Effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells

Huang, H.S.,Han, X.H.,Hwang, B.Y.,Park, J.I.,Yoo, S.K.,Lee, H.J.,Lim, S.C.,Lee, M.K. Elsevier Science B.V 2008 Environmental toxicology and pharmacology Vol.26 No.1

The effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells were investigated. Catalpalactone at 5-30μM decreased intracellular dopamine content with the IC<SUB>50</SUB> value of 22.1μM. Catalpalactone at 5-20μM, but not 30μM, did not alter cell viability. Catalpalactone at 20μM inhibited tyrosine hydroxylase (TH) and aromatic-l-amino acid decarboxylase (AADC) activities. Catalpalactone also decreased cyclic AMP levels and inhibited TH phosphorylation. In addition, catalpalactone at 20μM reduced the increases in dopamine levels induced by L-DOPA (20-50μM). Catalpalactone (5-30μM) associated with L-DOPA (50-100μM) enhanced L-DOPA-induced cytotoxicity at 48h, which was prevented by N-acetyl-l-cysteine. These results suggest that catalpalactone inhibited dopamine biosynthesis by reducing TH and AADC activities and enhanced L-DOPA-induced cytotoxiciy in PC12 cells.

Graphene/M_xWO₃ (M=Na, K) nanohybrids with excellent electrical properties

Liu, B.,Yin, S.,Wu, X.,Wang, Y.,Huang, Y.,Wu, J.,Sekino, T.,Matsushita, J.,Lee, S.W.,Kobayashi, M.,Kakihana, M.,Sato, T. Pergamon Press ; Elsevier Science Ltd 2015 Carbon Vol.94 No.-

Graphene/M<SUB>x</SUB>WO<SUB>3</SUB> (M=Na, K) nanocomposites with different weight ratios were successfully synthesized using MBH<SUB>4</SUB> as a reducing agent in aqueous solution, followed by crystallization of amorphous precursors under calcination in H<SUB>2</SUB> (5vol.%)/N<SUB>2</SUB> atmosphere at 600<SUP>o</SUP>C. The coupled samples showed good shielding properties in NIR wavelength range together with certain visible lights transparency. The as-prepared tungsten bronze nanoparticles are homogeneously anchored on graphene sheets, and the graphene/tungsten bronze nanocomposite showed an enhanced electrical conductivity with good shielding properties in the NIR range together with certain visible lights transparency. With the increment of graphene amount in the composites, the contact between the graphene sheets was enhanced, and the M<SUB>x</SUB>WO<SUB>3</SUB> might enhance the charge transport properties of graphene by generating the short conductive path for electrons over the remained oxygenated functional groups. The synergistic effects could be observed in the composites. When 5wt.% or more graphene were composed into M<SUB>x</SUB>WO<SUB>3</SUB>, the hybrid composite showed the higher electrical conductivity than those of uncoupled graphene and tungsten bronze alone.

New self-activated eulytite-type compounds of M₇Zr(PO₄)₆ (M=Ca, Sr, Ba)

Qin, L.,Wei, D.,Huang, Y.,Kim, S.I.,Yu, Y.M.,Seo, H.J. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.574 No.-

Eulytite-type orthophosphates M<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> (M=Ca, Sr, Ba) were prepared by conventional high temperature solid-state reaction. Sr<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> and Ba<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> crystallize in the pure eulytite-type phase with cubic space group (I4@?3d). The impurity phase β-Ca<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> was inevitably coexisted with the Ca<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> phase. The luminescence properties are investigated by UV-VUV excitation and emission spectroscopy and X-ray-excited luminescence (XEL) spectroscopy. The broad excitation and emission bands are observed due to the charge transfer transition from Zr<SUP>4+</SUP> to O<SUP>2-</SUP> in M<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> (M=Ca, Sr, Ba) eulytite. The characteristics of the phosphors including the luminescence mechanism are explained by Stokes shift, decay curves, and CIE color coordinates. The Sr<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>3</SUB> and Ba<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>3</SUB> phosphors exhibit unusual spectral features with the emission bands at 470 and 480nm, respectively. The weak luminescence centered at 495nm is observed in the Ca<SUB>7</SUB>Zr(PO<SUB>4</SUB>)<SUB>6</SUB> eulytite with lifetime of 4.67μs. The unusual self-activated luminescence is discussed on the base of the crystal structure of eulytite.

IL-17 stimulates the proliferation and differentiation of human mesenchymal stem cells: implications for bone remodeling

Huang, H,Kim, H J,Chang, E-J,Lee, Z H,Hwang, S J,Kim, H-M,Lee, Y,Kim, H-H Macmillan Publishers Limited 2009 CELL DEATH AND DIFFERENTIATION Vol.16 No.10

Interleukin-17 (IL-17) is a cytokine secreted primarily by T<SUB>H</SUB>-17 cells. Although IL-17 is primarily associated with the induction of tissue inflammation, the other biological roles of IL-17, including non-immune functions, have yet to be thoroughly explored. Here, we report that T-cell-produced IL-17 can induce proliferation of human bone marrow-derived mesenchymal stem cells (hMSCs) in a manner dependent on the generation of reactive oxygen species (ROS). Rac1 GTPase and NADPH oxidase 1 (Nox1) are activated by IL-17 to produce ROS, which in turn stimulates hMSC proliferation. The activation of the MEK-ERK pathway is also crucial for IL-17-dependent hMSC proliferation. TRAF6 and Act1 are required to activate Nox 1 and to phosphorylate MEK on IL-17 stimulation. Interestingly, IL-17 not only accelerates the proliferation of hMSCs, but also induces their migration, motility, and osteoblastic differentiation. Furthermore, IL-17 induces the expression of M-CSF and receptor activator of NF-κB ligand (RANKL) on hMSCs, thereby supporting osteoclastogenesis both in vivo and in vitro. On the basis of these results, we suggest that IL-17 can function as a signal to induce extensive bone turnover by regulating hMSC recruitment, proliferation, motility, and differentiation.

Interstitial water chemistry of freshwater sediments : Chemical omposition, metal speciation and toxicity

Jae E. Yang,P.M. Huang 江原大學校 附設 環境硏究所 1992 環境硏究 Vol.9 No.-

Although the free aquo ion (M^z+) is considered to be the most toxic form of a metal, studies have demonstrated that various metal-ligand complexes also contribute to the overall toxicity of metals. In aquatic environments, porewaters represent an important pathway by which biota are exposed to metals. Consequently, chemical composition and metal speciation in interstitial waters is of considerable interest. This study was initiated to (i) determine the chemical composition of interstitial waters from selected streams and lakes, (ii) model the aqueous speciation of the mafor and trace metals in these interstitial waters, and (iii) assess the influence the selected organic ligand on Hg biotoxicity using the luminescent bacteria. Poerwater samples were analyzed to obtain metal, inorganic ligand, and amino acid profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The interstitial waters were classified as slightly to moderately saline, Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K. and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca, Mg, and Mn such as the types of MCO3(s), MCO3°, and MHCO3^+. Trace metal concentrations were generally within the ranges reported for nonpolluted freshwater systems. Whereas the speciation of Cr(III) and Co(II) was dominated by carbonate equilibria, speciations of Hg, Zn, and Fe(II) were dominated by hydroxy-metal complexes, M(OH)^+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3(s). In interstitial waters with high concentrations of chloride(>2mM), however, significant amounts of Hg were bound as HgCl2 and HgClOH. The aqueous speciation of Al was dominated by Al(OH)4 and Al2Si2O4(OH)6(s). Total concentrations of dissolved free amino acids varied from 1393 to 1935 ug CL^-1. The most effective metal scavenging amino acids were Histidine due to high stability constant for metal and Tryptophan due to high concentrations in the porewaters, Le., 757 to 1020 ug C L^-1. Secondary concentrations of various trace metal-amino acid complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu in all the porewaters and Ni in two of the poerwaters. Cysteine which has a strong stability constant for Hg decreased the biotoxicity of He and this effect was enhaned by increasing concentration of cysteine, even though high levels of choloride were present. Glycine and citric acid, on the otber band, had a little effect on Hg toxicity due to speciation of Hg as Hg-Cl complexes. The results of this research may help to provide a more comprehensive picture of the possible chelating effect of naturally occurring inorganic and organic ligands on trace metal chemistry and toxicity in the interstitial waters of oreshwater sediments.

Structural and temperature dependence of physical properties of Ni2MnM (M=Al, Ga and In) Heusler alloys

Nina Lee,이영백,B. J. Kim,이주열,M. D. Huang,Y. V. Kudryavtsev 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.1

Some physical properties of bulk Heusler alloys, Ni2MnM (M = Al, Ga and In), and their thin lms were studied. Structural characterization was performed by using X-ray diraction. The optical conductivity spectra of the bulk samples exhibit a two-peak structure in the 0.5 - 4.5 eV energy range. The evolution of the high-energy peak can be explained by the variation of the lattice constant. A SQUID magnetometer was employed to measure the temperature dependence of the magnetic properties in the 5 - 395 K temperature range. The disordered phase of the Ni2MnGa and Ni2MnIn alloy lms behaves like Pauli paramagnets. Annealing of the disordered lms restores the ordered structure, with almost full recovery of the magnetic and transport properties of the ordered lms.

Effects of Brazing Temperature on Microstructure and High-Temperature Strength of Joints Using a Novel Fourth-Generation Nickel-Based Single Crystal Superalloy

Z. P. Zhang,J. D. Liu,K. Q. Qiu,Y. Y. Huang,J. G. Li,X. G. Wang,J. L. Liu,M. Wang,M. K. Zou,Y. Z. Zhou 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

A novel fourth-generation nickel-based single crystal superalloy was bonded by vacuum brazing at 1230 °C, 1260 °C and1290 °C for 60 min using a new type of Co-based filler alloy. The effects of the brazing temperature on the microstructureand mechanical properties of the brazed joint were investigated. The brazed joint was mainly composed of the non-isothermalsolidification zone (M3B2 type-boride, CrB boride, Ni3Bboride and MC carbide), isothermal solidification zone (γ and γ'Phase) and base metal. With the increase of brazing temperature, the volume fraction of borides and γ' phase in the centerof the joint decreased and increased, respectively. The high-temperature tensile test results show that the tensile strength ofthe joints was improved with increasing brazing temperature, and the maximum tensile strength of the joint was 766 MPaafter brazing at 1290 °C for 60 min. Fracture observation shows that the fracture modes of the joints were the same, whichbelongs to the typical quasi cleavage fracture. The element distribution in the joint was homogenized to a certain extent at1290 °C. The segregation of Si and Ru was found, but they were still dissolved in the γ solid solution. The experimentalresults help to better understand the microstructure characteristics of the novel fourth-generation nickel-based single crystalsuperalloy and provide guidance for further optimizing the process parameters of the brazed joint.

SEARCH FOR PULSED γ-RAY EMISSION FROM GLOBULAR CLUSTER M28

Wu, J. H. K.,Hui, C. Y.,Wu, E. M. H.,Kong, A. K. H.,Huang, R. H. H.,Tam, P. H. T.,Takata, J.,Cheng, K. S. IOP Publishing 2013 ASTROPHYSICAL JOURNAL LETTERS - Vol.765 No.2

<P>Using the data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope, we have searched for gamma-ray pulsations from the direction of the globular cluster M28 (NGC 6626). We report the discovery of a signal with a frequency consistent with that of the energetic millisecond pulsar (MSP) PSR B1821-24 in M28. A weighted H-test test statistic of 28.8 is attained, which corresponds to a chance probability of similar to 10(-5) (4.3 sigma detection). With a phase-resolved analysis, the pulsed component is found to contribute similar to 25% of the total observed gamma-ray emission from the cluster. However, the unpulsed level provides a constraint for the underlying MSP population and the fundamental plane relations for the scenario of inverse Compton scattering. Follow-up timing observations in radio/X-ray are encouraged to further investigate this periodic signal candidate.</P>

방사광 X-선으로 찰영한 갑상선 조직 영상

봉진구,황정연<SUP>1<.SUP>,박성환,Jin Gu Bong,M.D.,Jung Yun Huang,Ph.D.<SUP>1<.SUP> and Sung Hwan Park,M.D. 대한갑상선-내분비외과학회 2010 The Koreran journal of Endocrine Surgery Vol.10 No.1

Purpose: X-ray microscopy with synchrotron radiation will soon be a useful tool for innovative x-ray imaging in clinical and laboratory settings. It enables us to observe the detailed internal structure of human tissue samples with great magnification power and excellent resolution. So, it has the possibility to be used for the clinical and research purposes to investigate thyroid diseases if it can effectively evaluate the various conditions of thyroid tissue. To determine the relation with their optical microscopic features, we compared the synchrotron X-ray images of unstained normal and thyroid cancer tissue samples with the histopathologic findings of their adjacent, stained thyroid tissue sections. Methods: An x-ray microscope was installed on a 1B2 beamline with a Pohang Light Source, which is a 3rd generation synchrotron radiation facility with an operating energy of 2.5 GeV at Pohang, Korea. The x-ray energy was set at 11.1 keV and the x-ray beam was monochromatized using a W/B4C monochromator. Formalin-fixed 10Ռm-thick female thyroid tissues from normal cases and carcinoma cases were attached on Kapton film for the imaging. The sample was positioned 25 m away from the beam source. The x-ray image of the sample was converted into a visual image on the CsI (TI) scintillation crystal, and it was magnified 20 times by the microscopic objective lens. After an additional 10 times digital magnification, this visual image was captured by a full frame CCD camera. Results: The monochromated x-ray microscopic images of the female thyroid tissues of the normal cases and carcinoma cases were obtained with good resolution. These synchrotron images showed the normal follicular structures in the normal thyroid tissue sections and the characteristic severe stromal fibrosis with collagen fiber accumulation in the cancer tissue sections. Conclusion: Owing to the great magnification and excellent resolution, the synchrotron x-ray microscopic images of the normal and cancerous thyroid tissues showed good correspondence with the histopathologic findings of their adjacent, stained tissue sections. So, the x-ray microscopic imaging of thyoid tissue using synchrotron radiation has good potential for use in various clinical and research settings in the future. (Korean J Endocrine Surg 2010;10: 19-23)

OGLE-2016-BLG-1190Lb: The First<i>Spitzer</i>Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Ryu, Y.-H.,Yee, J. C.,Udalski, A.,Bond, I. A.,Shvartzvald, Y.,Zang, W.,Jaimes, R. Figuera,Jørgensen, U. G.,Zhu, W.,Huang, C. X.,Jung, Y. K.,Albrow, M. D.,Chung, S.-J.,Gould, A.,Han, C.,Hwang, K.-H.,Sh American Astronomical Society 2018 The Astronomical journal Vol.155 No.1

<P>We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the Galactic bulge/ bar, an assignation that can be confirmed by two epochs of high-resolution imaging of the combined source-lens baseline object. The planet's mass, M-p = 13.4 +/- 0.9 M-J, places it right at the deuteriumburning limit, i. e., the conventional boundary between 'planets' and 'brown dwarfs.' Its existence raises the question of whether such objects are really ' planets' (formed within the disks of their hosts) or 'failed stars' (lowmass objects formed by gas fragmentation). This question may ultimately be addressed by comparing disk and bulge/bar planets, which is a goal of the Spitzer microlens program. The host is a G dwarf, M-host = 0.89. +/- 0.07 M-circle dot, and the planet has a semimajor axis a similar to 2.0 au. We use Kepler K2 Campaign 9 microlensing data to break the lens-mass degeneracy that generically impacts parallax solutions from Earth-Spitzer observations alone, which is the first successful application of this approach. The microlensing data, derived primarily from near-continuous, ultradense survey observations from OGLE, MOA, and three KMTNet telescopes, contain more orbital information than for any previous microlensing planet, but not quite enough to accurately specify the full orbit. However, these data do permit the first rigorous test of microlensing orbital-motion measurements, which are typically derived from data taken over < 1% of an orbital period.</P>