• The korean journal of orthodontics
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• v.49 no.3
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• pp.188-193
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• 2019

Objective: The aim of this finite element study was to clarify the mechanics of tooth movement in palatal en-masse retraction of segmented maxillary anterior teeth by using anchor screws and lever arms. Methods: A three-dimensional finite element method was used to simulate overall orthodontic tooth movements. The line of action of the force was varied by changing both the lever arm height and anchor screw position. Results: When the line of action of the force passed through the center of resistance (CR), the anterior teeth showed translation. However, when the line of action was not perpendicular to the long axis of the anterior teeth, the anterior teeth moved bodily with an unexpected intrusion even though the force was transmitted horizontally. To move the anterior teeth bodily without intrusion and extrusion, a downward force passing through the CR was necessary. When the line of action of the force passed apical to the CR, the anterior teeth tipped counterclockwise during retraction, and when the line of action of the force passed coronal to the CR, the anterior teeth tipped clockwise during retraction. Conclusions: The movement pattern of the anterior teeth changed depending on the combination of lever arm height and anchor screw position. However, this pattern may be unpredictable in clinical settings because the movement direction is not always equal to the force direction.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.169-176
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• 2019

Wireless sensor networks are used to monitor and control areas in a variety of military and civilian areas such as battlefield surveillance, intrusion detection, disaster recovery, biological detection, and environmental monitoring. Since the sensor nodes are randomly placed in the area of interest, separation of the sensor network area may occur due to environmental obstacles or a sensor may not exist in some areas. Also, in the situation where the sensor node is placed in a non-relocatable place, some node may exhaust energy or physical hole of the sensor node may cause coverage hole. Coverage holes can affect the performance of the entire sensor network, such as reducing data reliability, changing network topologies, disconnecting data links, and degrading transmission load. It is possible to solve the problem that occurs in the coverage hole by finding a coverage hole in the sensor network and further arranging a new sensor node in the detected coverage hole. The existing coverage hole detection technique is based on the location of the sensor node, but it is inefficient to mount the GPS on the sensor node having limited resources, and performing other location information processing causes a lot of message transmission overhead. In this paper, we propose an Adjacent Matrix-based Hole Coverage Discovery(AMHCD) scheme based on connectivity of neighboring nodes. The method searches for whether the connectivity of the neighboring nodes constitutes a closed shape based on the adjacent matrix, and determines whether the node is an internal node or a boundary node. Therefore, the message overhead for the location information strokes does not occur and can be applied irrespective of the position information error.

• Tuberculosis and Respiratory Diseases
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• v.82 no.1
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• pp.35-41
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• 2019

Background: Pulmonary tuberculosis can result in anatomical sequelae, and cause airflow limitation. However, there are no treatment guidelines for patients with a tuberculosis-destroyed lung. Recently, indacaterol effectiveness in chronic obstructive pulmonary disease (COPD) patients with Tuberculosis history (INFINITY) study revealed indacaterol provided bronchodilation and symptom improvement in COPD patients with a tuberculosis-destroyed lung. Methods: We conducted a post-hoc subgroup analysis of the randomized controlled trial, the INFINITY study, to determine factors associated with indacaterol response in a tuberculosis-destroyed lung with airflow limitation. Data from 68 patients treated with inhaled indacaterol, were extracted and analyzed. Factors associated with the response of forced expiratory volume in one second ($FEV_1$) to indacaterol treatment, were determined using linear regression analysis. Results: Of 62 patients included, 68% were male, and 52% had history of cigarette smoking. Patients revealed mean $FEV_1$ of 50.5% of predicted value with mean improvement of 81.3 mL in $FEV_1$ after indacaterol treatment for 8 weeks. Linear regression analysis revealed factors associated with response of $FEV_1$ to indacaterol included a short duration of smoking history, and high short-acting bronchodilator response. When patients with history of smoking were excluded, factors associated with response of $FEV_1$ to indacaterol included high short-acting bronchodilator response, and poor health-related quality of life score as measured by St. George's Respiratory Questionnaire for COPD. Conclusion: In a tuberculosis-destroyed lung with airflow limitation, short-acting bronchodilator response and smoking history can play a critical role in predicting outcomes of indacaterol treatment.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1115-1122
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• 2018

Purpose: To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. Materials and Methods: In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. Results: This study included 217 eyes of 118 participants (20-81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participant's age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20-44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased CorvisIOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20-44 years, and over 44 years). Conclusion: We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.4
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• pp.25-34
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• 2021

Objectives This study was conducted to evaluate the therapeutic effect of acupuncture after rotator cuff surgery. Methods Key words such as rotator cuff surgery and acupuncture were searched in 10 databases (Ovid-Medline, Ovid-EMBASE, Ovid-AMED, Cochrane Library, China National Knowledge Infrastructure [CNKI], National Digital Science Library [NDSL], Koreanstudies Information Service System [KISS], Oriental medicine Advanced Searching Integrated System [OASIS], KoreaMed, KMBASE), and only suitable randomized controlled trials (RCTs) were selected. Results 6 RCTs were finally selected, and acupuncture showed positive results for pain relief and functional recovery after rotator cuff surgery. However, the analyzed 6 RCTs showed a high overall risk of bias. Conclusions In the future, RCTs with a higher level of evidence on the effect of acupuncture after rotator cuff surgery need to be continuously conducted.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.4
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• pp.35-47
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• 2021

Objectives This study was conducted to evaluate the therapeutic effect of herbal medicine after total knee arthroplasty. Methods Key words such as total knee arthroplasty and herbal medicine were searched in 10 databases (Ovid-Medline, Ovid-EMBASE, Ovid-AMED, Cochrane Library, China National Knowledge Infrastructure [CNKI], National Digital Science Library [NDSL], Koreanstudies Information Service System [KISS], Oriental medicine Advanced Searching Integrated System [OASIS], KoreaMed, KMBASE), and only suitable randomized controlled trials (RCTs) were selected. Results 8 RCTs were finally selected, and herbal medicine showed positive results for pain relief and functional recovery after total knee arthroplasty. However, the analyzed 8 RCTs showed a high overall risk of bias. Conclusions In the future, RCTs with a higher level of evidence on the effect of herbal medicine after total knee arthroplasty need to be continuously conducted.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.11-18
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• 2021

Purpose : The purpose of this study was to investigate the effect on lung capacity of healthy men and women in their twenties by performing an intervention using the chest extension exercise and the bridge exercise, which are respiratory muscle strengthening exercises. Methods : Thirty adult men and women in their 20s participated in this study. All subjects participated in the study after hearing the explanation of the purpose and method of the study, filling out a consent form. All subjects were randomly assigned to the chest extension exercise (CEE) group and the bridge exercise (BE) group of fifteen each. Each exercise was performed twice a week for 4 weeks. Lung capacity was measured by forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) using spirometry. Lung capacity was measured before and after exercise. The measured data were compared through the dependent t-test and the independent t-test. The statistical significance level was set at .05. Results : After the intervention, the CEE group showed a significant increase in FVC and FEV₁ compared to before the intervention (p<.05). After the intervention, the BE group also had a significant increase in FVC and FEV₁ compared to before the intervention (p<.05). However, there was no difference in FVC and FEV₁ between groups before and after the intervention (p>.05). Conclusion : There was no difference between groups in lung capacity after exercise. However, both the chest extension exercise and the bridge exercise increased FVC and FEV1, which was thought to be because both exercise methods were effective in increasing lung capacity. Therefore, both chest extension exercises and bridge exercises can be effectively applied as a way to increase lung capacity.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.94-104
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• 2021

Objectives: A number of medical institutions have been conducting fit tests to perform seal checks on masks. This study aimed to compare the differences fit factor before and after domestic N95 mask-wearing training through a fit-test. Methods: A survey of 59 healthcare workers was conducted regarding whether they had undergone a fit test or received training on mask-wearing. Further, the fit of two types of domestic N95 masks was measured before and after the training using a QNFT(Quantitative Fit test). The average fit factors before and after training were compared using a paired t-test. Additionally the differences in the fit test pass rate were analyzed using a McNemar test. Results: A statistically significant difference was seen between the fit factors in the fit tests conducted before and after the training (p=0.0015), as well as in the fit of the two types of masks tested (p<0.01). Thus, an improvement in mask fitting was seen after the training, even with differently fitted masks. Conclusions: Upon using a QNFT, a significant increase in the fit factors for N95 masks was observed after training compared with masks that were fitted as usual. This highlights the importance of training in mask-wearing, with the conclusion that training healthcare providers will improve the fit of masks.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.167-174
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• 2021

Objective: Single leg bridge exercise (SLBE) improves trunk muscle activation and provides muscle stability by aligning joints related to posture. This preliminary study aimed to investigate the effects of SLBE on abdominal muscle activation in subacute stroke patients. Design: Cross-sectional study. Methods: Fifteen subacute stroke patients (9 males, 6 females) voluntarily participated in this study. SLBE was performed on the affected side. Each individual patient performed an SLBE ten times in three sets and was asked to hold their position for 5 s. Muscles activity was recorded using a surface electromyography (EMG) system before and after the SLBE. A surface EMG system was used to analyze the muscle activity during general bridge exercise, including the rectus abdominis (RA), internal oblique (IO), and external oblique (EO) abdominal muscles. Results: Muscle activity of both EO and IO on the affected side significantly increased (p<0.05), whereas the muscle activity of the RA and the three muscles on the unaffected side did not show a significant difference. In addition, improvement in muscle asymmetry of the EO and IO showed a significant change after SLBE (p<0.05). Conclusions: SLBE is effective in activating the abdominal muscles of stroke patients on the affected side and is a helpful exercise intervention that activates the muscles to transform asymmetric abdominal muscles into symmetric patterns.

• Safety and Health at Work
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• v.12 no.2
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• pp.225-229
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• 2021

Background: The socioeconomic burden of musculoskeletal disorders (MSDs) is significant, and kitchen work is a high-risk occupation for MSDs due to the intensive manual workload and repetitive movements that are involved. However, there are very few studies on MSDs and rest breaks as a workplace intervention among kitchen workers. This study examined the relationship between insufficient rest breaks and increased MSD risk among Korean kitchen workers. Methods: Sociodemographic and occupational factors of 1,909 kitchen workers were collected from the 3rd-4th Korean Working Conditions Survey data. Five items on rest breaks at work were categorized into two groups, "sufficient" and "insufficient." The number of MSDs and work-related MSDs (WMSDs), an outcome variable, was obtained from the sum of MSDs/WMSDs in three anatomical sites (back, neck, and upper limb, lower limb). The association between rest breaks and MSDs was estimated using zeroinflated negative binomial analyses, with adjustments for age, education level, and weekly working hours, and the analyses were stratified by sex. Results: After adjustment, significant associations were found between insufficient rest breaks and an increased risk of MSDs (odds ratio [OR] 1.68 95% confidence interval [CI] 1.11-2.54) and WMSDs (OR 1.40 95% CI 1.01-1.96) among female kitchen workers. Insufficient rest breaks were significantly associated with MSDs in female kitchen workers in all three anatomical sites. Conclusion: This study emphasizes the need for rest breaks as a workplace intervention for preventing MSDs in kitchen workers. Further studies to reveal the causality of this relationship are required.