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  1 / 199 MEDLINE  
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[PMID]:27976852
[Au] Autor:Adhikari A; Eliason JK; Sun J; Bose R; Flannigan DJ; Mohammed OF
[Ad] Endereço:King Abdullah University of Science and Technology , KAUST Solar Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Kingdom of Saudi Arabia.
[Ti] Título:Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique.
[So] Source:ACS Appl Mater Interfaces;9(1):3-16, 2017 01 11.
[Is] ISSN:1944-8252
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.
[Mh] Termos MeSH primário: Microscopia Eletrônica
Espectroscopia de Perda de Energia de Elétrons
[Mh] Termos MeSH secundário: Análise Espectral
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; COMMENT
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170414
[Lr] Data última revisão:
170414
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161216
[St] Status:MEDLINE
[do] DOI:10.1021/acsami.6b12301


  2 / 199 MEDLINE  
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[PMID]:27919801
[Au] Autor:Allard-Vannier E; Hervé-Aubert K; Kaaki K; Blondy T; Shebanova A; Shaitan KV; Ignatova AA; Saboungi ML; Feofanov AV; Chourpa I
[Ad] Endereço:Université François Rabelais de Tours, EA 6295 Nanomédicaments et Nanosondes, UFR des Sciences Pharmaceutiques, 31 avenue Monge, F-37200 Tours, France.
[Ti] Título:Folic acid-capped PEGylated magnetic nanoparticles enter cancer cells mostly via clathrin-dependent endocytosis.
[So] Source:Biochim Biophys Acta;1861(6):1578-1586, 2017 06.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: This work is focused on mechanisms of uptake in cancer cells of rationally designed, covalently assembled nanoparticles, made of superparamagnetic iron oxide nanoparticles (SPIONs), fluorophores (doxorubicin or Nile Blue), polyethylene glycol (PEG) and folic acid (FA), referred hereinafter as SFP-FA. METHODS: SFP-FA were characterized by DLS, zetametry and fluorescence spectroscopy. The SFP-FA uptake in cancer cells was monitored using fluorescence-based methods like fluorescence-assisted cell sorting, CLSM with single-photon and two-photon excitation. The SFP-FA endocytosis was also analyzed with electron microscopy approaches: TEM, HAADF-STEM and EELS. RESULTS: The SFP-FA have zeta potential below -6mW and stable hydrodynamic diameter close to 100nm in aqueous suspensions of pH range from 5 to 8. They contain ca. 109 PEG-FA, 480 PEG-OCH and 22-27 fluorophore molecules per SPION. The fluorophores protected under the PEG shell allows a reliable detection of intracellular NPs. SFP-FA readily enter into all the cancer cell lines studied and accumulate in lysosomes, mostly via clathrin-dependent endocytosis, whatever the FR status on the cells. CONCLUSIONS: The present study highlights the advantages of rational design of nanosystems as well as the possible involvement of direct molecular interactions of PEG and FA with cellular membranes, not limited to FA-FR recognition, in the mechanisms of their endocytosis. GENERAL SIGNIFICANCE: Composition, magnetic and optical properties of the SFP-FA as well their ability to enter cancer cells are promising for their applications in cancer theranosis. Combination of complementary analytical approaches is relevant to understand the nanoparticles behavior in suspension and in contact with cells.
[Mh] Termos MeSH primário: Antibióticos Antineoplásicos/metabolismo
Neoplasias da Mama/metabolismo
Clatrina/metabolismo
Doxorrubicina/metabolismo
Portadores de Fármacos
Endocitose
Ácido Fólico/metabolismo
Magnetismo/métodos
Nanopartículas de Magnetita
Nanomedicina/métodos
Polietilenoglicóis/química
Neoplasias do Colo do Útero/metabolismo
[Mh] Termos MeSH secundário: Antibióticos Antineoplásicos/química
Antibióticos Antineoplásicos/farmacologia
Neoplasias da Mama/tratamento farmacológico
Cavéolas/metabolismo
Vesículas Revestidas por Clatrina/metabolismo
Doxorrubicina/química
Doxorrubicina/farmacologia
Endossomos/metabolismo
Feminino
Ácido Fólico/química
Células HeLa
Seres Humanos
Lisossomos/metabolismo
Células MCF-7
Nanopartículas de Magnetita/química
Microscopia Confocal
Microscopia Eletrônica de Transmissão e Varredura
Microscopia de Fluorescência por Excitação Multifotônica
Espectroscopia de Perda de Energia de Elétrons
Neoplasias do Colo do Útero/tratamento farmacológico
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Antibiotics, Antineoplastic); 0 (Clathrin); 0 (Drug Carriers); 0 (Magnetite Nanoparticles); 30IQX730WE (Polyethylene Glycols); 80168379AG (Doxorubicin); 935E97BOY8 (Folic Acid)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161207
[St] Status:MEDLINE


  3 / 199 MEDLINE  
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[PMID]:27258899
[Au] Autor:Freitas ET; Stroppa DG; Montoro LA; de Mello JW; Gasparon M; Ciminelli VS
[Ad] Endereço:Universidade Federal de Minas Gerais, Center of Microscopy, Belo Horizonte 31270901, Brazil; The University of Queensland, School of Earth Sciences, St Lucia 4072, Australia; National Institute of Science and Technology on Minerals Resources, Water and Biodiversity, INCT-Acqua, Brazil. Electronic ad
[Ti] Título:Arsenic entrapment by nanocrystals of Al-magnetite: The role of Al in crystal growth and As retention.
[So] Source:Chemosphere;158:91-9, 2016 Sep.
[Is] ISSN:1879-1298
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The nature of As-Al-Fe co-precipitates aged for 120 days are investigated in detail by High Resolution Transmission Electron Microscopy (HRTEM), Scanning TEM (STEM), electron diffraction, Energy Dispersive X-Ray Spectroscopy (EDS), Electron Energy-Loss Spectroscopy (EELS), and Energy Filtered Transmission Electron Microscopy (EFTEM). The Al present in magnetite is shown to favour As incorporation (up to 1.10 wt%) relative to Al-free magnetite and Al-goethite, but As uptake by Al-magnetite decreases with increasing Al substitution (3.53-11.37 mol% Al). Arsenic-bearing magnetite and goethite mesocrystals (MCs) are formed by oriented aggregation (OA) of primary nanoparticles (NPs). Well-crystalline magnetite likely formed by Otswald ripening was predominant in the Al-free system. The As content in Al-goethite MCs (having approximately 13% substituted Al) was close to the EDS detection limit (0.1 wt% As), but was below detection in Al-goethites with 23.00-32.19 mol% Al. Our results show for the first time the capacity of Al-magnetite to incorporate more As than Al-free magnetite, and the role of Al in favouring OA-based crystal growth under the experimental conditions, and therefore As retention in the formed MCs. The proposed mechanism of As incorporation involves adsorption of As onto the newly formed NPs. Arsenic is then trapped in the MCs as they grow by self-assembly OA upon attachment of the NPs. We conclude that Al may diffuse to the crystal faces with high surface energy to reduce the total energy of the system during the attachment events, thus favouring the oriented aggregation.
[Mh] Termos MeSH primário: Alumínio/química
Arsênico/isolamento & purificação
Nanopartículas de Magnetita/química
Nanopartículas/química
Nanotecnologia/métodos
[Mh] Termos MeSH secundário: Adsorção
Arsênico/química
Cristalização
Recuperação e Remediação Ambiental
Óxido Ferroso-Férrico/química
Compostos de Ferro/química
Nanopartículas Metálicas/química
Microscopia Eletrônica de Transmissão e Varredura
Microscopia Eletrônica de Transmissão
Minerais/química
Espectroscopia de Perda de Energia de Elétrons
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Iron Compounds); 0 (Magnetite Nanoparticles); 0 (Minerals); 1310-14-1 (goethite); CPD4NFA903 (Aluminum); N712M78A8G (Arsenic); XM0M87F357 (Ferrosoferric Oxide)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170817
[Lr] Data última revisão:
170817
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160604
[St] Status:MEDLINE


  4 / 199 MEDLINE  
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[PMID]:26961578
[Au] Autor:Rez P; Aoki T; March K; Gur D; Krivanek OL; Dellby N; Lovejoy TC; Wolf SG; Cohen H
[Ad] Endereço:Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
[Ti] Título:Damage-free vibrational spectroscopy of biological materials in the electron microscope.
[So] Source:Nat Commun;7:10945, 2016 Mar 10.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an 'aloof' electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies <1 eV can be 'safely' investigated. To demonstrate the potential of aloof spectroscopy, we record electron energy loss spectra from biogenic guanine crystals in their native state, resolving their characteristic C-H, N-H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ∼10 nm, simultaneously combined with imaging in the electron microscope.
[Mh] Termos MeSH primário: Guanina/química
Microscopia Eletrônica de Transmissão/instrumentação
Espectroscopia de Perda de Energia de Elétrons/métodos
Espectroscopia de Infravermelho com Transformada de Fourier/métodos
Vibração
[Mh] Termos MeSH secundário: Animais
Carpas
Microscopia Eletrônica/instrumentação
Análise Espectral/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
5Z93L87A1R (Guanine)
[Em] Mês de entrada:1607
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160311
[St] Status:MEDLINE
[do] DOI:10.1038/ncomms10945


  5 / 199 MEDLINE  
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[PMID]:26914999
[Au] Autor:Attarian Shandiz M; Guinel MJ; Ahmadi M; Gauvin R
[Ad] Endereço:1Department of Materials Engineering,McGill University,Montreal,H3A 0C5,Canada.
[Ti] Título:Monte Carlo Simulations of Electron Energy-Loss Spectra with the Addition of Fine Structure from Density Functional Theory Calculations.
[So] Source:Microsc Microanal;22(1):219-29, 2016 Feb.
[Is] ISSN:1435-8115
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:A new approach is presented to introduce the fine structure of core-loss excitations into the electron energy-loss spectra of ionization edges by Monte Carlo simulations based on an optical oscillator model. The optical oscillator strength is refined using the calculated electron energy-loss near-edge structure by density functional theory calculations. This approach can predict the effects of multiple scattering and thickness on the fine structure of ionization edges. In addition, effects of the fitting range for background removal and the integration range under the ionization edge on signal-to-noise ratio are investigated.
[Mh] Termos MeSH primário: Processamento Automatizado de Dados
Espectroscopia de Perda de Energia de Elétrons/métodos
[Mh] Termos MeSH secundário: Método de Monte Carlo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1611
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160226
[St] Status:MEDLINE
[do] DOI:10.1017/S1431927615015603


  6 / 199 MEDLINE  
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[PMID]:26792384
[Au] Autor:Römer I; Wang ZW; Merrifield RC; Palmer RE; Lead J
[Ad] Endereço:School of Geography Earth and Environmental Sciences, University of Birmingham , Edgbaston, Birmingham B15 2TT, United Kingdom.
[Ti] Título:High Resolution STEM-EELS Study of Silver Nanoparticles Exposed to Light and Humic Substances.
[So] Source:Environ Sci Technol;50(5):2183-90, 2016 Mar 01.
[Is] ISSN:1520-5851
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Nanoparticles (NPs) are defined as particles with at least one dimension between 1 and 100 nm or with properties that differ from their bulk material, which possess unique properties. The extensive use of NPs means that discharge to the environment is likely increasing, but fate, behavior, and effects under environmentally relevant conditions are insufficiently studied. This paper focuses on the transformations of silver nanoparticles (AgNPs) under simulated but realistic environmental conditions. High resolution aberration-corrected scanning transmission electron microscopy (HAADF STEM) coupled with electron energy loss spectroscopy (EELS) and UV-vis were used within a multimethod approach to study morphology, surface chemistry transformations, and corona formation. Although loss, most likely by dissolution, was observed, there was no direct evidence of oxidation from the STEM-EELS. However, in the presence of fulvic acid (FA), a 1.3 nm oxygen-containing corona was observed around the AgNPs in water; modeled data based on the HAADF signal at near atomic resolution suggest this was an FA corona was formed and was not silver oxide, which was coherent (i.e., fully coated in FA), where observed. The corona further colloidally stabilized the NPs for periods of weeks to months, dependent on the solution conditions.
[Mh] Termos MeSH primário: Substâncias Húmicas
Nanopartículas Metálicas/química
Microscopia Eletrônica de Transmissão e Varredura/métodos
Prata/química
Espectroscopia de Perda de Energia de Elétrons/métodos
[Mh] Termos MeSH secundário: Benzopiranos/química
Água Doce/química
Luz
Oxirredução
Óxidos/química
Compostos de Prata/química
Espectrofotometria Ultravioleta
Poluentes Químicos da Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Benzopyrans); 0 (Humic Substances); 0 (Oxides); 0 (Silver Compounds); 0 (Water Pollutants, Chemical); 3M4G523W1G (Silver); 897WUN6G6T (disilver oxide); XII14C5FXV (fulvic acid)
[Em] Mês de entrada:1610
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160122
[St] Status:MEDLINE
[do] DOI:10.1021/acs.est.5b04088


  7 / 199 MEDLINE  
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[PMID]:26763451
[Au] Autor:Coroaba A; Pinteala T; Chiriac A; Chiriac AE; Simionescu BC; Pinteala M
[Ad] Endereço:Centre of Advanced Research in Bionanoconjugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry of Romanian Academy, Iasi, Romania; The East European Network of Excellence for Research and Development in Chronic Diseases CHRONEX-RD, "Grigore T. Popa" University of Medicine and P
[Ti] Título:Degradation Mechanism Induced by Psoriasis in Human Fingernails: A Different Approach.
[So] Source:J Invest Dermatol;136(1):311-3, 2016 Jan.
[Is] ISSN:1523-1747
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Doenças da Unha/patologia
Unhas/ultraestrutura
Psoríase/patologia
[Mh] Termos MeSH secundário: Estudos de Casos e Controles
Feminino
Seres Humanos
Técnicas In Vitro
Masculino
Microscopia Eletrônica
Doenças da Unha/diagnóstico
Psoríase/diagnóstico
Valores de Referência
Espectroscopia de Perda de Energia de Elétrons
Espectroscopia de Infravermelho com Transformada de Fourier
[Pt] Tipo de publicação:COMPARATIVE STUDY; LETTER; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1605
[Cu] Atualização por classe:160114
[Lr] Data última revisão:
160114
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160115
[St] Status:MEDLINE


  8 / 199 MEDLINE  
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[PMID]:26708933
[Au] Autor:Govindarajan M; Rajeswary M; Veerakumar K; Muthukumaran U; Hoti SL; Benelli G
[Ad] Endereço:Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India. Electronic address: drgovindzoo@yahoo.com.
[Ti] Título:Green synthesis and characterization of silver nanoparticles fabricated using Anisomeles indica: Mosquitocidal potential against malaria, dengue and Japanese encephalitis vectors.
[So] Source:Exp Parasitol;161:40-7, 2016 Feb.
[Is] ISSN:1090-2449
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Mosquitoes (Diptera: Culicidae) represent a key threat for millions of people worldwide, since they act as vectors for devastating parasites and pathogens. In this scenario, eco-friendly control tools against mosquito vectors are a priority. Green synthesis of silver nanoparticles (AgNP) using a cheap, aqueous leaf extract of Anisomeles indica by reduction of Ag(+) ions from silver nitrate solution has been investigated. Bio-reduced AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of A. indica leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the A. indica leaf extract and AgNP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized AgNP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 31.56, 35.21 and 38.08 µg/mL, respectively. Overall, this study firstly shed light on the mosquitocidal potential of A. indica, a potential bioresource for rapid, cheap and effective AgNP synthesis.
[Mh] Termos MeSH primário: Culicidae
Insetos Vetores
Inseticidas
Lamiaceae/química
Nanopartículas Metálicas
Extratos Vegetais
[Mh] Termos MeSH secundário: Animais
Dengue/prevenção & controle
Dengue/transmissão
Encefalite Japonesa/prevenção & controle
Encefalite Japonesa/transmissão
Malária/prevenção & controle
Malária/transmissão
Microscopia Eletrônica de Varredura
Microscopia Eletrônica de Transmissão
Folhas de Planta/química
Prata
Organismos Livres de Patógenos Específicos
Espectrofotometria Ultravioleta
Espectroscopia de Perda de Energia de Elétrons
Espectroscopia de Infravermelho com Transformada de Fourier
Difração de Raios X
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Insecticides); 0 (Plant Extracts); 3M4G523W1G (Silver)
[Em] Mês de entrada:1605
[Cu] Atualização por classe:160118
[Lr] Data última revisão:
160118
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151229
[St] Status:MEDLINE


  9 / 199 MEDLINE  
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[PMID]:26554927
[Au] Autor:Dogra Y; Arkill KP; Elgy C; Stolpe B; Lead J; Valsami-Jones E; Tyler CR; Galloway TS
[Ad] Endereço:a Department of Biosciences , College of Life and Environmental Sciences, The Geoffrey Pope Building, University of Exeter , Exeter , UK .
[Ti] Título:Cerium oxide nanoparticles induce oxidative stress in the sediment-dwelling amphipod Corophium volutator.
[So] Source:Nanotoxicology;10(4):480-7, 2016.
[Is] ISSN:1743-5404
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Cerium oxide nanoparticles (CeO2 NPs) exhibit fast valence exchange between Ce(IV) and Ce(III) associated with oxygen storage and both pro and antioxidant activities have been reported in laboratory models. The reactivity of CeO2 NPs once they are released into the aquatic environment is virtually unknown, but this is important to determine for assessing their environmental risk. Here, we show that amphipods (Corophium volutator) grown in marine sediments containing CeO2 NPs showed a significant increase in oxidative damage compared to those grown in sediments without NPs and those containing large-sized (bulk) CeO2 particles. There was no exposure effect on survival, but significant increases in single-strand DNA breaks, lipid peroxidation and superoxide dismutase activity were observed after a 10-day exposure to 12.5 mg L(-1) CeO2. Characterisation of the CeO2 NPs dispersed in deionised or saline exposure waters revealed that more radicals were produced by CeO2 NPs compared with bulk CeO2. Electron energy loss spectroscopy (EELS) analysis revealed that both CeO2 NPs were predominantly Ce(III) in saline waters compared to deionised waters where they were predominantly Ce(IV). In both types of medium, the bulk CeO2 consisted mainly of Ce(IV). These results support a model whereby redox cycling of CeO2 NPs between Ce(III) and Ce(IV) is enhanced in saline waters, leading to sublethal oxidative damage to tissues in our test organism.
[Mh] Termos MeSH primário: Anfípodes/efeitos dos fármacos
Anfípodes/metabolismo
Cério/toxicidade
Sedimentos Geológicos
Nanopartículas/toxicidade
Estresse Oxidativo/efeitos dos fármacos
[Mh] Termos MeSH secundário: Animais
Disponibilidade Biológica
Cério/química
Cério/farmacocinética
Quebras de DNA/efeitos dos fármacos
Peroxidação de Lipídeos/efeitos dos fármacos
Nanopartículas/química
Nanopartículas/metabolismo
Espectroscopia de Perda de Energia de Elétrons
Superóxido Dismutase/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
30K4522N6T (Cerium); 619G5K328Y (ceric oxide); EC 1.15.1.1 (Superoxide Dismutase)
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170213
[Lr] Data última revisão:
170213
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151112
[St] Status:MEDLINE
[do] DOI:10.3109/17435390.2015.1088587


  10 / 199 MEDLINE  
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[PMID]:26606369
[Au] Autor:Houplin J; Dablemont C; Sala L; Lafosse A; Amiaud L
[Ad] Endereço:Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay , F-91405 Orsay, France.
[Ti] Título:Electron Processing at 50 eV of Terphenylthiol Self-Assembled Monolayers: Contributions of Primary and Secondary Electrons.
[So] Source:Langmuir;31(50):13528-34, 2015 Dec 22.
[Is] ISSN:1520-5827
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Aromatic self-assembled monolayers (SAMs) can serve as platforms for development of supramolecular assemblies driven by surface templates. For many applications, electron processing is used to locally reinforce the layer. To achieve better control of the irradiation step, chemical transformations induced by electron impact at 50 eV of terphenylthiol SAMs are studied, with these SAMs serving as model aromatic SAMs. High-resolution electron energy loss spectroscopy (HREELS) and electron-stimulated desorption (ESD) of neutral fragment measurements are combined to investigate electron-induced chemical transformation of the layer. The decrease of the CH stretching HREELS signature is mainly attributed to dehydrogenation, without a noticeable hybridization change of the hydrogenated carbon centers. Its evolution as a function of the irradiation dose gives an estimate of the effective hydrogen content loss cross-section, σ = 2.7-4.7 × 10(-17) cm(2). Electron impact ionization is the major primary mechanism involved, with the impact electronic excitation contributing only marginally. Therefore, special attention is given to the contribution of the low-energy secondary electrons to the induced chemistry. The effective cross-section related to dissociative secondary electron attachment at 6 eV is estimated to be 1 order of magnitude smaller. The 1 eV electrons do not induce significant chemical modification for a 2.5 mC cm(-2) dose, excluding their contribution.
[Mh] Termos MeSH primário: Elétrons
Compostos de Sulfidrila/química
[Mh] Termos MeSH secundário: Hidrogênio/química
Espectroscopia de Perda de Energia de Elétrons
Compostos de Sulfidrila/síntese química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Sulfhydryl Compounds); 7YNJ3PO35Z (Hydrogen)
[Em] Mês de entrada:1609
[Cu] Atualização por classe:151222
[Lr] Data última revisão:
151222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151126
[St] Status:MEDLINE
[do] DOI:10.1021/acs.langmuir.5b02109



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