Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)

Lim, H.W.,Lee, H.W.,Cho, H.S.,Je, U.K.,Park, C.K.,Kim, K.S.,Kim, G.A.,Park, S.Y.,Lee, D.Y.,Park, Y.O.,Woo, T.H.,Lee, S.H.,Chung, W.H.,Kim, J.W.,Kim, J.G. Elsevier BV * North-Holland 2017 Nuclear Instruments & Methods in Physics Research. Vol. No.

<P><B>Abstract</B></P> <P>Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> It is proposed for the single grid-based phase-contrast x-ray imaging (g-PCXI) technique. </LI> <LI> We implemented for a numerical simulation code. </LI> <LI> The preliminary experiment with several samples to compare is performed. </LI> <LI> It is expected to be useful to design an optimal g-PCXI system. </LI> </UL> </P>

Five-year clinical outcomes in patients with significant coronary artery spasm: A propensity score-matched analysis

Choi, B.G.,Park, S.H.,Rha, S.W.,Park, J.Y.,Choi, S.Y.,Park, Y.,Xu, S.,Ngow, H.A.,Ali, J.,Li, H.,Kim, J.B.,Lee, S.,Na, J.O.,Choi, C.U.,Lim, H.E.,Kim, J.W.,Kim, E.J.,Park, C.G.,Seo, H.S.,Oh, D.J. Elsevier/North-Holland Biomedical Press 2015 INTERNATIONAL JOURNAL OF CARDIOLOGY Vol.184 No.-

Background: Coronary artery spasm (CAS) is known to be a risk factor of acute coronary syndrome and angina pectoris. However, there is no currently available data with larger study population regarding long-term clinical outcomes of CAS in real world clinical practice. Objectives: We evaluated the prevalence of CAS and the impact of CAS on 5-year clinical outcomes in a series of Asian CAS patients documented by intracoronary acetylcholine (Ach) provocation test. Methods: A total of 1413 consecutive patients without significant coronary artery disease (CAD) who underwent Ach provocation test between Nov. 2004 and Oct. 2008 were enrolled. Significant CAS was defined as >70% of narrowing by incremental intracoronary injection of 20, 50 and 100μg. Patients were divided into two groups based on the presence of significant CAS (the non-CAS group: n=640, the CAS group; n=773). To adjust potential confounders, a propensity score matched (PSM) analysis was performed using the logistic regression model. Results: A total of 54.7% (773/1413) patients were diagnosed as CAS documented by Ach provocation test. After PSM analysis, 2 propensity-matched groups (451 pairs, n=902, C-statistic=0.677) were generated. Despite of similar incidence of individual hard endpoints including mortality, myocardial infarction and revascularization, the CAS group showed the higher trend of recurrent angina requiring follow up angiography than the non-CAS group up to 5years (HR; 1.56, 95% C.I.; 0.99-2.46, p=0.054). Conclusions: The prevalence of CAS was 54.7%. Although the cumulative incidence of recurrent angina requiring follow up coronary angiography seems to be increased up to 5years in CAS patients, CAS patients was not associated with major individual and composite clinical outcomes such as mortality, MI, PCI, CVA with optimal medical therapy as compared with patients without CAS.

Quantifying herbicide dose-response and resistance in <i>Echinochloa</i> spp. by measuring root length in growth pouches

Zhang, C. J.,Lim, S. H.,Kim, J. W.,Song, J. S.,Yook, M. J.,Nah, G.,Valverde, B. E.,Kim, D. S. Canadian Science Publishing 2015 Canadian journal of plant science. Revue canadienn Vol.95 No.6

<P> Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose-response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181-1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose-response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose-responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose-response model and similar to those estimated by a whole-plant assay. Accurate dose-response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180-300 mg a.i. L<SUP>−1</SUP> and 80-120 mg a.i. L<SUP>−1</SUP> for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350-500 mg a.i. L<SUP>−1</SUP> for barnyardgrass and 650-1000 mg a.i. L<SUP>−1</SUP> for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose-response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays. </P>

The enhancement of electrical and optical properties of PEDOT:PSS using one-step dynamic etching for flexible application

Lim, K.,Jung, S.,Lee, S.,Heo, J.,Park, J.,Kang, J.W.,Kang, Y.C.,Kim, D.G. Elsevier Science 2014 Organic Electronics Vol.15 No.8

The conductivity enhancement of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by dynamic etching process was investigated to introduce the outstanding and simplest method for soft electronics. Four different samples which were pristine PEDOT:PSS, PEDOT:PSS doped with 5wt.% DMSO, PEDOT:PSS with dipping process, and PEDOT:PSS with dynamic etching process were prepared to compare the properties such as conductivity, morphology, relative atomic percentage, and topography. All samples were characterized by four point probe, current atomic force microscopy (C-AFM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. The conductivity of the sample with dynamic etching process showed the highest value as 1299S/cm among four samples. We proved that the dynamic etching process is superior to remove PSS phase from PEDOT:PSS film, to flow strong current through entire surface of PEDOT:PSS, and to show the smoothest surface (RMS 2.28nm). XPS analysis was conducted for accurate chemical and structural surface environments of four samples and the relative atomic percentage of PEDOT in the sample with dynamic etching was the highest as 29.5%. The device performance of the sample with the dynamic etching process was outstanding as 10.31mA/cm<SUP>2</SUP> of J<SUB>sc</SUB>, 0.75eV of V<SUB>oc</SUB>, 0.46 of FF, and 3.53% of PCE. All properties and the device performance for PEDOT:PSS film by dynamic etching process were the most excellent among the samples.

한우 경제형질에 미치는 Mitochondrial DNA D-loop 영역의 염기서열 변이효과

오재돈,윤두학,공홍식,임현진,이학교,조병욱,홍기창,전광주 한국동물자원과학회 2003 한국축산학회지 Vol.45 No.6

This study was performed to analyse the sequences of variations of mtDNA D-loop and their effects on carcass traits in Hnawoo(Korean cattle). The resulting sequences were compared with perviously published sequences for other cattle breeds(GenBank J01394). The PCR was used to amplify a total of 964 bp between nucleotide 15758 and 383 within D-loop region of mtDNA using specific primers. Twenty five polymorphic sites by nucleotide substitution were found in mtDNA of Hanwoo. The frequencies of positions at 169, 16042, 16093. 16119, 16255 and 16302 nt with high levels of sequence polymorphism were 0.891, 0.117, 0.109, 0.182, 0.197 and 0.117, respectively. The substitution effect at 169 and 16119 nt was found significant on marbling score. Also substitution effect at 169 and 16042 nt was highly significant(p<0.01) on backfat, thickness. Polymorphisrn of mtDNA sequence in D-loop region could be useful for the analysis of cytoplasmic genetic variation and associations with the other economically important traits and maternal lineage analysis in Hanwoo.

완효성 비료 분시별 세물차의 수량 및 품질

박장현(JㆍHㆍPark),신기호(KㆍHㆍShin),최 정(JㆍChoi),한재석(JㆍSㆍHan),임근철(GㆍCㆍLim) 한국차학회 2002 한국차학회지 Vol.8 No.2

A field experiment was conducted to evaluate effect by split-application method of slow-release fertilizer on the tea plant. The yield of the 1st harvested tea leaves had increased 3% in the slow-release fertilizer(two time split manuring) compared with the traditional manuring(four time split manuring), and that of the slow-release fertilizer to one time split manuring was decreased 14±3%. In case of the 1st harvested leave, the contents of chemical components related to quality such as total nitrogen, total amino acid, caffeine, chlorophyll, vitamin C, fatty acid and theanine were somewhat higher in the slow-release fertilizer(two time split manuring) than those of the traditional manuring, but that of tannin was low. The one time split manuring of slow-release fertilizer had a contrary tendency with two time split manuring treatment. In scoring test, appearance and quality of green tea were more excellence in the two time split maunring compared with one time split manuring of slow-release fertilizer and with the traditional manuring (four time split manuring). Yield of tea was increased, quality of tea was improved and loss of N, P, K was decreased with use of slow-release fertilizer.

Pb(Zr, Ti)O₃ 강유전체 박막의 스퍼터링 증착과 후속열처리

장지근(G. K. Chang),박재영(J. Y. Park),윤진모(J. M. Yoon),임성규(S. K. Lim),장호정(H. J. Chang) 한국진공학회(ASCT) 1997 Applied Science and Convergence Technology Vol.6 No.1

Pt/Ti/SiO₂/Si 기판상에 고주파 마그네트론 스퍼터링 방식으로 PZT 박막 [두께: 3000Å]을 증착하고 RTA 방식으로 후속 열처리[열처리온도: 550℃~650℃, 열처리 시간: 10초~50초]를 실시하여 직경 0.2㎜ 소자의 FECAPs(ferroelectric capacitors)를 제작하였다. 제작된 커패시터의 유전상수(ε_r)와 잔류분극(2P_r)은 650℃로 30초간 열처리한 시편에서 ε_r(1kHz) = 690, 2Pr(-5V~5V sweep) = 22 μC/㎠로 가장 높게 나타났으며 유전 정접(tan δ)과 누설전류(J_ㅣ)는 600℃에서 30 초간 열처리한 시편에서 tan δ(≥ 10kHz)≤0.02, J_l(5V)=3 μA/㎠로 가장 낮게 나타났다. FECAPS(ferroelectric capacitors) have been fabricated by RF magnetron sputtering deposition of 3000Å PZT thin films on the Pt/Ti/SiO₂/Si substrates and post-annealing with the temperature of 550℃~650℃ for 10 sec ~50 sec in a RTA system. The electrical characteristics of the fabricated capacitors showed the highest dielectric constant and remanent polarization[ε_r(1kHz) = 690, 2P_r(-5V~5V sweep) = 22 μC/㎠] in the samples annealed at 650℃ for 30 sec, while the lowest tangent loss and leakage current[tan δ(≥10kHz)≤0.02, J_l/5V) = 3 μA/㎠] in the samples annealed at 600℃ for 30 sec.

HIV 감염진단 표준화를 위한 정도관리(Quality Assurance) 프로그램 개발

이주실,박근용,김성순,강춘,김옥진,서순덕,박혜경,최병선,남정구,도경미,구본기,김현숙,임종백,조권,황유성,황병갑,이용래 국립보건연구원 1999 국립보건원보 Vol.36 No.-

A Prospective, Randomized, 6-Month Comparison of the Coronary Vasomotor Response Associated With a Zotarolimus- Versus a Sirolimus-Eluting Stent

Kim, J.W.,Seo, H.S.,Park, J.H.,Na, J.O.,Choi, C.U.,Lim, H.E.,Kim, E.J.,Rha, S.W.,Park, C.G.,Oh, D.J. Elsevier Biomedical 2009 JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY - Vol.53 No.18

Objectives: We prospectively compared coronary endothelial dysfunction in patients with zotarolimus-eluting stent (ZES) versus sirolimus-eluting stent (SES) implantation at 6-month follow-up. Background: A ZES has been associated with uniform and rapid healing of the endothelium. Methods: Fifty patients were randomly treated with intravascular ultrasound-guided stenting with a single stent to the mid-segment of the left anterior descending artery (20 ZES, 20 SES, and 10 bare-metal stents), and endothelial function was estimated before and after intervention at 6-month follow-up by incremental acetylcholine (Ach) (10, 20, 50, and 100 μg/min) and nitrate (200 μg/min) infusions into the left coronary ostium. The vascular response was quantitatively measured in the 5-mm segments proximal and distal to the stent. Results: In the drug-eluting stent groups, more intense vasoconstriction to incremental doses of Ach was observed at 6-month follow-up compared with the responses before stenting. Endothelial function associated with the ZES was more preserved at 6-month follow-up compared with the SES. Vasoconstriction to Ach was more prominent in the distal segments than the proximal segments in both the ZES and SES groups. Endothelium-independent vasodilation to nitrate did not differ significantly among the study groups. Conclusions: Vasoconstriction in response to Ach in the peri-stent region was less pronounced in the ZES group than the SES group at 6-month follow-up, which suggests that endothelial function associated with ZES can be more preserved than the SES.

Coherent phonons in carbon nanotubes and graphene

Kim, J.H.,Nugraha, A.R.T.,Booshehri, L.G.,Haroz, E.H.,Sato, K.,Sanders, G.D.,Yee, K.J.,Lim, Y.S.,Stanton, C.J.,Saito, R.,Kono, J. Elsevier Science Publishers [etc.] 2013 Chemical physics Vol.413 No.-

We review recent studies of coherent phonons (CPs) corresponding to the radial breathing mode (RBM) and G-mode in single-wall carbon nanotubes (SWCNTs) and graphene. Because of the bandgap-diameter relationship, RBM-CPs cause bandgap oscillations in SWCNTs, modulating interband transitions at terahertz frequencies. Interband resonances enhance CP signals, allowing for chirality determination. Using pulse shaping, one can selectively excite specific-chirality SWCNTs within an ensemble. G-mode CPs exhibit temperature-dependent dephasing via interaction with RBM phonons. Our microscopic theory derives a driven oscillator equation with a density-dependent driving term, which correctly predicts CP trends within and between (2n+m) families. We also find that the diameter can initially increase or decrease. Finally, we theoretically study the radial breathing like mode in graphene nanoribbons. For excitation near the absorption edge, the driving term is much larger for zigzag nanoribbons. We also explain how the armchair nanoribbon width changes in response to laser excitation.