Category: 65-71-4

On June 30, 2022, Cardoso, Danon Clemes; Moura, Mariana Neves; Cristiano, Maykon Passos published an article.Related Products of 65-71-4 The title of the article was Dynamic development of AT -rich heterochromatin has followed diversification and genome expansion of psammophilous Mycetophylax (Formicidae: Attini: Attina). And the article contained the following:

Heterochromatin is an important genome constituent comprised by a high d. of repetitive DNA sequences that mediate chromosome structure and function. The species Mycetophylax morschi currently harbours three cytotypes: 2n = 26, 2n = 28 and 2n = 30 chromosomes. However, Mycetophylax conformis and Mycetophylax simplex harbor 2n = 30 and 2n = 36 chromosomes, resp. None of the cytotypes of M. morschi showed any AT-pos. blocks, whereas the karyotypes of M. conformis and M. simplex revealed AT-rich blocks around the pericentromeric region and on the short arm of several chromosomes. This AT-rich pattern is coincident with the known heterochromatin distribution of psammophilous Mycetophylax, confirming that heterochromatin is AT-rich, in line with the genome size and AT%. Our results demonstrated that genome size among psammophilous Mycetophylax is correlated with the proportion of base pairs, biased to adenine and thymine. Thus, genome size and the proportion of adenine and thymine in the species studied here suggest that the genome changes in psammophilous Mycetophylax are related to the expansion of repetitive DNA in AT-rich heterochromatin. Considering the phylogenetic relationship of psammophilous Mycetophylax, the dynamic development of AT-rich heterochromatin and karyotype repatterning encompasses the diversification of such ants. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Related Products of 65-71-4

The Article related to heterochromatin genome psammophilous mycetophylax formicidae attini attina, base pairs, chromosome, genome evolution, genome size, heterochromatin, Placeholder for records without volume info and other aspects.Related Products of 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Lu, Chen; Gutierrez-Bayona, Natalia Eugenia; Taylor, John-Stephen published an article in 2021, the title of the article was The effect of flanking bases on direct and triplet sensitized cyclobutane pyrimidine dimer formation in DNA depends on the dipyrimidine, wavelength and the photosensitizer.Application of 65-71-4 And the article contains the following content:

Cyclobutane pyrimidine dimers (CPDs) are the major products of DNA produced by direct absorption of UV light, and result in C to T mutations linked to human skin cancers. Most recently a new pathway to CPDs in melanocytes has been discovered that has been proposed to arise from a chemisensitized pathway involving a triplet sensitizer that increases mutagenesis by increasing the percentage of C-containing CPDs. To investigate how triplet sensitization may differ from direct UV irradiation, CPD formation was quantified in a 129-mer DNA designed to contain all 64 possible NYYN sequences. CPD formation with UVB light varied about 2-fold between dipyrimidines and 12-fold with flanking sequence and was most frequent at YYYR and least frequent for GYYN sites in accord with a charge transfer quenching mechanism. In contrast, photosensitized CPD formation greatly favored TT over C-containing sites, more so for norfloxacin (NFX) than acetone, in accord with their differing triplet energies. While the sequence dependence for photosensitized TT CPD formation was similar to UVB light, there were significant differences, especially between NFX and acetone that could be largely explained by the ability of NFX to intercalate into DNA. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Application of 65-71-4

The Article related to cyclobutane pyrimidine dimer photosensitizer wavelength photosensitization, Placeholder for records without volume info and other aspects.Application of 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On May 13, 2021, Park, Woojin; Lee, Seunghoon; Huix-rotllant, Miquel; Filatov, Michael; Choi, Cheol ho published an article.Category: pyrimidines The title of the article was Impact of the Dynamic Electron Correlation on the Unusually Long Excited-State Lifetime of Thymine. And the article contained the following:

Non-radiative relaxation of the photoexcited thymine in the gas phase shows an unusually long excited-state lifetime, and, over the years, a number of models, i.e., S1-trapping, S2-trapping, and S1&S2-trapping, have been put forward to explain its mechanism. Here, we investigate this mechanism using non-adiabatic mol. dynamics (NAMD) simulations in connection with the recently developed mixed-reference spin-flip time-dependent d. functional theory (MRSF-TDDFT) method. We show that the previously predicted S2-trapping model was due to an artifact caused by an insufficient account of the dynamic electron correlation. The current work supports the S1-trapping mechanism with two lifetimes, τ1 = 30 ± 1 fs and τ2 = 6.1 ± 0.035 ps, quant. consistent with the recent time-resolved experiments Upon excitation to the S2 (ππ*) state, thymine undergoes an ultrafast (ca. 30 fs) S2→S1 internal conversion and resides around the min. on the S1 (nOπ*) surface, slowly decaying to the ground state (ca. 6.1 ps). While the S2→S1 internal conversion is mediated by fast bond length alternation distortion, the subsequent S1→S0 occurs through several conical intersections, involving a slow puckering motion. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Category: pyrimidines

The Article related to impact dynamic electron correlation long excited state lifetime thymine, General Physical Chemistry: General Theories and other aspects.Category: pyrimidines

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On October 14, 2021, Pomogaev, Vladimir; Lee, Seunghoon; Shaik, Sason; Filatov, Michael; Choi, Cheol Ho published an article.Electric Literature of 65-71-4 The title of the article was Exploring Dyson’s Orbitals and Their Electron Binding Energies for Conceptualizing Excited States from Response Methodology. And the article contained the following:

The MO concept is a useful tool, which relates the mol. ground-state energy with the energies (and occupations) of the individual orbitals. However, anal. of the excited states from linear response computations is performed in terms of the initial state MOs or some other forms of orbitals, e.g., natural or natural transition orbitals. Because these orbitals lack the resp. energies, they do not allow developing a consistent orbital picture of the excited states. Herein, we argue that Dyson’s orbitals enable description of the response states compatible with the concepts of MO theory. The Dyson orbitals and their energies obtained by mixed-reference spin-flip time-dependent d. functional theory (MRSF-TDDFT) for the response ground state are remarkably similar to the canonical MOs obtained by the usual DFT calculation For excited states, the Dyson orbitals provide a chem. sensible picture of the electronic transitions, thus bridging the chasm between orbital theory and response computations. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Electric Literature of 65-71-4

The Article related to dyson orbital electron binding energy excited state response methodol, General Physical Chemistry: General Theories and other aspects.Electric Literature of 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On August 7, 2021, Weng, Guorong; Vlcek, VojtEch published an article.Recommanded Product: 65-71-4 The title of the article was Efficient treatment of molecular excitations in the liquid phase environment via stochastic many-body theory. And the article contained the following:

Accurate predictions of charge excitation energies of mols. in the disordered condensed phase are central to the chem. reactivity, stability, and optoelectronic properties of mols. and critically depend on the specific environment. Herein, we develop a stochastic GW method for calculating these charge excitation energies. The approach employs maximally localized electronic states to define the electronic subspace of a mol. and the rest of the system, both of which are randomly sampled. We test the method on three solute-solvent systems: phenol, thymine, and phenylalanine in water. The results are in excellent agreement with the previous high-level calculations and available exptl. data. The stochastic calculations for supercells containing up to 1000 electrons representing the solvated systems are inexpensive and require ≤1000 central processing unit hrs. We find that the coupling with the environment accounts for ∼ 40% of the total correlation energy. The solvent-to-solute feedback mechanism incorporated in the mol. correlation term causes up to 0.6 eV destabilization of the quasiparticle energy. Simulated photoemission spectra exhibit red shifts, state-degeneracy lifting, and lifetime shortening. Our method provides an efficient approach for an accurate study of excitations of large mols. in realistic condensed phase environments. (c) 2021 American Institute of Physics. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Recommanded Product: 65-71-4

The Article related to excitation mol liquid medium stochastic many body gw method, phenol thymine phenylalanine water solvent excitation stochastic gw method, General Physical Chemistry: General Theories and other aspects.Recommanded Product: 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On May 5, 2020, Herl, Thomas; Matysik, Frank-Michael published an article.Electric Literature of 65-71-4 The title of the article was Investigation of the Electrooxidation of Thymine on Screen-Printed Carbon Electrodes by Hyphenation of Electrochemistry and Mass Spectrometry. And the article contained the following:

The electrooxidation of thymine on screen-printed C electrodes was studied using different complementary instrumental approaches. The potential-dependent product profile was obtained by recording real-time mass voltammograms. Electrochem. flow cells with integrated disposable electrodes were directly coupled with mass spectrometry to facilitate a very fast detection of electrogenerated species. Thymine dimers were found at a potential of ∼1.1 V in ammonium acetate (pH 7.0) and 1.25 V in ammonium H carbonate electrolyte (pH 8.0). Electrochem.-capillary electrophoresis-mass spectrometry measurements revealed that two isobaric isomers of a dimeric oxidation product were formed. Separations at different time intervals between end of oxidation and start of separation showed that these were hydrated over time. A study of the pKa values by changing the separation conditions in electrochem.-capillary electrophoresis-UV-visible spectroscopy measurements allowed for further characterization of the primary oxidation products. Both isomers exhibited two deprotonation steps. The oxidation products were further characterized by HPLC-tandem mass spectrometry. Based on the obtained data, the main oxidation products of thymine in aqueous solution could most likely be identified as N(1)-C(5′) and N(1)-C(6′) linked dimer species evolving into the corresponding dimer hydrates over time. The presented methods for online characterization of electrochem. pretreated samples showed that not only mass spectrometric data can be obtained by electrochem.-mass spectrometry but also further characterizations such as the study of product stability and the pH-dependent protonation or deprotonation behavior are possible. This is valid not only for stable oxidation products but also for intermediates, as anal. can be carried out within a short time scale. Thus, a vast amount of valuable exptl. data can be acquired, which can help in understanding electrooxidation processes. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Electric Literature of 65-71-4

The Article related to electrooxidation thymine screen printed carbon electrode electrochem mass spectrometry, Electrochemistry: Electrochemical Cells and Systems and other aspects.Electric Literature of 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

Green, James A.; Jouybari, Martha Yaghoubi; Aranda, Daniel; Improta, Roberto; Santoro, Fabrizio published an article in 2021, the title of the article was Nonadiabatic absorption spectra and ultrafast dynamics of DNA and RNA photoexcited nucleobases.Electric Literature of 65-71-4 And the article contains the following content:

We have recently proposed a protocol for Quantum Dynamics (QD) calculations, which is based on a parameterisation of Linear Vibronic Coupling (LVC) Hamiltonians with Time Dependent (TD) D. Functional Theory (TD-DFT), and exploits the latest developments in multiconfigurational TD-Hartree methods for an effective wave packet propagation. In this contribution we explore the potentialities of this approach to compute nonadiabatic vibronic spectra and ultrafast dynamics, by applying it to the five nucleobases present in DNA and RNA. For all of them we computed the absorption spectra and the dynamics of ultrafast internal conversion (100 fs timescale), fully coupling the first 2-3 bright states and all the close by dark states, for a total of 6-9 states, and including all the normal coordinates. We adopted two different functionals, CAM-B3LYP and PBE0, and tested the effect of the basis set. Computed spectra are in good agreement with the available exptl. data, remarkably improving over pure electronic computations, but also with respect to vibronic spectra obtained neglecting inter-state couplings. Our QD simulations indicate an effective population transfer from the lowest energy bright excited states to the close-lying dark excited states for uracil, thymine and adenine. Dynamics from higher-energy states show an ultrafast depopulation toward the more stable ones. The proposed protocol is sufficiently general and automatic to promise to become useful for widespread applications. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Electric Literature of 65-71-4

The Article related to dna rna photoexcitation nucleobase absorption spectra, nonadiabatic interactions, nucleobases, photoinduced processes, quantum dynamics, vibronic spectra, Biochemical Methods: Spectral and Related Methods and other aspects.Electric Literature of 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On July 10, 2020, Qin, Chao; Hu, Xiaojie; Waigi, Michael Gatheru; Yang, Bing; Gao, Yanzheng published an article.HPLC of Formula: 65-71-4 The title of the article was Amino and hydroxy substitution influences pyrene-DNA binding. And the article contained the following:

Polycyclic aromatic hydrocarbon (PAH)-DNA binding is an essential step in PAH-induced carcinogenesis. A large number of PAHs contain substituents, it is unclear whether functional groups will influence the PAH-DNA binding. Here, we investigated amino (-NH2) and hydroxy (-OH) substitution on pyrene-DNA binding. Because of the considerable effects of electrostatic surface potential (ESP), -NH2 substitution significantly facilitated binding by increasing the binding constant (log KA) from 4.14 L mol-1 to 12.31 L mol-1, while -OH substitution inhibited binding by reducing log KA to 3.68 L mol-1. Spectroscopy results revealed that pyrene and its derivatives were able to bind with thymine to induce DNA damage or double helix distortion. Quantum chem. calculations showed that -NH2 substitution induces hydrogen bond formation, thereby enhancing the binding of pyrene with DNA; moreover, binding force changes due to -OH substitution may not be an essential factor. All structural descriptors were not correlated with the quenching constant (KSV) or binding constant, indicating that changes in physicochem. properties shows no influence on pyrene-DNA binding. The results of this study will improve our understanding of the contribution of functional groups to PAH-DNA binding. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).HPLC of Formula: 65-71-4

The Article related to pyrene dna damage amino hydroxy group substitution, carcinogenesis, dna, functional groups, pahs, Toxicology: Carcinogens, Mutagens, and Teratogens and other aspects.HPLC of Formula: 65-71-4

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Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On March 3, 2020, Zhang, Yi; Xiao, Jing-Yu; Zhu, Yuan; Tian, Li-Jiao; Wang, Wei-Kang; Zhu, Ting-Ting; Li, Wen-Wei; Yu, Han-Qing published an article.Application of 65-71-4 The title of the article was Fluorescence Sensor Based on Biosynthetic CdSe/CdS Quantum Dots and Liposome Carrier Signal Amplification for Mercury Detection. And the article contained the following:

Mercury (Hg), as a highly harmful environmental pollutant, poses severe ecol. and health risks even at low concentrations Accurate and sensitive methods for detecting Hg2+ ions in aquatic environments are highly needed. In this work, the authors developed a highly sensitive fluorescence sensor for Hg2+ detection with an integrated use of biosynthetic CdSe/CdS quantum dots (QDs) and liposome carrier signal amplification. To construct such a sensor, three single-stranded DNA probes were rationally designed based on the thymine-Hg2+-thymine (T-Hg2+-T) coordination chem. principles and by taking advantage of the biocompatibility and facile-modification properties of the biosynthetic QDs. Hg2+ could be determined in a range from 0.25 to 100 nM with a detection limit of 0.01 nM, which met the requirements of environmental sample detection. The sensor also exhibited a high selectivity for Hg2+ detection in the presence of other high-level metal ions. A satisfactory capacity of the sensor for detecting environmental samples including tap water, river water, and landfill leachate was also demonstrated. This work opens up a new application scenario for biosynthetic QDs and holds a great potential for environmental monitoring applications. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Application of 65-71-4

The Article related to fluorescence sensor cadmium selenide sulfide quantum dot liposome mercury, Biochemical Methods: Spectral and Related Methods and other aspects.Application of 65-71-4

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia

On December 31, 2020, Dementjev, Andrej; Rutkauskas, Danielis; Polovy, Ivan; Macernis, Mindaugas; Abramavicius, Darius; Valkunas, Leonas; Dovbeshko, Galina published an article.Application of 65-71-4 The title of the article was Characterization of thymine microcrystals by CARS and SHG microscopy. And the article contained the following:

Identification of chem. homologous microcrystals in a polycrystal sample is a big challenge and requires developing specific highly sensitive tools. Second harmonic (SHG) and coherent anti-Stokes Raman scattering (CARS) spectroscopy can be used to reveal arrangement of thymine mols., one of the DNA bases, in microcrystalline sample. Strong dependence of CARS and SHG intensity on the orientation of the linear polarization of the excitation light allows to obtain high resolution images of thymine microcrystals by addnl. utilizing the scanning microscopy technique. Exptl. findings and theor. interpretation of the results are compared. Presented exptl. data together with quantum chem.-based theor. interpretation allowed us to determine the most probable organization of the thymine mols. The experimental process involved the reaction of 5-Methylpyrimidine-2,4(1H,3H)-dione(cas: 65-71-4).Application of 65-71-4

The Article related to thymine microcrystal structure cars second harmonic generation microscopy, Biochemical Methods: Spectral and Related Methods and other aspects.Application of 65-71-4

Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia