Bibliografie tematiche / Electron attachment spectroscopy

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Letteratura scientifica selezionata sul tema "Electron attachment spectroscopy"

Autore: Grafiati

Pubblicato: 25 gennaio 2025

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Articoli di riviste sul tema "Electron attachment spectroscopy"

Moylan, Christopher R., Susan Baer Green e John I. Brauman. "Electron attachment chemistry of SiCl4. Relevance to plasma reactions". International Journal of Mass Spectrometry and Ion Processes 96, n. 3 (aprile 1990): 299–307. http://dx.doi.org/10.1016/0168-1176(90)85130-t.

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Alizadeh, E., F. Ferreira da Silva, F. Zappa, A. Mauracher, M. Probst, S. Denifl, A. Bacher, T. D. Märk, P. Limão-Vieira e P. Scheier. "Dissociative electron attachment to nitromethane". International Journal of Mass Spectrometry 271, n. 1-3 (aprile 2008): 15–21. http://dx.doi.org/10.1016/j.ijms.2007.11.004.

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Miller, Thomas M., Jane M. Van Doren e A. A. Viggiano. "Electron attachment and detachment: C6F6". International Journal of Mass Spectrometry 233, n. 1-3 (aprile 2004): 67–73. http://dx.doi.org/10.1016/j.ijms.2003.11.014.

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Luo, T., e A. Khursheed. "Second-order aberration corrected electron energy loss spectroscopy attachment for scanning electron microscopes". Review of Scientific Instruments 77, n. 4 (aprile 2006): 043103. http://dx.doi.org/10.1063/1.2190208.

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Kopyra, Janina, Constanze König-Lehmann, Iwona Szamrej e Eugen Illenberger. "Unusual features in electron attachment to chlorodifluoroacetic acid (CClF2COOH): Strong dissociative electron attachment near 0eV and associative attachment at 0.75eV". International Journal of Mass Spectrometry 285, n. 3 (agosto 2009): 131–36. http://dx.doi.org/10.1016/j.ijms.2009.05.006.

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Anstöter, Cate S., Thomas E. Gartmann, Laurence H. Stanley, Anastasia V. Bochenkova e Jan R. R. Verlet. "Electronic structure of the para-dinitrobenzene radical anion: a combined 2D photoelectron imaging and computational study". Physical Chemistry Chemical Physics 20, n. 37 (2018): 24019–26. http://dx.doi.org/10.1039/c8cp04877k.

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Heni, Martin, e Eugen Illenberger. "Electron attachment by saturated nitriles, acrylonitrile (C2H3CN), and benzonitrile (C6H5CN)". International Journal of Mass Spectrometry and Ion Processes 73, n. 1-2 (novembre 1986): 127–44. http://dx.doi.org/10.1016/0168-1176(86)80014-3.

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N. L. Asfandiarov, M. V. Muftakhov, A. M. Safronov, R.V. Galeev e S. A. Pshenichnyuk. "Non-covalent structures of negative ions formed during the dissociative capture of electrons by molecules". Technical Physics 67, n. 11 (2022): 1425. http://dx.doi.org/10.21883/tp.2022.11.55171.157-22.

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The method of dissociative electron attachment (DEA) spectroscopy was used to study the attachment of electrons to 1-chloronaphthalene molecules. It has been established that the dominant channel for the decay of molecular ions is the formation of Cl- ions in three resonances at 0.7, 1.5, and 3.0 eV. Ions [M-H]- and [M-Cl]- are observed at energies from 3.5 to 8.5 eV and have two to three orders of magnitude lower formation cross sections. Long-lived molecular ions were not registered. Calculations in the DFT CAM B3LYP/6-311+G(d,p) approximation predict the presence of six stable anionic structures in which the chlorine anion is coordinated to the neutral residue via noncovalent H-Cl^--H bonds. The electron affinity of the most stable of these structures coincides with the experimentally measured value EA_a=0.2771±0.003 eV. These results agree with the previously obtained data on the DEA of molecules of bromine-substituted biphenyls, naphthalenes, and anthracenes and confirm the existence of anionic structures with non-covalent H-Hal-H bonds. Such non-covalent anion structures should be extremely reactive, which makes them promising for the synthesis of self-assembling hydrocarbon nanomembranes. Keywords: Attachment of electrons to molecules, electron affinity, potential surface, DFT calculations.

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Mauracher, A., H. Schöbel, S. Haughey, S. E. Huber e T. A. Field. "Dissociative electron attachment to fluorinated nitrobenzenes". International Journal of Mass Spectrometry 471 (gennaio 2022): 116731. http://dx.doi.org/10.1016/j.ijms.2021.116731.

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Barszczewska, Wiesława, Janina Kopyra, Jolanta Wnorowska e Iwona Szamrej. "Low energy electron attachment by bromoalkanes". International Journal of Mass Spectrometry 233, n. 1-3 (aprile 2004): 199–205. http://dx.doi.org/10.1016/j.ijms.2003.12.018.

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Più fonti

Tesi sul tema "Electron attachment spectroscopy"

Houplin, Justine. "Structuration chimique induite et contrôlée par impact d’électrons lents sur films moléculaires supportés". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112124/document.

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Les mono-couches auto-assemblées (SAMs) sont des systèmes de choix pour le développement de plateformes moléculaires aux propriétés physico-chimiques contrôlées. Il s’agit de monocouches organisées de molécules bi-fonctionnelles. Ces molécules se composent d’une fonction terminale modulable, séparée d’un groupement d’ancrage par un espaceur adapté. Ainsi, les propriétés des SAMs peuvent être ajustées pour le développement de systèmes électroniques moléculaires ou de capteurs (bio)-chimiques. De plus, des structurations chimiques supplémentaires peuvent être induites par irradiation.Les méthodes d’irradiation les plus courantes impliquent des particules de haute énergie. Les dommages induits résultent de plusieurs mécanismes en compétition (ionisations, excitations, dissociations). Dans cette thèse, les électrons lents (0-20 eV) sont utilisés comme particules primaires, et les processus d’interaction électron-SAM sont étudiés afin d’identifier les résonances d’attachement électronique. Aux énergies concernées, des processus dissociatifs sélectifs et efficaces peuvent être mis à profit pour proposer des stratégies d’irradiation menant à des modifications chimiques contrôlées et optimisées.Des SAMs modèles de thiols sur or sont étudiées par une technique de spectroscopie vibrationnelle de forte sensibilité de surface, la spectroscopie de perte d’énergie d’électrons lents (HREELS). Elle permet à la fois de caractériser les SAMs et de sonder les processus d'interaction électron-molécule. Les résultats obtenus concernent les : 1) SAMs aromatiques modèles de terphénylthiol (HS-(C₆H₄)₂-C₆H₅), stabilisables par réticulation sous irradiation. Une caractérisation vibrationnelle poussée de la SAM avant et après irradiation, en portant une attention particulière au comportement des modes d’élongation ν(CH), a permis d’opposer les processus de réactivité induite à 1, 6 et 50 eV.2) SAMs d’acide mercaptoundécanoïque (HS-(CH₂)₁ ₀ -COOH), les fonctions acides terminales permettant par exemple le greffage de peptides. L’interface SAM / environnement (COO-/COOH, eau résiduelle) a été caractérisée grâce à la forte sensibilité des modes d’élongation ν(OH) aux liaisons hydrogène. La démarche mise en place peut être facilement transposée à d’autres systèmes
Self-Assembled Monolayers (SAMs) are good candidates to develop molecular platforms with controlled physico-chemical properties. A SAM is an ordered monolayer of bi-functionnal molecules. These molecules consist of an adjustable terminal function, separated from a headgroup by a chosen spacer chain. Thus, SAMs properties can be adjusted for the development of molecular electronic systems or (bio)-chemical sensors. Furthermore, additional chemical structuration can be induced by irradiation.Most current methods of irradiation involve high energy particles. The induced damages result from several competitive mechanisms (ionisations, excitations, dissociations). In this thesis, low energy electrons (0-20 eV) are used as primary particles, and the interaction processes between electrons and SAMs are studied in order to identify electron attachment resonances. At the associated energies, selective and effective dissociative processes can be induced to propose irradiation strategies leading to controlled and optimized chemical modifications.Model SAMs of thiols on gold are studied by a vibrational spectroscopy technique of strong surface sensibility, high resolution electron energy loss spectroscopy (HREELS). It allows at the same time to characterize SAMs and to probe electron-molecule interaction processes. The result obtained deal with : 1) Aromatic model SAMs of Terphenyl-thiol (HS-(C₆H₄)₂-C₆H₅), which can be stabilized by cross-linking under irradiation. Induced reactive processes at 1, 6 and 50 eV were compared and opposed, thanks to an advanced vibrational characterization of the SAM before and after irradiation, and by paying a particular attention to the stretching mode ν(CH) behaviour.2) Mercaptoundecanoic acid SAMs (HS-(CH₂)₁ ₀ -COOH), whose terminal functions allow for example the peptide anchoring. The interface SAM / environment (COO-/COOH, residual water) was characterized thanks to the strong sensitivity of the stretching modes ν(OH) to hydrogen bonding. The approach that was developped can be easily transposed to other systems

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Sedmidubská, Barbora. "The role of the low-energy electrons in the process of radiosensitization". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF069.

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Dans la chimioradiothérapie concomitante, il y a un effort pour augmenter son efficacité et atténuer la toxicité pour les cellules saines. Cela peut être atteint par le biais du synergisme et de la délivrance ciblée de médicaments (DCM). La DCM est un transport sélectif des médicaments vers des sites d'intérêt, protégeant ainsi les tissus sains de la toxicité des agents chimiothérapeutiques. Le synergisme est l'effet maximal de la chimioradiothérapie résultant des interactions complexes entre les deux modalités de traitement, comme l'interaction d'un agent radiosensibilisant avec des électrons de basse énergie (EBE) générés dans les tissus irradiés. Dans ce contexte, la thèse se concentre sur le processus de radiosensibilisation afin d'étudier le potentiel et les mécanismes radiosensibilisants des molécules sélectionnées basés sur leur interaction avec les EBE ; l'objectif est d'obtenir de nouvelles informations permettant de concevoir des radiosensibilisateurs plus efficaces et moins toxiques. La partie théorique traite des radiosensibilisateurs existants et leurs composés modèles du point de vue de l'interaction avec les EBE. La partie expérimentale combine des expériences d'attachement électronique en phase gazeuse et des calculs ab initio des affinités électroniques des molécules étudiées, des expériences de radiolyse pulsée en solution, ainsi que l'irradiation par microtron avec évaluation par la spectroscopie de résonance magnétique nucléaire. Sur la base de l'étude des interactions avec les EBE (secondaires), le potentiel radiosensibilisant a été confirmé pour l'agent antiviral favipiravir ; une interaction significative a été prouvée pour le radiosensibiliseur chimiothérapeutique RRx-001, ainsi qu'une forte interaction des électrons solvatés avec les fullerénols comme une plate-forme radiosensibilisante destinée à la DCM
In concomitant chemoradiotherapy (CCRT), there is an effort to increase its effectiveness and alleviate toxicity for healthy cells. It may be achieved via synergism and targeted drug delivery (TDD). TDD is the selective drug transport to sites of interest, protecting healthy tissue from chemotherapeutic toxicity. The synergism, the highest chemoradioterapeutic effect, results from complex interactions between both treatment modalities, as the interaction of the radiosensitizing chemo-drug with secondary low-energy electrons (LEEs) arising in irradiated tissue. In light of that work focuses on the radiosensitization process to investigate the radiosensitizing potential and mechanisms of selected molecules based on interaction with LEE; there is an aim to obtain new information to design more effective radiosensitizers with lower toxicity. The theoretical part deals with existing radiosensitizers and their model compounds from the point of view of interaction with LEEs. The experimental part combines electron attachment experiments in the gas phase and ab initio calculations of electron affinities of studied molecules, pulse radiolysis experiments in solution, and microtron irradiation with NMR spectroscopic evaluation. Based on the study of interaction with (secondary) LEEs, the radiosensitizing potential was confirmed for the antiviral agent favipiravir; significant interaction was proven for radiosensitizing chemotherapeutic RRx-001 as well, so as a strong interaction of solvated electrons with fullerenols as a radiosensitizing carrier drug for TGM in CCRT
Konkomitantní chemoradioterapie je jedna z důležitých metod léčby rakoviny. Stále existuje snaha zvýšit její účinnost a udržet toxicitu pro zdravé buňky na snesitelné úrovni. Její největší výhodou je synergický efekt plynoucí z mnoha komplexních interakcí mezi oběma léčebnými přístupy (tzn. chemoterapie a radioterapie). Bylo ukázáno, že jednou z příčin synergismu může být interakce chemosložky (tzv. radiosensitizéru) se sekundárními nízkoenergetickými elektrony vznikajícími v hojném počtu během radiolýzy v ozářené tkáni. V této práci se zaměřuji na proces radiosensitizace s cílem prozkoumat radiosensitizační potenciál molekul a odhalit radiosensitizační mechanismy na bázi jejich interakce s nízkoenergetickými elektrony. Motivací této práce bylo získat nové informace pro návrh nových a více účinných radiosensitizérů s menší toxicitou. Práce sestává z teoretické a experimentální části. Teoretická část je postavena na rešerši již existujících radiosensitizérů a jejich modelových sloučenin z pohledu interakce s nízkoenergetickými elektrony. Experimentální část kombinuje experimenty elektronového záchytu v plynné fázi na dvou experimentálních zařízeních, experimenty pulsní radiolýzy v roztoku, dále ozařování na mikrotronu s NMR spektroskopickým vyhodnocením a ab-initio výpočty elektronových afinit studovaných molekul a jejích fragmentů. V této práci bylo studováno antivirotikum favipiravir, pro který jsme na základě interakce s nízkoenergetickými elektrony potvrdili jeho radiosensitizační potenciál. Také byl zkoumán mechanismus radiosensitizace již potvrzeného radiosensitizéru a zároveň chemoterapeutika RRx-001 z pohledu jeho možné interakce se sekundárními nízkoenergetickými elektrony, která byla v této práci potvrzena. Nakonec byla odhalena silná interakce solvatovaných elektronů s fullerenoly studovanými pro použití v rámci platformy, která by prokazovala citlivost na nízkoenergetické elektrony a užívala by se pro dodávání léků v rámci konkomitantní chemoradiační terapii

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Coupier, Bruno. "Studies towards the understanding of the effects of ionizing radiations at the molecular scale : (20-150 ke V H+/H + He collisions ; dissociative Electron attachment to water)". Lyon 1, 2005. http://tel.archives-ouvertes.fr/docs/00/06/43/27/PDF/thesecoupier.pdf.

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Ce travail s'inscrit dans le cadre d'études récentes pour la compréhension à l'échelle moléculaire des effets des rayonnements ionisants sur les systèmes biologiques, mises en oeuvre par le groupe IPM de l'IPNL en collaboration avec l'Institut für Ionenphysik de l'Université d'Innsbruck. Il est composé de deux parties. La première présente un nouvel ensemble de mesures des sections efficaces d'ionisation de l'hélium par impact de protons ou d'atomes d'hydrogène dans la gamme d'énergie d'intérêt pour la radiobiologie (20 à 150keV). Il s'agit de systèmes modèles d'intérêt pour la compréhension des phénomènes de base, et les collisions H + He ont fait l'objet, jusqu'à présent, de peu d'études utilisant les techniques de coïncidences. En outre, cette étude avec l'hélium a été faite dans l'intention de réaliser un test général de fonctionnement de l'appareillage avant d'aller vers des systèmes plus complexes. Des études similaires ont été ensuite réalisées en remplaçant la cible d'hélium par l'eau ou par des molécules d'intérêt biologique (Uracil, Thymine. . . ). La seconde partie de la thèse traite d'un autre type de radiations ionisantes que l'on peut voir comme une des conséquences secondaires des radiations étudiées dans la première partie. Des électrons de faible énergie (1 à 16eV) sont émis lors du bombardement de la matière par des protons ou des atomes d'hydrogène rapides; ces électrons ayant à leur tour des effets ionisants sur l'environnement. Une étude de l'attachement dissociatif des électrons sur l'eau a été entreprise à l'université d'Innsbruck, motivée par l'existence d'importants désaccords entre les précédentes études sur le même sujet. Le problème de la discrimination des ions à grande énergie cinétique dans le monochromateur trochoïdal utilisé pour cette étude a fait l'objet d'une attention particulière

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Coupier, Bruno Farizon Michel Märk Tilmann. "Studies towards the understanding of the effects of ionizing radiations at the molecular scale (20-150 ke V H+/H + He collisions ; dissociative Electron attachment to water) /". Villeurbanne : Université Claude Bernard, 2005. http://tel.archives-ouvertes.fr/docs/00/06/43/27/PDF/thesecoupier.pdf.

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Reproduction de : Thèse de doctorat : Physique nucléaire : Lyon 1 : 2005. Reproduction de : Thèse de doctorat : Physique nucléaire : Innsbruck (Autriche) : 2005.
Thèse soutenue en co-tutelle. Thèse en anglais. Titre provenant de l'écran titre. 98 réf. bibliogr.

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Wang, Chunrong. "REAL-TIME OBSERVATION OF MOLECULAR REACTION MECHANISM OF HALOPYRIMIDINES AS RADIO-/PHOTOSENSITIZING DRUGS USING TIME-RESOLVED FEMTOSECOND LASER SPECTROSCOPY". Thesis, 2007. http://hdl.handle.net/10012/3067.

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Replacement of thymidine in DNA by halopyrimidines, such as bromodeoxyuridine (BrdU) and iododeoxyuridine (IdU), has long been known to enhance DNA damage and cell death induced by ionizing/UV radiation, but the mechanism of action of halopyrimidines at the molecular level is poorly understood. We have applied advanced time-resolved femtosecond laser spectroscopy to this molecular system of biological, chemical and medical significance. We obtained the first real-time observations of the transition states of the ultrafast electron transfer (UET) reactions of halopyrimidines with the ultrashort-lived precursor to the hydrated electron, which is a general product in ionizing/UV radiation. Our results provide a mechanistic understanding of these photo-/radiosensitizing drugs at the molecular level. We found that the UET reaction of BrdU is completed within 0.2 picosecond (ps) after the electronic exciataion, leading to the formation of the transition state BrdU* with a lifetime of ~1.5 ps that then dissociates into Br and a high reactive radical dU•. We have also demonstrated that the reaction efficiency for the formation of the reactive radical dU• to cause DNA damage and cell death is in the order of IdU>>BrdU>CldU>>FdU. This is due to the availability of two precursor states of ~0.2 ps and ~ 0.54 ps lifetimes for dissociative electron attachment (DEA) to IdU, of one precursor state of ~0.2 ps lifetime for DEAs to BrdU and CldU, and no precursors for DEA to FdU. This explains why BrdU and IdU were found to be effective radio-/photosensitizers and indicates that IdU should be explored as the most effective radiosensitizer among halopyrimidines. Moreover, as a by-product of this project, these halopyrimidines have been employed as quantum-state-specific molecular probes to resolve a long-standing controversy about the nature and lifetimes of prehydrated electrons. These findings also have a broader significance as they indicated that nonequilibrium precursor electrons may play an important role in electron-initiated reactions in many biological, chemical and environmental systems. We have also demonstrated UET reactions of nucleotides with the precursor to the hydrated electrons. Our results indicate that among DNA bases, adenine is the most efficient electron trapper and an effective electron transfer promoter, while guanine is the most effective in dissociative electron attachment. These results not only primarily explain the sequence selectivity of duplex DNA containing BrdU/IdU, but imply that the DEA of guanine is an important mechanism for radiation-induced DNA damage in ionizing radiation and radiotherapy of cancer.

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Libri sul tema "Electron attachment spectroscopy"

Graupner, R., e F. Hauke. Functionalization of single-walled carbon nanotubes: Chemistry and characterization. A cura di A. V. Narlikar e Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533046.013.16.

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This article examines the chemical functionalization and structural alteration of single-walled carbon nanotubes (SWCNTs). It describes the covalent functionalization of the SWCNT framework that is the covalent attachment of functional entities onto the CNT scaffold. In particular, it considers the chemical modification and reactivity of SWCNTs in the context of the reactivity of graphite and fullerenes. It also discusses the defect and sidewall functionalization of SWCNTs, along with various techniques used in the characterization ofSWCNTs upon functionalization, namely: thermogravimetric analysis, spectroscopic techniques such as UV-Vis-NIR spectroscopy and Raman spectroscopy, and microscopic techniques like transmission electron microscopy, atomic force microscopy and scanning tunnelling microscopy.

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Capitoli di libri sul tema "Electron attachment spectroscopy"

Illenberger, Eugen, e Jacques Momigny. "Electron Attachment Spectroscopy". In Topics in Physical Chemistry, 264–98. Heidelberg: Steinkopff, 1992. http://dx.doi.org/10.1007/978-3-662-07383-4_10.

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Loureiro, Jorge, e Jayr Amorim. "Electron Transport, Ionization and Attachment". In Kinetics and Spectroscopy of Low Temperature Plasmas, 191–231. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-09253-9_5.

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Illenberger, Eugen, e Jacques Momigny. "Negative Ions Observed in Electron Transmission and Electron Attachment Spectroscopy". In Topics in Physical Chemistry, 299–310. Heidelberg: Steinkopff, 1992. http://dx.doi.org/10.1007/978-3-662-07383-4_11.

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"The Wide-angle Toroidal Energy Analyzer Attachment". In Secondary Electron Energy Spectroscopy in the Scanning Electron Microscope, 83–123. WORLD SCIENTIFIC, 2020. http://dx.doi.org/10.1142/9789811227035_0002.

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Hsine, Zouhour, e Rym Mlika. "Novel Sensor Based on Nanocarbon Transducer Functionalized by Iron (III) Porphyrin for the Impedimetric Detection of Bisphenol A". In Bisphenols [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98560.

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In this chapter, an impedimetric response of iron (III) porphyrin (Fe(III)TMPP) functionalized on gold transducer towards the detection of three phenolic compounds entitled bisphenol A (BPA), 2,2′-biphenol and catechol has been studied. The bisphenol A that has revealed the best affinity with Fe(III)TMPP membrane has been chosen as the target analyte. For improved sensitivity of Au/Fe(III)TMPP sensor towards BPA, a facile and efficient Au/RGO nanocarbon transducer based on reduced graphene oxide (RGO) has been prepared and used to support Fe(III)TMPP membrane. The obtained Au/RGO/Fe(III)TMPP structure was characterized by UV–visible (UV–vis) and electrochemical impedance spectroscopy (EIS) measurements, then applied as electrochemical platform for BPA detection. It has been discovered that the Au/RGO nanocarbon transducer has an amplified electron transfer kinetic compared to unmodified Au transducer. The Au/RGO/Fe(III)TMPP structure has showed a better affinity towards BPA with a doubled sensitivity compared to that obtained with Au/Fe(III)TMPP electrode. We demonstrated that the Au/RGO nanocarbon transducer not only enhances the electron transfer ability but also serves as a good template for the attachment of Fe(III)TMPP throughπ-π interaction. This study reveals new high-potential of nanocarbon transducer based on RGO for the conception of electrochemical sensors with high sensitivity and short response time.

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Kausar, Samia, Ataf Ali Altaf, Muhammad Hamayun, Amin Badshah e Abdul Razzaq. "Supramolecular Chemistry and DNA Interaction Studies of Ferrocenyl Ureas and Thioureas". In Photophysics, Photochemical and Substitution Reactions- Recent Advances [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.84412.

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In this chapter, we have discussed the characteristics and bioapplicabilities of different ferrocene derivatives, for example, amides, amines, sulfonamide, and polymers, focusing mainly on urea and thiourea derivatives due to their autonomous and widespread spectroscopic action and bioactivities. Supramolecular chemistry of ferrocenyl ureas and thioureas is described owing to exploring their mode of interactions within and among the molecules and the role of these supramolecular structures in enhancing the DNA intercalation. DNA interaction studies of these ferrocenyl-based ureas and thioureas are explored with approaches like electrochemical study, viscosity measurements, molecular docking, electronic spectroscopy, dynamic light scattering (DLS), and radical scavenging activity. Attachment of ferrocene moiety to ureas an thiouereas closer to DNA is very promising strategy which most possibly boosts the probability of DNA damage and cell apoptosis which is responsible for enormous biological activities.

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Atti di convegni sul tema "Electron attachment spectroscopy"

Böhm, Alexander, Melanie Gattermayer, Franz Carstens, Samuel Schabel e Markus Biesalski. "Designing Microfabricated Paper Devices through Tailored Polymer Attachment". In Advances in Pulp and Paper Research, Cambridge 2013, a cura di S. J. I’ Anson. Fundamental Research Committee (FRC), Manchester, 2013. http://dx.doi.org/10.15376/frc.2013.2.599.

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In the present paper we show that polystyrene–based copolymers, which carry a defined amount of photo–reactive benzophenone moities can be transferred and immobilized to paper substrates via a simple dip coating approach and subsequent illumination of the paper substrates with UV-light. Non-bound macromolecules can be removed from the cellulose fibers by solvent extraction. Thereby, the amount of immobilized polymer can be adjusted over a wide range by changing the polymer concentration in the dip coating solution. The resulting polymer-modified paper substrates were characterized using IR spectroscopy, scanning electron microscopy (SEM), fluorescence microscopy and static contact angle measurements. The polymers are attached to cellulose fibers using a photo–chemical approach and stable chemical micro patterns, including paper-defined microchannels, can be designed inside model paper substrates by using conventional UV-lithography. These channels are capable to control the fluid penetration by capillary actions. An engineering of the paper substrate itself allows to modulate the speed of the fluid transport of an aqueous solution inside paper-defined microchannels. The latter will become important for a number of applications.

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Gelabert, H., J. Belloni, J. L. Marignier e Y. Gauduel. "Femtosecond Electron Transfer and Real Time Discrimination of a Disulfide Bond Formation". In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.26.

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The aim of this experimental work is to discriminate, in real time, the first steps of a S-S bond formation in solution (figure 1). One electron reduction or oxidation of a simple thioether, the dimethylsulfide (CH3SCH3), has been investigated by femtosecond UV-IR spectroscopy. Indeed, when an electron of excess energy is injected in a liquid organic sulfide characterized by a high electron affinity, an irreversible electron attachment competes with the solvation process. This electron transfer yields a primary anion (RSR-, R = CH3) which exhibits a high reactivity through an ultrafast ion-molecule reaction. This contribution will focus mainly on S-S bridge formation triggered by a primary anion/cation-molecule reaction.

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Lall, Pradeep, Daniel Karakitie e Scott Miller. "Surface-Mount Component Attachment on Aerosol Jet Printed Sustainable Water-Base Silver Nanoparticle Ink". In ASME 2023 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/ipack2023-111957.

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Abstract Additive methods are preferred over processes that need hard tooling due to ramp-up speed and soft tooling. Increasing demand for the miniaturization of electronics has accelerated the development of flexible electronics technology. Flexible electronic architectures have gained traction in products for various end applications. The prior generation of additive processes used volatile organic solvent-based inks to fabricate printed circuits. Increased emphasis on environmental, social, and governmental factors has called attention to the development of sustainable products. Recent material development has seen the emergence of water-based inks with low-impact environmental waste. Sustainable inks use water as the carrier medium in place of volatile solvents. Owing to the recent introduction of these formulations, less is known about the ability to form functional circuits with sustainable inks or their performance relative to the incumbent non-sustainable volatile organic solvent-based inks. In this paper, Components were attached to additively printed water-based ink circuits fabricated using an aerosol jet. Interconnect methods have been studied, including — electrically conductive adhesives. The component performance of RLC has been studied as a function of operating frequency and compared with the rated values. Mechanical performance has been studied using the shear load to failure and electron dispersive x-ray spectroscopy. The electrical performance has been correlated with the mechanical performance and optical methods have also been used to characterize the results of the printed trace.

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Maharubin, Shahrima, Xiaomei Shu, Manavi Singh, Benildo De los Reyes e George Tan. "Surface Modifications of Titanium With Covalently-Bonded Silver Nanoparticles for Antimicrobial Applications". In ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2870.

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Abstract Formation of biofilm on implant surface is one of the major causes for port-operative infection. Incorporation of antimicrobial silver nanoparticles (AgNPs) on implant surface has been studied as an effective remedy in recent decades. This paper presents a novel AgNPs-titanium composite foil manufactured through covalent attachment of AgNPs for biofilm control. This composite foil was fabricated by a series of chemical reactions including thiol-derivatization and formation of Ag-S covalent bonds. The film structure and properties were characterized through scanning electron microscopy (SEM), Energy dispersive X-ray Spectroscopy (EDS) and surface profiling. The antimicrobial performance was examined against gram positive bacterial strain Staphylococcus aureus. Results indicate that the prepared composite foil effectively reduced bacterial attachment in short term exposure and possess high stability against the release of nanoparticles. This novel antimicrobial composite material has a great potential to be used in the future biomedical instrumentation.

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Lall, Pradeep, Daniel Karakitie e Scott Miller. "Additively Printed Circuits Using Biodegradable Substrates on Aerosol-Jet With Aqueous-Based Silver Conductive Paste Using ECA and Low-Temperature Interconnects". In ASME 2024 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/ipack2024-141879.

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Abstract Traditionally, the manufacture of printed circuits relied on volatile organic solvent-based inks, a practice now scrutinized due to growing environmental concerns. There’s a notable shift towards water-based inks, offering a reduced environmental footprint by replacing volatile solvents with water as the carrier medium. However, despite their promising attributes, the functionalities and performances of circuits created with these sustainable inks remain relatively unexplored compared to their non-sustainable counterparts. This study addresses this knowledge gap, focusing on the innovative use of biodegradable PET substrates in the aerosol jet printing process. The research includes a comprehensive analysis of circuits created with sustainable water-based inks, with a specific focus on their application on biodegradable PET substrates. Key components were attached to these circuits using electrically conductive adhesives and low-temperature adhesives to compare the various effects of interconnects on the component attachment and the performance of the circuit using these interconnect adhesive materials. The evaluation involved a detailed analysis of component performance, particularly RLC components, in relation to operating frequency, and electron dispersive x-ray spectroscopy analysis. Extensive testing was performed to delineate the electrical and mechanical properties of the resulting circuits, with a specific focus on resistance values across varying sintering temperatures and durations. Preliminary findings indicate that modifying these parameters can enhance electrical properties, and optical methods were employed to characterize the printed trace outcomes.

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Hubbard, William A., Ho Leung Chan e B. C. Regan. "High-Resolution Conductivity Mapping with STEM EBIC". In ISTFA 2022. ASM International, 2022. http://dx.doi.org/10.31399/asm.cp.istfa2022p0251.

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Abstract Modern electronic systems rely on components with nanometer-scale feature sizes in which failure can be initiated by atomic-scale electronic defects. These defects can precipitate dramatic structural changes at much larger length scales, entirely obscuring the origin of such an event. The transmission electron microscope (TEM) is among the few imaging systems for which atomic-resolution imaging is easily accessible, making it a workhorse tool for performing failure analysis on nanoscale systems. When equipped with spectroscopic attachments TEM excels at determining a sample’s structure and composition, but the physical manifestation of defects can often be extremely subtle compared to their effect on electronic structure. Scanning TEM electron beam-induced current (STEM EBIC) imaging generates contrast directly related to electronic structure as a complement the physical information provided by standard TEM techniques. Recent STEM EBIC advances have enabled access to a variety of new types of electronic and thermal contrast at high resolution, including conductivity mapping. Here we discuss the STEM EBIC conductivity contrast mechanism and demonstrate its ability to map electronic transport in both failed and pristine devices.

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Ghazanfari, Amir, Wenbin Li, Ming C. Leu, Jeremy Watts, Yiyang Zhuang e Jie Huang. "Freeform Extrusion Fabrication of Advanced Ceramic Components With Embedded Sapphire Optical Fiber Sensors". In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9270.

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Traditionally, sensors to be integrated into a structural component are attached to or mounted on the component after the component has been fabricated. This tends to result in unsecured sensor attachment and/or serious offset between the sensor reading and the actual status of the structure, leading to performance degradation of the host structure. This paper describes a novel extrusion-based additive manufacturing process that has been developed to enable embedment of sensors in ceramic components during the part fabrication. In this process, an aqueous paste of ceramic particles with a very low amount of binder content (< 1 vol%) is extruded through a moving nozzle to build the part layer-by-layer. In the case of sensor embedment, the fabrication process is halted after a certain number of layers have been deposited. The sensors are placed in their predetermined locations, and the remaining layers are deposited until the part fabrication is completed. Because the sensors are embedded during the fabrication process, they are fully integrated with the part and the aforementioned problems of traditional sensor embedment can be eliminated. The sensors used in this study were made of sapphire optical fibers of 125 and 250 micro-meters diameter and can withstand temperatures up to 1600 °C. After the parts were built, two different drying processes (freeze drying and humid drying) were investigated to dry the parts. The dried parts were then sintered to achieve near theoretical density. Scanning electron microscopy was used to observe the embedded sensors and to detect any possible flaws in the part or embedded sensor. Attenuation of the sensors was measured in near-infrared region (1500–1600 nm wavelength) with a tunable laser source. Raman spectroscopy was performed on the samples to measure the residual stresses caused by shrinkage of the part and its slippage on the fibers during sintering and mismatch between the coefficients of thermal expansion of the fiber and host material. Standard test methods were employed to examine the effect of embedded fibers on the strength and hardness of the parts. The result indicated that the sapphire fiber sensors with diameters smaller than 250 micrometers are able to endure the freeform extrusion fabrication process and also the post-processing without compromising the part properties.

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Zhang, Xudong, Anis Nurashikin Nordin, Fang Li e Ioana Voiculescu. "STRETCHABLE Lab-on-Chip Device With Impedance Spectroscopy Capability for Mammalian Cell Studies". In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66156.

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This paper presents the fabrication and testing of electric cell-substrate impedance spectroscopy (ECIS) electrodes on a stretchable membrane. This is the first time when ECIS electrodes were fabricated on a stretchable substrate and ECIS measurements on mammalian cells exposed to cyclic strain of 10% were successfully demonstrated. A chemical was used to form strong chemical bond between gold electrodes of ECIS sensor and polymer membrane, which enable the electrodes keep good conductive ability during cyclic stretch. The stretchable membrane integrated with the ECIS sensor can simulate and replicate the dynamic environment of organism and enable the analysis of the cells activity involved in cells attachment and proliferation in vitro. Bovine aortic endothelial cells (BAEC) were used to evaluate the endothelial function influenced by mechanical stimuli in this research because they undergo in vivo cyclic physiologic elongation produced by the blood circulation in the arteries.

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Usmanov, R. A., A. D. Melnikov, V. P. Polistchook e S. B. Vetrova. "Diffuse vacuum arc discharge with heated cathode made of mixture of ceramic and metal powders". In 8th International Congress on Energy Fluxes and Radiation Effects. Crossref, 2022. http://dx.doi.org/10.56761/efre2022.c1-o-043402.

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The paper present results of an experimental study of a plasma flow parameters generated by a vacuum arc discharge with heated cathode made of mixture of ceramic and metal powders. The discharge existed in a diffuse mode of cathode current attachment. The diffuse mode was characterized by relatively low values of cathode current density (10–100 A/cm 2 ), absence of significant voltage oscillations and stable glow of plasma formation. The data on mean charge of the arc plasma flux, ion energies and ion composition measured by time-of-flight mass spectroscopy method were obtained. It was shown that chromium is a main source of the plasma forming medium when cerium dioxide is a main source of electrons of thermionic emission. Obtained results can be useful in designing of stable plasma sources of multi-component condensed substances for wide range of applications from deposition of composite coatings to plasma mass separation.

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Lin, Ying-Ting, Iren Kuznetsova e Gou-Jen Wang. "Genetically Modified Soybean Detection Using a Biosensor Electrode With Self-Assembled Gold Nanoparticles on a Micro Hemisphere Array". In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97112.

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Abstract Gene transfer technology changes some of the characteristics of crops. However, genetically modified foods have been reported to have an impact on human health. We proposed a cost effective and highly sensitive biosensor electrode with self-assembled monolayer of gold nanoparticle on a micro hemisphere array to detect genetically modified soybean. An ordered array of micro hemispherical features was formed on a 6-inch reclaimed silicon wafer using photolithography. Then, a thin gold layer was sputtered onto the hemispheres. The wafer was then immersed into a 5 mM ethanol solution of 1,6-hexanedithiol (1,6-HDT) to enable the attachment of one thio-end of 1,6-HDT to the thin gold layer. Next, a colloidal gold (15 nm) solution was dripped onto the wafer and baked on a hot plate in such a way that the monolayer of gold nanoparticles could self-assemble on the 1,6-HDT surface. Finally, we used electrochemical impedance spectroscopy (EIS) analysis to detect genetically modified soybean. Experimental results demonstrate that our biosensor can successfully distinguish the genetically modified soybeans from the normal ones.

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