Bactericidal effect through non-uptake pathway with photofunctional silicon polymer that generates reactive oxygen species

Wang, K.K.,Jung, S.J.,Hwang, J.W.,Kim, B.J.,Kim, D.H.,Bae, I.K.,Jeong, S.H.,Kim, Y.R. Elsevier Sequoia 2016 Journal of photochemistry and photobiology Chemist Vol.315 No.-

<P>We report bactericidal effect of photosensitizer (H2TPP: 5,10,15,20-tetraphenyl-21H,23H-porphyrin) through non-uptake pathway and efficacy of the photofunctional silicon polymer to the decomposition of the formed biofilm and the suppression of the biofilm formation. The photoftmctional silicon polymer (PSP), which is the silicon polymer embedded with a photosensitizer, is fabricated by a simple solvent swell-encapsulation-shrink method. Reactive oxygen generation from PSP was confirmed by using the decomposition reaction of 1,3-diphnyl-isobenzofuran (DPBF). Also, singlet oxygen generation which is one of the reactive oxygen species (ROS) from PSP is directly confirmed with time and wavelength resolved singlet oxygen phosphorescence spectroscopy. For the influence study of ROS under the non-uptake condition of photosensitizer (PS to bacteria), photodynamic inactivation (PDI) effect of PSP is evaluated for Gram-positive, Gram-negative bacteria, and fungi. Those microorganisms were inactivated by PSP within 1 h under the given power of laser light (63.7 mW/cm(2)). Among the bacteria, especially, Staphylococcus aureus as the Gram-positive bacteria were completely disinfected under the given experimental condition. Furthermore, PSP successfully demonstrates the decomposition of the formed biofilm and the suppression of the biofilm formation with green light emitting diode (GLED, 3.5 mW/cm(2),lambda(max) = 517 nm, FWHM = 37 nm), which shows the practical application possibility of bactericidal material. (C) 2015 Elsevier B.V. All rights reserved.</P>

In vivo imaging of tumor apoptosis using histone H1-targeting peptide

Wang, K.,Purushotham, S.,Lee, J.Y.,Na, M.H.,Park, H.,Oh, S.J.,Park, R.W.,Park, J.Y.,Lee, E.,Cho, B.C.,Song, M.N.,Baek, M.C.,Kwak, W.,Yoo, J.,Hoffman, A.S.,Oh, Y.K.,Kim, I.S.,Lee, B.H. Elsevier Science Publishers 2010 Journal of controlled release Vol.148 No.3

In vivo imaging of apoptosis could allow monitoring of tumor response to cancer treatments such as chemotherapy. Using phage display, we identified the CQRPPR peptide, named ApoPep-1(Apoptosis-targeting Peptide-1), that was able to home to apoptotic and necrotic cells in tumor tissue. ApoPep-1 also bound to apoptotic and necrotic cells in culture, while only little binding to live cells was observed. Its binding to apoptotic cells was not dependent on calcium ion and not competed by annexin V. The receptor for ApoPep-1 was identified to be histone H1 that was exposed on the surface of apoptotic cells. In necrotic cells, ApoPep-1 entered the cells and bound to histone H1 in the nucleus. The imaging signals produced during monitoring of tumor apoptosis in response to chemotherapy was enhanced by the homing of a fluorescent dye- or radioisotope-labeled ApoPep-1 to tumor treated with anti-cancer drugs, whereas its uptake of the liver and lung was minimal. These results suggest that ApoPep-1 holds great promise as a probe for in vivo imaging of apoptosis, while histone H1 is a unique molecular signature for this purpose.

Overview of KSTAR research progress and future plans toward ITER and K-DEMO

Park, H.K.,Choi, M.J.,Hong, S.H.,In, Y.,Jeon, Y.M.,Ko, J.S.,Ko, W.H.,Kwak, J.G.,Kwon, J.M.,Lee, J.,Lee, J.H.,Lee, W.,Nam, Y.B.,Oh, Y.K.,Park, B.H.,Park, J.K.,Park, Y.S.,Wang, S.J.,Yoo, M.,Yoon, S.W.,B IOP 2019 Nuclear fusion Vol.59 No.11

<P>A decade-long operation of the Korean Superconducting Tokamak Advanced Research (KSTAR) has contributed significantly to the operation of superconducting tokamak devices and the advancement of tokamak physics which will be beneficial for the ITER and K-DEMO programs. Even with limited heating capability, various conventional as well as new operating regimes have been explored and have achieved improved performance. As examples, a long pulse high-confinement mode operation with and without an edge-localized mode (ELM) crash was well over 70 and 30 s, respectively. The unique capabilities of KSTAR allowed it to improve the capability of controlling harmful instabilities, and they have been instrumental in uncovering much new physics. The highlights are that the L/H transition threshold power is sensitive to the resonant magnetic perturbation (RMP) and insensitive to non-resonant magnetic perturbation. Co-<I>I</I> <SUB>p</SUB> offset rotation dominated by an electron channel predicted by general neoclassical toroidal viscosity theory was confirmed. Improved heat dispersal in a divertor system using three rows of rotating RMP was demonstrated and predictive control of the ELM-crash with <I>a priori</I> modeling was successfully tested. In magnetohydrodynamic physics, validation of the full reconnection model (i.e. <I>q</I> <SUB>0</SUB>  >  1 right after the sawtooth crash) and self-consistent validation of the anisotropic distribution of turbulence amplitude and flow in the presence of the 2/1 island with theoretical models were achieved. The turbulence amplitude induced by RMP was linearly increased with the slow RMP coil current ramp-up time (i.e. the magnetic diffusion time scale). The <I>D</I> <SUB> <I>α</I> </SUB> spikes (i.e. ELM-crash amplitude) was linearly decreased with the turbulence amplitude and not correlated with the perpendicular electron flow. In the turbulence area, a non-diffusive ‘avalanche’ transport event and the role of a quiescent coherent mode in confinement were studied. To accommodate the anticipation of a higher performance of the KSTAR plasmas with the increased heating powers, a new divertor/internal interface with a full active cooling system will be implemented after a full test of the new heating (neutral beam injection II and electron cyclotron heating) and current drive (CD) (Helicon and lower hybrid CD) systems. An upgrade plan for the internal hardware, heating systems and efficient CD system may allow for a long pulse operation of higher performance plasmas at <I>β</I> <SUB>N</SUB>  >  3.0 with <I>f</I> <SUB>bs</SUB> ~ 0.5 and <I>T</I> <SUB>i</SUB>  >  10 keV.</P>

레이저 쇼크 피닝에 의한 H13/Cu 경사기능재료의 잔류응력 평가

신기훈(K. H. Shin),정호연(H. R. Cheong),정성균(S. K. Cheong),최대철(D. C. Choi),왕환(H. Wang) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

경사기능재료(Functionally Graded Materials)는 소재의 물성이 점진적으로 변화하는 것이 특징으로, 각 소재의 장점을 극대화 하는 것이 가능하여 많은 공학 분야에 적용될 수 있다. 본 연구에서는 DMT (Laser-aided Direct Metal Tooling) 공정을 통해 열전도성 사출 금형의 형상적응형 냉각회로 등에 적용 가능한 H13/Cu FGM 시편을 제작하였다. 레이저 기반 금속 프린팅으로 소재를 적층할 경우, 발생되는 열에 의해 제작된 시편의 균열 등을 유발하는 인장 잔류응력의 형성이 필연적이다. 따라서 본 연구에서는 적층 시편의 표면에 형성되는 인장잔류응력을 해소할 수 있는 방안으로 LSP (Laser Shock Peening) 공정 연구를 수행하였다. H13, Cu 소재의 무게 분율 20 wt%에 의해 6 종의 H13/Cu FGM 시편을 먼저 적층 제작하고, LSP 공정 전후의 시편에서 XRD 회절 패턴 분석(2θ 각도 변화 분석)을 통해 잔류응력을 측정하였다. 실험결과 LSP 공정 후 소재의 표면에 생성되는 압축잔류응력은 소재의 미세조직을 변형시키며, DMT 공정으로 생성된 인장잔류응력을 효과적으로 상쇄 시키는 것으로 판단된다.

Fermentation for Liquid-type Yogurt with Lactobacillus casei 911LC

Ko, I.H.,Wang, M.K.,Jeon, B.J.,Kwak, H.S. Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.1

This study was carried out to find the attributes for liquid-type yogurt with Lactobacillus casei 911LC during 72 h fermentation at $37^{\circ}C$. The pH decreased up to 32 h and plauteaued thereafter, and the titratable acidity increased up to 40 h. The growth of lactic acid bacteria sharply increased with $3.5{\times}10^7$ cfu/ml up to 40 h of fermentation and slowly decreased thereafter. The free amino acids produced during fermentation reached the maximum value at 44 h and gradually decreased thereafter. Bitterness sensory scores were the highest at 44 h of fermentation. In the result of electrophoresis, the band mostly disappeared at 72 h fermentation. The present data showed that the range of optimum fermentation time for liquid-type yogurt using Lactobacillus casei 911LC was from 40 to 44 h.

Dielectric and piezoelectric properties of Li-substituted lead-free (Bi_0.5Na_0.5)TiO₃@?(Bi_0.5K_0.5)TiO₃@?BaTiO₃ ceramics

Wang, L.,Song, T.K.,Lee, S.C.,Cho, J.H.,Sung, Y.S.,Kim, M.H.,Choi, K.S. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.4

Lead-free 0.79(Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>)TiO<SUB>3</SUB>-0.14[Bi<SUB>0.5</SUB>(K<SUB>0.5-x</SUB>Li<SUB>x</SUB>)]TiO<SUB>3</SUB>-0.07BaTiO<SUB>3</SUB> (BNBK79+xLi, x=0.0, 0.1, 0.2, 0.25, 0.3, and 0.4) ceramics were prepared by conventional solid state reaction process. The crystalline structures and surface morphologies are investigated by X-ray diffraction method and scanning electron microscopy. Dielectric and piezoelectric properties were measured. With increasing of lithium substitution, the Curie temperatures of BNBK79+xLi ceramics increase, but the maximum value of the dielectric constant decreases. And a relatively large remnant polarization of 17.6μC/cm<SUP>2</SUP> and 157pC/N of d<SUB>33</SUB> has been obtained when x=0.3.

A Case of Multiple Cutaneous Leiomyoma

Kang, H. J 大韓皮膚科學會 1996 대한피부과학회지 Vol.34 No.4

Analysis of the Inhibition Layer of Galvanized Dual-Phase Steels

( K K Wang ),( H P Wang ),( L Chang ),( D Can ),( T R Chen ),( H B Chen ) 한국부식방식학회(구 한국부식학회) 2012 Corrosion Science and Technology Vol.11 No.1

The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This study presents a characterization result on the inhibition layer fomed on C-Mn-Cr and C-Mn-Si dual-phase steels after a short time galvanizing. The samples were annealed at 800˚C for 60 s in N2-l0% H2 atmosphere with a dew point of -30˚C, and were then galvanized in a bath containing 0.2%Al. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) was employed for characterization. The TEM electron diffraction shows that only Fe2Als intermetallic phase was formed. No orientation relationship between the Fe2Al5 phase and the steel substrate could be identified. Two peaks of Al 2p photoelectrons, one from metallic aluminum and the other from Al3+ ions, were detected in the inhibition layer, indicating that the layer is in fact a mixture of Fe2Al5 and A12O3. TEM/EDS analysis verifies the existence of A12O3 in the boundaries of Fe2Al5 grains. The nucleation of FeAl5 and the reduction of the surface oxide probably proceeded concurrently on galvanizing, and the residual oxides prohibited the heteroepitaxial growth of Fe2Al5.

Characterization and Formation Mechanism of Ni3Si–Al2O3 Nanocomposite Prepared by Mechanochemical Reduction Method

H. Chen,D. M. Zhou,L. Cai,Y. Y. Wang,K. Yu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

In this present work, Ni3Si–Al2O3 nanocomposite powders were synthesized by mechanical milling using NiO, Si and Alas raw materials. The phase transformation, formation mechanism and microstructure evolution of the powders duringmechanical milling were investigated by X-ray difraction (XRD), diferential thermal analysis (DTA), scanning electronmicroscopy (SEM), transition electron microscopy (TEM) and microhardness measurements. Results showed that the Ni3Si,Al2O3 and Ni31Si12 phases formed after 5 h of milling with a rapid mechanically induced self-propagating synthesis mode. The average grain size and internal strain of Ni3Si and Al2O3 after 30 h of milling were (16.8 nm, 1.27%) and (19.6 nm,0.94%), respectively. The maximum microhardness value of 813 HV was obtained in the 30 h milled powder. The relationship between the hardness and grain size of the powders satisfes the Hall–Petch relationship. Ni3Si–Al2O3 nanocompositepowders are very stable during heating at 950 °C. By annealing of the milled powders leads to grain growth, internal strainand microhardness of Ni3Si powder decrease and transformation of disordered structure to an ordered state. A long-rangeordering parameter (LRO) of 0.97 for the ordered Ni3Si can be achieved after annealing at 950 °C for 2 h.

Effect of Monensin and Fish Oil Supplementation on Biohydrogenation and CLA Production by Rumen Bacteria In vitro When Incubated with Safflower Oil

Wang, J.H.,Choi, S.H.,Yan, C.G.,Song, M.K. Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.2

An in vitro study was conducted to examine the effect of monensin or fish oil addition on bio-hydrogenation of $C_{18^-} unsaturated fatty acids and CLA production by mixed ruminal bacteria when incubated with safflower oil. Commercially manufactured concentrate (1%, w/v) with safflower oil (0.2%, w/v) were added to mixed solution (600 ml) of strained rumen fluid and McDougalls artificial saliva (control). Monensin $Rumensin^{(R)}$, 10 ppm, w/v, MO), mixed fish oil (0.02%, w/v, absorbed to 0.2 g alfalfa hay, FO) or similar amounts of monensin and fish oil (MO+FO) to MO and FO was also added into the control solution. All the culture solutions prepared were incubated in the culture jar anaerobically at $39^{\circ}C$ up to 12 h. Higher pH (p<0.047) and ammonia concentration (p<0.042) were observed from the culture solution containing MO at 12 h incubation than those from the culture solutions of control or FO. The MO supplementation increased (p<0.0001-0.007) propionate proportion of culture solution but reduced butyrate proportion at 6 h (p<0.018) and 12 h (p<0.001) of incubations. Supplementation of MO or MO+FO increased (p<0.001) the proportions of $C_{18:2}$. The MO alone reduced (p<0.022-0.025) the proportion of c9,t11-CLA compared to FO in all incubation times. The FO supplementation increased the proportion of c9,t11-CLA. An additive effect of MO to FO in the production of c9,t11-CLA was observed at 6 h incubation. In vitro supplementation of monensin reduced hydrogenation of $C_{18^-}$UFAs while fish oil supplementation increased the production of CLA.