• Journal of Chest Surgery
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• v.51 no.2
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• pp.100-108
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• 2018

Background: The question of which type of prosthetic aortic valve leads to the best outcomes in patients in their 60s remains controversial. We examined the hemodynamic and clinical outcomes of aortic valve replacement in sexagenarians according to the type of prosthesis. Methods: We retrospectively reviewed 270 patients in their 60s who underwent first-time aortic valve replacement from 1995 to 2011. Early and late mortality, major adverse valve-related events, anticoagulation-related events, and hemodynamic outcomes were assessed. The mean follow-up duration was $58.7{\pm}44.0$ months. Results: Of the 270 patients, 93 had a mechanical prosthesis (mechanical group), and 177 had a bioprosthesis (tissue group). The tissue group had a higher mean age and prevalence of preoperative stroke than the mechanical group. The groups had no differences in the aortic valve mean pressure gradient (AVMPG) or the left ventricular mass index (LVMI) at 5 years after surgery. In a sub-analysis limited to prostheses in the supra-annular position, the AVMPG was higher in the tissue group, but the LVMI was still not significantly different. There was no early mortality. The 10-year survival rate was 83% in the mechanical group and 90% in the tissue group. The type of aortic prosthesis did not influence overall mortality, cardiac mortality, or major adverse valve-related events. Anticoagulation-related events were more common in the mechanical group than in the tissue group (p=0.034; hazard ratio, 4.100; 95% confidence interval, 1.111-15.132). Conclusion: The type of aortic prosthesis was not associated with hemodynamic or clinical outcomes, except for anticoagulation-related events.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.487-498
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• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.449-460
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• 2014

Since the emergence of domestically produced automobiles in 1964, the number of automobiles in circulation in South Korea has increased constantly. With this rapidly increasing number of automobiles, automobile-induced environmental pollution has become an issue of great concern, especially with regard to air pollution. Of the carbon composites contained in automobile exhaust gas, PAHs are known to be carcinogenic and highly deleterious to humans and thus need to be urgently mitigated. To address this issue of PAHs, this study was conducted to estimate qualitative of particulate PAHs contained in carbon composites in automobile exhaust gas, by capturing all particulate matter discharged from the latter. To allow for differentiated analyses, the automobiles investigated were divided into 4 groups: gasoline vehicle, motocycle, diesel vehicle, and LPG vehicle. Samples were analyzed using two methods. First, in-depth analysis was performed on organic carbon (OC) and elemental carbon (EC) composites with analysis parameters, using the Thermal Optical Transmittance Method (NIOSH 5040). Second, for the examination of particulate PAHs, GC/MSD was used to analyze the 16 PAH species specified by the Environmental Protection Agency (EPA). The analyses yielded the findings that diesel vehicles had the highest mass concentration ($2,007{\mu}g/m^3$), followed by motocycle ($1,066{\mu}g/m^3$), LPG vehicle ($392{\mu}g/m^3$), and gasoline vehicles ($270{\mu}g/m^3$). The highest carbon concentrations in total particulate matter by vehicle weight were produced from LPG vehicle (79.8%), followed by gasoline vehicle (77.4%), motocycle (69.8%), and diesel vehicle (59.1%).

• Journal of Chest Surgery
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• v.48 no.3
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• pp.164-173
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• 2015

Background: Hypertrophied myocardium is especially vulnerable to ischemic injury. This study aimed to compare the early and late clinical outcomes of three different methods of myocardial protection in patients with aortic stenosis. Methods: This retrospective study included 225 consecutive patients (mean age, 65{\pm}10 years; 123 males) with severe aortic stenosis who underwent aortic valve replacement. Patients were excluded if they had coronary artery disease, an ejection fraction <50%, more than mild aortic regurgitation, or endocarditis. The patients were divided into three groups: group A, which was treated with antegrade and retrograde cold blood cardioplegia; group B, which was treated with antegrade crystalloid cardioplegia using histidine-tryptophan-ketoglutarate (HTK) solution; and group C, treated with retrograde cold blood cardioplegia. Results: Group A contained 70 patients (31.1%), group B contained 74 patients (32.9%), and group C contained 81 patients (36%). The three groups showed significant differences with regard to the proportion of patients with a New York Heart Association functional classification ${\geq}III$ (p=0.035), N-terminal pro-brain natriuretic peptide levels (p=0.042), ejection fraction (p=0.035), left ventricular dimensions (p<0.001), left ventricular mass index (p<0.001), and right ventricular systolic pressure (p <0.001). Differences in cardiopulmonary bypass time (p=0.532) and aortic cross-clamp time (p=0.48) among the three groups were not statistically significant. During postoperative recovery, no significant differences were found regarding the use of inotropes (p=0.328), mechanical support (n=0), arrhythmias (atrial fibrillation, p=0.347; non-sustained ventricular tachycardia, p=0.1), and ventilator support time (p=0.162). No operative mortality occurred. Similarly, no significant differences were found in long-term outcomes. Conclusion: Although the three groups showed some significant differences with regard to patient characteristics, both antegrade crystalloid cardioplegia with HTK solution and retrograde cold blood cardioplegia led to early and late clinical results similar to those achieved with combined antegrade and retrograde cold blood cardioplegia.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.151-161
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• 2012

An intensive analysis of 148 timings of V700 Cyg was performed, including our new timings and 59 timings calculated from the super wide angle search for planets (SWASP) observations, and the dynamical evidence of the W UMa W subtype binary was examined. It was found that the orbital period of the system has varied over approximately $66^y$ in two complicated cyclical components superposed on a weak upward parabolic path. The orbital period secularly increased at a rate of $+8.7({\pm}3.4){\times}10^{-9}$ day/year, which is one order of magnitude lower than those obtained by previous investigators. The small secular period increase is interpreted as a combination of both angular momentum loss (due to magnetic braking) and mass-transfer from the less massive component to the more massive component. One cyclical component had a $20.^y3$ period with an amplitude of $0.^d0037$, and the other had a $62.^y8$ period with an amplitude of $0.^d0258$. The components had an approximate 1:3 relation between their periods and a 1:7 ratio between their amplitudes. Two plausible mechanisms (i.e., the light-time effects [LTEs] caused by the presence of additional bodies and the Applegate model) were considered as possible explanations for the cyclical components. Based on the LTE interpretation, the minimum masses of 0.29 $M_{\odot}$ for the shorter period and 0.50 $M_{\odot}$ for the longer one were calculated. The total light contributions were within 5%, which was in agreement with the 3% third-light obtained from the light curve synthesis performed by Yang & Dai (2009). The Applegate model parameters show that the root mean square luminosity variations (relative to the luminosities of the eclipsing components) are 3 times smaller than the nominal value (${\Delta}L/L_{p,s}{\approx}0.1$), indicating that the variations are hardly detectable from the light curves. Presently, the LTE interpretation (due to the third and fourth stars) is preferred as the possible cause of the two cycling period changes. A possible evolutionary implication for the V700 Cyg system is discussed.

• Korean journal of applied entomology
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• v.43 no.1
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• pp.7-14
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• 2004

This study was carried out to survey and confirm the occurring sites of Parnassius bremeri in Korea, and to investigate ecological characteristics to develop a mass rearing technique. In the field survey, adults were found in the two previously known sites in Gyungnam Province and another site was newly found in Samcheok, Gangwon Province. Emergence period of adults was from middle of May to middle of June. Oviposition took place on various material, including hostplant, debris, dead leaves, etc. Eggs were laid singly, up to 126.7 eggs per female. The egg-period was 221.3${\pm}$2.3 days, eggs were hatched from 11th to 22nd of January in the natural condition, and started to feed for about 10 days after hatching. Survival rate of the 1st larvae was 67.6%. Developing period of each instar in the insectary (25$^{\circ}C$, 75% RH, 16L:8D) was 11.2 days for the 1st instar, 7.3 days for 2nd, 12.8 days for 3rd, 16.2 days for 4th, and 18.2 days for 5th, and the pupal period was 21.3 days. The average longevity of adults was 26.2 days. Oviposition rate was higher in the natural condition with enough space to fly for 3♀ : 1 ♂ coupled, at least 3 ${\times}$ 3${\times}$4 m-sized room, than in smaller cage. In a comparison of the preference for visiting on sugar source, black sugar and fructose were effective.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.149-156
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• 2016

It has been well known that concrete structures exposed to chloride and sulfate attack environments lead to significant deterioration in their durability due to chloride ion and sulfate ion attack. The purpose of this experimental research is to evaluate the long-term durability against chloride ion and sulfate attack of the alkali activated cementless concrete replacing the cement with ground granulated blast furnace slag. For this purpose, the cementless concrete specimens were made for water-binder ratios of 40%, 45%, and 50%, respectively and then this specimens were cured in the water of $20{\pm}3^{\circ}C$ and immersed in fresh water, 10% sodium sulfate solution for 28, 91, 182, and 365 days, respectively. To evaluate the long-term durability to chloride ion and sulfate attack for the cementless concrete specimens, the diffusion coefficient for chloride ion and compressive strength ratio, mass change ratio, and length change ratio were measured according to the NT BUILD 492 and JSTM C 7401, respectively. It was observed from the test results that the resistance against chloride ion and sulfate attack of the cemetntless concrete were comparatively largely increased than those of OPC concrete irrespective of water-binder ratio.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.349-355
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• 2015

Background: The tuberculin skin test (TST) is the standard tool to diagnose latent tuberculosis infection (LTBI) in mass screening. The aim of this study is to find an optimal cut-off point of the TST+ rate within tuberculosis (TB) contacts to predict the active TB development among adolescents in school TB outbreaks. Methods: The Korean National Health Insurance Review and Assessment database was used to identify active TB development in relation to the initial TST (cut-off, 10 mm). The 7,475 contacts in 89 schools were divided into two groups: Incident TB group (43 schools) and no incident TB group (46 schools). LTBI treatment was initiated in 607 of the 1,761 TST+ contacts. The association with active TB progression was examined at different cut-off points of the TST+ rate. Results: The mean duration of follow-up was $3.9{\pm}0.9years$. Thirty-three contacts developed active TB during the 4,504 person-years among the TST+ contacts without LTBI treatment (n=1,154). The average TST+ rate for the incident TB group (n=43) and no incident TB group (n=46) were 31.0% and 15.5%, respectively. The TST+ rate per group was related with TB progression (odds ratio [OR], 1.025; 95% confidence interval [CI], 1.001-1.050; p=0.037). Based on the TST+ rate per group, active TB was best predicted at TST+ ${\geq}$ 16% (OR, 3.11; 95% CI, 1.29-7.51; area under curve, 0.64). Conclusion: Sixteen percent of the TST+ rate per group within the same grade students can be suggested as an optimal cut-off to predict active TB development in middle and high schools TB outbreaks.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.366-375
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• 2018

Evapotranspiration (ET) information is needed for many applications in agricultural and environmental resource management because crop yields, plant growth and physiological characteristics are primarily water limited. This study was conducted to evaluate the diurnal change of ET using electronic weighing lysimeter and to determine whether the ET of Cnidium officinale Makino could be manipulated through meteorological factors such as solar radiation, windy conditions and air temperature etc., Pot has a diameter of 35 cm and an height of 38 cm. A disturbed soil of sandy loam (coarse, mixed, mesic family of Dystric Fluventic Eutroudepts) within lysimeter has a mass of approximately 40.0 kg. In 2017, 10-minute recordings of data were used for measuring actual ET, and also evaluating a relationship between ET and meteorological factors during from 2 Aug. to 6 Aug. The maximum daily ET of Cnidium officinale was $44.04{\pm}3.949g$ per hour in lysimetric measurements. Diurnal changes of ET was highly correlated with solar radiation ($r^2=0.7778$) and followed by wind speed ($r^2=0.6400$). But on the other hand, air temperature was not consistent with ET ($r^2=0.2260$). This results imply that ET of Cnidium officinaele seems to be mainly governed by radiation energy in clear days, and approximately 40% of solar radiation is likely to be converted into ET. Therefore, weighing lysimeter can be used to accurately estimate actual ET and is expected to attract a great deal of attention to reliable application of water management in agriculture.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.209-216
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• 2019

Objective: We compare the effects of three different approved sources of supplemental zilpaterol on growth-performance responses and carcass characteristics of finishing lambs. Methods: Twenty four Pelibuey${\times}$Katahdin lambs ($46.75{\pm}2.43kg$) were used in a 33-day feeding trial. Lambs were fed a dry rolled corn-based finishing diet. Treatments consisted of the non-supplemental basal diet (Control) versus the basal diet supplemented with 125 mg zilpaterol/kg of diet (as fed basis) from three commercial sources marketed in Mexico: Zilmax (ZIL), Grofactor, and Zipamix. Results: Compared to controls, zilpaterol (ZH) supplementation did not affect dry matter intake (DMI), but increased carcass adjusted daily weight gain (ADG, 36.7%), gain efficiency (34.2%), and dietary net energy (26.0%), and decreased (23.4%) the ratio of observed:expected DMI. Compared to controls, supplemental ZH increased hot carcass weight (6.4%), dressing percentage (3.2%), m. longissimus thoracis (LM) area (15.6%), and shoulder muscle:fat ratio (28.7%), but decreased kidney-pelvic-heart fat, and fat thickness. Supplemental ZH increased 10.9% and 14.3% whole cut weight of loin and leg, respectively, and the proportion (as percentage of cold carcass weight) of leg (4.3%). These increases were reflected in greater forequarter and hindquarter weights. Lambs fed ZH increased (4.6%) empty body weight (EBW) and reduced (14.7%) liver/spleen weight (as g/kg EBW). Likewise, ZH supplementation tended (p = 0.08) to lower (8.9%) visceral fat. Growth performance, energetic efficiency, hot carcass weight, dressing percentage, LM area and whole cuts were not different across supplemental ZH sources. However, compared with non-supplemented controls, only ZIL appreciably decreased carcass fat distribution, including fat thickness, percentage kidney pelvic and heart fat, shoulder fat, and visceral fat. Conclusion: Supplemental ZH increases ADG, gain efficiency, carcass dressing percentage, and LM area. The magnitude of these responses was similar among ZH sources. Nevertheless, compared with non-supplemented controls, only ZIL appreciably decreases carcass fat. The basis for this is uncertain, but indicative that some practical differences in zilpaterol bio-equivalency may exist across commercial sources tested.