• Journal of the Korean Magnetic Resonance Society
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• 제27권1호
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• pp.1-4
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• 2023

Transthyretin (TTR) is an indispensable transporter protein of thyroxine and a retinol molecule in humans. TTR has a stable homo-tetrameric structure in its native state, while upon dissociation into monomers, it becomes aggregation-prone and can form an amyloid fibril. Although the amyloidogenic propensity of TTR has been known and investigated since the late 1990s, the structural information regarding TTR's amyloidogenic species is still elusive. Here, we employed high-pressure nuclear magnetic resonance (HP-NMR) approaches on the monomeric variant of TTR (TTR[F87M/L110M]; M-TTR) and observed that it experiences a two-step transition in response to the pressurized condition. Our study demonstrated that M-TTR in an ambient condition has heterogeneous structural features, which is likely related to the amyloidogenic propensity of TTR.

• Journal of the Korean Magnetic Resonance Society
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• 제24권3호
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• pp.91-95
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• 2020

Transthyretin (TTR) is an abundant protein in blood plasma and cerebrospinal fluid (CSF), working as a homo-tetrameric complex to transport thyroxine (T₄) and a holo-retinol binding protein. TTR is well-known for its amyloidogenic property; several types of systemic amyloidosis diseases are caused by aggregation of either wild-type TTR or its variants, for which more than 100 mutations were reported to increase the amyloidogenicity of TTR. The rate-limiting step of TTR aggregation is the dissociation of a monomeric subunit from a tetrameric complex. A wide range of biochemical and biophysical techniques have been employed to elucidate the TTR aggregation processes, among which nuclear magnetic resonance (NMR) spectroscopy contributed much to characterize the structural and functional features of TTR during its aggregation processes. The present review focuses on discussing the recent advances of our understanding to the amyloidosis mechanism of TTR and to the structural features of its monomeric aggregation-prone state in solution. We expect that the present review provides novel insights to appreciate the molecular basis of TTR amyloidosis and to develop novel therapeutic strategies to treat diverse TTR-related diseases.

• Animal Bioscience
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• 제36권9호
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• pp.1367-1375
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• 2023

Objective: Pigment production and distribution are controlled through multiple proteins, resulting in different coat color phenotypes of sheep. Methods: The expression distribution of vimentin (VIM) and transthyretin (TTR) in white and black sheep skins was detected by liquid chromatography-electrospray ionization tandem MS (LC-ESI-MS/MS), gene ontology (GO) statistics, immunohistochemistry, Western blot, and quantitative real time polymerase chain reaction (qRT-PCR) to evaluate their role in the coat color formation of sheep. Results: LC-ESI-MS/MS results showed VIM and TTR proteins in white and black skin tissues of sheep. Meanwhile, GO functional annotation analysis suggested that VIM and TTR proteins were mainly concentrated in cellular components and biological process, respectively. Further research confirmed that VIM and TTR proteins were expressed at significantly higher levels in black sheep skins than in white sheep skins by Western blot, respectively. Immunohistochemistry notably detected VIM and TTR in hair follicle, dermal papilla, and outer root sheath of white and black sheep skins. qRT-PCR results also revealed that the expression of VIM and TTR mRNAs was higher in black sheep skins than in white sheep skins. Conclusion: The expression of VIM and TTR were higher in black sheep skins than in white sheep skins and the transcription and translation were unanimous in this study. VIM and TTR proteins were expressed in hair follicles of white and black sheep skins. These results suggested that VIM and TTR were involved in the coat color formation of sheep.

• ETRI Journal
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• 제32권2호
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• pp.230-240
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• 2010

The IEEE802.16j standard uses non-transparent relay stations to extend coverage. There are two types of non-transparent relay modes, that is, the time-division transmit and receive (TTR) relay mode which can operate with one of two types of frame structures, a single-frame and multiframe structure, and the simultaneous transmit and receive (STR) relay mode. In this paper, we analyze the relay performance of TTR and STR relay modes in IEEE 802.16j MMR system. We also propose a fair resource allocation scheme for the downlink relay frame. Numerical results show that relay performance of the TTR with a single-frame or a multiframe structure and that of the STR relay modes are almost the same in a two-hop system. However, in a three-hop system, the TTR mode with a single-frame structure outperforms other relay modes.

• Proceedings of the KOSOMBE Conference
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.55-59
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• 1989

A true three-dimensional cone-beam reconstruction (TTCR) algorithm for the complete sphere geometry is derived, which is applicable to the direct volume image reconstruction from 2-D cone-beam projections. The algorithm is based on the modified filtered backprojection technique which uses a set of 2-D space-invariant filters and is derived from the previously developed parallel-beam true three-dimensional reconstruction(TTR) algorithm. The proposed algorithm proved to be superior in spatial resolution compared with the parallel-beam TTR algorithm.

• Journal of the Korean Magnetic Resonance Society
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• 제25권1호
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• pp.8-11
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• 2021

Transthyretin (TTR) is an important transporter protein for thyroxine (T4) and a holo-retinol protein in human. In its native state, TTR forms a tetrameric complex to construct the hydrophobic binding pocket for T4. On the other hand, this protein is also infamous for its amyloidogenic propensity, which causes various human diseases, such as senile systemic amyloidosis and familial amyloid polyneuropathy/cardiomyopathy. In this work, to investigate various structural features of TTR with solution-state nuclear magnetic resonance (NMR) spectroscopy, we conducted backbone NMR signal assignments. Except the N-terminal two residues and prolines, backbone 1H-15N signals of all residues were successfully assigned with additional chemical shift information of 13CO, 13Cα, and 13Cβ for most residues. The chemical shift information reported here will become an important basis for subsequent structural and functional studies of TTR.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제41권7호
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• pp.621-627
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• 2017

The understanding of the mechanical properties of amyloid fibers, which induce various neurodegenerative diseases, is directly related to the amyloid growth mechanism. Diverse studies have been performed on amyloid fibers from the viewpoint of disease epidemiology. Recently, attempts have been made to use amyloid fibers as new materials because of their notable mechanical properties and self-aggregation abilities. In this study, the mechanical properties of transthyretin (TTR105-115), which induces cardiovascular disease, were evaluated using a molecular dynamics (MD) simulation. In particular, the effect of the end-terminal capping on the structural stability of TTR105-115 was evaluated. The mechanical behavior and properties of TTR105-115 were measured by steered molecular dynamics (SMD). We clarified the factors affecting the mechanical properties of these materials and suggested the possibility of utilizing them as nature inspired materials.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.88-93
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• 2017

For the control of pre-burner combustion pressure, the open angle of TTR(Throttle for Thrust Regulation) valve was varied from $143^{\circ}$ to $185^{\circ}$ while testing of cold flow, ignition, combustion. The major performance variables of rocket engine and hydraulic performance of TTR valve regarding the open angle was verified. However the controllability of pre-burner combustion pressure was not verified due to the limitations of test. The comprehensive research will be done after supplementing these problems.

• Structural Monitoring and Maintenance
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• 제6권4호
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• pp.365-387
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• 2019

This study aims to provide useful information on the fatigue assessment of a top-tensioned riser (TTR) subjected to vortex-induced vibration (VIV) by performing parametric study. The effects of principal design parameters, i.e., riser diameter, wall thickness, water depth (related to riser length), top tension, current velocity, and shear rate (or shear profile of current) are investigated. To prepare the base model of TTR for parametric studies, three (3) riser modelling techniques in the OrcaFlex were investigated and validated against a reference model by Knardahl (2012). The selected riser model was used to perform parametric studies to investigate the effects of design parameters on the VIV fatigue damage of TTR. From the obtained comparison results of VIV analysis, it was demonstrated that a model with a single line model ending at the lower flex joint (LFJ) and pinned connection with finite rotation stiffness to simulate the LFJ properties at the bottom end of the line model produced acceptable prediction. Moreover, it was suitable for VIV analysis purposes. Findings from parametric studies showed that VIV fatigue damage increased with increasing current velocity, riser outer diameter and water depth, and decreased with increasing shear rate and top tension of riser. With regard to the effects of wall thickness, it was not significant to VIV fatigue damage of TTR. The detailed outcomes were documented with parametric study results.

• Journal of Korean language education
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• 제28권4호
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• pp.245-271
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• 2017

This study aimed at investigating the lexical diversity in the "Frog Story" narratives of Korean-Chinese bilingual children. Six bilingual speakers of Korean children- four boys and two girls- were audio recorded as they produced narratives based on pictures from the Mercer Mayer book "Frog, where are you?" The order of narration was counterbalanced. The vocabularies from narratives were analyzed by type, token, TTR (type-token Ratio) and D value using the CLAN (Computerized Language Analysis) program. The findings showed that the pattern of lexical diversity in Korean is similar with the Chinese, but the TTR and D value of Chinese still remain low in comparison with those of Korean. In addition, Korean language seems to have significant influence on Chinese in the language usage pattern and vice versa.