Thematische Bibliographien / Helical Dichroism

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Auswahl der wissenschaftlichen Literatur zum Thema „Helical Dichroism“

Autor: Grafiati

Veröffentlicht am 30. Juni 2021

Zuletzt aktualisiert am 2. Februar 2022

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Zeitschriftenartikel zum Thema "Helical Dichroism"

Xie, Yun Zhi, Chun Hua Liu, Xun Li, Yi Bao Li und Xiao Lin Fan. „Asymmetry-Induced Supramolecular Helices of Pyrene-Perylene Bisimide Triads“. Advanced Materials Research 472-475 (Februar 2012): 462–65. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.462.

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The formation of helical nanostructure is investigated for donor/acceptor system. The helices of the supramolecular nanofibres can be revealed by atom force microscope (AFM) and circular dichroism (CD) measurement. The expermental results show the Py-Per-Py can self assembly into helical nanofibres. The controlled experiments on the compound Py-e-Per-e-Py with symmetrical conformation indicates the formation of helical nanofibres may be attributed to asymmetrical conformation.

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Miles, A. J., und B. A. Wallace. „Circular dichroism spectroscopy of membrane proteins“. Chemical Society Reviews 45, Nr. 18 (2016): 4859–72. http://dx.doi.org/10.1039/c5cs00084j.

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Liu, Yong, Chao Li, Yaling Liu und Zhiyong Tang. „Helical silver(I)-glutathione biocoordination polymer nanofibres“. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, Nr. 2000 (13.10.2013): 20120307. http://dx.doi.org/10.1098/rsta.2012.0307.

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Helical nanofibres of silver(I)-glutathione (Ag-GSH) biocoordination polymer (BCP) are fabricated by introducing dimethyl sulfoxide into the mixture solution of Ag + ions and l -GSH molecules. The prepared BCP nanofibres show hierarchical helical structures, which are constructed via twisting of small fibres. Water-soluble helices could be further cross-linked with Ca 2+ ions to form a well-dispersed aqueous suspension. When gold nanorods are adsorbed onto these helical nanofibres, the unique plasmon-induced circular dichroism characteristic is observed in the region of the local surface plasmon resonance of gold nanorods. This type of chiroptical metamaterials may have promising applications in nonlinear optics, negative refraction and biosensing.

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Daly, Steven, Frédéric Rosu und Valérie Gabelica. „Mass-resolved electronic circular dichroism ion spectroscopy“. Science 368, Nr. 6498 (25.06.2020): 1465–68. http://dx.doi.org/10.1126/science.abb1822.

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DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.

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Kaschke, Johannes, und Martin Wegener. „Optical and Infrared Helical Metamaterials“. Nanophotonics 5, Nr. 4 (01.09.2016): 510–23. http://dx.doi.org/10.1515/nanoph-2016-0005.

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AbstractBy tailoring metamaterials with chiral unit cells, giant optical activity and strong circular dichroism have been achieved successfully over the past decade. Metamaterials based on arrays of metal helices have revolutionized the field of chiral metamaterials, because of their capability of exhibiting these pronounced chiro-optical effects over previously unmatched bandwidths. More recently, a large number of new metamaterial designs based on metal helices have been introduced with either optimized optical performance or other chiro-optical properties for novel applications.The fabrication of helical metamaterials is, however, challenging and even more so with growing complexity of the metamaterial designs. As conventional two-dimensional nanofabrication methods, for example, electron-beam lithography, are not well suited for helical metamaterials, the development of novel three-dimensional fabrication approaches has been triggered.Here, we will discuss the theory for helical metamaterials and the principle of operation. We also review advancements in helical metamaterial design and their limitations and influence on optical performance. Furthermore, we will compare novel nano- and microfabrication techniques that have successfully yielded metallic helical metamaterials. Finally, we also discuss recently presented applications of helical metamaterials extending beyond the use of far-field circular polarizers.

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Ala, Paul, Pele Chong, Vettai S. Ananthanarayanan, Neville Chan und Daniel S. C. Yang. „Synthesis and characterization of a fragment of an ice nucleation protein“. Biochemistry and Cell Biology 71, Nr. 5-6 (01.05.1993): 236–40. http://dx.doi.org/10.1139/o93-036.

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Synthetic peptides were used as models for studying the conformation of ice nucleation proteins. We chemically synthesized four peptides (16-, 24-, 32-, and 48-mer) that consisted of two to six repeats of the consensus repeating octapeptide unit of ice nucleation proteins and evaluated their conformation by circular dichroism spectroscopy. These model peptides exist predominantly as random coils in aqueous solution, but adopt α-helical structures in the presence of trifluoroethanol. The stability of their secondary structures was investigated by monitoring the pH and time dependence of their circular dichroism spectra. Our results indicated that the α-helical content of the 48-mer exhibited a significant pH dependence, while that of the 24- and 32-mer peptides did not. The 32-mer was the only peptide that transformed from the α-helical to a β-sheet structure upon storage. We suggest that the overall conformation of the ice nucleation protein could be a β-sheet.Key words: ice nucleation protein, synthetic peptides, circular dichroism.

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Axelsen, P. H., B. K. Kaufman, R. N. McElhaney und R. N. Lewis. „The infrared dichroism of transmembrane helical polypeptides“. Biophysical Journal 69, Nr. 6 (Dezember 1995): 2770–81. http://dx.doi.org/10.1016/s0006-3495(95)80150-5.

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Rabenold, David A. „Circular dichroism band shapes for helical polymers“. Journal of Physical Chemistry 92, Nr. 17 (August 1988): 4863–68. http://dx.doi.org/10.1021/j100328a013.

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Kodaka, Masato. „Circular dichroism induced by helical host molecules“. Journal of the Chemical Society, Faraday Transactions 93, Nr. 11 (1997): 2057–59. http://dx.doi.org/10.1039/a700222j.

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Kaerkitcha, N., und T. Sagawa. „Amplified polarization properties of electrospun nanofibers containing fluorescent dyes and helical polymer“. Photochemical & Photobiological Sciences 17, Nr. 3 (2018): 342–51. http://dx.doi.org/10.1039/c7pp00413c.

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Well-aligned nanofibers containing cationic fluorescent dyes and anionic chiral polymers prepared via electrospinning exhibit an enhanced circular dichroism, which is mainly caused by linear dichroism and linear birefringence.

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Dissertationen zum Thema "Helical Dichroism"

Yang, Lin. „Interaction of molecules and helical nanoparticles characterized by electronic circular dichroism“. HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/523.

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It is of fundamental significance to differentiate an enantiomer from its mirror image (i.e., enantiodifferentiation), through monitoring optical activity (OA) of enantiomers that is typically characterized by electronic circular dichroism (ECD or CD) in the UV-visible region. However, sub-wavelength molecular dimensions substantially prevent enantiomers from effectively perceiving the different circular polarization states, leading to low enantiomeric OA and weak enantiodifferentiation. Some approaches have been developed to amplify the enantiomeric OA; alternatively, on the basis of the emerging chiral metamaterials of metallic helical nanoparticles (HNPs) I devise two methods to enhance the enantiodifferentiation. First, I employ glancing angle deposition (GLAD) to deposit Ag HNPs with a helical pitch (P) larger than wire diameter (d) of the helical, i.e., Ag nanohelices (AgNHs). AgNHs exhibit strong plasmonic CD composed of a broadband longitudinal mode (i.e., L-mode) in the visible region, a transverse mode (i.e., T-mode) at a wavelength of ~370 nm, and a dielectric mode in the deep UV region (at a wavelength shorter than 320 nm). Adsorption of alkyl ligands on the AgNHs markedly weakens the two plasmonic CD modes, and the T-mode is weakened more seriously than the L-mode. The deterioration of the plasmonic CD is exacerbated with increasing the bonding energy of the Ag-alkyl ligand contacts, attributed to the increase of the dielectric constant of the medium of the AgNHs (Îµr) and the electron withdrawal from the AgNHs towards the alkyl ligands. Derived from the ligand-induced weakening of the plasmonic CD, enantiodifferentiation of L-Glutathione (L-GSH) from D-GSH is dramatically enhanced. The chiroptical weakening sensitively varies with the absolute configuration of GSH, resulting in an enantiodifferentiation anisotropic g factor of ~0.5 that is independent on the AgNH helicity. The AgNH-induced anisotropy g factor is superior to those obtained by other methods, by 2 - 4 orders of magnitude. It is the largest achieved up-to-date, as high as one-fourth of the theoretical maximum. Second, I operate GLAD with fast substrate rotation to reduce P less than d, to generate AgHNPs that exhibit negligible dielectric CD in the deep UV region, offering a helical substrate to directly amplify the OA of enantiomers grafted on the AgHNPs. The anchoring of enantiomers on AgHNPs with the sub-5 nm P leads to the enantioselective amplification of the enantiomeric OA in roughly ten folds; the LH- and RH-AgHNPs give rise to amplify the OA of (S)- and (R)-enantiomers, respectively. It is ascribed to the change of the dihedral angle of an enantiomer adsorbed on AgHNPs. Such the enantioselective amplification tends not to occur as long as P > 5 nm. Moreover, given the enantiodifferentiation of biomolecules that are typically dissolved in an aqueous solution, the effect of water on the plasmonic CD of AgHNPs is investigated and compared with that of AgNHs. Hydrophobic AgNHs with high structural porosity give rise to the irreversible water effect on the plasmonic CD; and hydrophilic AgHNPs with low structural porosity lead to the reversible water effect. At the end, I devise a new methodology to generate plasmonic CD through chirality transfer from chiral host to achiral guest, owing to the helicity duplication of the achiral guest from the chiral host. It leads to inducing chiroptical activity of the achiral guest made of some plasmonic materials that aren't facilely sculptured in the helical. The new methodology effectively broadens the range of materials made from the chiral nanostructures, which is on demand to develop diverse chirality-related bioapplications.

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Strong, Andrew Edward. „Self-assembling monolayers of helical oligopeptides with applications in molecular electronics“. Thesis, University of Strathclyde, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366950.

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Takeda, Ryohei. „Effect of Chiral Solvent and Pressure on the Dynamic Screw-Sense Induction to Poly(quinoxaline-2,3-diyl)s“. Kyoto University, 2017. http://hdl.handle.net/2433/227637.

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Rahimiangolkhandani, Mitra. „Interaction of Structured Femtosecond Light Pulses with Matter“. Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42334.

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Physics and potential applications of femtosecond laser pulses interacting with matter have captured interest in various fields, such as nonlinear optics, laser micromachining, integrated optics, and solar cell technologies. On the one hand, such ultrashort intense pulses make them practical elegant tools to be utilized for direct structuring of materials with high accuracy and numerous potential applications. On the other hand, studying the fundamental aspects and nonlinear nature of such interactions opens new remarkable venues for various unique investigations. In recent years, the emerging topic of structured light (also known as twisted or optical vortex light), i.e., a beam of light with a twisted wave-front that can carry orbital angular momentum (OAM), has attracted the attention of many researchers working in the field of light-matter interaction. Such beams offer various applications from classical and quantum communication to imaging, micro/nano-manipulation, and modification of fundamental processes involved in light-matter interactions, e.g., absorption and emission. Nevertheless, the fabrication of complex structures, controlled modification, and achieving a high spatial resolution in material processing still remain in the spotlight. Moreover, the fundamental role of orbital angular momentum in the nonlinear absorption of materials, particularly in solids, has yet remained a subject of debate. Addressing these points was the main motive behind this dissertation. To accomplish this objective and investigate new aspects of structured light-matter interaction, I conducted various experiments, the results of which are presented in this work. The general idea was to study the interaction of femtosecond laser radiation, having a structured phase and polarization, with the matter in two aspects: (i) surface morphology modification and (ii) nonlinear absorption of solids. In this regard, I studied surface processing of crystalline silicon and CVD diamond with femtosecond laser vortex pulses generated by a birefringent phase-plate, known as q-plate, in single and multiple pulse irradiation regimes, respectively. The characterization of the modified region was performed using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). I demonstrated that upon irradiation of a single vortex pulse on silicon, a nano-cone structure is formed within the ablated crater, whose height was independent of the helicity of the twisted light. However, for a linearly polarized vortex pulse, the height of the nano-cone decreases at higher pulse energies. The dynamics of nano-cone formation and the role of polarization were also investigated by simulating the mass transport function in this process. Moreover, using superimposed vortex beams, we fabricated complex patterns containing several nano-cones, by single-shot irradiation on the silicon surface. My experimental results offer an ability to actively control and manipulate material, in terms of the nanocones position, in two dimensions with an ultra-high resolution. I further proceeded with our experiments in the multiple pulse regime on a diamond target. By irradiation of a high number of superimposed vortex pulses, I was able to imprint complex polarization states of structured light on the target surface in the form of periodic nano-ripples. This procedure enabled us to not only generate spatially varying nano-gratings but also directly visualize and study very complex states of polarization. Besides these surface structuring, I carried out experimental studies to investigate the response of bulk material to an incident circularly polarized vortex beam that carries orbital angular momentum. The experimental results reveal, for the first time, that such an interaction can produce a differential absorption that gives rise to helical dichroism. We demonstrate that this response is sensitive to the handedness and degree of the twist in the incident vortex beam. Such a dichroism effect may be attributed to the excitation of dipole-forbidden atomic transitions, e.g., electric quadrupole transitions. However, this explanation is not absolute and remains open to further research and investigations.

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Kato, Kenichi. „Development of Fused Porphyrins with Unpaired Electrons and/or Chirality“. Kyoto University, 2020. http://hdl.handle.net/2433/253108.

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Taboury, Jean. „Etude des conformations en double hélice droite et en double hélice gauche d'ADN synthétiques par plusieurs techniques spectroscopiques“. Paris 13, 1985. http://www.theses.fr/1985PA132021.

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Adam, Safia. „Etude des conformations secondaires d'ADN synthétiques pas spectrométrie optique“. Paris 13, 1985. http://www.theses.fr/1985PA132001.

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Pathan, Shaheen. „Développement de matériaux flexibles optiquement actifs basés sur des nanostructures hybrides chirales de modèle d’assemblage moléculaire“. Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0126.

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Dans ce travail, nous nous sommes concentrés sur la création de nanostructures chirales optiquement actives en fabriquant des nanohélices de silice fluorescente afin d’obtenir des matériaux souple, nanométriques, optiquement actifs pour des applications en tant que matériaux nanophotoniques. Dans cette optique, des nanohélices de silice chirales ont été utilisées pour greffer et organiser des nanocristaux inorganiques fluorescents achiraux tels que des quantums dots, des chromophores, des molécules et des polymères fluorescents selon différentes approches. Ces hélices inorganiques ont été formées par procédé sol-gel en utilisant des auto-assemblages hélicoïdaux organiques de molécules amphiphiles (amphiphile gemini cationique, avec un contre-ion chiral le tartrate) en tant que modèles. Tout d'abord, la surface de la silice hélicoïdale a été fonctionnalisée par l’APTES afin de greffer des quantum dots inorganiques ZnS-AgInS2 possédant divers ligands. Dans la deuxième partie, le polymère de dérivé anthracénique fluorescent a été organisé par dépôt et adsorption à la surface de silice hélicoïdale. Afin d’étudier les propriétés chiroptiques, différentes caractérisations ont été réalisées telle que la spectroscopie du dichroïsme circulaire (CD) et celle de la luminescence circulairement polarisée (CPL).Le premier chapitre présente l’étude bibliographique sur différents systèmes d’auto-assemblage organiques chiraux et leurs propriétés chiroptiques. Les études sur la formation de systèmes auto-assemblés chiraux dans différentes conditions, leur morphologie structurale, les techniques de fabrication et leurs applications sont discutées suivies de l'utilisation de nanocristaux fluorescents, à savoir, les quantums dots (QD) et les polymères fluorescents achiraux sur lesquels les propriétés chiroptiques peuvent être obtenues et leurs applications dans les nanodispositifs optiques, les capteurs et la nano-photonique.Dans la première partie du deuxième chapitre, différentes techniques de caractérisation telles que le microscope électronique en transmission (TEM), le microscope électronique en transmission haute résolution (HRTEM), la microscopie confocale, la spectroscopie UV-Vis, celle de la fluorescence, du dichroïsme circulaire (CD) et de la luminescence circulairement polarisée (CPL) sont décrites. Dans la deuxième partie, la synthèse du gemini 16-2-16 ainsi que son mécanisme d'auto-assemblage, et sa transformation en réplica de silice par l'intermédiaire de la chimie sol-gel sont décrits. Ces nanohélices de silice sont fonctionnalisées par le 3-aminopropyltriéthoxysilane (APTES). Leur analyse est effectuée par analyse thermogravimétrique (TGA) et analyse élémentaire (EA).Dans le troisième chapitre, nous nous sommes concentrés sur la synthèse de QDs inorganiques ((ZnS)x-1(AgInS2)x) avec différentes compositions rapport molaire et leurs caractérisations par TEM, TGA, EA, spectroscopie infrarouge à transformée de Fourier (FTIR), mesures de potentiel zêta, spectroscopie d'absorption et d'émission. Quatre types de ligands ont été utilisés, par échange de ligand, pour recouvrir les QDs : sulfure d'ammonium (AS), acide 3-mercaptopropionique (MPA), l-cystéine (L-Cys) et l'oleylamine (OLA). Ces QDs sont greffés à la surface des hélices de silice modifiée par de l’amine suite à des interactions ioniques. Diverses techniques ont été utilisées pour confirmer leur greffage à la surface des hélices de silice, et les propriétés optiques ont été étudiées par spectroscopie d'absorption et d'émission. Après le greffage, différents résultats ont été observés selon le ligand utilisé : la caractérisation par TEM montre que les QDs sont greffés à la surface des hélices de silice. [...]
In this work, we focused on the creation of optically active chiral nanostructures by fabricating fluorescent silica nanohelices in order to obtain optically active nanoscale soft materials for applications as nanophotonics materials. For this purpose, silica chiral nanohelices were used for grafting and organizing achiral fluorescent inorganic nanocrystals, dyes, molecules, and fluorescent polymers through different approaches. These inorganic helices were formed via sol-gel method using organic helical self–assemblies of surfactant molecules (achiral and cationic gemini surfactant, with chiral counterion, tartrate) as templates. First, the surface of helical silica was functionalized by APTES in order to graft inorganic quantum dots ZnS-AgInS2 with different capping ligands. In the second part, fluorescent anthracene derivative polymer was organized via deposition and absorption on the surface of helical silica. To investigate the chiroptical properties, circular dichroism and circularly polarised luminescence characterization were performed.In the first chapter, the bibliographic study on different chiral organic self-assembling systems and their chiroptical properties are shown. The studies on the formation of chiral self-assembled systems in different conditions, structural morphology, fabrication techniques and their applications are discussed followed by the use of fluorescent nanocrystals, i.e., quantum dots (QDs) and achiral fluorescent polymers on which chiroptical properties can be obtained and their applications in optical nanodevices, sensors, and nano-photonics.In the first part of the second chapter, different characterisation techniques such as transmission electron microscope (TEM) , high resolution transmission electron microscope (HRTEM), and confocal microscopy, UV-Vis spectroscopy and fluorescence spectroscopies, as well as circular dichroism (CD) and circularly polarised luminescence (CPL) spectroscopies are described. In the second part, the synthesis of Gemini 16-2-16 as well as their self-assemblies mechanism, and their transformation to silica replica via sol-gel chemistry are described. These silica nanohelices are functionalized by 3-aminopropyltriethoxysilane (APTES). Their analysis is performed by Thermogravimetric analysis (TGA) and elementary analysis (EA).In the third Chapter, we focused on the synthesis of inorganic ((ZnS)x-1(AgInS2)x) QDs with different compositions molar ratio and its characterizations by TEM, TGA, EA, Fourier-transform infrared spectroscopy (FTIR), zeta potential measurements, absorption, and emission spectroscopy. Four types of ligands were used to cap the QDs via phase ligand exchange as follows: ammonium sulphide (AS), 3-mercaptopropionic acid (MPA), l-cysteine (L-Cys) and the fourth one is oleylamine (OLA). These QDs are grafted on the surface of amine-modified silica helices through ionic interaction. Various techniques were used to show the grafting of QDs on the surface of silica helix, and their optical properties were studied using absorption and emission spectroscopy. After grafting, in each case of ligands, different results were observed as follows: The TEM characterization shows that QDs are grafted on the surface of silica helices. In the case of AS-capped QDs, the helical morphology of silica helices after grafting is destroyed; therefore the further ananlysis was not possible. While, in the cases of QDs with three other ligands MPA, OLA and L-cys, dense and homogeneous grafting of the QDs were observed by TEM and the helical morphology was preserved after their grafting. The HRTEM images were taken on the MPA-QDs@silica helices and energy-dispersive x-ray (EDX) analysis was performed in STEM mode, confirming the QDs elements present on the silica surfaces. [...]

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Mangavel, Cécile. „Peptides amphiphiles hélicogènes : comportement en solution aqueuse et interaction avec des membranes modèles“. Orléans, 1996. http://www.theses.fr/1996ORLE2043.

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Les interactions entre peptides amphiphiles helicogenes et membranes jouent un role fondamental dans de nombreux mecanismes biologiques. D'une grande diversite de sequences primaires, ces peptides possedent la propriete commune d'adopter une structure secondaire d'helice alpha en presence de membranes. Il semble donc que ce soit cette structure secondaire qui gouverne reellement l'interaction membranaire. Au cours de ce travail, nous nous sommes interesses a des peptides modeles dont les sequences primaires alternent residus hydrophiles et hydrophobes afin de favoriser la formation d'helices alpha amphiphiles. Nous avons d'abord etudie la conformation des peptides en solution aqueuse. Majoritairement sous forme desordonnee dans l'eau pure, ils se structurent en helices alpha en solution saline, en raison de l'effet d'ecran du aux anions. Ces helices sont regroupees en agregats dont la cohesion est assuree par des interactions hydrophobes. A l'aide de la modelisation moleculaire, nous avons pu construire un modele pour ces structures, qui comprendraient entre 6 et 8 monomeres. Une etude cinetique a permis de proposer un mecanisme de formation des agregats. Nous nous sommes ensuite interesses a l'interaction peptides / vesicules phospholipidiques. Nous avons montre que ces peptides s'inserent dans la membrane sous forme d'helices alpha: cette insertion fait intervenir une attraction electrostatique ainsi qu'une interaction hydrophobe. Les helices sont alors monomeriques et orientees parallelement a la surface membranaire. En particulier, il faut noter que les complexes induits par la force ionique se dissocient en presence de membranes pour permettre l'insertion monomerique des helices dans la bicouche. Toutefois, l'insertion de l'helice provoque une importante perturbation des chaines phospholipidiques, les differentes molecules de phospholipides ancrees sur les residus lysine ne se trouvant pas dans un plan horizontal: il est donc impossible de definir precisement une profondeur d'insertion du peptide. Le nombre de phospholipides interagissant avec une helice serait de 25 environ

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Höger, Geralin. „Self-Organization of β-Peptide Nucleic Acid Helices for Membrane Scaffolding“. Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0003-C187-A.

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Buchteile zum Thema "Helical Dichroism"

Wang, Lijiang, Petr Pancoska und Timothy A. Keiderling. „Detection of Triple Helical Nucleic Acids with Vibrational Circular Dichroism“. In Fifth International Conference on the Spectroscopy of Biological Molecules, 81–82. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1934-4_27.

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Batchelor, Matthew, Marcin Wolny, Marta Kurzawa, Lorna Dougan, Peter J. Knight und Michelle Peckham. „Determining Stable Single Alpha Helical (SAH) Domain Properties by Circular Dichroism and Atomic Force Microscopy“. In Methods in Molecular Biology, 185–211. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8556-2_10.

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Fasman, Gerald D., Kyusung Park und Andras Perczel. „Distinguishing Transmembrane Helices from Peripheral Helices by Circular Dichroism“. In The Jerusalem Symposia on Quantum Chemistry and Biochemistry, 17–38. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2718-9_3.

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Fasman, Gerald D. „Differentiation between Transmembrane Helices and Peripheral Helices by the Deconvolution of Circular Dichroism Spectra of Membrane Proteins“. In Circular Dichroism and the Conformational Analysis of Biomolecules, 381–412. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4757-2508-7_10.

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Moore, Dexter S. „Circular Dichroism of Large Oriented Helices: A Free Electron on a Helix“. In Applications of Circularly Polarized Radiation Using Synchrotron and Ordinary Sources, 147–57. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4757-9229-4_14.

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Rodger, Alison, und Matthew A. Ismail. „Introduction to circular dichroism“. In Spectrophotometry and Spectrofluorimetry. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780199638130.003.0008.

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Circular dichroism (CD) is the ideal technique for studying chiral molecules in solution. It is uniquely sensitive to the asymmetry of the system. These features make it particularly attractive for biological systems. CD is by definition the difference in absorption, A, of left and right circularly polarized light (CPL): . . . CD = Ae − Ar . . . . . . 1 . . . CPL has the electric field vector of the electromagnetic radiation retaining constant magnitude in time but tracing out a helix about the propagation direction. Following the optics convention we take the tip of the electric field vector of right CPL to trace out a right-handed helix in space at any instant of time (1, 2). CD spectra can in principle be measured with any frequency of electromagnetic radiation. In practice, most CD spectroscopy involves the ultraviolet-visible (UV-visible) regions of the spectrum and electronic transitions, though increasing progress is being made with measuring the CD spectra of vibrational transitions using infrared radiation. We shall limit our consideration to electronic CD spectroscopy since the practical considerations for vibrational CD differ from those for electronic CD. For randomly oriented samples, such as solutions, a net CD signal will only be observed for chiral molecules (ones that cannot be superposed on their mirror images (3)). Oriented samples of achiral molecules, such as crystals, will also give a CD spectrum unless the optical axis of the sample aligns with the propagation direction of the radiation. However, such spectra are seldom useful. CD is now a routine tool in many laboratories. The most common applications include proving that a chiral molecule has indeed been synthesized or resolved into pure enantiomers and probing the structure of biological macromolecules, in particular determining the α-helical content of proteins. Figure 3 gives an example of a CD spectrum. The key points to remember are that a CD signal is observed only at wavelengths where the sample absorbs radiation, i.e. under absorption bands, and the signal may be positive or negative depending on the handedness of the molecules in the sample and the transition being studied.

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Hayashi, Nobuhiro, Mamoru Matsubara, Koiti Titani und Hisaaki Taniguchi. „Involvement of basic amphiphilic α-helical domain in the reversible membrane interaction of amphitropic proteins: Structural studies by mass spectrometry, circular dichroism, and nuclear magnetic resonance“. In Techniques in Protein Chemistry, 555–64. Elsevier, 1997. http://dx.doi.org/10.1016/s1080-8914(97)80055-5.

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Konferenzberichte zum Thema "Helical Dichroism"

Citra, Mario J., M. G. Paterlini, Teresa B. Freedman, Adriano Fissi und Osvaldo Pieroni. „Vibrational circular dichroism studies of 3 10 -helical solution conformers in dehydro-peptides“. In Fourier Transform Spectroscopy: Ninth International Conference, herausgegeben von John E. Bertie und Hal Wieser. SPIE, 1994. http://dx.doi.org/10.1117/12.166677.

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Muro, T. „A Measurement System For Circular Dichroism In Soft X-ray Absorption Using Helicity Switching By Twin Helical Undulators“. In SYNCHROTRON RADIATION INSTRUMENTATION: Eighth International Conference on Synchrotron Radiation Instrumentation. AIP, 2004. http://dx.doi.org/10.1063/1.1757978.

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Muro, T., T. Nakamura, T. Matsushita, T. Wakita, K. Fukumoto, H. Kimura, T. Hirono et al. „Status of the Twin Helical Undulator Soft X-ray Beamline at SPring-8: Performance for Circular Dichroism Measurements“. In SYNCHROTRON RADIATION INSTRUMENTATION: Ninth International Conference on Synchrotron Radiation Instrumentation. AIP, 2007. http://dx.doi.org/10.1063/1.2436125.

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Kuball, Hans-Georg, Ralph Kolling, Holger Bruening und Bernhard Weiss. „Helical twisting power and circular dichroism as chirality observations: the intramolecular and intermolecular chirality transfer in a liquid crystal phase“. In Liquid Crystals, herausgegeben von Jolanta Rutkowska, Stanislaw J. Klosowicz, Jerzy Zielinski und Jozef Zmija. SPIE, 1998. http://dx.doi.org/10.1117/12.299976.

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Xiong, Kan, Eliana K. Asciutto, Jeffry D. Madura, Sanford A. Asher, P. M. Champion und L. D. Ziegler. „Circular Dichroism and UV Resonance Raman Study of the Impact of Salts and Alcohols on the Gibbs Free Energy Landscape of an α-helical Peptide“. In XXII INTERNATIONAL CONFERENCE ON RAMAN SPECTROSCOPY. AIP, 2010. http://dx.doi.org/10.1063/1.3482854.

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Benedetti, A., R. Li Voti, A. Belardini, M. Esposito, C. Sibilia, V. Tasco, A. Passaseo und G. Leahu. „Photoacoustic detection of circular dichroism in a square array of nano-helices“. In 2015 Fotonica AEIT Italian Conference on Photonics Technologies. Institution of Engineering and Technology, 2015. http://dx.doi.org/10.1049/cp.2015.0135.

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Nakano, Sota, Takeshi Fujisawa, Takanori Sato und Kunimasa Saitoh. „Beam propagation analysis of optical activity and circular dichroism in helically twisted photonic crystal fiber“. In 2017 22nd Microoptics Conference (MOC). IEEE, 2017. http://dx.doi.org/10.23919/moc.2017.8244541.

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