Contribution of small phytoplankton to total primary production in the Chukchi Sea

Lee, S.H.,Sun Yun, M.,Kyung Kim, B.,Joo, H.,Kang, S.H.,Keun Kang, C.,Whitledge, T.E. Pergamon Press ; Elsevier Science Ltd 2013 Continental shelf research Vol.68 No.-

Given a projection of thriving small phytoplankton in the Arctic Ocean under climate-induced environmental changes, it is important to estimate the contribution of small phytoplankton (0.7-5μm) to the total primary production in the Chukchi Sea, which is an important conduit of organic matter from the North Pacific to the Arctic Ocean. Based on a <SUP>13</SUP>C-<SUP>15</SUP>N dual isotope tracer technique, small phytoplankton productivity measurements were taken during two consecutive cruises in the Chukchi Sea in 2004. The total phytoplankton carbon uptake rates ranged from 0 to 25.38mgCm<SUP>-3</SUP>h<SUP>-1</SUP>, whereas the uptake rates of small phytoplankton ranged from 0 to 2.87mgCm<SUP>-3</SUP>h<SUP>-1</SUP>. In comparison with the carbon uptake rates, total phytoplankton nitrate uptake rates ranged from 0 to 4.40mgNm<SUP>-3</SUP>h<SUP>-1</SUP> while small phytoplankton nitrate uptake rates ranged from 0 to 0.39mgNm<SUP>-3</SUP>h<SUP>-1</SUP>. Ammonium uptake rates ranged from 0 to 8.34mgNm<SUP>-3</SUP>h<SUP>-1</SUP> and from 0.01 to 2.18mgNm<SUP>-3</SUP>h<SUP>-1</SUP>, for total and small phytoplankton, respectively. Small phytoplankton contributed 24.80% (S.D.=+/-23.0%) to the total chlorophyll-a concentration, and 59.41% (S.D.=+/-52.12%) to the total carbon biomass due to its higher particulate organic carbon per chlorophyll-a unit during the two cruises in 2004. In the Chukchi Sea, the average contributions of small phytoplankton to carbon and total nitrogen (nitrate+ammonium) uptake rates were 31.72% (S.D.=+/-23.59%) and 37.31% (S.D.=+/-26.06%), respectively.

<i>K</i>-mixing in the doubly mid-shell nuclide ¹⁷⁰Dy and the role of vibrational degeneracy

Sö,derströ,m, P.-A.,Walker, P.M.,Wu, J.,Liu, H.L.,Regan, P.H.,Watanabe, H.,Doornenbal, P.,Korkulu, Z.,Lee, P.,Liu, J.J.,Lorusso, G.,Nishimura, S.,Phong, V.H.,Sumikama, T.,Xu, F.R.,Yagi, A.,Zha North-Holland Pub. Co 2016 Physics letters. Section B Vol.762 No.-

<P><B>Abstract</B></P> <P>A detailed study of the structure of the doubly mid-shell nucleus Dy 104 1 66 170 has been carried out, following isomeric and <I>β</I> decay. We have measured the yrast band up to the spin-parity <SUP> J π </SUP> = <SUP> 6 + </SUP> state, the K = 2 <I>γ</I>-vibration band up to the <SUP> 5 + </SUP> state, a low-lying negative-parity band based on a <SUP> 2 − </SUP> state that could be a candidate for the lowest energy octupole vibration state within this nucleus, and a candidate for the <SUP> K π </SUP> = <SUP> 6 + </SUP> two quasi-particle isomer. This state was determined to have an excitation energy of 1643.91(23) keV and a half life of 0.99(4) μs, with a reduced hindrance for its decay to the ground-state band an order of magnitude lower than predicted by <SUB> N p </SUB> <SUB> N n </SUB> systematics. This is interpreted as being due to <I>γ</I>-vibrational mixing from a near degeneracy of the isomer and the <SUP> 6 + </SUP> state of the <I>γ</I> band. Furthermore, the parent nucleus <SUP>170</SUP>Tb has been determined to have a half-life of 0.91 ( − 13 + 18 ) s with a possible spin-parity of <SUP> 2 − </SUP> .</P>

Molecular and Functional Characterization of ORAI and STIM in Human Corporeal Smooth Muscle Cells and Effects of the Transfer of Their Dominant-Negative Mutant Genes into Diabetic Rats

Sung, H.H.,Kam, S.C.,Lee, J.H.,Chae, M.R.,Hong, C.,Ko, M.,Han, D.H.,So, I.,Lee, S.W. Williams and Wilkins Co 2012 The Journal of urology Vol.187 No.5

Purpose: We investigated the molecular identity and functional activity of STIM1 and ORAI in human cavernous smooth muscle. We also determined whether transferring dominant negative mutants of the STIM1 or ORAI gene would correct diabetes related erectile dysfunction in a rat model. Materials and Methods: Reverse transcriptase-polymerase chain reaction was done to identify ORAI and STIM in human cavernous smooth muscle. For the in vivo study intracavernous pressure, blood pressure and their ratio were assessed after cavernous nerve stimulation to diabetic rats transfected with pcDNA encoding the ORAI1<SUP>DN</SUP> or the STIM1<SUP>DN</SUP> gene. Results: ORAI (1, 2 and 3) and STIM (1 and 2) were identified in human cavernous smooth muscle cells. After [Ca<SUP>2+</SUP>] depletion by thapsigargin and cyclopiazonic acid we recorded store operated Ca<SUP>2+</SUP> entry in human cavernous smooth muscle cells. Entry was decreased by the store operated Ca<SUP>2+</SUP> channel blockers La<SUP>3+</SUP> and SKF96365. Mean +/- SE intracavernous pressure/blood pressure in rats with ORAI1<SUP>DN</SUP> or STIM1<SUP>DN</SUP> gene transfer was 78.8% +/- 2.2% and 77.1% +/- 1.2% in 11 and 10, respectively. This result was significantly higher than that in 10 diabetic controls (51.0% +/- 3.7%) and similar to that in 9 normal controls (85.8% +/- 2.6%). Using reverse transcriptase-polymerase chain reaction we confirmed transgene expression in rat cavernous tissue. Conclusions: Transfer of ORAI<SUP>DN</SUP> or STIM1<SUP>DN</SUP> genes restored erectile function in diabetic rats. It might be applicable to develop new therapy for erectile dysfunction.

Synthesis of and ethylene oligomerization with binuclear palladium catalysts having sterically modulated bis-imine ligands with methylene spacer

Budagumpi, S.,Liu, Y.,Suh, H.,Kim, I. Elsevier Sequoia 2011 Journal of organometallic chemistry Vol.696 No.9

Sterically modulated bis-imine ligands (L<SUP>1</SUP>-L<SUP>3</SUP>) were prepared by reacting 4,4'-methylene bis-(2,6-dialkyl aniline) and antipyrine-4-carboxaldehyde in a 1:2 stoichiometric ratio. The reactions of L<SUP>1</SUP>-L<SUP>3</SUP> with dichloro(cycloocta-1.5-diene)palladium(II) [PdCl<SUB>2</SUB>(cod)] yield the corresponding binuclear palladium complexes with the general formula Pd<SUB>2</SUB>Cl<SUB>4</SUB>L (L = L<SUP>1</SUP>, L<SUP>2</SUP>, and L<SUP>3</SUP>). The binucleating ligands bind to the palladium ion via the lone pair on the imine nitrogen and amide oxygen atoms, resulting in a square-planar geometry around the metal center. All the palladium catalysts efficiently oligomerize ethylene to produce C<SUB>4</SUB>-C<SUB>20</SUB> fractions at activities of up to 1308 kg-oligomer mol-Pd<SUP>-1</SUP> bar<SUP>-1</SUP> h<SUP>-1</SUP> at 30 <SUP>o</SUP>C in combination with ethylaluminum sesquichloride. The formation of active sites by the change in geometry of the metal complexes could be traced using spectroscopic and electrochemical techniques.

Alluaudite Na₂Co₂Fe(PO₄)₃ as an electroactive material for sodium ion batteries

Essehli, R.,Belharouak, I.,Ben Yahia, H.,Maher, K.,Abouimrane, A.,Orayech, B.,Calder, S.,Zhou, X. L.,Zhou, Z.,Sun, Y-K. The Royal Society of Chemistry 2015 Dalton Transactions Vol.44 No.17

<P>The electroactive orthophosphate Na<SUB>2</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB> was synthesized using a solid state reaction. Its crystal structure was solved using the combination of powder X-ray- and neutron-diffraction data. This material crystallizes according to the alluaudite structure (S.G. <I>C</I>2/<I>c</I>). The structure consists of edge sharing [MO<SUB>6</SUB>] octahedra (M = Fe, Co) resulting in chains parallel to [−101]. These chains are linked together <I>via</I> the [PO<SUB>4</SUB>] tetrahedra to form two distinct tunnels in which sodium cations are located. The electrochemical properties of Na<SUB>2</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB> were evaluated by galvanostatic charge–discharge cycling. During the first discharge to 0.03 V, Na<SUB>2</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB> delivers a specific capacity of 604 mA h g<SUP>−1</SUP>. This capacity is equivalent to the reaction of more than seven sodium ions per formula unit. Hence, this is a strong indication of a conversion-type reaction with the formation of metallic Fe and Co. The subsequent charge and discharge involved the reaction of fewer Na ions as expected for a conversion reaction. When discharged to 0.9 V, the material intercalated only one Na<SUP>+</SUP>-ion leading to the formation of a new phase Na<SUB>3</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB>. This phase could then be cycled reversibly with an average voltage of 3.6 V <I>vs.</I> Na<SUP>+</SUP>/Na and a capacity of 110 mA h g<SUP>−1</SUP>. This result is in good agreement with the theoretical capacity expected from the extraction/insertion of two sodium atoms in Na<SUB>3</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB>.</P> <P>Graphic Abstract</P><P>Na<SUB>2</SUB>Co<SUB>2</SUB>Fe(PO<SUB>4</SUB>)<SUB>3</SUB> crystallizes with the alluaudite-type structure (S.G. <I>C</I>2/<I>c</I>) and plays a dual anode/cathode behavior in sodium ion batteries. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5dt00971e'> </P>

Carbon treated self-ordered TiO₂ nanotube arrays with enhanced lithium-ion intercalation performance

Kim, H.S.,Yu, S.H.,Sung, Y.E.,Kang, S.H. Elsevier Sequoia 2014 Journal of alloys and compounds Vol.597 No.-

Vertically aligned TiO<SUB>2</SUB> nanotube (TONT) arrays on titanium substrate developed by facile electrochemical anodization in an aqueous solution of 0.5M Na<SUB>2</SUB>SO<SUB>4</SUB>, 0.5M H<SUB>3</SUB>PO<SUB>4</SUB>, 0.2M sodium citrate, and 0.5wt% NaF were prepared having a pore diameter and thickness of 100nm and 1.2μm, respectively. The undoped (u-doped) TONT arrays possessing an anatase phase were again annealed at 500<SUP>o</SUP>C under a mixed gas flux of nitrogen (N<SUB>2</SUB>) and acetylene (C<SUB>2</SUB>H<SUB>2</SUB>), to induce the enhancement of electrical conductivity. It was designated as carbon-doped (c-doped) TONT arrays. Undoped and c-doped TONT arrays were compared using various characterization tools, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, based on several electrochemical tests (galvanostatic charge/discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS)), it was observed that c-doped TONT arrays revealed improved charge/discharge capacity, cycle stability, and rate capability, due to the enhanced electrical conductivity of c-doped TONT arrays.

Oxidative degradation of endotoxin by advanced oxidation process (O₃/H₂O₂ & UV/H₂O₂)

Oh, B.T.,Seo, Y.S.,Sudhakar, D.,Choe, J.H.,Lee, S.M.,Park, Y.J.,Cho, M. Elsevier Scientific Pub. Co 2014 Journal of hazardous materials Vol.279 No.-

The presence of endotoxin in water environments may pose a serious public health hazard. We investigated the effectiveness of advanced oxidative processes (AOP: O<SUB>3</SUB>/H<SUB>2</SUB>O<SUB>2</SUB> and UV/H<SUB>2</SUB>O<SUB>2</SUB>) in the oxidative degradation of endotoxin. In addition, we measured the release of endotoxin from Escherichia coli following typical disinfection methods, such as chlorine, ozone alone and UV, and compared it with the use of AOPs. Finally, we tested the AOP-treated samples in their ability to induce tumor necrosis factor alpha (TNF-α) in mouse peritoneal macrophages. The production of hydroxyl radical in AOPs showed superior ability to degrade endotoxin in buffered solution, as well as water samples from Korean water treatment facilities, with the ozone/H<SUB>2</SUB>O<SUB>2</SUB> being more efficient compared to UV/H<SUB>2</SUB>O<SUB>2</SUB>. In addition, the AOPs proved effective not only in eliminating E. coli in the samples, but also in endotoxin degradation, while the standard disinfection methods lead to the release of endotoxin following the bacteria destruction. Furthermore, in the experiments with macrophages, the AOPs-deactivated endotoxin lead to the smallest induction of TNF-α, which shows the loss of inflammation activity, compared to ozone treatment alone. In conclusion, these results suggest that AOPs offer an effective and mild method for endotoxin degradation in the water systems.

High performance and the low voltage operating InGaZnO thin film transistor

Son, D.h.,Kim, D.H.,Sung, S.J.,Jung, E.A.,Kang, J.K. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.4

In this study, we compare the electrical properties of inverted-coplanar-type InGaZnO thin-film transistors (IGZO TFTs) deposited by RF sputtering at room temperature on a thermally grown SiO<SUB>2</SUB> gate dielectric or a hafnium oxide (HfO<SUB>2</SUB>) gate dielectric. The fabricated HfO<SUB>2</SUB>/IGZO TFTs have higher field-effect mobility than the SiO<SUB>2</SUB>/IGZO TFTs. The HfO<SUB>2</SUB>/InGaZnO TFTs show good performance with a high field-effect mobility of 25.8 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP>, a low sub-threshold swing of 90 mV dec<SUP>-1</SUP>, and a threshold voltage of 0.67 V, respectively.

Effect of surface composition of Pt-Fe nanoparticles for oxygen reduction reactions

Chung, Y.H.,Chung, D.Y.,Jung, N.,Park, H.Y.,Sung, Y.E.,Yoo, S.J. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.27

The aim of this work is primarily to rationalize the effect of surface composition on electrocatalytic activity. To investigate this point, we compared two types of nanoparticles with a different surface composition, namely Fe-rich and Pt-Fe mixed surfaces. We synthesized highly dispersed carbon-supported Pt<SUB>1</SUB>Fe<SUB>x</SUB> (x = 1, 2, and 3) nanoparticles with the Fe-rich surface (~2 nm), through a preferential interaction of a capping agent and the metal, i.e., Fe-OOC. The electronic structure and electrocatalytic properties of Pt<SUB>1</SUB>Fe<SUB>x</SUB> nanoparticles with the Fe-rich surface were found to be virtually independent from the Pt/Fe ratio. In contrast, nanoparticles with the Pt-Fe mixed surface, prepared by utilizing the difference of segregation energy, showed a clear dependence of the electronic and electrochemical characteristics on the amount of Pt and Fe, possibly because of the interaction between these two metals on the surface of the electrocatalysts. Compared to Pt, the Pt<SUB>1</SUB>Fe<SUB>2</SUB> nanoparticles with the Pt-Fe mixed surface showed the highest enhancement in the activity of the oxygen reduction reaction. This resulted from the development of a more electrochemically stable structure of the Pt-Fe mixed surface. This study demonstrated that the electrocatalytic properties of the Pt-Fe nanoparticles can be tuned using the surface composition rather than the bulk composition.

Effects of ginsenoside on large-conductance K_Ca channels in human corporal smooth muscle cells

Sung, H H,Chae, M R,So, I,Jeon, J-H,Park, J K,Lee, S W Macmillan Publishers Limited 2011 International journal of impotence research Vol.23 No.5

Ginseng was known to be an effective natural product that enhances penile erection. However, the precise biological function and mechanisms of action of ginseng with regard to erectile function remain unknown. The principal objective of this study was to identify ginsenoside (principal molecular ingredients of ginseng)-induced activation of large-conductance K<SUB>Ca</SUB> channel in human corporal smooth muscle cells, and to determine ginseng's mechanism of action on penile erection. Electrophysiological studies using cultured human corporal smooth muscle cells were conducted. We evaluated the effects of total ginsenosides (TGS) and ginsenoside Rg3 on large-conductance K<SUB>Ca</SUB> channel by determining whole-cell currents and single-channel activities. There was an increase in outward current dependent on TGS concentration (at +60 mV, 1 μg ml<SUP>−1</SUP>; 168.3±59.3%, n=6, P<0.05, 10 μg ml<SUP>−1</SUP>; 173.2±36.8%, n=4, P<0.05, 50 μg ml<SUP>−1</SUP>; 295.3±62.3%, n=19, P<0.001, 100 μg ml<SUP>−1</SUP>; and 462.3±97.1%, n=5, P<0.001) and Rg3 concentration (at +60 mV, 1 μM (0.78 μg ml<SUP>−1</SUP>); 222.8±64.8%, n=11, P<0.0001, 10 μM; 672.6±137.1%, n=10, P<0.0001, 50 μM; and 1713.3±234.7%, n=15, P<0.001) in the solution that was blocked completely by tetraethylammonium (TEA). Channel opening in cell-attached mode and channel activity in the inside-out membrane patches was also increased significantly by 50 μg of TGS or 10 μM of Rg3. The results of this study suggested that the activation of large-conductance K<SUB>Ca</SUB> channels by ginsenoside could be one mechanism of ginsenoside-induced relaxation in corporal smooth muscle.