• 식물조직배양학회지
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• 제27권6호
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• pp.423-428
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• 2000

In 1997 when cloned sheep Dolly and soon after Polly were born, it had become head-line news because in the former the nucleus that gave rise to the lamb came from cells of six-year-old adult sheep and in the latter case a foreign gene was inserted into the donor nucleus to make the cloned sheep produce human protein, factor IX, in e milk. In the last few years, once the realm of science fiction, cloned mammals especially in livestock have become almost commonplace. What the press accounts often fail to convey, however, is that behind every success lie hundreds of failures. Many of the nuclear-transferred egg cells fail to undergo normal cell divisions. Even when an embryo does successfully implant in the womb, pregnancy often ends in miscarriage. A significant fraction of the animals that are born die shortly after birth and some of those that survived have serious developmental abnormalities. Efficiency remains at less than one % out of some hundred attempts to clone an animal. These facts show that something is fundamentally wrong and enormous hurdles must be overcome before cloning becomes practical. Cloning researchers now tent to put aside their effort to create live animals in order to probe the fundamental questions on cell biology including stem cells, the questions of whether the hereditary material in the nucleus of each cell remains intact throughout development, and how transferred nucleus is reprogrammed exactly like the zygotic nucleus. Stem cells are defined as those cells which can divide to produce a daughter cell like themselves (self-renewal) as well as a daughter cell that will give rise to specific differentiated cells (cell-differentiation). Multicellular organisms are formed from a single totipotent stem cell commonly called fertilized egg or zygote. As this cell and its progeny undergo cell divisions the potency of the stem cells in each tissue and organ become gradually restricted in the order of totipotent, pluripotent, and multipotent. The differentiation potential of multipotent stem cells in each tissue has been thought to be limited to cell lineages present in the organ from which they were derived. Recent studies, however, revealed that multipotent stem cells derived from adult tissues have much wider differentiation potential than was previously thought. These cells can differentiate into developmentally unrelated cell types, such as nerve stem cell into blood cells or muscle stem cell into brain cells. Neural stem cells isolated from the adult forebrain were recently shown to be capable of repopulating the hematopoietic system and produce blood cells in irradiated condition. In plants although the term$\boxDr$ stem cell$\boxUl$is not used, some cells in the second layer of tunica at the apical meristem of shoot, some nucellar cells surrounding the embryo sac, and initial cells of adventive buds are considered to be equivalent to the totipotent stem cells of mammals. The telomere ends of linear eukaryotic chromosomes cannot be replicated because the RNA primer at the end of a completed lagging strand cannot be replaced with DNA, causing 5' end gap. A chromosome would be shortened by the length of RNA primer with every cycle of DNA replication and cell division. Essential genes located near the ends of chromosomes would inevitably be deleted by end-shortening, thereby killing the descendants of the original cells. Telomeric DNA has an unusual sequence consisting of up to 1,000 or more tandem repeat of a simple sequence. For example, chromosome of mammal including human has the repeating telomeric sequence of TTAGGG and that of higher plant is TTTAGGG. This non-genic tandem repeat prevents the death of cell despite the continued shortening of chromosome length. In contrast with the somatic cells germ line cells have the mechanism to fill-up the 5' end gap of telomere, thus maintaining the original length of chromosome. Cem line cells exhibit active enzyme telomerase which functions to maintain the stable length of telomere. Some of the cloned animals are reported prematurely getting old. It has to be ascertained whether the multipotent stem cells in the tissues of adult mammals have the original telomeres or shortened telomeres.

• 폴리머
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• 제32권2호
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• pp.150-156
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• 2008

Two different polyacrylonitrile samples (PANs, triad tacticity fraction is 0.25 and 0.64) were synthesized and used to study the kinetics of cyclization. Polymers were treated at different temperatures between 250 to $300^{\circ}C$ under air atmosphere, and analyzed by X-ray diffractometer. The sharp and strong peak at $2{\theta}=16.5^{\circ}$ corresponds to a lateral repeat distance that is the (100) diffraction in hexagonal lattice, while the peak at $2{\theta}=25.5^{\circ}$ reflects the (101) diffraction. In comparing their areas of different heat treated samples, the cyclization of both PANs was identified as a first-order reaction. The rate constants of cyclization reaction at different temperatures and the active energy parameter were obtained. This results might provide an important effect on pre-oxidation of polyacrylonitrile fiber.

• Structural Engineering and Mechanics
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• 제11권2호
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• pp.199-210
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• 2001

Axially compressed circular cylinders repeat symmetry-breaking bifurcation in the postbuckling region. There exist stable equilibria with all symmetry broken in the buckled configuration, and the minimum postbuckling strength is attained at the deep bottom of closely spaced equilibrium branches. The load level corresponding to such postbuckling stable solutions is usually much lower than the initial buckling load and may serve as a strength limit in shell stability design. The primary concern in the present paper is to compute these possible postbuckling stable solutions at the deep bottom of the postbuckling region. Two computational approaches are used for this purpose. One is the application of individual procedures in computational bifurcation theory. Path-tracing, pinpointing bifurcation points and (local) branch-switching are all applied to follow carefully the postbuckling branches with the decreasing load in order to attain the target at the bottom of the postbuckling region. The buckled shell configuration loses its symmetry stepwise after each (local) branch-switching procedure. The other is to introduce the idea of path jumping (namely, generalized global branch-switching) with static imperfection. The static response of the cylinder under two-parameter loading is computed to enable a direct access to postbuckling equilibria from the prebuckling state. In the numerical example of an elastic perfect circular cylinder, stable postbuckling solutions are computed in these two approaches. It is demonstrated that a direct path jump from the undeformed state to postbuckling stable equilibria is possible for an appropriate choice of static perturbations.

• Journal of Information Processing Systems
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• 제12권1호
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• pp.46-56
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• 2016

Dynamic textures are videos that exhibit a stationary property with respect to time (i.e., they have patterns that repeat themselves over a large number of frames). These patterns can easily be tracked by a linear dynamic system. In this paper, a model that identifies the underlying linear dynamic system using wavelet coefficients, rather than a raw sequence, is proposed. Content based threshold filtering based on Set Partitioning in a Hierarchical Tree (SPIHT) helps to get another representation of the same frames that only have low frequency components. The main idea of this paper is to apply SPIHT based threshold filtering on different bands of wavelet transform so as to have more significant information in fewer parameters for singular value decomposition (SVD). In this case, more flexibility is given for the component selection, as SVD is independently applied to the different bands of frames of a dynamic texture. To minimize the time complexity, the proposed model is implemented on a graphics processing unit (GPU). Test results show that the proposed dynamic system, along with a discrete wavelet and SPIHT, achieve a highly compact model with better visual quality, than the available LDS, Fourier descriptor model, and higher-order SVD (HOSVD).

• 한국의류학회지
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• 제36권5호
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• pp.573-582
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• 2012

This work is to develop a T-shirt by adopting a unique cloud pattern (a good auspicious sign as design material) from traditional native Korean patterns for application to various cultural products and textile design cloth patterns; subsequently, a T-shirt design was processed based on this. As a research method, computer design programs Adobe Illustrator CS3 and Adobe Photoshop CS3 were used along with a literature examination as part of motive for design development and pattern realization. Three basic motives were selected as a new formative image in this work, utilizing graphical elements such as abridgement and simplicity of pattern, where flower-shaped cloud pattern, uprising cloud pattern, and 卍-shaped or swastika-shaped pattern of traditional cloud patterns were selected. Each motive diverged into two motives via the shape transformation and the application of different colors. The newly developed basic motive was further processed into a combination of one-time repeat pattern, stripe pattern, and application pattern with mixed cloud motives (that were previously developed), which altogether turned out to be 36 pieces of textile design. In addition, with newly developed motive designs and textile designs, a total of 12 shirt designs for 4 pieces were developed for these three each. The shirt design was developed into a shirt blouse, sleeveless T-shirt, half-sleeve T-shirt, and sports T-shirt among others in order to fit various uses and purposes.

• 대한디지털의료영상학회논문지
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• 제12권1호
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• pp.43-50
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• 2010

The representative study of Patellofemoral Joint Merchant method can show the view for inspection of the sulcus angle, congruence angle and diagnose whether there are the vertical fractures and recognize the degree of dislocation and patella subluxation. However, anatomical correlation about the degree of knee joint curvature changes during position adjustment and distortion of the image reduces reproducibility. In order to resolve these problems, Merchant method needs to use assisting device which reduces the occurrence of repeat projection and effectively to increase unification of examination and the consistency of the image. However, there are disadvantages for patients who take other examinations. For example, they have to change the position for every examination and it might cause the patient's discomfort and increase of examination time. In this study, we newly devised commercial assisting device which improves the reproducibility of the images and reduces inconvenience of patients movement. Further research should be taken to obtain a image without patient's movement and to reduce the time of the examination than existing method.

• 한국콘텐츠학회논문지
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• 제11권6호
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• pp.311-325
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• 2011

청소년 범죄는 사소한 비행에서 시작되어 재범을 반복하는 생활을 하기 쉬운 첫 단계로 초기 단계에서 적극적인 선도대책을 시행함으로써 청소년 범죄를 감소시킬 수 있는 방안 마련이 시급하다. 비행 소년 범법 소년 사건처리에서 가장 중요한 것은 법적인 절차로 판단을 내리는 것 보다는 선도절차에 초점을 맞추어 재범을 방지하고 사회의 정상적인 구성원으로 복귀시키는 것이 최상의 방안이다. 이러한 맥락에서, 비행소년 범법 소년의 재범률 감소를 위한 다이버전 프로그램 개발 및 활성화 방안으로 전문가 활성화 및 초범에 대한 적절한 대응, 부모교육의 필요성, 멘토의 활성화, 후속 프로그램 개발을 제시하였다.

• BMB Reports
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• 제32권5호
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• pp.468-473
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• 1999

Nuclear Factor 1 (NF1) proteins are a family of transcriptional factors consisting of four different types: NF1-A, -B, -C, and -X. Some NF1 transcription factors contain a heptasequence motif, SPTSPSY, which is found as a repeat sequence in the carboxy terminal domain (CTD) of the largest subunit of RNA polymerase II. A similar heptasequence, SPTSPTY, is contained in rat liver NF1-A at a position between residues 469 and 475. In order to investigate the roles of the individual amino acids of the heptasequence of rat liver NF1-A in transcriptional activation, we systematically substituted single and multiple amino acid residues with alanine residue(s) and evaluated the transcriptional activities of the mutated NF1-A. Substitution of a single amino acid reduced transcriptional activity by 10 to 30%, except for the proline residue at position 473, whose substitution with alanine did not affect transcriptional activity. However, changes of all four serine and threonine residues to alanine or of the tyrosine residue along with the serine residue at position 469 to alanine reduced the activity to almost background levels. Our results indicate that multiple serine and threonine residues, rather than a single residue, may be involved in the modulation of the transcriptional activities of the factor. Involvement of the tyrosine residue is also implicated.

• 한국의류산업학회지
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• 제19권5호
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• pp.595-601
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• 2017

Advances in 3D garment simulation technology contribute greatly to consumers becoming more immersed in movies and games by realistically expressing the garments the characters in the movie or game are wearing. The fashion industry has reached a point where it needs to maximize efficiency in production and distribution to go beyond time and space in order to compete on the global market. The processes of design and product development in the fashion industry require countless hours of work and consume vast resources in terms of materials and energy to repeat sample production and assessment. Therefore, the design and product development tools and techniques must aim to reduce the sample making process. Therefore, this study aims to study a case for comparing the real garment sample making process to the virtual garment sample making process. In this study, we have analysed the differences between the real and virtual garment making processes by choosing designated patterns. As we can see from the study results, the real and virtual garments generally are made through similar processes in manufacturing, while the time consumed for each shows great variation. In real garment making, scissoring and sewing require the greatest number of work hours, whereas in virtual garment making, most of the time was spent in the simulation process.

• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1044-1049
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• 2008

In order to study functional nucleotides in prototype foamy virus (PFV) DNA on specific recognition by PFV integrase (IN), we designed chimeric U5 long terminal repeat (LTR) DNA substrates by exchanging comparative sequences between human immunodeficiency virus type-1 (HIV-1) and PFV U5 LTRs, and investigated the 3'-end processing reactivity using HIV-1 and PFV INs, respectively. HIV-1 IN recognized the nucleotides present in the fifth and sixth positions at the 3'-end of the substrates more specifically than any other nucleotides in the viral DNA. However, PFV IN recognized the eighth and ninth nucleotides as distinctively as the fifth and sixth nucleotides in the reactions. In addition, none of the nucleotides present in the twelfth, sixteenth, seventeenth, eighteenth, nineteenth, and twentieth positions were not differentially recognized by HIV-1 and PFV INs, respectively. Therefore, our results suggest that the functional nucleotides that are specifically recognized by its own IN in the PFV U5 LTR are different from those in the HIV-1 U5 LTR in aspects of the positions and nucleotide sequences. Furthermore, it is proposed that the functional nucleotides related to the specific recognition by retroviral INs are present inside ten nucleotides from the 3'-end of the U5 LTR.