• Health Policy and Management
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• v.25 no.4
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• pp.277-284
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• 2015

Background: This study investigates the relationship of socioeconomic status with adverse birth outcomes (low birth weight, preterm birth) and the relationship of socioeconomic status with infant mortality, using the birth cohort in Korea, 1995-2010. Methods: 8,648,035 births from National Statistics Offics, 1995-2010 were studied with respect to social variation in adverse birth outcomes and infant mortality in Korea. The effect of social inequality was examined against adverse birth outcomes and infant mortality using multivariate logistic regression after controlling for other covariates. Results: Social inequality were observed in adverse birth outcomes: low birth weight (LBW, 1,500-2,499 g), very LBW (1,000-1,499 g), and extremely LBW (500-999 g) as well as moderately preterm birth (PTB, 33-36 weeks), very PTB (28-32 weeks), extremely PTB (22-27 weeks), and infant mortality. The effect of social inequality was higher among moderately LBW (1,500-2,499 g) and PTB (33-36 weeks) than very or extremely LBW and PTB. Conclusion: The social inequality in adverse birth outcomes (low birth weight and preterm) and infant mortality existed and increased in Korea from 1995 to 2010. The effect of maternal education on adverse birth outcomes as well as infant mortality was apparent in the study results. Especially, social inequailiy in infant mortality was greater among the sub-normal births (low birth weight [1,500-2,499 g] or preterm birth [33-36 weeks]), which suggests, social interventions should aim at more among the subnormal births. This study suggest that tackling inequality in births as well as infant mortality should be focused on the social inequality itself.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.155-159
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• 2016

Background: Nuclear reactors produce a great number of antielectron neutrinos mainly from beta-decay chains of fission products. Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may take part in special weak interactions. We calculate reactor antineutrino spectra especially in the low energy region. In this work we present neutrino spectrum from a typical pressurized water reactor (PWR) reactor core. Materials and Methods: To calculate neutrino spectra, we need information about all generated nuclides that emit neutrinos. They are mainly fission fragments, reaction products and trans-uranium nuclides that undergo negative beta decay. Information in relation to trans-uranium nuclide compositions and its evolution in time (burn-up process) were provided by a reactor code MVP-BURN. We used typical PWR parameter input for MVP-BURN code and assumed the reactor to be operated continuously for 1 year (12 months) in a steady thermal power (3.4 GWth). The PWR has three fuel compositions of 2.0, 3.5 and 4.1 wt% $^{235}U$ contents. For preliminary calculation we adopted a standard burn-up chain model provided by MVP-BURN. The chain model treated 21 heavy nuclides and 50 fission products. The MVB-BURN code utilized JENDL 3.3 as nuclear data library. Results and Discussion: We confirm that the antielectron neutrino flux in the low energy region increases with burn-up of nuclear fuel. The antielectron-neutrino spectrum in low energy region is influenced by beta emitter nuclides with low Q value in beta decay (e.g. $^{241}Pu$) which is influenced by burp-up level: Low energy antielectron-neutrino spectra or emission rates increase when beta emitters with low Q value in beta decay accumulate Conclusion: Our result shows the flux of low energy reactor neutrinos increases with burn-up of nuclear fuel.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8877-8881
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• 2014

Background: Despite social gradients in adult smoking, the effects of socioeconomic position (SEP) on adolescent smoking is not well understood. This study examined effects of subjective SEP as well as the objective SEP on smoking among Korean adolescents. Materials and Methods: Data were obtained from the 2012 Korea Youth Risk Behavior Web-based Survey, a nationally representative sample of middle and high school students (38,221 boys; 35,965 girls). SEP was assessed by the Family Affluence Scale (FAS) and the self-rated household economic status. Relationships between SEP and smoking were analyzed by multivariate logistic regression. Results: The low perceived SEP for either the high or low FAS grade was related to an elevated likelihood of smoking in both genders. A significantly higher risk of smoking was found in boys of low perceived SEP in middle school (odds ratio [OR] 1.50; 95% confidence interval [CI] 1.28-1.77 for high FAS, OR 1.55; 95% CI 1.21-1.98 for low FAS), and of low perceived SEP and high FAS in high school (OR 1.13; 95% CI 1.02-1.26). Among girls, an elevated risk of smoking was observed in middle school group with low perceived SEP and low FAS (OR 2.01; 95% CI 1.44-2.79) and in the high school group of low perceived SEP, regardless of FAS level (OR 1.34; 95% CI 1.14-1.57 for high FAS, OR 1.31; 95% CI 1.04-1.65 for low FAS). Conclusions: The relationship of subjectively perceived SEP with smoking is as important as objective SEP and more significant in Korean high school adolescents.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.49-54
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• 2013

Background: The purposed of this study is to examine the static and dynamic plantar foot pressure in chronic low back pain patients and normal adults. Methods: The subjects were divided into a group of 30 patients with chronic low back pain and a control group of 30 healthy persons. While static posture and dynamic posture at comfortable walking speeds, the low back pain group and the control group measured their plantar foot pressure and the trajectory of their center of pressure (COP) using the Matscan(R) system. Independent t-tests were measured to compare differences in plantar foot pressure characteristics between the left side and right side of the low back pain group and the control group. Results: In the comparison of differences in plantar foot pressure characteristics between the left side and right side of the low back pain group and the control group, the anteroposterior (AP) displacement of COP showed significant differences (p<.05). Although the low back pain group and the control group did not show any significant differences in leg length, weight distribution, mediolateral (ML) displacement of COP, static contract area, dynamic contract areas (p>.05), increases in the contract area values were shown in the hind foot in general. Conclusion: In this study, it was shown that patients with chronic low back pain were walking with short AP displacement of the COP as a compensatory action to avoid pain.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.36-41
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• 2006

In this paper, the time evolution of undoped GaN epilayers on a low-temperature GaN buffer layer grown on c-plane sapphire at a low pressure of 300 Torr was studied via a two-step growth condition in a horizontal MOCVD reactor. As a function of the growth time at a high-temperature, the surface morphology, structural quality, and optical and electrical properties were investigated using atomic force microscopy, high-resolution x-ray diffraction, photoluminescence, and Hall effect measurement, respectively. The root-mean-square roughness showed a drastic decrease after a certain period of surface roughening probably due to the initial island growth. The surface morphology also showed the island coalescence and the subsequent suppression of three-dimensional island nucleation. The structural quality of the GaN epilayer was improved with increasing growth time considering the symmetrical (002) and asymmetrical (102) rocking curves. The variations of room-temperature photoluminescence, background carrier concentration, and Hall mobility were measured and discussed.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.1
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• pp.16-22
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• 2010

Cast austenitic stainless steel(CASS) is used in the primary cooling piping system of nuclear power plant for it's relative low cost, corrosion resistance and easy of welding. However, the coarse-grain structure of cast austenitic stainless steel can strongly affect the inspectability of ultrasonic testing. The major problems encountered during inspection are beam skewing, high attenuation and high background noise of CASS component. So far, the best inspection performance involving CASS components have been achieved using low frequency TRL(Transmitter/Receiver side-by-side L wave) angle beam probe. But TRL technique could not detect shallow defect and it contains an uncertainty for sizing capability. Currently, most of researchers are studying to overcome these challenge issue. In this study, low-frequency phased array TRL technique used to detect and sizing the flaws in CF8A cast austenitic stainless steel.As conclusion, we could detect and size not only axial flaw but also circumferential flaw using low frequency phased array technique.

• The Journal of Internal Korean Medicine
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• v.31 no.3
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• pp.612-619
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• 2010

Background : Low level laser therapy may be an effective method to protect tissue damage in acute stroke. Recently, series of clinical studies on the basis of animal experiments report efficacy and safety of laser therapy at early stages of acute stroke. Laser promotes mitochondrial ATP synthesis to reduce cell death by ischemic infarction. Objectives : To report possibility of non-invasive laser therapy for acute stroke by reviewing literature about its effectiveness, safety and mechanism. Methods : We searched papers using PubMed and 'Web of Knowledge' of Thomson ISI, using the keywords "Laser Therapy, Low-Level" and "Stroke". Limitations were last 10 years of publications and only in English. Search range includes RCTs, clinical reports, reviews and animal experiments. Papers not matched with inclusion criteria were excluded. Results : A total 223 studies were found, 203 excluded during title and extract screening. After scanning 20 papers the final 2 serial RCTs were selected and analyzed. They reported that transcranial laser therapy led in neuroprotective effect for acute stroke patents. Clinical evaluation factors showed favorable trend and initial safety. Conclusions : Non-invasive laser secured safety of clinical application. It may be a favorable choice for the acute stage of stroke.

• Health Policy and Management
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• v.28 no.2
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• pp.162-167
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• 2018

Background: In this research, we conducted an analysis to grasp the relationship between hearing and quality of life and to prepare effective troubleshooting. Methods: In this study, we analyzed using the data of the 6th term of the National Health and Nutrition Survey of the Disease Management Headquarters. And, out of 7,380 people, 3,598 adults over the age of 40 years who participated in the hearing test were selected as final research subjects and analyzed. Results: It was confirmed that the result of the analysis affects the quality of life based on hearing. The quality of life associated with hearing loss was unpleasant, motor ability, anxiety/depression, and everyday life affected in order of self management. And factors having an effect on the quality of life of the study subjects were found to be gender, elderly, unmarried, low hearing, low household income, absence of economic activity, and low teaching standards. Conclusion: The conclusion is that strengthening education for realistic management and prevention rather than treatment for unconditional hearing impairment will overcome low self esteem and loneliness and alleviate any uncomfortable life that people with hearing loss give. It is expected to be possible.

• The Korean Journal of Pain
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• v.31 no.3
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• pp.199-205
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• 2018

Background: Sleep disturbance and depression are becoming more recognized as important symptoms among individuals with chronic low back pain. This study evaluated the effect of stabilization exercise on pain-related disability, sleep disturbance and the psychological status of patients with non-specific chronic low back pain (NSCLBP). Methods: A total of 26 patients (M/F = 17/9) with NSCLBP with a mean age of $50.0{\pm}15.5$ took part in this study. Participants were recruited from selected hospitals in Lagos state. Ethical approval was sought and obtained from the health research and ethics committee of Lagos University Teaching Hospital Idi-araba, Lagos, Nigeria. Participants performed stabilization exercise for eight weeks consecutively and were assessed for pain-related disability, anxiety, depression, and sleep disturbance using the pain-disability index, hospital anxiety and depression scale, and the insomnia severity index at baseline, the 4th week, and the 8th week, postintervention. Results: The participants studied recorded significant reduction in pain-related disability (P = 0.001). There was also improvement in the sleep quality (P = 0.001), depression level (P = 0.001), and anxiety level (P = 0.001), post intervention. Conclusions: This study revealed that stabilization exercise is very useful in the management of sleep disturbance, pain-related disability, depression, and anxiety in NSCLBP patients.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.736-740
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• 2007

A laboratory study on low frequency noise assessment has been carried out to evaluate the relevance of the weighting curve. Especially, the A-weighting curve which is used in most noise assessments has been evaluated using the acceptability limit in this study. The acceptability limit is one of the indicators in which the subjective responses were well-reflected. For the measurement of the acceptability limit, pure tone stimuli were used in the frequency range between 20 and 200 Hz. The measurement was proceeded in the anechoic chamber to minimize the background noise level. A total of 29 test subjects, who were aged between 19 to 33 years, participated in this study. They had been exposed to various stimuli for about 1 hour by supra-aural earphone. The measurement consisted of two listening sessions: hearing threshold and the acceptability limit session. The results showed that the tendency of the acceptability limit curve was approximately equal to C-weighting curve which had been found to be superior to A-weighting curve in assessment of low frequencies.