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Zamanloo MR, Salmanzadeh R, Esrafili MD, Seyednoruziyan B, Imanzadeh GH, Eskandari H. Rotamerism and tautomerism in hydrazone derivatives of ethylacetoacetate: spectroscopic features, Hammett relationships and computational calculations. J PHYS ORG CHEM 2023. [DOI: 10.1002/poc.4487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- M. R. Zamanloo
- Department of Applied Chemistry, Faculty of Basic Science University of Mohaghegh Ardabili Ardabil Iran
| | - R. Salmanzadeh
- Department of Applied Chemistry, Faculty of Basic Science University of Mohaghegh Ardabili Ardabil Iran
| | - M. D. Esrafili
- Laboratory of Theoretical Chemistry, Department of Chemistry University of Maragheh Maragheh Iran
| | - B. Seyednoruziyan
- Department of Applied Chemistry, Faculty of Basic Science University of Mohaghegh Ardabili Ardabil Iran
| | - G. H. Imanzadeh
- Department of Applied Chemistry, Faculty of Basic Science University of Mohaghegh Ardabili Ardabil Iran
| | - H. Eskandari
- Department of Applied Chemistry, Faculty of Basic Science University of Mohaghegh Ardabili Ardabil Iran
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Mohammad-Beigi H, Zanganeh M, Scavenius C, Eskandari H, Farzadfard A, Shojaosadati SA, Enghild JJ, Otzen DE, Buell AK, Sutherland DS. A Protein Corona Modulates Interactions of α-Synuclein with Nanoparticles and Alters the Rates of the Microscopic Steps of Amyloid Formation. ACS Nano 2022; 16:1102-1118. [PMID: 34982538 DOI: 10.1021/acsnano.1c08825] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nanoparticles (NPs) can modulate protein aggregation and fibril formation in the context of amyloid diseases. Understanding the mechanism of this action remains a critical next step in developing nanomedicines for the treatment or prevention of Parkinson's disease. α-Synuclein (α-Syn) can undergo interactions of different strength with nanoparticles, and these interactions can be prevented by the presence of a protein corona (PC) acquired during the exposure of NPs to serum proteins. Here, we develop a method to attach the PC irreversibly to the NPs, which enables us to study in detail the interaction of α-Syn and polyethylenimine-coated carboxyl-modified polystyrene NPs (PsNPs-PEI) and the role of the dynamics of the interactions. Analysis of the kinetics of fibril formation reveals that the NPs surface promotes the primary nucleation step of amyloid fibril formation without significantly affecting the elongation and fragmentation steps or the final equilibrium. Furthermore, the results show that even though α-Syn can access the surface of NPs that are precoated with a PC, due to the dynamic nature of the PC proteins, the PC nevertheless reduces the acceleratoring effect of the NPs. This effect is likely to be caused by reducing the overall amount of weakly interacting α-Syn molecules on the NP surface and the access of further α-Syn required for fibril elongation. Our experimental approach provides microscopic insight into how serum proteins can modulate the complex interplay between NPs and amyloid proteins.
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Affiliation(s)
- Hossein Mohammad-Beigi
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Masumeh Zanganeh
- Biotechnology Group, Faculty of Chemical Engineering, Tarbiat Modares University, 14115-143 Tehran, Iran
| | - Carsten Scavenius
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Hoda Eskandari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Azad Farzadfard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Seyed Abbas Shojaosadati
- Biotechnology Group, Faculty of Chemical Engineering, Tarbiat Modares University, 14115-143 Tehran, Iran
| | - Jan J Enghild
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Duncan S Sutherland
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, 8000 Aarhus C, Denmark
- The Centre for Cellular Signal Patterns (CellPAT), Aarhus University, 8000 Aarhus C, Denmark
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Eskandari H, Ghanadian M, Noleto-Dias C, Lomax C, Tawfike A, Christiansen G, Sutherland DS, Ward JL, Mohammad-Beigi H, Otzen DE. Inhibitors of α-Synuclein Fibrillation and Oligomer Toxicity in Rosa damascena: The All-Pervading Powers of Flavonoids and Phenolic Glycosides. ACS Chem Neurosci 2020; 11:3161-3173. [PMID: 32886481 DOI: 10.1021/acschemneuro.0c00528] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
There is an intense search for natural compounds that can inhibit the oligomerization and fibrillation of α-synuclein (α-Syn), whose aggregation is key to the development of Parkinson's disease (PD). Rosa damascena is a medicinal herb widely used in Middle Eastern food, ceremonies, and perfumes. The herb is known to contain many different polyphenols. Here we investigated the existence of α-Syn fibrillation inhibitors in R. damascena extract. Different HPLC fractions of the extract were assessed in α-Syn fibrillation and toxicity assays. The most active fractions led to the formation of more α-Syn oligomers but with less toxicity to SH-SY5Y cells, according to MTT and LDH assays. LC-MS analysis identified gallic acid, kaempferol 3-glucoside, kaempferol-3-O-β-rutinoside, and quercetin which were subsequently shown to be strong α-Syn fibrillation inhibitors. Our results highlight the benefits of R. damascena extract to combat PD at the population level.
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Affiliation(s)
- Hoda Eskandari
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK− 8000 Aarhus C, Denmark
| | - Mustafa Ghanadian
- Department of Pharmacognosy, Isfahan Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Clarice Noleto-Dias
- Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, U.K
| | - Charlotte Lomax
- Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, U.K
| | - Ahmed Tawfike
- Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, U.K
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, 8000 Aarhus C, Denmark
| | - Duncan S. Sutherland
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK− 8000 Aarhus C, Denmark
| | - Jane L. Ward
- Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, U.K
| | - Hossein Mohammad-Beigi
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK− 8000 Aarhus C, Denmark
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK− 8000 Aarhus C, Denmark
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Mohammad-Beigi H, Hayashi Y, Zeuthen CM, Eskandari H, Scavenius C, Juul-Madsen K, Vorup-Jensen T, Enghild JJ, Sutherland DS. Mapping and identification of soft corona proteins at nanoparticles and their impact on cellular association. Nat Commun 2020; 11:4535. [PMID: 32913217 PMCID: PMC7484794 DOI: 10.1038/s41467-020-18237-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022] Open
Abstract
The current understanding of the biological identity that nanoparticles may acquire in a given biological milieu is mostly inferred from the hard component of the protein corona (HC). The composition of soft corona (SC) proteins and their biological relevance have remained elusive due to the lack of analytical separation methods. Here, we identify a set of specific corona proteins with weak interactions at silica and polystyrene nanoparticles by using an in situ click-chemistry reaction. We show that these SC proteins are present also in the HC, but are specifically enriched after the capture, suggesting that the main distinction between HC and SC is the differential binding strength of the same proteins. Interestingly, the weakly interacting proteins are revealed as modulators of nanoparticle-cell association mainly through their dynamic nature. We therefore highlight that weak interactions of proteins at nanoparticles should be considered when evaluating nano-bio interfaces.
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Affiliation(s)
- Hossein Mohammad-Beigi
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
- The Centre for Cellular Signal Patterns (CellPAT), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
| | - Yuya Hayashi
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus C, Denmark
| | - Christina Moeslund Zeuthen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
- The Centre for Cellular Signal Patterns (CellPAT), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
| | - Hoda Eskandari
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
- The Centre for Cellular Signal Patterns (CellPAT), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark
| | - Carsten Scavenius
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus C, Denmark
| | - Kristian Juul-Madsen
- Department of Biomedicine, Faculty of Health, Aarhus University, Høegh-Guldbergs Gade 10, 8000 Aarhus C, Denmark
| | - Thomas Vorup-Jensen
- Department of Biomedicine, Faculty of Health, Aarhus University, Høegh-Guldbergs Gade 10, 8000 Aarhus C, Denmark
| | - Jan J Enghild
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus C, Denmark
| | - Duncan S Sutherland
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark.
- The Centre for Cellular Signal Patterns (CellPAT), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus C, Denmark.
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Eskandari H, Ehsanpour AA, Al-Mansour N, Bardania H, Sutherland D, Mohammad-Beigi H. Rosmarinic acid inhibits programmed cell death in Solanum tuberosum L. calli under high salinity. Plant Physiol Biochem 2020; 147:54-65. [PMID: 31841962 DOI: 10.1016/j.plaphy.2019.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/10/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Oxidative stress induced by salinity is a prime cause of cell death when Na+ toxicity becomes unbearable. We explored the effect of rosmarinic acid (RA) on the Solanum tuberosum L. cv. Desiree calli against salt-induced programmed cell death (PCD). We showed that PCD events were triggered in calli under 250 mM NaCl by the loss of plasma membrane integrity as measured by the amount of malondialdehyde (MDA) in the cytoplasm, the degree of DNA degradation resulting from the cleavage of nuclear DNA into oligonucleosomal fragments in apoptotic cells, the presence of TUNEL-positive nuclei (90 ± 0.005%) damage in genomic DNA, and activation of caspase 3-like protease. Callus Formation Medium (CFM) supplemented with RA led to the suppression of salt-induced cell death and a dramatic decrease in the MDA level and frequency of TUNEL-positive nuclei under salinity to 4 ± and 7.3 ± % in the presence of 50 and 350 μM RA, respectively. The application of RA also resulted in an increase in GSH content and maintenance of a high GSH/GSSG ratio. Interestingly, these reductions in PCD were accompanied by inhibiting caspase 3-like protease activities due to RA under salinity. Molecular docking predicted high binding energies of RA for binding to subtilisin-like protease (StSCTc-3), which has caspase-3 like activity in Solanum tuberosum, near the active site. This finding supports the notion of a role for RA in PCD protection in plants, which is consistent with earlier reports in animal cells.
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Affiliation(s)
- Hoda Eskandari
- Department of Biology, University of Isfahan, Isfahan, Iran; Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C, 8000, Denmark
| | | | - Naemah Al-Mansour
- Faculty of Science, Department of Biological Sciences, University of Kuwait, Kuwait.
| | - Hassan Bardania
- Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Duncan Sutherland
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C, 8000, Denmark
| | - Hossein Mohammad-Beigi
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus C, 8000, Denmark
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Mohammad-Beigi H, Aliakbari F, Sahin C, Lomax C, Tawfike A, Schafer NP, Amiri-Nowdijeh A, Eskandari H, Møller IM, Hosseini-Mazinani M, Christiansen G, Ward JL, Morshedi D, Otzen DE. Oleuropein derivatives from olive fruit extracts reduce α-synuclein fibrillation and oligomer toxicity. J Biol Chem 2019; 294:4215-4232. [PMID: 30655291 DOI: 10.1074/jbc.ra118.005723] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [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: 09/06/2018] [Revised: 01/09/2019] [Indexed: 11/06/2022] Open
Abstract
Aggregation of α-synuclein (αSN) is implicated in neuronal degeneration in Parkinson's disease and has prompted searches for natural compounds inhibiting αSN aggregation and reducing its tendency to form toxic oligomers. Oil from the olive tree (Olea europaea L.) represents the main source of fat in the Mediterranean diet and contains variable levels of phenolic compounds, many structurally related to the compound oleuropein. Here, using αSN aggregation, fibrillation, size-exclusion chromatography-multiangle light scattering (SEC-MALS)-based assays, and toxicity assays, we systematically screened the fruit extracts of 15 different olive varieties to identify compounds that can inhibit αSN aggregation and oligomer toxicity and also have antioxidant activity. Polyphenol composition differed markedly among varieties. The variety with the most effective antioxidant and aggregation activities, Koroneiki, combined strong inhibition of αSN fibril nucleation and elongation with strong disaggregation activity on preformed fibrils and prevented the formation of toxic αSN oligomers. Fractionation of the Koroneiki extract identified oleuropein aglycone, hydroxyl oleuropein aglycone, and oleuropein as key compounds responsible for the differences in inhibition across the extracts. These phenolic compounds inhibited αSN amyloidogenesis by directing αSN monomers into small αSN oligomers with lower toxicity, thereby suppressing the subsequent fibril growth phase. Our results highlight the molecular consequences of differences in the level of effective phenolic compounds in different olive varieties, insights that have implications for long-term human health.
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Affiliation(s)
- Hossein Mohammad-Beigi
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark,
| | - Farhang Aliakbari
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.,the Departments of Industrial and Environmental Biotechnology and
| | - Cagla Sahin
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.,the Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Charlotte Lomax
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Ahmed Tawfike
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Nicholas P Schafer
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Alireza Amiri-Nowdijeh
- Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, P. O. Box 1417863171, Tehran, Iran
| | - Hoda Eskandari
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Ian Max Møller
- the Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Mehdi Hosseini-Mazinani
- Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, P. O. Box 1417863171, Tehran, Iran
| | - Gunna Christiansen
- the Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, 8000 Aarhus C, Denmark, and
| | - Jane L Ward
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Dina Morshedi
- the Departments of Industrial and Environmental Biotechnology and
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark, .,the Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
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Mohammad-Beigi H, Kjaer L, Eskandari H, Aliakbari F, Christiansen G, Ruvo G, Ward JL, Otzen DE. A Possible Connection Between Plant Longevity and the Absence of Protein Fibrillation: Basis for Identifying Aggregation Inhibitors in Plants. Front Plant Sci 2019; 10:148. [PMID: 30815009 PMCID: PMC6381023 DOI: 10.3389/fpls.2019.00148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/28/2019] [Indexed: 05/08/2023]
Abstract
The ability of proteins to aggregate to form well-organized β-sheet rich amyloid fibrils is increasingly viewed as a general if regrettable property of the polypeptide chain. Aggregation leads to diseases such as amyloidosis and neurodegeneration in humans and various mammalian species but is also found in a functional variety in both animals and microbes. However, there are to our knowledge no reports of amyloid formation in plants. Plants are also the source of a large number of aggregation-inhibiting compounds. We reasoned that the two phenomena could be connected and that one of (many) preconditions for plant longevity is the ability to suppress unwanted protein aggregation. In support of this, we show that while protein extracts from the sugar maple tree Acer saccharum fibrillate readily on their own, this process is efficiently abolished by addition of small molecule extracts from the same plant. Further analysis of 44 plants showed a correlation between plant longevity and ability to inhibit protein aggregation. Extracts from the best performing plant, the sugar maple, were subjected to chromatographic fractionation, leading to the identification of a large number of compounds, many of which were shown to inhibit aggregation in vitro. One cautious interpretation is that it may have been advantageous for plants to maintain an efficient collection of aggregation-inhibiting metabolites as long as they do not impair metabolite function. From a practical perspective, our results indicate that long-lived plants may be particularly appropriate sources of new anti-aggregation compounds with therapeutic potential.
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Affiliation(s)
| | - Lars Kjaer
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Aarhus, Denmark
| | - Hoda Eskandari
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Aarhus, Denmark
| | - Farhang Aliakbari
- Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, Aarhus, Denmark
| | - Gianluca Ruvo
- Computational and Analytical Sciences Department, Rothamsted Research, Harpenden, United Kingdom
| | - Jane L. Ward
- Computational and Analytical Sciences Department, Rothamsted Research, Harpenden, United Kingdom
| | - Daniel Erik Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
- *Correspondence: Daniel Erik Otzen,
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Havashinejadian E, Danaee I, Eskandari H, Nikmanesh S. Investigation on Trend Removal in Time Domain Analysis of Electrochemical Noise Data Using Polynomial Fitting and Moving Average Removal Methods. J ELECTROCHEM SCI TE 2017. [DOI: 10.33961/jecst.2017.8.2.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Goodarzi A, Danaee I, Eskandari H, Nikmanesh S. Electrochemical Corrosion Behavior of Duplex Stainless SteelAISI 2205 in Ethylene Glycol-Water Mixture in the Presence of50 W/V % LiBr. J ELECTROCHEM SCI TE 2016. [DOI: 10.33961/jecst.2016.7.1.58] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Goodarzi A, Danaee I, Eskandari H, Nikmanesh S. Electrochemical Corrosion Behavior of Duplex Stainless SteelAISI 2205 in Ethylene Glycol-Water Mixture in the Presence of50 W/V % LiBr. J ELECTROCHEM SCI TE 2016. [DOI: 10.5229/jecst.2016.7.1.58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Eskandari H, Salcudean SE, Rohling R. Viscoelastic parameter estimation based on spectral analysis. IEEE Trans Ultrason Ferroelectr Freq Control 2008; 55:1611-1625. [PMID: 18986951 DOI: 10.1109/tuffc.2008.839] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This paper introduces a new technique for the robust estimation of relaxation-time distribution in tissue. The main novelty is in the use of the phase of transfer functions calculated from a time series of strain measurements at multiple locations. Computer simulations with simulated measurement noise demonstrate the feasibility of the approach. An experimental apparatus and software were developed to confirm the simulations. The setup can be used both as a rheometer to characterize the overall mechanical properties of a material or as a vibro-elastography imaging device using an ultrasound system. The algorithms were tested on tissue mimicking phantoms specifically developed to exhibit contrast in elasticity and relaxation time. The phantoms were constructed using a combination of gelatin and a polyvinyl alcohol sponge to produce the desired viscoelastic properties. The tissue parameters were estimated and the elasticity and relaxation time of the materials have been used as complementary features to distinguish different materials. The estimation results are consistent with the rheometry, verifying that the relaxation time can be used as a complementary feature to elasticity to delineate the mechanical properties of the phantom.
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Affiliation(s)
- H Eskandari
- Dept. of Electr. & Comput. Eng., Univ. of British Columbia, Vancouver, BC, Canada
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Bagherian G, Chamjangali MA, Eskandari H. Simultaneous determination of cobalt and palladium in micellar media using H-point standard addition method and partial least square regression. Spectrochim Acta A Mol Biomol Spectrosc 2007; 67:378-84. [PMID: 16959535 DOI: 10.1016/j.saa.2006.07.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 07/11/2006] [Accepted: 07/19/2006] [Indexed: 05/11/2023]
Abstract
A simple, sensitive and selective spectrophotometric method for the simultaneous determination of Co(II) and Pd(II) using partial least square (PLS) calibration and H-point standard addition method is described. The method is based on the complex formation of Co(II) and Pd(II) with 4-(2-pyridylazo) resorcinol (PAR) in acidic media and in the presence of sodium dodecyl sulfate (SDS) as a micellizing agent. Acidic media and the presence of a micellar system improve selectivity and sensitivity, respectively. By applying PLS calibration, Co(II) and Pd(II) can be determined in the range of 0.20-2.0 and 0.40-4.0 microg ml(-1), respectively. The relative errors of prediction for the determination of Co(II) and Pd(II) in the 10 prediction samples were 1.69 and 1.72%, respectively. The results of applying H-point standard addition method show that Co(II) and Pd(II) can be determined simultaneously with concentration ratio of Co(II) to Pd(II) varying between 7:1 and 1:8 in the mixed samples. Both proposed methods (PLS and HPSAM) were applied to the determination of Co(II) and Pd(II) in several alloy solutions with satisfactory results.
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Affiliation(s)
- G Bagherian
- College of Chemistry, Shahrood University of Technology, Shahrood, P.O. Box 316, Iran
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Eskandari H, Ghaziaskar HS, Ensafi AA. SOLID–LIQUID SEPARATION AFTER LIQUID–LIQUID EXTRACTION USING α-BENZILMONOXIME-MOLTEN BENZOPHENONE FOR PRECONCENTRATION AND SELECTIVE SPECTROPHOTOMETRIC DETERMINATION OF PALLADIUM. ANAL LETT 2001. [DOI: 10.1081/al-100107534] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Eskandari H, Ghaziaskar HS, Ensafi AA. A sensitive and simple extractive-spectrophotometric method for the determination of microgram amount of cobalt by using alpha-benzilmonoxime. ANAL SCI 2001; 17:327-31. [PMID: 11990550 DOI: 10.2116/analsci.17.327] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Alpha-benzilmonoxime has been used for the extraction and determination of cobalt at microgram amount. The reagent reacts with cobalt(II) in the pH range of 8.8 - 9.3 to form a yellow-color chelate, which is extracted in chloroform, toluene, and some other non-polar solvents. The chelate is stable in chloroform for about one day. Under the optimum conditions of the a-benzilmonoxime concentration and pH of 9.0, Beer's law was obeyed in the concentration range of 0.08 - 2.2 microg/ml cobalt. The molar absorptivity of the extracted species was 2.55 x 10(4) dm3/mol cm at 380 nm, with a detection limit of 0.01 microg/ml cobalt. Relative standard deviations of 0.4, 0.8 and 2.3% were found for the determination of cobalt concentrations of 2.2, 1.1 and 0.08 microg/ml, respectively. The effect of diverse ions on the determination of 1.00 microg/ml of cobalt has been studied. The method was applied to the determination of cobalt in vitamin B12 and B-complex ampoules, a Co2O3-Co3O4 laboratory chemical mixture and some synthetic alloy samples. The method is sensitive, simple, rapid and accurate.
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Affiliation(s)
- H Eskandari
- College of Chemistry, Isfahan University of Technology, Iran
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Eskandari H, Ablin RJ, Bhatti RA. Immunologic responsiveness & tumour growth of the Dunning R3327 rat prostatic adenocarcinoma following cryosurgery & orchiectomy. Indian J Exp Biol 1982; 20:872-4. [PMID: 7183523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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