共查询到20条相似文献,搜索用时 15 毫秒
1.
I. M. Piskarev I. P. Ivanova S. V. Trofimova A. A. Ichetkina O. E. Burkhina 《High Energy Chemistry》2014,48(5):350-352
The reaction of the stable free radical diphenylpicrylhydrazyl (DPPH·) with water treated by plasma radiation of air spark discharge immediately after irradiation and for 13 days after irradiation has been studied. The choice is due to the fact that peroxynitrous acid ONOOH, which can be generated by irradiation, is a donor of atomic hydrogen and the reaction with DPPH· allows the acid concentration to be determined. The formation of ONOOH has been detected by the 4th day after the treatment, [ONOOH] = (1.5 ± 0.5) × 10?5 mol/L. This finding confirms the earlier assumption that a complex containing peroxynitrite and peroxynitrous acid is produced in water and decomposes within 13 to 14 days. 相似文献
2.
We studied the reactivity of peroxynitrite and different nucleic acid molecules using DNA electrochemical biosensors. SIN‐1 (3‐morpholinosydnonimine) has been used for the simultaneous generation of NO?and superoxide, i.e., as a peroxynitrite (ONOO?) donor. Double strand DNA (dsDNA), single strand DNA (ssDNA) and 15 guanine bases oligonucleotide (Oligo(dG)15) were immobilized on a carbon paste electrode to generate the biosensor and DPV was selected as the electroanalytical technique. Results showed that electrochemical biosensors were very sensitive for detecting interaction between ONOO? and DNA. A down/up effect was observed, i.e., at low ONOO? concentrations the guanine oxidation signal decreased while at high ONOO? concentrations the guanine oxidation current increased. Oligo(dG)15 exhibited greater interaction at low ONOO? concentrations than the other DNA molecules. The reactivity between ONOO? and DNA was also evaluated in solution phase, showing the same down/up effect. Finally, the capacity of DNA to hybridize was prevented after interaction with ONOO?. 相似文献
3.
Given that peroxynitrite (ONOO?) is profoundly associated with health and diseases, a new fluorescent probe ABT was designed and synthesized for detection of ONOO?. ABT manifested not only ratiometric fluorescence signals simultaneously in response to concentrations of ONOO? (within 10?s), but high selectivity and sensitivity towards ONOO? over other physiological relevant species (detection limit?=?26.3?nM). Moreover, ABT worked in a broad pH range with biological relevance. Thus, ABT could be used to quantitative detection of ONOO? concentration and has the potential to efficiently monitor ONOO? in living organisms. 相似文献
4.
在体内NO和超氧阴离子生成的过氧亚硝酸根离子(ONOO-,peroxynitrite)是一种强氧化性物质,它可以诱导DNA单链断裂使DNA发生损伤。为了探讨ONOO-断裂DNA的作用机理,以质粒DNA pBR322为研究对象,采用琼脂糖凝胶和硫代巴比妥酸(TBA)显色反应等方法对ONOO-与DNA的反应进行研究。结果表明ONOO-能明显使DNA发生断裂,而且随着ONOO-浓度的增加,DNA断裂的程度增加,在酸性和中性条件下ONOO-断裂DNA的能力明显高于碱性介质,而CO2对该反应有显著的抑制作用,TBA显色反应进一步证实该反应为自由基机理,其机理为ONOO-与H+形成ONOOH,然后裂解为二氧化氮自由基(·NO2)和羟基自由基(·OH),继而对DNA造成损伤。 相似文献
5.
This work describes the conditions of use of bare gold electrode to detect electrochemically the presence of peroxynitrite ONOO? in phosphate buffer solution at pH 7.1. As ONOO? is extremely unstable in neutral solution, current–potential curve was reconstructed between ?0.5 and 0.7 V vs SCE by amperometry experiments at rotating disk electrode at different potentials. Comparison of this reconstructed curve with voltammograms of the common interfering species (dopamine, hydrogen peroxide, nitrite, ascorbic acid and glutamate) shows that the presence of ONOO? can be selectively determined at ?0.1 V vs SCE. This detection occurs through the electrochemical reduction of peroxynitrous acid ONOOH, the conjugated acid of ONOO?. Detection of ONOO? produced in situ by the reaction of nitric oxide with superoxide was also achieved. 相似文献
6.
Julia Modrzejewska Marcin Szala Aleksandra Grzelakowska Magorzata Zakos-Szyda Jacek Zielonka Radosaw Podsiady 《Molecules (Basel, Switzerland)》2021,26(19)
Derivatives of coumarin, containing oxidant-sensitive boronate group, were recently developed for fluorescent detection of inflammatory oxidants. Here, we report the synthesis and the characterization of 3-(2-benzothiazolyl)-7-coumarin boronic acid pinacol ester (BC-BE) as a fluorescent probe for the detection of peroxynitrite (ONOO–), with high stability and a fast response time. The BC-BE probe hydrolyzes in phosphate buffer to 3-(2-benzothiazolyl)-7-coumarin boronic acid (BC-BA) which is stable in the solution even after a prolonged incubation time (24 h). BC-BA is slowly oxidized by H2O2 to form the phenolic product, 3-benzothiazol-2-yl-7-hydroxy-chromen-2-one (BC-OH). On the other hand, the BC-BA probe reacts rapidly with ONOO−. The ability of the BC-BA probe to detect ONOO– was measured using both authentic ONOO– and the system co-generating steady-state fluxes of O2•– and •NO. BC-BA is oxidized by ONOO– to BC-OH. However, in this reaction 3-benzothiazol-2-yl-chromen-2-one (BC-H) is formed in the minor pathway, as a peroxynitrite-specific product. BC-OH is also formed in the reaction of BC-BA with HOCl, and subsequent reaction of BC-OH with HOCl leads to the formation of a chlorinated phenolic product, which could be used as a specific product for HOCl. We conclude that BC-BA shows potential as an improved fluorescent probe for the detection of peroxynitrite and hypochlorite in biological settings. Complementation of the fluorescence measurements by HPLC-based identification of oxidant-specific products will help to identify the oxidants detected. 相似文献
7.
Dr. Zhiqiang Shen Shaoqiu Zheng Yuanmeng Fang Prof. Dr. Guoying Zhang Prof. Dr. Chen Zhu Prof. Dr. Shiyong Liu Prof. Dr. Jinming Hu 《Angewandte Chemie (International ed. in English)》2023,62(20):e202219153
The peroxynitrite anion (ONOO−) is closely associated with many diseases and the creation of ONOO− donors is an essential means of understanding its pathophysiological functions. However, it is challenging to develop ONOO− donors due to the difficulties in simultaneously producing highly reactive and short-lived nitric oxide (NO) and superoxide anion (O2⋅−). Here, we report a novel strategy for constructing ONOO− donors by combining near-infrared (NIR)-mediated type I photosensitization and photoredox catalysis. The key design using a Nile blue analogue that can serve as both a type I photosensitizer and a metal-free photocatalyst. Intriguingly, the formation of O2⋅− via type I photosensitization avoids oxygen interference and instead activates nitrobenzofurazan-based NO donors via oxygen-tolerant NIR photoredox catalysis. The simultaneous release of O2⋅− and NO leads to ONOO− release, showing both antibacterial and antibiofilm activities. 相似文献
8.
Cuihong Song Zhiqiang Ye Dr. Guilan Wang Prof. Jingli Yuan Prof. Yafeng Guan Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(22):6464-6472
A lanthanide‐complex‐based ratiometric luminescence probe specific for peroxynitrite (ONOO?), 4′‐(2,4‐dimethoxyphenyl)‐2,2′:6′,2′′‐terpyridine‐6,6′′‐diyl]bis(methylenenitrilo)tetrakis(acetate)‐Eu3+/Tb3+ ([Eu3+/Tb3+(DTTA)]), has been designed and synthesized. Both [Eu3+(DTTA)] and [Tb3+(DTTA)] are highly water soluble with large stability constants at ≈1020, and strongly luminescent with luminescence quantum yields of 10.0 and 9.9 %, respectively, and long luminescence lifetimes of 1.38 and 0.26 ms, respectively. It was found that the luminescence of [Tb3+(DTTA)] could be quenched by ONOO? rapidly and specifically in aqueous buffers, while that of [Eu3+(DTTA)] did not respond to the addition of ONOO?. Thus, by simply mixing [Eu3+(DTTA)] and [Tb3+(DTTA)] in an aqueous buffer, a ratiometric luminescence probe specific for time‐gated luminescence detection of ONOO? was obtained. The performance of [Tb3+(DTTA)] and [Eu3+/Tb3+(DTTA)] as the probes for luminescence imaging detection of ONOO? in living cells was investigated. The results demonstrated the efficacy and advantages of the new ratiometric luminescence probe for highly sensitive luminescence bioimaging application. 相似文献
9.
A. D. Grishina T. V. Krivenko V. V. Savel’ev R. W. Rychwalski A. V. Vannikov 《High Energy Chemistry》2014,48(5):337-342
The study has focused on polyvinylcarbazole (PVK) composites with graphene. It has been shown that there is a noticeable nonadditive shoulder on the long-wavelength edge of the optical absorption of PVK in these samples, which can be attributed to the formation of a charge-transfer complex between PVK as a donor and graphene as an acceptor. The formation of the complex causes a significant nonlinear optical effect in the PVK/graphene composite. The revealed increase in both the nonlinearity coefficient with increasing laser intensity and the cross section with increasing incident energy density is due to the formation of the graphene?· radical anion, an additional species contributing to nonlinear absorption, with an increase in the radiation energy density. Nonlinear optical properties of PVK composites with graphene isolated from a solution in tetrachloroethane after 1.5-h centrifugation (sample 1) have been considered. It has been suggested that a significant decrease in optical transmission of laser radiation by the composite T OA = 0.4 at an energy density at focus of 502 J/cm2 is due to the formation of the PVK/graphene charge-transfer complex responsible for the nonadditive shoulder on the long-wavelength optical absorption edge of PVK. During photoexcitation of graphene in the PVK/graphene composites at a laser wavelength of 1064 nm, mobile holes are generated in PVK, indicating the formation of graphene?· radical anions as a result of charge transfer from PVK to photoexcited graphene. The observed increase in both β with an increase in the laser radiation intensity and the cross section (σexc — σ0) with an increase in the incident energy density may be due to either the contribution of nonlinear transitions (S 0 → S 2, S 0 → S 1 → S 2, T 1 → T 2) or the formation of the additional species, the graphene-· radical anions, participating in nonlinear absorption by increasing the energy density at the focus (F foc, J/cm2). 相似文献
10.
Chunyan Li Wanfei Li Huanhuan Liu Yejun Zhang Guangcun Chen Zijing Li Qiangbin Wang 《Angewandte Chemie (International ed. in English)》2020,59(1):247-252
Traumatic brain injury (TBI) is one of the most dangerous acute diseases resulting in high morbidity and mortality. Current methods remain limited with respect to early diagnosis and real‐time feedback on the pathological process. Herein, a targeted activatable fluorescent nanoprobe (V&A@Ag2S) in the second near‐infrared window (NIR‐II) is presented for in vivo optical imaging of TBI. Initially, the fluorescence of V&A@Ag2S is turned off owing to energy transfer from Ag2S to the A1094 chromophore. Upon intravenous injection, V&A@Ag2S quickly accumulates in the inflamed vascular endothelium of TBI based on VCAM1‐mediated endocytosis, after which the nanoprobe achieves rapid recovery of the NIR‐II fluorescence of Ag2S quantum dots (QDs) owing to the bleaching of A1094 by the prodromal biomarker of TBI, peroxynitrite (ONOO?). The nanoprobe offers high specificity, rapid response, and high sensitivity toward ONOO?, providing a convenient approach for in vivo early real‐time assessment of TBI. 相似文献
11.
We describe a rapid and convenient colorimetric method for the detection of oxidative DNA damage caused by peroxynitrite (ONOO?) using unmodified gold nanoparticles (AuNPs). AuNPs are stable in the presence of single-stranded DNA (ssDNA) against the aggregation induced by a high ionic strength. If adsorbed ssDNA are cleaved by ONOO? to form smaller fragments, the AuNPs rapidly aggregate due to electrostatic attraction. As a result, the color of the solution changes from red to blue, and this can be seen with bare eyes. We also have evaluated the activity of the antioxidants gallic acid, ascorbic acid and caffeic acid to scavenge ONOO?. This method therefore also can be applied to screen for anti-oxidation drugs and agents. Figure
ONOO?-induced ssDNA cleavage can be visually detected by a red-to-blue color change of AuNPs. 相似文献
12.
Ion production resulting from excitation of K atoms to m2P (m ? 6) levels has been observed in mixtures of K with various species. Mass spectrometric data provide direct evidence for the occurrence of K(m2P) + K(4 2S) → K2+ + e? and are consistent with the formation of unstable KX+ ions from K(m2P) + X → KX+ + e? for X = C2H4, CH4, N2. 相似文献
13.
Strongly enhanced N2 first positive emission N2(B 3Πg → A 3Σ+u) has been observed on addition of N atoms into a flowing mixture of Cl and HN3. The dependence of the emission intensity on N atom concentration gave a rate constant for the reaction N + N3 → N2(B 3Πg) + N2(X 1Σ+g) of i(1.6 ± 1.1) × 10?11 cm3 molecule?1 s?1. That for the reaction Cl + HN3 → HCl + N3 is (8.9 ± 1.0) × 10?13 cm3 molecule?1 s?1 from the decay of the emission. Comparison of the emission intensity in ClHN3 with that in ClHN3N gave the rate constant of the reaction N3 + N3 → N2(B 3Πg) + 2N2(X 1Σ+g) as 1.4 × 10?12 cm3 molecule?1 s?1 on the assumption that N + N3 yields only N2(B 3Πg) + N2(X 1Σ+g). 相似文献
14.
Emission spectra between 185 and 600 nm have been investigated following near-thermal charge exchange between He+ and N2O and ≤ 100 eV electron impact on N2O. The charge exchange produces N2O+Ã→X?and N2+ B → X emission, but the two band systems account for at most 5% of all charge transfer products. These results and literature data on Ar+/N2O are discussed in the light of Franck—Condon and energy resonance criteria as applied to low-energy charge exchange. The electron-impact experiments revealed a weak (≈ 10?3) long-lived (≈ 50 × 10?6 s) component in the N2O+Ã→X?emission. 相似文献
15.
NH(A3Π → X3Σ?) and OH(A2Σ+ → X2Π) chemiluminescences from the reaction of CH(X2Π) with NO and O2, respectively, have been observed at room temperature. From the decay of such emissions we have measured the rate constants for these two reactions: kNO = (2.5 ± 0.5) × 10?10 and kO2 = (8 ± 3) × 10?11 cm3 molecule ?1 s?1, which are in agreement with previously reported rates determined by direct CH(X) detection using, laser-induced fluorescence. This indicates that a four-centered mechanism generating these excited species is operative in both reactions. The CH generation from 266 nm photolysis of CHBr3 has also been investigated via analysis of CH* emissions. 相似文献
16.
The excitation and emission spectra and decay times of several MnX2-4 (X = Cl?, Br?, 1?) complexes of various tetraalkylammonium, -phosphonium, and -arsonium salts have been measured for the pure solids at 298°K and 77°K. High luminescence quantum yields (0.3-1.0) reveal that lifetimes fairly accurately reflect radiative decay rates. An impressive correlation exists between the lifetime, τ, of the 4T1 (G) →6 A1 emission and the ligand, X: for X = Cl?, τ = 1.2 - 3,5 x 10?3 sec; X = Br?, τ = 0.35 - 0.43 X 10?3 sec; X =l?, τ = 0.036 – 0.055 X 10?3 sec. We attribute this decreasing lifetime largely to the enhanced spin-orbital coupling associated with the heavier halide. We find that direct population of high energy charge-transfer (CT) states gives smaller emission yields than excitations in the ligand-field (LF) region. 相似文献
17.
Time-resolved mass spectroscopy has been utilized to study the kinetics of methylradical association. The rate coefficient for the association process was determined by following the time dependence of ethane formation after flash photolysis of CH3I in the presence of N2. The net rate coefficient for the process 2CH3 (+M) → C2H6(+M) has a high-pressure limit of (4.0 ± 0.3) × 10?11 cm3 molecule?1 sec?1 at 313°K. This rate coefficient has found to be insensitive to the third-body number densities for pressures ranging from 13 Torr down to below 0.5 Torr, indicating that the lifetime for dissociation of the intermediate C2H6* species is greater than 2 × 10?7 sec at 313°K for a gas pressure of 0.5 Torr. 相似文献
18.
The rate constant for the reaction Br + O3 → BrO + O2 has been measured over the temperature range 224 to 422 K in a discharge flow system using a mass spectrometer as a detector. Results, expressed in the form k1 = (3.34 ± 0.40) × 10?11 X exp[?(978 ± 36)/T] cm3 s?1, are compared with previous measurements. 相似文献
19.
Inert-gas halide emission spectra from a Tesla discharge are studied as a function of pressure and temperature. From the temperature dependence of the infinite pressure ratio of broad-band (C → A and B → A) emission to B → X emission, the energy separations, TeC - TeB, are found to be ?130 cm?1 (XeCl), ?80 cm?1 (XeBr) and 375 cm?1 (KrCl). Estimates of the (C → A)/(B → X) spontaneous emission branching ratios agree well with theoretical predictions. 相似文献
20.
The laser-excitation spectrum of the transition X 2Σ+ → A 2Π of NaAr has been investigated using a supersonic expansion of a mixture of sodium vapor and argon gas for production of the molecules. In comparison to preyous investigations the rotational constants of the vibrational levels ν″ = 2, 3 and 4 of the X 2Σ+ state could in addition be determined. From our results we deduce a value of Re = 5.008(5) × 10?10 m for the equilibrium internuclear distance and of De = 41.7(δ) cm?1 for the well depth of the X 2Σ+ state. 相似文献