• Title/Summary/Keyword: Use-dependence

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Inhibition of voltage-dependent K+ channels by antimuscarinic drug fesoterodine in coronary arterial smooth muscle cells

  • Park, Seojin;Kang, Minji;Heo, Ryeon;Mun, Seo-Yeong;Park, Minju;Han, Eun-Taek;Han, Jin-Hee;Chun, Wanjoo;Park, Hongzoo;Park, Won Sun
    • The Korean Journal of Physiology and Pharmacology
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    • v.26 no.5
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    • pp.397-404
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    • 2022
  • Fesoterodine, an antimuscarinic drug, is widely used to treat overactive bladder syndrome. However, there is little information about its effects on vascular K+ channels. In this study, voltage-dependent K+ (Kv) channel inhibition by fesoterodine was investigated using the patch-clamp technique in rabbit coronary artery. In whole-cell patches, the addition of fesoterodine to the bath inhibited the Kv currents in a concentration-dependent manner, with an IC50 value of 3.19 ± 0.91 μM and a Hill coefficient of 0.56 ± 0.03. Although the drug did not alter the voltage-dependence of steady-state activation, it shifted the steady-state inactivation curve to a more negative potential, suggesting that fesoterodine affects the voltage-sensor of the Kv channel. Inhibition by fesoterodine was significantly enhanced by repetitive train pulses (1 or 2 Hz). Furthermore, it significantly increased the recovery time constant from inactivation, suggesting that the Kv channel inhibition by fesoterodine is use (state)-dependent. Its inhibitory effect disappeared by pretreatment with a Kv 1.5 inhibitor. However, pretreatment with Kv2.1 or Kv7 inhibitors did not affect the inhibitory effects on Kv channels. Based on these results, we conclude that fesoterodine inhibits vascular Kv channels (mainly the Kv1.5 subtype) in a concentration- and use (state)-dependent manner, independent of muscarinic receptor antagonism.

Formalizing the Role of Social Capital on Individuals' Continuous Use of Social Networking Sites from a Social Cognitive Perspective

  • Guo, Yu;Li, Yiwei;Ito, Naoya
    • Asian Journal for Public Opinion Research
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    • v.1 no.2
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    • pp.90-102
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    • 2014
  • By integrating useful insights from social cognitive theory and social capital theory, we aim to develop a model for better understanding people's behaviors related to the use of social networking sites (SNSs) and formalize the role of social capital in individuals' continuous SNS use. Propositions that emphasize the triadic interactive relationships among environmental, personal, and behavioral factors were highlighted in this study. After reviewing previous studies, in this paper we proposed the following: (1) the causation between SNS use and individuals' perceived social capital might be mutual; social capital may not only be the result of media selectivity, but could also be an essential stimulus initiating the start of using SNSs; (2) the influences of SNSs use on the generation of individuals' online social capital might be conditional upon particular patterns of use; (3) both the level of dependence on SNSs and the differentiated patterns of SNSs use vary according to individuals' perceived offline social capital and their personal characteristics, for instance, personality or self-construal, and social anxiety.

The Effects of College Students' Dual Use of Electronic Cigarette and Conventional Cigarette on Depression (대학생 중복흡연이 우울에 미치는 영향)

  • Kim, Hee Jin;Lee, Bokim;Song, Min Kyung;Lee, Jinhwa
    • Research in Community and Public Health Nursing
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    • v.32 no.2
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    • pp.186-194
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    • 2021
  • Purpose: This study was conducted to find out the association between dual-use of the electronic cigarette (EC) and conventional cigarette (CC) and depression among undergraduate students. Methods: The participants of this study were 225 undergraduate students who were attending two universities located in Ulsan metropolitan city. Descriptive statistics and multiple regression were conducted to analyze the data. Results: Nicotine dependence and depression were significantly higher in the dual-use group than in the single-use group. Dual-use of the EC and CC was significantly associated with depression among undergraduate students. In addition, quality of sleep was significantly associated with depression among undergraduate students. Conclusion: In order to prevent depression among undergraduate students, it is necessary to improve the awareness of the danger of dual use of the EC and CC.

Design of Spherical Aberration Free Aspherical Lens by Use of Ray Reverse Tracing Method (광선 역추적 방식을 이용한 구면수차 제거 비구면 렌즈의 설계)

  • 김한섭;박규열;이원규;전종업
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.10
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    • pp.191-198
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    • 2003
  • In this study, aberration free aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, especially spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.

The Improved Success Rate of Integer Ambiguity Resolution by Using Many Visible GPS/GNSS Satellites

  • Kondo, Kentaro
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.243-246
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    • 2006
  • This study investigates the improvement in the theoretical success rate of the integer ambiguity resolution in GPS/GNSS carrier-phase positioning by using many visible satellites. It estimates the dependence of the rate on the baseline length in relative positioning under the condition of the use of double/triple-frequency navigation signals. The calculation results show that the use of 14 navigation satellites (i.e., seven GPS and seven Galileo ones) remarkably improves the success rate under the condition of very short baseline length, compared with the use of seven GPS ones. The numerical reliability of the calculated success rates is strictly tested by examining the tightness of the union and minimum-distance bounds to the rate. These bounds are also shown to be effective to investigate the realization of the high success rates.

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Influence of Smartphone usage Types and Excessive Expectation for Smartphone on Adolescents' Smartphone Overdependence (스마트폰 사용유형과 스마트폰에 대한 과도한 기대가 청소년의 스마트폰 과의존에 미치는 영향)

  • Bae, Sung-Man
    • Informatization Policy
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    • v.25 no.4
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    • pp.65-83
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    • 2018
  • This study examined the effects of smartphone usage types and excessive expectation for smartphone on adolescents' smartphone overdependence. It utilized the data of 3,454 adolescents (1,758 males and 1,696 females), aged between 13 and 19 from a smartphone overdependence survey of the National Information Society Agency. As a result of the hierarchical multiple regression analysis, age and household income had a negative effect on smartphone overdependence. Weekly smartphone usage time positively affected the serious consequences (sub-factor of smartphone overdependence). Among the different types of smartphone usage, information seeking, SNS, gaming, and the excessive expectation for smartphones had positive impact on smartphone overdependence. Smartphone usage for leisure seeking did not affect smartphone overdependence, but it negatively influenced serious consequences. Messenger use did not affect smartphone overdependence, but the use had a positive effect on salience, and a negative effect on serious consequences. The results of this study suggest that it is necessary to identify the types of smartphone use as well as the usage time to understand the smartphone dependence of adolescents. In addition, it seems necessary to recognize and correct the irrational excessive expectation for smartphone in order to prevent dependence and implement effective interventions.

A Study on Startups' Dependence on Business Incubation Centers (창업보육서비스에 따른 입주기업의 창업보육센터 의존도에 관한 연구)

  • Park, JaeSung;Lee, Chul;Kim, JaeJon
    • Korean small business review
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    • v.31 no.2
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    • pp.103-120
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    • 2009
  • As business incubation centers (BICs) have been operating for more than 10 years in Korea, many early stage startups tend to use the services provided by the incubating centers. BICs in Korea have accumulated the knowledge and experience in the past ten years and their services have been considerably improved. The business incubating service has three facets : (1) business infrastructure service, (2) direct service, and (3) indirect service. The mission of BICs is to provide the early stage entrepreneurs with the incubating service in a limited period time to help them grow strong enough to survive the fierce competition after graduating from the incubation. However, the incubating services sometimes fail to foster the independence of new startup companies, and raise the dependence of many companies on BICs. Thus, the dependence on BICs is a very important factor to understand the survival of the incubated startup companies after graduation from BICs. The purpose of this study is to identify the main factors that influence the firm's dependence on BICs and to characterize the relationships among the identified factors. The business incubating service is a core construct of this study. It includes various activities and resources, such as offering the physical facilities, legal service, and connecting them with outside organizations. These services are extensive and take various forms. They are provided by BICs directly or indirectly. Past studies have identified various incubating services and classify them in different ways. Based on the past studies, we classify the business incubating service into three categories as mentioned above : (1) business infrastructure support, (2) direct support, and (3) networking support. The business infrastructure support is to provide the essential resources to start the business, such as physical facilities. The direct support is to offer the business resources available in the BICs, such as human, technical, and administrational resources. Finally, the indirect service was to support the resource in the outside of business incubation center. Dependence is generally defined as the degree to which a client firm needs the resources provided by the service provider in order to achieve its goals. Dependence is generated when a firm recognizes the benefits of interacting with its counterpart. Hence, the more positive outcomes a firm derives from its relationship with the partner, the more dependent on the partner the firm must inevitably become. In business incubating, as a resident firm is incubated in longer period, we can predict that her dependence on BICs would be stronger. In order to foster the independence of the incubated firms, BICs have to be able to manipulate the provision of their services to control the firms' dependence on BICs. Based on the above discussion, the research model for relationships between dependence and its affecting factors was developed. We surveyed the companies residing in BICs to test our research model. The instrument of our study was modified, in part, on the basis of previous relevant studies. For the purposes of testing reliability and validity, preliminary testing was conducted with firms that were residing in BICs and incubated by the BICs in the region of Gwangju and Jeonnam. The questionnaire was modified in accordance with the pre-test feedback. We mailed to all of the firms that had been incubated by the BICs with the help of business incubating managers of each BIC. The survey was conducted over a three week period. Gifts (of approximately ₩10,000 value) were offered to all actively participating respondents. The incubating period was reported by the business incubating managers, and it was transformed using natural logarithms. A total of 180 firms participated in the survey. However, we excluded 4 cases due to a lack of consistency using reversed items in the answers of the companies, and 176 cases were used for the analysis. We acknowledge that 176 samples may not be sufficient to conduct regression analyses with 5 research variables in our study. Each variable was measured through multiple items. We conducted an exploratory factor analysis to assess their unidimensionality. In an effort to test the construct validity of the instruments, a principal component factor analysis was conducted with Varimax rotation. The items correspond well to each singular factor, demonstrating a high degree of convergent validity. As the factor loadings for a variable (or factor) are higher than the factor loadings for the other variables, the instrument's discriminant validity is shown to be clear. Each factor was extracted as expected, which explained 70.97, 66.321, and 52.97 percent, respectively, of the total variance each with eigen values greater than 1.000. The internal consistency reliability of the variables was evaluated by computing Cronbach's alphas. The Cronbach's alpha values of the variables, which ranged from 0.717 to 0.950, were all securely over 0.700, which is satisfactory. The reliability and validity of the research variables are all, therefore, considered acceptable. The effects of dependence were assessed using a regression analysis. The Pearson correlations were calculated for the variables, measured by interval or ratio scales. Potential multicollinearity among the antecedents was evaluated prior to the multiple regression analysis, as some of the variables were significantly correlated with others (e.g., direct service and indirect service). Although several variables show the evidence of significant correlations, their tolerance values range between 0.334 and 0.613, thereby demonstrating that multicollinearity is not a likely threat to the parameter estimates. Checking some basic assumptions for the regression analyses, we decided to conduct multiple regression analyses and moderated regression analyses to test the given hypotheses. The results of the regression analyses indicate that the regression model is significant at p < 0.001 (F = 44.260), and that the predictors of the research model explain 42.6 percent of the total variance. Hypotheses 1, 2, and 3 address the relationships between the dependence of the incubated firms and the business incubating services. Business infrastructure service, direct service, and indirect service are all significantly related with dependence (β = 0.300, p < 0.001; β = 0.230, p < 0.001; β = 0.226, p < 0.001), thus supporting Hypotheses 1, 2, and 3. When the incubating period is the moderator and dependence is the dependent variable, the addition of the interaction terms with the antecedents to the regression equation yielded a significant increase in R2 (F change = 2.789, p < 0.05). In particular, direct service and indirect service exert different effects on dependence. Hence, the results support Hypotheses 5 and 6. This study provides several strategies and specific calls to action for BICs, based on our empirical findings. Business infrastructure service has more effect on the firm's dependence than the other two services. The introduction of an additional high charge rate for a graduated but allowed to stay in the BIC is a basic and legitimate condition for the BIC to control the firm's dependence. We detected the differential effects of direct and indirect services on the firm's dependence. The firms with long incubating period are more sensitive to indirect service positively, and more sensitive to direct service negatively, when assessing their levels of dependence. This implies that BICs must develop a strategy on the basis of a firm's incubating period. Last but not least, it would be valuable to discover other important variables that influence the firm's dependence in the future studies. Moreover, future studies to explain the independence of startup companies in BICs would also be valuable.

The Effect of Social Media Use Intensity on Reliance of EWOM and Acceptance of EWOM (항공사 소셜 미디어 이용 강도가 온라인 구전 의존도와 온라인 구전 수용에 미치는 영향)

  • Seo, Eun Ju;Park, Jin-Woo
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.25 no.3
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    • pp.1-8
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    • 2017
  • As many people all over the world increasingly take more time in exchanging with other people or acquiring information on the internet, use of social media becomes a part of their daily lives. A lot of changes of consumer culture, which have been occurring through social media, have significant effects on corporate marketing activities. Since social media's importance to airlines has been continuously increased, this study attempts to examine effects of passengers' uses of social media, who plan to select an airline, on dependence on reliance of electronic word-of mouth(EWOM) and EWOM acceptance. To this end, a questionnaire survey of passengers who use airlines and the airline's social media was conducted, and then effective data of 302 copies were analyzed by using the structural equation modeling. The findings show that social media use intensity has a significant effect on Acceptance of EWOM via reliance of EWOM, while a direct effect of social media use intensity on Acceptance of EWOM is not significant. From this study, it is found that control and management of social media and only EWOM are effective tools for marketing of airline businesses, suggesting that innovative strategies are required to preemptively cope with changes in consumers' behaviors and markets, which continue to evolve.

Design and Implementation of the Central Queue Based Loop Scheduling Method (중앙 큐 기반의 루프 스케쥴링 기법의 설계 및 구현)

  • Kim, Hyun-Chul;Kim, Hyo-Cheol;Yoo, Kee-Young
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.38 no.5
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    • pp.16-26
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    • 2001
  • In this paper, we present a new scheduling method called CDSS(Carried-Dependence Self-Scheduling) for efficiently execution of the loop with intra dependency between iterations based on the central queue. We also implemented it on shared memory system using Java language. Also, we study the modification that converts the existing self-scheduling method based on the central task queue for parallel loops onto the same form applied to loop with loop-carried dependences. The proposed method is self scheduling and assigns the loops in three-level considering the synchronization point according to the dependence distance of the loops. To adapt the proposed scheme and modified methods into various platforms, including a uni-processor system, we use threads for implementation. Compared to other assignment algorithms with various changes of application and system parameters, CDSS is found to be more efficient than other methods in overall execution time including scheduling overheads. CDSS shows improved performance over modified SS, Factoring, GSS and CSS by about 0.02, 40.5, 46.1 and 53.6%, respectively. In CDSS, we achieve the best performance on varying application programs using a few threads, which equal the dependence distance.

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Theoretical study of the optical properties of low voltage stacked cholesteric liquid-crystal displays

  • Valyukh, Iryna;Valyukh, Sergiy;Skarp, Kent
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.202-204
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    • 2004
  • We study theoretically optical properties of thin layered stacked monochrome cholesteric liquid-crystal displays. Thin thickness of the layers (${\sim}1{\mu}m$) allows us appreciably to reduce driving voltage and use such displays in smart cards. Good selective reflection is achieved due to stacked structure. Dependence of the reflectivity of this type of displays on the quantity of the layers, their thickness, and liquid crystal birefringence is investigated.

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