• Molecules and Cells
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• v.22 no.2
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• pp.127-132
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• 2006

In the post genome project era, it is well established that the human genome contains a smaller number of genes than expected. The complexity found in higher organisms can be explained if proteins are multifunctional. Indeed, recent studies are continuing to reveal proteins that are capable of a broad repertoire of functions. A good paradigm for multifunctionality can be found in the amino-acyl tRNA synthetases (aaRSs), an ancient conserved family of proteins. This unique family, which is comprised of 20 different enzymes, is well known for its participation in protein synthesis. Several studies have described numerous examples of these "housekeeping" proteins taking part in extensive critical cellular activities. In this review, we focus on a member of that family, lysyl-tRNA synthetase (LysRS), which has been shown to have a dual functionality. In addition to its contribution to the translation process, LysRS also takes part in the regulation of MITF and USF2 target genes. This phenomenon was first described in mast cells.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.23-34
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• 2001

Purpose : To develop a new subtraction program for registering digital periapical images based on the correspondence of anatomic structures. Materials and Methods: The digital periapical images were obtained by Digora system with Rinn XCP equipment after translation of 1-16 mm, and rotation of 2-20° at the premolar and molar areas of the human dried mandible. The new subtraction program, NIH Image program and Emago/Advanced program were compared by the peak-signal-to noise ratio (PSNR). Results : The new subtraction program was superior to NIH Images program and Emagol Advanced program up to 16 mm translation and horizontal angulation up to 4°. Conclusion: The new subtraction program can be used for subtracting digital periapical images.

• Molecules and Cells
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• v.43 no.10
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• pp.848-855
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• 2020

Cells assemble stress granules (SGs) to protect their RNAs from exposure to harmful chemical reactions induced by environmental stress. These SGs release RNAs, which resume translation once the stress is relieved. During stem cell differentiation, gene expression is altered to allow cells to adopt various functional and morphological features necessary to differentiate. This process induces stress within a cell, and cells that cannot overcome this stress die. Here, we investigated the role of SGs in the progression of stem cell differentiation. SGs aggregated during the neuronal differentiation of human bone marrow-mesenchymal stem cells, and not in cell lines that could not undergo differentiation. SGs were observed between one and three hours post-induction; RNA translation was restrained at the same time. Immediately after disassembly of SGs, the expression of the neuronal marker neurofilament-M (NF-M) gradually increased. Assembled SGs that persisted in cells were exposed to salubrinal, which inhibited the dephosphorylation of eukaryotic translation initiation factor 2 subunit 1 (eIF2α), and in eIF2α/S51D mutant cells. When eIF2α/S51A mutant cells differentiated, SGs were not assembled. In all experiments, the disruption of SGs was accompanied by delayed NF-M expression and the number of neuronally differentiated cells was decreased. Decreased differentiation was accompanied by decreased cell viability, indicating the necessity of SGs for preventing cell death during neuronal differentiation. Collectively, these results demonstrate the essential role of SGs during the neuronal differentiation of stem cells.

• BMB Reports
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• v.35 no.3
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• pp.273-282
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• 2002

Sp3 is a bifunctional transcription factor that has been reported to stimulate or repress the transcription of numerous genes. Although the size of Sp3 mRNA is 4.0kb, the size of the known Sp3 cDNA sequence is 3.6kb. Thus, Sp3 functional studies have been performed with an artificially introduced start codon, and thus an amino-terminus that differs from the wild-type. Ideally, full-length cDNA expression vectors with the appropriate start codon should be utilized for these studies. Using 5'rapid amplification of cDNA ends, a full-length Sp3 cDNA clone was generated and the sequence verified in nine cell lines. No AUG initiation codon was present. However, stop codons were present in all three frames 5' to the known coding sequence. In vitro translation of this full-length cDNA clone produced the expected three isoforms-one at 100 kDa and two in the mid 60 kDa range. Electrophoretic mobility shift assays showed that the protein products had the ability to bind to the Sp1/3 consensus sequence. In vitro studies, using our Sp3 clone and site directed mutagenesis, identified the translation initiation site for the larger isoform as AUA. AUA has not been previously described as an endogenous initiation codon in eukaryotes.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.345-352
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• 2006

The practical English-Korean machine translation system should be able to translate long sentences quickly and accurately. The intra-sentence segmentation method has been proposed and contributed to speeding up the syntactic analysis. This paper proposes the syntactic category prediction method using decision trees for getting accurate parsing results. In parsing with segmentation, the segment is separately parsed and combined to generate the sentence structure. The syntactic category prediction would facilitate to select more accurate analysis structures after the partial parsing. Thus, we could improve the parsing accuracy by the prediction. We construct features for predicting syntactic categories from the parsed corpus of Wall Street Journal and generate decision trees. In the experiments, we show the performance comparisons with the predictions by human-built rules, trigram probability and neural networks. Also, we present how much the category prediction would contribute to improving the translation quality.

• BMB Reports
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• v.52 no.7
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• pp.424-433
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• 2019

Autism spectrum disorder (ASD) is a complex neurodevelopmental monogenic disorder with a strong genetic influence. Idiopathic autism could be defined as a type of autism that does not have a specific causative agent. Among signalling cascades, mTOR signalling pathway plays a pivotal role not only in cell cycle, but also in protein synthesis and regulation of brain homeostasis in ASD patients. The present review highlights, underlying mechanism of mTOR and its role in altered signalling cascades as a triggering factor in the onset of idiopathic autism. Further, this review discusses how distorted mTOR signalling pathway stimulates truncated translation in neuronal cells and leads to downregulation of protein synthesis at dendritic spines of the brain. This review concludes by suggesting downstream regulators such as p70S6K, eIF4B, eIF4E of mTOR signalling pathway as promising therapeutic targets for idiopathic autistic individuals.

• KSBB Journal
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• v.11 no.2
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• pp.165-172
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• 1996

To obtain a correctly folded human proinsulin, export of proinsulin using Staphylococcal protein A signal sequence-mediated secretion pathway has been attempted in E.coli. A secretion operon for proinsulin was constructed by consecutively connecting T7 promoter, SPA ribosome binding site, SPA signal sequence gene, and human proinsulin gene. Little immunoreactive proinsulin was detected in the periplasmic space and. culture medium, and not even in cytoplasmic space. The qualitative analysis of transcribed proinsulin mRNA and the in vitro transcription/translation experiment suggests that the negligible level of proinsulin export appears to be due to intracellular degradation of proinsulin, rather than due to the blockage during translocation. However, expression of proinsulin fusion protein such as MBP-proinsulin could dramatically increase export of proinsulin in E.coli.

• Annual Conference on Human and Language Technology
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• 2001.10d
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• pp.523-529
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• 2001

한국어의 용언구 중에서 [명사]+[불특정 조사]+[용언]의 형태를 보이는 '공부를 하다' '잠이나 자다'와 같은 어구는 [명사]와 [동사]의 결합이 비교적 자유로워 기계번역 시스템에서 이들을 처리하고자 할 때 몇가지 애로점이 있다. 우선, 기계번역 시스템의 특성상 이와 같은 용언구를 하나의 어구로 인식해서 역문을 생성해야 하는데 이들을 일일이 사전에 수록하기 어렵다는 점을 지적할 수 있다. 또한 이들 어구에 포함된 [명사] 부분이 [한정사]의 수식을 받을 때 영어 역문에서는 해당 수식어를 원래의 수식어의 의미 그대로 생성할 수 없다는 것도 중요한 문제점이다. 이러한 문제점을 해결하기 위하여 본 연구에서는 [명사] 부분과 [용언] 부분을 각각의 품사 사전에서 탐색하여 품사별로 인식한 후에 다시 통사적으로 하나의 용언으로 인식시켜 해당 역문을 생성하는 처리 방법을 제안한다. 또한, [한정사]의 수식을 올바로 생성하기 위하여 이런 종류의 용언구들을 분류하여 그 분류에 따라 [한정사]를 변형 생성하는 방법을 제시한다.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1504-1508
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• 2003

The functional behavior of each body segments were investigated with respect to human standing posture when they were exposed to the horizontal vibration in the sagittal plane. This study is processed by experimental approach. The data is analyzed, both in the time domain and in the frequency domain. Random and multisinusoidal vibration was used as input. The ankle, hip, and head were employed as the significant body segments. High relative movements were present between hip and head, and there was no significant relationship between ankle and head. Variations of visual input produced a significant postural effect.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.135-138
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• 2007

In this paper, intelligent filtering methodology for masterarm translation signal is proposed. Fidelity and stability are contradicting factors in teleoperation. Human hand trembling filtering is one of the problems in telemanipulation field. During every operation the hand has a certain vibration that can affect the quality of teleoperation, especially in carrying FPD (Flat Panel for Display), nanomanipuation and other precise tasks. It is very important to study the kinesthetic perception of the human and to optimize the teleoperation system accordingly. To cancel out the influence of human's hand vibration the signal from the masterarm should be filtered. One of the feasible solutions is to use an intelligent filter, which is a very flexible instrument. Applying intelligent filtering methodology, we can use some heuristic methods to solve the filtering problem.