• Neonatal Medicine
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• v.18 no.2
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• pp.328-336
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• 2011

Purpose: An association between very low birth weight infants(VLBWI) and hearing loss has long been recognized. Early identification and intervention for hearing loss benefits language and speech/cognitive development. We investigated the risk factors and clinical outcomes of hearing loss among VLBWI. Methods: We analyzed the results of auditory brainstem response (ABR) testing of VLBWI. These infants were admitted to the neonatal intensive care unit (NICU) of Pusan National University Yangsan Hospital between December 2008 and February 2011. A follow-up was conducted subsequently. Results: ABR evaluations were performed on 65 infants, and 31 showed abnormal results (47.7%). Among the 31 infants, 10 were classified with moderate/severe/profound hearing loss (15.4%). The infants with abnormal ABR had a higher incidence of low birth weight, prolonged ventilator care, cumulative dose of furosemide, and the lowest $PaO_2$ (P<0.05). Those with moderate/severe/profound hearing loss had a higher incidence of low Apgar scores at 5 minutes (odds ratio[OR],0.34; 95% confidence interval[CI],0.13-0.89), prolonged ventilator care (OR,1.06; 95% CI,1.01-1.12), and mild hearing loss compared to those without profound hearing loss. Follow-up evaluations on eight infants with ABR reveled improvements 5.6${\pm}$3.9 months later. One infant, who had profound hearing loss in both ears, used a hearing aid. Conclusion: Factors influencing hearing loss at the first VLBWI hearing screening test included lower Apgar scores at 5 min and prolonged use of a ventilator. Most VLBWI with hearing losses were expected to recover after several months of follow-up.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.33-39
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• 2006

Purpose: To determine appropriate sampling frequency and time of multiple blood sampling dual exponential method with $^{99m}Tc$-DTPA for calculating glomerular filtration rate (GFR). Materials & Methods: Thirty four patients were included in this study. Three mCi of $^{99m}Tc$-DTPA was intravenously injected and blood sampling at 9 different times, 5ml each, were done. Using the radioactivity of serum, measured by gamma counter, the GFR was calculated using dual exponential method and corrected with the body surface area. Using spontaneously chosen 2 data points of serum radioactivity, 15 collections of 2-sample GFR were calculated. And 10 collections of 3-sample GFR and 12 collections of 4-sample GFR were also calculated. Using the 9-sample GFR as a reference value, degree of agreement was analyzed with Kendall's $\tau$ correlation coefficients, mean difference and standard deviation. Results: Although some of the 2-sample GFR showed high correlation coefficient, over or underestimation had evolved as the renal function change. The 10-120-240 min 3-sample GFR showed a high correlation coefficient (${\tau}=0.93$), minimal difference ($Mean{\pm}SD=-1.784{\pm}3.972$), and no over or underestimation as the renal function changed. The 4-sample GFR showed no better accuracy than the 3-sample GFR. Conclusions: In the wide spectrum of renal function, the 10-120-240 min 3-sample GFC could be the best choice for estimating the patients' renal function.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.52-60
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• 2001

Purpose: In young male patients who suffered several kinds of trauma with subsequent suspicious reflex sympathetic dystrophy syndrome, we performed three-phasic bone scan in order to investigate its usefulness. Materials and Methods: Patients with narrow range of age (21-25. mean $22.8{\pm}1.3$, all male) were included with suspicious reflex sympathetic dystrophy syndrome of 12 feet and 5 hands. Only one was bilateral feet case and 16 were ipsilateral (Rt:13, Lt:3). The etiologic traumas were 4 fractures, 4 sprains, 3 blunt trauma, 2 cellulitis, 1 tendon tear, 1 crush injury, 1 overexercise, and 1 unknown. Radiologically 3 showed osteoporotic changes. Three-phasic bone scans were performed $21.2{\pm}7.3wks$ after trauma. Results: According to symptom complex, confirmatory reflex sympathetic dystrophy syndrome 4 cases and suspicious 13 were analyzed. All confirmatory cases (100%) showed increased uptake at delay phase with periarticular accentuation. Of confirmatory 4 cases, 2 showed increased uptake in all three phases (perfusion: P, blood pool: B, and delay: D), and other 2 revealed decreased P but, both increased B and D. Of suspicious 13 cases, 9(69.2%) had increased D (4 periarticular and 5 focal), 2 decreased D, and 2 symmetric D. In 12 foot cases, so-called weight hearing patterns - increased contralateral sole at P and B - were revealed in 7(58.3%). Conclusion: Diffuse periarticular increased uptake at delay phase of three-phasic bone scan was a compatible finding to reflex sympathetic dystrophy syndrome in young male patients whose symptom complex strongly designated post traumatic reflex sympathetic dystrophy syndrome.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.194-200
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• 2007

Purpose: $^{13}N$-ammonia is a well known radiopharmaceutical for the measurement of a myocardial blood flow (MBF) non-invasively using PET-CT. In this study, we investigated a correlation between MBF obtained from dynamic imaging and myocardial perfusion score (MPS) obtained from static imaging for usefulness of cardiac PET study. Methods: Twelve patients (11 males, 1 female, $57.9{\pm}8.6$ years old) with suspicious coronary artery disease underwent PET-CT scan. Dynamic scans (6 min: $5\;sec\;{\times}\;12,\;10\;sec\;{\times}\;6,\;20\;sec\;{\times}\;3,\;and\;30\;sec\;{\times}\;6$) were initiated simultaneously with bolus injection of 11 MBq/kg $^{13}N-ammonia$ to acquire rest and stress image. Gating image was acquired during 13 minutes continuously. Nine-segment model (4 basal walls, 4 mid walls, and apex) was used for a measurement of MBF. Time activity curve of input function and myocardium was extracted from ROI methods in 9 regions for quantification. The MPS were evaluated using quantitative analysis software. To compare between 20-segment model and 9-segment model, 6 basal segments were excluded and averaged segmental scores were used. Results: There are weak correlation between MBF (rest, 0.18-2.38 ml/min/g; stress, 0.40-4.95 ml/min/g) and MPS (rest 22-91%, stress, 14-90%), however the correlation coefficient between corrected MBF and MPS in rest state was higher than stress state (rest r=0.59; stress r=0.80). As a thickening increased, correlation between MBF and MPS also showed good correlation at each segments. Conclusions: Corrected and translated MPS as its characteristics using $^{13}N$-ammonia showed good correlation with absolute MBF measured by dynamic image in this study. Therefore, we showed MPS is one of good indices which reflect MBF. We anticipate PET-CT could be used as useful tool for evaluation of myocardial function in nuclear cardiac study.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.105-108
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• 1993

A new devised conductivity meter was used in the rapid and convenient determination of salt contents of soysauce and margarine. The equation $(1){\sim}(5)$ was set up between the electric conductivity (x) for 100 times diluted solution of soysauce and the salt contents (y). y=0.083x-1.253 $(at\;15^{\circ}C)$ (1) y=0.077x-2.062 $(at\;20^{\circ}C)$ (2) y=0.071x-2.686 $(at\;25^{\circ}C)$ (3) y=0.066x-3.153 $(at\;30^{\circ}C)$ (4) y=0.062x-3.522 $(at\;35^{\circ}C)$ (5) y=(-0.001139t+0.0999)x+(-0.126t+0.557) $(temperature\;range;\;15{\sim}35^{\circ}C)$ (6) y=salt contents [%], x=conductivity $[{\mu}{\Omega}^{-1}{\cdot}cm^{-1}]$, $t=temp.\;[^{\circ}C]$. The salt contents could be estimated by the equation $(1){\sim}(6)$ and the measured conductivity. The estimated salt contents agreed with that determined by conventional method within 0.27[%] as salt contents. For margarine, the equation (7) was setup between the conductivity (x) and the salt contents (y) y=0.00266x+0.057 $(at\;20^{\circ}C)$ (7) y=salt contents [%], x=conductivity $[{\mu}{\Omega}^{-1}{\cdot}cm^{-1}]$ The salt contents estimated with the equation (7) and the measured condutivity agreed with that determined by conventional method within 0.028[%] as salt contents. The electric conductivity obtained with conductivity meter could be a valuable criteria salt contents test of Korean soysauce and margarine determining in a few second or minute by handy compact portable meter.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.1-7
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• 2003

Time domain reflectometry (TDR) is a newly developed method for measuring simultaneously solute concentrations and volumetric water content of soil. Bulk electrical conductivity ($EC_a$) of soil is obtained from TDR signal using several equations proposed, and electrical conductivity of soil solution ($EC_w$) can be calculated using the linear relationship $EC_a=EC_w\theta(a\theta+b)+EC_s$ between $EC_a$ and $EC_w$ at constant soil water content. The objectives of this study were to evaluate $EC_a$ proposed by several workers and to obtain the empirical constants (a, b, and $EC_s$) for $EC_w$ of the soils from A, Bl, and B2 horizon of an agricultural field (Coarse loamy, Fluvaquentic Eutrudepts). The $EC_a$ proposed by Yanuka et al. responded most sensitively to the KCl solute concentrations. The empirical constants of a, b, and $EC_s$ for $EC_w$ were -0.249, 1.358, and 0.054 for A horizon, -2.518, 2.708, and 0.097 for Bl horizon, and 2.490, -0.250, and 0.103 for B2 horizon, respectively. Therefore, the results of this study showed that Yanuka et al. equation was most useful one in determining $EC_a$, from TDR signal for agricultural soil with low salinity and that the empirical constants for the calculation of $EC_w$, from $EC_a$ can be obtained through a simple calibration experiment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.461-475
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• 2006

In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the $2{\times}2$ active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by $90^{\circ}$ rotating arrangement of four radiating elements polarized circularly by a $90^{\circ}$ hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at $P_{1dBc}$ of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.

• Korea journal of population studies
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• v.29 no.2
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• pp.53-88
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• 2006

The major aim of this paper is to develop a hypothetical set of age-specific fertility rates which are logically derived and reasonably accurate in the projection of future population. The first procedure is to select a generalized log-gamma distribution model, which includes Coale-McNeil nuptiality model, in order to estimate and project a set of age-specific fertility rates by birth cohort and birth order. The second is to apply the log-gamma model with an empirical adjustment to the actual data to estimate and project the future fertility rates for relatively young birth cohorts who did not complete their reproductive career. This study reconstructs or translates a set of cohort age-specific fertility rates into a set of period age-specific fertility rates which must be hypothesized in order to establish the broader framework of future population projection. For example, the fertility at age 20 in the year of 2020 is the fertility at age 20 for the cohort born in 1990, while the fertility at age 21 in the year of 2020 is the fertility at 21 for the cohort born in 1989. In turn, once a set of age-specific fertility rates for the cohorts who were born up to the year of 2010, it is possible for one to establish an hypothetical set of period age-specific fertility rates which will be needed to project the future population until the year of 2055. The difference in the hypothetical system of age-specific fertility rates between this study and the 2005 special population projection comes from the fact that the fertility estimation/projection model used in this study was skillfully exploited to reflect better actual trend of fertility decline caused by rise in marriage age and increasing proportion of those who remain single until their end of reproduction. In this regard, this paper argues that the set of age-specific fertility rates derived from this study is more logical and reasonably accurate than the set of those used for the 2005 special projection. In the population projection, however, the fundamental issue of the hypothetical setting of age-specific fertility rates in relation to the fertility estimation/projection model is about how skillfully one can handle the period effects. It is not easy for one to completely cope with the problem of period effects except for the a minor period adjustment based on recent actual data, along with the given framework of a cohort-based fertility estimation/projection model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2293-2303
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• 2013

Objective: This study aims to determine whether national patient safety indicators (PSIs) can be calculated. Methods: Using PSI criteria from Organization for Economic Co-Operation and Development (OECD) Health Technical Papers 19 based on the Agency for Healthcare Research and Quality (AHRQ), PSIs were identified in the Korean National Hospital Discharge In-depth Injury Survey (KNHDIIS) database for 875,622 inpatient admissions between 2004 and 2008. Logistic regression was used to estimate factors of variations for PSIs. Results: From 2004 to 2008, 3,084 PSI events of 8 PSIs occurred for over 80 thousands discharges. Rates per 1,000 events for decubitus ulcer (PSI3, 4.88), foreign body left during procedure (PSI5, 0.05), postoperative sepsis (PSI13, 1.32), birth trauma-injury to neonate (PSI17, 7.92) and obstetric trauma-vaginal delivery (PSI18, 32.81) are all identified between ranges from maximum to minimum of OECD rates, respectively. However, rates per 1,000 events for selected infections due to medical care (PSI7, 0.22), postoperative pulmonary embolism or deep vein thrombosis (PSI12, 0.90) and accidental puncture or laceration (PSI15, 0.71) are below the minimum of OECD range. 7 PSIs except PSI 18 showed statistically significant relationship with number of secondary diagnoses. When adjusting patient characteristics, there are statistically significant different rates according to bed size or location of hospitals. Conclusion: This is the first empirical study to identify nationally number of adverse events and PSIs using administrative database. While many factors influencing these results such as quality of data, clinical data and so on are remain, the results indicate opportunities for estimate national statistics for patient safety. Furthermore outcome research such as mortality related to adverse events is needed based on results of this study.

• Clinical and Experimental Pediatrics
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• v.51 no.10
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• pp.1065-1070
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• 2008

Purpose : This study aims to determine whether early closure (within 7 d) of significant patent ductus arteriosus (PDA) with indomethacin or ligation reduces neonatal morbidity when compared with delayed closure (after 7 d). Methods : Fifty-eight extremely-low-birth-weight infants admitted to the NICU of Seoul National University Hospital from April 2005 to May 2007 with PDA were studied retrospectively. Results : The mean gestational age (GA) was $26{\pm}2weeks$ (range, 23-32 wk), and the birth weight was $782{\pm}146g$ (range, 430-990 g). The delayed closure group was associated with early GA ($25.7{\pm}1.7wk$ vs $27.1{\pm}2.0wk$, P=0.013), in vitro fertilization (IVF) (55% vs 24%, P=0.017), and the absence of preeclampsia (5% vs. 34%, P=0.013). There was no difference in ductal size between the early closure and delayed closure groups. The incidence of bronchopulmonary dysplasia (95% vs 65%, P=0.012) and intraventricular hemorrhage (70% vs. 39%, P=0.027) increased in the delayed closure group. Using regression analysis adjusted for gestational age, delayed closure correlated positively with the duration of ventilator support (P=0.008), hospitalization (P=0.020), time to full enteral feeding (P<0.001), and total parenteral nutrition (P=0.010). Conclusion : Delayed closure of the hemodynamically significant patent ductus arteriosus in extremely-low-birth-weight infants is significantly related to the development of various morbidities. Thus, early closure of PDA is needed within the first week of life.