• BMB Reports
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• v.38 no.1
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• pp.115-119
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• 2005

Replacement of valine by tryptophan or tyrosine at position $\alpha$96 of the $\alpha$ chain ($\alpha$96Val), located in the ${\alpha}_1{\beta}_2$ subunit interface of hemoglobin leads to low oxygen affinity hemoglobin, and has been suggested to be due to the extra stability introduced by an aromatic amino acid at the $\alpha$96 position. The characteristic of aromatic amino acid substitution at the $\alpha$96 of hemoglobin has been further investigated by producing double mutant r Hb ($\alpha$42Tyr$\rightarrow$ Phe, $\alpha$96Val$\rightarrow$Trp). r Hb ($\alpha$42Tyr$\rightarrow$Phe) is known to exhibit almost no cooperativity in binding oxygen, and possesses high oxygen affinity due to the disruption of the hydrogen bond between $\alpha$42Tyr and $\beta$99Asp in the ${\alpha}_1{\beta}_2$ subunit interface of deoxy Hb A. The second mutation, $\alpha$96Val$\rightarrow$Trp, may compensate the functional defects of r Hb ($\alpha$42Tyr$\rightarrow$Phe), if the stability due to the introduction of trypophan at the $\alpha$96 position is strong enough to overcome the defect of r Hb ($\alpha$42Tyr$\rightarrow$Phe). Double mutant r Hb ($\alpha$42Tyr$\rightarrow$Phe, $\alpha$96Val$\rightarrow$Trp) exhibited almost no cooperativity in binding oxygen and possessed high oxygen affinity, similarly to that of r Hb ($\alpha$42Tyr$\rightarrow$Phe). $^1$H NMR spectroscopic data of r Hb ($\alpha$42Tyr$\rightarrow$Phe, $\alpha$96Val$\rightarrow$Trp) also showed a very unstable deoxy-quaternary structure. The present investigation has demonstrated that the presence of the crucible hydrogen bond between $\alpha$42Tyr and $\beta$99Asp is essential for the novel oxygen binding properties of deoxy Hb ($\alpha$96Val$\rightarrow$Trp).

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.153-170
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• 1977

Considering the ways for the possible improvement of soil test for upland crops, various methods for the evaluation of K supplying power and testing of available soil K were reviewed in terms of theoretical principles and practical usefulness of the each method. The review was also made on the characteristics of upland crops in K requirement and on the chemical properties of major korean upland and lowland rice soils in terms of K availability. Following is the few remarks drawn from the review. 1. Quite large number of methods have been known for the evaluation of K supplying power and testing for available soil K. In nature, they can be divided into two categories; capacity-based methods and intensity-based methcds. The capacity-based methods usually measure the exchangeable and some portion of nonexchangeable K, while the intensity-based methods suggest to consider the ractivity ratios of major cations in soil solution and the energy requirement for the replacement of exchangeable soil K into soil solution. 2. As methodology for extraction of interested part of soil K, chemical extraction, electrodialysis and ion exchange methods have been known. Among these, chemical extract ion is favorable because of its simplicity. However, recently suggested Electro-Ultra-Filtration method seems to merit further study for wider use for not only K but also other nutrient availability of soils. 3. The intensity-based methods, although they are more theoretical, because of their complexity, in methods may not be adapted for practical soil tests. 4. The exchangeable K which is rather simple to measure and which well reflects the status of K reserve as nonexchangeable and is immediate pool of water soluble K may be good, if not best, criterion of soil K availability to plant in common soil testing. 5. Because there are evidences that the abundance of available K alone may not be good inclication for availability of K to plant, it is recommendable to interprete the exchangeable K data as percent saturation of exchangeable K to total C. E. C. of soil for the recommend ation of K fertilizer based on soil tests. 6. Some pot and field trial results showed the trends that percent potassium saturation to total C. E. C. better serve as the parameter for K fertilizer recommendation.

• Journal of Chest Surgery
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• v.29 no.1
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• pp.24-31
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• 1996

Between January 1992 and February 1995, 36 patients with mitral regurgitation were treated by a mitral repair There wert nineteen men and seventeen women whose mean age was 41.8 years, ranged from 10 to 71. Seventeenth patients had dystrophic change of mitral valve, twelve patients had rheumatic change of mitral valve, second patients had infective change of mitral valve and another fifth patients had functional change of mitral valve. Operation proced res were suture annuloplasty (35 cases), resection of leaflet (25 cases), chordal shortening(9 cases) and commisurotomy(1 cases). These procedures were combined in most patients. Two third of the patients were in New York Heart Association class III or IV and four fifth of the patients were in mitral regurgitation grade III or IV by doppler echocardiogram. After mitral valve repair, the patients were improved hemodynamic, echocardiographic data and functional class. Intraoperative TEE had been used in all most patients after weaning of bypass. If there remained MR more than grade 2, the valve was re-repaired or replacement. There were no operative death. The late mortality was 5.5% and cause of death was congestive heart failure. Patients have been followed up from 3 to 40 months, mean 15. Second patients underwant reoperation due to recurred mitral regurgitation, 4 and 19 days after the operation. During reoperation, we found that the repair suture was disrupted in both patients. Th s expierence demonstrated that intraoperative TEE is accurate and predictable and excellent immediate and mid-term results have been achieved by mitral valve repair.

• Journal of Chest Surgery
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• v.37 no.6
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• pp.517-523
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• 2004

Background: The location of intimal tear can vary in type A acute aortic dissection. The aim of this study was to assess the operative result according to the intimal tear site. Material and Method: From January, 1995 to May, 2003, 18 patients underwent surgery for acute type A aortic dissection. The patients were classified according to the intimal tear site. In Group I (n=11), the intimal tear site was located within the ascending aorta, in Group II (n=7), the intimal tear site was located in the aortic arch, descending aorta, or intramural hematoma only. All clinical data were analyzed retrospectively. Result: In Group I, the operative time, cardiopulmonary bypass time, aorta cross clamp time and circulatory arrest time were 381.5$\pm$81.0 min, 223.5$\pm$42.5 min, 146.4$\pm$34.8 min and 36.5$\pm$17.4 min, respectively; and in group II, 461.7$\pm$54.0 min, 252.5$\pm$45.3 min, 162.5$\pm$45.3 min and 47.0$\pm$14.4 min respectively. All of those were greater in group II. The overall hospital mortality rate was 27.8% (5/18) and was significantly higher in Group II (57.1%)(p=0.003) compared to that in Group I (9.1%). The causes of death were hemorrhage (n=1) in group I and hemorrhage (n=2), multiple organ failure (n=1), and rupture of abdominal aorta (n=1) in group II. Conclusion: Surgical treatment of acute type A aortic dissection with intimal tear in the ascending aorta results in an acceptable mortality rate, but in patients with intimal tear in the aortic arch or descending aorta, the operative mortality still remains high when only ascending aorta replacement was performed. In these circumstances, in order to improve surgical results, efforts to include the intimal tear site in the operative procedure will be needed.

• Korean Journal of Psychosomatic Medicine
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• v.12 no.2
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• pp.145-156
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• 2004

Objectives : Internet addiction is a newly appeared addictive phenomenon that is defined as 'difficulty in real life due to internet over-use', 'excessive time spent on the internet or replacement of genuine real relationships with superficial virtual ones' or 'weakness in self-control about internet use and if discontinued, fallen in psychological confusion and anergic state'. This study was aimed to compare the internet addiction rate, demographic factors, computer using patterns, anxiety, depression, and internet self-efficacy and outcome expectancy between Korean middle and high school students in three areas - Seoul, Cheonan, and Rural areas - that were different in economic, cultural, and geographic state. Methods : Subjects are consisted of middle and high school students in Seoul, Chunan, and Rural areas(N=1718). Self-rating questionnaire included demographic data, Korean Spielberger State-Trait Anxiety Inventory, Korean Self-Rating Depression Scale(SDS), questions for internet-using pattern, Korean version of Internet Addiction Scale invented by K. S. Young, Internet Self-efficacy and Out-come Expectancy Scale. Results: In this study, prevalence of internet addiction was 2.9%. There was no significant difference found in prevalence of internet addiction among three areas. In all subjects, there were significant differences in anxiety, depression, internet self-efficacy and outcome expectancy, leisure style, places of internet use, internet connecting method, and insight on internee addiction. But, in addicted group, there was no significant difference among three areas. Conclusion: This study suggested that the difference in economic, cultural, and geographic state was not related to prevalence of internet addiction. Although there were significant differences in anxiety, depression, self-efficacy associated with internee use, leisure style, places of internet use, internet connecting method, insight on internet addiction among three areas, there were no significant difference in addicted group among three areas. So, we concluded that the difference in economic, cultural, and geographic state did not influence the prevalence of internet addiction, and despite the difference in economic, cultural, and geographic state, people in three areas were equally influenced by internet addiction.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.441-446
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• 2009

Background: Side clamping of ascending aorta during proximal graft anastomosis in coronary bypassing surgery in-creases the risk of direct aortic injury as well as embolization of intimal atheroma. Heartstring proximal sealing system (Guidant Corporation, Santa Clara, Calif), developed to avoid aortic side clamping, may minimize risks of such complications. The aim of the current study is to compare the surgical outcomes of the two proximal anastomosis techniquesi.e., Heartstring system versus aortic side clamping in off pump coronary bypassing' surgery (OPCAB). Material and Method: From January 2003 to August 2008, 499 patients underwent OPCAB. Of them, proximal graft anastomosis was performed using Heartstring system in 182 patients (Group I) and conventional manual anastomosis in 317 patients (Group II). The two groups were compared for postoperative major complications and mortality. Result: Two groups showed similar characteristics in terms of preoperative demographic data, left ventricular ejection fraction, renal function and history of diabetes, hypertension and smoking. Although there was no inter-group difference in the history of cerebral ischemia (p=0.48), preoperative brain magnetic resonance angiography revealed greater incidence of severe carotid artery stenosis (>75% of lumen) in the Group I than in the. Group II (44.5% in the Group I and 30.0% in the Group II, p=0.003). There were no inter-group differences in postoperative mortality (p=0.40) and complications (p=0.47) including neurologic events (3 in the Group land 2 in the Group II, p=0.258). Whereas neurologic events all comprised transient ischemic attacks in the Group I, they comprised multiple embolic strokes in the Group II. One patient in the Group II experienced aortic dissection during proximal anastomosis which resulted in ascending aortic replacement. Conclusion: Although proximal anastomosis using Heartstring system did not show statistically significant benefit over aortic side clamping, the. absence of embolic stroke maybe a definite benefit which may be better defined through further studies over a larger cohort.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.655-665
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• 2000

Taking account of the structural variation on species composition by topography, the successional trends were comparatively analyzed for the three topographic positions (valley, mid-slope, and ridge) in the natural deciduous forest of Mt. Chumbong area. The analysis was based upon the subsequent process of generation replacement by understory saplings and seedlings over the overstory trees which will be eventually fallen down. This study adopted the plot sampling method, establishing twenty $20m{\times}20m$ quadrats and collecting vegetation and site data on each different topographic position. The transition matrix model, which was modified from the mathematical theory of Markov chain, was employed to analyze the successional trends and thereafter to predict the overstory species composition in the future for each different topographic position. In valley, the simulation indicated the remarkable decrease in the proportion of species composition of present dominants Quercus mongolica and Fraxinus mandshurica from current 23% and 21% to around 4% of each at the steady state, which is predicted to take less than 200 years. On the other hand, the proportion of such species as Abies holophylla, Acer mono, Tilia amurensis, and Ulmus laciniata will increase at the steady state. In mid-slope, the result showed the remarkable decrease in the proportion of Juglans mandshurica, Kalopanax pictus, and Tilia amurensis from current 15%, 8%, and 15% to 2%, 1%, and 5%, respectively, at steady state predicted to take more than 250 years. In ridge, the current dominant Quercus mongolica was predicted to be decreased dramatically from 58% to 8% at steady state which could be achieved about 200 years. On the contrary, the proportion of Acer mono and Tilia amurensis will be increased from current 4% and 3% to more than 20% and 40%, respectively, at the steady state. Overall results suggested that the study forest is more likely seral rather than climax community. Even though a lot of variation is inevitable due to various kinds of site and vegetation development, the study forest is considered to be more than 200 years away from the steady state or climax in terms of overstory species composition.

• Korea journal of population studies
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• v.26 no.1
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• pp.31-57
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• 2003

This study is intended to examine (l)whether the value of son-for example, old age security and succession of family lineage- causing son preference in the traditional society can be explained at the individual level, (2)whether women without son in the son preference country continue her childbearing until having at least one son or give up the desire of having a son at a certain level. To accomplish these purposes, the 1974 Korean National Fertility Survey data are analyzed by the quadratic hazard models controlling unobserved heterogeneity. Unlike ordinary regression model, even omitted variables that affect hazard rates and are uncorrelated with the included independent variables can distort the parameter estimates in the hazard model. Therefore the nonparametric maximum likelihood estimator(NPMLE) of a mixing distribution developed by Heckman and Singer is used to control unobserved heterogeneity. Based on the statistical result in this study, the value of son causing son preference is determined at the societal level, not at the individual level. And Korean women without a son did not continue endlessly childbearing during child bearing ages until having a son. In general, they gave up the desire having a son when she had born six daughters continuously. Thus, 30-40 years ago, the number of daughters that women without a son giving up the desire of son was six, which is about the level of total fertility rate during 1960s. In these days, we can often see many women who have only two or three daughters and do not any son. This means that the level of giving up the desire of son, which is one factor representing the strength of son preference, becomes lower. If the strength of son preference did not become much weaker, then the fertility rates in Korea could not reach the below replacement level.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.833-838
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• 2004

Background: Despite the excellent early results after the repair of congenital bicuspid aortic valve (BAV) disease, the mid-term durability of the repaired valve has still controversies. Material and Method: To evaluate the mid-term results of BAV repair, retrospective review of medical records and echocardiographic data were done. Between 1994 and 2003, twenty-two patients underwent reparative procedure for either regurgitant or stenotic congenital bicuspid aortic valve (BAV). Result: Mean age was $41\pm14$ years with male predominance (Male=17, Female=5). The pathophysiologies of the BAV were regurgitation-dominant in 20 (91%) and stenosis-dominant in 2 (9%) cases. Various repair techniques were used for raphe, prolapsed leaflet, thickened leaflet, and commissures; 1) release of raphe in 19 (86%), 2) wedge resection and primary repair in 11 (50%), pericardial patch reinforcement after plication of the leaflet in 6 (27%), and plication of the leaflet in 3 (14%), 3) slicing of thickened leaflet was used in 12 (55%) cases, 4) commissuroplasty in 8 (36%), and commissurotomy in 6 (27%) cases. There was no in-hospital mortality. During the mean follow-up of $38\pm17$ months, one patient underwent aortic valve replacement after developing acute severe regurgitation from dehiscence of the suture on postoperative 2 months. New York Heart Association functional class was improved from $1.9\pm0.6$ to $1.2\pm0.5$ (p<0.01). Left ventricular end-systolic and diastolic dimension (LVESD/LVEDD) were also improved from $45\pm9$ and $67\pm10$ to $37\pm10$ and $56\pm10,$ respectively (p<0.01). The grade of aortic regurgitation (AR) was improved from preoperative $(3.1\pm1.2)$ to post-bypass $(0.9\pm0.7).$ However, the grade at last follow-up $(1.7\pm1.1)$ was deteriorated during the follow-up period (p<0.01). Freedom from grade III and more AR at one, three, and four year were 89.7%, 89.7%, and 39.9% respectively. Conclusion: Midterm clinical result of the BAV repair was favorable. But, the durability of the repaired valve was not satisfactory.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1865-1872
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• 2015

This study attempted to investigate consumer perceptions and attitudes towards reducing sugar intake by providing data to develop guidelines for the government and food-related industries to encourage Korean consumers to maintain appropriate levels of sugar intake. A survey was conducted on 238 adult consumers regarding their purchasing power for products with high sugar content in Seoul and Bundang, Gyeonggi area from September 1~30, 2013. Nutritional information on sugary products had a greater impact than media and others' recommendations on consumer awareness regarding need to reduce sugar intake. External factors such as health and weight control were stronger reasons for consuming reduced amounts of sugar or sugar-free products than internal factors such as sweetness. However, internal factors-such as taste-did not have a greater effect on consuming reduced amounts of sugar or sugar-free products than environmental factors-such as absence of purchase channels. Consumers indicated higher acceptance for 50% reduction in sweetness of existing commercial products. Regarding methods of lowering sugar intake, sugar replacement and reducing sugar consumption both generally and at home were preferred. In addition, consumers were likely to pay 10~14% more for sugar-reduced products than for existing products. Overall, consumers expressed positive attitudes towards reducing sugar intake in the future, although those in their twenties tended to be more passive than other age groups.