Analysis of the Relative Stability ofcis-Urocanic Acid in Condensed Phase. The Use of Langevin Dipoles

2002 ◽  
Vol 106 (28) ◽  
pp. 7115-7120 ◽  
Author(s):  
Jose Manuel Hermida-Ramón ◽  
Gunnar Karlström ◽  
Roland Lindh
Author(s):  
Valery P. Sinditskii ◽  
Viacheslav Yu. Egorshev ◽  
Valery V. Serushkin ◽  
Anton I. Levshenkov ◽  
Maxim V. Berezin ◽  
...  

1993 ◽  
Vol 58 (5) ◽  
pp. 1103-1108 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Eman M. Shoukry

The formation constants of the binary and ternary complexes of palladium(II) with diethylenetriamine and amino acids as ligands have been determined potentiometrically at 25 °C in 0.1 M NaNO3 solution. The relative stability of each ternary complex was compared with that of the corresponding binary complexes in terms of ∆logK values. The mode of chelation was ascertained by conductivity measurements.


2021 ◽  
Vol 22 (15) ◽  
pp. 7879
Author(s):  
Yingxia Gao ◽  
Yi Zheng ◽  
Léon Sanche

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.


2021 ◽  
Vol 13 (8) ◽  
pp. 4229
Author(s):  
Fakher Abbas ◽  
Fang Lin ◽  
Zhaolong Zhu ◽  
Shaoshan An

As soil stability is a complex phenomenon, various methods and indexes were introduced to assess the strength of soils. Because of the limitations of different stability methods and indexes (including wet sieving-based), we aimed to presents a relative stability index (RI) that was based on the estimated components of the soil overall disruptive characteristic curve (SODC): (1) soil disruption constant (Ki, that is based upon dispersion energy of soils); (2) resulting change in mean weight diameter (ΔMWD). To evaluate the effectiveness and limitations of RI as well as to compare it with classical soil stability indexes of mean weight diameter (MWD) and geometric mean diameter (GMD). Ultrasonic agitation (UA) along with a wet sieving method (followed by dry sieving) was applied against four different soils named on the basis of sample location, Qingling soil (QL), Guanzhong soil (GZ), Ansai soil (AS), and Jingbian soil (JB). To evaluate the relative strength of soils at different applied energies (increase in sonication duration usually resulted in increased input energy and temperature of soil–water suspension), soils were subjected to six sonication durations (0, 30, 60, 120, 210, and 300 s) with a fixed (and exact) initial amplitude and temperature. Output energy was calculated based on the amplitude and temperature of the suspension, vessel, and system. The most abrupt and maximum disruption of soil aggregates was observed at a dispersion energy level of 0–200 J g−1. The MWD value of surface and subsurface ranged between 0.58 to 0.15 mm and 0.37 to 0.17 mm, respectively, while GMD was ranged from 0.14 to 0.33 mm overall. The results for MWD and GMD showed a similar trend. MWD and GMD showed more strong associations with physicochemical characteristics of soil than RI. A non-significant correlation was found between RI and MWD/GMD. Contrary to MWD and GMD, RI was significantly positively correlated with sand content; this finding indicated the influential role of sand in assessing the soil’s relative strength. The results indicated that JB soil possessed the least MWD and GMD but proved to be relatively stable because of having the highest RI value.


Synthesis ◽  
2021 ◽  
Author(s):  
Michio Kurosu ◽  
Katsuhiko Mitachi ◽  
David Mingle

Abstract(4,4′-Bisfluorophenyl)methoxymethyl (BFPM) group of uridine ureido nitrogen shows good relative stability in a variety of chemical transformation reactions for uridine. The BFPM group can be cleaved by 2% of TFA in CH2Cl2 without affecting the Boc group.


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