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Loss of biological control of enamel mineralization in amelogenin-phosphorylation-deficient mice. J Struct Biol 2022; 214:107844. [DOI: 10.1016/j.jsb.2022.107844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/18/2022] [Accepted: 02/22/2022] [Indexed: 11/23/2022]
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2
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Black Drum Fish Teeth: Built for Crushing Mollusk Shells. Acta Biomater 2022; 137:147-161. [PMID: 34673226 DOI: 10.1016/j.actbio.2021.10.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/11/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022]
Abstract
With an exclusive diet of hard-shelled mollusks, the black drum fish (Pogonias cromis) exhibits one of the highest bite forces among extant animals. Here we present a systematic microstructural, chemical, crystallographic, and mechanical analysis of the black drum teeth to understand the structural basis for achieving the molluscivorous requirements. At the material level, the outermost enameloid shows higher modulus (Er = 126.9 ± 16.3 GPa, H = 5.0 ± 1.4 GPa) than other reported fish teeth, which is attributed to the stiffening effect of Zn and F doping in apatite crystals and the preferential co-alignment of crystallographic c-axes and enameloid rods along the biting direction. The high fracture toughness (Kc = 1.12 MPa⋅m1/2) of the outer enameloid also promotes local yielding instead of fracture during crushing contact with mollusk shells. At the individual-tooth scale, the molar-like teeth, high density of dentin tubules, enlarged pulp chamber, and specialized dentin-bone connection, all contribute to the functional requirements, including confinement of contact compressive stress in the stiff enameloid, enhanced energy absorption in the compliant dentin, and controlled failure of tooth-bone composite under excessive loads. These results show that the multi-scale structures of black drum teeth are adapted to feed on hard-shelled mollusks. STATEMENT OF SIGNIFICANCE: The black drum fish feeds on hard-shelled mollusks, which requires strong, tough, and wear-resistant teeth. This study presents a comprehensive multiscale material and mechanical analysis of the black drum teeth in achieving such remarkable biological function. At microscale, the fluoride- and zinc-doped apatite crystallites in the outer enameloid region are aligned perpendicular to the chewing surface, representing one of the stiffest biomineralized materials found in nature. In the inner enameloid region, the apatite crystals are arranged into intertwisted rods with crystallographic misorientation for increased crack resistance and toughness. At the macroscale, the molariform geometry, the two-layer design based on the outer enameloid and inner dentin, enlarged pulp chamber and the underlying strong bony toothplate work synergistically to contribute to the teeth's crushing resistance.
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3
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Awad K, Boyes NG, Iqbal R, Ahmed M, Mohamed A, Aswath P, Tomczak CR, Varanasi V. Hepatocyte growth factor administration increases bone soluble phosphate and alters bone chemical structure in diabetic hypertensive rats. JOURNAL OF MATERIALS RESEARCH 2021; 36:3936-3951. [PMID: 34992330 PMCID: PMC8725793 DOI: 10.1557/s43578-021-00300-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 07/06/2021] [Indexed: 06/14/2023]
Abstract
Hepatocyte growth factor (HGF) is a novel potential therapy for improving bone health in patients with type II diabetes and hypertension, but its effect on the bone molecular structure is not revealed yet. Here, X-ray absorption near edge structure (XANES) spectroscopy was used to explore the effects elicited by HGF on the bone chemical structure. This study assessed local calcium (Ca) and phosphorus (P) coordination of diabetic hypertensive rat bones, each with and without HGF treatment. Results revealed that HGF has significant effects on Ca and P coordination chemistry as confirmed by presence of more soluble phosphates in the HGT-treated groups. Data indicated that treated bones have a poorly developed phosphate structure as evidenced by drastic drop in post-edge shoulder in P L2,3-edge compared to diabetic hypertensive and diabetic control bone. Presence of soluble Ca and P, products of bone resorption, with HGF treatment suggests unbalanced bone resorption and formation.
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Affiliation(s)
- Kamal Awad
- Department of Materials Science and Engineering, College of Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
- Bone-Muscle Research Center, College of Nursing & Health Innovation, University of Texas At Arlington, 655 W. Mitchell St., Box 19410, Arlington, TX 76019, USA
- Department of Ceramics and Building Materials, National Research Center, Dokki, Cairo 12622, Egypt
| | - Natasha G. Boyes
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ramlah Iqbal
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada
- Departments of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Mohamed Ahmed
- Departments of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Adel Mohamed
- Departments of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Pranesh Aswath
- Department of Materials Science and Engineering, College of Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Corey R. Tomczak
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Venu Varanasi
- Department of Materials Science and Engineering, College of Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
- Bone-Muscle Research Center, College of Nursing & Health Innovation, University of Texas At Arlington, 655 W. Mitchell St., Box 19410, Arlington, TX 76019, USA
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4
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Stifler CA, Jakes JE, North JD, Green DR, Weaver JC, Gilbert PUPA. Crystal misorientation correlates with hardness in tooth enamels. Acta Biomater 2021; 120:124-134. [PMID: 32711081 DOI: 10.1016/j.actbio.2020.07.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 01/31/2023]
Abstract
The multi-scale hierarchical structure of tooth enamel enables it to withstand a lifetime of damage without catastrophic failure. While many previous studies have investigated structure-function relationships in enamel, the effects of crystal misorientation on mechanical performance have not been assessed. To address this issue, in the present study, we review previously published polarization-dependent imaging contrast (PIC) maps of mouse and human enamel, and parrotfish enameloid, in which crystal orientations were measured and displayed in every 60-nm-pixel. By combining those previous results with the PIC maps of sheep enamel presented here we discovered that, in all enamel(oid)s, adjacent crystals are slightly misoriented, with misorientation angles in the 0°-30° range, and mean 2°-8°. Within this limited range, misorientation is positively correlated with literature hardness values, demonstrating an important structure-property relation, not previously identified. At greater misorientation angles 8°30°, this correlation is expected to reverse direction, but data from different non-enamel systems, with more diverse crystal misorientations, are required to determine if and where this occurs. STATEMENT OF SIGNIFICANCE: We identify a structure-function relationship in tooth enamels from different species: crystal misorientation correlates with hardness, contributing to the remarkable mechanical properties of enamel in diverse animals.
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Affiliation(s)
- Cayla A Stifler
- Department of Physics, University of Wisconsin, Madison, WI 53706, United States
| | - Joseph E Jakes
- Forest Biopolymers Science and Engineering, USDA Forest Service, Forest Products Laboratory, Madison, WI 53726, United States
| | - Jamie D North
- Department of Chemistry, Carleton College, Northfield, MN 55057, United States
| | - Daniel R Green
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States
| | - James C Weaver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, United States
| | - Pupa U P A Gilbert
- Department of Physics, University of Wisconsin, Madison, WI 53706, United States; Departments of Chemistry, Geoscience, Materials Science, University of Wisconsin, Madison, WI 53706, United States.
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5
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Vector Potential Photoelectron Microscopy Instrument Design. Ultramicroscopy 2020; 215:113022. [PMID: 32534366 DOI: 10.1016/j.ultramic.2020.113022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/03/2020] [Accepted: 05/07/2020] [Indexed: 11/22/2022]
Abstract
This report covers the main aspects of designing a vector potential photoelectron microscope (VPPEM). While the VPPEM is straightforward in concept, there are several areas where the optimum configuration of the optics is not immediately obvious, and compromises must be made to make a practical instrument. This report summarizes our instrumental setups, and some basic design issues.
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Abstract
Enamel is the hardest and most resilient tissue in the human body. Enamel includes morphologically aligned, parallel, ∼50 nm wide, microns-long nanocrystals, bundled either into 5-μm-wide rods or their space-filling interrod. The orientation of enamel crystals, however, is poorly understood. Here we show that the crystalline c-axes are homogenously oriented in interrod crystals across most of the enamel layer thickness. Within each rod crystals are not co-oriented with one another or with the long axis of the rod, as previously assumed: the c-axes of adjacent nanocrystals are most frequently mis-oriented by 1°-30°, and this orientation within each rod gradually changes, with an overall angle spread that is never zero, but varies between 30°-90° within one rod. Molecular dynamics simulations demonstrate that the observed mis-orientations of adjacent crystals induce crack deflection. This toughening mechanism contributes to the unique resilience of enamel, which lasts a lifetime under extreme physical and chemical challenges.
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7
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Skallberg A, Bunnfors K, Brommesson C, Uvdal K. Neutrophils Activated by Nanoparticles and Formation of Neutrophil Extracellular Traps: Work Function Mapping and Element Specific Imaging. Anal Chem 2019; 91:13514-13520. [DOI: 10.1021/acs.analchem.9b02579] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- A. Skallberg
- Department of Physics, Chemistry and Biology (IFM), Division of Molecular Surface Physics and Nano Science, Linköping University, Linköping SE-581 83, Sweden
| | - K. Bunnfors
- Department of Physics, Chemistry and Biology (IFM), Division of Molecular Surface Physics and Nano Science, Linköping University, Linköping SE-581 83, Sweden
| | - C. Brommesson
- Department of Physics, Chemistry and Biology (IFM), Division of Molecular Surface Physics and Nano Science, Linköping University, Linköping SE-581 83, Sweden
| | - K. Uvdal
- Department of Physics, Chemistry and Biology (IFM), Division of Molecular Surface Physics and Nano Science, Linköping University, Linköping SE-581 83, Sweden
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8
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Imaging XPS and photoemission electron microscopy; surface chemical mapping and blood cell visualization. Biointerphases 2017; 12:02C408. [DOI: 10.1116/1.4982644] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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9
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Palina N, Wang L, Dash S, Yu X, Breese MBH, Wang J, Rusydi A. Investigation of the metal-insulator transition in NdNiO 3 films by site-selective X-ray absorption spectroscopy. NANOSCALE 2017; 9:6094-6102. [PMID: 28447095 DOI: 10.1039/c7nr00742f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, multifunctional oxide NdNiO3 (NNO) thin films grown on a SrTiO3 (STO) substrate using pulsed-laser deposition are studied. Temperature dependent resistivity measurements revealed that NNO/STO samples exhibit a sharp thickness dependent metal-insulator transition (MIT) over a range of 150-200 K. It is known that the electronic properties of correlated oxides are extremely complex and sensitive to changes in orbital occupancy. To evaluate the changes in the electronic and/or crystallographic structure responsible for the MIT, a site-selective (O, Ni and Nd) X-ray absorption near edge structure (XANES) analysis is performed above and below the transition temperature. Analysis of XANES spectra suggests that: (i) in NNO films nominally trivalent Ni ions exhibit multiple valency (bond disproportionation), (ii) intermetallic hybridization plays an important role, (iii) the presence of strong O 2p-O 2p hole correlation at low temperature results in the opening of the p-p gap and (iv) the valency of Nd ions matches well with that of Nd3+. For NNO films exhibiting a sharp MIT, Ni 3d electron localization and concurrent existence of Ni 3d8 and Ni 3d8L[combining low line]2 states are responsible for the observed transition. At temperatures below the MIT the O 2p-O 2p hole correlation is strong enough to split the O 2p band stabilizing insulating phase. Temperature and thickness dependent differences observed in the site-selective XANES data are discussed in terms of possible mechanisms for the MIT (negative charge-transfer type).
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Affiliation(s)
- Natalia Palina
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore. and NUSNNI-Nanocore, National University of Singapore, Singapore 117411, Singapore
| | - Le Wang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Sibashisa Dash
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore. and School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore and Department of Applied Physics, Waseda University, Shinjuku, Tokyo 169-8555, Japan
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
| | - Mark B H Breese
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore. and Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Junling Wang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Andrivo Rusydi
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore. and NUSNNI-Nanocore, National University of Singapore, Singapore 117411, Singapore and Department of Physics, National University of Singapore, Singapore 117542, Singapore
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10
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Palina N, Annadi A, Asmara TC, Diao C, Yu X, Breese MBH, Venkatesan T, Ariando A, Rusydi A. Electronic defect states at the LaAlO3/SrTiO3 heterointerface revealed by O K-edge X-ray absorption spectroscopy. Phys Chem Chem Phys 2016; 18:13844-51. [DOI: 10.1039/c6cp00028b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interfaces of two dissimilar complex oxides exhibit exotic physical properties that are absent in their parent compounds.
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Affiliation(s)
- Natalia Palina
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
- NUSNNI-Nanocore
| | - Anil Annadi
- NUSNNI-Nanocore
- National University of Singapore
- Singapore 117411
- Singapore
- Department of Physics and Astronomy
| | - Teguh Citra Asmara
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
- NUSNNI-Nanocore
| | - Caozheng Diao
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
| | - Mark B. H. Breese
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
- Department of Physics
| | - T. Venkatesan
- NUSNNI-Nanocore
- National University of Singapore
- Singapore 117411
- Singapore
- Department of Physics
| | - Ariando Ariando
- NUSNNI-Nanocore
- National University of Singapore
- Singapore 117411
- Singapore
- Department of Physics
| | - Andrivo Rusydi
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
- NUSNNI-Nanocore
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11
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DeVol RT, Sun CY, Marcus MA, Coppersmith SN, Myneni SCB, Gilbert PU. Nanoscale Transforming Mineral Phases in Fresh Nacre. J Am Chem Soc 2015; 137:13325-33. [DOI: 10.1021/jacs.5b07931] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ross T. DeVol
- Department
of Physics, University of Wisconsin−Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Chang-Yu Sun
- Department
of Physics, University of Wisconsin−Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Matthew A. Marcus
- Advanced
Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - Susan N. Coppersmith
- Department
of Physics, University of Wisconsin−Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Satish C. B. Myneni
- Department
of Geosciences, Princeton University, Princeton, New Jersey 08544, United States
| | - Pupa U.P.A. Gilbert
- Department
of Physics, University of Wisconsin−Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
- Department
of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Radcliffe
Institute for Advanced Study, Harvard University, 8 Garden Street, Cambridge, Massachusetts 02138, United States
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12
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DeVol RT, Metzler RA, Kabalah-Amitai L, Pokroy B, Politi Y, Gal A, Addadi L, Weiner S, Fernandez-Martinez A, Demichelis R, Gale JD, Ihli J, Meldrum FC, Blonsky AZ, Killian CE, Salling CB, Young AT, Marcus MA, Scholl A, Doran A, Jenkins C, Bechtel HA, Gilbert PUPA. Oxygen spectroscopy and polarization-dependent imaging contrast (PIC)-mapping of calcium carbonate minerals and biominerals. J Phys Chem B 2014; 118:8449-57. [PMID: 24821199 DOI: 10.1021/jp503700g] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
X-ray absorption near-edge structure (XANES) spectroscopy and spectromicroscopy have been extensively used to characterize biominerals. Using either Ca or C spectra, unique information has been obtained regarding amorphous biominerals and nanocrystal orientations. Building on these results, we demonstrate that recording XANES spectra of calcium carbonate at the oxygen K-edge enables polarization-dependent imaging contrast (PIC) mapping with unprecedented contrast, signal-to-noise ratio, and magnification. O and Ca spectra are presented for six calcium carbonate minerals: aragonite, calcite, vaterite, monohydrocalcite, and both hydrated and anhydrous amorphous calcium carbonate. The crystalline minerals reveal excellent agreement of the extent and direction of polarization dependences in simulated and experimental XANES spectra due to X-ray linear dichroism. This effect is particularly strong for aragonite, calcite, and vaterite. In natural biominerals, oxygen PIC-mapping generated high-magnification maps of unprecedented clarity from nacre and prismatic structures and their interface in Mytilus californianus shells. These maps revealed blocky aragonite crystals at the nacre-prismatic boundary and the narrowest calcite needle-prisms. In the tunic spicules of Herdmania momus, O PIC-mapping revealed the size and arrangement of some of the largest vaterite single crystals known. O spectroscopy therefore enables the simultaneous measurement of chemical and orientational information in CaCO3 biominerals and is thus a powerful means for analyzing these and other complex materials. As described here, PIC-mapping and spectroscopy at the O K-edge are methods for gathering valuable data that can be carried out using spectromicroscopy beamlines at most synchrotrons without the expense of additional equipment.
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Affiliation(s)
- Ross T DeVol
- Department of Physics, University of Wisconsin-Madison , 1150 University Avenue, Madison, Wisconsin 53706, United States
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Ohkochi T, Kotsugi M, Yamada K, Kawano K, Horiba K, Kitajima F, Oura M, Shiraki S, Hitosugi T, Oshima M, Ono T, Kinoshita T, Muro T, Watanabe Y. Capability of insulator study by photoemission electron microscopy at SPring-8. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:620-5. [PMID: 23765305 PMCID: PMC4032072 DOI: 10.1107/s0909049513012508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 05/07/2013] [Indexed: 06/02/2023]
Abstract
The observation method of photoemission electron microscopy (PEEM) on insulating samples has been established in an extremely simple way. Surface conductivity is induced locally on an insulating surface by continuous radiation of soft X-rays, and Au films close to the area of interest allow the accumulated charges on the insulated area to be released to ground level. Magnetic domain observations of a NiZn ferrite, local X-ray absorption spectroscopy of sapphire, high-resolution imaging of a poorly conducting Li0.9CoO2 film surface, and Au pattern evaporation on a fine rock particle are demonstrated. Using this technique, all users' experiments on poorly conducting samples have been performed successfully at the PEEM experimental station of SPring-8.
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Affiliation(s)
- Takuo Ohkochi
- Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
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Johnson CJ, Gilbert P, Abrecht M, Baldwin KL, Russell RE, Pedersen JA, Aiken JM, McKenzie D. Low copper and high manganese levels in prion protein plaques. Viruses 2013; 5:654-62. [PMID: 23435237 PMCID: PMC3640519 DOI: 10.3390/v5020654] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 01/25/2013] [Accepted: 02/07/2013] [Indexed: 01/29/2023] Open
Abstract
Accumulation of aggregates rich in an abnormally folded form of the prion protein characterize the neurodegeneration caused by transmissible spongiform encephalopathies (TSEs). The molecular triggers of plaque formation and neurodegeneration remain unknown, but analyses of TSE-infected brain homogenates and preparations enriched for abnormal prion protein suggest that reduced levels of copper and increased levels of manganese are associated with disease. The objectives of this study were to: (1) assess copper and manganese levels in healthy and TSE-infected Syrian hamster brain homogenates; (2) determine if the distribution of these metals can be mapped in TSE-infected brain tissue using X-ray photoelectron emission microscopy (X-PEEM) with synchrotron radiation; and (3) use X-PEEM to assess the relative amounts of copper and manganese in prion plaques in situ. In agreement with studies of other TSEs and species, we found reduced brain levels of copper and increased levels of manganese associated with disease in our hamster model. We also found that the in situ levels of these metals in brainstem were sufficient to image by X-PEEM. Using immunolabeled prion plaques in directly adjacent tissue sections to identify regions to image by X-PEEM, we found a statistically significant relationship of copper-manganese dysregulation in prion plaques: copper was depleted whereas manganese was enriched. These data provide evidence for prion plaques altering local transition metal distribution in the TSE-infected central nervous system.
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Affiliation(s)
- Christopher J. Johnson
- USGS National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711, USA; E-Mails: (C.J.J.); (R.E.R)
| | - P.U.P.A. Gilbert
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706, USA; E-Mails: (P.U.P.A.G.); (M.A.)
| | - Mike Abrecht
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706, USA; E-Mails: (P.U.P.A.G.); (M.A.)
| | - Katherine L. Baldwin
- Program in Cellular & Molecular Biology, University of Wisconsin-Madison, 425-G Henry Mall Madison, WI 53706, USA; E-Mail: (K.L.B.)
| | - Robin E. Russell
- USGS National Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711, USA; E-Mails: (C.J.J.); (R.E.R)
| | - Joel A. Pedersen
- Program in Cellular & Molecular Biology, University of Wisconsin-Madison, 425-G Henry Mall Madison, WI 53706, USA; E-Mail: (K.L.B.)
- Department of Soil Science, University of Wisconsin-Madison, 1525 Observatory Dr., Madison, WI 53706, USA; E-Mail: (J.A.P.)
| | - Judd M. Aiken
- Centre for Prions and Protein Folding Diseases, AFNS, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada; E-Mail: (J.M.A.)
| | - Debbie McKenzie
- Centre for Prions and Protein Folding Diseases, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada; E-Mail: (D.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1 780 492-9377; Fax: +1 780 492-9352
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Olson IC, Gilbert PUPA. Aragonite crystal orientation in mollusk shell nacre may depend on temperature. The angle spread of crystalline aragonite tablets records the water temperature at which nacre was deposited by Pinctada margaritifera. Faraday Discuss 2012. [DOI: 10.1039/c2fd20047c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Mikkelsen A, Schwenke J, Fordell T, Luo G, Klünder K, Hilner E, Anttu N, Zakharov AA, Lundgren E, Mauritsson J, Andersen JN, Xu HQ, L'Huillier A. Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:123703. [PMID: 20059146 DOI: 10.1063/1.3263759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report the first experiments carried out on a new imaging setup, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with the temporal resolution of extreme ultraviolet (XUV) attosecond pulse trains. The very short pulses were provided by high-harmonic generation and used to illuminate lithographic structures and Au nanoparticles, which, in turn, were imaged with a PEEM resolving features below 300 nm. We argue that the spatial resolution is limited by the lack of electron energy filtering in this particular demonstration experiment. Problems with extensive space charge effects, which can occur due to the low probe pulse repetition rate and extremely short duration, are solved by reducing peak intensity while maintaining a sufficient average intensity to allow imaging. Finally, a powerful femtosecond infrared (IR) beam was combined with the XUV beam in a pump-probe setup where delays could be varied from subfemtoseconds to picoseconds. The IR pump beam could induce multiphoton electron emission in resonant features on the surface. The interaction between the electrons emitted by the pump and probe pulses could be observed.
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Affiliation(s)
- A Mikkelsen
- Department of Physics, Lund University, Box 118, 22100 Lund, Sweden
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Crippa PR, Eisner M, Morante S, Stellato F, Vicentin FC, Zecca L. An XAS study of the sulfur environment in human neuromelanin and its synthetic analogs. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:959-70. [PMID: 19471920 DOI: 10.1007/s00249-009-0462-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/09/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022]
Abstract
Neuromelanin is a complex molecule accumulating in the catecholaminergic neurons that undergo a degenerative process in Parkinson's disease. It has been shown to play either a protective or a toxic role depending on whether it is present in the intraneuronal or extraneuronal milieu. Understanding its structure and synthesis mechanisms is mandatory to clarify the reason for this remarkable dual behavior. In the present study, X-ray absorption spectroscopy is employed to investigate the sulfur binding mode in natural human neuromelanin, synthetic neuromelanins, and in certain structurally known model compounds, namely cysteine and decarboxytrichochrome C. Based on comparative fits of human and synthetic neuromelanin spectra in terms of those of model compounds, the occurrence of both cysteine- and trichochrome-like sulfur coordination modes is recognized, and the relative abundance of these two types of structural arrangement is determined. Data on the amount of cysteine- and trichochrome-like sulfur measured in this way indicate that among the synthetic neuromelanins those produced by enzymatic oxidation are the most similar ones to natural neuromelanin. The interest of the method described here lies in the fact that it allows the identification of different sulfur coordination environments in a physically nondestructive way.
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Struis RPWJ, Ludwig C, Barrelet T, Krähenbühl U, Rennenberg H. Studying sulfur functional groups in Norway spruce year rings using S L-edge total electron yield spectroscopy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2008; 403:196-206. [PMID: 18617221 DOI: 10.1016/j.scitotenv.2008.05.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 05/13/2008] [Accepted: 05/21/2008] [Indexed: 05/26/2023]
Abstract
Profiles of the major sulfur functional groups in mature Norway spruce wood tissue have been established for the first time. The big challenge was the development of a method suitable for sulfur speciation in samples with very low sulfur content (<100 ppm). This became possible by synchrotron X-ray absorption spectroscopy at the sulfur L-edge in total electron yield (TEY) detection mode with thin gold-coated wood slices. Functional groups were identified using sulfur compound spectra as fingerprints. Latewood of single year rings revealed metabolic plausible sulfur forms, particularly inorganic sulfide, organic disulfide, methylthiol, and highly oxidized sulfur. Form-specific profiles with Norway spruces from three different Swiss forest sites revealed high, but hitherto little-noticed, sulfur intensities attributable to natural heartwood formation and a common, but physiologically unexpected maximum around year ring 1986 with trees from the industrialized Swiss Plateau. It is hypothesized whether it may have resulted from the huge reduction in sulfur emissions after 1980 due to Swiss policy. Comparison with total S content profiles from optical emission spectroscopy underlined the more accurate and temporally better resolved TEY data with single wood year rings and it opened novel insights into the wood cell chemistry.
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Affiliation(s)
- Rudolf P W J Struis
- Paul Scherrer Institute, General Energy Research Department, LEM, CH-5232 Villigen PSI, Switzerland.
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Kolmakov A, Lanke U, Karam R, Shin J, Jesse S, Kalinin SV. Application of spectromicroscopy tools to explore local origins of sensor activity in quasi-1D oxide nanostructures. NANOTECHNOLOGY 2006; 17:4014-4018. [PMID: 21727530 DOI: 10.1088/0957-4484/17/16/003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have tested a range of imaging and spectroscopic techniques to address their ability to locally explore the interplay between surface reactivity and transport properties of the metal oxide nanostructure wired as a chemiresistor and chemi-FET. In particular, we used scanning surface potential microscopy (SSPM) to monitor the spatial and temporal particularities of the dc potential distributions in an operating device. We also successfully implemented synchrotron radiation-based photoelectron emission microscopy (PEEM) to explore submicron lateral compositional and electronic (work function) inhomogeneity on the surface of an individual nanowire sensor. These results open new avenues to visualize and spectroscopically address the chemical phenomena on an individual quasi-1D nanostructure both in real time and at nano- and mesoscopic level.
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Affiliation(s)
- A Kolmakov
- Physics Department, SIUC, Carbondale, IL 62901, USA
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Lev U, Heun S, Locatelli A, Zolotoyabko E. Imaging of ferroelectric thin films by X-ray photoemission electron microscopy (XPEEM). Ultramicroscopy 2005; 104:169-75. [PMID: 15878238 DOI: 10.1016/j.ultramic.2005.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 03/08/2005] [Accepted: 03/16/2005] [Indexed: 11/19/2022]
Abstract
We performed X-ray photoemission electron microscopy (XPEEM) measurements at the Nanospectroscopy Beamline of the synchrotron light source ELETTRA, Trieste, Italy, to demonstrate the principal possibility of imaging ferroelectric thin films by low-energy photoelectrons. Due to the insulating properties of ferroelectric films, severe surface charging was the major experimental challenge to overcome. This was achieved by grounding an array of gold inter-digital electrodes (with 5 microm blank intervals between them) deposited on top of the films. The images taken with BaTiO(3) films revealed 50-100 nm-sized holes (material discontinuities) on the surface, an observation confirmed by high-resolution scanning electron microscopy (HRSEM). Finer details, e.g. a granular structure, which has been resolved with HRSEM, could not be observed in the XPEEM images. Our measurements indicate that despite some residual charging, a 50 nm lateral resolution can be achieved in XPEEM measurements with ferroelectric films.
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Affiliation(s)
- U Lev
- Department of Materials Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
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De Stasio G, Frazer BH, Gilbert B, Richter KL, Valley JW. Compensation of charging in X-PEEM: a successful test on mineral inclusions in 4.4 Ga old zircon. Ultramicroscopy 2003; 98:57-62. [PMID: 14609643 DOI: 10.1016/s0304-3991(03)00088-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We present a new differential-thickness coating technique to analyze insulating samples with X-ray PhotoElectron Emission spectroMicroscopy (X-PEEM). X-PEEM is non-destructive, analyzes the chemical composition and crystal structure of minerals and can spatially resolve chemical species with a resolution presently reaching 35 nm. We tested the differential coating by analyzing a 4.4 billion-year-old zircon (ZrSiO(4)) containing silicate inclusions. We observed quartz (SiO(2)) inclusions smaller than 1microm in size that can only be analyzed non-destructively with synchrotron spectromicroscopies. With the removal of charging we greatly extend the range of samples that can be analyzed by X-PEEM.
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Affiliation(s)
- Gelsomina De Stasio
- Department of Physics and Synchrotron Radiation Center, University of Wisconsin-Madison, 3731 Schneider Drive, Stoughton, WI 53589, USA.
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High-Resolution Electron Microscopy, Neutron Diffraction with Isotopic Substitution and X-Ray Absorption Fine Structure for the Characterisation of Active Sites in Oxide Catalysts. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0167-2991(01)80131-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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