scholarly journals Electron Holes in G-Quadruplexes: The Role of Adenine Ending Groups

2021 ◽  
Vol 22 (24) ◽  
pp. 13436
Author(s):  
Evangelos Balanikas ◽  
Lara Martinez-Fernandez ◽  
Gérard Baldacchino ◽  
Dimitra Markovitsi
Keyword(s):  
Radical Cations ◽  
Fast Process ◽  
Electron Hole ◽  
Time Resolved ◽  
Dna Structures ◽  
Quantum Chemistry Calculations ◽  
Uv Photons ◽  
Electron Holes ◽  
The One

The study deals with four-stranded DNA structures (G-Quadruplexes), known to undergo ionization upon direct absorption of low-energy UV photons. Combining quantum chemistry calculations and time-resolved absorption spectroscopy with 266 nm excitation, it focuses on the electron holes generated in tetramolecular systems with adenine groups at the ends. Our computations show that the electron hole is placed in a single guanine site, whose location depends on the position of the adenines at the 3′ or 5′ ends. This position also affects significantly the electronic absorption spectrum of (G+)● radical cations. Their decay is highly anisotropic, composed of a fast process (<2 µs), followed by a slower one occurring in ~20 µs. On the one hand, they undergo deprotonation to (G-H2)● radicals and, on the other, they give rise to a reaction product absorbing in the 300–500 nm spectral domain.

Vibrational Studies on the Dynamics of Switching between the Surface-Stabilized States of a Ferroelectric Liquid Crystal by Asynchronous Time-Resolved Fourier Transform Infrared Spectroscopy

1993 ◽  
Vol 47 (9) ◽  
pp. 1370-1375 ◽  
Author(s):  
Koji Masutani ◽  
Akira Yokota ◽  
Yukio Furukawa ◽  
Mitsuo Tasumi ◽  
Atsushi Yoshizawa
Keyword(s):  
Liquid Crystal ◽  
Time Behavior ◽  
Ferroelectric Liquid Crystal ◽  
Slow Process ◽  
Fast Process ◽  
Time Resolved ◽  
Smectic C ◽  
Rigid Molecule ◽  
Vibrational Studies

Time-resolved polarized infrared spectra have been observed from a ferroelectric liquid crystal (chiral smectic C phase) consisting of a chiral dopant and a nonchiral smectic base during the course of switching between the surface-stabilized states. A primary fast process and the subsequent slow process have been observed for all infrared bands. The chiral dopant and smectic base molecules move simultaneously. The observed time behavior of the infrared bands can be mostly explained by the reorientation of a rigid molecule whose rotational motion around the molecular long axis is almost free. The static intensities and the time behavior of the ester and keto C=O stretching bands do not seem to be consistent with the simple view on the role of these groups.

scholarly journals Guanine Radicals Generated in Telomeric G-Quadruplexes by Direct Absorption of Low-Energy UV Photons: Effect of Potassium Ions

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2094 ◽  
Author(s):  
Evangelos Balanikas ◽  
Akos Banyasz ◽  
Gérard Baldacchino ◽  
Dimitra Markovitsi
Keyword(s):  
Transient Absorption ◽  
Radical Cations ◽  
Low Energy ◽  
Transient Absorption Spectroscopy ◽  
Potassium Ions ◽  
Direct Absorption ◽  
Dna Structures ◽  
Photon Ionization ◽  
Uv Photons ◽  
Photo Ionization

The study deals with the primary species, ejected electrons, and guanine radicals, leading to oxidative damage, that is generated in four-stranded DNA structures (guanine quadruplexes) following photo-ionization by low-energy UV radiation. Performed by nanosecond transient absorption spectroscopy with 266 nm excitation, it focusses on quadruplexes formed by folding of GGG(TTAGGG)3 single strands in the presence of K+ ions, TEL21/K+. The quantum yield for one-photon ionization (9.4 × 10−3) was found to be twice as high as that reported previously for TEL21/Na+. The overall population of guanine radicals decayed faster, their half times being, respectively, 1.4 and 6.7 ms. Deprotonation of radical cations extended over four orders of magnitude of time; the faster step, concerning 40% of their population, was completed within 500 ns. A reaction intermediate, issued from radicals, whose absorption spectrum peaked around 390 nm, was detected.

scholarly journals The Two Faces of the Guanyl Radical: Molecular Context and Behavior

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3511
Author(s):  
Chryssostomos Chatgilialoglu
Keyword(s):  
Theoretical Calculations ◽  
Complex Mechanism ◽  
Time Resolved ◽  
Tautomeric Forms ◽  
G Quadruplex ◽  
Molecular Context ◽  
The One ◽  
And Behavior ◽  
Intense Research

The guanyl radical or neutral guanine radical G(-H)• results from the loss of a hydrogen atom (H•) or an electron/proton (e–/H+) couple from the guanine structures (G). The guanyl radical exists in two tautomeric forms. As the modes of formation of the two tautomers, their relationship and reactivity at the nucleoside level are subjects of intense research and are discussed in a holistic manner, including time-resolved spectroscopies, product studies, and relevant theoretical calculations. Particular attention is given to the one-electron oxidation of the GC pair and the complex mechanism of the deprotonation vs. hydration step of GC•+ pair. The role of the two G(-H)• tautomers in single- and double-stranded oligonucleotides and the G-quadruplex, the supramolecular arrangement that attracts interest for its biological consequences, are considered. The importance of biomarkers of guanine DNA damage is also addressed.

The key role of geminate electron–hole pair recombination in the delayed fluorescence in rhodamine 6G and ATTO-532

2014 ◽  
Vol 16 (39) ◽  
pp. 21543-21549 ◽  
Author(s):  
Murat Aydemir ◽  
Vygintas Jankus ◽  
Fernando B. Dias ◽  
Andy Monkman
Keyword(s):  
Excitation Energy ◽  
Rhodamine 6G ◽  
Delayed Fluorescence ◽  
Hole Pair ◽  
Laser Dye ◽  
Electron Hole ◽  
Time Resolved ◽  
Highly Sensitive ◽  
Electron Hole Pair

In this paper we investigate the delayed fluorescence (DF) phenomena in the widely used laser dye, rhodamine 6G, and its derivative ATTO-532 as a function of excitation energy using highly sensitive time-resolved gated nanosecond spectroscopy.

You Are the One I Want to Communicate With!

2013 ◽  
Vol 44 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Sabrina Pierucci ◽  
Olivier Klein ◽  
Andrea Carnaghi
Keyword(s):  
Memory Bias ◽  
Shared Reality ◽  
Communication Partner ◽  
Shared Reality Theory ◽  
The One ◽  
Study Participants

This article investigates the role of relational motives in the saying-is-believing effect ( Higgins & Rholes, 1978 ). Building on shared reality theory, we expected this effect to be most likely when communicators were motivated to “get along” with the audience. In the current study, participants were asked to describe an ambiguous target to an audience who either liked or disliked the target. The audience had been previously evaluated as a desirable vs. undesirable communication partner. Only participants who communicated with a desirable audience tuned their messages to suit their audience’s attitude toward the target. In line with predictions, they also displayed an audience-congruent memory bias in later recall.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1961 ◽  
Vol 6 (02) ◽  
pp. 224-234 ◽  
Author(s):  
E. T Yin ◽  
F Duckert
Keyword(s):  
Intermediate Product ◽  
Factor Ix ◽  
Assay Method ◽  
Lag Phase ◽  
Factor X ◽  
Haemophilia B ◽  
Hageman Factor ◽  
One Stage ◽  
The One

Summary1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

THE ROLE OF ANTHROPONYMS IN THE SEMANTIC FIELD OF ARTISTIC WORKS

2019 ◽  
Vol 2019 (29) ◽  
pp. 66-77
Author(s):  
Lidiya Derbenyova
Keyword(s):  
Literary Work ◽  
Main Theme ◽  
Semantic Field ◽  
New Meanings ◽  
Minor Part ◽  
The One ◽  
A Minor ◽  
And Storage ◽  
Horizon Of Expectations

The article explores the role of antropoetonyms in the reader’s “horizon of expectation” formation. As a kind of “text in the text”, antropoetonyms are concentrating a large amount of information on a minor part of the text, reflecting the main theme of the work. As a “text” this class of poetonyms performs a number of functions: transmission and storage of information, generation of new meanings, the function of “cultural memory”, which explains the readers’ “horizon of expectations”. In analyzing the context of the literary work we should consider the function of antropoetonyms in vertical context (the link between artistic and other texts, and the groundwork system of culture), as well as in the context of the horizontal one (times’ connection realized in the communication chain from the word to the text; the author’s intention). In this aspect, the role of antropoetonyms in the structure of the literary text is extremely significant because antropoetonyms convey an associative nature, generating a complex mechanism of allusions. It’s an open fact that they always transmit information about the preceding text and suggest a double decoding. On the one hand, the recipient decodes this information, on the other – accepts this as a sort of hidden, “secret” sense.

Public Procurement Principles Generated by the Treaty of Rome

2020 ◽  
Vol 26 (2) ◽  
pp. 217-223
Author(s):  
Ioan-Gabriel Popa
Keyword(s):  
European Economic Community ◽  
Public Procurement ◽  
Free Movement ◽  
European Directives ◽  
Community Institutions ◽  
Treaty Of Rome ◽  
General Principles Of Law ◽  
Free Movement Of Goods ◽  
The One

AbstractIn order to understand the principles of public procurement in Romania, it is necessary to analyze, on the one hand, the European directives that regulate the actual public procurement and, on the other hand, the context in which the European directives were adopted. Even with the directives in force, the more general provisions contained in the Treaty of the European Economic Community (EEC) in Rome, hereinafter referred to as the Treaty, are applied, as well as many more general principles of law that will guide the interpretation of these directives. The Treaty was adopted in Rome, in 1957 and became applicable from January 1, 1958. It is considered that the source of the principles of public procurement is the Treaty. Even if in Treaty contained no specific provisions regarding the field of public procurement, it reflects the principles and the general framework for the functioning of the single market, a market characterized through the prism of the fundamental freedoms established by the Treaty: the free movement of goods, services, capital and persons. As the field of public procurement is closely linked to the free movement of goods, this principle is promoted and implemented in the practice of this field based on the regulations, directives and decisions of the Community institutions. The role of the free movement of goods is to harmonize the relationships involved in the process of purchasing goods, but also to ensure the homogeneity, coherence and balance of this process.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

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