• Title/Summary/Keyword: resistance changes

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Effects of Elastic Band Resistance Exercise Program in the Falls Prevention of Elderly Women (탄력밴드를 이용한 저항운동프로그램이 여성노인의 낙상예방에 미치는 효과)

  • Noh, Hyun-Jeong;Kim, Seok-Hwan;Kim, Tea-Yoon;Song, Myung-Soo
    • PNF and Movement
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    • v.11 no.2
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    • pp.57-65
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    • 2013
  • Purpose : This purpose of this study was to investigate the effects of elastic band resistance exercise program in the falls prevention of elderly women. Methods : The subjects of this study, 46 people elderly women who participated in the exercise program of Jeollanamdo Y elderly welfare center were chosen as subjects and use the elastic band resistance exercise program for 12 weeks. Results : There was a significant increase on the physical function and fall efficacy of all the subjects in the experimental group and the control one after the experiment. Furthermore, the experimental group showed more meaningful improvement than the control one. Conclusion : Falls Efficacy of the experimental group before the experiment, after the changes in difference was noted. More results from the 12 weeks of using the elastic band resistance exercise program to increase the efficacy of body functions (power of lower extremity, muscle endurance, flexibility, balance, and agility), and falls efficacy of elderly women is considered as an effective fall prevention exercise program.

Structural health monitoring of CFRPs using electrical resistance by reduced peripheral electrodes

  • Park, Young-Bin;Roh, Hyung Doh;Lee, In Yong
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.737-744
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    • 2021
  • In this study, structural health monitoring (SHM) methods of carbon fiber reinforced plastics (CFRPs) were investigated using electrical resistance. The developed sensing technique monitored electrical resistance in accordance with the impact damage of a CFRP. The changes in electrical resistances with multiple electrode sets enabled SHM without extra sensors so that this technique can be called self-sensing. Moreover, this study proposed electrodes only at peripheral side of a structure to minimize the number of electrodes compared to those in an array which has square number of sensors as the sensing area increases. For the intensive investigation, electromechanical sensitivity in terms of electrode distance was analyzed and optimized under drop weight impact testing. Then, SHM methods with electrodes in an array and electrodes in peripheral edges were comparatively investigated. The developed methods successfully localized impact damages into 2D coordinates. Furthermore, damage severity can be shown with a damage map by calculating electrical resistance change ratio. Therefore, structural health self-sensing system using electrical resistance was successfully developed with the minimum number of electrodes.

gyrA Mutations Found Among Ofloxacin-resistant Mycobacterium tuberculosis is Isolated from Korea

  • Kim Junho;Kim Yeun;Bae Kiho;Song Taek-Sun;Cho Sang-Nae;Lee Hyeyoung
    • Biomedical Science Letters
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    • v.11 no.4
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    • pp.465-471
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    • 2005
  • Ofloxacin has antimycobacterial activity that possibly contributes a pivotal role in the second-line drug regimens that are used for the treatment of multidrug-resistant tuberculosis. However, in some communities, the resistance rate of Mycobacterium tuberculosis to this agent is surging. Therefore, a rapid and accurate method that can be used to determine the resistance of M tuberculosis to the ofloxacin can be very useful for effective treatment of the patients. As an effort to develop such a method, this study was set up to reveal general types of mutations that are related to ofloxacin resistance of M tuberculosis. From previous studies, it has been well known that ofloxacin resistance is associated with mutations in a gene encoding the gyrase A subunit protein. In this study, we obtained 43 ofloxacin-resistant and 50 ofloxacin-susceptible M tuberculosis clinical isolates from Masan National TB Hospital, and sequences of DNA fragment of 320 bp, region of gyrA corresponding to the ofloxacin resistance-determining region were analyzed. In brief, the results showed that a total of seven mutation types were found at gyrA. Theses mutations were all clustered within nucleotides 2574 to 2586 of the gyrA gene (codons 88 to 94). Codon 94 was the most frequently substituted site. Twenty-four of the 43 isolates had mutations at this position resulting in a total of five different types of amino acid changes $(Asp{\to}Ala,\;Asp{\to}Gly,\;Asp{\to}His,\;Asp{\to}Tyr,\;and\;Asp{\to}Asn)$. Five isolates contained a mutation at codon 90 resulting $Ala{\to}Val$ change. Four isolates had mutations at codon 91 causing a $Ser{\to}Pro$ change at this site. Two isolates contained a mutation at codon 88 and each of them resulted in different types of amino acid changes $(Gly{\to}Cys,\;Gly{\to}Ala)$. On the other hand, polymorphic site at codon 95 was found in both ofloxacin-resistant and ofloxacin-susceptible isolates. From these results, we concluded that the rate of mutations present in gyrA among ofloxacin-resistant M. tuberculosis in Korea is similar to the general rates of mutations found throughout the world. Subsequently, an oligonucleotide probe was designed based on the results of sequence analysis and was used to develop a dot blot hybridization assay system to determine ofloxacin-resistance of M tuberculosis. To evaluate this probe, dot-blot hybridization was carried out using other 57 clinical isolates, and the results showed that the dot-blot hybridization assay is good for detecting sequence alterations atgyrA gene.

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Shear resistance behaviors of a newly puzzle shape of crestbond rib shear connector: An experimental study

  • Chu, Thi Hai Vinh;Bui, Duc Vinh;Le, Van Phuoc Nhan;Kim, In-Tae;Ahn, Jin-Hee;Dao, Duy Kien
    • Steel and Composite Structures
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    • v.21 no.5
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    • pp.1157-1182
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    • 2016
  • A newly puzzle shape of crestbond rib shear connector is a type of ductile perfobond rib shear connector. This shear connector has some advantages, including relatively easy rebar installation and cutting, as well as the higher shear resistance strength. Thus, this study proposed a newly puzzle shape of crestbond rib with a "${\mho}$" shape, and its shear resistance behaviors and shear strengths were examined using push-out tests. Five main parameters were considered in the push-out specimens to evaluate the effects of shear resistance parameters such as the dimensions of the crestbond rib, transverse rebars in the crestbond dowel, concrete strength, rebar strength, and dowel action on the shear strength. The shear loading test results were used to compare the changes in the shear behaviors, failure modes, and shear strengths. It was found that the concrete strength and number of transverse rebars in the crestbond rib were significantly related to its shear resistance. After the initial bearing resistance behavior of the concrete dowel, a relative slip occurred in all the specimens. However, its rigid behavior to shear loading decreased the ductility of the shear connection. The cross-sectional area of the crestbond rib was also shown to have a minor effect on the shear resistance of the crestbond rib shear connector. The failure mechanism of the crestbond rib shear connector was complex, and included compression, shear, and tension. As a failure mode, a crack was initiated in the middle of the concrete slab in a vertical direction, and propagated with increasing shear load. Then, horizontal cracks occurred and propagated to the front and rear faces of the specimens. Based on the results of this study, a design shear strength equation was proposed and compared with previously suggested equations.

A Study of Resistance to Change by Organizational Politics and Fairness in The Split-offs Firms (분할 기업에서 조직정치지각과 공정성에 따른 변화저항 연구)

  • Kim, Sung Gun;Jung, Byoungho;Kim, Joongwha
    • Journal of Digital Convergence
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    • v.16 no.4
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    • pp.55-67
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    • 2018
  • The organizational politics strengthened resistance to change. This study explores how the organizational political perception and fairness in split firms affect resistance to change. The analysis showed that the boss's and colleague's politics is minimized by its distributional fairness and procedural fairness. The organizational politics strengthened resistance to change. Additionally, mediating effects of fairness were analyzed. As a result, it was revealed that the perception of organized politics by bosses and that colleagues' perception of organizational politics affected resistance to change based on distributional fairness. However, it was shown that procedural fairness had no mediating roles between organizational politics and change resistance. There is a need to pay keen attention to distributional fairness to minimize the resistance to changes of organizational members at the split. If distributional fairness is not secure, Members will be a political behavior.

Suppression of UDP-glycosyltransferase-coding Arabidopsis thaliana UGT74E2 Gene Expression Leads to Increased Resistance to Psuedomonas syringae pv. tomato DC3000 Infection

  • Park, Hyo-Jun;Kwon, Chang-Seob;Woo, Joo-Yong;Lee, Gil-Je;Kim, Young-Jin;Paek, Kyung-Hee
    • The Plant Pathology Journal
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    • v.27 no.2
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    • pp.170-182
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    • 2011
  • Plants possess multiple resistance mechanisms that protect themselves against pathogen attack. To identify unknown components of the defense machinery in Arabidopsis, gene-expression changes were monitored in Arabidopsis thaliana under 18 different biotic or abiotic conditions using a DNA microarray representing approximately 25% of all Arabidopsis thaliana genes (www.genevestigator.com). Seventeen genes which are early responsive to salicylic acid (SA) treatment as well as pathogen infection were selected and their T-DNA insertion mutants were obtained from SALK institute. To elucidate the role of each gene in defense response, bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 was inoculated onto individual T-DNA insertion mutants. Four mutants exhibited decreased resistance and five mutants displayed significantly enhanced resistance against Pst DC3000-infection as measured by change in symptom development as compared to wild-type plants. Among them, member of uridin diphosphate (UDP)-glycosyltransferase (UGT) was of particular interest, since a UGT mutant (At1g05680) showed enhanced resistance to Pst-infection in Arabidopsis. In systemic acquired resistance (SAR) assay, this mutant showed enhanced activation of SAR. Also, the enhanced SAR correlated with increased expression of defense-related gene, AtPR1. These results emphasize that the glycosylation of UGT74E2 is a part of the SA-mediated disease-resistance mechanism.

Effect of Insulin Resistance on the Metabolism of Periparturient Dairy Cattle (분만전후기 젖소에서 insulin resistance의 대사적 작용)

  • Kim, Jin-Wook
    • Journal of agriculture & life science
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    • v.44 no.5
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    • pp.65-74
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    • 2010
  • Dairy cow undergoes major adaptations in glucose and lipid metabolism to meet fetal and mammary nutrient requirements during the periparturient period. These adaptations are characterized by major changes in response to the homeostatic signal of insulin. In response to insulin, fatty acids are mobilized to meet energy demand. And cow develop insulin resistance during the late prepartum period to facilitate glucose sparing for the fetus and mammary gland. Insulin resistance is an important adaptation and may be partly responsible for the large increase in plasma nonesterified fatty acid (NEFA) that occurs prior to parturition and coincides with the characteristic decrease in dry matter intake (DMI). Modulation of insulin resistance by administration of thiazolidinedione (TZD) during the periparturient period, likely through the activation of $PPAR{\gamma}$, has substantial potential to minimize energy and immune-related metabolic disorders, and thus may result in increased productivity and improved health of dairy cows.

Influence of the cathode catalyst layer thickness on the behaviour of an air breathing PEM fuel cell

  • Ferreira-Aparicio, Paloma;Chaparro, Antonio M.
    • Advances in Energy Research
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    • v.2 no.2
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    • pp.73-84
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    • 2014
  • Fuel cells of proton exchange membrane type (PEMFC) working with hydrogen in the anode and ambient air in the cathode ('air breathing') have been prepared and characterized. The cells have been studied with variable thickness of the cathode catalyst layer ($L_{CL}$), maintaining constant the platinum and ionomer loads. Polarization curves and electrochemical active area measurements have been carried out. The polarization curves are analyzed in terms of a model for a flooded passive air breathing cathode. The analysis shows that $L_{CL}$ affects to electrochemical kinetics and mass transport processes inside the electrode, as reflected by two parameters of the polarization curves: the Tafel slope and the internal resistance. The observed decrease in Tafel slope with decreasing $L_{CL}$ shows improvements in the oxygen reduction kinetics which we attribute to changes in the catalyst layer structure. A decrease in the internal resistance with $L_{CL}$ is attributed to lower protonic resistance of thinner catalyst layers, although the observed decrease is lower than expected probably because the electronic conduction starts to be hindered by more hydrophilic character and thicker ionomer film.

Fire resistance and residual strength of reactive powder concrete Using metakaolin

  • Jang, Hongseok;Yi, Jebang;So, Seungyoung
    • Steel and Composite Structures
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    • v.36 no.6
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    • pp.657-669
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    • 2020
  • This study investigates the fire resistance characteristics of reactive powder concrete according to changes in the cement content per unit area, mixing ratio of metakaolin (MK), and content of polypropylene fiber. A fire test was conducted, and the resulting residual strength characteristics were investigated through flexural and compressive strength measurements, as well as condition rating classification based on visual evaluation. MK effectively reduced the initial high content of calcium hydroxide, thereby reducing the water vapor pressure generated during pyrolysis and slowing spalling. Furthermore, the pore structure and loose tissue were effective for relieving the water vapor pressure in the event of a fire.

A Study on AC/DC Converter Design of High Efficiency for Inverter Resistance Welder (인버터 저항용접기의 전력효율 향상을 위한 AC/DC 컨버터 설계에 관한 연구)

  • Kwak, D.K.;Jung, W.S.;Kang, W.C.
    • Proceedings of the KIPE Conference
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    • 2016.07a
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    • pp.40-41
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    • 2016
  • The inverter resistance welder requires AC/DC converter of high efficiency because the converter changes a commercial ac power source to low voltage dc power source. Harmonic components that occur in the conversion process of converter decrease system power factor and deal great damage in electric power system. To improve such problems, this paper proposes a high efficiency AC/DC converter for inverter resistance welder. The switching devices in the proposed converter are operated by soft switching technique using a new quasi-resonant circuit. As a result, the proposed AC/DC converter obtains low switching power loss and high efficiency.

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