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Brown A, Greenwood J, Lockhart de la Rosa CJ, Rodríguez González MC, Verguts K, Brems S, Zhang H, Hirsch BE, De Gendt S, Delabie A, Caymax M, Teyssandier J, De Feyter S. A chemisorbed interfacial layer for seeding atomic layer deposition on graphite. Nanoscale 2021; 13:12327-12341. [PMID: 34254598 DOI: 10.1039/d0nr06959k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The integration of graphene, and more broadly two-dimensional materials, into devices and hybrid materials often requires the deposition of thin films on their usually inert surface. As a result, strategies for the introduction of surface reactive sites have been developed but currently pose a dilemma between robustness and preservation of the graphene properties. A method is reported here for covalently modifying graphitic surfaces, introducing functional groups that act as reactive sites for the growth of high quality dielectric layers. Aryl diazonium species containing tri-methoxy groups are covalently bonded (grafted) to highly oriented pyrolytic graphite (HOPG) and graphene, acting as seeding species for atomic layer deposition (ALD) of Al2O3, a high-κ dielectric material. A smooth and uniform dielectric film growth is confirmed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrical measurements. Raman spectroscopy showed that the aryl groups gradually detach from the graphitic surface during the Al2O3 ALD process at 150 °C, with the surface reverting back to the original sp2-hybridized state and without damaging the dielectric layer. Thus, the grafted aryl groups can act as a sacrificial seeding layer after healing the defects of the graphitic surface with annealing treatment.
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Affiliation(s)
- Anton Brown
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven-University of Leuven, Celestijnenlaan, 200 F, 3001 Leuven, Belgium.
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2
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Bragança AM, Minoia A, Steeno R, Seibel J, Hirsch BE, Verstraete L, Ivasenko O, Müllen K, Mali KS, Lazzaroni R, De Feyter S. Detection and Stabilization of a Previously Unknown Two-Dimensional (Pseudo)polymorph using Lateral Nanoconfinement. J Am Chem Soc 2021; 143:11080-11087. [PMID: 34283574 DOI: 10.1021/jacs.1c04445] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report on the detection and stabilization of a previously unknown two-dimensional (2D) pseudopolymorph of an alkoxy isophthalic acid using lateral nanoconfinement. The self-assembled molecular networks formed by the isophthalic acid derivative were studied at the interface between covalently modified graphite and an organic solvent. When self-assembled on graphite with moderate surface coverage of covalently bound aryl groups, a previously unknown metastable pseudopolymorph was detected. This pseudopolymorph, which was presumably "trapped" in between the surface bound aryl groups, underwent a time-dependent phase transition to the stable polymorph typically observed on pristine graphite. The stabilization of the pseudopolymorph was then achieved by using an alternative nanoconfinement strategy, where the domains of the pseudopolymorph could be formed and stabilized by restricting the self-assembly in nanometer-sized shallow compartments produced by STM-based nanolithography carried out on a graphite surface with a high density of covalently bound aryl groups. These experimental results are supported by molecular mechanics and molecular dynamics simulations, which not only provide important insight into the relative stabilities of the different structures, but also shed light onto the mechanism of the formation and stabilization of the pseudopolymorph under nanoscopic lateral confinement.
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Affiliation(s)
- Ana M Bragança
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Andrea Minoia
- Laboratory for Chemistry of Novel Materials, Materials Research Institute, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Roelof Steeno
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Johannes Seibel
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Brandon E Hirsch
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Lander Verstraete
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Oleksandr Ivasenko
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Kunal S Mali
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Roberto Lazzaroni
- Laboratory for Chemistry of Novel Materials, Materials Research Institute, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Steven De Feyter
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
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3
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Tahara K, Kubo Y, Hashimoto S, Ishikawa T, Kaneko H, Brown A, Hirsch BE, Feyter SD, Tobe Y. Porous Self-Assembled Molecular Networks as Templates for Chiral-Position-Controlled Chemical Functionalization of Graphitic Surfaces. J Am Chem Soc 2020; 142:7699-7708. [DOI: 10.1021/jacs.0c02979] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Kazukuni Tahara
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Yuki Kubo
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Shingo Hashimoto
- Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Toru Ishikawa
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hiromasa Kaneko
- Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Anton Brown
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Brandon E. Hirsch
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Steven De Feyter
- Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Yoshito Tobe
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
- Department of Applied Chemistry, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
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4
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Phan TH, Van Gorp H, Li Z, Trung Huynh TM, Fujita Y, Verstraete L, Eyley S, Thielemans W, Uji-I H, Hirsch BE, Mertens SFL, Greenwood J, Ivasenko O, De Feyter S. Graphite and Graphene Fairy Circles: A Bottom-Up Approach for the Formation of Nanocorrals. ACS Nano 2019; 13:5559-5571. [PMID: 31013051 DOI: 10.1021/acsnano.9b00439] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A convenient covalent functionalization approach and nanopatterning method of graphite and graphene is developed. In contrast to expectations, electrochemically activated dediazotization of a mixture of two aryl diazonium compounds in aqueous media leads to a spatially inhomogeneous functionalization of graphitic surfaces, creating covalently modified surfaces with quasi-uniform spaced islands of pristine graphite or graphene, coined nanocorrals. Cyclic voltammetry and chronoamperometry approaches are compared. The average diameter (45-130 nm) and surface density (20-125 corrals/μm2) of these nanocorrals are tunable. These chemically modified nanostructured graphitic (CMNG) surfaces are characterized by atomic force microscopy, scanning tunneling microscopy, Raman spectroscopy and microscopy, and X-ray photoelectron spectroscopy. Mechanisms leading to the formation of these CMNG surfaces are discussed. The potential of these surfaces to investigate supramolecular self-assembly and on-surface reactions under nanoconfinement conditions is demonstrated.
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Affiliation(s)
- Thanh Hai Phan
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
- Department of Physics , Quy Nhon University , 170 An Duong Vuong , Quy Nhon , Vietnam
| | - Hans Van Gorp
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Zhi Li
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Thi Mien Trung Huynh
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
- Department of Chemistry , Quy Nhon University , 170 An Duong Vuong , Quy Nhon , Vietnam
| | - Yasuhiko Fujita
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Lander Verstraete
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Samuel Eyley
- Department of Chemical Engineering, Renewable Materials and Nanotechnology Group, Campus Kortrijk , KU Leuven , Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
| | - Wim Thielemans
- Department of Chemical Engineering, Renewable Materials and Nanotechnology Group, Campus Kortrijk , KU Leuven , Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
| | - Hiroshi Uji-I
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Brandon E Hirsch
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Stijn F L Mertens
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
- Department of Chemistry , Lancaster University , Lancaster LA1 4YB , United Kingdom
| | - John Greenwood
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Oleksandr Ivasenko
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
| | - Steven De Feyter
- Department of Chemistry, Division of Molecular Imaging and Photonics , KU Leuven , Celestijnenlaan 200F , B-3001 Leuven , Belgium
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5
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Hu Y, Bragança AM, Verstraete L, Ivasenko O, Hirsch BE, Tahara K, Tobe Y, De Feyter S. Phase selectivity triggered by nanoconfinement: the impact of corral dimensions. Chem Commun (Camb) 2019; 55:2226-2229. [DOI: 10.1039/c8cc08602h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Phase behavior of self-assembled molecular networks is affected by spatial confinement in corrals.
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Affiliation(s)
- Yi Hu
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Ana M. Bragança
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Lander Verstraete
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Oleksandr Ivasenko
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Brandon E. Hirsch
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Kazukuni Tahara
- Department of Applied Chemistry
- School of Science and Technology
- Meiji University
- Tama-ku
- Japan
| | - Yoshito Tobe
- Department of Applied Chemistry
- School of Science and Technology
- Meiji University
- Tama-ku
- Japan
| | - Steven De Feyter
- Department of Chemistry
- Division of Molecular Imaging and Photonics
- KU Leuven
- B-3001 Leuven
- Belgium
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6
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Tahara K, Ishikawa T, Hirsch BE, Kubo Y, Brown A, Eyley S, Daukiya L, Thielemans W, Li Z, Walke P, Hirose S, Hashimoto S, De Feyter S, Tobe Y. Self-Assembled Monolayers as Templates for Linearly Nanopatterned Covalent Chemical Functionalization of Graphite and Graphene Surfaces. ACS Nano 2018; 12:11520-11528. [PMID: 30387985 DOI: 10.1021/acsnano.8b06681] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An approach for nanoscale covalent functionalization of graphite surfaces employing self-assembled molecular monolayers of n-alkanes as templating masks is presented. Linearly aligned aryl groups with a lateral periodicity of 5 or 7 nm are demonstrated utilizing molecular templates of different lengths. The key feature of this approach is the use of a phase separated solution double layer consisting of a thin organic layer containing template molecules topped by an aqueous layer containing aryldiazonium molecules capable of electrochemical reduction to generate aryl radicals which bring about surface grafting. Upon sweeping of the potential, lateral displacement dynamics at the n-alkane terminal edges acts in conjunction with electrochemical diffusion to result in templated covalent bond formation in a linear fashion. This protocol was demonstrated to be applicable to linear grafting of graphene. The present processing described herein is useful for the realization of rationally designed nanoscale materials.
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Affiliation(s)
- Kazukuni Tahara
- Division of Frontier Materials Science, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
- Department of Applied Chemistry, School of Science and Technology , Meiji University , 1-1-1 Higashimita, Tama-ku , Kawasaki , Kanagawa 214-8571 , Japan
- PRESTO, Japan Science and Technology Agency , 4-1-8, Honcho , Kawaguchi , Saitama 332-0012 , Japan
| | - Toru Ishikawa
- Division of Frontier Materials Science, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
| | - Brandon E Hirsch
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Yuki Kubo
- Division of Frontier Materials Science, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
| | - Anton Brown
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Samuel Eyley
- Renewable Materials and Nanotechnology Group, Department of Chemical Engineering , KU Leuven, Campus Kortrijk , Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
| | - Lakshya Daukiya
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Wim Thielemans
- Renewable Materials and Nanotechnology Group, Department of Chemical Engineering , KU Leuven, Campus Kortrijk , Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
| | - Zhi Li
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Peter Walke
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Shingo Hirose
- Department of Applied Chemistry, School of Science and Technology , Meiji University , 1-1-1 Higashimita, Tama-ku , Kawasaki , Kanagawa 214-8571 , Japan
| | - Shingo Hashimoto
- Department of Applied Chemistry, School of Science and Technology , Meiji University , 1-1-1 Higashimita, Tama-ku , Kawasaki , Kanagawa 214-8571 , Japan
| | - Steven De Feyter
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , 3001 Leuven , Belgium
| | - Yoshito Tobe
- Division of Frontier Materials Science, Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
- The Institute of Scientific and Industrial Research , Osaka University , Ibaraki , Osaka 567-0047 , Japan
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7
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Verstraete L, Smart J, Hirsch BE, De Feyter S. Unidirectional supramolecular self-assembly inside nanocorrals via in situ STM nanoshaving. Phys Chem Chem Phys 2018; 20:27482-27489. [PMID: 30358776 DOI: 10.1039/c8cp05316b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembly of an alkylated diacetylene derivative is spatially confined via in situ scanning tunneling microscopy (STM) nanoshaving inside covalently modified highly ordered pyrolytic graphite (CM-HOPG). In contrast to unconstrained self-assembly that occurs randomly along three thermodynamically equivalent surface lattice directions, spatially confined assemblies are shown to form along chosen substrate orientations. Experimental statistics suggest two mechanisms for breaking the rotational degeneracy of the surface. First, the assembly orientation is biased via lateral confinement inside nanocorrals that do not match the substrate symmetry. Second, an interaction between the assembling molecules and the STM tip during nanoshaving guides 2D crystal nucleation and growth. The results presented here open new possibilities to regulate and orient self-assembled architectures via in situ nanomechanical manipulation techniques and provide mechanistic insights into the process.
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Affiliation(s)
- Lander Verstraete
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven-University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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8
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Seibel J, Verstraete L, Hirsch BE, Bragança AM, De Feyter S. Biasing Enantiomorph Formation via Geometric Confinement: Nanocorrals for Chiral Induction at the Liquid–Solid Interface. J Am Chem Soc 2018; 140:11565-11568. [DOI: 10.1021/jacs.8b04992] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Johannes Seibel
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Lander Verstraete
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Brandon E. Hirsch
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Ana M. Bragança
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Steven De Feyter
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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9
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Van Gorp H, Walke P, Bragança AM, Greenwood J, Ivasenko O, Hirsch BE, De Feyter S. Self-Assembled Polystyrene Beads for Templated Covalent Functionalization of Graphitic Substrates Using Diazonium Chemistry. ACS Appl Mater Interfaces 2018; 10:12005-12012. [PMID: 29485850 DOI: 10.1021/acsami.7b18969] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A network of self-assembled polystyrene beads was employed as a lithographic mask during covalent functionalization reactions on graphitic surfaces to create nanocorrals for confined molecular self-assembly studies. The beads were initially assembled into hexagonal arrays at the air-liquid interface and then transferred to the substrate surface. Subsequent electrochemical grafting reactions involving aryl diazonium molecules created covalently bound molecular units that were localized in the void space between the nanospheres. Removal of the bead template exposed hexagonally arranged circular nanocorrals separated by regions of chemisorbed molecules. Small molecule self-assembly was then investigated inside the resultant nanocorrals using scanning tunneling microscopy to highlight localized confinement effects. Overall, this work illustrates the utility of self-assembly principles to transcend length scale gaps in the development of hierarchically patterned molecular materials.
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Affiliation(s)
- Hans Van Gorp
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - Peter Walke
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - Ana M Bragança
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - John Greenwood
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - Oleksandr Ivasenko
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - Brandon E Hirsch
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
| | - Steven De Feyter
- Division of Molecular Imaging and Photonics, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B3001 Leuven , Belgium
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10
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Verstraete L, Hirsch BE, Greenwood J, De Feyter S. Confined polydiacetylene polymerization reactions for programmed length control. Chem Commun (Camb) 2018; 53:4207-4210. [PMID: 28287236 DOI: 10.1039/c7cc00885f] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Polydiacetylene polymers of defined lengths are formed from self-assembled precursors inside nanocorrals created within grafted graphite substrates. A scanning tunneling microscope tip is used to nanoshave corrals at the liquid-solid interface allowing orientationally controlled supramolecular self-assembly of linear diacetylene molecules. Electrical pulses trigger topological one-dimensional polymerization reactions that are confined by the nanocorral template dimensions.
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Affiliation(s)
- Lander Verstraete
- Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven - University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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11
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Castillo HD, Espinosa-Duran JM, Dobscha JR, Ashley DC, Debnath S, Hirsch BE, Schrecke SR, Baik MH, Ortoleva PJ, Raghavachari K, Flood AH, Tait SL. Amphiphile self-assembly dynamics at the solution-solid interface reveal asymmetry in head/tail desorption. Chem Commun (Camb) 2018; 54:10076-10079. [DOI: 10.1039/c8cc04465a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Asymmetric dynamics in fundamental adsorption and desorption steps drive self-assembly at solution/solid interface.
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Affiliation(s)
| | | | | | | | | | | | | | - Mu-Hyun Baik
- Department of Chemistry
- Indiana University
- Bloomington
- USA
| | | | | | - Amar H. Flood
- Department of Chemistry
- Indiana University
- Bloomington
- USA
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12
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Samperi M, Hirsch BE, Diaz Fernandez YA. Exploring the science of thinking independently together: Faraday Discussion Volume 204 - Complex Molecular Surfaces and Interfaces, Sheffield, UK, July 2017. Chem Commun (Camb) 2017; 53:12601-12607. [PMID: 29139496 DOI: 10.1039/c7cc90389h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 2017 Faraday Discussion on Complex Molecular Surfaces and Interfaces brought together theoreticians and experimentalists from both physical and chemical backgrounds to discuss the relevant applied and fundamental research topics within the broader field of chemical surface analysis and characterization. Main discussion topics from the meeting included the importance of "disordered" two-dimensional (2D) molecular structures and the utility of kinetically trapped states. An emerging need for new experimental tools to address dynamics and kinetic pathways involved in self-assembled systems, as well as the future prospects and current limitations of in silico studies were also discussed. The following article provides a brief overview of the work presented and the challenges discussed during the meeting.
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Affiliation(s)
- M Samperi
- GSK Carbon Neutral Laboratories for Sustainable Chemistry, The University of Nottingham, Triumph Road, NG7 2TU, UK.
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13
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Qiao B, Hirsch BE, Lee S, Pink M, Chen CH, Laursen BW, Flood AH. Ion-Pair Oligomerization of Chromogenic Triangulenium Cations with Cyanostar-Modified Anions That Controls Emission in Hierarchical Materials. J Am Chem Soc 2017; 139:6226-6233. [DOI: 10.1021/jacs.7b01937] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Bo Qiao
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Brandon E. Hirsch
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Semin Lee
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Maren Pink
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Chun-Hsing Chen
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Bo W. Laursen
- Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, København Ø 2100, Denmark
| | - Amar H. Flood
- Department
of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
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14
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Hirsch BE, McDonald KP, Tait SL, Flood AH. Physical and chemical model of ion stability and movement within the dynamic and voltage-gated STM tip–surface tunneling junction. Faraday Discuss 2017; 204:159-172. [DOI: 10.1039/c7fd00104e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The interaction and mobility of ions in complex systems are fundamental to processes throughout chemistry, biology, and physics. However, nanoscale characterization of ion stability and migration remains poorly understood. Here, we examine ion movements to and from physisorbed molecular receptors at solution–graphite interfaces by developing a theoretical model alongside experimental scanning tunneling microscopy (STM) results. The model includes van der Waals forces and electrostatic interactions originating from the surface, tip, and physisorbed receptors, as well as a tip–surface electric field arising from the STM bias voltage (Vb). Our model reveals how both the electric field and tip–surface distance, dtip, can influence anion stability at the receptor binding sites on the surface or at the STM tip, as well as the size of the barrier for anion transitions between those locations. These predictions agree well with prior and new STM results from the interactions of anions with aryl-triazole receptors that order into functional monolayers on graphite. Scanning produces clear resolution at large magnitude negative surface biases (−0.8 V) while resolution degrades at small negative surface biases (−0.4 V). The loss in resolution arises from frequent tip retractions assigned to anion migration within the tip–surface tunneling region. This experimental evidence in combination with support from the model demonstrates a local voltage gating of anions with the STM tip inside physisorbed receptors. This generalized model and experimental evidence may help to provide a basis to understand the nanoscale details of related chemical transformations and their underlying thermodynamic and kinetic preferences.
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Affiliation(s)
| | | | | | - Amar H. Flood
- Department of Chemistry
- Indiana University
- Bloomington
- USA
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15
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Verstraete L, Greenwood J, Hirsch BE, De Feyter S. Self-Assembly under Confinement: Nanocorrals for Understanding Fundamentals of 2D Crystallization. ACS Nano 2016; 10:10706-10715. [PMID: 27749033 PMCID: PMC5198256 DOI: 10.1021/acsnano.6b05954] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 10/11/2016] [Indexed: 05/30/2023]
Abstract
Nanocorrals with different size, shape, and orientation are created on covalently modified highly oriented pyrolytic graphite surfaces using scanning probe nanolithography, i.e., nanoshaving. Alkylated diacetylene molecules undergo laterally confined supramolecular self-assembly within these corrals. When nanoshaving is performed in situ, at the liquid-solid interface, the orientation of the supramolecular lamellae structure is directionally influenced by the gradual graphite surface exposure. Careful choice of the nanoshaving direction with respect to the substrate symmetry axes promotes alignment of the supramolecular lamellae within the corral. Self-assembly occurring inside corrals of different size and shape reveals the importance of geometric and kinetic constraints controlled by the nanoshaving process. Finally, seed-mediated crystallization studies demonstrate confinement control over nucleation and growth principles.
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Lee S, Hirsch BE, Liu Y, Dobscha JR, Burke DW, Tait SL, Flood AH. Back Cover: Multifunctional Tricarbazolo Triazolophane Macrocycles: One-Pot Preparation, Anion Binding, and Hierarchical Self-Organization of Multilayers (Chem. Eur. J. 2/2016). Chemistry 2016. [DOI: 10.1002/chem.201504865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Hirsch BE, McDonald KP, Flood AH, Tait SL. Living on the edge: Tuning supramolecular interactions to design two-dimensional organic crystals near the boundary of two stable structural phases. J Chem Phys 2015; 142:101914. [PMID: 25770503 DOI: 10.1063/1.4906895] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
One of the benefits of supramolecular assemblies that form at dynamic interfaces is the opportunity to develop condensed phase systems that respond to environmental stimuli. A prerequisite of this responsive behavior is that the supramolecular system be designed to sit very near the stability of two or more crystal structures. We have created such a bi-phasic system with aryl-triazole oligomers by investigating how phase morphology is controlled by the interplay between interactions that involve the oligomer's dipolar cores (Δμ = 3.5 debye), van der Waals contacts of their pendant alkyl chains (C4-C18), and close-contact hydrogen bonding. Scanning tunneling microscopy experiments conducted at the solution-graphite interface allow sub-molecular resolution of the ordered monolayers to unambiguously determine the packing and structure of two principle phases, α and β. The system is balanced very near the edge of phase stability, evidenced by co-existent phases present over short time frames and by the changes in preference between the two 2D supramolecular assemblies that occur with small modifications to the molecular structure. We demonstrate that the bi-phasic behavior can be understood as a balance between electrostatic interactions and van der Waals contacts, two variables within a larger parameter space, allowing synthetic design to move this solution-surface system across the stability boundary of different condensed-phase structures. These findings are a foundation for the development of environmentally responsive 2D supramolecular arrays.
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Affiliation(s)
- Brandon E Hirsch
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, USA
| | - Kevin P McDonald
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, USA
| | - Amar H Flood
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, USA
| | - Steven L Tait
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405, USA
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Lee S, Hirsch BE, Liu Y, Dobscha JR, Burke DW, Tait SL, Flood AH. Multifunctional Tricarbazolo Triazolophane Macrocycles: One-Pot Preparation, Anion Binding, and Hierarchical Self-Organization of Multilayers. Chemistry 2015; 22:560-9. [PMID: 26593327 DOI: 10.1002/chem.201503161] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 01/23/2023]
Abstract
Programming the synthesis and self-assembly of molecules is a compelling strategy for the bottom-up fabrication of ordered materials. To this end, shape-persistent macrocycles were designed with alternating carbazoles and triazoles to program a one-pot synthesis and to bind large anions. The macrocycles bind anions that were once considered too weak to be coordinated, such as PF6 (-) , with surprisingly high affinities (β2 =10(11) M(-2) in 80:20 chloroform/methanol) and positive cooperativity, α=(4 K2 /K1 )=1200. We also discovered that the macrocycles assemble into ultrathin films of hierarchically ordered tubes on graphite surfaces. The remarkable surface-templated self-assembly properties, as was observed by using scanning tunneling microscopy, are attributed to the complementary pairing of alternating triazoles and carbazoles inscribed into both the co-facial and edge-sharing seams that exist between shape-persistent macrocycles. The multilayer assembly is also consistent with the high degree of molecular self-association observed in solution, with self-association constants of K=300 000 M(-1) (chloroform/methanol 80:20). Scanning tunneling microscopy data also showed that surface assemblies readily sequester iodide anions from solution, modulating their assembly. This multifunctional macrocycle provides a foundation for materials composed of hierarchically organized and nanotubular self-assemblies.
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Affiliation(s)
- Semin Lee
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA).,Current Address: Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N Mathews Ave, Urbana, IL 61801 (USA)
| | - Brandon E Hirsch
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - Yun Liu
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - James R Dobscha
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - David W Burke
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - Steven L Tait
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
| | - Amar H Flood
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405 (USA)
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Hirsch BE, McDonald KP, Qiao B, Flood AH, Tait SL. Selective anion-induced crystal switching and binding in surface monolayers modulated by electric fields from scanning probes. ACS Nano 2014; 8:10858-10869. [PMID: 25257197 DOI: 10.1021/nn504685t] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Anion-selective (Br(-) and I(-)) and voltage-driven crystal switching between two differently packed phases (α ⇆ β) was observed in 2D crystalline monolayers of aryl-triazole receptors ordered at solution-graphite interfaces. Addition of Br(-) and I(-) was found to stimulate the α → β phase transformation and to produce ion binding to the β phase assembly, while Cl(-) and BF4(-) addition retained the α phase. Unlike all other surface assemblies of either charged molecules or ion-templated 2D crystallization of metal-ligand or receptor-based adsorbates, the polarity of the electric field between the localized scanning tip and the graphite substrate was found to correlate with phase switching: β → α is driven at -1.5 V, while α → β occurs at +1.1 V. Ion-pairing between the countercations and the guest anions was also observed. These observations are supported by control studies including variation of anion species, relative anion concentration, surface temperature, tip voltage, and scanning time.
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Affiliation(s)
- Brandon E Hirsch
- Department of Chemistry, Indiana University , 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Hirsch BE, Lee S, Qiao B, Chen CH, McDonald KP, Tait SL, Flood AH. Anion-induced dimerization of 5-fold symmetric cyanostars in 3D crystalline solids and 2D self-assembled crystals. Chem Commun (Camb) 2014; 50:9827-30. [DOI: 10.1039/c4cc03725a] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jaumard NV, Udupa JK, Siegler S, Schuster JM, Hilibrand AS, Hirsch BE, Borthakur A, Winkelstein BA. Three-dimensional kinematic stress magnetic resonance image analysis shows promise for detecting altered anatomical relationships of tissues in the cervical spine associated with painful radiculopathy. Med Hypotheses 2013; 81:738-44. [PMID: 23942030 DOI: 10.1016/j.mehy.2013.07.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 07/20/2013] [Indexed: 10/26/2022]
Abstract
For some patients with radiculopathy a source of nerve root compression cannot be identified despite positive electromyography (EMG) evidence. This discrepancy hampers the effective clinical management for these individuals. Although it has been well-established that tissues in the cervical spine move in a three-dimensional (3D) manner, the 3D motions of the neural elements and their relationship to the bones surrounding them are largely unknown even for asymptomatic normal subjects. We hypothesize that abnormal mechanical loading of cervical nerve roots during pain-provoking head positioning may be responsible for radicular pain in those cases in which there is no evidence of nerve root compression on conventional cervical magnetic resonance imaging (MRI) with the neck in the neutral position. This biomechanical imaging proof-of-concept study focused on quantitatively defining the architectural relationships between the neural and bony structures in the cervical spine using measurements derived from 3D MR images acquired in neutral and pain-provoking neck positions for subjects: (1) with radicular symptoms and evidence of root compression by conventional MRI and positive EMG, (2) with radicular symptoms and no evidence of root compression by MRI but positive EMG, and (3) asymptomatic age-matched controls. Function and pain scores were measured, along with neck range of motion, for all subjects. MR imaging was performed in both a neutral position and a pain-provoking position. Anatomical architectural data derived from analysis of the 3D MR images were compared between symptomatic and asymptomatic groups, and the symptomatic groups with and without imaging evidence of root compression. Several differences in the architectural relationships between the bone and neural tissues were identified between the asymptomatic and symptomatic groups. In addition, changes in architectural relationships were also detected between the symptomatic groups with and without imaging evidence of nerve root compression. As demonstrated in the data and a case study the 3D stress MR imaging approach provides utility to identify biomechanical relationships between hard and soft tissues that are otherwise undetected by standard clinical imaging methods. This technique offers a promising approach to detect the source of radiculopathy to inform clinical management for this pathology.
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Affiliation(s)
- N V Jaumard
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States; Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, United States
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Whetstone J, Branstetter BF, Hirsch BE. Fluoroscopic and CT fistulography of the first branchial cleft. AJNR Am J Neuroradiol 2006; 27:1817-9. [PMID: 17032848 PMCID: PMC7977877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We present an unusual case of a complete first branchial cleft fistula communicating between the external auditory canal and the skin near the angle of the mandible. CT and fluoroscopic fistulography were used to establish the presence and course of the tract and to assist in surgical planning. The embryology and classification of first branchial cleft anomalies are discussed, with emphasis on the impact of imaging.
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Affiliation(s)
- J Whetstone
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Ringleb SI, Udupa JK, Siegler S, Imhauser CW, Hirsch BE, Liu J, Odhner D, Okereke E, Roach N. The effect of ankle ligament damage and surgical reconstructions on the mechanics of the ankle and subtalar joints revealed by three-dimensional stress MRI. J Orthop Res 2005; 23:743-9. [PMID: 16022985 DOI: 10.1016/j.orthres.2005.02.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 01/27/2005] [Accepted: 01/27/2005] [Indexed: 02/04/2023]
Abstract
Common image-based diagnostic techniques used to detect ankle ligament injuries or the effects of those injuries (e.g., mechanical instability) include magnetic resonance imaging (MRI) and stress radiography. Each of these techniques has limitations. The interpretation of the results obtained through stress radiography, a two-dimensional technique, is highly controversial. MRI can facilitate visualization of soft tissue, but three-dimensional visualization of the full length of the ligaments or detecting partial ligament damage is difficult. This work is part of a long-term study aimed at improving the diagnostic ability of MRI by utilizing it not only to visualize the ligaments but also to detect the mechanical instability produced at the ankle and subtalar joints due to ligament damage. The goal of the present study was to evaluate the ability of a previously developed technique called 3D stress MRI (sMRI) to detect in vitro the effect of damage to the lateral collateral ligaments and the stabilizing effect produced by two common surgical reconstruction techniques. MRI data were collected from eight cadaver limbs in a MR compatible ankle-loading device in neutral, inversion, and anterior drawer. Each specimen was tested intact, after cutting the anterior talo-fibular ligament followed by the calcaneo-fibular ligament and after applying two reconstructions. Ligament injuries produced significant changes in the response of the ankle and subtalar joints to load as detected by the 3D stress MRI technique. Both surgical procedures restored mechanical stability to the joints but they differed in the amount and type of stabilization achieved. We concluded that 3D sMRI can extend the diagnostic power of MRI from the current practice of slice-by-slice visualization to the assessment of mechanical function, the compromise in this function due to injury, and the effects of surgery.
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Affiliation(s)
- S I Ringleb
- Department of Mechanical Engineering and Mechanics, Drexel University, 32nd and Chestnut Streets, Philadelphia, PA 19104, USA
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Siegler S, Udupa JK, Ringleb SI, Imhauser CW, Hirsch BE, Odhner D, Saha PK, Okereke E, Roach N. Mechanics of the ankle and subtalar joints revealed through a 3D quasi-static stress MRI technique. J Biomech 2005; 38:567-78. [PMID: 15652556 DOI: 10.1016/j.jbiomech.2004.03.036] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2004] [Indexed: 10/26/2022]
Abstract
A technique to study the three-dimensional (3D) mechanical characteristics of the ankle and of the subtalar joints in vivo and in vitro is described. The technique uses an MR scanner compatible 3D positioning and loading linkage to load the hindfoot with precise loads while the foot is being scanned. 3D image processing algorithms are used to derive from the acquired MR images bone morphology, hindfoot architecture, and joint kinematics. The technique was employed to study these properties both in vitro and in vivo. The ankle and subtler joint motion and the changes in architecture produced in response to an inversion load and an anterior drawer load were evaluated. The technique was shown to provide reliable measures of bone morphology. The left-to-right variations in bone morphology were less than 5%. The left-to-right variations in unloaded hindfoot architecture parameters were less than 10%, and these properties were only slightly affected by inversion and anterior drawer loads. Inversion and anterior drawer loads produced motion both at the ankle and at the subtalar joint. In addition, high degree of coupling, primarily of internal rotation with inversion, was observed both at the ankle and at the subtalar joint. The in vitro motion produced in response to inversion and anterior drawer load was greater than the in vivo motion. Finally, external motion, measured directly across the ankle complex, produced in response to load was much greater than the bone movements measured through the 3D stress MRI technique indicating the significant effect of soft tissue and skin interference.
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Affiliation(s)
- S Siegler
- Department of Mechanical Engineering and Mechanics Drexel University 32nd and Chestnut Streets, Philadelphia, PA 19104, USA.
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25
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Hirsch BE. Umbilical cord blood transplants: legal considerations. J Nurs Law 2003; 3:21-6. [PMID: 12545978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- B E Hirsch
- Freeman & Jenner, P.C., Rockville, Maryland, USA
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Abstract
BACKGROUND The advent of cochlear implantation has revolutionized the options afforded to the deaf population. With the increase in the prevalence of this procedure have come larger experiences in the associated technical challenges and complications. RESULTS We present the evaluation and management of a patient with an unusual complication of improper placement of the implant electrode into the carotid canal and its management. We discuss the anatomy of the carotid artery and its proximity to the cochlea to emphasize the potential risk to this large vessel. CONCLUSIONS Damage to the carotid canal and the carotid artery is a potential risk of cochlear implant surgery. When available, we recommend intraoperative electrical testing of the cochlear implant be performed. If there is doubt as to the placement of the electrode, a radiograph should be obtained before the patient is taken out of the operating room to avoid this complication.
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Affiliation(s)
- B R Gastman
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania, USA
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Miura M, Sando I, Takasaki K, Haginomori S, Hirsch BE. Histopathologic study of temporal bone and eustachian tube in oculoauriculovertebral spectrum. Ann Otol Rhinol Laryngol 2001; 110:922-7. [PMID: 11642424 DOI: 10.1177/000348940111001006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bilateral temporal bone specimens from a 21-month-old girl and a left temporal bone-eustachian tube (ET) specimen from a full-term female newborn, both with oculoauriculovertebral spectrum, were studied histopathologically. The external and middle ears demonstrated severe anomalies, similar to those of previous reports describing the histopathologic findings of this syndrome. In addition, despite having a normal auricle, the 21-month-old child had bilateral hypoplastic cochleas as seen in Mondini dysplasia. The newborn had several anomalies of the ET, including a widely opened cartilaginous portion of the ET lumen and absence of the lateral lamina of the ET cartilage. We discuss the implications of the observed anomalies with regard to developmental and clinical issues.
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Affiliation(s)
- M Miura
- Division of Otopathology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA
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Abstract
Four temporal bone specimens, obtained from three individuals 1--6 years of age with Noonan syndrome (NS), were studied histopathologically. All four specimens were accompanied by similar inner ear abnormalities including the reduced number of spiral ganglion cells, enlarged lateral semicircular canal, and dislocated endolymphatic sac and vestibular aqueduct. The mean population of spiral ganglion cells (15,699 cells) was approximately half of those (32,978 cells) in four age-matched control cases. In addition, they had several middle ear abnormalities including the remaining mesenchyme and dehiscence of the facial canal. To our knowledge, this is the first report to describe the histopathological temporal bone findings in patients with NS. We discuss the implications of the observed abnormalities with regard to clinical issues.
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Affiliation(s)
- M Miura
- Division of Otopathology, Department of Otolaryngology, University of Pittsburgh School of Medicine, Suite 153, Eye and Ear Institute Building, 203 Lothrop Street, Pittsburgh, PA 15213, USA
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Affiliation(s)
- S Haginomori
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA
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Abstract
As mathematical models of the musculoskeletal system become increasingly detailed and precise, they require more accurate information about the architectural parameters of the individual muscles. These muscles are typically represented as Hill-type models, which require data on fiber length, physiological cross-sectional area (PCSA) and pennation angle. Most of this information for lower limb muscles has been published, except for data on the pennation angle of the intrinsic muscles of the foot. Each (n=20) intrinsic muscle of three human feet was dissected free. The dorsal and plantar surfaces were photographed and a digitized color image was imported into Abobe Photoshop. The muscles were divided into "anatomical units". For each anatomical unit (n=26), a line was drawn along the tendon axis and a number of other lines were drawn along individual muscle fibers. The angle between the tendon line and each fiber line was defined as the pennation angle of that fiber. By visual inspection, an effort was made to take measurements such that they represented the distribution of fibers in various parts of the muscle. Although some individual muscles had higher or lower pennation angles, when averaged for all specimens, the second dorsal interosseous had the smallest pennation angle (6.7+/-6.81 degrees) while the abductor digiti minimi had the largest (19.1+/-11.19 degrees). Since the cosines of the angles range from 0.9932 to 0.9449, the effect of the pennation angle on the force generated by the muscle was not great.
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Affiliation(s)
- W R Ledoux
- Rehabilitation Research and Development Center, V A Puget Sound Health Care System, Seattle, Washington 98108, USA
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Abstract
The purpose of this work is to characterize the three-dimensional (3-D) motion of the peritalar joint complex in vivo using magnetic resonance imaging (MRI). Each image data set utilized in this study is made of 60 longitudinal MR slices of the foot in each of eight positions from extreme pronation to extreme supination. We acquired and analyzed ten such data sets from normal subjects, seven data sets from pathological joints and two postoperative data sets. We segmented and formed the surfaces of the calcaneus, talus, cuboid and navicular from all data sets. About 30 geometrical parameters are computed for each joint in each position. The results present features of normal motion and show how normal and abnormal motion can be distinguished. They also show the consequences of surgery on the motion. This non- invasive method offers a unique tool to characterize and quantify the 3-D motion of the rearfoot in vivo from MR images.
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Affiliation(s)
- E Stindel
- Laboratoire de Traitement de l'Information Médicale Laboratoire d'anatomie, Centre Hospitalo-Universitaire de Brest, Université de Bretagne Occidentale, France
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Hirsch BE, Udupa JK, Stindel E. Tarsal joint kinematics via 3D imaging. Crit Rev Diagn Imaging 2000; 41:403-49. [PMID: 11193219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Lee SI, Klesmer J, Hirsch BE. Neuroleptic malignant syndrome associated with use of risperidone, ritonavir, and indinavir: a case report. Psychosomatics 2000; 41:453-4. [PMID: 11015640 DOI: 10.1176/appi.psy.41.5.453] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Takasaki K, Sando I, Hirsch BE. Loss of facial nerve fibers in a case of otosclerosis. Am J Otol 2000; 21:766-8. [PMID: 10993472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- K Takasaki
- Elizabeth McCullough Knowles Otopathology Laboratory, Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA
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Abstract
Tinnitus, a buzzing or ringing in the ear, may be pulsatile or continuous (nonpulsatile). The distinction, with a detailed clinical evaluation, determines the most appropriate imaging study. Pulsatile tinnitus suggests a vascular neoplasm, vascular anomaly, or vascular malformation. Most of the neoplasms are glomus tympanicum and glomus jugulare tumors. Vascular anomalies may cause pulsatile tinnitus, but the mechanism is unknown, and another (treatable) cause should be sought. Most neoplasms and anomalies are best seen on bone algorithm computed tomographic (CT) studies. Dural vascular malformations are often elusive on all cross-sectional imaging studies; conventional angiography may be necessary to make this diagnosis. Flow-sensitive magnetic resonance (MR) images show vascular loops compressing the eighth cranial nerve. Carotid dissections, aneurysms, atherosclerosis, and fibromuscular dysplasia can be identified on both MR imaging or MR angiographic studies and CT or CT angiographic studies. Otosclerosis and Paget disease are CT diagnoses. Benign intracranial hypertension often has no abnormal imaging findings. For patients with nonpulsatile tinnitus, MR imaging is the study of choice to exclude a vestibular schwannoma or other neoplasm of the cerebellopontine angle cistern. Multiple sclerosis and a Chiari I malformation are rare causes of pulsatile tinnitus, also best seen on MR studies. Many patients with tinnitus have no abnormal imaging findings.
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Affiliation(s)
- J L Weissman
- Department of Radiology and Otolaryngology, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Mail Code CR-135, Portland, OR 97201-3098, USA.
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Moody SA, Hirsch BE, Myers EN. Squamous cell carcinoma of the external auditory canal: an evaluation of a staging system. Am J Otol 2000; 21:582-8. [PMID: 10912706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVE The study was conducted to review a staging system proposed by the University of Pittsburgh for temporal bone cancer and to evaluate survival status according to stage, treatment, and certain prognostic factors. STUDY DESIGN The study was a retrospective case review. SETTING The study was conducted at a tertiary care medical center and specialty hospital. PATIENTS Thirty-two patients with primary squamous cell carcinoma of the external auditory canal were studied. INTERVENTION All patients underwent surgery of the temporal bone. Radiotherapy was given depending on tumor stage and histopathologic findings. MAIN OUTCOME MEASURES The 2-year survival rates of patients undergoing surgical resection with or without adjuvant radiotherapy. RESULTS The 2-year survival rates for primary squamous cell carcinoma of the temporal bone were as follows: T1 lesions 100%, T2 80%, T3 50%, and T4 7%. Survival for T3 tumors was 75% with postoperative radiotherapy, compared with 0% with surgery alone. CONCLUSIONS The 2-year survival data directly correlated with the staging system. The use of adjuvant radiotherapy increased survival rate in patients with a T3 lesion.
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Affiliation(s)
- S A Moody
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pennsylvania, USA
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Takasaki K, Hirsch BE, Sando I. Histopathologic study of the human eustachian tube and its surrounding structures following irradiation for carcinoma of the oropharynx. Arch Otolaryngol Head Neck Surg 2000; 126:543-6. [PMID: 10772313 DOI: 10.1001/archotol.126.4.543] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To describe a histopathologic analysis of a human temporal bone demonstrating patulous changes of the eustachian tube (ET) and its surrounding structures following radiation therapy. DESIGN Retrospective histopathologic case review and comparison with an age-matched control. SETTING Elizabeth McCullough Knowles Otopathology Laboratory, University of Pittsburgh School of Medicine, Pittsburgh, Pa. RESULTS A widened patulous ET was verified by demonstrating fibrous tissue replacement of the surrounding supporting structures related to the ET. The ET lumen was patulous and wider than the control case. Ostmann fatty tissue, the levator veli palatini muscle, and submucosal glands around the ET cartilage were replaced by dense connective tissue. CONCLUSION This is the first histopathologic report, to our knowledge, demonstrating the effects on the ET lumen and supporting structures following acute weight loss, possible tumor infiltration, and radiation changes for carcinoma of the oropharynx.
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Affiliation(s)
- K Takasaki
- Department of Otolaryngology, University of Pittsburgh School of Medicine, PA 15213, USA
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Affiliation(s)
- R C O'Reilly
- Mercy Hearing and Balance Center, Darby, PA, USA
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Stindel E, Udupa JK, Hirsch BE, Odhner D. A characterization of the geometric architecture of the peritalar joint complex via MRI: an aid to the classification of foot type. IEEE Trans Med Imaging 1999; 18:753-763. [PMID: 10571380 DOI: 10.1109/42.802753] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The purpose of this work is to study the architecture of the rearfoot using in vivo MR image data. Each data set used in this study is made of sixty sagittal slices of the foot acquired in a 1.5-T commercial GE MR system. We use the live-wire method to delineate boundaries and form the surfaces of the bones. In the first part of this work, we describe a new method to characterize the three-dimensional (3-D) relationships of four bones of the peritalar complex and apply this description technique to data sets from ten normal subjects and from seven pathological cases. In the second part, we propose a procedure to classify feet, based on the values of these new architectural parameters. We conclude that this noninvasive method offers a unique tool to characterize the 3-D architecture of the feet in live patients, based on a set of new architectural parameters. This can be integrated into a set of tools to improve diagnosis and treatment of foot malformations.
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Affiliation(s)
- E Stindel
- Laboratoire de Traitement de l'Information Médicale (EA 2218) Centre Hospitalo-Universitaire de Brest, Université de Bretagne Occidentale, France
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Buchman CA, Luxford WM, Hirsch BE, Fucci MJ, Kelly RH. Beta-2 transferrin assay in the identification of perilymph. Am J Otol 1999; 20:174-8. [PMID: 10100518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
HYPOTHESIS Western blot assay for beta-2 transferrin protein is a clinically useful method for the detection of human perilymph and should be used for the diagnosis of perilymph fistulas (PLFs). BACKGROUND Considerable controversy exists regarding the diagnosis of PLF. Recent studies suggest that the detection of beta-2 transferrin protein may be useful in the identification of perilymph. METHODS To evaluate the usefulness of the beta-2 transferrin assay for identifying human perilymph, paired perilymph samples and negative controls were collected on Gelfoam pledgets from 20 patients who had surgery that opened the inner ear. Blinded immunoelectrophoretic assay (Western blot) for beta-2 transferrin was performed on each specimen. RESULTS Only one (5%) of the known perilymph samples and none of the control specimens were definitely positive for beta-2 transferrin. Combined with historical data, this assay has 29% sensitivity, 100% specificity, 100% positive predictive value, and 31% negative predictive value. CONCLUSIONS These findings suggest that the beta-2 transferrin protein assay may not be a reliable method for detecting human perilymph when performed using this technique.
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Affiliation(s)
- C A Buchman
- Department of Otolaryngology, University of Miami School of Medicine, Florida, USA
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Stindel E, Udupa JK, Hirsch BE, Odhner D, Couture C. 3D MR image analysis of the morphology of the rear foot: application to classification of bones. Comput Med Imaging Graph 1999; 23:75-83. [PMID: 10227373 DOI: 10.1016/s0895-6111(98)00070-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The purpose of this work is to characterize the three-dimensional (3D) morphology of the bones of the rear foot using MR image data. It has two sub-aims: (i) to study the variability of the various computed architectural measures caused by the subjectivity and variations in the various processing operations; (ii) to study the morphology of the bones included in the peritalar complex. Each image data set utilized in this study consists of sixty sagittal slices of the foot acquired on a 1.5 T commercial GE MR system. The description of the rear foot morphology is based mainly on the principal axes, which represent the inertia axes of the bones, and on the bone surfaces. We use the live-wire method [Falcao AX, Udupa JK, Samarasekera S, Shoba S, Hirsch BE, Lotufo RA. User-steered image segmentation paradigms: live wire and live lane. Proceedings of the Society of Photo-optical Instrumentation Engineers 1996;2710:278-288] for segmenting and forming the surfaces of the bones. In the first part of this work, we focus on the analysis of the dependence of the principal axes system on segmentation and on scan orientation. In the second part, we describe the normal morphology of the rear foot considering the four bones namely calcaneus, cuboid, navicular, and talus, and compare this to a population from the upper Pleistocene. We conclude that this non-invasive method offers a unique tool to characterize the bone morphology in live patients towards the goal of understanding the architecture and kinematics of normal and pathological joints in vivo.
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Affiliation(s)
- E Stindel
- Department of Radiology, University of Pennsylvania, Philadelphia 19104-6021, USA
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Abstract
This paper describes a methodology for the analysis of three-dimensional (3-D) kinematics of live joints of the foot based on tomographic image data acquired via magnetic resonance (MR) imaging. A mechanical jig facilitates acquisition of MR images corresponding to different positions of the joint in a pronation-supination motion. The surfaces of the individual tarsal bones are constructed by segmenting the MR images. A mathematical description of the motion of the individual bones and of their relative motion is derived by computing the rigid transformation required to match the centroids and the principal axes of the surfaces. The mathematically described motion is animated via surface renditions of the bones. The kinematics of the bones are analyzed based on features extracted from the motion description and on how they vary with motion. Based on 17 joints that have been imaged, which includes an abnormal joint and the same joint after surgical correction, we conclude that this methodology offers a practical tool for measuring internal 3-D kinematics of joints in vivo and for characterizing and quantifying with specificity normal kinematics and their pathological deviations. Some of the 3-D kinematic animations generated using the methods of this paper for normal joints can be seen at: http:(/)/www.mipg.upenn.edu.
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Affiliation(s)
- J K Udupa
- Department of Radiology, University of Pennsylvania, Philadelphia 19104, USA.
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Weissman JL, Hirsch BE. Beyond the promontory: the multifocal origin of glomus tympanicum tumors. AJNR Am J Neuroradiol 1998; 19:119-22. [PMID: 9432168 PMCID: PMC8337344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE We examined other middle ear locations of glomus tympanicum tumors, which arise from glomus bodies accompanying the tympanic (Jacobson's) nerve through the middle ear. Most descriptions place these tumors on the promontory over the basal turn of the cochlea. METHODS We identified seven patients (all women) with small surgically confirmed glomus tympanicum tumors (not completely filling the middle ear) for whom CT scans were available for retrospective review. Patients' ages ranged from 23 to 78 years at the time of the high-resolution CT study (1.0- to 1.5-mm-thick sections). RESULTS All tumors arose on the medial wall of the middle ear. One was anterior to the promontory, beneath the cochleariform process and the semicanal of the tensor tympani. Two were inferior to the promontory, in the recess beneath the basal turn of the cochlea. Four were anteroinferior. None was actually on the apex of the promontory. CONCLUSION Glomus tympanicum tumors may arise in various locations on the medial wall of the middle ear, where Jacobson's nerve runs. The promontory is only one middle ear location in which glomus tympanicum tumors may arise. Familiarity with the course of the tympanic nerve helps tailor the search for, and facilitates accurate identification of, tiny glomus tympanicum tumors.
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Affiliation(s)
- J L Weissman
- Department of Radiology, University of Pittsburgh Medical Center, Pa 15213, USA
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Hirsch BE, Kamerer DB. Role of chemical labyrinthectomy in the treatment of Meniere's disease. Otolaryngol Clin North Am 1997; 30:1039-49. [PMID: 9386240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Medical management of Meniere's disease is successful in approximately 70% of patients. Surgical intervention is the treatment option when medication fails. Middle ear installation of aminoglycosides provides significant control of vertigo. This article addresses the role of aminoglycoside ablation of vestibular function in Meniere's disease.
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Affiliation(s)
- B E Hirsch
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Weissman JL, Hirsch BE, Fukui MB, Rudy TE. The evolving MR appearance of structures in the internal auditory canal after removal of an acoustic neuroma. AJNR Am J Neuroradiol 1997; 18:313-23. [PMID: 9111669 PMCID: PMC8338588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE To identify patterns of enhancement in the internal auditory canal (IAC) on MR studies after removal of an acoustic neuroma, including changes in those patterns with time; to evaluate signal and enhancement of the labyrinth; to differentiate normal postoperative findings from those suggesting residual tumor; and to describe MR hallmarks of surgical approaches. METHODS We reviewed the postoperative MR studies obtained in 36 patients who had had surgery for acoustic neuroma (101 images total). Four patterns of IAC enhancement were evaluated, as was labyrinthine signal intensity before and after contrast administration, changes in findings over time, and anatomic alterations caused by surgery. RESULTS All patients had enhancement of the IAC on the first postoperative study. In 30 patients, IAC enhancement remained the same or decreased over time. Seventeen patients had hyperintense cochlear signal and 15 had cochlear enhancement that decreased with time. Effects of retrosigmoid craniotomy, a translabyrinthine surgical approach, and middle fossa craniotomy were recognizable. CONCLUSION Linear enhancement in the IAC is probably normal after surgery. Nodular and masslike enhancement and any progressive enhancement may require close follow-up to monitor growth of residual tumor. Labyrinthine hyperintensity may reflect blood metabolites. An MR protocol is suggested for following up patients in the years after surgery.
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Affiliation(s)
- J L Weissman
- Department of Radiology, University of Pittsburgh, School of Medicine, Pa, USA
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Hirsch BE, Kamerer DB. Intratympanic gentamicin therapy for Ménière's disease. Am J Otol 1997; 18:44-51. [PMID: 8989951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate the efficacy and toxicity of intratympanic gentamicin therapy for the treatment of Meniere's disease. STUDY DESIGN We compared retrospective case series with historical controls. SETTING A tertiary referral center--the ambulatory clinic at The University of Pittsburgh Medical Center. PATIENTS The study consisted of 28 patients with Meniere's disease who failed conventional medical therapy and were offered gentamicin treatment or surgical intervention. Patients had to be followed for at least 2 years to be eligible for review. INTERVENTION Intratympanic gentamicin solution injections were given by serial titration to the involved ear on a weekly or biweekly schedule. MAIN OUTCOME MEASURES Adhering to the American Academy of Otolaryngology--Head and Neck Surgery 1985 criteria for reporting treatment results in Meniere's disease, the hearing status, control of vertigo, and disability scores using intratympanic gentamicin therapy were reported and compared with historical controls. RESULTS Complete or substantial control of vertigo was achieved in 91% of patients. Hearing loss occurred in approximately one third of patients. Historically, similar hearing loss occurs in patients who were treated successfully, either medically or surgically. Ototoxicity (high frequency hearing loss) was more likely to be seen in patients with pre-treatment 8,000 Hz hearing thresholds better than 65dB. CONCLUSIONS Intratympanic gentamicin therapy given by serial titration injections provides significant control of vertigo without the significant cost and potential morbidity of a more invasive surgical procedure.
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Affiliation(s)
- B E Hirsch
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania, U.S.A
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Weissman JL, Snyderman CH, Hirsch BE. Hydroxyapatite cement to repair skull base defects: radiologic appearance. AJNR Am J Neuroradiol 1996; 17:1569-74. [PMID: 8883658 PMCID: PMC8338722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE To describe the radiologic appearance of hydroxyapatite cement (HAC), which, when mixed with liquid, forms a paste that can be contoured to osseous defects and, over time, becomes "osseointegrated" (native bone grows into the pores of the HAC and forms a strong chemical bond with the substance). METHODS Between March 1992 and June 1993, 24 adults (16 men, eight women) underwent skull base surgery that included reconstruction or closure with HAC. Fourteen patients had HAC placed in the paranasal sinuses or facial bones, and 10 had HAC placed in the mastoid cavity. RESULTS HAC is homogeneously radiopaque on CT scans and plain radiographs. Large amounts (ablating a frontal sinus or mastoid air cells) are readily seen; small amounts are inconspicuous. On MR images, HAC is a signal void. Infected HAC in one patient was surrounded be enhancing soft tissue on MR images, separated from native bone by an irregular radiolucent cleft on CT scans. CONCLUSIONS HAC is a valuable addition to the surgical armamentarium for the repair of skull base defects. More experience will determine the time course for normal osseointegration, as well as the typical appearance of infection.
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Affiliation(s)
- J L Weissman
- Department of Radiology, University of Pittsburgh (Pa) Medical Center 15213, USA
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Pou AM, Hirsch BE, Durrant JD, Gold SR, Kamerer DB. The efficacy of tympanic electrocochleography in the diagnosis of endolymphatic hydrops. Am J Otol 1996; 17:607-11. [PMID: 8841707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Electrocochleography (ECoG), an objective electrophysiologic test, is useful in the clinical diagnosis of endolymphatic hydrops. The purpose of this study was further to define the role of ECoG in the diagnosis of this disease. A retrospective chart review of 100 patients undergoing tympanic ECoG was undertaken comparing symptoms, degree of hearing loss, duration of disease, and diagnosis with ECoG results. The apparent sensitivity and specificity of ECoG in the diagnosis of endolymphatic hydrops were determined to be 57% and 94%, respectively. Three of 30 positive ECoG results were falsely positive. Fluctuating hearing loss and the degree of hearing loss (< 40 dB) and duration of disease (< 48 months) were statistically significant in predicting positive ECoG results. We conclude that a positive ECoG result is helpful in objectively confirming the disease. However, a negative result does not rule out hydrops.
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Affiliation(s)
- A M Pou
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania, USA
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Hirsch BE, Durrant JD, Yetiser S, Kamerer DB, Martin WH. Localizing retrocochlear hearing loss. Am J Otol 1996; 17:537-46. [PMID: 8841698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE The origin of acute/sudden hearing loss is multifactorial. The association of vestibular symptoms does not necessarily isolate the pathologic condition to the inner ear. The audiogram provides a screen for differentiating conductive from sensorineural loss but often fails to provide more localizing information. METHODS Three unusual patients with a variety of retrocochlear presentations of hearing loss are presented. Along with conventional auditory brainstem response (ABR) testing, newer auditory tests, including otoacoustic emissions and three-dimensional ABR analysis, can facilitate site-of-lesion testing. Magnetic resonance imaging (MRI) also provides graphic documentation for sources of retrocochlear hearing loss. RESULTS One patient had gamma-knife treatment of an arteriovenous malformation, incurring a localised lesion to the inferior colliculus contralateral to the side of hearing loss. This effectively eliminated wave V, as confirmed by three-dimensional ABR analysis. A second patient with human immunodeficiency virus developed sudden complete hearing loss with retained otoacoustic emissions, confirming a retrocochlear lesion. A third patient with acute otitis media with sudden hearing loss and vertigo had an abnormal ABR and "mass lesion" on MRI. Hearing subsequently returned to normal, as did a repeated scan. CONCLUSIONS The unique aspects of each case of retrocochlear hearing loss and the applied auditory electrophysiologic tests are reviewed.
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Affiliation(s)
- B E Hirsch
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania, USA
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