• Structural Engineering and Mechanics
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• 제12권6호
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• pp.657-668
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• 2001

Fiber reinforced cementitious composites are nowadays widely applied in civil engineering. The postcracking performance of this material depends on the interaction between a steel fiber, which is obliquely across a crack, and its surrounding matrix. While the partly debonded steel fiber is subjected to pulling out from the matrix and simultaneously subjected to transverse force, it may be modelled as a Bernoulli-Euler beam partly supported on an elastic foundation with non-linearly varying modulus. The fiber bridging the crack may be cut into two parts to simplify the problem (Leung and Li 1992). To obtain the transverse displacement at the cut end of the fiber (Fig. 1), it is convenient to directly solve the corresponding differential equation. At the first glance, it is a classical beam on foundation problem. However, the differential equation is not analytically solvable due to the non-linear distribution of the foundation stiffness. Moreover, since the second order deformation effect is included, the boundary conditions become complex and hence conventional numerical tools such as the spline or difference methods may not be sufficient. In this study, moment equilibrium is the basis for formulation of the fundamental differential equation for the beam (Timoshenko 1956). For the cantilever part of the beam, direct integration is performed. For the non-linearly supported part, a transformation is carried out to reduce the higher order differential equation into one order simultaneous equations. The Runge-Kutta technique is employed for the solution within the boundary domain. Finally, multi-dimensional optimization approaches are carefully tested and applied to find the boundary values that are of interest. The numerical solution procedure is demonstrated to be stable and convergent.

• 한국광학회지
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• 제18권3호
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• pp.179-184
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• 2007

본 논문은 가시광선 반사 스펙트럼으로부터 피부조직의 광학적, 구조적 특성을 역 추출하는 알고리즘에 대한 연구를 다룬다. 본 연구에서는 유전알고리즘을 사용한 기존의 역 추적 최적화 알고리즘에 파장 선택법과 심플렉스법을 추가하여 알고리즘의 최적화 능력을 개선하였다. 파장 선택법은 기존 알고리즘에 사용된 135개의 파장 중 10개의 유효 파장만을 사용한 결과 계산시간이 83% 감소하였다. 심플렉스법을 사용해 유전알고리즘으로 얻은 근사적인 탐색 점으로부터 재 탐색을 수행하였고, 이를 통해 얻은 탐색 점의 SSE(sum of square error)는 기존 유전알고리즘 만으로 얻은 탐색 점이 가지는 SSE의 0.64%였다. 본 연구의 모델링 결과를 통해 개선된 알고리즘이 기존 알고리즘에 비해 빠르고 정확한 해를 찾는다는 것을 확인할 수 있었다.

• 한국건축시공학회지
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• 제2권4호
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• pp.89-98
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• 2002

Self-leveling material(SLM) is one of the floor finishing materials which make flat surface like as water level by itself in a short time. So it is possible to increase construction speed and enhance economical efficiency In this study, author intended to develop SLM for the industrial warehouse and factory loading heavy weight machinery and vehicles. The demanded properties for this type of SLM are above 200mm of flow value and above 300kgf/$cm^2$ of 28-days compressive strength. To possess demended strength and fluidity, SLM have to be composed of many types of binders and chemical additives. So it is difficult to decide suitable mixing proportion of composition materials. In this study, author investigated the weight percentage effect of main composition materials for high-strength self-leveling material, by experimental design such as tables of orthogonal arrays and simplex design, and by statistical analysis such as analysis of variance and analysis of response surface. Variables of experiments were ordinary Portland cement(OPC), alumina cement(AC), anhydrous gypsum(AG), lime stone(LS) and sand, and properties of tests were fluidity of fresh state and strength of hardened state. Results of this study are showed that suitable mix proportions of binders for the high strength self-leveling materials are two groups. One is 78~85.5% OPC, 7.5~9.5% AC, 9~12.5% AG and the other is 72.5~78% OPC, 9~12.5% AC, 13~15% AG.

• 한국수정란이식학회지
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• 제29권3호
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• pp.229-234
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• 2014

The aim of the present study was to compare two different serum-free media, modified synthetic oviduct fluid (mSOF) and modified potassium simplex optimization medium (mKSOM) containing 20% RD (RPMI1640 + DMEM, 1:1 v/v) (RD-mKSOM), for in vitro culture (IVC) of bovine embryos. After in vitro maturation and fertilization, the presumptive zygotes were cultured in two different serum-free conditions for 7 days and 9 days to evaluate blastocyst formation and hatching, respectively. Serum supplemented conventional CR2 medium was used as control. After 7 day of culture, there was no significant difference in cleavage and blastocyst formation rates among three groups (mSOF, 59.3 and 30.1%; RD-mKSOM, 65.0 and 41.5%; control, 51.6 and 38.0%, respectively). Hatching rate was significantly higher in control (69.0%) than other experimental groups (mSOF, 22.0%; RD-mKSOM, 39.5%) (P<0.0001 and P<0.001, respectively). Although both serum-free conditions showed lower hatching rates than serum-added control, in serum-free groups, RD-mKSOM showed significantly higher hatching rate than mSOF (P<0.001). In addition, one-step using RD-mKSOM may facilitate IVC procedure than two-step culture system. In conclusion, the results indicate that one-step RD-mKSOM is more suitable defined culture system for IVC of bovine embryos than two-step mSOF.

• 한국미생물·생명공학회지
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• 제48권2호
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• pp.230-235
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• 2020

The global evolution of antibiotic resistance has threatened the efficacy of available treatment options with ravaging impacts observed in developing countries. As a result, investigations into the prevalence of antibiotic resistance and the role of plasmids are crucial. In this study, we investigated the presence and distribution of bla_TEM and gyrA genes, plasmid profiles, and the antimicrobial susceptibility pattern of Salmonella strains isolated from raw meat and stool sources across Niger State, Nigeria. Ninety-eight samples, comprising 72 raw meat and 26 stool samples, were screened for Salmonella spp. The antimicrobial susceptibility of Salmonella isolates to 10 commonly used antimicrobial agents was determined using the KirbyBauer disc diffusion method. Isolates were further analyzed for plasmids, in addition to PCR amplification of beta-lactamase (bla_TEM) and gyrA genes. A total of 31 Salmonella spp. were isolated, with 22 from raw meat (70.97%) and 9 from stool (29.03%). Salmonella spp. with multiple resistance patterns to ceftazidime, cefuroxime, ceftriaxone, erythromycin, ampicillin, cloxacillin, and gentamicin were detected. Ofloxacin and ciprofloxacin were found to be the most effective among the antibiotics tested, with 67.7% and 93.5% susceptible isolates, respectively. Nine (29.03%) isolates harbored plasmids with molecular sizes ranging between 6557 bp and 23137 bp. PCR amplification of gyrA was detected in 1 (3.23%) of the 31 isolates while 28 isolates (90.32%) were positive for bla_TEM. This study shows the incidence of antibiotic resistance in Salmonella isolates and the possible role of plasmids; it also highlights the prevalence of ampicillin resistance in this local population.

• 한국정보전자통신기술학회논문지
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• 제10권6호
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• pp.552-557
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• 2017

유 무선 디지털 방송이 고화질 TV의 탄생과 함께 2010년 이후로 급격하게 확산되었으며, 단방향 콘텐츠 이용뿐만 아니라 양방향 콘텐츠 이용이 급격하게 증가되고 있다. 현재 우리나라 위성 통신망에서는 유럽 디지털 방송 표준화기구의 DVB를 국내 데이터 방송의 표준으로 채택하고 있으며, IPTV의 발전에 의해 선택적 콘텐츠의 이용방법도 또한 다양하게 연구되었다. 디지털 방송에서는 MPEG-2 system의 비디오, 오디오, 그리고 데이터 등의 멀티미디어 정보를 전송하기 위해 정보를 다중화 하는 방식으로 Transport Stream Packet(TSP)을 이용한 방식을 사용하는데, 이 Stream에는 비디오, 오디오 정보는 물론, TV 편성표와 프로그램에 대한 상세한 정보까지도 포함되어 있다. 본 연구에서는 이러한 데이터 방송 시스템을 이해하기 위하여 Linux 환경에서 Transport Stream(TS)을 Packet별로 구분하고 각각의 기능별로 분석, 출력해주는 TS Analyzer를 구현하였으며, TS의 이해를 돕고 Stream Parsing 능력향상을 이룰 수 있었다.

• Journal of Species Research
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• 제2권1호
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• pp.15-54
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• 2013

Surveys on Jeju-do (Quelpart Isl.) unearthed about 40 earthworm species or sub-species. Several considered new to science are described. Only a dozen were previously known and these are taxonomically reviewed. The two most commonly recorded in surveys by S. Kobayashi in the 1930s were Drawida anchingiana Chen, 1933 and Metaphire quelparta (Kobayashi, 1937), neither recently relocated. Morphologically similar taxa, supported with DNA barcodes, for Moniligastridae, are Drawida anchingiana seogwipo, D. anchingiana halla and D. iucn spp. or sub-spp. nov. For Megascolecidae, new taxa and synonyms are: Amynthas arx and A. aucklandis spp. nov. that have seminal grooves rather than the eversible male pores of Metaphire plus Amynthas simplex is another new species. Amynthas sangumburi Hong & Kim, 2002 is recognized as a probable new synonym within the A. corticis (Kinberg, 1867) species-group while Amynthas corticis saeseum sub-sp nov. is described. Amynthas gracilis (Kinberg, 1867) is a new record from Jeju and Korea (with A. bouchei, A. omodeoi and A. edwardsi all by Zhao & Qiu, 2009 possible synonyms of this species group from China) with a Jejuan sub-species, A. gracilis insularum, sub-sp. nov. Presence on Jeju of Amynthas carnosus (Goto & Hatai, 1899) is confirmed (its further new synonyms are Chinese A. fuscus Qiu & Sun, 2012 and A. taiwumontis Shen et al., 2013), as is A. micronarius (Goto & Hatai, 1898) (with new synonym A. montanus Qiu & Sun, 2012 also an invalid secondary homonym). Amynthas phaselus maculosus (Hatai, 1930) is in new combination with A. kamitai (Kobayashi, 1934) and A. minjae Hong, 2001 syns. nov. Two newly described Metaphire quelparta sub-spp are M. q. seogwipo and M. q. valhalla these being supported with DNA barcodes despite the nominal taxon not yet being confirmed.

• 한국동물위생학회지
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• 제27권4호
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• pp.355-369
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• 2004

The equine herpesvirus type 1 (EHV-1) immediate-early (IE) protein is a potent transactivator responsible for the activation of both early and late genes during the course of infection and is comprised of discrete functional domains that mediate its many functions. Interaction between trans activators such as the IE protein and various components of the RNA polymerase II transcription initiation machinery has been demonstrated to be critical for transactivation. In the present report, it is addressed the hypothesis that the IE protein interacts with various components of transcription machinery to mediate transactivation of target viral genes. In these studies, it is demonstrated that in vitro transcribed and translated IE protein interacts with TFIIB-agarose conjugate but not with TFIID-agarose conjugate. Additional immunoprecipitation studies using nuclear extracts derived from EHV-1 infected RK-13 cells confirmed that the IE protein interacts strongly with TFIIB, but fails to interact with TFIID. IR2, a truncated form of the IE protein lacking the potent transactivation domain and involved in the down-regulation of the IE gene, also interacted with TFIIB but not with TFIID. Studies were also performed to ascertain if particular TBP-associated factors (TAFs) could mediate IE or IR2 binding to TFIID. In vitro transcribed and translated TAF250 added to nuclear extracts generated from EHV-1 infected cells also failed to mediate an interaction between the IE protein or the IR2 protein and TFIID. This study demonstrated that the IE protein mediates transactivation of target viral genes by a mechanism that involves TFIIB. This is in contrast to mechanisms that have been proposed for both the herpes simplex virus ICP4 and VP16 protein which have been proposed to transactivate viral genes through interactions involving both TFIIB and TFIID. This study also intimates that IR2 mediate its repressive effects during the course of EHV-1 infection by a mechanism that involves sequestration of various transcription factors.

• 한국해양바이오학회지
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• 제5권4호
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• pp.33-39
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• 2011

As a rapid and quick bioactive compound evaluation technique, we utilized an automatic system of high throughput screening (HTS) to investigate ${\alpha}$-glucosidase inhibitory efficacy of seaweeds, collected from Jeju Island in Korea. In this study, different extracts with methanol at $20^{\circ}C$ and $70^{\circ}C$ from 23 species of brown seaweeds and 22 species of red seaweeds and 9 species of green seaweeds were subjected to HTS. Of the brown seaweeds tested, Myelophycus simplex (20B3), Ishige sinicola (20B5, 70B5), Colpomenia sinuosa, (20B14, 70B14), Hizikia fusiforme (20B21), Ishige okamurai (70B22) and Ecklonia cava (70B23) showed significantly high ${\alpha}$-glucosidase inhibitory activity with 96.52%, 98.34%, 98.37%, 80.49%, 96.16%, 76.32%, 98.32% and 98.12%. Schizymenia dubyi (20R15), Gelidium amansii (20R16) and Polysiphonia japonica (70R22) amomng the red seaweeds showed remarkable ${\alpha}$-glucosidase inhibitory activity more than 95%. On the other hand, the green seaweeds showed poor ${\alpha}$-glucosidase inhibitory activities (less the10%) at 1 mg/ml.

• Molecules and Cells
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• 제21권1호
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• pp.104-111
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• 2006

Gene therapy with nonviral vectors using the suicide gene/prodrug activating system of herpes simplex virus type-1 thymidine kinase (HSV1-TK)/ganciclovir (GCV) is inefficient in killing malignant tumor cells due to two major factors: (a) an unsatisfactory bystander effect; (b) short-lived expression of the protein. To study the capacity of the protein transduction domain (PTD) of HIV-1 TAT protein to enhance HSV1-TK/GCV cancer gene therapy, we constructed three fusion proteins TAT-TK, TK-TAT and TK. TAT-TK retained as much enzyme activity as TK, whereas that of TK-TAT was much lower. TAT-TK can enter HepG2 cells and much of it is translocated to the nucleus. The transduced HepG2 cells are killed by exogenously added GCV and have bystander effects on untransduced HepG2 cells. Most importantly, the introduced recombinant protein is stable and remains functional for several days at least, probably because nuclear localization protects it from the cytoplasmic degradation machinery and provides access to the nuclear transcription machinery. Our results indicate that TAT fusion proteins traffic intercellularly and have enhanced stability and prodrug cell killing activity. We conclude that TAT has potential for enhancing enzyme prodrug treatment of liver cancers.