Association of brain heptachlor epoxide and other organochlorine compounds with lewy pathology

Ross, G. Webster,Abbott, Robert D.,Petrovitch, Helen,Duda, John E.,Tanner, Caroline M.,Zarow, Chris,Uyehara‐,Lock, Jane H.,Masaki, Kamal H.,Launer, Lenore J.,Studabaker, William B.,White, Lon R. John Wiley Sons, Inc. 2019 Movement disorders Vol.34 No.2

<P><B>ABSTRACT</B></P><P><B>Background</B></P><P>Organochlorine pesticides are associated with an increased risk of Parkinson's disease. A preliminary analysis from the Honolulu‐Asia Aging Study suggested that heptachlor epoxide, a metabolite from an organochlorine pesticide extensively used in Hawaii, may be especially important. This was a cross sectional analysis to evaluate the association of heptachlor epoxide and other organochlorine compounds with Lewy pathology in an expanded survey of brain organochlorine residues from the longitudinal Honolulu‐Asia Aging Study.</P><P><B>Methods</B></P><P>Organochlorines were measured in frozen occipital or temporal lobes in 705 brains using gas chromatography with mass spectrometry. Lewy pathology was identified using hematoxylin and eosin‐ and α‐synuclein immunochemistry‐stained sections from multiple brain regions.</P><P><B>Results</B></P><P>The prevalence of Lewy pathology was nearly doubled in the presence versus the absence of heptachlor epoxide (30.1% versus 16.3%, <I>P</I> < 0.001). Although associations with other compounds were weaker, hexachlorobenzene (<I>P</I> = 0.003) and α‐chlordane (<I>P</I> = 0.007) were also related to Lewy pathology. Most of the latter associations, however, were a result of confounding from heptachlor epoxide. Neither compound was significantly related to Lewy pathology after adjustment for heptachlor epoxide. In contrast, the association of heptachlor epoxide with Lewy pathology remained significant after adjustments for hexachlorobenzene (<I>P</I> = 0.013) or α‐chlordane (<I>P</I> = 0.005). Findings were unchanged after removal of cases of PD and adjustment for age and other characteristics.</P><P><B>Conclusions</B></P><P>Organochlorine pesticides are associated with the presence of Lewy pathology in the brain, even after exclusion of PD cases. Although most of the association is through heptachlor epoxide, the role of other organochlorine compounds is in need of clarification. © 2018 International Parkinson and Movement Disorder Society</P>

2P-210 Fabrication of Chiral Nanostructure by Directed Self-Assembly

최홍균,장재범,( Caroline Ross ) 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

In this study, we demonstrate that confinement of a cylindricalmorphology BCP in a shallow circular pit can produce either concentric rings or a spiral. A spiral is promoted by the presence of a notch-shaped feature within the template which controls the spiral chirality. The length of the spiral increases with the diameter of the template. Design of the notch geometry enabled double spirals to be formed. A notch of width □ L0 promotes spirals even for commensurate pit sizes indicating the critical importance of the inner shape of the template. For smaller notches, spirals formed for incommensurate template diameters and rings for commensurate template diameters. Analogous to using a notch to initiate a spiral in a circular pit, our approach could be extended to guide the chirality of 3D helical spirals formed in cylindrical confinements with a helical ramp template.

Self-assembled multiferroic perovskite-spinel nanocomposite thin films: epitaxial growth, templating and integration on silicon

Kim, Dong Hun,Ning, Shuai,Ross, Caroline A. The Royal Society of Chemistry 2019 Journal of materials chemistry. C, Materials for o Vol.7 No.30

<P>This review describes recent progress in the growth and properties of self-assembled multiferroic perovskite-spinel nanocomposite thin films, in particular, BiFeO3-CoFe2O4, and their integration on silicon or pre-patterned substrates. Vertically aligned nanocomposite thin films, in which ferromagnetic spinel CoFe2O4 nanopillars grow in a ferroelectric perovskite BiFeO3 matrix, have been investigated for applications such as next generation memory devices. The strain transfer between the two oxide phases at the vertical interface enables cross-coupling of the properties, <I>i.e.</I> a magnetic (electric) field can modify the polarization (magnetization) state, making the nanocomposite a two-phase magnetoelectric multiferroic. The ability to grow high quality thin film nanocomposites and the control of their properties through epitaxial strain transfer are prerequisites for their incorporation into practical devices. Most work has been carried out on perovskite substrates using pulsed laser deposition, and integration on semiconductor-compatible substrates using scalable deposition processes presents a challenge. This review focuses on the epitaxial integration of BiFeO3-CoFe2O4 nanocomposite thin films using sputter deposition on silicon substrates, and discusses recent work on the formation of highly ordered nanocomposites using various template patterning methods. This robust, scalable route for large-area fabrication of multifunctional oxide nanocomposites using sputtering brings the exciting prospects offered by these materials closer towards technological realization.</P>

Square arrays of holes and dots patterned from a linear ABC triblock terpolymer.

Choi, Hong Kyoon,Gwyther, Jessica,Manners, Ian,Ross, Caroline A American Chemical Society 2012 ACS NANO Vol.6 No.9

<P>Microphase separation of a polyisoprene-b-polystyrene-b-polyferrocenylsilane (PI-b-PS-b-PFS) triblock terpolymer film during chloroform solvent-annealing formed a 44 nm period square-symmetry array of alternating PI and PFS cylinders in a PS matrix. This nanostructure was converted to either a positive pattern of posts or a negative pattern of holes with tunable diameter by oxygen reactive ion etching or by surface reconstruction in a solvent, respectively, and coexisting post and hole patterns were also formed. Square arrays of silicon posts, pits, and inverted pyramids were fabricated by pattern transfer from the triblock terpolymer film into silicon substrates. The morphology of the triblock terpolymer film varied with the chloroform vapor pressure during solvent annealing, which was explained by selective swelling of the PI block at high vapor pressures. This triblock terpolymer system provides a convenient block copolymer lithography process for generation of nanoscale posts or holes with square symmetry.</P>

Templated assembly of Co-Pt nanoparticlesvia thermal and laser-induced dewetting of bilayer metal films

Oh, Yong-Jun,Kim, Jung-Hwan,Thompson, Carl V.,Ross, Caroline A. The Royal Society of Chemistry 2013 Nanoscale Vol.5 No.1

<P>Templated dewetting of a Co/Pt metal bilayer film on a topographic substrate was used to assemble arrays of Co-Pt alloy nanoparticles, with highly uniform particle size, shape and notably composition compared to nanoparticles formed on an untemplated substrate. Solid-state and liquid-state dewetting processes, using furnace annealing and laser irradiation respectively, were compared. Liquid state dewetting produced more uniform, conformal nanoparticles but they had a polycrystalline disordered fcc structure and relatively low magnetic coercivity. In contrast, solid state dewetting enabled formation of magnetically hard, ordered L1(0) Co-Pt single-crystal particles with coercivity >12 kOe. Furnace annealing converted the nanoparticles formed by liquid state dewetting into the L1(0) phase.</P>

Two-Dimensional Nanoparticle Supracrystals: A Model System for Two-Dimensional Melting

Kim, Jin Young,Kwon, S. Joon,Chang, Jae-Byum,Ross, Caroline A.,Hatton, T. Alan,Stellacci, Francesco American Chemical Society 2016 Nano letters Vol.16 No.2

<P>In a Langmuir trough, successive compression cycles can drive a two-dimensional (2D) nanoparticle supracrystal (NPSC) closer to its equilibrium structure. Here, we show a series of equilibrated 2D NPSCs consisting of gold NPs of uniform size, varying solely in the length of their alkanethiol ligands. The ordering of the NPSC is governed by the ligand length, thus providing a model system to investigate the nature of 2D melting in a system of NPs. As the ligand length increases the supracrystal transitions from a crystalline to a liquid-like phase with evidence of a hexatic phase at an intermediate ligand length. The phase change is interpreted as an entropy-driven phenomenon associated with steric constraints between ligand shells. The density of topological defects scales with ligand length, suggesting an equivalence between ligand length and temperature in terms of melting behavior. On the basis of this equivalence, the experimental evidence indicates a two-stage 2D melting of NPSCs.</P>

Interfacial Energy-Controlled Top Coats for Gyroid/Cylinder Phase Transitions of Polystyrene-<i>block</i>-polydimethylsiloxane Block Copolymer Thin Films

Ryu, In Hyu,Kim, Yong Joo,Jung, Yeon Sik,Lim, Jong Sung,Ross, Caroline A.,Son, Jeong Gon American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.20

<P>Block copolymers (BCPs) with a high Flory-Huggins interaction parameter (chi) can form well-defined sub-10 nm periodic structures and can be used as a template for fabrication of various functional nanostructures. However, the large difference of surface energy between the blocks commonly found in high-chi BCPs makes it challenging to stabilize a useful gyroid morphology in thin film form. Here, we used an interfacial-energy-tailored top-coat on a blended film of a polystyrene-block-polydimethylsiloxane (PS-b-PDMS) BCP and a low-molecular-weight PDMS homopolymer with a hydrophilic end functional group. The top coat consisted of a random mixture of 40% hydrolyzed poly(vinyl acetate)-random-poly(vinly alcohol) (PVA-r-PVAc, PVA40) and PVAc homopolymer. At the optimized top-coat composition, gyroid nanostructures with sub-10 nm strut width were achieved down to similar to 125 nm film thickness, which is only 3 times the lattice parameter of the gyroid structure. This is in marked contrast with a mixed morphology of gyroid and cylinders obtained for other compositions of the top coat. Self-consistent field theoretic simulations were used to understand the effect of the interfacial energy between the top coat and BCP/homopolymer blends on the phase transition behavior of the BCP/homopolymer films.</P>

Structure and magnetic properties of pulsed laser deposited SrFe₁₂O₁₉ thin films on SrTiO₃ (100) and (111) substrates

Kim, Dong Hun,Han, Seung Ho,Kang, Young-Min,Yang, Daejin,Ross, Caroline A. ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.692 No.-

<P><B>Abstract</B></P> <P>Epitaxial SrFe<SUB>12</SUB>O<SUB>19</SUB> films were prepared on SrTiO<SUB>3</SUB> (001) and (111) substrates by pulsed laser deposition and annealed in air at high temperature. As-deposited and annealed SrFe<SUB>12</SUB>O<SUB>19</SUB> thin films were characterized using scanning electron microscopy, x-ray diffraction, and vibrating sample magnetometry. Films annealed at 800 °C and 1000 °C on (111) substrates showed an epitaxial growth whereas films on (001) substrates grew with both in-plane and out-of-plane c-axis. The magnetic hysteresis loops of annealed films on (111) substrates exhibited a strong magnetocrystalline anisotropy with out-of-plane easy axis originating from epitaxial growth while the films on (001) substrates were almost isotropic.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SrFe<SUB>12</SUB>O<SUB>19</SUB> thin films were grown on SrTiO<SUB>3</SUB> substrates by pulsed laser deposition. </LI> <LI> The as-deposited SrFe<SUB>12</SUB>O<SUB>19</SUB> films exhibited low magnetization with poor crystallinity. </LI> <LI> Annealed SrFe<SUB>12</SUB>O<SUB>19</SUB> films showed crystallites with faceted surfaces. </LI> <LI> Annealed SrFe<SUB>12</SUB>O<SUB>19</SUB> films on SrTiO<SUB>3</SUB> (111) substrate had a strong magnetic anisotropy. </LI> </UL> </P>

Morphology control in block copolymer films using mixed solvent vapors.

Gotrik, Kevin W,Hannon, Adam F,Son, Jeong Gon,Keller, Brent,Alexander-Katz, Alfredo,Ross, Caroline A American Chemical Society 2012 ACS NANO Vol.6 No.9

<P>Solvent vapor annealing of block copolymer thin films can produce a range of morphologies different from the equilibrium bulk morphology. By systematically varying the flow rate of two different solvent vapors (toluene and n-heptane) and an inert gas, phase maps showing the morphology versus vapor pressure of the solvents were constructed for 45 kg/mol polystyrene-block-polydimethylsiloxane diblock copolymer films of different thicknesses. The final morphology was correlated with the swelling of the block copolymer and homopolymer films and the solvent vapor annealing conditions. Self-consistent field theory is used to model the effects of solvent swelling. These results provide a framework for predicting the range of morphologies available under different solvent vapor conditions, which is important in lithographic applications where precise control of morphology and critical dimensions are essential.</P>

Magnetic Phase Formation in Self-Assembled Epitaxial BiFeO₃–MgO and BiFeO₃–MgAl₂O₄ Nanocomposite Films Grown by Combinatorial Pulsed Laser Deposition

Kim, Dong Hun,Sun, XueYin,Kim, Tae Cheol,Eun, Yun Jae,Lee, Taeho,Jeong, Sung Gyun,Ross, Caroline A. American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.4

<P>Self-assembled epitaxial BiFeO3-MgO and BiFeO3-MgAl2O4 nanocomposite thin films were grown on SrTiO3 substrates by pulsed laser deposition. A two-phase columnar structure was observed for BiFeO3-MgO codeposition within a small window of growth parameters, in which the pillars consisted of a magnetic spinel phase (Mg,Fe)(3)O-4 within a BiFeO3 matrix, similar to the growth of BiFeO3 MgFe2O4 nanocomposites reported elsewhere. Further, growth of a nanocomposite with BiFeO3-(CoFe2O4/MgO/MgFe2O4), in which the minority phase was grown from three different targets, gave spinel pillars with a uniform (Mg,Fe,Co)(3)O-4 composition due to interdiffusion during growth) with a bifurcated shape from the merger of neighboring pillars. BiFeO3MgAl2O4 did not form a well-defined vertical nanocomposite in spite of having lower lattice mismatch, but instead formed a two-phase film with in which the spinel phase contained Fe. These results illustrate the redistribution of Fe between the oxide phases during oxide codeposition to form a ferrimagnetic phase from antiferromagnetic or nonmagnetic targets.</P>