Applied Magnetic Resonance最新文献_第7页

Exploring the Triplet State of Chlorophyll a in Mesoporous Silica Matrices by Time-Resolved EPR 通过时间分辨 EPR 探索介孔二氧化硅基质中叶绿素 a 的三重态

IF 1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-05-06 DOI: 10.1007/s00723-024-01657-9

Samuel Zatta, Andrea Calcinoni, Alessandro Agostini, Silvia Leccese, Thomas Onfroy, Claude Jolivalt, Alberto Mezzetti, Marco Bortolus, Donatella Carbonera

{"title":"Exploring the Triplet State of Chlorophyll a in Mesoporous Silica Matrices by Time-Resolved EPR","authors":"Samuel Zatta, Andrea Calcinoni, Alessandro Agostini, Silvia Leccese, Thomas Onfroy, Claude Jolivalt, Alberto Mezzetti, Marco Bortolus, Donatella Carbonera","doi":"10.1007/s00723-024-01657-9","DOIUrl":"https://doi.org/10.1007/s00723-024-01657-9","url":null,"abstract":"Chlorophyll is a pivotal molecule in photosynthesis due to its ability to absorb solar light and start the photochemical process. The chlorophyll triplet state is easily populated from the light-induced singlet excited state via Intersystem Crossing (ISC) and can react with oxygen generating singlet oxygen, posing a threat to the stability of chlorophyll, but also an opportunity for photodynamic therapy. Here, we focus on the study of the photo-physical properties of chlorophyll a and WSCP (Water-Soluble Chlorophyll Protein, a protein binding the pigment), which have been adsorbed in mesoporous silica matrices. We adopt SBA-15, a silica matrix with well-ordered hexagonal structure with pores of 70 Å of diameter. The triplet formed upon illumination in these systems is studied by time-resolved EPR spectroscopy. Analysis of the EPR spectra shows that the triplet state is very sensitive to the inclusion in the pores of SBA-15 modifying its spin polarization. Chl a in SBA-15 loses its central metal ion, while its structure remains unchanged if the mesoporous silica is previously soaked into a basic solution before Chl a adsorption, as revealed by its zero-field splitting parameters of the triplet state. WSCP is readily included in the silica matrix, but its embedded pigments are no longer protected by the protein core.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"2013 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140887191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synthesis of Yb3+-Doped Cs2NaScF6 Single Crystals and EPR Spectroscopy of the Dopant Yb3+ ion 掺杂 Yb3+ 的 Cs2NaScF6 单晶的合成和掺杂 Yb3+ 离子的 EPR 光谱分析

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-30 DOI: 10.1007/s00723-024-01656-w

M. L. Falin, V. A. Latypov, N. M. Khaidukov

引用次数: 0

Design of Inside-Out Magnetic Resonance Sensor Based on Coordinate Search Method 基于坐标搜索法设计内向外磁共振传感器

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-24 DOI: 10.1007/s00723-024-01649-9

Jiamin Wu, Zheng Xu, Yanhe Zhu, Yucheng He

{"title":"Design of Inside-Out Magnetic Resonance Sensor Based on Coordinate Search Method","authors":"Jiamin Wu, Zheng Xu, Yanhe Zhu, Yucheng He","doi":"10.1007/s00723-024-01649-9","DOIUrl":"10.1007/s00723-024-01649-9","url":null,"abstract":"<div>The application of inside-out magnetic resonance sensors has emerged as a focal point in soil moisture detection, offering a non-invasive approach crucial for evaluating soil physical structure. While existing inside-out magnetic resonance sensors with a unilateral structure can effectively measure the shallow soil layer, they fall short in assessing deeper soil layers (1–10 cm). However, the lack of optimal design and horizontal comparison among relevant sensors has impeded the widespread adoption of magnetic resonance sensors in soil moisture measurement. This paper addresses this gap by optimizing a magnetic resonance sensor with a dumbbell structure. The magnet structure is fine-tuned using a non-derivative optimization method, specifically the coordinate search, under practical engineering constraints to establish a uniform field in the region of interest. Employing the coordinate search method enhances the sensor’s relative signal-to-noise ratio (SNR) to its maximum. Artificial soil samples are then tested, and the T2 spectrum distribution reveals insights into water distribution characteristics across different pores.</div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 6","pages":"599 - 613"},"PeriodicalIF":1.1,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140664340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of Magnetic Resonance Imaging (MRI) Phantom With Arbitrary T1 Value Using Dextrin Hydrate 利用糊精水合物开发具有任意 T1 值的磁共振成像（MRI）模型

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-21 DOI: 10.1007/s00723-024-01655-x

Yusuke Sato, Daiki Ito, Norio Hayashi, Kouichi Ujita, Takayuki Suto, Haruyuki Watanabe, Yoshito Tsushima

{"title":"Development of Magnetic Resonance Imaging (MRI) Phantom With Arbitrary T1 Value Using Dextrin Hydrate","authors":"Yusuke Sato, Daiki Ito, Norio Hayashi, Kouichi Ujita, Takayuki Suto, Haruyuki Watanabe, Yoshito Tsushima","doi":"10.1007/s00723-024-01655-x","DOIUrl":"10.1007/s00723-024-01655-x","url":null,"abstract":"<div>To formulate the relationship between the dextrin hydrate concentration and T1 relaxation rate and create a magnetic resonance imaging (MRI) phantom with an arbitrary T1 value. Dextrin solution with nine different concentrations was prepared by dissolving 0–20 g (2.5 g increments) of dextrin in 25 g of purified water. The T1 values of the phantoms were measured using a 1.5 T MR scanner, and the relationship between the R1 value and dextrin concentration was regressed using linear and quadratic equations. Phantoms with concentrations adjusted to T1 values of 500, 1000, and 1500 ms were created from each regression equation, and the errors between the measured T1 and target values were evaluated. In addition, the temporal changes in the T1 and T2 values of the phantoms were also evaluated. The T1 and T2 values ranged from 367.4 ± 14.1 to 2577.6 ± 76.5 ms and 20.0 ± 0.9 to 1805.3 ± 8.3 ms, respectively. The linear and quadratic regression equations were (y=2.9631x+0.2043) and (y=1.8295{x}^{2}+1.4995x+0.37), with coefficients of determination of 0.9763 and 0.9954, respectively. The maximum errors were 12.3% and 2.1% for the linear and quadratic equations, respectively. The T1 value was maintained at a fluctuation rate of approximately 10% during the first 4 weeks. The T2 value decreased by approximately 20% after 4 weeks. MRI phantoms with arbitrary T1 values in the range of 500–1500 ms with an error within 2.1% can be created using dextrin, which can be used as human tissue-equivalent MRI phantoms for T1 of the grey or white matter of the brain, liver, pancreas, spleen, and prostate.</div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 5","pages":"497 - 507"},"PeriodicalIF":1.1,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140628410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Electron Spin Dynamics of the Photoexcited Triplet States of Bromoperylenebisimide Compounds: Computation and Analysis of the Electron Spin Polarization Evolution in TREPR Spectra 溴过二亚胺化合物光激发三重态的电子自旋动力学：TREPR 光谱中电子自旋极化演变的计算与分析

IF 1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-20 DOI: 10.1007/s00723-024-01654-y

A. Mambetov, A. Sukhanov, Xue Zhang, Jianzhang Zhao, V. Voronkova

{"title":"Electron Spin Dynamics of the Photoexcited Triplet States of Bromoperylenebisimide Compounds: Computation and Analysis of the Electron Spin Polarization Evolution in TREPR Spectra","authors":"A. Mambetov, A. Sukhanov, Xue Zhang, Jianzhang Zhao, V. Voronkova","doi":"10.1007/s00723-024-01654-y","DOIUrl":"https://doi.org/10.1007/s00723-024-01654-y","url":null,"abstract":"The dynamics of the photogenerated triplet electron spin polarization (ESP) of two perylenebisimide (PBI) derivatives, PBI-2Br and PBI-Br-NH, is studied by the time-resolved electron paramagnetic resonance (TREPR). The ESP inversion in the triplet TREPR spectra of two compounds is detected at delays after the laser pulse (DAF) of ~ 500–900 ns. A fairly efficient algorithm for the exact numerical solution of the equation of motion of the spin density matrix of an ensemble of photoexcited triplets taking into account the anisotropy of the decay rates of sublevels of the triplet state, spin–lattice and spin–spin relaxations is elaborated in order to analyze the ESP inversion of TREPR spectra. The calculated time evolution of the TREPR spectra and its fitting experimental ones shows that even a slight difference in decay rates for the triplet sublevels of PBI-2Br results in the ESP inversion in the TREPR spectra already at DAF of ~ 500 ns. At the same time, decay rates ( τX−1 = 4 µs−1; τY−1 = 4.4 µs−1; τZ−1 = 3.3 µs−1) are higher than those for the available examples of the ESP inversion of the triplet TREPR spectra. The replacement of a Br atom by NH leads to noticeable changes in the photoinduced properties of the triplet including decay rates (τX−1 = 1.25 µs−1; τY−1 = 0.125 µs−1; τZ−1 = 0.125 µs−1). PBI-Br-NH is characterized by an axial decay rate anisotropy with τx−1, which is ten times higher than τY−1 and τZ−1. The trend in the triplet lifetime change obtained from the TREPR spectra is consistent with the data of the nanosecond transient absorption spectra.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"12 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140630286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental Studies of Power-Saturated Spin Modes of Nitroxides in Liquids 1 液体中氮氧化物功率饱和自旋模式的实验研究 1

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-19 DOI: 10.1007/s00723-024-01651-1

Barney L. Bales, Miroslav Peric, Robert N. Schwartz

引用次数: 0

Estimation of Relaxation Times During Free Evolution from the SECSY Signal of an Electron–Nuclear Spin-Coupled System in a γ-Irradiated Malonic Acid Single Crystal 从γ-辐照丙二酸单晶中电子-核自旋耦合系统的 SECSY 信号估算自由演化过程中的弛豫时间

IF 1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-17 DOI: 10.1007/s00723-024-01653-z

Hamid Reza Salahi, Sushil.K. Misra

引用次数: 0

Towards Routine 7Li In Situ Solid-State NMR Studies of Electrochemical Processes in Li|LiPF6|LFP Cells 对 Li|LiPF6|LFP 电池中的电化学过程进行常规 7Li 原位固态 NMR 研究

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-11 DOI: 10.1007/s00723-024-01643-1

Edina Šić, Dominion Fredericks, Oliver Pecher, Sebastian Wegner, Hergen Breitzke, Vickram Singh, Gerd Buntkowsky, Torsten Gutmann

引用次数: 0

On the Microstructure and Dynamics of Membranes Formed by Lipid as From Stenotrophomonas maltophilia, a Member of Gut Microbiome: An EPR Study 关于肠道微生物群成员嗜麦芽僵直单胞菌脂质形成的膜的微观结构和动力学：一项 EPR 研究

IF 1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-11 DOI: 10.1007/s00723-024-01646-y

G. Vitiello, R. Esposito, I. Speciale, C. De Castro, G. D’Errico

{"title":"On the Microstructure and Dynamics of Membranes Formed by Lipid as From Stenotrophomonas maltophilia, a Member of Gut Microbiome: An EPR Study","authors":"G. Vitiello, R. Esposito, I. Speciale, C. De Castro, G. D’Errico","doi":"10.1007/s00723-024-01646-y","DOIUrl":"https://doi.org/10.1007/s00723-024-01646-y","url":null,"abstract":"Lipid As are the main components of the external leaflet of the outer membrane of Gram-negative bacteria. Their molecular structure has evolved to allow the bacteria survival in specific environments. In the present work, we investigate how and to what extent lipid membranes that include in their composition lipid A molecules of a bacterium of the gut microbiota, Stenotrophomonas maltophilia, differ from those formed by the lipid A of the common Gram-negative bacterium Salmonella enterica, which is not specific to the gut and is here used as a reference. Electron Paramagnetic Resonance (EPR) spectroscopy, using spin-labelled lipids as molecular probes, allows the segmental order of the acyl chain and the polarity across the bilayer to be analyzed in detail. Both considered lipid As cause a stiffening of the outermost segments of the acyl chains. This effect increases with increasing the lipid A content and is stronger for the lipid A extracted from Stenotrophomonas maltophilia than for that extracted from Salmonella enterica. At the same time, the local polarity of the bilayer region just below the interface increases. As the inner core of the bilayer is considered, it is found that the lipid A from Salmonella enterica causes a local disorder and a significant reduction of the local polarity, an effect not found for the lipid A from Stenotrophomonas maltophilia. These results are interpreted in terms of the different lengths and distributions of the acyl tails in the two lipid As. It can be concluded that the symmetrically distributed short tails of the lipid A from Stenotrophomonas maltophilia favors a regular packing within the bilayer.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"32 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

13C MAS NMR Mechanistic Study of Propene Transformation on Silver-Modified ZSM-5 Zeolite in the Presence of Molecular Oxygen 分子氧存在下银改性 ZSM-5 沸石上丙烯转化的 13C MAS NMR 机制研究

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-04-08 DOI: 10.1007/s00723-024-01652-0

Zoya N. Lashchinskaya, Anton A. Gabrienko, Alexander V. Toktarev, Alexander G. Stepanov

{"title":"13C MAS NMR Mechanistic Study of Propene Transformation on Silver-Modified ZSM-5 Zeolite in the Presence of Molecular Oxygen","authors":"Zoya N. Lashchinskaya, Anton A. Gabrienko, Alexander V. Toktarev, Alexander G. Stepanov","doi":"10.1007/s00723-024-01652-0","DOIUrl":"10.1007/s00723-024-01652-0","url":null,"abstract":"<div>Silver-modified zeolites have demonstrated promising properties for hydrocarbon feedstock valorization and the oxidation of organic compounds. Within the frame of the scientific interest for selective oxidation of light alkenes on metal-modified zeolites, the transformation of propene on Ag/H-ZSM-5 zeolite in the presence of molecular oxygen has been monitored by 13C (CP) MAS NMR spectroscopy at 296–773 K. Silver-allyl intermediate species have been detected by 13C CP/MAS NMR, indicating that Ag+ sites are involved in propene transformation. It is assumed that oxygen and propene compete for the Ag+ adsorption sites, thus prompting propene adsorption on zeolite Brønsted acid sites (BAS) and its further transformation by oligomerization and conjunct polymerization. Among the products of propene oxidation by molecular oxygen, only carbon dioxide has been detected by 13C MAS NMR, implying high activity of Ag/H-ZSM-5 in alkene total oxidation. It is thus inferred that silver-modified zeolite is not a promising catalyst for propene selective oxidation to propene oxide and carbonyl group containing organics.</div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 10","pages":"1263 - 1274"},"PeriodicalIF":1.1,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0