater at active sites than at control sites. 2. According to increasing the clinical parameters, MPO/sites was higher statistically (P<0. 01, P<0.05). 3. High MPO(unit/site) groups was higher statistically than low MPO(unit/site) groups in various clinical parameters. 4. Correlation coefficients between MPO(unit/site) and GI, MPO($unit/{\mu}l$ GCF) and periotron unit were 0.4782, -0.5901, respectively.