Precision Greenness and Stroke/Transient Ischemic Attack in 249,405 US Medicare Beneficiaries

Scott C. Brown,William W. Aitken,Joanna Lombard,Kefeng Wang,Tatjana Rundek,Margaret M. Byrne,Matthew Toro,Maria I. Nardi,Jack Kardys,Abraham Parrish,José Szapocznik 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.1

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Highly efficient infrared optical nonlinearity of a wide-bandgap chalcogenide Li(2)CdGeS(4).

Jang, J I,Clark, D J,Brant, J A,Aitken, J A,Kim, Y S Optical Society of America 2014 Optics letters Vol.39 No.15

<P>A quaternary chalcogenide Li(2)CdGeS(4) is an excellent candidate for a nonlinear optical (NLO) material exhibiting wide transparency spanning from its fundamental band edge (3.15 eV) to the terahertz regime (23.5 μm). Strong optical nonlinearity of Li(2)CdGeS(4) has been investigated over a wide spectral range (λ=1.064-3.3??μm) based on second- and third-harmonic generation. The compound has a high damage threshold at λ=1.064??μm because of saturable three-photon absorption, and is phase-matchable for λ>1.5??μm with χ(2) ?50??pm/V. It also exhibits strong third-order nonlinearity of χ(3) ?10(5)?pm(2)/V(2). Li(2)CdGeS(4) is promising for high-power NLO applications in the broad infrared spectrum.</P>

Dynamics of Precise Ethylene Ionomers Containing Ionic Liquid Functionality

Choi, U Hyeok,Middleton, L. Robert,Soccio, Michelina,Buitrago, C. Francisco,Aitken, Brian S.,Masser, Hanqing,Wagener, Kenneth B.,Winey, Karen I.,Runt, James American Chemical Society 2015 Macromolecules Vol.48 No.2

<P>This paper presents the first findings on the molecular dynamics of the remarkable new class of linear and precisely functionalized ethylene copolymers. Specifically, we utilize broadband dielectric relaxation spectroscopy to investigate the molecular dynamics of linear polyethylene (PE)-based ionomers containing 1-methylimidazolium bromide (<B>ImBr</B>) pendants on exactly every 9th, 15th, or 21st carbon atom, along with one pseudorandom analogue. We also employed FTIR spectroscopy to provide insight into local ionic interactions and the nature of the ordering of the ethylene spacers between pendants. Prior X-ray scattering experiments revealed that the polar ionic groups in these ionomers self-assemble into microphase-separated aggregates dispersed throughout the nonpolar PE matrix. We focus primarily on the dynamics of the segmental relaxations, which are significantly slowed down compared to linear PE due to ion aggregation. Relaxation times depend on composition, the presence of crystallinity, and microphase-separated morphologies. Segmental relaxation strengths are much lower than predicted by the Onsager theory for mobile isolated dipoles but much higher than linear PE, demonstrating that at least some <B>ImBr</B> pendants participate in the segmental process. Analysis of the relaxation strengths using the Kirkwood <I>g</I> correlation factor demonstrates that ca. 10–40% of the <B>ImBr</B> ion dipoles (depending on copolymer composition and temperature) participate in the segmental motions of the precise ionomers under study, with the remainder immobilized or having net antiparallel arrangements in ion aggregates.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2015/mamobx.2015.48.issue-2/ma502168e/production/images/medium/ma-2014-02168e_0011.gif'></P>

Outstanding Laser Damage Threshold in Li₂MnGeS₄ and Tunable Optical Nonlinearity in Diamond-Like Semiconductors

Brant, Jacilynn A.,Clark, Daniel J.,Kim, Yong Soo,Jang, Joon I.,Weiland, Ashley,Aitken, Jennifer A. American Chemical Society 2015 Inorganic Chemistry Vol.54 No.6

<P>The new Li<SUB>2</SUB>MnGeS<SUB>4</SUB> and Li<SUB>2</SUB>CoSnS<SUB>4</SUB> compounds result from employing a rational and simple design strategy that guides the discovery of diamond-like semiconductors (DLSs) with wide regions of optical transparency, high laser damage threshold, and efficient second-order optical nonlinearity. Single-crystal X-ray diffraction was used to solve and refine the crystal structures of Li<SUB>2</SUB>MnGeS<SUB>4</SUB> and Li<SUB>2</SUB>CoSnS<SUB>4</SUB>, which crystallize in the noncentrosymmetric space groups <I>Pna</I>2<SUB>1</SUB> and <I>Pn</I>, respectively. Synchrotron X-ray powder diffraction (SXRPD) was used to assess the phase purity, and diffuse reflectance UV–vis–NIR spectroscopy was used to estimate the bandgaps of Li<SUB>2</SUB>MnGeS<SUB>4</SUB> (<I>E</I><SUB>g</SUB> = 3.069(3) eV) and Li<SUB>2</SUB>CoSnS<SUB>4</SUB> (<I>E</I><SUB>g</SUB> = 2.421(3) eV). In comparison with Li<SUB>2</SUB>FeGeS<SUB>4</SUB>, Li<SUB>2</SUB>FeSnS<SUB>4</SUB>, and Li<SUB>2</SUB>CoSnS<SUB>4</SUB> DLSs, Li<SUB>2</SUB>MnGeS<SUB>4</SUB> exhibits the widest region of optical transparency (0.60–25 μm) and phase matchability (≥1.6 μm). All four of the DLSs exhibit second-harmonic generation and are compared with the benchmark NLO material, AgGaSe<SUB>2</SUB>. Most remarkably, Li<SUB>2</SUB>MnGeS<SUB>4</SUB> does not undergo two- or three-photon absorption upon exposure to a fundamental Nd:YAG beam (λ = 1.064 μm) and exhibits a laser damage threshold > 16 GW/cm<SUP>2</SUP>.</P><P>New nonlinear optical (NLO) materials, Li<SUB>2</SUB>MnGeS<SUB>4</SUB> and Li<SUB>2</SUB>CoSnS<SUB>4</SUB>, are obtained using a steadfast design strategy for diamond-like semiconductors. Li<SUB>2</SUB>MnGeS<SUB>4</SUB> is the most promising NLO material for high-powered applications that use infrared radiation in comparison to Li<SUB>2</SUB>CoSnS<SUB>4</SUB>, Li<SUB>2</SUB>FeGeS<SUB>4</SUB>, and Li<SUB>2</SUB>FeSnS<SUB>4</SUB>. Li<SUB>2</SUB>MnGeS<SUB>4</SUB> exhibits second-harmonic generation (χ<SUP>(2)</SUP> = 15 pm/V), wide phase matchability (λ ≥ 1.6 μm), and a wide window of optical clarity (λ = 0.7−24 μm). Most remarkably, the laser damage threshold of Li<SUB>2</SUB>MnGeS<SUB>4</SUB> is > 16 GW/cm<SUP>2</SUP>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2015/inocaj.2015.54.issue-6/ic502981r/production/images/medium/ic-2014-02981r_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic502981r'>ACS Electronic Supporting Info</A></P>

Li₂CdGeS₄, A Diamond-Like Semiconductor with Strong Second-Order Optical Nonlinearity in the Infrared and Exceptional Laser Damage Threshold

Brant, Jacilynn A.,Clark, Daniel J.,Kim, Yong Soo,Jang, Joon I.,Zhang, Jian-Han,Aitken, Jennifer A. American Chemical Society 2014 Chemistry of materials Vol.26 No.10

<P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2014/cmatex.2014.26.issue-10/cm501029s/production/images/medium/cm-2014-01029s_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm501029s'>ACS Electronic Supporting Info</A></P>

Infrared nonlinear optical properties of lithium-containing diamond-like semiconductors Li₂ZnGeSe₄ and Li₂ZnSnSe₄

Zhang, Jian-Han,Clark, Daniel J.,Brant, Jacilynn A.,Sinagra, Charles W.,Kim, Yong Soo,Jang, Joon I.,Aitken, Jennifer A. The Royal Society of Chemistry 2015 Dalton Transactions Vol.44 No.24

<P>Two new lithium-containing diamond-like semiconductors, Li<SUB>2</SUB>ZnGeSe<SUB>4</SUB> and Li<SUB>2</SUB>ZnSnSe<SUB>4</SUB>, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz–kesterite structure type, crystallizing in the noncentrosymmetric space group <I>Pn</I>. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, <I>χ</I><SUP>(2)</SUP>, was estimated to be 19 and 23 pm V<SUP>−1</SUP> for Li<SUB>2</SUB>ZnGeSe<SUB>4</SUB> and Li<SUB>2</SUB>ZnSnSe<SUB>4</SUB>, respectively. Using a 1064 nm incident laser beam with a pulse width (<I>τ</I>) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm<SUP>−2</SUP>, which is higher than that of the AgGaSe<SUB>2</SUB> reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li<SUB>2</SUB>ZnGeSe<SUB>4</SUB> and Li<SUB>2</SUB>ZnSnSe<SUB>4</SUB> have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding.</P> <P>Graphic Abstract</P><P>Two new lithium-containing diamond-like semiconductors were synthesized, and the nonlinear optical properties were studied. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5dt01635e'> </P>

Optical Nonlinearity in Cu₂CdSnS₄ and α/β-Cu₂ZnSiS₄: Diamond-like Semiconductors with High Laser-Damage Thresholds

Rosmus, Kimberly A.,Brant, Jacilynn A.,Wisneski, Stephen D.,Clark, Daniel J.,Kim, Yong Soo,Jang, Joon I.,Brunetta, Carl D.,Zhang, Jian-Han,Srnec, Matthew N.,Aitken, Jennifer A. American Chemical Society 2014 Inorganic Chemistry Vol.53 No.15

<P>Cu<SUB>2</SUB>CdSnS<SUB>4</SUB> and α/β-Cu<SUB>2</SUB>ZnSiS<SUB>4</SUB> meet several criteria for promising nonlinear optical materials for use in the infrared (IR) region. Both are air-stable, crystallize in noncentrosymmetric space groups, and possess high thermal stabilities. Cu<SUB>2</SUB>CdSnS<SUB>4</SUB> and α/β-Cu<SUB>2</SUB>ZnSiS<SUB>4</SUB> display wide ranges of optical transparency, 1.4–25 and 0.7–25 μm, respectively, and have relatively large second-order nonlinearity as well as phase matchability for wide regions in the IR. The laser-damage threshold (LDT) for Cu<SUB>2</SUB>CdSnS<SUB>4</SUB> is 0.2 GW/cm<SUP>2</SUP>, whereas α/β-Cu<SUB>2</SUB>ZnSiS<SUB>4</SUB> has a LDT of 2.0 GW/cm<SUP>2</SUP> for picosecond near-IR excitation. Both compounds also exhibit efficient third-order nonlinearity. Electronic structure calculations provide insight into the variation in properties.</P><P>Changing Sn<SUP>4+</SUP> to Si<SUP>4+</SUP> in the I<SUB>2</SUB>−II−IV−VI<SUB>4</SUB> formula has significant effects on the characteristics critical for nonlinear optical applications. The air-stable, noncentrosymmetric, diamond-like Cu<SUB>2</SUB>CdSnS<SUB>4</SUB> and α/β-Cu<SUB>2</SUB>ZnSiS<SUB>4</SUB> exhibit significant second- and third-order nonlinearity. These materials are practical for applications because of their elevated thermal stabilities, wide optical transparency windows, broad regions of phase matchability for second harmonic generation, and high laser-damage thresholds (LDTs). The LDT of the wide-gap α/β-Cu<SUB>2</SUB>ZnSiS<SUB>4</SUB> surpasses that of commercially available materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-15/ic501310d/production/images/medium/ic-2014-01310d_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic501310d'>ACS Electronic Supporting Info</A></P>