• Title/Summary/Keyword: resistance change

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A study on Mechanical Properties of Acrylic-casein Hybrid Resins for Surface Protection (표면 보호용 수용성 Acrylic-casein Hybrid Resin의 합성 및 기계적 물성에 관한 연구)

  • Lee, Joo-Youb;Kim, Ki-Jun
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.4
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    • pp.618-625
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    • 2012
  • In this study, prepared synthesis waterborne acrylic resin and water soluble milk casein resin. And than extent of casein contents in acrylic resin. We measured property of these samples by Lamb leather which is coated by acrylic-casein resins. According to measure data for solvent resistance, WAR resin and Hybrid resins had good property. Among this result knew that increase of casein constant did not influence to big change of hybrid resin property. As test of tensile strength, WAR had lowest strength($1.399kg_f/mm^2$) and WAC-3 had highest strength($1.426kg_f/mm^2$). Also we knew that best property of abrasion was WAC-3(69.774 mg.loss). In elongation case, WAR had best property(820%) in this experiment.

An Experimental Study on Relation between Chloride Diffusivity and Microstructural Characteristics for GGBS Concrete (슬래그 미분말 혼합 콘크리트의 공극구조와 염화물 확산계수와의 관계에 대한 실험적 연구)

  • Kim, Tae-Sang;Jung, Sang-Hwa;Choi, Young-Cheol;Song, Ha-Won
    • Journal of the Korea Concrete Institute
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    • v.21 no.5
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    • pp.639-647
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    • 2009
  • In order to evaluate the durability of reinforced concrete structures under chloride attack from sea water and frost damage, it is important to analyze both the microstructural characteristics of concrete and its diffusion resistance of concrete against chloride ingress. In this study, a relation between micro-pore structures of concrete obtained by the Mercury Intrusion Porosimetry and accelerated chloride diffusivity as well as long term chloride diffusivity were studied for ground granulated blast furnace slag(GGBS) concrete. Different water-cement ratio of 40, 45, 50% and different unit cement concrete of 300, 350, 400 or 450 kg/$m^3$ of the GGBS concrete along with OPC concrete were used and freeze and thawing, and the change in diffusivity and microstructure were observed for both GGBS concrete and damaged GGBS concrete due to rapid freezing and thawing.

Evaluation of CPTU Cone Factor of Silty Soil with Low Plasticity Focusing on Undrained Shear Strength Characteristics (저소성 실트지반의 비배수 전단강도 특성을 고려한 CPTU 콘계수 평가)

  • Kim, Ju-Hyun
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.73-83
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    • 2017
  • Laboratory and in-situ tests were conducted to evaluate the cone factors for the layers with low plasticity containing a lot of silty and sand soils from the west coast (Incheon, Hwaseong and Gunsan areas) and its applicability was evaluated based on these results. The cone factors were evaluated from 19 to 23 based on unconfined compression strengths (qu), from 13 to 13.8 based on simple CU strengths and from 11.6 to 13.1 based on field vane strengths, respectively. The unconfined compression strengths of undisturbed silty soil samples with low plasticity were considerably underestimated due to the change of in-situ residual effective stress during sampling. Half of unconfined compression strength (qu/2) based cone factors of silty soils with low plasticity fluctuated and were approximately 1.8 times higher than simple CU based values of these soils. When evaluating cone factors of these soils, it should be judged overall on the physical properties such as the grain size distribution and soil plasticity and on the fluctuation of the corrected cone resistance and the sleeve friction due to the distribution of sandseam in the ground including pore pressure parameter.

Functional Anaylsis of sprD Gene Encoding Streptomyces griseus Protease D(SGPD) in Streptomyces griseus

  • Choi Si-Sun;Kim Joung-Hoon;Kim Jong-Hee;Kang Dae-Kyung;Kang Sang-Soon;Hong Soon-Kwang
    • Journal of Microbiology and Biotechnology
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    • v.16 no.2
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    • pp.312-317
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    • 2006
  • The chromosomal sprD gene encoding Streptomyces griseus protease D (SGPD), a chymotrypsin-like protease, was disrupted in Streptomyces griseus by insertion of the neomysin-resistance gene. The production of chymotrypsin activity of sprD disruptant was not completely abolished, but delayed by 24 h, compared with that of wild-type strain. The aerial mycelial formation of sprD disruptant was retarded, and specifically the formation of spores was not observed in the central region of colonies. However, normal morphological development into spores was observed in the marginal region of colonies. In addition, the production of yellow pigment that might be dependent on A-factor was also decreased in the sprD disruptant, compared with that of the wild-type strain. Introduction of the sprD gene, which was placed on a high copy-numbered plasmid into S. griseus ${\Delta}sprD$, partially restored the ability of morphological development, and a significant level of sporulation was observed. When the overexpression vector for sprD, pWHM3-D, was introduced in S. griseus, there was no significant change in the chymotrypsin activity or colonial morphology, in contrast to Streptomyces lividans, indicating the presence of a tight regulation system for the overexpression of the sprD gene in S. griseus.

Changes and Meanings of the Images of Female Model on the Cover of Men's Fashion Magazines (남성 패션잡지 표지에 나타난 여성모델 이미지 변화와 의미 분석)

  • Kwon, Jeanne;Yim, Eun-Hyuk
    • Journal of the Korea Fashion and Costume Design Association
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    • v.17 no.2
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    • pp.79-92
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    • 2015
  • Covers of fashion magazines are part of the media that reflects the zeitgeist. Thus an analysis of the covers is a tool to probe the social and cultural changes of a period. This study attempts to shed light on the changes of the image of women on the cover of men's fashion magazines; this study intends to investigate the changes of status and role of women, from the past up to the present, through analyzing the meaning of the image of female models. For this purpose, this study conducts both literature and corroborative research. The period for the analysis is limited to post-1960s when female models began to appear alone on the cover of men's fashion magazine. The three decades from the 1960s through today have been analyzed according to its characteristics. The result is as follows: female models in the 1960s were shown as subjugated and ancillary to men as a commodity for the affluent materialistic civilization after World War II. In the 1970s, thanks to feminism movement, the image of resistance dominated. As a result of women's right movement, the 1980s came to witness the female image of subjective characteristics. Finally, starting in the 1990s, a mixture of subjugated, resistant, and subjective image of female models has appeared. In the contemporary culture, where the communication through images is being increased, the image of the female models in fashion magazines could work as a criterion to measure the social change.

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A Study of Proprioceptive Neuromuscular Facilitation Principles (고유수용성 신경근 촉진법 원리에 관한 고찰)

  • Bae Sung-Soo
    • The Journal of Korean Physical Therapy
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    • v.5 no.1
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    • pp.109-114
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    • 1993
  • The originator of the proprioceptive neuromuscular facilitation method was Dr. Herman Kabat, a man who received the bachelor of science degree from New York University in 1932. In 1936 he moved to the University of Minnesota where he served as instructor in physiology and also studies medicine. He received his medical doctorate in 1942. When Dr. Karbat meet Sister Kenny suggested that certain change. She does not receptive his ideas. So that he decided to pursure the treatment of patients. Upon the establishment of the Karbat- kaiser Institute to be opened in 1946. Margaret Knott, the first physical therapist to be employed by him and to become his head physical therapist. In 1948 Vallejo center was opened. Dr. Kabat developed the PNF method combined motions to ascertain the effectiveness of maximal resistance and stretch in facilitating the response of a weak distal muscle. He identified mass movement patterns that were spiral and diagonal in character in 1965. Margaret Knott presented lecture at tile APTA Annual Conference in Las Vegas. The title was In the groove. On December 18, 1978 she passed away at her home in Vallejo. Marie-Louise Mangold is director of the Kaiser Foundation Rehabilitation Center now. She is the Vice President of International Proprioceptive Neuromuscular facilitation Association. About 20 physical therapist working teaching and study at KFRC in Vallejo. PNF neuromuscular mechanism becomes integrated and efficient without awareness of individual muscle action, reflex and a multitude of other neurophysiological reactions. The principles of PNF are visual consideration, verbal consideration, and proprioceptive input consideration with tactile stimulation, joint receptors, appropriate facilitation, stretch reflex normal timing, irradiation, pattern of movement.

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Growth mechanism of three dimensionally structured TiO2 thin film for gas sensors (가스 감응용 3차원 구조체 TiO2 박막 성장기구)

  • Moon, Hi-Gyu;Yoon, Seok-Jin;Park, Hyung-Ho;Kim, Jin-Sang
    • Journal of Sensor Science and Technology
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    • v.18 no.2
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    • pp.110-115
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    • 2009
  • Polystyrene (PS) microspheres were used to good advantage as a template material to prepare macroporous $TiO_2$ thin films. This is enabled to run the thermal decomposition of the PS without the collapsing of the 3-D macroporous framework during the calcination step. $TiO_2$ thin films were deposited onto the colloidal templated substrates at room temperature by RF sputtering, and then samples were thermally treated at $450^{\circ}C$ for 40.min in air to remove the organic colloidal template and induce crystallization of the $TiO_2$ film. The macroporous $TiO_2$ thin film exhibited a quasi-ordered partially hexagonal close-packed structure. Burst holes, estimated to be formed during PS thermal decomposition, are seen as the hemisphere walls. the inner as well as the outer surfaces of the hollow hemispheres formed by the method of thermal decomposition can be easily accessed by the diffusing gas species. As a consequence, the active surface area interacting with the gas species is expected to be enlarged about by a factor of fourth as large as compared to that of a planar films. Also the thickness at neighboring hemisphere could be controlled a few nm thickness. If the acceptor density becomes as large that depletion width reaches those thickness, the device is in the pinch off-situation and a strong resistance change should be observed.

Effects of Uwhangchungsimwon(牛黃淸心元) on Cerebral Blood Flow and Systemic Blood Pressure in Humans (우황청심원이 정상인의 뇌혈류 및 혈압에 미치는 영향)

  • Kim, Young-Suk
    • The Journal of Internal Korean Medicine
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    • v.20 no.1
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    • pp.222-231
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    • 1999
  • Uwhangchungsimwon(UC) has been used in the treatment of a wide variety of conditions including stroke, hypertension, arteriosclerosis, autonomic imbalance, mental instablity, etc in Korean traditional hospitals, In particular it is often initialy chosen for emergency care of acute stroke. The aim of this study was to evaluate the effect of UC on cerebral hemodynamics. Using transcranial Doppler ultrasound, we studied changes of mean flow velocity and pulsatility index(PI) of middle cerebral arteries (MCAs) from 11 health young volunteers who were administrated with 1 pill UC and 11 health controls who were not. We obtained hypercapnia with breath-holding and evaluated cerebrovascular reactivity with breath-holding index(BHI). Systolic blood pressure, diastolic blood pressure, and heart rate were measured using ambulatory blood pressure monitoring(ABPM). In UC administration group, the evaluation was performed during basal condition. and repeated at 20, 40, and 60 min after administration. In controls, the evaluation was performed at corresponding time intervals. Mean flow velocity in middle cerebral artery, systolic blood pressure, diastolic blood pressure, and heart rate did not change during the observation period and were not different between these two groups. However, administration of UC was associated with decreases in PI by $3.6{\sim}12.4%$ in BHI by $17.9{\sim}24.8%$ compared with pre-administration period. Decreases in PI and BHI with UC were significantly different compared with control group (p<0.05). These results indicate that UC decreases PI and BHI in cerebral artery, which is due to a dilation of cerebral resistance vessels.

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Effect of Farnesyltransferase Inhibitor R115777 on Mitochondria of Plasmodium falciparum

  • Ha, Young Ran;Hwang, Bae-Geun;Hong, Yeonchul;Yang, Hye-Won;Lee, Sang Joon
    • Parasites, Hosts and Diseases
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    • v.53 no.4
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    • pp.421-430
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    • 2015
  • The parasite Plasmodium falciparum causes severe malaria and is the most dangerous to humans. However, it exhibits resistance to their drugs. Farnesyltransferase has been identified in pathogenic protozoa of the genera Plasmodium and the target of farnesyltransferase includes Ras family. Therefore, the inhibition of farnesyltransferase has been suggested as a new strategy for the treatment of malaria. However, the exact functional mechanism of this agent is still unknown. In addition, the effect of farnesyltransferase inhibitor (FTIs) on mitochondrial level of malaria parasites is not fully understood. In this study, therefore, the effect of a FTI R115777 on the function of mitochondria of P. falciparum was investigated experimentally. As a result, FTI R115777 was found to suppress the infection rate of malaria parasites under in vitro condition. It also reduces the copy number of mtDNA-encoded cytochrome c oxidase III. In addition, the mitochondrial membrane potential (${\Delta}{\Psi}m$) and the green fluorescence intensity of MitoTracker were decreased by FTI R115777. Chloroquine and atovaquone were measured by the mtDNA copy number as mitochondrial non-specific or specific inhibitor, respectively. Chloroquine did not affect the copy number of mtDNA-encoded cytochrome c oxidase III, while atovaquone induced to change the mtDNA copy number. These results suggest that FTI R115777 has strong influence on the mitochondrial function of P. falciparum. It may have therapeutic potential for malaria by targeting the mitochondria of parasites.

Stimulation of Insulin Secretion by Silk Fibroin Hydrolysate in Streptozotocin-induced Diabetic Rats and db/db Mice (Streptozotocin 당뇨유발 쥐와 db/db 마우스에서의 피브로인 가수분해물에 의한 인슐린 분비 촉진)

  • Park, Kum-Ju;Hong, Seong-Eui;Do, Myoung-Sool;Hyun, Chang-Kee
    • Korean Journal of Pharmacognosy
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    • v.33 no.1 s.128
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    • pp.21-28
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    • 2002
  • Antidiabetic effects of the acid hydrolysate of silk fibroin were investigated by oral administration to animal models for diabetes mellitus, Fibroin protein was extracted from cocoon and digested to peptides of low-molecular weight range (mainly below 3,000) and amino acids by acid hydrolysis, Feeding of the fibroin hydrolysate resulted in a significant recovering effect on reduction of body weight gain and a lowering effect on blood glucose gain in streptozotocin-induced diabetic Sprague Dawley rats (STZ rats) which were used as an insulin-dependent diabetic animal model. But the body weight and blood glucose level in C57BL/KsJ-db/db mice (db/db mice), an non-insulin-dependent diabetic animal model, were not changed significantly by the feeding, On the other hand, plasma leptin levels increased according to increased feeding amount of the hydrolysate in STZ rats and db/db mice in common, It was concluded from the results that the fibroin hydrolysate might stimulate the insulin secretion by recovering or activating pancreatic ${\beta}$ cells and result in the increased plasma leptin level. It was also deduced that the antidiabetic improvements in body weight and blood glucose gain in STZ were thought to be due to the increased insulin secretion, but in db/db mice of which the diabetic symptoms were caused by insulin resistance, the stimulated secretion of insulin was unlikely to be able to change body weight and blood glucose level significantly.