• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.371-379
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• 2013

This paper investigates the cracking and tension-stiffening behavior of 100 MPa shrinkage-compensated strain-hardening cement composite (SHCC) and conventional concrete tie elements in monotonic and cyclic tension. Strain and surface crack formation of tension ties were monitored with two strain displacement transducers and a photo microscope with a lens of magnification 50 times. Three different cement composites such as conventional concrete, shrinkage-compensated SHCC, and normal SHCC were used in the tie specimens to investigate the influence of the cement composite type on the tension stiffening and cracking behavior. Test results indicated that initial shrinkage of the ultra high-strength cement composites is greatly reduced as the 10% replacement of cement by the shrinkage-compensating admixture based on calcium sulfo-aluminate (CSA). The test results on the SHCC tension ties showed that the first cracking load decreases proportionally to the initial shrinkage strain. Reinforced ultra high-strength SHCC ties with the initial shrinkage compensation exhibited improved tension stiffening and smaller crack spacings, i.e. the reduction in crack width. Cyclic loading did not have a significant effect on tension stiffening and cracking behavior of tension ties with normal concrete and SHCC materials.

• 대한공업교육학회지
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• v.39 no.2
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• pp.19-36
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• 2014

The purposes of this study are to grasp industry vocational subject student-teachers' instruction area, compare cognitive level of cooperating teacher and student-teachers for the importance of instruction area and secure base data required to develop educational practical area of professional teachers in specialized high school. To achieve this, instruction area of instruction teacher in charge of industry vocational subject pre-teacher education was developed by document consideration and expert verification and differences of importance cognition for the area was compared between educational practice insturction teacher and student-teacher. The results are as the following. First, for the instruction areas that educational practice instruction teachers should teach student-teacher, there are 7 categories, 17 mid-fields and 85 subsections. Especially expert group suggested an opinion that areas of teacher's values and personality formation should be added to pre-teachers. And, they judged that category of school business showed low validity for educational practice instruction teacher's instruction area. Second, educational practice instruction teacher importantly cognized 'class activity', 'student instruction and class management' and 'development of desirable view of education attitude'. On the other hand, they cognized 'development and management of curriculum', 'support on educational activity', 'industrial-educational cooperation and tie with local community' and 'specialty improvement' less importantly. Student-teachers cognized 'class activity', 'student instruction and class management', 'specialty improvement', 'development of desirable view of education attitude' importantly. They cognized 'development and management of curriculum', 'support on educational activity' and 'industrial-educational cooperation and tie with local community' relatively less importantly. Third, both educational practice instruction teachers and student-teachers importantly cognized 'class activity', 'student instruction and class management' and 'development of desirable view of education attitude'. However, student-teachers importantly cognized, but educational practice instruction teachers didn't importantly cognized 'specialty improvement'. Both two group cognized 'development and management of curriculum', 'support on educational activity' and 'industrial-educational cooperation and tie with local community' less importantly.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.97-109
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• 2014

Social media is a general term for online services by which users share opinions, perspectives, and experiences. It supports interactions between users in sharing contents on it and weak ties among them play an important role in the process. This exploratory study attempts to identify crucial factors of establishing weak ties between social media users in the perspective of social network theory and uncertainty reduction theory. We collected data through diary study and in-depth interview and analyzed it following grounded theory approach. As a result, social media users more actively interacted each other or shared contents based on weak ties, compared to strong ties. In addition, similarity, self-disclosure, and relevance appeared to facilitate establishment of weak ties, by reducing psychological distance between social media users and perceived uncertainty of them.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1321-1329
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• 2009

Web technology has allowed the rise of services such as blogs or YouTube that make possible the sharing of opinions, perspectives, and experiences with other users through contents. Online services that promote such sharing of information and communication are known as social media. Recently, the explosive growth of these services displays the carry-over of the natural sociality that all humans possess as social creatures. This study took an exploratory approach in investigating what influential relationships are involved in forming new relationships through sharing and participation, as sharing and participation are core keywords of social media. In order to do this, relationship formations were observed in actual usage environments with the use of the diary study method and in-depth interviews. This study sought to deduce necessary elements in relationship formations and examine the influences of weak ties on participation and sharing.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3061-3065
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• 2015

Background: Rac3, a member of the Rac family of small guanosine triphosphatases (GTPases), regulates a variety of cell functions, including the organization of the cytoskeleton, cell migration, and invasion. Overexpression of Rac3 has been reported in several human cancers. However, the role of Rac3 in lung cancer (LC) has not been determined in detail. The purpose of this study was to investigate the effect of silencing of Rac3 expression in human LC cells and the consequences for cell survival. Materials and Methods: Lentivirus small hairpin RNA (shRNA) interference techniques were utilized to knock down the Rac3 gene. Gene and protein expression was quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. LC cell apoptosis was examined by annexin V-APC /propidium iodide staining. Results: Efficient silencing of Rac3 strongly inhibited A549 cell proliferation and colony formation ability, and significantly decreased tumor growth. Moreover, flow cytometry analysis showed that knockdown of Rac3 led to G2/M phase cell cycle arrest as well as an excess accumulation of cells in the G1 and S phase. Conclusions: Thus, functional analysis using shRNAs revealed a critical role for Rac3 in the tumor growth of LC cells. shRNA silencing of Rac3 could provide an effective strategy to treat LC.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.80.1-80.1
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• 2017

We present preliminary results of KVN single dish telescope observations of 80 dense cores in the Orion molecular cloud complex which contains the Orion A, B, and ${\lambda}$ Orionis cloud. We investigate the behavior of the different molecular tracers and look for chemical variations of cores in the three clouds in order to systematically investigate the effects of stellar feedback. The most commonly detected molecular lines (with the detection rates higher than 50%) are N2H+, HCO+, H13CO+, C2H, HCN, and H2CO. The detection rates of dense gas tracers, N2H+, HCO+, H13CO+, and C2H show the lowest values in the ${\lambda}$ Orionis cloud. We find difference between molecular D/H ratios and N2H+/H13CO+ abundance ratios towards different clouds, and between protostellar cores and starless cores. Eight starless cores in the Orion A and B clouds exhibit high deuterium fractionations, larger than 0.10, while in the ${\lambda}$ Orionis cloud, no cores reveal the high ratio. These chemical properties could support that cores in the ${\lambda}$ Orionis cloud are affected by the photo-dissociation and external heating from the nearby H II region, which is a hint of negative stellar feedback on core formation. The striking difference between the [N2H+]/[H13CO+] ratios leads us to suggest that there are significant evolutionary differences between the Orion A/B and ${\lambda}$ Orionis clouds. In order to examine whether starless cores can be candidates of pre-stellar cores, we compared the core masses estimated from the 850 um emission to their Virial masses calculated from the N2H+ line data and find that most of them are not gravitationally bound in the three clouds.

• KSBB Journal
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• v.17 no.6
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• pp.566-570
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• 2002

In lactic acid fermentation, the end product inhibition by lactic acid causes several problems. The most important of which are low lactate formation rate and its recovery from fermentation broth. To overcome these problems, extractive lactic acid fermentation was carried out in a bioreactor, which was connected to a column packed with anion exchange resin (Amberlite IRA-400, 250 g). The system was started as a batch process, and then the separation process was started when the lactic acid concentration reached 10 g/L, 20 g/L or 30 g/L. In each case, total lactic acid concentration was reached to 48.6, 53.6, 52.6 g/L with its productivity of 1.2 g/L $.$ h, 1.6 g/L $.$ h, and 1.3 g/L $.$ h, respectively Especially, in the case of the 20 g/L recycling-initiation process, extractive fermentation reduced tie fermentation time (17 hrs) by 34% in comparison with the conventional batch process. The direct consequence of this time reduction was shown by a 1.8 fold increase in overall lactic acid productivity.

• Molecules and Cells
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• v.37 no.6
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• pp.487-496
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• 2014

Angiotensinogen (AGT), the precursor of angiotensin I, is known to be involved in tumor angiogenesis and associated with the pathogenesis of coronary atherosclerosis. This study was undertaken to determine the role played by AGT in endothelial progenitor cells (EPCs) in tumor progression and metastasis. It was found that the number of EPC colonies formed by AGT heterozygous knockout ($AGT^{+/-}$) cells was less than that formed by wild-type (WT) cells, and that the migration and tube formation abilities of $AGT^{+/-}$ EPCs were significantly lower than those of WT EPCs. In addition, the gene expressions of vascular endothelial growth factor (VEGF), Flk1, angiopoietin (Ang)-1, Ang-2, Tie-2, stromal derived factor (SDF)-1, C-X-C chemokine receptor type 4 (CXCR4), and of endothelial nitric oxide synthase (eNOS) were suppressed in $AGT^{+/-}$ EPCs. Furthermore, the expressions of hypoxia-inducible factor (HIF)-$1{\alpha}$and $-2{\alpha}$ were downregulated in $AGT^{+/-}$ early EPCs under hypoxic conditions, suggesting a blunting of response to hypoxia. Moreover, the activation of Akt/eNOS signaling pathways induced by VEGF, epithelial growth factor (EGF), or SDF-$1{\alpha}$ were suppressed in $AGT^{+/-}$ EPCs. In $AGT^{+/-}$ mice, the incorporation of EPCs into the tumor vasculature was significantly reduced, and lung tumor growth and melanoma metastasis were attenuated. In conclusion, AGT is required for hypoxia-induced vasculogenesis.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.73.1-73.1
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• 2016

We present preliminary results of the submillimeter continuum observations of 14 Planck Galactic Cold Clumps (PGCCs), located in the ${\lambda}$ Orionis Complex. This region is the nearest large HII region, which is an ideal site for a study of the stellar feedback to its surroundings. We observed 14 PGCCs with JCMT/SCUBA-2 and used J=1-0 transitions of CO isotopologues from the PMO mapping observation. Several sub-clumps toward three PGCCs were detected at $850{\mu}m$. In order to examine whether these clumps can be candidates for pre-stellar cores, we compared each clump mass calculated from the $850{\mu}m$ continuum map to its Virial mass and Jeans mass calculated from the $^{12}CO$ and $C^{18}O$ (1-0) spectra, respectively. All clumps have masses smaller than their Virial and Jeans masses, indicating that none of them are gravitational bound and thus in the pre-stellar core stage. Also, the CO depletion factor, which has been derived from the dust continuum and the $C^{18}O$(1-0) line and can be an indicator of core evolution, toward the clumps is in the range of 1 to 5, suggesting that they are not very evolved dense pre-stellar cores. In addition, within individual PGCCs, we found clear gradients of velocity (${\sim}1km\;s^{-1}\;pc^{-1}$) and temperature (${\sim}10K\;pc^{-1}$) in the $^{13}CO$ (1-0) first moment map and the $^{12}CO$(1-0) excitation temperature map, respectively. This can be attributed to the compression and external heating by the HII region, which may prevent clumps from forming gravitationally bound structures and eventually disperse clumps. These results could be a hint about the negative effect of stellar feedback on core formation.

• Journal of the Korean Society of Costume
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• v.61 no.8
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• pp.114-126
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• 2011

Many varieties in folk costumes have inspired fashion designs for a long time. Each country, with a unique style of its own reflects their own traditions, beliefs, customs and morals into their traditional costumes. The traditional methods of creating different ways of drapery methods by using only a rectangular piece of cloth have been passed down from generation to generation and it is still used today. This way of styling has been developed mainly in the Middle East, Asia and Africa and the modifiable ways of creating drapery wearing methods are as follows. The first modifiable styling method is changing the purpose of wearing costumes according to the needs and the wants of the person who wears it. The second method is exposing the knots on the surface of the garments and by doing this, there was no visible difference on the aesthetic formation and it did not alternate for a long time. This means that simple knot shapes have been used to tie edges of rectangular fabrics. The third method is a wrapping type of modifiable styling method, which has been used most commonly in folk costumes because there are lots of ways to wrap a rectangular cloth around the body. The fourth way is the fixed type of modifiable styling method and this method can only be noticed only in the Moroccan Izar using fibulas and belts to alter the shape of the Izar. The fifth method is the composite type of modifiable styling method. This method starts by cutting out cylindrical shapes of fabrics and then wraps or twists it to fit the body. The most significant character of modifiable styling methods in folk costumes is to use rectangular cloths, which varies only in ratio of length, width and sizes. Therefore, this study suggests that rectangular cloths can create enormous amounts of fashion styling which can be easily adapted and created in everyday fashion life.