• Title/Summary/Keyword: early ages

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Characteristics of Early Strength and Velocity Development in High Strength Concrete Containing Fly Ash (플라이애시를 함유한 고강도 콘크리트의 조기 강도와 속도 발현 특성)

  • 이회근;윤태섭;이광명
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.43-48
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    • 2001
  • The use of fly ash in cement and concrete industries has many benefits including engineering, economic, and ecological aspects. However, it has a disadvantage of low strength development, especially at early ages. In this study, in order to overcome this problem, the early strength accelerating agent($NA_{2}$ $SO_{4}$) was selected and applied to the production of high strength concrete(HSC) containing fly ash. It was found that the compressive strength of fly ash concrete incorporating TEX>$NA_{2}$ $SO_{4}$ has greater than that of concrete containing fly ash only until 7 days after casting. From the microstructural point of view, ettringite increased and pores decreased in fly ash concrete incorporating TEX>$NA_{2}$ $SO_{4}$ , leading to the development of early age strength. It was also found that the velocity vs. strength relationship of HSC is considerably different from that of low-strength concrete(LSC). Therefore, in order to predict early age strength of HSC, a estimation equation different from that for LSC is needed.

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The Relationship Between Serum Prostate Specific Antigen and Prostate Volume of Measured by Transrectal Ultrasonography (혈청 전립선특이항원과 경직장초음파로 측정된 전립선 용적과의 상관관계)

  • Kim, Mi-Young
    • Journal of radiological science and technology
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    • v.33 no.3
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    • pp.239-243
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    • 2010
  • Even though clinical use DRE, PSA and TRUS for screening while diagnosing prostate cancer early, however, we cannot achieve to diagnose it accurately by one method. Thus, mutual supplements are strongly required in diagnosis. It means that we should identify relationship between prostate volume and serum PSA under different ages for better diagnosis. The subjects(405 men) visited the department of diagnostic radiology in a general university hospital from January 2008 to December 2008, who was going to take the prostatic evaluation by TRUS. 13 men, who did definite diagnosis of prostate cancer before through biopsy, were excluded in this study. All data were expressed as mean and standard deviations by using SPSS 14.0 package programs and were analyzed by using one-way ANOVA to evaluate the effect of different ages. And Scheffe Post hoc comparison is accomplished in order to make significant difference in prostate volume, PSA and PSAD according to ages. Pearson correlation was used for ages, prostate volume, PSA and PSAD. According to examination, the subjects' prostate volume and serum PSA level increase as person's age. We can see significant difference between group over 70 years and group from 40 and 50 years. Moreover, age, prostate volume and serum PSA have significant positive correlation. Even though we can get variations in serum PSA level by changing prostate volume according to ages, it is worthwhile to mention that more strong association for prostate volume is observed than ages in elevation of serum PSA. Therefore, it is strongly recommended to consider prostate volume weightly when it comes to evaluate for men with elevated PSA level. Finally, TRUS is an excellent extra equipment to diagnose prostate cancer because it can contribute to early diagnose and pertinent treatment of prostate cancer.

Inhibition of advanced glycation end product formation by burdock root extract (우엉 뿌리 추출물의 최종당화산물 형성 억제 효능)

  • Lee, Darye;Kim, Choon Young
    • Journal of Nutrition and Health
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    • v.49 no.4
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    • pp.233-240
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    • 2016
  • Purpose: Diabetic complications are a major concern to manage progression of diabetes. Production of advanced glycation end products (AGEs) due to high blood glucose is one of the mechanisms leading to diabetic complications. Multiple pharmacologic AGE inhibitory agents are currently under development, but clinical applications are still limited due to safety issues. Thus, it is necessary to identify a safe anti-glycation agent. It is known that burdock roots have antioxidant, anti-inflammatory, and anti-cancer activities. The objective of the present study was to investigate the inhibitory role of burdock roots on the formation of high glucose-induced glycation of bovine serum albumin (BSA). Methods: In this study, glycation of BSA by glucose, galactose, or fructose at $37^{\circ}C$ for 3 weeks was assessed based on levels of ${\alpha}$-dicarbonyl compounds (early-stage glycation products), fructosamine (intermediate products of glycation), and fluorescent AGEs (late-stage glycation products). In order to compare the inhibitory actions of burdock root extract in AGE formation, aminoguanidine (AG), a pharmacological AGE inhibitor, was used as a positive control. Results: BSA glycation by glucose, fructose, and galatose was dose- and time-dependently produced. Burdock root extract at a concentration of 4 mg/mL almost completely inhibited glucose-induced BSA glycation. The results demonstrate that burdock root extract inhibited AGE formation with an $IC_{50}$ value of 1.534 mg/mL, and inhibitory activity was found to be more effective than the standard anti-glycation agent aminoguanidine. This study identified a novel function of burdock root as a potential anti-glycation agent. Conclusion: Our findings suggest that burdock root could be beneficial for preventing diabetic complications.

Comparison of Form Factors of Liver in ZangFu Diagrams (臟腑圖) before Northern Song Ages and Ones Originated from MingTangZangFuTu (明堂臟腑圖) (북송(北宋) 이전 장부도(臟腑圖)와 명당장부도(明堂臟腑圖)에서 기원한 장부도(臟腑圖)에 나타난 간장(肝臟)의 형태요소의 비교)

  • Jo, Hak-Jun
    • The Journal of Korean Medical History
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    • v.29 no.2
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    • pp.17-33
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    • 2016
  • Objectives : The goal of this paper is to verify the hypothesis that the diagrams of liver from MingTangZangFuTu (明堂臟腑圖) were derived from ZangFu diagrams (臟腑圖) before northern Song Ages. Methods : The difference of form of liver was analyzed by means of 4 factors, e.g. shape, number, veins and a petiole of leafs, in diagrams from YanLuoZiNeiJingTu [煙蘿子內境圖], OuXiFanWuZangTu [歐希範五臟圖], CunZhenTu [存眞圖], MingTangZangFuTu and ones of liver from Taoism and MingTangZangFuTu. Results : Diagrams of whole body and liver from MingTangZangFuTu were first found in ZhenJiuJuYing (鍼灸聚英). Among them, lobed shape was first found in YanLuoZiNeiJingTu (in Wudai [五代]), a petiole in OuXiFanWuZangTu (northern Song Ages) and 7 leafs in WuZangLiuFuTu (五臟六腑圖. from Tang (唐) Ages to early northern Song Ages. unknown author.), one of references of UiBangNyuChwi (醫方類聚) (1455). However, veins of leafs were drawn in no diagrams. Conclusions : In diagrams of liver from MingTangZangFuTu, shape and a petiole of leafs were based on diagrams of ZangFu before northern Song Ages, but 7 leafs came from WuZangLiuFuTu. However, veins of leafs were not derived from any diagrams in same period.

Differential Effects of Family Income on Self-rated Health by Age: Analysis of Seoul Citizens Health Indicators Survey 2001, 2005 (소득수준이 주관적 건강상태에 미치는 영향의 연령대별 차이: 2001, 2005년 서울시민보건지표조사 자료의 분석 결과)

  • Jung, Youn;Oh, Ju-Hwan;Cho, Young-Tae
    • Journal of Preventive Medicine and Public Health
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    • v.40 no.5
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    • pp.381-387
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    • 2007
  • Objectives: This study was conducted in order to determine how the association between socioeconomic position(SEP) and health status changes with age among Seoul residents aged 25 and over. Methods: We utilized the 2001 and 2005 Seoul Citizens Health Indicators Surveys. We used self-rated 'poor' health status as an outcome variable, and family income as an indicator of SEP. In order to characterize the differential effects of socioeconomic position on health by age, we conducted separate multivariate analyses by 10-year age groups, controlling for sociodemographic covariates. In order to assess the relative health inequality across socioeconomic groups, we estimated the Relative Index of Inequality (RII). Results: The risk of 'poor health' is significantly high in low family income groups, and this increased risk is seen at all ages. However, the magnitude of relative socioeconomic inequality in health, as measured by the odds ratio and RII, is not identical across age groups. The difference in health across income groups is small in early adulthood (ages 25-34), but increases with age until relatively late in life (ages 35-64). It then decreases among the elderly population (ages more than 65). When the RII reported in 2005 is compared to that reported in 2001, RII can be seen to have increased across all ages, with the exception of individuals aged 25-34. Conclusions: The magnitude of health inequality is the greatest during mid- to late adulthood (ages 45-64). In addition, health inequalities have worsened between 2001 and 2005 across all age groups after economic crisis.

Mechanical Properties of Early Strength Mortar with Ground Granulated Blast Furnace Slag and Expansive Additive (고로슬래그미분말 및 팽창재를 혼입한 조강형 모르타르의 역학적 특성)

  • Koo, Kyung-Mo;Choi, Jae-Won;You, Byeong-Know;Cha, Wan-Ho;Kang, Bong-Hee
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.2
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    • pp.177-184
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    • 2021
  • In this study, the effects of ground granulated blast furnace slag(GGBFS) and expansive additive(EA) on early strength mortar were examined for the purpose of reducing carbon and improving cement performance. As a result, ealry strength Portland cement(EPC) tended to decrease in flow compared to ordinary Portland cement(OPC), but binder with EPC and GGBFS was possible to obtain higher liquidity than OPC. EPC showed higher compressive strength and shrinkage than OPC. The compressive strength of specimen with EPC and GGBFS was reduced proportionally to the replacement ratio of GGBFS. The replacement ratio of GGBFS above the compressive strength equivalent to OPC was higher under low temperature conditions. The use of GGBFS resulted in high shrinkage compared to OPC, and this characteristic was even greater under low temperature conditions. The shrinkage of specimen with EA was decreased in early ages, but was higher than the OPC in long-term ages.

Instantaneous Compliance and Creep Compliance functions of Early-Age Concrete under Quasi-Instantaneous Loading (준-순간 하중에 의한 초기재령 콘크리트의 순간 및 크리프 컴플라이언스 함수)

  • Oh Byung-Hwan;Choi Seong-Cheol;Park Ho
    • Journal of the Korea Concrete Institute
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    • v.17 no.1 s.85
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    • pp.11-18
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    • 2005
  • In order to accurately assess the stresses occurring in the early-age concrete, a compliance function which can consider the characteristics of early-age concrete is required. Existing compliance functions, however, have the limit that they have been deduced from the data of hardened concrete and therefore, do not take into account the fast development of material properties in early-age concrete. Furthermore, the distinction between instantaneous compliance and creep compliance is not clear in the existing experimental method. The purpose of present study is to propose a compliance function which can describe the rapid change of hardening processes in early-age concrete. To this end, a test method which can estimate the instantaneous compliance without creep effects in the early-age concrete was suggested first. Based on the suggested experimental method, tests on the instantaneous as well as creep compliance were performed using MTS automatic servo-loop test machine. The test results showed that both instantaneous and aging viscoelastic compliance, which are constants in B3 model, were functions in terms of age of concrete especially at early ages. Therefore, the modified compliance function based on B3 model was proposed to provide more realistic prediction on the behavior of early-age concrete. It is expected that the present model allows more realistic evaluation of varying stresses in concrete structures at early ages.

The Properties of Hardened Slag by Alkali and Curing Method (알칼리 첨가 및 양생방법에 따른 슬래그 경화체의 특성)

  • 김원기;소정섭;배동인
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.27-32
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    • 2002
  • In this research influences of type and concentration of alkali activator and curing condition on the hydration, and properties of alkali activated blast furnace slag(AAS) concrete were investigated. Sodium carbonate and sulfate were used as alkali activators and their concentration were 4~10 weight percent with Na$_2$O equivalent to binder. The curing conditions were standard curing using 23$^{\circ}C$ water and activated curing chamber at $65^{\circ}C$. Results show that in case of sodium carbonate addition high early strengths were gained by activation of early hydration, but later strength gained was slight. On the other side sodium sulfate strengths were continuously increased with adding amount and ages. Steam curing activated early hydration so that early strengths were improved but later strengths were similar to standard curing. The strength reduction of AAS mortar with sodium sulfate was less than OPC mortar in 5% sulfuric acid solution so that AAS concrete can be useful for acid-resistance concrete.

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Crack Prevention of Very-Early Strength Latex-Modified Concrete (초속경 라텍스개질 콘크리트의 균열 억제방안)

  • Lee, Bong-Hak;Choi, Pan-Gil
    • Journal of Industrial Technology
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    • v.28 no.A
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    • pp.89-96
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    • 2008
  • An increase in the amount of cracking in repaired concrete bridge decks using VES-LMC(Very Early Strength - Latex Modified Concrete ; below VES-LMC) has been noticed by Yun et al(1). Literature indicates that indeed many concrete bridge decks develop transverse cracking, most developing at early ages(3~7 days), many right after construction. The purpose of this study was to establish prevention of map, transverse and longitudinal cracking in VES-LMC and to provide a control methods for minimizing the occurrence of cracks. The proposed prevention against map and transverse cracking was verified by field applications. VES cement was modified, the unit cement contents was reduced into $360kg/m^3$ from $390kg/m^3$, the maximum size of coarse aggregate was increase into 19mm from 13mm, wire mesh and steel fibers were incorporated in concrete mixture. A series of variable combinations were attempted. As a results, the proposed prevention against map and transverse cracking was verified because no crack were occurred until 90 days after overlay.

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