Insight into Mechanism of Formation of C8 Adducts in Carcinogenic Reactions of Arylnitrenium Ions with Purine Nucleosides

2009 ◽  
Vol 113 (1) ◽  
pp. 254-259 ◽  
Author(s):  
Zhong-Zhi Yang ◽  
Shi-Fei Qi ◽  
Dong-Xia Zhao ◽  
Li-Dong Gong
Keyword(s):  
Mechanism Of Formation ◽  
Arylnitrenium Ions ◽  
Insight Into

INSIGHT INTO MECHANISM OF FORMATION OF C8 ADDUCTS IN CARCINOGENIC REACTIONS OF ARYLNITRENIUM IONS WITH PURINE NUCLEOSIDES II: AB INITIO, DFT, AND ABEEM/MM-MD SIMULATION STUDIES OF CHEMICAL REACTIONS CONCERNING N9-SUBSTITUTED PURINE BASES WITH 4-BIPHENYLYLNITRENIUM ION

2009 ◽  
Vol 08 (supp01) ◽  
pp. 1053-1071 ◽  
Author(s):  
SHI-FEI QI ◽  
XIAO-NAN WANG ◽  
ZHONG-ZHI YANG
Keyword(s):  
Theoretical Model ◽  
Ab Initio ◽  
Density Functional ◽  
Mechanism Of Formation ◽  
Dft Methods ◽  
Functional Theory ◽  
Direct Formation ◽  
Arylnitrenium Ions ◽  
Theoretical Insight ◽  
Insight Into

Theoretical insight into the mechanism of C8 adducts formation in a series of complicated carcinogenic reactions has been provided in a previous work. However, two important issues involved in this mechanism still need to be elucidated in detail. Hence, in this paper, we first present a new theoretical model to study the direct formation mechanism of C8 adduct. It is found that this model can well reflect the actual interactions in the real carcinogenic reactions. Thus, a better theoretical model to simulate other properties of these complicated reactions is found using ab initio and density functional theory (DFT) methods. Second, we simulate the formation process of C8 adduct in this new theoretical model using ABEEM/MM-MD method. According to the MD study, we approve that the higher aqueous-phase activation energy for transition state in this kind of reaction contributes to weaker interactions between central sites of reaction and water compared with those for reactants. This study once more supports the mechanism of formation of C8 adducts in the actual carcinogenic reactions where arylnitrenium ions directly attack at C8 positions of nucleoside bases in DNA.

Intraneural ganglia in the hip and pelvic region

2009 ◽  
Vol 111 (2) ◽  
pp. 317-325 ◽  
Author(s):  
Robert J. Spinner ◽  
Marie-Noëlle Hébert-Blouin ◽  
Robert T. Trousdale ◽  
Rajiv Midha ◽  
Stephen M. Russell ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Mr Imaging ◽  
Hip Joint ◽  
Lumbosacral Plexus ◽  
Mr Images ◽  
Mechanism Of Formation ◽  
Intraneural Ganglion ◽  
Rare Site ◽  
Joint Connection ◽  
Insight Into

Object The authors describe their experience in a series of cases of intraneural ganglia within the hip and pelvic regions, and explain the mechanism of formation and propagation of this pathological entity. Methods Five patients with 6 intraneural ganglia are presented. Four patients presented with symptomatic intraneural ganglia in the buttock and pelvis affecting the sciatic and lumbosacral plexus elements. An asymptomatic cyst affecting the opposite sciatic nerve was found on MR imaging in 1 patient. The fifth patient, previously reported on by another group, had an obturator intraneural ganglion that the authors reinterpreted. Results All 5 intraneural ganglia affecting the sciatic and lumbosacral plexus elements were found to have a joint connection to the posteromedial aspect of the hip joint; the obturator intraneural cyst had a joint connection to the anteromedial aspect of the hip joint. In all cases, initial review of the MR images led to their misinterpretation. Conclusions To the authors' knowledge, these are the first cases of intraneural ganglia demonstrated to have a connection to the hip joint. This finding at a rare site provides further evidence for the unifying articular (synovial) theory for the formation of intraneural ganglia and reveals a shared mechanism for their propagation. Furthermore, understanding the pathogenesis of these lesions provides insight into their successful treatment and their recurrence.

scholarly journals Synthesis and Conformational Analysis of Fluorinated Uridine Analogues Provide Insight into a Neighbouring-Group Participation Mechanism

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5513
Author(s):  
Freideriki Michailidou ◽  
Tomas Lebl ◽  
Alexandra M. Z. Slawin ◽  
Sunil Vishnuprasadji Sharma ◽  
Murray J. B. Brown ◽  
...  
Keyword(s):  
Conformational Analysis ◽  
Antiviral Agents ◽  
Synthetic Methods ◽  
Nucleoside Analogues ◽  
Mechanism Of Formation ◽  
Group Participation ◽  
Enzymatic Function ◽  
Neighbouring Group Participation ◽  
Sn2 Pathway ◽  
Insight Into

Fluorinated nucleoside analogues have attracted much attention as anticancer and antiviral agents and as probes for enzymatic function. However, the lack of direct synthetic methods, especially for 2′,3′-dideoxy-2′,3′-difluoro nucleosides, hamper their practical utility. In order to design more efficient synthetic methods, a better understanding of the conformation and mechanism of formation of these molecules is important. Herein, we report the synthesis and conformational analysis of a 2′,3′-dideoxy-2′,3′-difluoro and a 2′-deoxy-2′-fluoro uridine derivative and provide an insight into the reaction mechanism. We suggest that the transformation most likely diverges from the SN1 or SN2 pathway, but instead operates via a neighbouring-group participation mechanism.

Oxygen-18 Sulfate Isotopomers Monitored by Infrared Spectroscopy

1994 ◽  
Vol 48 (6) ◽  
pp. 691-694 ◽  
Author(s):  
Brian J. Reedy ◽  
James K. Beattie ◽  
Richard T. Lowson
Keyword(s):  
Infrared Spectroscopy ◽  
Isotopic Exchange ◽  
Vibrational Mode ◽  
Air Oxidation ◽  
Mechanism Of Formation ◽  
Isotopic Tracer ◽  
Solvent Water ◽  
Insight Into ◽  
Tracer Experiments

Infrared spectroscopy has been used with oxygen-18 isotopic tracer experiments to provide insight into the mechanism of formation of sulfate by the air oxidation of sulfite, thiosulfate, or tetrathionate ions. The relative amounts of each of the different isotope isomers, or isotopomers, can be observed qualitatively by their characteristic totally symmetric vibrational mode frequencies. The source of the 18O can be either dioxygen or the solvent water. By reversing the source of the isotope, one can check the results for isotopic exchange and/or impurities.

Further insight into the mechanism of formation of hydroxyaluminosilicates

Polyhedron ◽  
2006 ◽  
Vol 25 (17) ◽  
pp. 3399-3404 ◽  
Author(s):  
Stanislav Strekopytov ◽  
Eve Jarry ◽  
Christopher Exley
Keyword(s):  
Mechanism Of Formation ◽  
Insight Into

Insight into the Mechanism of Formation of Channel Hydrates via Templating

2014 ◽  
Vol 14 (3) ◽  
pp. 1158-1166 ◽  
Author(s):  
Stephen P. Stokes ◽  
Colin C. Seaton ◽  
Kevin S. Eccles ◽  
Anita R. Maguire ◽  
Simon E. Lawrence
Keyword(s):  
Mechanism Of Formation ◽  
Insight Into

scholarly journals “In-System” Fission-Events: An Insight into Puzzles of Exoplanets and Stars?

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 118
Author(s):  
Elizabeth P. Tito ◽  
Vadim I. Pavlov
Keyword(s):  
Stellar Systems ◽  
Mechanism Of Formation ◽  
Recent Proposal ◽  
Stellar Objects ◽  
Second Stage ◽  
Exoplanetary Systems ◽  
Orbital Periods ◽  
Two Stages ◽  
Insight Into

In expansion of our recent proposal that the solar system’s evolution occurred in two stages—during the first stage, the gaseous giants formed (via disk instability), and, during the second stage (caused by an encounter with a particular stellar-object leading to “in-system” fission-driven nucleogenesis), the terrestrial planets formed (via accretion)—we emphasize here that the mechanism of formation of such stellar-objects is generally universal and therefore encounters of such objects with stellar-systems may have occurred elsewhere across galaxies. If so, their aftereffects may perhaps be observed as puzzling features in the spectra of individual stars (such as idiosyncratic chemical enrichments) and/or in the structures of exoplanetary systems (such as unusually high planet densities or short orbital periods). This paper reviews and reinterprets astronomical data within the “fission-events framework”. Classification of stellar systems as “pristine” or “impacted” is offered.

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