Bioconversion of ginsenosides Rb₁, Rb₂, Rc and Rd by novel β-glucosidase hydrolyzing outer 3-O glycoside from Sphingomonas sp. 2F2: Cloning, expression, and enzyme characterization

Wang, L.,Liu, Q.M.,Sung, B.H.,An, D.S.,Lee, H.G.,Kim, S.G.,Kim, S.C.,Lee, S.T.,Im, W.T. Elsevier Science Publishers 2011 Journal of biotechnology Vol.156 No.2

A new β-glucosidase gene (bglSp) was cloned from the ginsenoside converting Sphingomonas sp. strain 2F2 isolated from the ginseng cultivating filed. The bglSp consisted of 1344bp (447 amino acid residues) with a predicted molecular mass of 49,399Da. A BLAST search using the bglSp sequence revealed significant homology to that of glycoside hydrolase superfamily 1. This enzyme was overexpressed in Escherichia coli BL21 (DE3) using a pET21-MBP (TEV) vector system. Overexpressed recombinant enzymes which could convert the ginsenosides Rb<SUB>1</SUB>, Rb<SUB>2</SUB>, Rc and Rd to the more pharmacological active rare ginsenosides gypenoside XVII, ginsenoside C-O, ginsenoside C-Mc<SUB>1</SUB> and ginsenoside F<SUB>2</SUB>, respectively, were purified by two steps with Amylose-affinity and DEAE-Cellulose chromatography and characterized. The kinetic parameters for β-glucosidase showed the apparent K<SUB>m</SUB> and V<SUB>max</SUB> values of 2.9+/-0.3mM and 515.4+/-38.3μmolmin<SUP>-1</SUP>mg of protein<SUP>-1</SUP> against p-nitrophenyl-β-d-glucopyranoside. The enzyme could hydrolyze the outer C3 glucose moieties of ginsenosides Rb<SUB>1</SUB>, Rb<SUB>2</SUB>, Rc and Rd into the rare ginsenosides Gyp XVII, C-O, C-Mc<SUB>1</SUB> and F<SUB>2</SUB> quickly at optimal conditions of pH 5.0 and 37<SUP>o</SUP>C. A little ginsenoside F<SUB>2</SUB> production from ginsenosides Gyp XVII, C-O, and C-Mc<SUB>1</SUB> was observed for the lengthy enzyme reaction caused by the side ability of the enzyme.

In-situ high-energy synchrotron X-ray diffraction study of micromechanical behavior of multiple phases in Ni₄₇Ti₄₄Nb₉ shape memory alloy

Sun, G.A.,Wang, X.L.,Wang, Y.D.,Woo, W.C.,Wang, H.,Liu, X.P.,Chen, B.,Fu, Y.Q.,Sheng, L.S.,Ren, Y. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.560 No.-

High-energy synchrotron X-ray diffraction technique was used to in-situ characterize microstructure, lattice strain, and phase transition behavior of a Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> shape memory alloy. Phase transformation kinetics and deformation mechanisms were studied under a uniaxial tension at three testing temperatures, i.e., -70<SUP>o</SUP>C, 25<SUP>o</SUP>C, and 150<SUP>o</SUP>C. At a testing temperature of -70<SUP>o</SUP>C, a complicated phase transformation with four stages of micromechanical deformation was identified which is associated with changes of martensite substructures. At room temperature of 25<SUP>o</SUP>C, there was no stress-induced selection process of variants of B19' phases observed. Whereas at a testing temperature of 150<SUP>o</SUP>C, there was no any phase transformation observed. It is verified that β-Nb phase, an effective stabilizer for the austenite, delays the process of martensitic transformation and relaxes the strain energy without strengthening the matrix. This new finding is important to understand the relationship between the micromechanical deformation behavior and phase transformations in the Ni<SUB>47</SUB>Ti<SUB>44</SUB>Nb<SUB>9</SUB> SMA.

Variable number of tandem repeats of 9 Plasmodium vivax genes among Southeast Asian isolates

Wang, B.,Nyunt, M.H.,Yun, S.G.,Lu, F.,Cheng, Y.,Han, J.H.,Ha, K.S.,Park, W.S.,Hong, S.H.,Lim, C.S.,Cao, J.,Sattabongkot, J.,Kyaw, M.P.,Cui, L.,Han, E.T. Verlag fur Recht und Gesellschaft 2017 Acta tropica Vol.170 No.-

<P>The variable number of tandem repeats (VNTRs) provides valuable information about both the functional and evolutionary aspects of genetic diversity. Comparative analysis of 3 Plasmodium falciparum genomes has shown that more than 9% of its open reading frames (ORFs) harbor VNTRs. Although microsatellites and VNTR genes of P. vivax were reported, the VNTR polymorphism of genes has not been examined widely. In this study, 230 P. vivax genes were analyzed for VNTRs by SERV, and 33 kinds of TR deletions or insertions from 29P. vivax genes (12.6%) were found. Of these, 9 VNTR fragments from 8 P. vivax genes were used for PCR amplification and sequence analysis to examine the genetic diversity among 134 isolates from four Southeast Asian countries (China, Republic of Korea, Thailand, and Myanmar) with different malaria endemicity. We confirmed the existence of extensive polymorphism of VNTR fragments in field isolates. This detection provides several suitable markers for analysis of the molecular epidemiology of P. vivax field isolates. (C) 2017 Elsevier B.V. All rights reserved.</P>

Effects of hydrated lime on radionuclides stabilization of Hanford tank residual waste

Wang, Guohui,Um, Wooyong,Cantrell, Kirk J.,Snyder, Michelle M.V.,Bowden, Mark E.,Triplett, Mark B.,Buck, Edgar C. Elsevier 2017 CHEMOSPHERE - Vol.185 No.-

<P><B>Abstract</B></P> <P>Chemical stabilization of tank residual waste is part of a Hanford Site tank closure strategy to reduce overall risk levels to human health and the environment. In this study, a set of column leaching experiments using tank C-104 residual waste were conducted to evaluate the leachability of uranium (U) and technetium (Tc) where grout and hydrated lime were applied as chemical stabilizing agents. The experiments were designed to simulate future scenarios where meteoric water infiltrates through the vadose zones into the interior of the tank filled with layers of grout or hydrated lime, and then contacts the residual waste. Effluent concentrations of U and Tc were monitored and compared among three different packing columns (waste only, waste + grout, and waste + grout + hydrated lime). Geochemical modeling of the effluent compositions was conducted to determine saturation indices of uranium solid phases that could control the solubility of uranium. The results indicate that addition of hydrated lime strongly stabilized the uranium through transforming uranium to a highly insoluble calcium uranate (CaUO<SUB>4</SUB>) or similar phase, whereas no significant stabilization effect of grout or hydrated lime was observed on Tc leachability. The result implies that hydrated lime could be a great candidate for stabilizing Hanford tank residual wastes where uranium is one of the main concerns.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hanford tank residual waste could be stabilized by grout. </LI> <LI> Addition of hydrated lime stabilized uranium from leaching through CaUO<SUB>4</SUB>. </LI> <LI> XRD, SEM/EDS and thermodynamic model revealed uranium mineral transformation. </LI> </UL> </P>

Pulsed high intensity focused ultrasound increases penetration and therapeutic efficacy of monoclonal antibodies in murine xenograft tumors

Wang, S.,Shin, I.S.,Hancock, H.,Jang, B.s.,Kim, H.s.,Lee, S.M.,Zderic, V.,Frenkel, V.,Pastan, I.,Paik, C.H.,Dreher, M.R. Elsevier Science Publishers 2012 Journal of controlled release Vol.162 No.1

The success of radioimmunotherapy for solid tumors remains elusive due to poor biodistribution and insufficient tumor accumulation, in part, due to the unique tumor microenvironment resulting in heterogeneous tumor antibody distribution. Pulsed high intensity focused ultrasound (pulsed-HIFU) has previously been shown to increase the accumulation of <SUP>111</SUP>In labeled B3 antibody (recognizes Lewis<SUP>y</SUP> antigen). The objective of this study was to investigate the tumor penetration and therapeutic efficacy of pulsed-HIFU exposures combined with <SUP>90</SUP>Y labeled B3 mAb in an A431 solid tumor model. The ability of pulsed-HIFU (1MHz, spatial averaged temporal peak intensity=2685Wcm<SUP>-2</SUP>; pulse repetition frequency=1Hz; duty cycle=5%) to improve the tumor penetration and therapeutic efficacy of <SUP>90</SUP>Y labeled B3 mAb (<SUP>90</SUP>Y-B3) was evaluated in Le<SUP>y</SUP>-positive A431 tumors. Antibody penetration from the tumor surface and blood vessel surface was evaluated with fluorescently labeled B3, epi-fluorescent microscopy, and custom image analysis. Tumor size was monitored to determine treatment efficacy, indicated by survival, following various treatments with pulsed-HIFU and/or <SUP>90</SUP>Y-B3. The pulsed-HIFU exposures did not affect the vascular parameters including microvascular density, vascular size, and vascular architecture; although 1.6-fold more antibody was delivered to the solid tumors when combined with pulsed-HIFU. The distribution and penetration of the antibodies were significantly improved (p-value<0.05) when combined with pulsed-HIFU, only in the tumor periphery. Pretreatment with pulsed-HIFU significantly improved (p-value<0.05) survival over control treatments.

Fabrication of p-Type Nitrogen-Doped MgZnO by Depressing N-Related Donors

B. Yao,Z. P. Wei,Y. F. Li,D. Z. Shen,Y. M. Lu,Z. Z. Zhang,B. H. Li,C. J. Zheng,X. H. Wang,J. Y. Zhang,D. X. Zhao,X. W. Fan,Z. K. Tang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Wurtzite nitrogen-doped MgZnO (MgZnO:N) films were grown on c-plane sapphire by using plasma-assisted molecular beam epitaxy with radical NO as the oxygen source and nitrogen dopant. P-type conduction of MgZnO:N was obtained by decreasing the donor defects ((N2)O, VO, etc.) through annealing, revealing a hole concentration of 6.1 × 1017 cm−3 and a mobility of 6.42 cm2/Vs. Furthermore, as-grown p-type films with a hole concentration of 1 × 1017 cm−3 and a mobility of 3 cm2/Vs were obtained by decreasing the (N2)O double donor defect through control of the plasma conditions. ZnMgO:N/ZnO p-n junctions were obtained by using these p-type films. ode-like, rectifying I-V characteristics with a threshold voltage of about 5 V and a different reverse leakage current were observed at room temperature.

Photoluminescent properties and site occupation preference in Bi³⁺, Eu³⁺ doped CaY₄(SiO₄)₃O phosphor

Wang, L.,Moon, B.K.,Choi, B.C.,Kim, J.H.,Shi, J.,Jeong, J.H. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.11

Bi<SUP>3+</SUP>, Eu<SUP>3+</SUP> doped CaY<SUB>4</SUB>(SiO<SUB>4</SUB>)<SUB>3</SUB>O phosphors were synthesized through high temperature solid state reaction. Their photoluminescent properties were investigated and site occupation preference of Bi<SUP>3+</SUP> in cationic sites was analyzed. The structure of CaY<SUB>4</SUB>(SiO<SUB>4</SUB>)<SUB>3</SUB>O is characterized by three non-equivalent cationic sites with different coordination and cation-oxygen distances. By means of dielectric theory of the chemical bond for complex crystals, several kinds of chemical bond parameters like fractional covalence of CaY<SUB>4</SUB>(SiO<SUB>4</SUB>)<SUB>3</SUB>O were calculated and integrated to yield environmental factor h<SUB>e</SUB>. According to quantitative equations between the transition energy of Bi<SUP>3+</SUP> and environmental factor h<SUB>e</SUB>, the excitation bands at 308 and 226nm were assigned to <SUP>1</SUP>S<SUB>0</SUB>→<SUP>3</SUP>P<SUB>1</SUB> transition of Bi<SUP>3+</SUP> in Y(6h) and Y(4f) site, respectively. Another excitation band centered at 210nm should be the overlap of Bi<SUP>3+</SUP>A-band in Ca site and C-band in Y(6h) site. Optical band gap of pure CYSO was calculated using Kubelka-Munk method from diffuse reflectance spectra. Red emission can be realized in CaY<SUB>4</SUB>(SiO<SUB>4</SUB>)<SUB>3</SUB>O:Bi<SUP>3+</SUP>, Eu<SUP>3+</SUP> under UV light excitation because of efficient energy transfer from Bi<SUP>3+</SUP> to Eu<SUP>3+</SUP> and decay behaviors of Bi<SUP>3+</SUP> and Eu<SUP>3+</SUP> emission were investigated. Without optimization, the internal quantum efficiency of CYSO:2%Bi<SUP>3+</SUP>, 7%Eu<SUP>3+</SUP> at 310 and 393nm excitations were 31.563%, 74.252%, respectively.

Improvement of lower hybrid current drive systems for high-power and long-pulse operation on EAST

Wang M.,Liu L.,Zhao L.M.,Li M.H.,Ma W.D.,Hu H.C.,Wu Z.G.,Feng J.Q.,Yang Y.,Zhu L.,Chen M.,Zhou T.A.,Jia H.,Zhang J.,Cao L.,Zhang L.,Liang R.R.,Ding B.J.,Zhang X.J.,Shan J.F.,Liu F.K.,Ekedahl A.,Gonich 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

Aiming at high-power and long-pulse operation up to 1000 s, some improvements have been made for both 2.45 GHz and 4.6 GHz lower hybrid (LH) systems during the recent 5 years. At first, the guard limiters of the LH antennas with graphite tiles were upgraded to tungsten, the most promising material for plasma facing components in nuclear fusion devices. These new guard limiters can operate at a peak power density of 12.9 MW/m2 . Strong hot spots were usually observed on the old graphite limiters when 4.6 GHz system operated with power >2.0 MW [B. N. Wan et al., Nucl. Fusion 57 (2017) 102019], leading to a reduction of the maximum power capability. With the new limiters, 4.6 GHz LH system, the main current drive (CD) and electron heating tool for EAST, can be operated with power >2.5 MW routinely. Long-pulse operation up to 100 s with 4.6 GHz LH power of 2.4 MW was achieved in 2021 and the maximal temperature on the guard limiters measured by an infrared (IR) camera was about 540 C, much below the permissible value of tungsten material (~1200 C). A discharge with a duration of 1056 s was achieved and the 4.6 GHz LH energy injected into the plasma was up to 1.05 GJ. Secondly, the fully-activemultijunction (FAM) launcher of 2.45 GHz system was upgraded to a passive-active-multijunction (PAM), for which the density of optimum coupling was relatively low (below the cut-off value). Good coupling with reflection coefficient ~3% has been achieved with plasma-antenna distance up to 11 cm for the new PAM. Finally, in order to eliminate the effect of ion cyclotron range of frequencies (ICRF) wave on 4.6 GHz LH wave coupling, the location of the ICRF launcher was changed to a port that is located 157.5 toroidally from the 4.6 GHz LH system and is not magnetically connected

고속 분할법에 의한 교류-직류 전력계통의 조류계산에 관한연구

안병철,정형환,이권순,이준탁,정동일,왕용필 東亞大學校 海洋資源硏究所 1992 硏究論文集 Vol.5 No.1

The active and reactive power transfers to and from nodes connected to h.v.d.c. links do not obey the general rules of a.c. power transmission, the active power is independent of phase angle relationships and the reactive power is not directly related to voltage variation. Under such circumstances it is difficult to visualize h.v.d.c. model compatible with the behaviour of the fast decoupled algorithm. However, acknowledging the general acceptance of fast decoupled programes and the existence of some h.v.d.c. links(particularly considering their large power-carrying capacitors) a model of the h.v.d.c. transmission link suitable for incorporation with fast decoupled loadflow programes is described in the following sections.

Effect of Annealing Temperature on Binary TiO2:SiO2 Nanocrystalline Thin Films

F. Mei,C. Liu,J. B. Wang,L. Zhou,W. K. Zhao,Y. L. Fang,Y. Y. Ren 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6

Binary TiO2:SiO2 nanocrystalline thin films were prepared using liquid phase deposition at 35 C and annealed in air at temperatures ranging from 100 C to 500 C. The microstructural and the optical properties of the thin films were characterized by using an ultraviolet-visible spectrophotometer, a Fourier transform infrared spectrophotometer, a scanning electron microscope, and a transmission electron microscope. The photocatalytic performance of the thin films was evaluated by using photocatalytic degradation of methylene blue. The results showed that most TiO2 nanocrystallites were uniformly dispersed onto an amorphous SiO2 matrix and that nanopores had been formed on top of the TiO2 nanoparticles, resulting in an improved photocatalytic efficiency due to an increase number of effective adsorption sites. As we increased the annealing temperature, the small crystallites progressively aggregated into larger clusters, reducing the specific surface area of the TiO2 nanocrystallites. Moreover, SiO2 nanopowders moved towards the surface and covered the TiO2, resulting in a decreased photocatalytic activity.e