• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3987-3989
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• 2013

This is a commentary on what a cancer cell is and why cancer cells metastasize. Normal cell get transformed to a cancer cell, with excessive production of free radicals that mutate the DNA of a normal cell. The immortality and malignant stage of transformed cell is maintained by higher GSH levels. With the faster rate of proliferation, when the cancer cell finds the place of origin is not conducive to its further growth, cancer cell chooses to take the metastatic course. We argue that if we can stop the exit of cancer cell from place of origin, cancer spread can be stopped or even cured.

• Geomechanics and Engineering
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• 제5권2호
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• pp.119-142
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• 2013

Pile load tests using Osterberg cells (O-cell) were conducted on cast-in-place concrete piles founded in oil sand fill and in situ oil sand at an industrial plant site in Fort McMurray, Alberta, Canada. Interpreted pile test results show that very high pile shaft resistance (with the Bjerrum-Burland or Beta coefficient of 2.5-4.5) against oil sand could be mobilized at small relative displacements of 2-3% of shaft diameter. Finite element simulations based on linear elastic and elasto-plastic models for oil sand materials were used to analyze the pile load test measurements. Two constitutive models yield comparable top-down load versus pile head displacement curves, but very different behaviour in mobilization of pile shaft and end bearing resistances. The elasto-plastic model produces more consistent matching in both pile shaft and end bearing resistances whereas the linear elastic under- and over-predicts the shaft and end bearing resistances, respectively. The mobilization of high shaft resistance in oil sand under pile load is attributed to the very dense and interlocked structure of oil sand which results in high matrix stiffness, high friction angle, and high shear dilation.

• IMMUNE NETWORK
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• 제23권5호
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• pp.41.1-41.21
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• 2023

CD4 and CD8 T cells are key players in the immune response against both pathogenic infections and cancer. CD4 T cells provide help to CD8 T cells via multiple mechanisms, including licensing dendritic cells (DCs), co-stimulation, and cytokine production. During acute infection and vaccination, CD4 T cell help is important for the development of CD8 T cell memory. However, during chronic viral infection and cancer, CD4 helper T cells are critical for the sustained effector CD8 T cell response, through a variety of mechanisms. In this review, we focus on T cell responses in conditions of chronic Ag stimulation, such as chronic viral infection and cancer. In particular, we address the significant role of CD4 T cell help in promoting effector CD8 T cell responses, emerging techniques that can be utilized to further our understanding of how these interactions may take place in the context of tertiary lymphoid structures, and how this key information can be harnessed for therapeutic utility against cancer.

• 한국미생물·생명공학회지
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• 제5권3호
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• pp.133-140
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• 1977

Nocardia sp의 세포내 징세포구조 및 tellurite 환원초소의 존재부위와 T. T. C. 환원부위를 전자현미경으로 관찰한 것을 요약하면 다음과 같다. 광포내 미세구조에 있어서 unit membrane을 가진 농양구조가 복잡한 형태를 하고 계포질에 내포되어있고 어떤 것은 막구조가 둥글게 감겨있는 형태도 있다. 금속, tellurate염외 석출이 세포질중에 나타나므로 tellurite 및 tellurate 환원효소는 세축질중에 존재한다는 것을 알 수 있다. 그리고T.T.C.의 환원은 세포막 및 세포내막양구조 부분에서 일어난다. 따라서 tellurate환원과 T.T.C.환원은 서로 상이한 부위에서 일어남을 알 수 있다. 구체내에 형성된 T.T.C. tellurate은 도정제인 osmic acid에 의하여 제기화되며, 더우기 탈수제로 사용하고 있는 ethanol에 녹고 아울러 포매각에도 녹기 때문에 약 95％의 formazane이 균체외로 용출되어 나오므로 검정시의 세포내에는 거의 formazane이 존재하지 않기 때문에 전자현미경상의 전자투과성인 부분은 원래 formazane이 형성되었던 부분인 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.876-879
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• 2002

The paper presents the analysis and results of traffic measurements in the 155 Mbit/s real working ATM backbone network. The traffic is described as an ordered sequence of real-time cells. In this paper we analyze two timescales in which some form of a stochastic process is taking place: cell scale and burst scale. We present another way to describe the cell flow in ATM networks by definition the function, designed to be the probability of the burst of length ∫in n sequential slots.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2004년도 추계 학술발표회 논문집
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• pp.133-138
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• 2004

Proton exchange membrane fuel cell (PEMFC) is considered as a clean and efficient energy conversion det ice for mobile and stationary applications. Anions all the components of the PEMFC, the interface between the electrolyte ,and electrode catalyst plays an important role in determining tile cell performance since the electrochemical reactions take place at the interface in contact with tile reactant gases. Therefore, to increase the interface area and obtain a high-performance PEMFC, surface of the electrolyte membrane was roughened by Ar$^{+}$ beam bombardment. The results imply that by modifying surface of the electrolyte membrane, platinum loading can be reduced significantly without performance loss. To optimize the surface treatment condition, effects of ion dose density on characteristics of the membrane/electrode interface were examined by measuring the cell performance, impedance spectroscopy, and cyclic voltammograms. Surface of the modified membranes were characterized using scanning electron microscopy and FT-IR.R.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.676-680
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• 1994

Three synchronic variables (Deviation Time, Fairness Time, Synchronic Time) are defined for Timed Place Petri Nets (TPPN). These parameters show the dependency between the firing of transition subsets in the time domain by different values. The approaches in this paper can be used to find synchronic relations in Stochastic Petri Nets. This paper presents how to decide the minimum resources required to a Flexible Manufacturing Cell using Synchronic Time concept.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.200-206
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• 2014

This paper describes magnetically levitated vehicle with hybrid magnets, which have been studied by the authors in place of streetcars or conveyance system. An experimental vehicle of 20kg was magnetically levitated by using a small number of dry-cell batteries, which consisted of 10 Ni-MH cells of 1900mAh in series. The magnets were activated sequentially, because the internal resistance of the batteries suppressed the maximum current. The vehicle was kept levitating for about 2 hours and was stable against disturbance due to instantaneous external force. In this paper, dynamic characteristics of the magnetically levitated vehicle using a small number of dry cell batteries are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.3-12
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• 1991

Fuel cells are electrochemical devices that convert the chemical reaction energy directly into the electrical energy. In a typical fuel cell, gaseous fuel is fed continuously to the anode(negative electrode) compartment and the oxidant(i.e, oxygen from air) is fed continuously to the cathode(positive electrode) compartment; the electrochemical reactions take place at the electrodes to produce an electric current. Many of the operational characteristics of fuel cell systems are superior to those of conventional power generation system because of good efficiency, environmental protection, safty, modularity etc. From those reasons, the fuel cells are considered to be the solution to the future problem of energy conversion. The objective of this paper is to introduce the technical status of fuel cell technologies and our national project for the development of the phosporic acid fuel cell.

• Journal of Plant Biotechnology
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• 제1권1호
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• pp.56-60
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• 1999

Sexual reproduction is an essential process in the propagation of flowering plants. Recent advances in plant cell biology and biotechnology have brought new and powerful methodologies to investigate and manipulate the reproductive processes of angiosperms including agronomically important crop plants. Successful cryopreservation of maize, rye and triticale pollen and young embryos of microspore-and zygote-origine contributes to long term preservation of important plant germ-lines in gene banks. Discovering morphogenetic characteristics of the different developmental pathways taking place in wheat and maize androgenesis in vitro helps to influence the procedure to produce genetically and phenotipically stable homozygous doubled haploid plants for breeding purposes. Detailed ultrastructural and cell-biological studies on the developmental sequences of male and female gametophyte development in wheat, experimental protocols developed to isolate and micromanipulate egg cell protoplasts, make it possible to use plant gametes and the sexual route itself to produce genetically improved organisms. Plant gametes can become useful tools for crop improvement in the near future. Recent achievements by our laboratory in this field are reviewed in the present paper