• 대한치과의사협회지
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• 제40권7호통권398호
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• pp.542-547
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• 2002

This study was aimed to help diagnose the vertical root fractures in endodontically and in nonendodontically treated teeth. This was a study about mine teeth with a vertical root fractures. Four cases were nonendodontically treated teeth and five cases were endodontically treated teeth. A collection of information including past dental history, periodontal probing, and X-ray was gathered on each case. One of the endodontic cases had no periodontal pocket depth and was in acute pain. It was confusing to find whether causes were because of endodontic failure or vertical root fractures. Most of the vertical root fractures were found in patients aged between 50 and 60. Vertical root fractures were found in the molar and premolar of maxillary and mandibular teeth. The second molars repecially, which had C shaped roots had vertical root fractures with apical propagation type. The apical propagation type means that vertical root fracture initiates in root apex and propagate to coronal root. The teeth with vertical root fractures of the apical propagation type, which was in acute pain, were very difficult in differential diagnosis of periodontal lesion and endodontic failure. Therefore, the dental history was very important to make a differential diagnosis. Past pain history repeated uncomfortable symptoms in bite was a key of differential diagnosis.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
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• pp.127-131
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• 2006

Depot have a lagged behind structure in the side of building up the view. With this reason, people have been recognized depot as hatred facility causes to have car noise, air pollution. In the other hand, depot become a underground and complex facility as a higher-value added building, and moreover, it need to understand the environment that depot structure have a specific field condition to apply green roof system. 1) Analysis proper waterproofing material and root barrier apply to depot need root penetrating test method 2) Suggest root barrier and waterproofing material relate to maintain and construction for green roof system 3) Construction condition for depot have crack movement of structure by vehicle vibration and root penetrating force by plant growth

• 한국균학회지
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• 제50권1호
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• pp.41-46
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• 2022

Gastrodia elata infected with root rot disease was collected from cultivated G. elata fields in Gimcheon, Korea, in 2018. G. elata tuber surfaces exhibited root rot disease symptoms of dark-grey lesions and white fungal mycelial growth. The fungus was isolated from symptomatic tubers and cultured. Based on morphological characteristics and molecular analysis of the internal transcribed spacer region of ribosomal DNA and translation elongation factor 1-alpha, the isolated fungus was Fusarium oxysporum. This is the first report of root rot caused by F. oxysporum on G. elata tubers in Korea.

• Journal of Periodontal and Implant Science
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• 제25권1호
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• pp.76-88
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• 1995

The purpose of this was to evaluate the in vitro effects of different application modes of tetracycline HCI on dentin root surfaces. The study group was comprised of 30 teeth with advanced periodontal disease extracted before the start of periodontal therapy. The diseased root surface was vigorously root planed to expose dentin. The teeth were sectioned and cotton pellets. soaked in a saturated solution of tetracycline HCI, were either "placed" or "burnished" on the prepared root surface for 3, 5 min. respectively. Control surfaces were similarly treated with root planing only. Following the various treatments, teeth were fixed. dehydrated, critical point dried, and coated for scanning electron microscopic(SEM) evaluation. The surfaces of tetracycline HCI treated specimens considerably differed from specimens treated with root planing only. Results demonstrated that root-planed, no-tetracycline HCI specimens had amorphous, irregular surface which corresponded to a smear layer. Tetracycline HCI specimens exhibited collagen fibers and dentinal tubules exposed by the removal of the smear layer. Although some differences were seen in surface structures among some specimens. "burnished" application causes more extensive change than "placed" application, and application time of the tetracycline HCl did not seem to have any major impact on the surface morphology.

• 대한치과교정학회지
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• 제51권4호
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• pp.241-249
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• 2021

Objective: This study aimed to evaluate the volume, amount, and localization of root resorption in the maxillary first premolars using micro-computed tomography (micro-CT) after expansion with four different rapid maxillary expansion (RME) appliances. Methods: In total, 20 patients who required RME and extraction of the maxillary first premolars were recruited for this study. The patients were divided into four groups according to the appliance used: mini-implant-supported hybrid RME appliance, hyrax RME appliance, acrylic-bonded RME appliance, and full-coverage RME appliance. The same activation protocol (one activation daily) was implemented in all groups. For each group, the left and right maxillary first premolars were scanned using micro-CT, and each root were divided into six regions. Resorption craters in the six regions were analyzed using special CTAn software for direct volumetric measurements. Data were statistically analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test with Bonferroni adjustment. Results: The hybrid expansion appliance resulted in the lowest volume of root resorption and the smallest number of craters (p < 0.001). In terms of overall root resorption, no significant difference was found among the other groups (p > 0.05). Resorption was greater on the buccal surface than on the lingual surface in all groups except the hybrid appliance group (p < 0.05). Conclusions: The findings of this study suggest that all expansion appliances cause root resorption, with resorption craters generally concentrated on the buccal surface. However, the mini-implant-supported hybrid RME appliance causes lesser root resorption than do other conventional appliances.

• 열병합발전
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• 통권30호
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• pp.21-25
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• 2002

According to recent Korea Electric Power Company report, yearly distribution line brass cramp bolts failure summed up to 4,400 cases emerging as one of main local break-down causes. Naturally, the need for the investigation was proposed To determine the root cause of the cramp bolt failures, mechanical and metallurgical investigation were performed for 90 samples which collected from various sites. For the understanding of the geometric characteristics, stress distribution was evaluated by CAE program and proof load of each bolts was tested. The SEM&EDS was used for metallurgical investigation. Through the investigation, the root causes of failures were confirmed. All damaged bolts showed intergrannular fracture mode and the all fractured bolt showed ß phase morphology contrast to the a&ß mixture morphology of the non-damaged samples. Additionally, EDS analysis confirmed the existence of lead rich layer on grain boundaries.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.245-248
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• 2006

This paper presents the results from a survey on root causes that led to fatal accidents in construction projects In Vietnam. The survey was conducted by means of structured questionnaires and interviews with relevant individuals such as Foremen, field engineers, and project managers working in construction companies located in Ho Chi Minh City, the largest city of Vietnam. The survey sample consists of in total 91 fatal accident cases that occurred in construction projects during the years 1996-2005 and were recorded in a report at the Vietnam Department of Labor-Invalids-Social Affairs. The current effort is aimed at determining the essential measures for avoiding fatal accidents that have been increasingly taking place in Vietnam construction firms. The findings from the survey provided a necessary basis for determination of critical factors to be used as safety indexes in developing a checklist for preventing fatal accidents in future construction project

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1360-1364
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• 2009

The basic concept of analysis of human error that induced railway accident is that errors are consequences, not causes. But in most cases, it is likely that direct causes of the accident could be concluded as real causes, which make it difficult to find out root causes. Design, training, staffing, culture and condition are general category applied to investigate human error. In order to examine how those approach could help accident analysis, this paper studied accident investigation reports of UK RAIB(Rail Accident Investigation Branch). Rather than consider specific investigation method, we focus investigation result on how to describe causal factors and how to indicate recommendations to prevent similar accident. The reports show that they try to find out causes more in organizational, environmental and job factors, which implies the necessity to improve investigation process of human error accident in Korea.

• 한국의료질향상학회지
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• 제23권1호
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• pp.25-38
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• 2017

Root cause analysis (RCA) is systematic process for identifying contributing factors and root causes. It detects system-level vulnerabilities and prevents them from occurring in the future. In many countries, RCA guidelines have been developed and used for these purposes, and various practical tools are suggested according to stages of RCA implementation. In Korea, adverse events occur in 7.2-8.3 percent of inpatients according to studies conducted in hospitals. However, frontline staffs are suffering from lack of knowledge about RCA implementation. This study introduces RCA guidelines that may be used in hospitals to improve the quality of medical care and patient safety.

• Journal of Ginseng Research
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• 제32권4호
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• pp.337-340
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• 2008

Seedlings of North American ginseng (Panax quinquefolius L.) were grown to full canopy establishment and then leaflet or leaf removal at different times applied to determine the effects on plant growth and performance. Leaf removal at 47, 57, 69 and 78 days after seeding resulted in 82.1, 59.8, 41.3 and 29.8% reduction, respectively, in root dry matter (economic yield) ; this indicates that leaf removal during the early root growth period causes greatest reduction in root yield. Removal of 1, 2, and 3 leaflets at 42, 52, 62 and 70 days from seeding reduced root weight at harvest (80 days from seeding) linearly, particularly at earlier removal dates. The perennating bud formed on all roots and was not influenced by treatment. This would suggest that if leaf loss occurs after canopy establishment the plant will re-grow the next year after the obligatory dormancy period.