Applied Magnetic Resonance最新文献_第10页

Visualization of Conductors Inside an MRI Coil 磁共振成像线圈内导体的可视化

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-06-16 DOI: 10.1007/s00723-024-01666-8

Nikolay V. Anisimov, Lev L. Gervits, Arina A. Tarasova

{"title":"Visualization of Conductors Inside an MRI Coil","authors":"Nikolay V. Anisimov, Lev L. Gervits, Arina A. Tarasova","doi":"10.1007/s00723-024-01666-8","DOIUrl":"10.1007/s00723-024-01666-8","url":null,"abstract":"<div><p>This article reports on the use of fluorocarbons as an imaging medium in MRI. The function of this medium is to uniformly fill the space intended for MR scanning and to provide a strong signal against which objects of interest can be visualized. In our case, such objects were coils used as signal sensors in MRI studies. The aim of the study is visualization of the conductors located inside of an MRI coil and, therefore, could not be visually assessed. To enable the conductor’s imaging, signal amplification from the imaging medium in the vicinity of the conductors was used. The physical phenomenon behind this effect is the fact that the magnetic field induced in the conductor by precessing spins, causing a current in it, which is recorded by the receiver, greatly increases with decreasing distance of the spins from the conductor. The fluorocarbons—octafluorocyclobutane gas—C<sub>4</sub>F<sub>8</sub>, as well as so-called dry water—perfluoro(2-methyl-3-pentanone)—CF<sub>3</sub>CF<sub>2</sub>C(O)CF(CF<sub>3</sub>)<sub>2</sub> can be used as a visualization medium. In both cases, MRI scan is performed to detect fluorine nuclei (<sup>19</sup>F). The method is most effective in active mode—when the coil to be examined is connected to the receiver. The application of the conductor visualization method was shown for three types of two-channel quadrature coils. The ability to visualize the conductors separately for each channel, including volumetric reconstructions, and to construct coil sensitivity maps was demonstrated. <sup>19</sup>F MR images of the coils were compared with their photographs, X-ray and proton MR images, and showed high correspondence.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 8","pages":"753 - 765"},"PeriodicalIF":1.1,"publicationDate":"2024-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552632","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

A New Deep Learning Framework for Accurate Intracranial Brain Hemorrhage Detection and Classification Using Real-Time Collected NCCT Images 利用实时采集的 NCCT 图像准确检测和分类颅内脑出血的新型深度学习框架

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-06-13 DOI: 10.1007/s00723-024-01661-z

Simarjeet Kaur, Amar Singh

{"title":"A New Deep Learning Framework for Accurate Intracranial Brain Hemorrhage Detection and Classification Using Real-Time Collected NCCT Images","authors":"Simarjeet Kaur, Amar Singh","doi":"10.1007/s00723-024-01661-z","DOIUrl":"10.1007/s00723-024-01661-z","url":null,"abstract":"<div><p>Brain hemorrhage is a critical medical condition that is likely to cause long-term disabilities and death. Timely and precise emergency care, incorporating the accurate interpretation of computed tomography (CT) images, plays a crucial role in the effective management of a hemorrhagic stroke. However, conventional artificial intelligence methods are capable enough to detect the presence or absence of hemorrhage but fail to detect multiple types of hemorrhage with high accuracy. To address this, the paper introduces an innovative Deep Learning based approach that automatically detects, segments, and classifies subtypes of intracranial hemorrhages. The proposed model is trained and evaluated on two different datasets. It is initially trained on a dataset of CT images from the Radiological Society of North America (RSNA) brain CT hemorrhage database, which contained 752,803 head non-contrast computer tomography images obtained from 2,200 patients. Furthermore, the model's performance is validated using a real-time CT dataset collected from a diagnostic lab, comprising 15,000 CT scan images from 176 patients. The proposed model surpasses standard benchmarks for detection and classification, achieving exceptional metrics. It showcases overall segmentation accuracy with a Dice score and Jaccard Index of 0.99 and 0.88 respectively, while the classification metrics include an accuracy of 0.99, precision, recall, and F1 score of 0.97, 0.98, and 0.97 respectively. When two expert radiologists independently assessed the predicted hemorrhage locations and subtypes, ensuring uniform specificity levels, they determined the observed rate of false positives per patient was less. These results validate its applicability as a dependable clinical decision support tool.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 6","pages":"629 - 661"},"PeriodicalIF":1.1,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141519280","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

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-06-07 DOI: 10.1007/s00723-024-01647-x

К.M. Salikhov

{"title":"Similarities and Differences in the Effect of Dipole–Dipole and Exchange Interactions on the Shape of the EPR Spectrum of Dilute Solutions of Paramagnetic Particles","authors":"К.M. Salikhov","doi":"10.1007/s00723-024-01647-x","DOIUrl":"10.1007/s00723-024-01647-x","url":null,"abstract":"<div><p>Spin exchange caused by the exchange interaction during bimolecular collisions of paramagnetic particles in dilute solutions causes several effects: broadens the resonance lines of the EPR spectrum, changes the resonance frequencies, changes the shape of the resonance lines of the spectrum, and causes the effect of the exchange narrowing of the spectrum. The well-established belief is that the dipole–dipole interaction between paramagnetic particles only broadens the resonance lines. According to the new paradigm of spin exchange, the dipole–dipole interaction causes effects similar to the effects of spin exchange. In this article, a detailed quantitative analysis of the effect of the dipole–dipole interaction on the shape of the EPR spectra of dilute solutions of paramagnetic particles is carried out for the model system. It is shown that the contribution of the dipole–dipole interaction to the spin coherence transfer between particles makes it possible to more accurately determine the rate of spin exchange and, as a result, the rate of bimolecular collisions of molecules from the analysis of the shape of the EPR spectra. An experimental protocol is proposed that definitely highlights the contribution of the dipole–dipole interaction to the transfer of spin coherence.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 12","pages":"1587 - 1603"},"PeriodicalIF":1.1,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141370893","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

NMR Spectroscopy as an Alternative Analytical Method for Biopolymers Without Chromophore: Example of Hyaluronic Acid in Dietary Supplements 核磁共振光谱法作为无色团生物聚合物的替代分析方法：以膳食补充剂中的透明质酸为例

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-06-05 DOI: 10.1007/s00723-024-01663-x

Fabienne M. Lang, Klaudia Adels, Bernd W. K. Diehl, Margit Schulze, Yulia B. Monakhova

{"title":"NMR Spectroscopy as an Alternative Analytical Method for Biopolymers Without Chromophore: Example of Hyaluronic Acid in Dietary Supplements","authors":"Fabienne M. Lang, Klaudia Adels, Bernd W. K. Diehl, Margit Schulze, Yulia B. Monakhova","doi":"10.1007/s00723-024-01663-x","DOIUrl":"10.1007/s00723-024-01663-x","url":null,"abstract":"<div><p>To respond to the increasing demand for hyaluronic acid (HA) in dietary supplements (DSs) and nutricosmetics marketed for the treatment of osteoarthritis or moistening, it is essential to have an accurate and reliable method for its analysis in the final products. The study aimed to develop and validate alternative method for the quality control of HA in DSs using low-field (LF) and high-field (HF) nuclear magnetic resonance (NMR) spectroscopy at 80 MHz and 600 MHz, respectively. Moreover, chondroitin sulphate (CH), another active ingredient in DSs, can be simultaneously quantified. The <sup>1</sup>H-NMR methods have been successfully validated in terms of limit of detection (LOD) and limit of quantitation (LOQ), which were found to be 0.1 mg/mL and 0.2 mg/mL (80 MHz) as well as 0.2 mg/mL and 0.6 mg/mL (600 MHz). Recovery rates were estimated to be between 92 and 120% on both spectrometers; precision including sample preparation was found to be 4.2% and 8.0% for 600 MHz and 80 MHz, respectively. Quantitative results obtained by HF and LF NMR were comparable for 16 DSs with varying matrix. HF NMR experiments at 70 ℃ serve as a simple and efficient quality control tool for HA and CH in multicomponent DSs. Benchtop NMR measurements, upon preceding acid hydrolysis, offer a cost-effective and cryogen-free alternative for analyzing DSs in the absence of CH and paramagnetic matrix components.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 7","pages":"687 - 700"},"PeriodicalIF":1.1,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00723-024-01663-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141382139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Knee Model Construction Using Deep Neural Networks with Boundary Information for Local SAR Estimation 利用带边界信息的深度神经网络构建膝关节模型，用于局部合成孔径雷达估算

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-06-03 DOI: 10.1007/s00723-024-01662-y

Liang Xiao, Hongjin Ren, Hangyu Zhou, Cangju Xing

{"title":"Knee Model Construction Using Deep Neural Networks with Boundary Information for Local SAR Estimation","authors":"Liang Xiao, Hongjin Ren, Hangyu Zhou, Cangju Xing","doi":"10.1007/s00723-024-01662-y","DOIUrl":"10.1007/s00723-024-01662-y","url":null,"abstract":"<div><p>The local specific absorption rate (SAR) is a key safety indicator in high-field MRI. Constructing a specific model for each patient is important for accurate estimation of local SAR. The aim of this study is to construct subject-specific knee models based on low-field images for realizing accurate local SAR estimation in high-field MRI systems (3T and 1.5T). The proposed method used two U-Net networks for tissue segmentation of knee joint and the classification results of the two networks were merged to generate the final models. Muscle has high dielectric properties and large volume, which have an important influence on the electromagnetic field distribution. To improve the accuracy of muscle segmentation, a U-Net making use of boundary information was used to segment muscle alone to overcome the problem of inhomogeneous intensity at the edge of the muscle region. Other tissues were segmented by another U-Net, which used a weighted loss function to mitigate the adverse influence of class imbalances between tissues. The proposed method was compared with other methods using manual delineation as the standard. Its muscle segmentation performance was better than that of the comparison methods. On the other hand, local SAR in 3T using models constructed by these methods was also evaluated through electromagnetic simulation separately. It was shown that the maximum SAR<sub>10g</sub> of the models constructed by the proposed method was much closer to that of manual delineation on the whole. These results validated the availability of the proposed method.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 7","pages":"663 - 685"},"PeriodicalIF":1.1,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141259783","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

Scavenger-Based Immobilized Rh and Ir Complexes in Hydrogenation of Propyne and Propene with Parahydrogen 丙炔和丙烯与对氢的加氢反应中基于清除剂的固定化 Rh 和 Ir 复合物

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-05-22 DOI: 10.1007/s00723-024-01660-0

Ivan V. Skovpin, Dudari B. Burueva, Larisa M. Kovtunova, Anna V. Nartova, Ren I. Kvon, Valerii I. Bukhtiyarov, Igor V. Koptyug

{"title":"Scavenger-Based Immobilized Rh and Ir Complexes in Hydrogenation of Propyne and Propene with Parahydrogen","authors":"Ivan V. Skovpin, Dudari B. Burueva, Larisa M. Kovtunova, Anna V. Nartova, Ren I. Kvon, Valerii I. Bukhtiyarov, Igor V. Koptyug","doi":"10.1007/s00723-024-01660-0","DOIUrl":"10.1007/s00723-024-01660-0","url":null,"abstract":"<div><p>The immobilization of dimeric [M<sub>2</sub>(COD)<sub>2</sub>(μ–Cl)<sub>2</sub>] complexes (M – Rh or Ir) by the interaction with -SH groups of 3-mercaptopropyl-functionalized silica gel leads to Rh<sub>Cl</sub>–S–SiO<sub>2</sub> and Ir<sub>Cl</sub>–S–SiO<sub>2</sub> catalysts active in hydrogenations of propene and propyne. Nuclear magnetic resonance enhancement in parahydrogen-induced polarization experiments was studied in a wide range of hydrogenations conditions (25–120 °C, 1.0–3.9 bar). The structural transformations were studied using ex situ X-ray photoelectron spectroscopy (XPS). It was established that Ir<sub>Cl</sub>–S–SiO<sub>2</sub> demonstrated greater thermal stability in the hydrogenation of both propene and propyne in comparison with Rh<sub>Cl</sub>–S–SiO<sub>2</sub>. The beneficial effect of propyne was elucidated for thermal stability of studied catalysts and for the efficiency of the pairwise hydrogen addition. This can be explained by more efficient binding of the C≡C triple bond to an active center. The increase in reaction pressure typically leads to higher conversion in hydrogenations for both catalysts, but also decreases the temperatures sufficient for the reduction of anchored complexes with the formation of metal nanoparticles, which was confirmed by XPS.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 10","pages":"1275 - 1291"},"PeriodicalIF":1.1,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141110775","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

PELDOR to the Metal: Cu(II)-Based Labels Put a New Spin on Distance Measurements PELDOR to the Metal：基于铜(II)的标签为距离测量注入了新的活力

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-05-18 DOI: 10.1007/s00723-024-01658-8

Joshua Casto, Shramana Palit, Sunil Saxena

{"title":"PELDOR to the Metal: Cu(II)-Based Labels Put a New Spin on Distance Measurements","authors":"Joshua Casto, Shramana Palit, Sunil Saxena","doi":"10.1007/s00723-024-01658-8","DOIUrl":"10.1007/s00723-024-01658-8","url":null,"abstract":"<div><p>Eighty years ago, the advent of electron paramagnetic resonance (EPR) revolutionized our ability to observe the physical world of unpaired electron spins. The inception of EPR spawned multiple scientific areas with a focus on discerning the roles of paramagnetic metals and organic radicals in an array of processes and materials. More recently, the emergence of site-directed spin labeling combined with distance measurement technology and molecular modeling has harnessed the power of EPR, to ‘watch proteins move’. Spin labels have enabled the measurement of distance constraints and site-specific dynamics in biomolecules to provide rich details of structure and structural changes that are tightly linked to biological function. Historically, nitroxide radicals are the most common spin labels. However, decades of method development and technological innovation have created a plethora of spin label types to extend the reach of EPR throughout the realm of biophysics. In this review we overview recent developments that improve the sensitivity of distance measurements using Cu(II) labels. These achievements over the last three years promise advancements in the ability of EPR to measure structural and dynamical constraints beyond what is possible using common spin labels. First, we briefly discuss pulsed and continuous-wave EPR techniques that discern the coordination of Cu(II) to monitor spin-labeling efficiency and binding in biological environments. Next, we outline the bottlenecks that impact sensitivity in pulsed dipolar spectroscopy and the strategic steps taken to remove these bottlenecks to collect distance measurements in hours. More precisely, we focus on the fast-spin phase memory relaxation time, the broad EPR spectrum due to anisotropy, and orientational selectivity effects inherent to Cu(II). Finally, we showcase the versatile application of Cu(II) spin labels in biological systems and the advantages of Cu(II) in pulsed dipolar spectroscopy to access nanomolar protein concentrations.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 9","pages":"889 - 922"},"PeriodicalIF":1.1,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141063385","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

Calculation of the Matrix Elements of the Long-Range Coulomb Interaction Comparison of the GTO and STO Approaches 远距离库仑相互作用矩阵元素的计算 GTO 和 STO 方法的比较

IF 1.1 4区物理与天体物理

Applied Magnetic Resonance Pub Date : 2024-05-18 DOI: 10.1007/s00723-024-01659-7

O. A. Anikeenok

引用次数: 0

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 1.1 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":"10.1007/s00723-024-01657-9","url":null,"abstract":"<div><p>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 <i>a</i> 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 <i>a</i> 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<i> a</i> 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.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":"55 12","pages":"1569 - 1585"},"PeriodicalIF":1.1,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00723-024-01657-9.pdf","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":"OA","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