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Hao Chen, Maria A Woodward, David T Burke, V Swetha E Jeganathan, Hakan Demirci, Volker Sick
A micro-plenoptic system was designed to capture the three-dimensional (3D) topography of the anterior iris surface by simple single-shot imaging. Within a depth-of-field of 2.4 mm, depth resolution of 10 µm can be achieved with accuracy (systematic errors) and precision (random errors) below 20%. We demonstrated the application of our micro-plenoptic imaging system on two healthy irides, an iris with naevi, and an iris with melanoma. The ridges and folds, with height differences of 10~80 µm, on the healthy irides can be effectively captured...
October 1, 2017: Biomedical Optics Express
Francesca Cipriani, Carla Mastrorilli, Salvatore Tripodi, Giampaolo Ricci, Serena Perna, Valentina Panetta, Riccardo Asero, Arianna Dondi, Annamaria Bianchi, Nunzia Maiello, Michele Miraglia Del Giudice, Tullio Frediani, Francesco Macrì, Sandra Lucarelli, Iride Dello Iacono, Maria Francesca Patria, Elena Varin, Diego Peroni, Loredana Chini, Viviana Moschese, Roberto Bernardini, Giuseppe Pingitore, Umberto Pelosi, Mariangela Tosca, Francesco Paravati, Ifigenia Sfika, Andrea Di Rienzo Businco, Calotta Povesi Dascola, Pasquale Comberiati, Simone Frediani, Caterina Lambiase, Maria Carmen Verga, Diego Faggian, Mario Plebani, Mauro Calvani, Carlo Caffarelli, Paolo Maria Matricardi
BACKGROUND: Grass pollen-related seasonal allergic rhinoconjunctivitis (SARg) is clinically heterogeneous in severity, comorbidities and response to treatment. The component-resolved diagnostics disclosed also a high heterogeneity at molecular level. Our study aimed at analyzing the characteristics of the IgE sensitization to Phleum pratense molecules and investigating the diagnostic relevance of such molecules in childhood. METHODS: We examined 1120 children (age 4-18y) with SARg...
October 20, 2017: Allergy
Joshua S Harvey, Hannah E Smithson, Clive R Siviour, Giles E M Gasper, Sigbjørn O Sønnesyn, Brian K Tanner, Tom C B McLeish
The rainbow has been the subject of discussion across a variety of historical periods and cultures, and numerous optical explanations have been suggested. Here, we further explore the scientific treatise De iride [On the Rainbow] written by Robert Grosseteste in the 13th century. Attempting to account for the shape of the rainbow, Grosseteste bases his explanation on the optical properties of transparent cones, which he claims can give rise to arc-shaped projections through refraction. By stating that atmospheric phenomena are reducible to the geometric optics of a conical prism, the De iride lays out a coherent and testable hypothesis...
July 1, 2017: Applied Optics
Alejandro Ruiz, Alex Frano, Nicholas P Breznay, Itamar Kimchi, Toni Helm, Iain Oswald, Julia Y Chan, R J Birgeneau, Zahirul Islam, James G Analytis
Magnetic honeycomb iridates are thought to show strongly spin-anisotropic exchange interactions which, when highly frustrated, lead to an exotic state of matter known as the Kitaev quantum spin liquid. However, in all known examples these materials magnetically order at finite temperatures, the scale of which may imply weak frustration. Here we show that the application of a relatively small magnetic field drives the three-dimensional magnet β-Li2IrO3 from its incommensurate ground state into a quantum correlated paramagnet...
October 16, 2017: Nature Communications
Mykola Abramchuk, Cigdem Ozsoy-Keskinbora, Jason W Krizan, Kenneth R Metz, David C Bell, Fazel Tafti
We present the first copper iridium binary metal oxide with the chemical formula Cu2IrO3. The material is synthesized from the parent compound Na2IrO3 by a topotactic reaction where sodium is exchanged with copper under mild conditions. Cu2IrO3 has the same monoclinic space group (C2/c) as Na2IrO3 with a layered honeycomb structure. The parent compound Na2IrO3 is proposed to be relevant to the Kitaev spin liquid on the basis of having Ir(4+) with an effective spin of 1/2 on a honeycomb lattice. Remarkably, whereas Na2IrO3 shows a long-range magnetic order at 15 K and fails to become a true spin liquid, Cu2IrO3 remains disordered until 2...
October 20, 2017: Journal of the American Chemical Society
Sebastian Bette, Tomohiro Takayama, Kentaro Kitagawa, Riku Takano, Hidenori Takagi, Robert E Dinnebier
A powder sample of pure H3LiIr2O6 was synthesized from α-Li2IrO3 powder by a soft chemical replacement of Li(+) with H(+). The crystal structure of H3LiIr2O6 consists of sheets of edge sharing LiO6- and IrO6-octahedra forming a honeycomb network with layers stacked in a monoclinic distorted HCrO2 type pattern. Heavy stacking faulting of the sheets is indicated by anisotropic peak broadening in the X-ray powder diffraction (XRPD) pattern. The ideal, faultless crystal structure was obtained by a Rietveld refinement of the laboratory XRPD pattern while using the LiIr2O6(3-)-layers of α-Li2IrO3 as a starting model...
November 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
S Waibel, K Pillunat, L Pillunat
No abstract text is available yet for this article.
September 26, 2017: Der Ophthalmologe: Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
Masahiko G Yamada, Hiroyuki Fujita, Masaki Oshikawa
Kitaev's honeycomb lattice spin model is a remarkable exactly solvable model, which has a particular type of spin liquid (Kitaev spin liquid) as the ground state. Although its possible realization in iridates and α-RuCl_{3} has been vigorously discussed recently, these materials have substantial non-Kitaev direct exchange interactions and do not have a spin liquid ground state. We propose metal-organic frameworks (MOFs) with Ru^{3+} (or Os^{3+}), forming the honeycomb lattice as promising candidates for a more ideal realization of Kitaev-type spin models, where the direct exchange interaction is strongly suppressed...
August 4, 2017: Physical Review Letters
Ekaterina M Pärschke, Krzysztof Wohlfeld, Kateryna Foyevtsova, Jeroen van den Brink
The resemblance of crystallographic and magnetic structures of the quasi-two-dimensional iridates Ba2IrO4 and Sr2IrO4 to La2CuO4 points at an analogy to cuprate high-Tc superconductors, even if spin-orbit coupling is very strong in iridates. Here we examine this analogy for the motion of a charge (hole or electron) added to the antiferromagnetic ground state. We show that correlation effects render the hole and electron case in iridates very different. An added electron forms a spin polaron, similar to the cuprates, but the situation of a removed electron is far more complex...
September 25, 2017: Nature Communications
Chunlei Zhang, Juan Chen, Fang Zhao, Ruoyun Chen, Dequan Yu, Zhengyu Cao
Iritectol G, a novel iridal-type triterpenoid containing an uncommon tetrahydrofuran moiety, was isolated from the rhizomes of Iris tectorum. The structure was elucidated by comprehensive spectroscopic analysis. Iritectol G inhibited spontaneous and 4-aminopyridine-evoked calcium oscillations in primary cultured neocortical neurons with IC50 values of 8.2μM and 12.5μM, respectively. Further electrophysiological study demonstrated that iritectol G preferred to interact with inactivated state of voltage-gated sodium channel with an IC50 value of 7...
October 2017: Fitoterapia
W C Yang, Y T Xie, W K Zhu, K Park, A P Chen, Y Losovyj, Z Li, H M Liu, M Starr, J A Acosta, C G Tao, N Li, Q X Jia, J J Heremans, S X Zhang
While pyrochlore iridate thin films are theoretically predicted to possess a variety of emergent topological properties, experimental verification of these predictions can be obstructed by the challenge in thin film growth. Here we report on the pulsed laser deposition and characterization of thin films of a representative pyrochlore compound Bi2Ir2O7. The films were epitaxially grown on yttria-stabilized zirconia substrates and have lattice constants that are a few percent larger than that of the bulk single crystals...
August 10, 2017: Scientific Reports
K A Modic, B J Ramshaw, J B Betts, Nicholas P Breznay, James G Analytis, Ross D McDonald, Arkady Shekhter
The complex antiferromagnetic orders observed in the honeycomb iridates are a double-edged sword in the search for a quantum spin-liquid: both attesting that the magnetic interactions provide many of the necessary ingredients, while simultaneously impeding access. Focus has naturally been drawn to the unusual magnetic orders that hint at the underlying spin correlations. However, the study of any particular broken symmetry state generally provides little clue about the possibility of other nearby ground states...
August 1, 2017: Nature Communications
Lin Hao, D Meyers, Clayton Frederick, Gilberto Fabbris, Junyi Yang, Nathan Traynor, Lukas Horak, Dominik Kriegner, Yongseong Choi, Jong-Woo Kim, Daniel Haskel, Phil J Ryan, M P M Dean, Jian Liu
We report an experimental investigation of the two-dimensional J_{eff}=1/2 antiferromagnetic Mott insulator by varying the interlayer exchange coupling in [(SrIrO_{3})_{1}, (SrTiO_{3})_{m}] (m=1, 2 and 3) superlattices. Although all samples exhibited an insulating ground state with long-range magnetic order, temperature-dependent resistivity measurements showed a stronger insulating behavior in the m=2 and m=3 samples than the m=1 sample which displayed a clear kink at the magnetic transition. This difference indicates that the blocking effect of the excessive SrTiO_{3} layer enhances the effective electron-electron correlation and strengthens the Mott phase...
July 14, 2017: Physical Review Letters
W P Cai, Z R Yan, R M Liu, M H Qin, M Zeng, X B Lu, X S Gao, J-M Liu
Based on the modified Heisenberg-Kitaev model, the effects of magnetic substitution on the magnetic properties of the honeycomb-lattice iridate [Formula: see text] [Formula: see text] are studied using Monte Carlo simulations. It is observed that the long-range zigzag state of the original system is rather fragile and can be replaced by a spin-glass state even for small substitution, well consistent with the experimental observation in Ru-substituted samples (Mehlawat et al 2015 Phys. Rev. B 92 134412). Both the disordered Heisenberg and Kitaev interactions caused by the magnetic ion-doping are suggested to be responsible for the magnetic phase transitions in the system...
October 11, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Valentín Huerva, Francisco J Ascaso, Isabel Caral, Andrzej Grzybowski
BACKGROUND: To assess the constants and formula for aphakia correction with iris-claw IOLs to achieve the best refractive status in cases of late in-the-bag IOL complex dislocation. METHODS: A literature search was performed. The following data were obtained: Iris-claw IOL model, Iridal or retroiridal enclavation, A-constant, ultrasound or optical biometry, formula employed and refractive outcomes. Acceptable emmetropia was considered if the resulting spherical equivalent (SE) was within ±1...
July 11, 2017: BMC Ophthalmology
Marzia Vergine, Alessio Aprile, Erika Sabella, Alessandra Genga, Maria Siciliano, Patrizia Rampino, Marcello Salvatore Lenucci, Andrea Luvisi, Luigi De Bellis
Heavy metal excess in soil represents a critical problem for crop productivity. Among these pollutants, cadmium (Cd) is one of the most dangerous in terms of food-chain contamination. Two durum wheat near-isogenic lines (NILs) and 12 commercial varieties (cultivars Arcangelo, Aureo, Aziziah, Cappelli, Cirillo, Creso, Iride, Maestrale, Parsifal, Russello, Strongfield, and Svevo) of durum wheat were exposed to a nontoxic level of Cd to evaluate its concentration in grains, roots, and shoots, as well as effects on biomass production...
August 2, 2017: Journal of Agricultural and Food Chemistry
Touka Banaee, Mohammad-Reza Ansari-Astaneh, Hamidreza Pourreza, Fatemeh Faal Hosseini, Maryam Vatanparast, Nasser Shoeibi, Vajihe Jami
PURPOSE: To compare the quality of fundus photographs taken before and after instillation of one drop of tropicamide. METHODS: The 45º fundus photographs were taken with a non-mydriatic fundus camera in three conditions of the pupil; pre-mydriatic, 10 minutes after one drop of tropicamide, and fully dilated. Two photographs were taken in each condition; one centered on the macula and the other on the optic disc. Two vitreoretinal specialists graded the images. RESULTS: A total of 1768 fundus photographs of 149 diabetic patients with dark irides were included...
August 2017: Ophthalmic Epidemiology
Marie H Solheim, Allen C Clermont, Jonathon N Winnay, Erlend Hallstensen, Anders Molven, Pål R Njølstad, Eyvind Rødahl, C Ronald Kahn
Purpose: To determine the ocular consequences of a dominant-negative mutation in the p85α subunit of phosphatidylinositol 3-kinase (PIK3R1) using a knock-in mouse model of SHORT syndrome, a syndrome associated with short stature, lipodystrophy, diabetes, and Rieger anomaly in humans. Methods: We investigated knock-in mice heterozygous for the SHORT syndrome mutation changing arginine 649 to tryptophan in p85α (PIK3R1) using physical examination, optical coherence tomography (OCT), tonometry, and histopathologic sections from paraffin-embedded eyes, and compared the findings to similar investigations in two human subjects with SHORT syndrome heterozygous for the same mutation...
June 1, 2017: Investigative Ophthalmology & Visual Science
Kentaro Ueda, Taekoo Oh, Bohm-Jung Yang, Ryoma Kaneko, Jun Fujioka, Naoto Nagaosa, Yoshinori Tokura
The interplay between electron correlation and spin-orbit coupling in solids has been proven to be an abundant gold mine for emergent topological phases. Here we report the results of systematic magnetotransport study on bandwidth-controlled pyrochlore iridates R2Ir2O7 near quantum metal-insulator transition (MIT). The application of a magnetic field along [001] crystallographic direction (H//[001]) significantly decreases resistivity while producing a unique Hall response, which indicates the emergence of the novel semi-metallic state in the course of the magnetic transformation from all-in all-out (AIAO, 4/0) to 2-in 2-out (2/2) spin configuration...
May 24, 2017: Nature Communications
Pontus Laurell, Gregory A Fiete
We theoretically study the magnetic properties of pyrochlore iridate bilayer and trilayer thin films grown along the [111] direction using a strong coupling approach. We find the ground state magnetic configurations on a mean field level and carry out a spin-wave analysis about them. In the trilayer case the ground state is found to be the all-in-all-out (AIAO) state, whereas the bilayer has a deformed AIAO state. For all parameters of the spin-orbit coupled Hamiltonian we study, the lowest magnon band in the trilayer case has a nonzero Chern number...
April 28, 2017: Physical Review Letters
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