• Title/Summary/Keyword: Target degradation

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The Effect of Non-uniform Superheat on the Performance of a Multi-path Evaporator (다중 유로에서 과열도의 불균형에 따른 증발기의 성능 특성에 관한 연구)

  • 최종민;김용찬
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.12
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    • pp.1043-1048
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    • 2003
  • An experimental investigation was executed to determine the capacity degradation due to non-uniform refrigerant distribution in a multi-path evaporator. In addition, the possibility of recovering the capacity reduction by controlling the refrigerant distribution among refrigerant paths was assessed. The finned-tube evaporator, which had a three-path and three-depth-row, was tested by controlling inlet quality, exit pressure, and exit superheat for each refrigerant path. The capacity reduction due to superheat unbalance between each path was as much as 30%, even when the overall evaporator superheat was kept at a target value of 5.6$^{\circ}C$. It may indicate that the internal heat transfer within the evaporator assembly caused the partial capacity drop. For the evaporator having air mal-distributions, the maximum capacity reduction was found to be 8.7%. A 4.5% capacity recovery was obtained by controlling refrigerant distribution to obtain the target superheat at the outlet of each path.

Adaptive Particle Filter Design for Radome Aberration Error Compensation (레이돔 굴절 오차 보상을 위한 적응 파티클 필터 설계)

  • Han, Sang-Sul;Lee, Sang-Jeong
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.9
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    • pp.947-953
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    • 2011
  • Radome aberration error causes degradation of miss distance as well as stability of high maneuver missile system with RF seeker. A study about radome compensation method is important in this kind of missile system design. Several kinds of methods showed good compensation performance in their paper. Proposed adaptive Particle filter estimates line of sight rate excluding the radome induced error. This paper shows effectiveness of adaptive Particle filter as compensation method of radome aberration error. Robust performance of this filter depends on external aiding measurement, target acceleration. Tuning of system error covariance can make this filter unsensitive against the error of target acceleration information. This paper demonstrates practical usage of adaptive Particle filter for reducing miss distance and increasing stability against disturbance of radome aberration error through performance analysis.

Chemically Induced Cellular Proteolysis: An Emerging Therapeutic Strategy for Undruggable Targets

  • Moon, Seonghyeon;Lee, Byung-Hoon
    • Molecules and Cells
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    • v.41 no.11
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    • pp.933-942
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    • 2018
  • Traditionally, small-molecule or antibody-based therapies against human diseases have been designed to inhibit the enzymatic activity or compete for the ligand binding sites of pathological target proteins. Despite its demonstrated effectiveness, such as in cancer treatment, this approach is often limited by recurring drug resistance. More importantly, not all molecular targets are enzymes or receptors with druggable 'hot spots' that can be directly occupied by active site-directed inhibitors. Recently, a promising new paradigm has been created, in which small-molecule chemicals harness the naturally occurring protein quality control machinery of the ubiquitin-proteasome system to specifically eradicate disease-causing proteins in cells. Such 'chemically induced protein degradation' may provide unprecedented opportunities for targeting proteins that are inherently undruggable, such as structural scaffolds and other non-enzymatic molecules, for therapeutic purposes. This review focuses on surveying recent progress in developing E3-guided proteolysis-targeting chimeras (PROTACs) and small-molecule chemical modulators of deubiquitinating enzymes upstream of or on the proteasome.

On Reducing Estimation Error Caused by Variable Sampling Rate

  • Yoon, Gi-Bum;Yoon, Dong-Uk;Hanseok Ko
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.1080-1083
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    • 2000
  • In this paper, we show that a variation in sampling rate give rise to system performance degradation and propose a method to effectively reduce the error. We first capture the variation as a first order autoregressive (AR) model and project it as an additional sensor measurement noise. By considering that the sensor measurements include correlated noise, we perform a decorrelation process and then apply a standard Kalman filter (SKF) to estimate the target-state. As a result of the two-step procedure, we achieve a significant reduction in the target state estimation error.

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Critical Roles of Deubiquitinating Enzymes in the Nervous System and Neurodegenerative Disorders

  • Das, Soumyadip;Ramakrishna, Suresh;Kim, Kye-Seong
    • Molecules and Cells
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    • v.43 no.3
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    • pp.203-214
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    • 2020
  • Post-translational modifications play major roles in the stability, function, and localization of target proteins involved in the nervous system. The ubiquitin-proteasome pathway uses small ubiquitin molecules to degrade neuronal proteins. Deubiquitinating enzymes (DUBs) reverse this degradation and thereby control neuronal cell fate, synaptic plasticity, axonal growth, and proper function of the nervous system. Moreover, mutations or downregulation of certain DUBs have been found in several neurodegenerative diseases, as well as gliomas and neuroblastomas. Based on emerging findings, DUBs represent an important target for therapeutic intervention in various neurological disorders. Here, we summarize advances in our understanding of the roles of DUBs related to neurobiology.

Enigma of Small Peptides Ubiquitin and SUMO in Plants

  • Seo, Hak Soo
    • Korean Journal of Breeding Science
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    • v.42 no.4
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    • pp.339-343
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    • 2010
  • Post-translational covalent modifications by small molecules or peptides remodel target proteins. One such modification, made by ubiquitin or small ubiquitin-related modifier (SUMO), is a rapidly expanding field in cell signaling pathways. Ubiquitin attachment controls the turnover and degradation of target proteins while SUMO conjugation regulates their activity and function. Recent studies report many examples of cross-talk between ubiquitin and SUMO pathways, indicating that the boundary is no longer clear. Here, we review recent progress concerning how ubiquitin and SUMO participate in new regulatory roles in plant cell, and how ubiquitination and sumoylation control plant growth and development.

Application of particle filtering for prognostics with measurement uncertainty in nuclear power plants

  • Kim, Gibeom;Kim, Hyeonmin;Zio, Enrico;Heo, Gyunyoung
    • Nuclear Engineering and Technology
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    • v.50 no.8
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    • pp.1314-1323
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    • 2018
  • For nuclear power plants (NPPs) to have long lifetimes, ageing is a major issue. Currently, ageing management for NPP systems is based on correlations built from generic experimental data. However, each system has its own characteristics, operational history, and environment. To account for this, it is possible to resort to prognostics that predicts the future state and time to failure (TTF) of the target system by updating the generic correlation with specific information of the target system. In this paper, we present an application of particle filtering for the prediction of degradation in steam generator tubes. With a case study, we also show how the prediction results vary depending on the uncertainty of the measurement data.

Mechanical Properties of MoN-Cu Coatings according to Pre-treatment of AISI H13 Tool Steel (H13 공구강의 전처리에 따른 Mo-Cu-N 코팅의 기계적 특성)

  • Park, Hyun-Jun;Moon, Kyoung-Il;Kim, Sang-Sub
    • Journal of the Korean institute of surface engineering
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    • v.53 no.6
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    • pp.343-350
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    • 2020
  • The degradation of mechanical properties of nitride coatings to steel substrates is one of the main challenges for industrial applications. In this study, plasma nitriding treatment was used in order to increase the mechanical properties of Mo-Cu-N coating to the H13 tool steel. The nanostructured Mo-Cu-N coating was deposited using pulsed DC magnetron sputtering method with a single alloy Mo-Cu target. Mechanical properties of MoN-Cu coated samples after nitriding were found to be relatively better than non-nitrided MoN-Cu coating.

Butein Disrupts Hsp90's Molecular Chaperoning Function and Exhibits Anti-proliferative Effects Against Drug-resistant Cancer Cells

  • Seo, Young Ho
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3345-3349
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    • 2013
  • Hsp90 shows great promise as a therapeutic target due to its potential to disable multiple signaling pathways simultaneously. In this study, we discovered that a natural product, butein moderately inhibited the growth of drug-resistant cancer cells (A2780cis and H1975), and brought about the degradation of oncogenic Hsp90 client proteins. The study demonstrated that butein would be a therapeutic lead to circumvent drug-resistance in cancer chemotherapy. The structure-based screening, synthesis, and biological evaluation of butein are described herein.

Effect of Feed Types on Ochratoxin A Disappearance in Goat Rumen Fluid

  • Upadhaya, Santi Devi;Yang, Liu;Seo, Ja-Kyeom;Kim, Myung-Hoo;Lee, Chang-Kyu;Lee, Chan-Ho;Ha, Jong-K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.24 no.2
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    • pp.198-205
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    • 2011
  • This study was conducted to investigate the effect of feed types on Ochratoxin A (OTA) degradation by Korean native goats. Rumen fluid from canulated goats fed whole roughage or 50% roughage served as a source of micro-organisms. Experiments were undertaken i) to investigate OTA degradation ability in a $2{\times}4$ factorial arrangement with different feed types (100% roughage vs. 50% roughage) and rumen fluid fractions (whole rumen fluid, cells, autoclaved rumen fluid and supernatant) supplemented with OTA ii) to evaluate OTA degradation by the rumen fluid of goats fed two different diets at different time points (0, 3, 6, 9 and 12 h) of feeding iii) to isolate potential rumen microorganisms and iv) to identify elements responsible for OTA degradation. Rumen fluid from goats fed 100% roughage had higher (p<0.05) OTA degradability than 50% roughage diets. OTA degradation based on rumen fluid collection times showed that rumen fluid at 0 h showed significantly higher (p<0.05) degradability. Carboxypeptidase A (CPA) enzyme has been reported to be responsible for OTA degradation. Thus, using real time PCR, primers designed to target the CPA gene from Bacillus licheniformis could be amplified using genomic DNA from rumen fluid of goats and sequenced, thus enabling evaluation of the Bacillus population under different feeding condition and times. Our findings showed that the Bacillus population was significantly higher (p<0.05) before feeding (0 h) in animals which were fed a whole roughage diet, giving indirect evidence of OTA degradation being influenced by Bacillus sps. Thus, it can be concluded that OTA degradability is influenced by feed, feeding time and Bacillus licheniformis population.