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electron paramagnetic resonance study of amphiphiles partitioning behavior in desiccation-tolerant moss during dehydration

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Chinese Chemical Letters 2007年第7期18卷 865-868页

作者： Shu Jun Xu Wei Hong Chen Ying Wen Chen Cui Fang Wang Yan Wang School of Environmental Science and Engineering Shanghai Jiaotong University Shanghai 200240 China Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

Desiccation tolerance is a crucial characteristic for desert moss surviving in arid regions. Desiccation procedure always induces amphiphiles transferring from the polar cytoplasm into lipid bodies. The behavior of amphiphiles transferring can contribute to the enhancement of desiccation tolerance and the reduction of plasma membrane integrity simultaneously. The effects of amphiphiles partitioning into the lipid phase during water loss has been studied for pollen and seeds using electron paramagnetic resonance （EPR） spectroscopy. However, desiccation-tolerant high plants occur among mosses, several angiosperms and higher plants seeds or pollens. They have different strategies for survival in dehydration and rehydration. A desiccation-tolerant moss Tortula desertorurn was used to investigate the behaviors of amphiphilic molecules during drying by spin label technology. There are small amount of amphiphilic probes partitioning into membrane during moss leaves dehydration, comparing with that in higher plants. Cytoplasm viscosity changed from 1.14 into glass state only dehydration less than 60 min. Moss leaves lost plasma membrane integrity slightly,from 0.115 to 0.237, occurred simultaneously with amphiphiles partition. The results showed the more advantages of mosses than higher plants in adapting fast dehydration. We propose that EPR spin label is feasible for studying the amphiphiles partitioning mechanisms in membrane protection and damage for desiccation-tolerant mosses.

关键词： Plasma membrane permeability Amphiphiles partition Desiccation tolerance electron paramagnetic resonance Tortula desertorum broth. Mosses

electron paramagnetic resonance in monitoring of nitric oxide production after kidney transplantation in rats

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Chinese Medical Journal 2004年第10期117卷 1552-1557页

作者：徐涛陈希王晓峰黄晓波曲星珂叶海云张小东侯树坤朱积川 Department of Urology Peking University People’s Hospital Beijing 100044 China Department of Cell Biology and Genetics Peking University Health Science Center Beijing 100083 China

Background Much research has been focused on ischemia/reperfusion injury (IRI) to the transplanted organs. As a free radical, nitric oxide (NO) plays an important role in IRI. In this study, the production of NO and its functions during IRI were monitored in rat models after allotransplantation of kidney *** Of 75 male LEW rats, 30 served as donors, and the remaining 45 rats were divided into three groups (15 rats in each group): controls (group 1), kidney allotransplantation followed by bilateral nephrectomy during reperfusion (group 2), 2 hours before operation, donors and recipients were treated with NG-nitro L-arginine methyl ester (L-NAME), a NO synthase inhibitor, at a dose of 30 mg/kg (group 3). Bilateral nephrectomies were performed while kidney grafts were reperfused. The kidney grafts were hypothemically stored for 24 hours. The production of NO before and after reperfusion was measured by electron paramagnetic resonance (EPR). The creatinine level, the glomerular filtration rate (GFR) and the protein carbonyl content in tissue samples were recorded on the first and the fifth day after operation. The data were evaluated by one-way analysis of variance. Differences were considered to be statistically significant when a P value was less than *** After reperfusion for 15 minutes, the production of NO increased remarkably and kept increasing till 120 minutes, after which the level returned to normal. In group 3, which was pretreated with L-NAME, creatinine levels were higher than those in group 2 at the 24th hour (4.10±0.50 mg/dl vs. 3.77±0.42 mg/dl, P<0.05) and the 120th hour (3.19±0.79 mg/dl vs. 2.22±0.53 mg/dl, P<0.05). GFR levels in group 3 were lower than those in group 2 at the 24th hour (0.50±0.12 ml/min vs. 0.71±0.19 ml/min, P<0.05) and the 120th hour (0.59±0.38 ml/min vs. 1.27±0.23 ml/min, P<0.01). The content of protein carbonyl in tissue samples of group 3 was lower than that in group 2 at the 24th hour (29.01±7.02 nmol/mg pro

关键词： nitric oxide · kidney transplantation · ischemia/reperfusion injury · electron paramagnetic resonance

A low-noise X-band microwave source with digital automatic frequency control for electron paramagnetic resonance spectroscopy

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Chinese Physics B 2023年第8期32卷 46-51页

作者：贺羽康润琪石致富荣星 CAS Key Laboratory of Microscale Magnetic resonance and School of Physical Sciences University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Chinainstru&Quantumtech(Hefei)Co. LtdHefei 230031China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

We report a new design of microwave source for X-band electron paramagnetic resonance *** microwave source is equipped with a digital automatic frequency control *** parameters of the digital automatic frequency control circuit can be flexibly configured for different experimental conditions,such as the input powers or the quality factors of the *** configurability makes the microwave source universally compatible and greatly extends its *** demonstrate the ability of adapting to various experimental conditions,the microwave source is tested by varying the input powers and the quality factors of the resonator.A satisfactory phase noise as low as-135 d Bc/Hz at 100-k Hz offset from the center frequency is achieved,due to the use of a phase-locked dielectric resonator oscillator and a direct digital ***-wave electron paramagnetic resonance experiments are conducted to examine the performance of the microwave *** outstanding performance shows a prospect of wide applications of the microwave source in numerous fields of science.

关键词： electron paramagnetic resonance X-band microwave source automatic frequency control

Developing in situ electron paramagnetic resonance characterization for understanding electron transfer of rechargeable batteries

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Nano Research 2023年第10期16卷 11992-12012页

作者： Bin Wang Wanli Wang Kang Sun Yujie Xu Yi Sun Qiang Li Han Hu Mingbo Wu State Key Lab of Heavy Oil Processing Institute of New EnergyCollege of Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580China Institute of Chemical Industry of Forest Products Chinese Academy of ForestryNanjing 210042China College of Physics Qingdao UniversityQingdao 266071China

Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable *** facilitate the development of these devices,it is important to gain insight into the underlying the single-/multi-electron transfer *** can be achieved through in-time detection under operational conditions,but there are limited tools available for monitoring electron transfer under operando *** paramagnetic resonance(EPR)is a powerful technique that can meet these expectations,as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic *** the long history of in situ electrochemical EPR research,its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing *** review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR,with the aim of drawing researchers’attention to this powerful *** introducing the fundamental principles of EPR,we describe the critical advances made in detecting batteries using operando EPR,along with the remaining challenges and opportunities for future development of this technology in *** emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world *** believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research,and ultimately contribute to the development of more efficient and sustainable energy storage devices.

关键词： electron paramagnetic resonance in situ energy storage battery

Elucidating solvent effects on the stability of phenoxyl radicals in monohydric alcohols via electron paramagnetic resonance

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Green Chemical Engineering 2024年第4期5卷 483-488页

作者： Xinyu Wang Wenjing Sun Yongtao Wang Haoran Li Department of Chemistry Zhejiang UniversityHangzhou310058China Center of Chemistry for Frontier Technologies ZJU-NHU United R&D CenterZhejiang UniversityHangzhou310058China State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310058China

Research on solvent effects is an important and long-standing topic,but there still is some room,especially for the special solvent effect of *** this work,we investigated the stability of phenoxyl radical in monohydric alcohol solvents through in-situ electron paramagnetic resonance *** decay behavior of phenoxyl radical showed a reasonable relationship with the mesoscopic structure of alcohols,characterized by smalland wide-angle X-ray ***,the distinct solvent effects of fluoroalcohols were emphasized,and the significant influence of van der Waals distance in the solvents was ***,the stability of phenoxyl radical in alcohols was quantified and correlated with the solvent *** believe that the established method for stability study on radicals will encourage solvent effect studies on various organic reactions,and the proposed solvent effects in fluoroalcohols may inspire the development of green solvents in both industrial conversions and organic synthesis.

关键词： Solvent effect Fluoroalcohol Phenoxyl radical Stability electron paramagnetic resonance

Theoretical Studies of electron paramagnetic resonance Parameters for Cr^4＋ Ions in Ca2GeO4 Crystals

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Communications in Theoretical Physics 2005年第2期43卷 337-340页

作者： WUXiao-Xuan ZHENGWen-Chen MEIYang DepartmentofMaterialScience SichuanUniversityChengdu610064China／／DepartmentofPhysicsCivilAviationFlyingInstituteofChinaGuanghan618307China DepartmentofMaterialScience SichuanUniversityChengdu610064China／／InternationalCenterforMaterialsPhysics，theChineseAcademyofSciencesShenyang110016China DepartmentofMaterialScience SichuanUniversityChengdu610064China

The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting Dand g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from thecomplete high-order perturbation formulas of EPR parameters for a 3d~2 ion in trigonal MX_4clusters. In these formulas, in addition to the contributions to EPR parameters from the widely usedcrystal-field (CF) mechanism, the contributions from the charge-transfer (CT) mechanism (which areoften neglected) are included. From the calculations, it is found that for the high valence state3d~n ions in crystals, the reasonable explanation of EPR parameters (in particular, the g factors)should take both the CF and CT mechanisms into account.

关键词： crystal- and ligand-field theory electron paramagnetic resonance charge-transfer mechanism optical spectroscopy tunable laser crystal

electron paramagnetic resonance ——An effective method to monitor the protein unfolding

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Progress in Natural Science:Materials International 1997年第2期 118-120页

作者：舒占永 Beijing 100101 China Chinese Academy of Sciences Institute of Biophysics State Key Laboratory of Biomacromolecules

Generally, electron paramagnetic resonance (EPR) can be used to study the metallo-proteins which either contain paramagnetic ions, or could be reconstituted with paramagnetic ions. The substitution or the oxidation-reduction of the metal ions in the enzyme can be monitored visually using EPR through the variation of EPR signals. However, EPR analysis is not sensitive to the

关键词： electron paramagnetic resonance protein unfolding conformational changes.

In Situ electron paramagnetic resonance Reveals Fading Mechanism of Mn-Based Prussian Blue Analogue:Accelerated Mn Dissolution Due to Charge Delocalization

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Renewables 2024年第5期2卷 341-352页

作者： Xiaobing Lou Zonglin Li Shinuo Kang Yufan Li Sen Ma Fushan Geng Bingwen Hu Shanghai Key Laboratory of Magnetic resonance School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241 School of Physics and Electrical Engineering Anyang Normal UniversityAnyang 455000 State Key Laboratory of Space Power Sources Shanghai Institute of Space Power-SourcesShanghai 200245

Contrasting with Fe-based Prussian blue analogues(PBAs),Mn-based PBAs with higher energy density are more promising cathode materials for Na-ion ***,fast capacity fading has severely impeded its practical use,which is still not well *** elucidate the fading mechanism,in situ and ex situ electron paramagnetic resonance are employed *** results first demonstrate the charge delocalization of Mn2+and Mn dissolution during cycles,which are further proved to be highly *** work reveals the inherent shortcoming of Mn-based PBA cathodes in liquid electrolyte.

关键词： electron paramagnetic resonance fading mechanism Prussian blue analogues sodium-ion batteries Mn dissolution

Identification of Superoxide O2^- during KNO3-NaNO2-NaNO3 Salt by electron UV-Vis Absorption Spectroscopy Thermal Decomposition of Molten paramagnetic resonance and

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Chinese Journal of Chemical Physics 2017年第4期30卷 372-378,I0001页

作者：刘舒婷苏涛张鹏费泽杰刘洪涛中国科学院上海应用物理研究所熔盐化学与工程技术部上海201800

On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt （HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3）. It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS.

关键词： Superoxide Decomposition of heat transfer salt High temperature UV-visible electron paramagnetic resonance