• The Korean Journal of Zoology
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• v.39 no.3
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• pp.273-281
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• 1996

Previously, we have proposed a two-cell type model for follicular steroidogenesis inamphibians with Rana nigromacu lota. Present experiments were carried out to ascertain whether the model Is applicable to R. dybowskii. The role of theca layer were also reassessed by using granulosa cell-free pure theca layer (P-THEP). Theca/epithelium (THEP) layers, P-THEP layers, and granulosa cell enclosed-oocytes () were obtained from ovarian follicles of R. dybowskii by microdissection. Intact follicles (IFs) and different types of tissues were cultured for 6 hour in amphibian Ringer's m the presence or absence of FPII (0.05 gland/mi) or various steroid precursor (100 ng/ml). The amounts of product steroids converted by the components were measured by RIA. Exogenously added pregnenolone (P5) resulted in a marked increase in progesterone (P$_4$) by GCEOs (2143 pg/follicle) and IFs (2346 pg/follicle) but a smaller increase in P4 by THEP layer (495 pg/follicle). Addition of P$_4$ increased 17 a-hydroxyprogesterone (17 $\alpha$-OHP$_4$) levels by GCEOs (1118 pg/follicle) and IFs (1333 pg/follicle) but less by THEP layer (290 pg/follicle). However, much less amounts of P$_4$ or 17 $\alpha$-OHP$_4$ were producad by P-THEP layers than THEP in the presence of P5. Exogenous 1 7$\alpha$-OIIP$_4$ increased androstenedione (AD) levels by GCEOs (1415 pg/follicle) and IFs (561 pg/follicle) but not by THEP layers. In contrast, addition of AD resulted m a marked increase in testosterone (T) levels by TIIEP (2594 pg/follicle) and IFs (2223 pg/follide) but much less by GCEOs (339 pg/follicle). Exogenous T increased estradiol (E$_2$) levels by GCEOs (551pg/follicle) and IFs (887 pg/follicle), but not by THEP layer (<10 pg/follicle). Without addition of FPH or steroid precursors, very low or nondetectable levels of steroids were produced (< 20 pg/follicle) by all the types of follicular components examined. The data presented here indicate that the two-cell type model based on the study with R. nigromacu Iota is applicable to R. dybowskii and also suggest that the minor pathway, which convert P5 to 17$\alpha$-OHP$_4$, is not present in theca layer.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.361-371
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• 2005

The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

• Journal of Science Education
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• v.41 no.3
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• pp.426-446
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• 2017

The purpose of this study was to analyze undergraduate students' reasoning for solving a problem about a rock and investigate the roles and importance of critical evidence (CE) and critical resource models (CRMs) in abductive reasoning. Participants were 20 senior undergraduate students enrolled in a science major course in a university of education. They were asked to abductively infer geologic processes of sedimentary rocks having a lot of holes and represent them with models. Their reasoning were analyzed according to a scheme for modeling-based abductive reasoning. As a result, successful student reasoning was characterized by using a diversity of grains and lots of holes as CE, activating the sedimentary rock formation and weathering as CRMs, and combining the CRMs into a scientifically sound explanatory model (SSEM). By contrast, in the reasoning unsuccessful in proposing a SSEM, students activated the igneous rock (basalt) formation and deposition as resource models (RMs) based on the evidence of the holes in the rocks and diverse grains, respectively, and used the RMs to construct their own explanatory models (EMs). It was suggested that to construct SSEMs to solve earth scientific problems about rocks, students need to know what could be CE in a particular problem situation, take an integrative or systemic approach to a rock problem, use multiple RMs, and evaluate RMs or EMs in light of evidence.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1323-1329
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• 2005

A mathematical model was developed for predicting the growth kinetics of Listeria monocytogenes in tryptic soy broth (TSB) as a function of combined effects of temperature, pH, and NaCl. The TSB containing four different concentrations of NaCl (2, 4, 5, and $10\%$) was initially adjusted to six different pH levels (pH 5, 6, 7, 8, 9, and 10) and incubated at 4, 10, 25, or 37$^{circ}C$. In all experimental variables, the primary growth curves were well fitted ($r^{2}$=0.982 to 0.998) to a Gompertz equation to obtain the lag time (LT) and specific growth rate (SGR). Surface response models were identified as appropriate secondary models for LT and SGR on the basis of coefficient determination ($r^{2}$=0.907 for LT, 0.964 for SGR), mean square error (MSE=3.389 for LT, 0.018 for SGR), bias factor ($B_{1}$B,=0.706 for LT, 0.836 for SGR), and accuracy factor ($A_{f}$=1.567 for LT, 1.213 for SGR). Therefore, the developed secondary model proved reliable predictions of the combined effect of temperature, NaCl, and pH on both LT and SGR for L. monocytogenes in TSB.

• Journal of Global Scholars of Marketing Science
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• v.13
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• pp.113-133
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• 2004

The present study examines the the role of subjectively perceived factors of the attitude toward job-seeking activities in forming an intention to use a web. An integrative research model is presented and tested empirically. It includes the following two aspects of belief in Davis' TAM: perceived usefulness, perceived ease of use. Specially, internet job-seeking efficacy, or the belief in one's capabilities to organize and execute courses of Internet actions required to achieve given goals, is a potentially important factor in efforts to gain more favorable attitude toward Internet uses. Survey data were collected to develop a reliable operational measure of Internet job-seeking efficacy and to examine its construct validity. An four-item Internet job-seeking efficacy scale developed for the present study was found to be reliable and internally consistent. Also, many previous studies have established that perceived usefulness is an important factor influencing user acceptance and usage behavior of information technologies. However, very little research has been conducted to understand how that perception forms and changes over time. The current work presents and tests the determinants of perceived usefulness. The present study found that higher internet job-seeking efficacy is an important concept which is significantly related to job-seeking activities by positively influencing intention and performance as well as usefulness on the Internet.

• The Journal of Society for e-Business Studies
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• v.14 no.2
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• pp.71-94
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• 2009

The purpose of this study is to identify the effects of interactivity, computer playfulness, and computer anxiety on service satisfaction, attitude, and user intention based on the flow theory in order to understand factors improving effects of home-network system. Especially, Computer anxiety which is one of individual characteristics in negative aspect as well as computer playfulness was added to the research model to perform empirical research for grasping effects on attitude variables such as service satisfaction. The analysis resulted that the perceived interactivity and the computer playfulness had a positive relationship with service satisfaction, but on the contrary it was identified that the computer anxiety gave a negative effect on the service satisfaction. These results are evidences to explain high correlation of the perceived interactivity, the computer playfulness, and the computer anxiety with the service satisfaction. Besides, it was found that there was a meaningful relationship among the three attitude variables such as satisfaction, attitude, and intention to use. This research suggested an integrative research model using home-network technology where user satisfaction and use factors were included, expanded research area of the traditional interactivity, and presented a consistent result to support the relationship among the service satisfaction, the attitude, and the intention to use. In additions, practical issues were also provided by presenting user's criteria for selecting various services including electronic commerce and its using elements continuously.

• Korean Journal of Social Welfare
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• v.52
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• pp.89-115
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• 2003

While many social work studies has focused on the development of practice intervention and demonstration of the efficacy, little attention has been given to the way how the results can be disseminated and utilized in practice area. But attempts to bridge the research-practice gap empathize importance of dissemination and utilization including knowledge utilization, innovation diffusion, information dissemination, program replication, and technology transfer etc. In this recognition, this study that focused on the process after development of program tried to search and analyze the real disseminating process and utilization state with applying Growing-up Skills Program(GUSP) developed and disseminated by this researcher. For the purpose, theories and models for program diffusion were reviewed, and dissemination & utilization of GUSP was analyzed on the 'Herie & Martin's model' with retrospective perspectives. Through this tracer study, these were confirmed or founded as problems of GUSP in disseminating process : lack of specific strategy for the dissemination ; unplanned coping due to little preparation ; and unclear and insufficient understanding of the target system in the beginning stage of dissemination. And followings are suggested for the improvement of social work program dissemination & utilization in the field: to conduct diffusion process on the basis of a proper model; to consider integrative relationship between D&D and dissemination & utilization ; to endeavor for collecting feed back from the field ; and to reinforce social work education and study related to innovation diffusion. These results showed importance of dissemination & utilization in social work and utility of GUSP despite of several limitations. More concerns of dissemination & utilization are needed for the integration of research and practice in Korean social work.

• Korean Journal of Social Welfare Studies
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• v.43 no.1
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• pp.339-363
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• 2012

This study examines the effects of adolescents' volunteer activities on their development of sense of community. When examining the effects of volunteer activities, both quantity and quality sides of volunteer activities were considered in the research model and besides the direct effects of volunteer activities on their sense of community, the mediating role of self-esteem and peer attachment were also examined. The data set of conducted by National Youth Policy Institute was reanalyzed for this study. The subjects of this study were 1,426 first-grade middle school students who had experiences of volunteer activities. The results of the study are as follows. First, the total hours of volunteer activities and the satisfaction with volunteer activities were positively related to their sense of community respectively. In an integrative model which combines both quantity and quality aspects of volunteer activities, however, only the satisfaction with volunteer activities was found to be significant. This means that the satisfaction with and reflective learning after volunteer activities are more important sides of adolescents' volunteer activities than whether and how many times they had experiences in volunteer activities. Second, the satisfaction with volunteer activities was found to enhance adolescents' self-esteem and peer attachment and the changes in their personal traits again led to a higher sense of community. Therefore, both the direct effects of volunteer activities and indirect effects through self-esteem and peer attachment were proved. Based on the results of the study, the need and ways to improve the management system of adolescents' volunteer activities were suggested.

• The Journal of Internal Korean Medicine
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• v.45 no.1
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• pp.11-30
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• 2024

Objectives: This study evaluated the effects of Ssanghwa-tang (SHT) on lung injury and muscle loss in a COPD mouse model. Methods: C57BL/6 mice were challenged with cigarette smoke extract and lipopolysaccharide, and then treated with two concentrations of SHT (250 and 500 mg/kg). After sacrifice, the bronchoalveolar lavage fluid (BALF) or lung tissue was analyzed by cytospin, ELISA, real-time PCR, flow cytometry analysis, and H&E and Masson's trichrome staining. The grip strength of COPD mice was measured using a grip strength meter. The running time of COPD mice was measured by a treadmill test. Muscle tissue of the quadriceps was stained with H&E and Masson's trichrome staining. Results: SHT significantly inhibited the increase in neutrophil numbers in BALF and significantly decreased immune cell activity in BALF and lung tissue. It also significantly inhibited the increase in TNF-α, IL-17, and MIP2 in BALF. Real-time PCR analysis revealed that the mRNA expression of TNF-α, IL-17, MIP2, and TRPV1 in lung tissue showed a significant decrease compared with the control group. Lung tissue damage was significantly reduced in the histological analysis. The grip strength and running time of the COPD mice showed a significant decrease compared with the control group. In histological staining, SHT was found to reduce the damage to muscle tissue. Conclusions: This study indicates that SHT can be used as a therapeutic agent for COPD patients by inhibiting lung injury and muscle loss.

• Asia pacific journal of information systems
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• v.23 no.4
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• pp.103-128
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• 2013

When a consumer needs a product or service and multiple sellers are available online, the process of selecting a seller to buy online from is complex since the process involves many behavioral dimensions that have to be taken into account. As a part of this selection process, consumers may set minimum trust expectation that can be used to screen out less trustworthy sellers. In the previous research, the level of consumers' trust expectation has been anchored on two important factors: product involvement and perceived risk. Product involvement refers to the extent to which a consumer perceives a specific product important. Thus, the higher product involvement may result in the higher trust expectation in sellers. On the other hand, other related studies found that when consumers perceived a higher level of risk (e.g., credit card fraud risk), they set higher trust expectation as well. While abundant research exists addressing the relationship between product involvement and perceived risk, little attention has been paid to the integrative view of the link between the two constructs and their impacts on the trust expectation. The present paper is a step toward filling this research gap. The purpose of this paper is to understand the process by which a consumer chooses an online merchant by examining the relationships among product involvement, perceived risk, trust expectation, and intention to buy from an e-tailer. We specifically focus on the mediating role of perceived risk in the relationships between enduring product involvement and the trust expectation. That is, we question whether product involvement affects the trust expectation directly without mediation or indirectly mediated by perceived risk. The research model with four hypotheses was initially tested using data gathered from 635 respondents through an online survey method. The structural equation modeling technique with partial least square was used to validate the instrument and the proposed model. The results showed that three out of the four hypotheses formulated were supported. First, we found that the intention to buy from a digital storefront is positively and significantly influenced by the trust expectation, providing support for H4 (trust expectation ${\rightarrow}$ purchase intention). Second, perceived risk was found to be a strong predictor of trust expectation, supporting H2 as well (perceived risk ${\rightarrow}$ trust expectation). Third, we did not find any evidence of direct influence of product involvement, which caused H3 to be rejected (product involvement ${\rightarrow}$ trust expectation). Finally, we found significant positive relationship between product involvement and perceived risk (H1: product involvement ${\rightarrow}$ perceived risk), which suggests that the possibility of complete mediation of perceived risk in the relationship between enduring product involvement and the trust expectation. As a result, we conducted an additional test for the mediation effect by comparing the original model with the revised model without the mediator variable of perceived risk. Indeed, we found that there exists a strong influence of product involvement on the trust expectation (by intentionally eliminating the variable of perceived risk) that was suppressed (i.e., mediated) by the perceived risk in the original model. The Sobel test statistically confirmed the complete mediation effect. Results of this study offer the following key findings. First, enduring product involvement is positively related to perceived risk, implying that the higher a consumer is enduringly involved with a given product, the greater risk he or she is likely to perceive with regards to the online purchase of the product. Second, perceived risk is positively related to trust expectation. A consumer with great risk perceptions concerning the online purchase is likely to buy from a highly trustworthy online merchant, thereby mitigating potential risks. Finally, product involvement was found to have no direct influence on trust expectation, but the relationship between the two constructs was indirect and mediated by the perceived risk. This is perhaps an important theoretical integration of two separate streams of literature on product involvement and perceived risk. The present research also provides useful implications for practitioners as well as academicians. First, one implication for practicing managers in online retail stores is that they should invest in reducing the perceived risk of consumers in order to lower down the trust expectation and thus increasing the consumer's intention to purchase products or services. Second, an academic implication is that perceived risk mediates the relationship between enduring product involvement and trust expectation. Further research is needed to elaborate the theoretical relationships among the constructs under consideration.