• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.503-511
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• 2018

Background: Sampling a healthy reference population to generate reference intervals (RIs) for complete blood count (CBC) parameters is not common for pediatric and geriatric ages. We established age- and sex-specific RIs for CBC parameters across pediatric, adult, and geriatric ages using secondary data, evaluating patterns of changes in CBC parameters. Methods: The reference population comprised 804,623 health examinees (66,611 aged 3-17 years; 564,280 aged 18-59 years; 173,732 aged 60-99 years), and, we excluded 22,766 examinees after outlier testing. The CBC parameters (red blood cell [RBC], white blood cell [WBC], and platelet parameters) from 781,857 examinees were studied. We determined statistically significant partitions of age and sex, and calculated RIs according to the CLSI C28-A3 guidelines. Results: RBC parameters increased with age until adulthood and decreased with age in males, but increased before puberty and then decreased with age in females. WBC and platelet counts were the highest in early childhood and decreased with age. Sex differences in each age group were noted: WBC count was higher in males than in females during adulthood, but platelet count was higher in females than in males from puberty onwards (P <0.001). Neutrophil count was the lowest in early childhood and increased with age. Lymphocyte count decreased with age after peaking in early childhood. Eosinophil count was the highest in childhood and higher in males than in females. Monocyte count was higher in males than in females (P <0.001). Conclusions: We provide comprehensive age- and sex-specific RIs for CBC parameters, which show dynamic changes with both age and sex.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.481-488
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• 2009

It has been reported that the magnitude and the development rate of autogenous shrinkage of cement paste, mortar and concrete were affected by history and magnitude of inner temperature at an early age. But it was not enough to explain the relation between hydration heat and autogenous shrinkage at an early age, because there was no certain analysis on histories of hydration heat and autogenous shrinkage in previous studies. In our prior study, to understand the relationship between hydration heat and autogenous shrinkage of concrete at an early age, the analysis method for histories of hydration heat and autogenous shrinkage was suggested. Based on this method, early age properties of hydration heat and autogenous shrinkage of high strength concrete with different sizes and hydration retardation were investigated in this study. As a result of the study, properties of hydration temperature and autogenous shrinkage were different according to specimen size and hydration retardation. However, there was a close relationship between hydration temperature and autogenous shrinkage at an early age, especially between HHV and ASV as linear slopes of the sections where hydration temperature and autogenous shrinkage increase rapidly; the higher HHV, the higher ASV and the greater ultimate autogenous shrinkage. And it was found that, among the setting time, bend point and temperature increasing point, they were close relationship each other on cement hydration process.

• Journal of the Korean Home Economics Association
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• v.46 no.2
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• pp.1-12
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• 2008

The purpose of this research was to identify the importance of social competence in early childhood, age 3 to 5, by examining the relationship between the children's variables such as gender, age, and temperament, with that of their mothers' emotionality, and the social competence. 72 children in the early childhood age bracket were surveyed. Three major findings were established. Firstly, there were no gender differences in relation to social competence. Children's adaptability and social activity were related to their pro-social behavior and the ability to internalize/externalize problems. Secondly, children exhibited pro-social behavior only when their mother's emotional reactivity was positive. hirdly, children's social competence was influenced by individual variables and their mothers' emotionality. Prosocial behavior, a lower ranking domain, was influenced by children's adaptability and mothers' emotional reactivity. The children's ability to internalize problem was influenced by adaptability. In contrast, The ability to externalize problem was influenced by the range of activities they were involved in. Overall, children's social competence was influenced by their age.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.63-71
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• 2010

This paper is about a research of steam curing which is one of the curing methods for accelerating the early-age strength of pre-cast concrete. With cylinder mold and mock-up specimen, the research was executed to study the best cycle of steam curing temperature through quantifying cycle of steam curing and maximum temperature, while the required strength is developed under the early-age. Moreover, causes and measurements for the high temperature of concrete, which is due to the steam curing, and the crack, which occurs when removing steel form, are stated. Ultimately, the economical method of producing, which satisfies early-age strength development and quality assurance while manufacturing PC structure, is stated.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.6
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• pp.501-508
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• 2007

This paper presents the feasibility of using electromechanical impedance based active sensing technique for nondestructive strength gain monitoring of early-age concrete by employing piezoelectric lead-zirconate-titanate (PZT) patches on concrete surface. The strength development of early age concrete is actively monitored by performing a series of experiments on concrete specimens under moist curing condition. The electrical admittance signatures are acquired for five different curing ages and compared with each other. The resonant frequency shifts of PZT patches with increasing days is observed which is on account of additional stiffening due to strength gain of concrete during curing and level of stiffening being related to strength obtained from compression tests on companion cylinder specimens. The proposed approach is found to be suitable for monitoring the development of compressive strength in early-age concrete. It is also observed in this study that root mean square deviation (RMSD) in admittance signatures of the PZT patches can also be used as an indicator of concrete strength development.

• Journal of Preventive Medicine and Public Health
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• v.48 no.4
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• pp.216-224
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• 2015

Objectives: Decreased fertility and impaired health owing to early menopause are significant health issues. Smoking is a modifiable health-related behavior that influences menopausal age. We investigated the effects of smoking-associated characteristics on menopausal age in Korean women. Methods: This study used data from the Korea National Health and Nutrition Examination Survey from 2007 to 2012. Menopausal age in relation to smoking was analyzed as a Kaplan-Meier survival curve for 11 510 women (aged 30 to 65 years). The risk of entering menopause and experiencing early menopause (before age 48) related to smoking were assessed using a Cox proportional hazards model. Results: The menopausal age among smokers was 0.75 years lower than that among non-smokers (p<0.001). The results of the Cox proportional hazards model showed pre-correction and post-correction risk ratios for entering menopause related to smoking of 1.26 (95% confidence interval [CI], 1.09 to 1.46) and 1.27 (95% CI, 1.10 to 1.47), respectively, and pre-correction and post-correction risk ratios for experiencing early menopause related to smoking of 1.36 (95% CI, 1.03 to 1.80) and 1.40 (95% CI, 1.05 to 1.85), respectively. Conclusions: Smokers reached menopause earlier than non-smokers, and their risk for experiencing early menopause was higher.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.521-529
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• 2000

Objectives : To assess height, weight and body mass index from childhood to adolescence according to the age at menarche and hence to study the influence of childhood growth on the menarche age. Methods : $\lceil$The Kangwha Study$\rfloor$was a community-based prospective cohort study which included the entire population of 219 female first graders in Kangwha county in 1986. Among the 219 girls, 119 girls who had received complete follow up checks during the study period$(1986\sim1997)$, were included in this study, except one for whom menarche age information was unavailable. The remaining 118 girls were divided into three groups according to the timing of menarche : early(<25 percentile), intermediate and late($\geq75$ percentile) maturers. Results : The average age at menarche was 12.7 years . early 11.3 years, intermediate 12.6 years and late 13.7 years. The early maturers were taller and heavier between $6\sim8$ years. But, the mean weight and body mass index at the menarche age did not differ statistically among the three groups. The weight and body mass index of the early maturers were consistently higher than those of the late maturers over the entire period of the study. Conclusions : Critical body weight and body mass index must be attained for menstruation to be attained and the age at menarche is largely determined by the childhood growth. In addition, it seems that childhood growth and age at menarche are associated with adolescent weight and body mass index.

• Anxiety and mood
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• v.7 no.1
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• pp.34-39
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• 2011

Objectives : An early age at onset of obsessive compulsive symptoms in family studies has been strongly associated with a more familial form of obsessive compulsive disorder (OCD). Further, many reports have suggested that early- and late- onset OCD represent separate subtypes of the disorder. The aim of this study was to investigate the associations between the glutamate receptor, the ionotropic, n-methyl-d-aspartate (NMDA) subunit 2B gene (GRIN2B) polymorphisms, and onset of OCD in the Korean population. Methods : We recruited 109 OCD patients and classified them into early- (age of onset <18 years) and late-onset groups (age of onset${\geq}$18). Genomic DNA was extracted from their blood after which the genotypes and allelic frequencies of the two GRIN2B polymorphisms (5072T/G and 5988T/C) were compared in the two groups. We also compared genetic data between child- (age of onset${\leq}$15) and adult-onset groups (age of onset${\geq}$19) using the same protocol. Results : There were no significant differences between the early- and late-onset groups with respect to genotype. Moreover, we could not find any differences in genotype frequencies between child and adult-onset groups. Conclusions : Our study suggested that GRIN2B polymorphisms (5072T/G and 5988T/C) do not affect the onset of OCD in Koreans. However, this finding has resulted from a preliminary study and thus, further study is required.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.382-391
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• 2002

This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.813-822
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• 2002

The purpose of the present study is first to refine the mathematical material models for moisture and temperature distributions in early-age concrete and then to incorporate those models into finite element procedure. The three dimensional finite element program developed in the present study can determine the degree of hydration, temperature and moisture distribution in hardening concrete. It is assumed that temperature and humidity fields are fully uncoupled and only the degree of hydration is coupled with two state variables. Mathematical formulation of degree of hydration Is based on the combination of three rate functions of reaction. The effect of moisture condition as well as temperature on the rate of reaction is considered in the degree of hydration model. In moisture transfer, diffusion coefficient is strongly dependent on the moisture content in pore system. Many existing models describe this phenomenon according to the composition of mixture, especially water to cement ratio, but do not consider the age dependency. Microstructure is changing with the hydration and thus transport coefficients at early ages are significantly higher because the pore structure in the cement matrix is more open. The moisture capacity and sink are derived from age-dependent desorption isotherm. Prediction of a moisture sink due to the hydration process, i.e. self-desiccation, is related to autogenous shrinkage, which may cause early-age cracking in high strength and high performance concrete. The realistic models and finite element program developed in this study provide fairly good results on the temperature and moisture distribution for early-age concrete and correlate very well with actual test data.