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Investigation of Linear Viscoelastic Properties of Xanthan-Carob Mixture in Sol and Gel States

  • Yoon, Won-Byong;Gunasekaran, Sundaram
    • Food Science and Biotechnology
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    • v.18 no.3
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    • pp.618-623
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    • 2009
  • Synergistic interactions between xanthan (X) and carob (C) were investigated by studying the linear viscoelastic behavior of X, C, and X/C mixtures at sol and gel states. At the solution state, storage modulus (G') dominates the linear viscoelastic properties of X/C mixtures. The gelation temperature (52 to $57^{\circ}C$) was weakly dependent on the xanthan fraction (${\phi}x$) in the mixture. The ${\phi}x$ also had a strong effect on G' until ${\phi}x=0.5$. The elastic active network concentration (EANC) of X/C gels was estimated from the pseudo-equilibrium modulus. The EANC for systems with ${\phi}x=0.25$, 0.5, 0.75, and 1 at 1% total concentration was 2.3, 4.4, 4.1, and 0.32 (${\times}10^{-3}\;mol/m^3$), respectively. The maximum synergistic effect was observed at about ${\phi}x=0.5$. The G' at the transition state of X/C mixed gel was proportional to ${\omega}^{3/2}$ at ${\omega}$>${\omega}_{tr}$ (the onset transition frequency) compared to the theoretical limit of ${\omega}^{1/2}$.

The Relationship between Clinical Sign and Radiographic Findings in Temporomandibular Disorders (측두하악장애의 임상적 증상과 방사선적 소견과의 관계)

  • Byung-Il Park;Kyung-Soo Han
    • Journal of Oral Medicine and Pain
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    • v.14 no.1
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    • pp.57-66
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    • 1989
  • 66 patients with temporomandibular disorders were selected for experimental group, and 45 normal subjects who were Dental students were selected for control group. Average age of experimental group was 30.5 years, Male to Female ratio was 2 : 3, and their age distribution were teen-ages to seventh decades. Transcranial radiography (TR) with Denar Accurad 100 was used for each group to get the values of width in joint spaces and to investigate the bony changes of articular surfaces and relative condylar position to articular fossa. In addition to TR, clinical interview and routine charting about amount of mandibular movements and occlusal variations were carried out in experimental group. The obtained results were as follows : 1. The mean values of joint space with in control group were 2.15mm to anterior, 2.98mm to superior and 2.29mm to posterior and the value of relative condylar position to the deepest portion of articular fossa was 0.21mm to anterior. In experimental group, those values were 2.01mm, 2.14mm 2.22mm and 0.12mm to posterior in sequence, respectively. Joint spaces in experimental group, therefore, were inclined to decreased, and relative condylar position was inclined to retrude. Joint space in control group showed symmetric condylar position, but in experimental group showed asymmetry. 2. Non-affected joints with no bony changes in experimental group showed the narrowest joint spaces which were thought to manifest the abnormal stress to non-affected side to dysfunctional state of contralateral affected joints. 3. Amount of mandibular movements in experimental group were within normal values in lateral movements and in protrusive movement but in opening movement with or without passive stretch, those were lower than normal values. Frequency of occlusal variation, for example, protrusive posterior contacts, open bite, median line shift to lateral side were inclined to increase with bony changes and with crepitus.

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Characteristics and Applications of Soild State Nuclear Track Detectors -The Detection and Dosimetry of N-Ions by CR-39- (고체비적검출기(固體飛跡檢出器)의 특성(特性)과 그 응용(應用) -CR-39에 의한 질소(窒素)이온 검출(檢出)과 선양측정(線量測定)-)

  • Kang, Yung-Ho;Kim, Do-Sung
    • Journal of Radiation Protection and Research
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    • v.9 no.2
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    • pp.55-60
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    • 1984
  • The optimum etching condition of allyl diglycol carbonate (CR-39) for detecting the 60 MeV N-ions was determined as $70^{\circ}C$, 20% NaOH for 130min, by considering the variations of track density and diameter. Under these conditions, the maximum detectable track density was $1.7{\times}10^7tr/cm^2$. Track densities were linearly increased with increase of the total charge of the incident 60 MeV N-ions. By considering the scattring of N-ions as the Rutherford elastic scattering of point source, the measured relative probability was well consistent with the calculated value. The detection efficiency of CR-39 was in the range of 54-41% for 60 MeV N-ions of 12 nC-100 nC.

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Bioequivalence Approaches for Highly Variable Drugs: Issue and Solution (개체 변이가 큰 약물 (highly variable drug)의 생물학적동등성 시험을 위한 실험설계 및 평가방법)

  • Baek, In-Hwan;Seong, Soo-Hyeon;Kwon, Kwang-Il
    • Korean Journal of Clinical Pharmacy
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    • v.19 no.1
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    • pp.50-60
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    • 2009
  • Highly variable drugs (within-subject variability greater than 30%) have been difficult to meet current regulatory acceptance criteria using a reasonable number of study subjects. In this study, we reviewed previous studies presenting alternative approaches for bioequivalence evaluation of highly variable drugs, and focused on an approach for widening the bioequivalence acceptance limits using within-subject variability. We discussed the suggested five solutions for highly variable drug including the deletion of $C_{max}$ of the bioequivalence criteria, direct expansion of bioequivalence limit, multiple dose studies in steady state, bioequivalence assessment on the metabolite, add-on study, and widening the bioequivalence acceptance limits based on reference variability. The methods for widening of bioequivalence limits based on reference variability are scaled average bioequivalence containing within-subject variability on reference drug (${\sigma}_{WR}$), population bioequivalence derived from total variability on reference drug (${\sigma}_{TR}$) and test drug (${\sigma}_{TT}$), and individual bioequivalence derived from subject by formulation interaction variability (${\sigma}_D$) and within subject variability on reference drug (${\sigma}_{WR}$) and test drug (${\sigma}_{TR}$). To apply these methods, the switching variability (${\sigma}_0$) will have to be set by the regulatory authorities. The proposals of bioequivalence evaluation approach for the highly variable in Korea are presented for both of new drug and reevaluation drug.

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Mental Stress from Animal Experiments: a Survey with Korean Researchers

  • Kang, Minji;Han, AhRam;Kim, Da-eun;Seidle, Troy;Lim, Kyung-Min;Bae, SeungJin
    • Toxicological Research
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    • v.34 no.1
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    • pp.75-81
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    • 2018
  • Animal experiments have been widely conducted in the life sciences for more than a century, and have long been a subject of ethical and societal controversy due to the deliberate infliction of harm upon sentient animals. However, the harmful use of animals may also negatively impact the mental health of researchers themselves. We sought to evaluate the anxiety level of researchers engaged in animal use to analyse the mental stress from animal testing. The State Anxiety Scale of the State-Trait Anxiety Inventory (STAI) was used to evaluate how researchers feel when they conduct animal, as opposed to non-animal, based experiments (95 non-animal and 98 animal testing researchers). The Trait Anxiety Scale of STAI was employed to measure proneness to anxiety, namely the base trait of the researchers. Additionally, the information on sex, age, education, income, and total working periods was collected. While the Trait Anxiety scores were comparable ($41.5{\pm}10.9$ versus $42.9{\pm}10.1$, p = 0.3682, t-test), the State Anxiety scores were statistically significantly higher for animal users than non-animal users ($45.1{\pm}10.7$ versus $41.3{\pm}9.4$, p = 0.011). This trend was consistent for both male and female. Notably, younger animal testers (${\leq}30$ years of age) with less work experience (${\leq}2$ years) and lower income level (${\leq}27,000$ USD) exhibited higher anxiety scores, whereas these factors did not affect the anxiety level of non-animal users. The present study demonstrated that participation in animal experiments can negatively impact the mental health of researchers.

Metabolomics, a New Promising Technology for Toxicological Research

  • Kim, Kyu-Bong;Lee, Byung-Mu
    • Toxicological Research
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    • v.25 no.2
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    • pp.59-69
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    • 2009
  • Metabolomics which deals with the biological metabolite profile produced in the body and its relation to disease state is a relatively recent research area for drug discovery and biological sciences including toxicology and pharmacology. Metabolomics, based on analytical method and multivariate analysis, has been considered a promising technology because of its advantage over other toxicogenomic and toxicoproteomic approaches. The application of metabolomics includes the development of biomarkers associated with the pathogenesis of various diseases, alternative toxicity tests, high-throughput screening (HTS), and risk assessment, allowing the simultaneous acquisition of multiple biochemical parameters in biological samples. The metabolic profile of urine, in particular, often shows changes in response to exposure to xenobiotics or disease-induced stress, because of the biological system's attempt to maintain homeostasis. In this review, we focus on the most recent advances and applications of metabolomics in toxicological research.

Construction of 154kV Intelligent Substation for Verification Test (154kV급 실증시험용 인텔리전트 변전소 구축)

  • Chung, Y.H.;Kim, M.S.;Kim, J.B.;Lee, H.S.;Choi, I.H.;Lee, D.I.
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.456-457
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    • 2006
  • We have carried out the construction of the 154kV intelligent substation with KEPRI. The Intelligent substation is built in Gochang testing facility of KEPCO and consists of electronic instruments for GIS(gas insulated switchgear), digital control panel, remote monitoring and diagnosis system, and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are introduced compared with the instrument transformer of conventional type. Digital control Panel(DCP) replaces the LCP(local control panel) which is drived for mechanical operation. For the monitoring of the condition of GIS and TR, various sensors are used. In this Paper, we mention the synopsis and report the progress state of project.

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Construction of Intelligent Substation for 154kV Class (154kV급 인텔리전트 변전소 구축)

  • Chung, Y.H.;Yang, D.I.;Kim, J.B.;Song, W.P.;Choi, I.H.;Kim, J.H.;Lee, D.I.
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.33-35
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    • 2005
  • We perform intelligent substation construction of 154kV class with KEPRI. The intelligent substation is build in Gochang 765kV testing facility and consists of electronic instruments, digital control panel, remote monitoring and diagnosis system and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are applicable for instrument transformer of conventional type. Digital control panel(DCP) replaces local panel which is drived by mechanical operation. For monitoring condition of GIS and TR, various sensors are used. In this paper, we report the synopsis and the progress state of project.

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Construction of Intelligent Substation for 154kV Class (154kV급 인텔리전트 변전소 구축)

  • Chung, Y.H.;Yang, D.I.;Kim, J.B.;Choi, I.H.;Kim, J.H.;Lee, D.I.
    • Proceedings of the KIEE Conference
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    • 2005.11b
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    • pp.129-130
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    • 2005
  • We perform intelligent substation construction of 154kV class with KEPRI. The intelligent substation is build in Gochang 765kV testing facility and consists of electronic instruments, digital control panel, remote monitoring and diagnosis system, and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are applicable for instrument transformer of conventional type. Digital control panel(DCP) replaces local panel which is drived by mechanical operation. For monitoring rendition of GIS and TR, various sensors are used. In this paper, we report the synopsis and the progress state of project.

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Intelligent Substation Construction of 154kV Class (154kV 인텔리전트 변전소 구축)

  • Kim J B.;Chung Y. H.;Song W. P.;Choi I. H.;Kim J. H.;Lee D. I.;Koh H. S.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.524-526
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    • 2004
  • We perform intelligent substation construction of 154kV class with KEPRI. The intelligent substation is build in Gochang 765kV testing facility and consists of electronic instruments, digital control panel, remote monitoring and diagnosis system, and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are applicable for instrument transformer of conventional type. Digital control panel(UP) replaces local panel which is drived by mechanical operation. For monitoring condition of GIS and TR, various sensors are used. In this paper, we report the synopsis and the progress state of project.

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