• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.628-635
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• 1999

Background : Maximal expiratory flow rate is determined by the size of airway, elastic recoil pressure and the collapsibility of airway in the lung. The obstruction of expiratory flow is one of the major functional impairments of emphysema, which represents COPD. Nevertheless, expiratory narrowing of upper airway may be recruited as a mechanism for minimizing airway collapse, and maintaining lung volume and hyperinflation by an endogenous positive end-expiratory pressure in patients with airflow obstruction. We investigated the physiologic role of trachea in respiration in emphysema. Method : We included 20 patients diagnosed as emphysema by radiologic and physiologic criteria from January to August in 1997 at Seoul Municipal Boramae Hospital. Chest roentgenogram, high resolution computed tomography(HRCT), and pulmonary function tests including arterial blood gas analysis and body plethysmography were taken from each patient. Cross-sectional area of trachea was measured according to the respiratory cycle on the level of aortic arch by HRCT and calibrated with body surface area. We compared this corrected area with such parameters of pulmonary function tests as $PaCO_2$, $PaO_2$, airway resistance, lung compliance and so on. Results : Expiratory cross-sectional area of trachea had significant correlation with $PaCO_2$ (r=-0.61, p<0.05), $PaO_2$ (r=0.6, p<0.05), and minute ventilation (r=0.73, p<0.05), but inspiratory cross-sectional area did not (r=-0.22, p>0.05 with $PaCO_2$, r=0.26, p>0.05 with $PaO_2$, and r=0.44, p>0.05 with minute ventilation). Minute ventilation had significant correlation with tidal volume (r=0.45, p<0.05), but it had no significant correlation with respiratory frequency (r=-0.31, p>0.05). Cross-sectional area of trachea had no significant correlation with other parameters of pulmonary function including $FEV_1$, FVC, $FEV_1$/FVC, peak expiratory flow, residual volume, diffusing capacity, airway resistance, and lung compliance, whether the area was expiratory or inspiratory. Conclusion : Cross-sectional area of trachea narrowed during expiration in emphysema, and its expiratory area had significant correlation with $PaCO_2$, $PaO_2$, and minute ventilation.

• Journal of Hospice and Palliative Care
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• v.8 no.2
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• pp.152-155
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• 2005

Purpose: The lower extremity edema (LEE) is a common distressful symptom in advanced cancer patients and is hard to manage. We analyze the characteristics of LEE in patients with advanced cancer to provide the basic information of causes and adequate management. Methods: Physical examination, assessment of the location and severity of edema, blood chemistry (albumin, creatinine), Doppler Sono for patients with suspecting deep vein thrombosis (DVT), and abdomen CT scan for patient with suspecting lymph edema were performed. Severity of edema was classified according to NCI lymph edema scaling and improvement was defined as lowering at least 1 grade of edema after management. Results: Among 154 patient who had been admitted to Hospice Ward from Mar 2003 to Jan 2004, 33 had LEE, and 6 had both upper extremity edema and LEE except generalized edema. Their underlying cancers were stomach (7), lung (6), biliary tract (5), liver (5), colorectal (5), pancreas (2), and others (9). There were 12 patient with grade I, 20 patients with grade II, and 7 patients with grade III edema. The causes were hypoalbuminemia (11), lymph edema (10), DVT (7), obstruction of inferior vena cava (IVC) or portal vein (6), and dependent edema (5). The common managements were including leg elevation and diuretics. Elastic stocking was applied for patients with DVT and leg massage and pneumatic compression was used for lymph edema. The 2/3 patients were improved after management. Conclusion: The incidence of LEE in terminal cancer pts was high (25.3%) and their causes were variable including lymph edema, DVT, hypoalbuminemia and dependent edema. Active noninvasive management according to causes could result in good palliation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.111-112
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• 2009

Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.142-149
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• 2002

Low-viscosity composite resins may produce better sealed margins than stiffer compositions (KempScholte and Davidson, 1988: Crim, 1989). Plowable composites have been recommended for use in Class V cavities but it is also controversial because of its high rates of shrinkage. On the other hand, in the study comparing elastic moduli and leakage, the microfill had the least leakage (Rundle et at. 1997) Furthermore, in the 1996 survey of the Reality Editorial Team, microfills were the clear choice for abfraction lesions. The purpose of this study was to evaluate the microleakage of 6 compostite resins (2 hybrids, 2 microfills, and 2 flowable composites) with and without load cycling. Notch-shaped Class V cavities were prepared on buccal surface of 180 extracted human upper premolars on cementum margin. The teeth were randomly divided into non-load cycling group (group 1) and load cycling group (group 2) of 90 teeth each. The experimental teeth of each group were randomly divided into 6 subgroups of 15 samples. All preparations were etched, and Single bond was applied. Preparations were restored with the following materials (n=15) : hybrid composite resin [Z250(3M Dental Products Inc. St. Paul, USA), Denfil(Vericom, Ahnyang, Korea)], microfill [Heliomolar RO(Vivadent, Schaan, Liechtenstein), Micronew(Bisco Inc. Schaumburg, IL, USA)], and flowable composite［AeliteFlo(Bisco Inc. Schaumburg, IL, USA), Revolution(Kerr Corp. Orange, CA, USA)]. Teeth of group 2 were subjected to occlusal load (100N for 50,000 cycles) using chewing simulator(MTS 858 Mini Bionix II system, MTS Systems Corp. Minn. USA). All samples were coated with nail polish 1mm short of the restoration, placed in 2％ methylene blue for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a sclale of 0 (no leakage) to 3 (3/3 of wall). Results were statistically analyzed by Kruscal-Wallis One way analysis, Mann-Whitney U-test, and Student-Newmann-Keuls method. (p = 0.05) Results : 1. There was significantly less microleage in enamel margins than dentinal margins of all groups (p＜0.05) 2. There was no significant between six composite resin in enamel margin of group 1. 3. In dentin margin of group 1, flowable composite had more microleakage than others but not of significant differences. 4. there was no significant difference between six composite resin in enamel margin of group 2. 5. In dentin margin of group 2, the microleakage were R＞A =H=M＞D＞Z. But there was no significant differences. 6. In enamel margins, load cycling did not affect the marginal microleakage in significant degree. 7. In enamel margins, load cycling did affect the marginal microleakage only in Revolution. (p＜0.05).

• Journal of the Korean Institute of Navigation
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• v.4 no.2
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• pp.45-79
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• 1980

The aim of this paper is to analyze the mechanics of price formation in the tramp shipping. For the purpose of this study, the main characteristics of tramp freight rates and the market is examined, and a brief examination of the nature ofthe costs of operation is given which are essential for the understanding of the functioning of shipping firms as well as for the understanding of developments in the tramp freight market. The demand and supply relationships in the market is also analysed in detail. Tramp shipping is an industry that has a market which functions under conditions that are not dissimilar to the theoretical model of perfect competition. However, it does notmean that tramp shipping market is a perfectly competitive market. It is apparent that this realworld competitive system has its imperfections, which means that the market for tramp shipping is near to being a perfectly competitive market on an internaitonal scale and it is freight are therefore subjext to the laws of supply and demand. In theory, the minimum freight rate in the short term is that at which the lowest cost vessels will lay-up in preference to operating, and is equal to the variable costs minus lay-up costs; and this would imply that in all times except those of full employment for ships there is a tendency for newer low-cost, and, probably, faster vessels to be driving the older high-cost vessels in the breaker's yards. In this case, shipowners may be reluctant to lay-up their ships becasue of obligations to crews, or because they would lose credibility with shippers or financiers, or simply because of lost prestige. Mainly, however, the decision is made on strictly economic grounds. When, for example, the total operating costs minus the likely freight earnings are greater than the cost of taking the ship out of service, maintaining it, and recommissioning it, then a ship may be considered for laying-up; shipowners will, in other words, run the ships at freight earnings below operating costs by as much as the cost of laying them up. As described above, the freight rates fixed on the tramp shipping market are subject to the laws of supply and demand. In other words, the basic properties of supply and demand are of significance so far as price or rate fluctuations in the tramp freight market are concerned. In connection with the same of the demand for tramp shipping services, the following points should be brone in mind: (a) That the magnitude of demand for sea transport of dry cargoes in general and for tramp shipping services in particular is increasing in the long run. (b) That owning to external factors, the demand for tramp shipping services is capable of varying sharphy at a given going of time. (c) The demad for the industry's services tends to be price inelastic in the short run. On the other hand the demand for the services offered by the individual shipping firm tends as a rule to be infinitely price elastic. In the meantime, the properties of the supply of the tramp shipping facilities are that it cannot expand or contract in the short run. Also, that in the long run there is a time-lag between entrepreneurs' decision to expand their fleets and the actual time of delivery of the new vessels. Thus, supply is inelastic and not capable of responding to demand and price changes at a given period of time. In conclusion, it can be safely stated that short-run changes in freight rates are a direct result of variations in the magnitude of demand for tramp shipping facilities, whilest the average level of freight rates is brought down to relatively low levels over prolonged periods of time.

• 한국노년학
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• v.37 no.1
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• pp.237-250
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• 2017

The purpose of this study is to analyze the effects of exercise program for prevention of falling on physical fitness, posture and fall prevention self-efficacy for elderly women. 30 females above the age of 65 were subjects for this study. Over an twelve week period, 14women in the experimental group performed exercise 2 times a week for 60 minutes per session. 16women in the control group didn't participate in the exercise program. The independent variable was a exercise program for prevention of falling. Dependent variables were physical fitness, posture and fall prevention self-efficacy. Prevention of falling exercise program is consisted of an elastic band using exercise and Korean dance movement exercise. Physical fitness consisted of grip strength, upper and lower body endurance, cardiovascular endurance, flexibility, balance, coordination. The posture was measured the static posture when standing, using a high-resolution camera, body style to automatically measure the distance and angle(M-zen, Korea). Posture was measured in both the coronal and sagittal plane via reference board. Fall prevention self-efficacy was measured via questionnaire using the Korea Falls Self-Efficacy Scale (FES-K). The physical fitness, posture and fall prevention self-efficacy were measured twice with pre and post exercise, and the difference between groups with Wilcox signed rank test, and the group-specific post verification was carried out with U-validated methods (Mann Whitney U test). Statistical significance level was verified by setting the p<.05. Lower body endurance, cardiovascular endurance, flexibility, balance and coordination significantly increased in the experimental group. The control group was no significant increase in physical fitness variables. shoulder slope angle, pelvic slope angle(coronal/sagittal), leg length difference, scapular inferior angle and left/right calcaneus angle significantly decreased in the experimental group. Both the experimental group and control group were no significant increase in fall prevention self efficacy. The prevention of falling exercise program for elderly women indicated the positive changes in physical fitness(except grip strength) and posture(except upper body slope). However, there are no significant differences of falling prevention self-efficacy between the both group. Thus, the prevention of falling exercise program for the elderly has been proved that it is highly efficient on improving physical fitness and posture proofreading. However, we still need to consider supplement exercise for grip strength and upper body slope.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.629-636
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• 2021

The purpose of this study was to identify the effects of mammo pad made of different kinds of materials on the reduced inconvenience and compression pains of patients to examine plausible interchangeability of existing pads made of single kind of material, and to examine the changes in pains of patients taking mammography and various factors therein. The high-hardness and highly-elastic mammo pressure pads, capable of replacing existing mammo pad of "H" company, were manufactured, and the display quality of mammography obtained from respective mammo pad were compared to each other to appraise the availability of manufactured mammo pad. In addition, 200 patients, who came to a general hospital in Seoul, were selected as subjects for the survey employing a questionnaire which was distributed to the subjects from December 2018 to March 2020 to identify the factors involved with the mammo pad of patients while taking mammography. The results of mammography obtained from both of the existing and newly manufactured mammo pad revealed appropriate display qualities fell within the range of clinical criteria. Besides, the factors associated with changing compression pains of patients taking mammography were analyzed wherefrom the general factors in the following order of age, height, and BMI index appeared, while the experiential and female factors appeared as in the following order: presence of menstruation, experience of child-birth, experience of breast feeding, menopause, grade of breast, shape of breast, and experience of mammography. In conclusion, the following factors comprising the age, experience of breast feeding, experience of mammography, and menopause rendered approximately 54% of power of explaining the degree of changing pains during mammography. Regarding the changes in compression pains while taking mammography, the increasing experience of mammography of patients rendered approximately 0.26 times more at the intermediate range of compression pains and approximately 0.14 times more at the range of severe pains.