• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.639-646
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• 2004

Dental phobia is the most prevalent fear in all age groups, across gender, and in all countries. One of the primary identified sources is the fear of dental injections in the dental phobia or the high dental fear and anxiety groups. The purpose of this study was to clinically evaluate the computer controlled anesthetic device and to compare it with traditional methods of dental anesthetic delivery. Fifty(mean age : 25.6 yrs) systemically and periodontally healthy volunteers participated in this study. The subjects were given contralateral buccal and palatal injections. One side was injected with the computer-controlled anesthetic device with a microprocessor and an electric motor to precisely regulate flow rate during administration : The experimental group. The control side was injected with a standard manual syringe, in which flow rate and pressure are operator-dependent and can't be controlled accurately : The control group. The subjects described their perceived pain experiences with two subjective scales. The results of this study were as follows: 1. The computer-controlled anesthetic device was significantly less painful than conventional syringe injection 2. The female subjects reported more pain than the male subjects. But, there were no statistical differences. 3. The anesthetic effect of both methods did not show any difference. In this study, it may be concluded that pain levels decreased significantly when the computer-controlled anesthetic device was used.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.515-519
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• 2004

Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOV A and the Scheffe test at the 95% confidence level. The results of this study were as follows: 1. The mean fracture strength decrease in following sequence Group 1 (4558.90{\;}\pm{\;}77.40{\;}N$), Group 2 ($494.07{\;}\pm{\;}123.98{\;}N) and Group 3 ($267.33{\;}\pm{\;}27.02{\;}N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.

• Safety and Health at Work
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• v.6 no.4
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• pp.268-278
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• 2015

Background: This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. Methods: The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration ($m/s^2$)], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. Results: More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient ${\beta}=-0.052$, standard error SE = 0.023), manufacturer (${\beta}=1.093$, SE = 0.227), rock hardness (${\beta}=0.045$, SE = 0.018), uniaxial compressive strength (${\beta}=0.027$, SE = 0.009), and density (${\beta}=-1.135$, SE = 0.235). Conclusion: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

• The Journal of Internal Korean Medicine
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• v.41 no.6
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• pp.1015-1029
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• 2020

Purpose: This study assessed the validity of a questionnaire (SEID-Q27) for diagnosis of chronic fatigue syndrome (CFS), designed based on the systematic exertion intolerance disorder (SEID) criteria. Methods: Two groups of participants were recruited: 1. a non-CFS control group: adult university personnel with a Chalder fatigue scale (CFQ) score ≥15, and 2. a CFS patient group: patients from an online CFS community diagnosed with CFS (diagnostic code of G93.3) with the symptoms present. The survey ran from September to October, 2020. The validity of the questionnaire was investigated by factor analysis and receiver operator characteristic (ROC) analysis. Results: Among the 35 adults surveyed, 30 (86%) participants had CFQ scores ≥15 (15 males and 15 females) and 5 (14%) had a CFS diagnosis (2 males and 3 females). The total mean score was significantly different between the two groups (CFS: 6.8±2.2 vs. control: 4.4±2.4, p<0.05). The area under the curve (AUC) was 0.827. With a cut-off point 62, the sensitivity was 60%, specificity 97%, and the discriminant ability of the survey was 79%. Conclusions: The SEID -Q27 appears to be a useful instrument for the diagnosis of CFS using SEID criteria. However, further large-scale studies are needed with greater numbers of participants.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.61-67
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• 2022

Purpose: This study aimed to evaluate the accuracy of bite registration using intraoral scanner based on data trimming strategy for fremitus teeth. Materials and Methods: A reference model was designed by Medit Model Builder software (MEDIT Corp., Seoul). Tooth number 24 and 25 were separated as dies and tooth number 26 was prepared for full-coverage crown. Those were printed using a 3D printer (NextDent 5100). The scanning procedure was performed by a single trained operator with one intraoral scanner (i700; MEDIT Corp.). The scanning groups were divided as follows: group 1 (G1), no fremitus; group 2 (G2), 0.5 mm buccal fremitus in the maxillary left first and second premolar; and group 3 (G3), 1.5 mm buccal fremitus in the maxillary left first and second premolar. Each group was scanned 10 times and were analyzed using the reference model data. Surface-based occlusal clearance was analyzed at the prepared tooth to evaluate accuracy. Result: Mean values of control group (G1) were 1.587±0.021 mm. G2 showed similar values to those from the control group (1.580±0.024 mm before trimming strategy and 1.588±0.052 mm after trimming strategy). G3 showed significantly greater values (1.627±0.025 mm before trimming strategy and 1.590±0.024 mm after trimming strategy) and the differences were found between trimming strategy (P=0.004). Conclusion: Bite trimming strategy for fremitus teeth is a reliable technique to reduce inaccuracies caused by the mobility at maximum intercuspation.

• Applied Microscopy
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• v.51
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• pp.6.1-6.9
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• 2021

Histopathology is a well-established standard diagnosis employed for the majority of malignancies, including breast cancer. Nevertheless, despite training and standardization, it is considered operator-dependent and errors are still a concern. Fractal dimension analysis is a computational image processing technique that allows assessing the degree of complexity in patterns. We aimed here at providing a robust and easily attainable method for introducing computer-assisted techniques to histopathology laboratories. Slides from two databases were used: A) Breast Cancer Histopathological; and B) Grand Challenge on Breast Cancer Histology. Set A contained 2480 images from 24 patients with benign alterations, and 5429 images from 58 patients with breast cancer. Set B comprised 100 images of each type: normal tissue, benign alterations, in situ carcinoma, and invasive carcinoma. All images were analyzed with the FracLac algorithm in the ImageJ computational environment to yield the box count fractal dimension (Db) results. Images on set A on 40x magnification were statistically different (p = 0.0003), whereas images on 400x did not present differences in their means. On set B, the mean Db values presented promising statistical differences when comparing. Normal and/or benign images to in situ and/or invasive carcinoma (all p < 0.0001). Interestingly, there was no difference when comparing normal tissue to benign alterations. These data corroborate with previous work in which fractal analysis allowed differentiating malignancies. Computer-aided diagnosis algorithms may beneficiate from using Db data; specific Db cut-off values may yield ~ 99% specificity in diagnosing breast cancer. Furthermore, the fact that it allows assessing tissue complexity, this tool may be used to understand the progression of the histological alterations in cancer.

• Journal of the Korean Society of Food Culture
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• v.25 no.4
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• pp.357-365
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• 2010

The study surveyed care giver's perceptions of baby food and evaluated the quantitative and qualitative aspects of Korean websites related to the baby food for atopic dermatitis infants. Sources of care giver information about baby food were the internet (93%), clinics (57%), television (52%), oriental clinics (37%), and neighbors (6%). The five most commonly-used internet search engines (Daum, Google, Nate, Naver and Yahoo) were searched using the terms "atopic dermatitis", "weaning food" and "baby food". The searched websites included oriental medical clinics (38.8%), online merchant companies (13.4%), corporations (13.4%), medical clinics (11.9%), related associations (11.9%), public health centers (4.4%) and personal sites (4.4%). Website food and nutrition information included medical information about baby food for atopic dermatitis (92.6%), baby food for atopic dermatitis (67.6%), related community (58.8%), product information (32.4%) and baby food preparation for atopic dermatitis (23.5%). Qualitative evaluation was conducted based on the American Library Association website checklist; Website operator and information sources were provided for 62.7% and 38.8% of the websites, respectively. The purpose of a website was more explicitly stated in medical clinic sites than nonmedical sites. Only 24.2% of websites had a title that appropriately reflected the site's purpose. The majority (92.5%) of the sites were easy to read and understand. Information was judged to be sufficient in 65% of the medical sites and 74.1% of non-medical sites. A feedback menu and search function were enabled in 85.1% and 28.4% of the sites, respectively. The mean score for quality grade was 14.64 (range 9-19). In conclusion, in order to improve the information of baby food for atopic dermatitis infants in websites, accurate information by experts and continuing monitoring are highly required.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.464-470
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• 2023

Objectives: This study evaluated occupational exposures to noise and heat stress during routine non-outage works in three coal-fired power plants in the Republic of Korea. Methods: The data were collected during the summer of 2020. Full shift noise exposure of 52 workers were measured using noise dosimeters. Heat stress of 16 worksites were measured for 70 minutes using wet-bulb globe temperature monitors. Results: The noise dosimetry results revealed time-weighted averages that ranged from 47.5 to 88.9 dBA. 2 out of 52 noise measurements exceeded 85 dBA. Based on the arithmetic mean, the coal service group showed the highest level at 80.2 dBA by job tasks. Noise exposures exceeding 85 dBA were measured in the coal service and plant operator group. Heat stress index measurements ranged from 20.3℃ to 37.2℃. 1 out of 9 indices measured in coal facilities and 4 out of 7 indices measured in boiler house exceeded 1 hour TWA during moderate work. Heat stress indices measured from boiler houses were significantly higher than those measured from coal equipment. Conclusions: The results show that overexposure to noise and heat stress may be encountered during routine non-outage work activities in coal-fired power plants. Appropriate actions should be taken to reduce future health outcome from occupational exposure to noise and heat stress in the industry.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.591-597
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• 1998

Background: The aim of the current study was to analyze the early and intermediate-term performance of aortic valve replacement. Material and Method: Between January 1986 and January 1996, records of 61 consecutive patients who had received aortic valve replacement were reviewed. 38 were male and 23 were female patients, ranging from 10 to 71 years of age(mean: 40.5${\pm}$11.2). Results: The early death rate was 4.9%(3/61). A thorough follow-up rate of 93.1% was accomplished in these 58 patients who left the hospital(mean: 51.5${\pm}$32.0 patient-months) under the assistance of the same operator. Three of these patients who left the hospital died. The late death rate was 5.2%(3/58). Five patients experienced anticoagulant-related hemorrhage(all were minor). Three patients had thromboembolic episodes. There was no clinical evidence of hemolysis and structural failure of valves used. Of those patients who survived, the NYHA functional class improved significantly. Linearized rate were 1.58%/patient-year and 2.0%/patient-year respectively for thromboembolism and anticoagulant-related hemorrhage. The 10 year actuarial survival rate was 83.6%. Conclusion: This early and intermediate-term follow-up suggests that the mechanical valve is a reliable and durable prosthesis with good hemodynamic function and low rate of prosthesis-related complication.

• Journal of Drive and Control
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• v.12 no.4
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• pp.60-70
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• 2015

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements for farm work. However, when the tractor carries material using the bucket attached to the FEL on a sloping ground, the materials can spill or roll back over the operator due to the tilted body, thereby requiring the bucket surface to remain level at a constant value regardless of varying slopes. In this study, an active system for controlling the angle of the FEL bucket on a tractor based on the real-time measurement of ground slopes was developed to enable the bucket to constantly remain level. A FEL simulator operated based on an electro hydraulic proportional valve (EHPV) was constructed in the laboratory to develop a proportional-integral-derivative (PID) controller forming a virtual electronic control unit (ECU) on the computer, which could automatically adjust the bucket angles depending on varying input angles while sending SAE-J1939 associated messages via CAN BUS to the EHPV. The different parameter values for the PID controller due to the gravity effect of the bucket were determined using a manual PID tuning method while assuming that the tractor travels on either an ascending slope or a descending slope. The developed PID control-based self-leveling system showed a mean of steady-state errors of within $1^{\circ}$ and a mean of delayed times of ~ 0.8s when the step input of $+20^{\circ}$ was given, implying that the developed system and control algorithm would be effective in maintaining the bucket angle at a certain value. Future studies include the improvement of the control algorithm to reduce such a time delay as well as the application of the developed algorithm to the FEL mounted on a tractor tested at a testing ground.