• The Korean Journal of Physiology and Pharmacology
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• 제18권6호
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• pp.447-456
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• 2014

Until now, a disease-modifying therapy (DMT) that has an ability to slow or arrest Alzheimer's disease (AD) progression has not been developed, and all clinical trials involving AD patients enrolled by clinical assessment alone also have not been successful. Given the growing consensus that the DMT is likely to require treatment initiation well before full-blown dementia emerges, the early detection of AD will provide opportunities to successfully identify new drugs that slow the course of AD pathology. Recent advances in early detection of AD and prediction of progression of the disease using various biomarkers, including cerebrospinal fluid (CSF) $A{\beta}_{1-42}$, total tau and p-tau181 levels, and imagining biomarkers, are now being actively integrated into the designs of AD clinical trials. In terms of therapeutic mechanisms, monitoring these markers may be helpful for go/no-go decision making as well as surrogate markers for disease severity or progression. Furthermore, CSF biomarkers can be used as a tool to enrich patients for clinical trials with prospect of increasing statistical power and reducing costs in drug development. However, the standardization of technical aspects of analysis of these biomarkers is an essential prerequisite to the clinical uses. To accomplish this, global efforts are underway to standardize CSF biomarker measurements and a quality control program supported by the Alzheimer's Association. The current review summarizes therapeutic targets of developing drugs in AD pathophysiology, and provides the most recent advances in the clinical utility of CSF biomarkers and the integration of CSF biomarkers in current clinical trials.

• Advances in nano research
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• 제10권3호
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• pp.253-261
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• 2021

Polydimethylsiloxane (PDMS) is one of the most widely adopted silicon-based organic polymeric elastomers. Elastomeric nanostructures are normally required to accomplish an explicit mechanical role and correspondingly their mechanical properties are crucial to affect device and material performance. Despite its wide application, the mechanical properties of PDMS are yet fully understood. In particular, the time dependent mechanical response of PDMS has not been fully elucidated. Here, utilizing state-of-the-art PeakForce Quantitative Nanomechanical Mapping (PFQNM) together with Force Volume (FV) and Fast Force Volume (FFV), the elastic moduli of PDMS samples were assessed in a time-dependent fashion. Specifically, the acquisition frequency was discretely changed four orders of magnitude from 0.1 Hz up to 2 kHz. Careful calibrations were done. Force data were fitted with a linearized DMT contact mechanics model considering surface adhesion force. Increased Young's modulus was discovered with increasing acquisition frequency. It was measured 878 ± 274 kPa at 0.1 Hz and increased to 4586 ± 758 kPa at 2 kHz. The robust local probing of mechanical measurement as well as unprecedented high-resolution topography imaging open new avenues for quantitative nanomechanical mapping of soft polymers, and can be extended to soft biological systems.

• 한국통신학회논문지
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• 제26권12C호
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• pp.233-239
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• 2001

ADSL G.LITE 모뎀이 수행하는 주파수 영역의 연산과정에서 하향링크에 대한 FET 과정과 FEQ 과정은 가장 많은 연산량을 차지하는 부분이며, 이를 효율적으로 구현하기 위한 연구들이 수행되었다. 기존의 연구는 ADSL G.DMT 방식에 적합한 시스템으로서 G.LITE에 그대로 적용하기에는 부적합하다. 본 논문에서는 주파수 영역의 연산과정을 분석하고, 하드웨어 자원 할당에 따른 시스템의 효율성을 분석하여 G.LITE 방식에 적합한 프로세서의 구조를 제안하였다. 제안된 프로세서는 1개의 실수 곱셈기와 2개의 실수 덧셈기를 병렬로 연결한 구조를 가지며, 파이프라인 형태 및 병렬연산 형태의 작업 스케쥴링을 통해 효율적으로 연산을 수행할 수 있도록 설계되었다. 제안된 프로세서는 Kiss가 제안한 ALU 구조나 Wang이 제안한 FFT/IFFT 프로세서 구조에 비해 적은 하드웨어 자원을 이용하여 연산과정을 효율적으로 수행함으로서 G.LITE 시스템에 적합한 구조를 갖는다.

• 전기학회논문지P
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• 제52권4호
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• pp.148-153
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• 2003

In this paper, the low voltage 3V Sigma-Delta Digital Analog Converter(DAC) is designed for using in the transmitter of ADSL analog front-end. We have developed the CMOS DAC according to ANSI T1.413-2(DMT) standard specifications of the chip. The designed 4th-order DAC is composed of three block which are 1-bit DAC, 1st-order Switched-Capacitor filter and analog active 2nd-order Resistor-Capacitor(RC) filter. The HSPICE simulation of the designed DAC showing 65db SNR, is connected with 1.1MHz continuous lowpass filter. And also, we have performed the circuits verification and layout verification(ERC, DRC, LVS) followed by fabrication using TSMC 2-poly 5-metal p-substrate CMOS $0.35{\mu}m$ processing parameter. Finally, the chip testing has been performed and presented in the results.

• 한국환경보건학회지
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• 제39권1호
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• pp.1-18
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• 2013

Objectives: Although a great body of knowledge is available on the toxicity of bisphenol A (BPA), little is known about that of BPA alternatives, such as bisphenol analogues (BPs) or $Tritan^{TM}$ copolyesters. This review provides a summary of the available information on the toxicity of BPs and three components of $Tritan^{TM}$, with a special focus on endocrine disruption. Methods: We collected from the literature a battery of in vitro and in vivo assay data developed to assess endocrine disruption of four BPs (bisphenol AF, B, F, and S) and three major components of $Tritan^{TM}$ ((di-methylterephthalate (DMT), 1,4-cyclohexanedimethanol (CHDM), and 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD)). Results: Several alternative compounds were identified as possessing comparable or even greater endocrinedisrupting effects than BPA in in vitro and in vivo studies. Conclusions: Potential endocrine disruption of BPA alternatives requires further studies on health consequences in experimental animals and in humans following longer term exposure.

• 폴리머
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• 제36권4호
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• pp.440-447
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• 2012

분지화된 폴리에스테르계 공중합체를 제조하고, 공중합체의 분자량, 용융점도, $T_g$, 1/2 method temperature($T_{1/2}$) 및 레올로지 특성을 고찰하여 레이저 프린터 토너 바인더로의 적용을 검토하였다. 디메틸테레프탈레이트(DMT), 에틸렌글리콜(EG), 2,2-bis(4-(2-hydroxypropoxy)phenyl)propane(HPP)으로 제조한 선형공중합체는 분자량이 낮고, 용융탄성이 낮아 이를 개선하기 위하여 분지제로 3 또는 4 관능기를 가진 2-(hydroxymethyl)-2-ethylpropane-1,3-diol(trimethylol propane, TMP), 2,2-bi(hydroxymethyl)-1,3-propanediol(pentaerythritol, PER), 1,2,4-benzenetricarboxylic anhydride(trimellitic anhydride, TMA), 글리세롤 등을 첨가하여 분지화된 공중합체를 제조하였다. 분지제의 함량과 종류에 따른 열적, 레올로지 특성을 고찰하였다. 분지제의 함량이 15 mol% 이상 첨가한 공중합체는 $140^{\circ}C$ 정도의$T_{1/2}$ 값을 가지고, 높은 분자량과 용융탄성을 나타내어 토너를 융착 인쇄하는 레이저 프린터의 핫멜트 토너로서 적당하였다.

• 한국해양공학회지
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• 제22권1호
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• pp.1-5
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• 2008

A 2-D Fluent-based numerical wave tank(FBNWT) capable of simulating wave propagating and overtopping is presented. The FBNWT model is based on the Reynolds averaged Naiver-Stokes equations and VOF free surface tracking method. The piston wave maker system is realized by dynamic mesh technology(DMT) and user defined function(UDF). The non-iteration time advancement(NITA) PISO algorithm is employed for the velocity and pressure coupling. The FBNWT numerical solutions of linear wave propagation have been validated by analytical solutions. Several overtopping problems are simulated and the prediction results show good agreements with the experimental data, which demonstrates that the present model can be utilized in the corresponding analysis.

• Journal of Communications and Networks
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• 제1권2호
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• pp.86-88
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• 1999

The Discrete Fourier Transform (DFT) and the Inverse Discrete Fourier Transform (IDFT) are commonly used in signal processing applications, in particular in digital communication sys-tems using the multi-carrier modulation principle. In such systems an IDFT is computed at the transmitter end, and a DFT at the re-ceiver end. This paper examines a technique of computations, for which only negligible differences appear between the DFT and the IDFT calculations while the number of arithmetic operations re-quired is substantially reduced. This offers significant advantages for the design of an IDFT/DFT processor for Discrete Multitone(DMT) systems.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.293.3-294
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• 2002

In the brain, glial cells serve in the role to sequester metal from the neural microenvironment and therefore play an important role as a cellular deposition site. The central nervous system is highly vulnerable to oxidative stress, and free iron can stimulate oxidative stress by the Fenton reaction. Aluminum may upregulates the transferrin-independent iron uptake system and stimulate oxidative stress. Nramp2. also known as DMT 1. is a 12-transmembrane(TM) domain protein responsible for dietary iron uptake as well as metal ions such as iron. lead, mangamese. zinc. copper, and cobait. (omitted)

• Macromolecular Research
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• 제8권6호
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• pp.261-267
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• 2000

It is well known that poly(cyclohexylene dimethylene terephthalate) (PCT) is used as the engineering plastics with high melting temperature and fast crystallization rate compared with poly(butylene terephthalate)(PBT). However, poor thermal stability of PCT has limited its practical application due to the drastic decrease of molecular weight during the processing temperature. In order to improve the thermal stability of PCT homopolymer, the copolymer of PCT and PBT was synthesized and the thermal properties of the copolymer have been studied. P(CT/BT) copolymer was obtained by condensation polymerization of DMT, CHDM, and 1,4-butanediol. The chemical structure and composition of the copolymer was investigated by FTIR and NMR analysis. The thermal behavior of copolymer was studied using DSC and it was found that the crystallization-melting behavior of the copolymer was observed for the whole composition range. TGA analysis exhibited that P(CT/BT) copolymer is more stable at the initial stage of thermal decomposition compared with PCT and PBT homopolymers.