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Performance Optimization of IPN in RF PLL using Bayesian Optimization
Ji-Sub Yoon,Doing-In Choi,Seung Young Park,In-Chul Hwang 대한전자공학회 2024 Journal of semiconductor technology and science Vol.24 No.2
The performance optimization of a circuit in a short time is one of the important issues for IC testing. Traditional methods depend on domain knowledge and exhaustive search (ES) for feasible parameters. In this paper, we proposed the sub-optimal control of the integrated phase noise (IPN) characteristics of RF phase lock loop (PLL) using a Bayesian optimization. For data acquisition, we designed an autonomous measurement platform based on general purpose interface bus (GPIB) and Python. Using our algorithm, we achieved performance within around 3 dB of the optimal at the 95th percentile and reduced the search time for optimal parameters by at least 98.75% compared to the ES method.
Bayesian Optimization을 활용한 RF PLL의 IPN 특성 최적화 방안 연구
윤지섭(Ji-Sub Yoon),김정훈,황인철(In-Chul Hwang),박승영(Seungyoung Park) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11
In this paper, we proposed the sub-optimal control of the IPN characteristics of RF PLLs using Bayesian optimization. Specifically, a GPIB interface using Python and a phase noise analyzer were used to acquire the measurement data of IPN from a DUT board. From the results, we observed that the number of measurements can be reduced by 95% while achieving 94.2% of the optimal performance.
Shin, Man Sub,Park, Yoon Kook,Nam, Sung Chan,Hwang, Kwang-Jin The Chemical Society of Japan 2012 Chemistry letters Vol.41 No.2
<P>This investigation demonstrated that bicarbonate ions were selectively formed over carbamate in a CO<SUB>2</SUB> absorption process using piperidine and piperazine derivatives based on <SUP>13</SUP>C NMR. Piperidines with methyl or hydroxymethyl substituent at 2 position (PiP-Me and PiP-MeOH) and 2,5-dimethylpiperazine (DM-PiZ) generated the bicarbonate ions as main adducts in reaction with CO<SUB>2</SUB>. The absorptions of CO<SUB>2</SUB> by those aqueous amines (PiP-Me and DM-PiZ) were faster than those of MEA (2-aminoethanol).</P>
Hwang, Sun Mi,Lee, Yun Jung,Lee, Yong Pyo,Yoon, Jung Joo,Lee, So Min,Cha, Jeong Dan,Choi, Kyung Min,Kang, Dae Gill,Lee, Ho Sub Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-
<P>The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial walls is an important pathogenic factor of vascular disorders such as diabetic atherosclerosis. We have reported the anti-inflammatory effect of an aqueous extract from <I>Prunella vulgaris</I> (APV) in vascular endothelial cell. In the present study, APV exhibited inhibitory effects on high glucose-stimulated VSMC proliferation, migration, and invasion activities, inducing G<SUB>1</SUB> cell cycle arrest with downregulation of cyclins and CDKs and upregulation of the CKIs, p21<SUP>waf1/cip1</SUP> and p27<SUP>kip1</SUP>. Furthermore, APV dose dependently suppressed the high glucose-induced matrix metalloproteinase activity. High glucose-induced phosphorylation of ERK, p38 MAPK, was decreased by the pretreatment of APV. NF-<I><I>κ</I></I>B activation by high glucose was attenuated by APV, as an antioxidant. APV attenuated the high glucose-induced decrease of nuclear factor E2-related factor-2 (Nrf2) translocation and heme oxygenase-1 (HO-1) expression. Intracellular cGMP level was also increased by APV treatment. These results demonstrate that APV may inhibit VSMC proliferation via downregulating ROS/NF-<I><I>κ</I></I>B /ERK/p38 MAPK pathways. In addition, APV has a beneficial effect by the interaction of Nrf2-mediated NO/cGMP with HO-1, suggesting that <I>Prunella vulgaris</I> may be useful in preventing diabetic atherosclerosis.</P>
Hwang, Hyun Sub,Yoon, Kyoung Wan,Kim, Kwang Je,Yoon, Je Hyun,Cho, Ssang-Goo,Choi, Eui-Ju 이화여자대학교 세포신호전달연구센터 2005 고사리 세포신호전달 심포지움 Vol. No.7
We have recently reported a novel anti-apoptotic protein named CIIA(a CAD inhibitor that interacts with ASK1) that antagonizes both ASK1- and CAD-mediated processes. To further understand the function of CIIA, we searched for CIIA-interacting proteins by using a pull-down assay. This in vitro binding analysis revealed that CIIA directly interacts with son of sevenless 1(SOS1), the guanine nucleotide exchange factor(GEF) of Ras. Furthermore, endogenous Ciia physically associated with endogenous SOS1 in intact cells, and this interaction was enhanced after cells were exposed to epidermal growth factor(EGF). Overexpressed CIIA blocked EGF-induced Ras activation, thereby inhibiting the EGF-initiated stimulation of the ERK pathway. CIIA, by binding to the Ras interacting domain of SOS1, interfered with the interaction between SOS1 and Ras. Finally, CIIA suppressed the EGF-induced stimulation of DNA synthesis in MDCK cells. Taken together, these results suggest that CIIA functions as a negative regulator of the EGFR-Grb2-SOS-Ras signaling events.
CIIA functions as a molecular switch for the Rac1-specific GEF activity of SOS1
Hwang, Hyun Sub,Hwang, Sang Gil,Cho, Jun-Ho,Chae, Ji Soo,Yoon, Kyoung Wan,Cho, Ssang-Goo,Choi, Eui-Ju Rockefeller University Press 2011 The Journal of cell biology Vol.195 No.3
<▼1><P>CIIA mediates the TGF-β–induced activation of SOS1–Rac1 signaling and cell migration.</P></▼1><▼2><P>Son of sevenless 1 (SOS1) is a dual guanine nucleotide exchange factor (GEF) that activates the guanosine triphosphatases Rac1 and Ras, which mediate signaling initiated by peptide growth factors. In this paper, we show that CIIA is a new binding partner of SOS1. CIIA promoted the SOS1–Rac1 interaction and inhibited the SOS1–Ras interaction. Furthermore, CIIA promoted the formation of an SOS1–EPS8 complex and SOS1-mediated Rac1 activation, whereas it inhibited SOS1-mediated activation of Ras. Transforming growth factor β (TGF-β) up-regulated the expression of CIIA and thereby promoted the association between CIIA and SOS1 in A549 human lung adenocarcinoma cells. Depletion of CIIA in these cells by ribonucleic acid interference inhibited the TGF-β–induced interaction between SOS1 and EPS8, activation of Rac1, and cell migration. Together, these results suggest that CIIA mediates the TGF-β–induced activation of SOS1–Rac1 signaling and cell migration in A549 cells. They further show that CIIA functions as a molecular switch for the GEF activity of SOS1, directing this activity toward Rac1.</P></▼2>
Hwang, Hyun Sub,Hwang, Sang Gil,Yoon, Kyoung-Wan,Yoon, Je-Hyun,Roh, Kyung-Hye,Choi, Eui-Ju The Company of Biologists Limited 2014 Journal of cell science Vol.127 No.8
<P>Son of sevenless 1 (SOS1) is a Ras-specific guanine-nucleotide-exchange factor (GEF) that mediates intracellular signaling processes induced by receptor tyrosine kinases. In this study, we show that CIIA (also known as VPS28) physically associates with SOS1 and thereby inhibits the GEF activity of SOS1 on Ras, which prevents the epidermal growth factor (EGF)-induced activation of the Ras–Erk1/2 pathway. Furthermore, CIIA inhibited cyclin D1 expression, as well as DNA, synthesis in response to EGF. Intriguingly, CIIA failed to inhibit the Ras-specific GEF activity of Noonan-syndrome-associated SOS1 mutants (M269R, R552G, W729L and E846K). Taken together, our results suggest that CIIA functions as a negative modulator of the SOS1–Ras signaling events initiated by peptide growth factors including EGF.</P>
NaF-FeF2 nanocomposite: New type of Na-ion battery cathode material
Hwang, Insang,Jung, Sung-Kyun,Jeong, Eun-Suk,Kim, Hyunchul,Cho, Sung-Pyo,Ku, Kyojin,Kim, Hyungsub,Yoon, Won-Sub,Kang, Kisuk Springer-Verlag 2017 NANO RESEARCH Vol.10 No.12
<P>Na-ion batteries (NIBs) are considered one of the most attractive alternatives for Li-ion batteries (LIBs) because of the natural abundance of Na and the similarities between the NIB technology and the well-established LIB technology. However, the discovery of high-performance electrode materials remains a key factor in the success of NIBs. Herein, we propose a new type of cathode material for NIBs based on a nanocomposite of an alkali metal fluoride (NaF) and a transition metal fluoride (FeF2). Although neither of these components is electrochemically active with Na, the nanoscale mixture of the two can deliver a reversible capacity of similar to 125 mAh/g in the voltage range of 1.2-4.8 V vs. Na/Na+ via an Fe2+/Fe3+ redox couple. X-ray absorption spectroscopy reveals that the reversible Na storage is aided by the F-ions due to the decomposition of NaF, which are absorbed on the surface of FeF2, promoting the redox reaction of Fe and triggering the gradual transformation of the mother structure (FeF2) into a new (FeF3-like) host structure for the Na ions. This unique Na-ion storage phenomenon, which is reported for the first time, will introduce an avenue for designing novel cathode materials for NIBs.</P>
<i>Prunella vulgaris</i> Suppresses HG-Induced Vascular Inflammation via Nrf2/HO-1/eNOS Activation
Hwang, Sun Mi,Lee, Yun Jung,Yoon, Jung Joo,Lee, So Min,Kim, Jin Sook,Kang, Dae Gill,Lee, Ho Sub Molecular Diversity Preservation International (MD 2012 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.13 No.1
<P>Vascular inflammation is an important factor which can promote diabetic complications. In this study, the inhibitory effects of aqueous extract from <I>Prunella vulgaris</I> (APV) on high glucose (HG)-induced expression of cell adhesion molecules in human umbilical vein endothelial cells (HUVEC) are reported. APV decreased HG-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. APV also dose-dependently inhibited HG-induced adhesion of HL-60 monocytic cells. APV suppressed p65 NF-κB activation in HG-treated cells. APV significantly inhibited the formation of intracellular reactive oxygen species (ROS). HG-stimulated HUVEC secreted gelatinases, however, APV inhibited it. APV induced Akt phosphorylation as well as activation of heme oxygenase-1 (HO-1), eNOS, and nuclear factor E2-related factor 2 (Nrf2), which may protect vascular inflammation caused by HG. In conclusion, APV exerts anti-inflammatory effect via inhibition of ROS/NF-κB pathway by inducing HO-1 and eNOS expression mediated by Nrf2, thereby suggesting that <I>Prunella vulgaris</I> may be a possible therapeutic approach to the inhibition of diabetic vascular diseases.</P>