• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.1
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• pp.109-116
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• 2017

This paper describes the investigation into the durability alkali-activated materials(AAM) mortar and paste samples manufactured using fly-ash(FA) and ground granulated blast furnace slag(GGBFS) exposed to a sulfate environment with different GGBFS replace ratios(30, 50 and 100%), sodium silicate modules($Ms[SiO_2/Na_2O]$ 1.0, 1.5 and 2.0). The tests involved immersions into 10% sodium sulfate solution($Na_2SO_4$), 10% magnesium sulfate solution($MgSO_4$), 10% magnesium nitrate solution($Mg(NO_3)_2$) and 5% magnesium nitrate($Mg(NO_3)_2$+5% sodium sulfate solution+$Na_2SO_4$). The evolution of compressive strength, weight, length expansion and microstructural observation such as x-ray diffraction were studied. As a results, in case of immersed in $Na_2SO_4$, $Mg(NO_3)_2$ and $Mg(NO_3)_2+Na_2SO_4$ shows increase in long-term strength. However, for samples immersed in $MgSO_4$, the general observation was that the compressive strength decreased after immersion. The most drastic reduction of compressive strength and expansion of weight and length occurred when GGBFS or Ms ratios were higher. Also, the XRD analysis of samples immersed in magnesium sulfate indicated that expansion of AAM caused by gypsum($CaSO_4{\cdot}2H_2O$) and brucite(MgOH). The results showed that, an additional condition $Mg^{2+}$ in which ${SO_4}^{2-}$ is the presence of a certain concentration, sulfate erosion has to be accelerated.

• Journal of Chest Surgery
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• v.30 no.11
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• pp.1077-1082
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• 1997

To assess the early results, risk factors and optimal timing for coronary artery bypass graft surgery(CABG) after an acute myocardial infarction(AMI), we reviewed our 19 patients who underwent CABG within 30 days after AMI, between June 1994 and October 1996. This study excluded 1 patient whose diagnosis was AMI with ventricular septal rupture. 14 of the patients were male and 5 were female. Their ages ranged from 41 to 77 years(mean age, 60.6$\pm$ 10.4 years), and the amount of time between AMI and CABG ranged from 8 hours to 24 days(mean time, 10.6$\pm$6.4 days). There were 11 anteroseptal infarctions and 8 inferior wall infarctions. 11 patients had trsnsmural infarctions and 8 had subendocardial infarctions. Indications of operations were p imary revascularization and postinfarction angina. Three patients required preoperative intra-aortic balloon pump(IABP) support, and 4 additional patients required IABP to be separated from cardiopulmonary bypass. An average of 3.6 $\pm$ 0.6 vessels per patient were bypassed. The early mortality rate for these 19 patients was 5.3% and late mortality rate was 5.5%, 1-year and 2-year actuarial survival rates were 89.5% Univariate analysis of mortality showed that an ejection fraction less than 30% and intraopretative IABP supports were associated with risk factors(p value=0.018 and 0.015 respectively). Age, sex, time to CABG, emergency operations, types and locations of infarctions were not significant. Although our studies have weak p.oints in that there was only a small number of patients and the lack of long-term results, we could conclude that early myocardial revascularization is relatively safe after AMI for those individuals with an ejection fraction greater than 30%.

• Management & Information Systems Review
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• v.34 no.3
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• pp.17-39
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• 2015

This study examined the structural changes and volatility in the global stock markets using a Markov Regime Switching ARCH model developed by the Hamilton and Susmel (1994). Firstly, the US, Italy and Ireland showed that variance in the high volatility regime was more than five times that in the low volatility, while Korea, Russia, India, and Greece exhibited that variance in the high volatility regime was increased more than eight times that in the low. On average, a jump from regime 1 to regime 2 implied roughly three times increased in risk, while the risk during regime 3 was up to almost thirteen times than during regime 1 over the study period. And Korea, the US, India, Italy showed ARCH(1) and ARCH(2) effects, leverage and asymmetric effects. Secondly, 278 days were estimated in the persistence of low volatility regime, indicating that the mean transition probability between volatilities exhibited the highest long-term persistence in Korea. Thirdly, the coefficients appeared to be unstable structural changes and volatility for the stock markets in Chow tests during the Asian, Global and European financial crisis. In addition, 1-Step prediction error tests showed that stock markets were unstable during the Asian crisis of 1997-1998 except for Russia, and the Global crisis of 2007-2008 except for Korea and the European crisis of 2010-2011 except for Korea, the US, Russia and India. N-Step tests exhibited that most of stock markets were unstable during the Asian and Global crisis. There was little change in the Asian crisis in CUSUM tests, while stock markets were stable until the late 2000s except for some countries. Also there were stable and unstable stock markets mixed across countries in CUSUMSQ test during the crises. Fourthly, I confirmed a close relevance of the volatility between Korea and other countries in the stock markets through the likelihood ratio tests. Accordingly, I have identified the episode or events that generated the high volatility in the stock markets for the financial crisis, and for all seven stock markets the significant switch between the volatility regimes implied a considerable change in the market risk. It appeared that the high stock market volatility was related with business recession at the beginning in 1990s. By closely examining the history of political and economical events in the global countries, I found that the results of Lamoureux and Lastrapes (1990) were consistent with those of this paper, indicating there were the structural changes and volatility during the crises and specificly every high volatility regime in SWARCH-L(3,2) student t-model was accompanied by some important policy changes or financial crises in countries or other critical events in the international economy. The sophisticated nonlinear models are needed to further analysis.

• Clinical and Experimental Pediatrics
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• v.45 no.5
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• pp.646-653
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• 2002

Purpose : The incidence of type 2 diabetes mellitus in children has been increasing worldwide recently, which is thought to be related to the increasing prevalence of obesity. We investigated to evaluate the incidence and the characteristics of type 2 diabetes mellitus in children and also analysed the relationship between intrauterine growth retardation and type 2 diabetes mellitus. Methods : We investigated 25 children diagnosed as type 2 diabetes mellitus between March 1990 and December 2000. The analysis was performed retrospectively with medical records based on the clinical characteristics and laborotory findings. Results : Incidence of type 1 and type 2 diabetes mellitus in children has been increasing since 1990. We demonstrated an increase in the percentage of type 2 diabetes mellitus children from 5.3% in 1990 to 21.0% in 2000. Sixty eight percent of patients(17/25) were classified as obese group. Initial symptoms at first visit were polyuria, polydipsia and polyphagia 48%(12/25), asymptomatic glycosuria 40% (10/25), weight loss 8%(2/25) and obesity 4%(1/25). The mean age at diagnosis was $12.9{\pm}1.8$ years. 64%(16/25) of patients had positive family history of type 2 diabetes mellitus. Autoanti-bodies were positive in 18.1%(4/22) of patients. Twenty eight percent (7/25) of patients had an associated disease and two patients had fatty liver in association with obesity. Treatment consisted of diet, exercise, education and oral hypoglycemic agents. Three patients were treated with insulin as well as oral hypoglycemic agents because of poor blood glucose control. Long-term diabetic complications occurred in 4 patients. Intrauterine growth retardtion was found in 34.6%(9/25); 88.9% (8/9) of these patients were non-obese group. Conclusion : The increase in the incidence of type 2 diabetes mellitus in children is thought to be related to the increasing prevalence of obesity. The non-obese group of patients might be associated with intrauterine growth retardation.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.364-372
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• 2010

Purpose : Good adherence of caregivers is essential for successful health outcomes in the treatment of childhood asthma. The purpose of this study was to identify the factors contributing to good adherence of maintenance treatment in children with well-controlled asthma. Methods : Children with well-controlled asthma being treated with a daily controller for at least 3 months in Korea University Anam Hospital were selected. Their caregivers who had good adherence to maintenance treatment were recruited. Qualitative study through in-depth interviews was conducted with 18 caregivers who agreed to the study. Results : The 18 caregivers (mean age, 40.0 years) consisted of 15 mothers, 2 grandmothers, and 1 father. The resulting consensus were identified and grouped into 2 domains: the caregiver/patient aspect with 8 theme factors and the treatment aspect with 4 theme factors. The main theme factors in the caregiver/patient aspect were enabling participation in physical activities and exercise (77.8%), perceptions regarding asthma and the need for long-term treatment (50.0%), and perceived value of the medications outweighing the risk of side effects (38.9%). The main theme factors in the treatment aspect were trust in the physician (77.8%), general satisfaction with the manner and attitude of the physician (77.8%) and verification of the necessity of further treatment by performing tests (38.9%). Conclusion : Efforts to improve caregivers' adherence to the treatment of childhood asthma must include a range of factors related to both caregiver/patient aspects and treatment aspects. Among all of these factors, it may be most important to establish a physician-caregiver partnership.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.1-8
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• 2007

Purpose: There has been increased the number of early gastric cancer and laparoscopy-assisted gastrectomy (LAG), due to early detection through mass screening program. We started the LAG in April 2004 and performed 119 cases of gastric cancer in 2005, so we report a surgical outcome compared with that of open gastrectomy (OG). Materials and Methods: 119 patients underwent LAG in 2005, and for open group, 126 patiens of early gastric cancer were selected sequentially from January 2005 to March 2005. We compared clinicopathologic characteristics, postoperative courses and complications between two groups. Results: There was no significant difference between age, a length of hospital stay, distal resection margin and a number of retrived lymph nodes. The operation time was longer in LAG group (239.2 vs 123.3 mins, P<0.001) and a diet progression was faster in LAG group (first flatus: 3.05 vs 3.70 days, SOW: 2.86 vs 3.22 days, liquid diet: 3.87 vs 4.19 days, soft diet: 4.84 vs 5.26 days, P<0.001). But there was no difference statistically in postoperative discharge date (7.73 vs 8.25 days, P=0.229). The additional requirement of analgesic injection was less frequent in LAG group (2.97 vs 4.92 times, P<0.001). The harvested lymph nodes were similar in both groups (23.9 vs 23.1, P=0.563). A complication rate was lower in LAG group (4.9% vs 9.5%), but there was no statistical significance (P=0.179). There was no mortality in both groups and no conversion to open gastrectomy in the LAG group. Conclusion: LAG can be performed safely and accepted in view of curative procedure in treatment of early gastric cancer. But we need the follow up of long-term period to evaluate the survival rate and recurrence, and a prospective randomized controlled study should be done to establish that LAG will be a standard operation for early gastric cancer.

• Sleep Medicine and Psychophysiology
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• v.6 no.1
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• pp.38-45
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• 1999

Objectives: We explored the characteristics of physiological variables such as electrodermal response(EDR) and electromyography(EMG) in patients with insomnia, panic disorder, and other anxiety disorders. we aimed to decide the minimum sessions in biofeedback treatment to make the treatment effective and examine the effects of long-term biofeedback treatment by measuring the physiological variables. Methods: Thirty seven outpatients who received biofeedback treatment were divided into 3 groups according to the number of biofeedback sessions(patients who received 4-5 sessions, who received 6-9 sessions, and who received more than 10 sessions). We measured mean and delta values of EDR and EMG levels, and the Hamilton Anxiety Rating Scale(HARS), and Slef-Relaxation Inventory(SRI) in all patients. Data were analyzed by t-test and repeated measures analysis of variance. Results: The mean and delta values of EDR and EMG levels were not different among the 3 groups during the first 4 biofeedback sessions. However, patients who received more than 10 biofeedback sessions had higher baseline mean EDR value(F=2.233, p=0.036) in the first session, compared with other patients. In patients who received more than 10 biofeedback sessions, mean EDR was significantly reduced after $5^{th}$ session(F=10.41, p<0.01). They showed significant improvement in SRI scores at 12th biofeedback session(t=2.726, p<0.05) and in HARS scores at $6^{th}$(t=3.10, p<0.05) and $12^{th}$ biofeedback session(t=10.93, p<0.001). Conclusions: Wesuggest that patients should receive more than 5 biofeedback sessions to experience internal cues and get a good clinical response to biofeedback treatment.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.585-593
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• 2000

Background : International consensus guidelines have recently been developed to improve the assessment and management of asthma. One of the major recommendation of these guidelines is that asthma severity should be assessed through the recognition of key symptoms, such as nocturnal waking, medication requirements, and objective measurements of lung function. Differential classification of asthma severity would lead to major differences in both long term pharmacological management and the treatment of severe exacerbation. Methods : This study examined the relationship between the symptom score and measurements of $FEV_1$ and PEF when expressed as a percentage of predicted values in asthmatics (n=107). Results : The correlation of $FEV_1$ % with PEFR% was highly significant (r=0.83, p<0.01). However, there was agreement in terms of the classification of asthma severity in 76.6% of the paired measurements of $FEV_1$ % and PEFR%. Agreement in the classification of asthma severity was also found in 57.1% of the paired analysis of $FEV_1$ % and symptom score. 39% of the patients classified as having moderate asthma on the basis of $FEV_1$ % recording would be considered to have severe asthma if symptom score alone were used. Low baseline $FEV_1$ and high bronchial responsiveness were associated with a low degree of perception of airway obstruction. Conclusion : The relationships between the symptom score, PEFR and $FEV_1$ were generally poor. When assessing asthma severity, age, duration, $PC_{20}$, and baseline $FEV_1$ should be considered.

• Journal of dental hygiene science
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• v.11 no.6
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• pp.573-581
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• 2011

The purpose of this study was to examine the professionalism of dental hygienists in dental institutions and the influential factors for their professionalism in an attempt to seek ways of enhancing the professionalism of dental hygienists. The subjects in this study were 172 dental hygienists who worked in dental institutions in Busan and Gimhae. A self-administered survey was conducted to gather data, and an experimental analysis was carried out to analyze the collected data. The major findings of the study were as follows: First, concerning professionalism, self-regulation belief(3.70) ranked highest(3.42), followed by service belief(3.65), autonomy belief(3.31), a sense of vocational calling(3.30) and utilization of the professional organization as a standard(3.12). Second, the professionalism of the dental hygienists was significantly better when their title was higher, when they were older, when they got a larger monthly pay and when they intended to work for a longer time. Third, as for the influential factors for their professionalism, age, marital status, the estimated term of working at the workplace and opinion on reemployment were also identified as the significant variables that were up to the standard level of significance(p=0.05). The findings of the study suggest that in order to boost the professionalism of dental hygienists, it's required to take institutional measures to give them more responsibility, autonomy and authority, and how to improve personnel administration by providing strong motivation for them to look at their workplaces more favorably and keep on working for a long time should discreetly be considered.